CN100440437C - Manufacturing method of thin film transistor, electro-optical device and electronic instrument - Google Patents

Abstract

An object of the present invention is to provide a technique for forming a gate electrode and a semiconductor film for a thin film transistor with submicron accuracy through a simple and inexpensive process. The method for manufacturing a thin film transistor provided by the present invention includes a method for forming a semiconductor film and/or a method for forming a gate electrode, wherein the method for forming a semiconductor film includes: a step of disposing a droplet (14) containing a semiconductor material on a substrate make the droplet dry, and form a semiconductor film (16) by depositing a semiconductor material at least at the peripheral portion of the droplet, and the method for forming the gate electrode includes: a step of disposing a droplet containing a conductive material; making the droplet drying, and depositing a conductive material on at least the periphery of the droplet to form a gate electrode.

Description

Manufacturing method of thin film transistor, electro-optical device and electronic instrument

field of invention

The present invention relates to a method of manufacturing a semiconductor film and a method of manufacturing a thin film transistor using the semiconductor film.

Background technique

Conventionally, as a method of forming a semiconductor film in a thin film transistor manufacturing process, a method of forming a thin film having a larger than necessary area using a semiconductor material and patterning the thin film to remove unnecessary portions has been widely used. In addition, the gate electrode is often produced by forming a conductive thin film of tantalum, aluminum, or the like, and patterning it.

As an example of the patterning method, photolithography is mentioned. Photolithography is a method in which a desired resist pattern is formed using a photomask on a wide thin film, and the portion not covered by the resist pattern is etched to form the thin film into a desired shape. In recent years, due to the high integration of semiconductor elements, the so-called sub-micron order forming technology smaller than 1 micron has become necessary, and the formation of finer mask patterns during etching or the resolution of X-rays and electron beam exposures with shorter wavelengths have become necessary. high rate method.

In addition, a thin film of a fine shape can also be formed by an inkjet method. For example, a method has been proposed in which a solution containing a semiconductor material such as an organic semiconductor material is discharged onto a substrate from an inkjet type discharge device to form a semiconductor film. In the case of ejection by the inkjet method, due to the wettability of the substrate surface, the ejected droplets spread due to wetting, and it may be difficult to accurately draw a fine pattern. Therefore, a method has been proposed in which a cell bank is formed in advance on the surface of a substrate to control the arrangement of droplets so that the discharged droplets are arranged in a desired pattern (for example, refer to Patent Document 1 or Patent Document 2).

[Patent Document 1] JP-A-59-75205

[Patent Document 2] JP-A-2000-353594

However, in photolithography, apparatuses for formation of fine patterns and exposure using X-rays and electron beams are expensive, and the throughput is low. In addition, in the inkjet method, the droplet diameter is more than several microns, so it is difficult to form a thin film on the order of submicron. In the method using the storage cell dam, in order to form the storage cell dam, it is necessary to use the photolithography method and the ink-jet method described above, thus causing problems of cost and efficiency.

Contents of the invention

Therefore, a first object of the present invention is to provide a method of manufacturing a thin film transistor capable of forming a semiconductor film for the thin film transistor with submicron precision through simple and inexpensive steps.

In addition, a second object of the present invention is to provide a method of manufacturing a thin film transistor capable of forming a gate electrode for a thin film transistor with submicron order of accuracy through simple and inexpensive steps.

Furthermore, a third object of the present invention is to provide a method of manufacturing a thin film transistor capable of forming a plurality of gate electrodes corresponding to a plurality of thin film transistors with submicron precision through simple and inexpensive steps.

In order to solve the above-mentioned first problem, a first aspect of the method for manufacturing a thin film transistor of the present invention is a method for manufacturing a thin film transistor including a semiconductor film, a channel region provided on the semiconductor film, and a channel region sandwiching the semiconductor film. The source region and the drain region, and the gate electrode opposite to the channel region through the gate insulating film include: the process of disposing liquid droplets containing semiconductor materials on the substrate; drying the liquid droplets to generate a closed-loop phenomenon. A step of depositing a semiconductor material in at least the peripheral portion of the droplet; and a step of forming a semiconductor film by removing the semiconductor material in the center portion of the droplet when the semiconductor material is deposited in the center portion of the droplet.

In general, the liquid droplets arranged on the substrate dry quickly at the peripheral portion (edge). Therefore, when a droplet contains a solute or a dispersed substance (hereinafter collectively referred to as a solute, etc.), during the drying process of the droplet, the concentration of the solute or the like in the periphery of the droplet first becomes saturated, and precipitation begins. On the other hand, a liquid flow from the central part of the droplet to the peripheral part is generated inside the droplet to replenish the droplet lost by evaporation at the peripheral part of the droplet, and the solute in the central part of the droplet travels to the peripheral part along with the flow, As the droplet dries, precipitation starts at the periphery. In this way, the phenomenon that the solute contained in the droplet is deposited in a ring shape along the outer periphery of the droplet shape arranged on the substrate is called "pinning".

A first aspect of the method for manufacturing a thin film transistor according to the present invention is characterized in that a droplet containing a semiconductor material is placed on a substrate, and the droplet is dried to deposit the semiconductor material around the droplet by a closed-loop phenomenon. Due to the closed loop phenomenon, a fine semiconductor film on the order of submicron can be formed in a simple process. In addition, the shape of the semiconductor film can be controlled by adjusting the drying rate and the wettability of the substrate surface on which the droplets are placed, and can be formed into a ring shape, or a circular or elliptical shape in which a thin film is also formed in the center. In any case, by causing a closed loop, shrinkage of the peripheral part during drying, shrinkage of the film, or flying out can be prevented. Also, when a thin film is formed at the center of the droplet, it can be processed into a fine shape by removing a part of it as described later.

In addition, the term "thin film transistor" used in this specification only includes a channel region provided on a semiconductor film, a source region and a drain region corresponding to the channel region, and a gate electrode opposed to the channel region through a gate insulating film. , its structure is not limited, and it may be a so-called overhead gate type in which a semiconductor film, a gate insulating film, and a gate electrode are sequentially stacked on an insulating substrate, or it may be a gate electrode, a gate insulating film, and a gate electrode on an insulating substrate. The so-called bottom gate type in which semiconductor films are stacked sequentially.

In the first aspect of the manufacturing method of the thin film transistor of the present invention, it is preferable that in the step of arranging the droplets, two or more droplets are arranged, and the peripheral portion of the droplet shape obtained when these droplets are fused in the semiconductor film material is preferably formed. Precipitate.

If two or more liquid droplets are arranged very close to each other or partially overlapped, the two or more liquid droplets will fuse due to the wet spread of each liquid droplet. As a result, the droplet shape can be changed in various ways, and the degree of freedom in the shape of the obtained semiconductor thin film is also increased. For example, linear droplets can be obtained by juxtaposing and fusing a plurality of droplets in a straight line. When the ring is closed by the linear droplet and a semiconductor material is precipitated at the peripheral portion thereof, a linear semiconductor film having a width on the order of submicrons can be obtained. In addition, instead of fusing all the droplets to form one large droplet, a linear semiconductor film can be obtained by repeatedly fusing two or more droplets and depositing a semiconductor film on the periphery thereof.

Furthermore, in the first aspect of the thin film transistor manufacturing method of the present invention, it is preferable to further include a step of increasing the concentration of the semiconductor film material in the peripheral portion of the droplet after the step of arranging the droplet.

As a step of increasing the concentration of the semiconductor film material in the peripheral portion of the droplet, for example, a step of adding a temperature gradient to the substrate on which the droplet is arranged to generate convection with the inside of the droplet; The process of dropping and overlapping spraying solvent (or dispersing solvent), etc. Through such a process, the semiconductor material concentrates on the peripheral portion of the droplet, and the deposition at the peripheral portion is promoted. As described above, even without this step, the liquid flow from the center of the droplet to the periphery occurs due to the concentration difference between the center of the droplet and the peripheral portion of the solute, but by this step, the semiconductor material is actively transported to the droplet. The flow at the periphery can more effectively prevent the semiconductor material from remaining in the center of the droplet.

The first aspect of the method for manufacturing a thin film transistor according to the present invention preferably further includes a step of removing a part of the semiconductor film to divide the semiconductor film after the step of forming the semiconductor film, and a step of forming gate electrodes corresponding to the divided semiconductor films. .

As the step of removing the semiconductor film, for example, a method of adding an organic solvent to elute the semiconductor material and remove each solvent, an etching method, and the like are mentioned. In the removal process, precision on the order of submicrons is not required, so it can be performed relatively inexpensively by etching. By dividing the semiconductor film in this way and forming gate electrodes corresponding to the respective semiconductor films, a plurality of fine thin film transistors can be formed with high density and high efficiency. In addition, when the droplet is dried, if the semiconductor material is also deposited in the center of the droplet in addition to the periphery of the droplet, by removing the semiconductor film in the center in the same way, only the fine semiconductor film in the periphery can be obtained.

Furthermore, the first aspect of the thin film transistor manufacturing method of the present invention preferably includes a step of planarizing the surface of the substrate before the step of arranging the liquid droplets.

The planarization process is performed, for example, by chemical mechanical polishing (CMP), etching, and the like. In addition, the method of forming a SOG (Spin On Glass) film in the spin coating method is also an excellent method for obtaining a flat surface in terms of cost. If the surface of the substrate is flat, the droplet wets and spreads uniformly, so the semiconductor film can be patterned with high precision.

In the first aspect of the manufacturing method of the thin film transistor of the present invention, it is preferable to irradiate heat or light energy to the semiconductor film obtained by loop closure. Examples of heat or light energy irradiation include rapid thermal processing (Rapid Thermal Process) (RTP) treatment and laser irradiation. Thereby, the crystallinity of the semiconductor film can be improved.

In addition, the first aspect of the thin film transistor manufacturing method of the present invention may further include a step of forming a source region and a drain region by implanting impurities into the semiconductor film after the step of forming the semiconductor film. Through this step, the semiconductor film described above can be used for a thin film transistor.

In addition, in order to solve the above-mentioned second problem, a second aspect of the method of manufacturing a thin film transistor of the present invention is a method of manufacturing a thin film transistor including a channel region provided on a semiconductor film, and a source corresponding to the channel region. region, drain region, and the gate electrode opposite to the channel region through the gate insulating film, which includes: a droplet disposition process, by controlling the wettability of the surface of the gate insulating film, disposing the droplets so that the droplet containing the conductive material The peripheral part is opposite to the channel region; and the precipitation step is to dry the liquid droplet to generate a closed-loop phenomenon, to deposit the conductive material at least in the peripheral part of the liquid droplet, and to deposit the above-mentioned semiconductor material in the central part of the liquid droplet Next, the gate electrode is formed by removing the above-mentioned semiconductor material in the central portion.

That is, the second aspect of the manufacturing method of the thin film transistor of the present invention is characterized in that by utilizing the above-mentioned "closed loop" phenomenon, the liquid droplets are arranged so that the periphery of the liquid droplets containing the conductive material faces the channel region, and the deposited The conductive film was used as the gate electrode. Due to the closed-loop phenomenon, a fine conductive film on the order of submicron can be formed with a simple process.

In the second aspect of the method for manufacturing a thin film transistor according to the present invention, it is preferable that in the droplet arrangement step, by controlling the wettability of the surface of the gate insulating film, the peripheral portion of the droplet is arranged to face the channel region. .

As a method of arranging so that the peripheral portion of the droplet faces the channel region by controlling the wettability, for example, forming a layer having a low affinity for a conductive material except at a position facing the channel region Surface-modified membranes (such as self-assembled monomolecular membranes (SAMs: Self-Assembled Monlayer), a method of disposing droplets containing conductive materials after the surface-modified membranes are formed. According to this method, conductive materials avoid forming affinity The low-resistance surface-modifying film region tends to deposit at the position facing the channel region.

In the second aspect of the manufacturing method of the thin film transistor of the present invention, it is preferable that the deposition step includes a step of removing the conductive material deposited in the center of the droplet.

As a method of removing the deposited conductive material, for example, a method of adding an organic solvent or an acidic solution to elute the conductive material and remove each solvent, an etching method, and the like are mentioned. In the removal process, precision on the order of submicrons is not required, so it can be performed relatively inexpensively by etching. By removing the conductive thin film in the central part, only the fine conductive thin film in the peripheral part can be obtained.

In the second aspect of the manufacturing method of the thin film transistor of the present invention, when a plurality of channel regions are provided on the semiconductor film of one thin film transistor, one or more droplets are arranged in the droplet arrangement step. The peripheral portion of the droplet is made to face the plurality of channel regions, and a plurality of gate electrodes respectively facing the plurality of channel regions are formed in the deposition step.

For example, in the case of a highly integrated structure in which a plurality of channels are provided on the semiconductor film of one thin film transistor, the gate electrode can be easily formed according to the manufacturing method of the benzene invention. The arrangement of the droplets can also be controlled by controlling the wettability as described above, and can also be controlled by adjusting the drying. By adjusting the drying, the conductive material is also deposited in the center of the droplet, and a circular or elliptical conductive thin film can also be formed. After forming the thin film, the thin film in the center can be removed to form a gate electrode.

In the second aspect of the manufacturing method of the thin film transistor of the present invention, it is preferable that the deposition step includes a removal step of removing a part of the conductive material deposited at the peripheral portion of the droplet, and in the removal step, the conductive material is disconnected so as to form opposing layers. A plurality of gate electrodes in the plurality of channel regions.

For example, a plurality of arc-shaped gate electrodes are formed by removing a portion of the conductive material formed in a ring-shaped break. With such a structure, a plurality of gate electrodes can be formed in a simple process, and a high-performance thin film transistor with a short gate length can be formed at a higher density.

In addition, in the second aspect of the manufacturing method of the thin film transistor of the present invention, it is preferable that in the droplet arrangement step, two or more droplets are arranged, and in the deposition step, the conductive material is placed on the above two or more droplets. At least the peripheral portion of the droplet shape obtained during fusion is precipitated.

As described above, by fusing two or more liquid droplets, the shape of the liquid droplets can be changed in various ways, and the degree of freedom in the shape of the obtained conductive thin film is also increased. For example, linear droplets can be obtained by juxtaposing and fusing a plurality of droplets in a straight line. When the loop is closed by the linear droplet and a conductive material is precipitated at its peripheral portion, a linear gate electrode pattern with a submicron order of width can be obtained. In addition, in addition to fusing all the droplets to form one large droplet, a linear conductive thin film can also be obtained by repeatedly fusing two or more droplets and depositing a conductive thin film on the periphery thereof.

In addition, in the second aspect of the manufacturing method of the thin film transistor of the present invention, it is preferable to further include a step of increasing the concentration of the conductive material in the peripheral portion of the droplet after the droplet arrangement step.

As a step of increasing the concentration of the conductive material in the peripheral portion of the droplet, for example, a step of adding a temperature gradient to the substrate on which the droplet is arranged to generate convection with the inside of the droplet; The process of dropping and overlapping spraying solvent (or dispersing solvent), etc. Through such a process, the conductive material gathers at the peripheral portion of the droplet, and the deposition at the peripheral portion is promoted. As described above, even without this step, the liquid flow from the center of the droplet to the periphery occurs due to the concentration difference between the center of the droplet and the periphery of the solute, but the conductive material is actively transported to the liquid by this step. The flow at the periphery of the droplet can more effectively prevent the conductive material from remaining in the center of the droplet.

In addition, the present invention also provides a semiconductor film including two channel regions, a source region and a drain region corresponding to the above-mentioned channel regions, and a gate electrode facing the above-mentioned two channel regions through a gate insulating film, forming the above-mentioned gate electrode. The conductive film of the electrode is a thin film transistor having a ring-shaped conductive film.

In the case of such a thin-film transistor, for example, in the case of an overhead gate type, liquid droplets containing a conductive material whose diameter is the distance between two channel regions can be placed on the gate insulating film to dry it and cause a closed-loop phenomenon. to manufacture. The gate length of the thin film transistor is on the order of submicron, and the extremely short gate electrodes are formed at high density with tiny intervals, so it can be highly integrated.

In addition, in the case of a thin film transistor having the above-mentioned two channel regions, a set of source region and drain region sandwiching the two channel regions may be formed, or two thin film transistors may be formed corresponding to each of the two channel regions. transistor. As an application of the former, a so-called multi-gate thin film transistor in which three or more gate electrodes are formed corresponding to one set of source regions and drain regions is also included in the present invention. As the current supplied increases, the portion of the gate electrode increases, and the performance is also improved. In addition, when the amount of current is equal, the current per one gate electrode is reduced, and current loss and heat generation can be suppressed, which is preferable. In addition, in the latter case, that is, in the case where two thin film transistors are formed corresponding to each of the two channel regions, one of the two thin film transistors corresponds to an N-channel MOS transistor, and the other may correspond to a P-channel MOS transistor. Complementary MOS transistors of type MOS transistors.

In addition, in order to solve the above-mentioned third problem, a third aspect of the method of manufacturing a thin film transistor of the present invention is a method of manufacturing two or more thin film transistors including a semiconductor film including a channel region, and sandwiching the channel region. The source region and the drain region facing the channel region, and the gate electrode facing the above-mentioned channel region through the gate insulating film are characterized in that they include: arranging process, by controlling the wettability of the surface of the gate insulating film, arranging the conductive material a liquid droplet, so that at least a part of the peripheral portion of the liquid droplet faces one or more of the channel regions; a deposition step, forming the gate electrode by depositing the conductive material only at the peripheral portion of the liquid droplet, wherein the Each of the aforementioned gate electrodes is connected to at least one other gate electrode.

That is, in the third aspect of the manufacturing method of the thin film transistor of the present invention, by using the above-mentioned "closed-loop phenomenon", droplets containing a conductive material are dropped to form a conductive thin film, and this is used as a gate electrode, so that it can be cheaply and easily obtained. A ring-shaped gate electrode with a width on the order of submicron can be easily formed, and a plurality of gate electrodes corresponding to a plurality of thin film transistors can be easily formed.

In addition, the conductive thin film can be precipitated in a ring shape. By controlling the drying speed of the droplet containing the conductive material, the particle size, contact angle, and concentration of the conductive material, or by overlapping and arranging other droplets on the once-arranged droplet, etc. Shapes other than rings are precipitated, and which shape or control method to adopt is a matter of design.

A third aspect of the method for manufacturing a thin film transistor according to the present invention is characterized in that, in the manufactured thin film transistor, each gate electrode formed is electrically connected to at least one other gate electrode. In such a configuration, even when only one droplet is arranged, the droplet can be arranged such that the peripheral portion of the droplet faces a plurality of channel regions.

When there are two or more droplets arranged, at least a part of the peripheral portion of each droplet is opposed to one or more of the above-mentioned channel regions, and at least a part of the peripheral portion of each droplet is in contact with at least one of other droplets. The peripheral portions overlap each other, and each gate electrode is electrically connected to at least one other gate electrode.

With such a configuration, a multi-channel transistor in which a plurality of thin film transistors are connected in parallel can be obtained, and a plurality of transistors can be driven by a single gate signal.

In addition, in order to solve the above-mentioned third problem, the present invention provides a method of manufacturing a thin film transistor, which is a method of manufacturing two or more thin film transistors, the thin film transistor includes a semiconductor film including a channel region, and sandwiches the channel region. The opposite source region and drain region, and the gate electrode opposite to the above-mentioned channel region through the gate insulating film are characterized in that it includes: an arrangement process, by controlling the wettability of the surface of the gate insulating film, a droplet containing a conductive material is arranged so that at least a part of the periphery of each droplet is opposed to one or more of the channel regions; the deposition step is to form the gate electrode by depositing the conductive material only at the periphery of the droplet; the separation step is to separate Each gate electrode facing the channel region is formed in an island shape separated from the gate electrode facing the other channel region.

In this method, a plurality of gate electrodes corresponding to each of a plurality of thin film transistors can be easily formed by separating a conductive thin film formed by a closed-loop phenomenon to form a gate electrode, and at the same time, fine gate electrodes can be obtained at high density.

Preferably, the separation step is performed by, for example, removing a part of the precipitated gate electrode. The removal of the conductive thin film can be performed by, for example, a method of supplying an alkaline solvent to elute the thin film, and removing the conductive material for each solvent, or an etching method.

In addition, in the thin film transistor manufacturing method of the present invention, it is preferable that the manufactured thin film transistors each have one gate electrode, and a set of source regions and drain regions are formed for each gate electrode. With this structure, multi-connected transistors can be formed at high density. In addition, a structure in which a source region and/or a drain region is shared with other adjacent thin film transistors is also included in the present invention.

In addition, it is preferable to arrange the next droplet in the above-mentioned droplet arrangement step so as to overlap a part of the conductive material deposited on the periphery of the previously arranged droplet, and then disperse a part of the conductive material. By adopting such a configuration, it is possible to have a degree of freedom according to the shape of the deposited conductive thin film.

In addition, it is preferable that two or more droplets are arranged in the droplet arrangement step, and the conductive material is deposited on at least the peripheral portion of the droplet shape obtained when two or more droplets are fused in the deposition step. Thereby, a larger annular conductive thin film, a linear conductive thin film, and the like can be obtained.

In the manufacturing method of the thin film transistor of the present invention, it is preferable that the semiconductor film of each thin film transistor to be manufactured is formed in an island shape separated from the semiconductor film of other thin film transistors.

In addition, the method of manufacturing a thin film transistor according to the present invention preferably includes a step of forming a gate insulating film with a flat surface on each channel region before the droplet arrangement step. If the surface of the insulating film is flat, the liquid droplets will be uniformly wetted and spread at the time of disposing, and the shape of the liquid droplets can be easily controlled.

In addition, the second and third aspects of the thin film transistor manufacturing method of the present invention preferably include the step of forming a gate insulating film with a flat surface on each of the above-mentioned channel regions before the above-mentioned droplet disposing step, In the discharge step, droplets are placed on the gate insulating film.

The flat gate insulating film is, for example, a coating type insulating film. For example, when an SOG film is formed by spin coating on a substrate on which a semiconductor pattern is formed, an insulating film that is thin in a region with a semiconductor pattern and thick in a region without a semiconductor pattern can be formed to obtain an insulating film with a flat surface. The SOG film may be one layer, and the SOG film may be used as a planarization mechanism instead of the above-mentioned CMP or the like. On the other hand, when an insulating film is formed on a semiconductor film by sputtering, there is a step difference in the insulating film between the layered portion of the semiconductor film and the portion formed on the region without the semiconductor film, but in this case, chemical mechanical Formed by grinding (CMP) and etching etc.

If the surface of the gate insulating film is flat, the droplets will spread evenly when placed on the gate insulating film, so that the droplets can be easily arranged in a desired shape, and the gate electrode can be patterned with high precision.

In addition, the present invention also includes an electro-optical device including a thin film transistor manufactured by the thin film transistor manufacturing method of the present invention described above, and an electronic device including the thin film transistor.

Here, the electro-optical device is generally a device including the thin film transistor of the present invention that emits light by electricity or has an electro-optical element that changes the state of light from the outside, and includes self-emitting devices and devices that control the passage of light from the outside. For example, as an electro-optical element, there are liquid crystal elements, electrophoretic elements having a dispersion medium in which electrophoretic particles are dispersed, EL (electroluminescent) elements, and electron emitting elements that emit light from electrons generated by application of an electric field to a light-emitting plate. source matrix type display device, etc.

In addition, the so-called electronic equipment generally refers to an equipment equipped with the thin film transistor of the present invention that realizes a certain function, such as an electro-optical device and a memory. Its composition is not particularly limited, but may include, for example, IC cards, mobile phones, video recorders, personal computers, head-mounted displays, rear or front projection projectors, facsimile devices with display functions, and viewfinders for digital cameras. Devices, portable TVs, DSP devices, PDAs, electronic notebooks, electro-optical display boards, displays for advertising, etc.

In addition, the present invention also provides a method of manufacturing a semiconductor device using a semiconductor film formed on a substrate to form a semiconductor element, comprising: a step of disposing liquid droplets containing a semiconductor material on the substrate; and drying the liquid droplets to generate a closed-loop phenomenon , a step of depositing a semiconductor material in at least the peripheral portion of the droplet; and a step of forming a semiconductor film by removing the semiconductor material in the center portion of the droplet when depositing the semiconductor material in the center portion of the droplet. In this manufacturing method, a fine semiconductor film can be formed at high density with a simple process.

Description of drawings

FIG. 1 is an explanatory diagram of a semiconductor film device according to a first embodiment.

FIG. 2 is an explanatory diagram of a semiconductor film device according to the first embodiment.

Fig. 3 is a perspective view of an inkjet type discharge device.

Fig. 4 is a side sectional view of an inkjet head.

5 is an explanatory diagram of a semiconductor film device according to a second embodiment.

6 is an explanatory diagram of a semiconductor film device according to a second embodiment.

7 is an explanatory diagram of a semiconductor film device according to a third embodiment.

8 is an explanatory diagram of a semiconductor film device according to a third embodiment.

9 is an explanatory diagram of a semiconductor film device according to a fourth embodiment.

10 is an explanatory diagram of a semiconductor film device according to a fourth embodiment.

11 is an explanatory diagram of a semiconductor film device according to a fourth embodiment.

12 is an explanatory diagram of a semiconductor film device according to a fifth embodiment.

13 is an explanatory diagram of a semiconductor film device according to a fifth embodiment.

14 is an explanatory diagram of a semiconductor film device according to a sixth embodiment.

15 is an explanatory diagram of a semiconductor film device according to a sixth embodiment.

16 is an explanatory diagram of a semiconductor film device according to a seventh embodiment.

17 is an explanatory diagram of a semiconductor film device according to a seventh embodiment.

18 is an explanatory diagram of a semiconductor film device according to an eighth embodiment.

19 is an explanatory diagram of a semiconductor film device according to an eighth embodiment.

20 is an explanatory diagram of a method of manufacturing a semiconductor film device according to a ninth embodiment.

21 is an explanatory diagram of a method of manufacturing a semiconductor film device according to a ninth embodiment.

22 is an explanatory diagram of a method of manufacturing a semiconductor film device according to a ninth embodiment.

23 is an explanatory diagram of a semiconductor film device according to a tenth embodiment.

24 is an explanatory diagram of a semiconductor film device according to an eleventh embodiment.

25 is an explanatory diagram of a semiconductor film device according to an eleventh embodiment.

26 is a diagram showing an equivalent circuit of a semiconductor film device according to an eleventh embodiment.

FIG. 27 is a diagram for explaining a method of forming a gate electrode according to the eleventh embodiment.

28 is an explanatory diagram of a semiconductor film device according to a twelfth embodiment.

29 is a diagram showing an equivalent circuit of a semiconductor film device according to a twelfth embodiment.

30 is an explanatory diagram of a semiconductor film device according to a thirteenth embodiment.

FIG. 31 is a diagram for explaining a method of forming a gate electrode according to a thirteenth embodiment.

32 is an explanatory diagram of a semiconductor film device according to a fourteenth embodiment.

FIG. 33 is a diagram for explaining a method of forming a gate electrode according to a fourteenth embodiment.

FIG. 34 is a diagram showing an example of a connection state of an electro-optical device.

Fig. 35 is an explanatory diagram of various electronic devices constructed using electro-optical devices.

Fig. 36 is an explanatory diagram of various electronic devices constructed using electro-optical devices. In the picture:

10, 50-substrate, 12, 52, 72-insulating film, 14, 54-droplet, 16, 56, 74, 88-semiconductor film, 18, 58, 76-gate insulating film, 20, 62-gate electrode, 22, 78-source/drain area, 25, 80-source/drain electrode, 30-inkjet ejection device, 31-inkjet nozzle, 100-electro-optical device

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>

1 and 2 are explanatory views showing a semiconductor film manufacturing method according to a first embodiment of the thin film transistor manufacturing method of the present invention. The present embodiment is characterized in that droplets containing a semiconductor material are placed on an insulating substrate and dried to form a semiconductor film using a closed-loop phenomenon.

(Insulating film forming process)

FIG. 1(A) is a plan view of a substrate on which an insulating film 12 is formed. A cross-sectional view along line 2A-2A of this FIG. 2 is shown in FIG. 2(A). As shown in FIG. 2(A), an insulating film 12 is formed on a substrate 10 made of an insulating material such as glass. In this embodiment, a silicon oxide film is formed as the insulating film 12 . The silicon oxide film can be formed by, for example, plasma chemical vapor deposition (PECVD method), reduced pressure chemical vapor deposition method (LPCVD method), physical vapor phase volumetric method such as sputtering method, or the like. In addition, the SOG film can also be formed by a coating method. After film formation, if the surface is not completely flat, wet etching with hydrofluoric acid or CMP is used to planarize the surface. The SOG film formed by the spin coating method has a planarization effect, so the above-mentioned planarization step is unnecessary. As a result, the unevenness of the surface of the insulating film 12 is eliminated, and the liquid droplets wet and spread uniformly, so that liquid droplets of a desired shape can be easily arranged.

(droplet disposition process)

Next, as shown in FIG. 1(B), droplets 14 containing a semiconductor material are arranged on the insulating film 12 . A cross-sectional view taken along line 2B-2B in FIG. 2 is shown in FIG. 2(B).

As the semiconductor material, for example, an organic semiconductor material can be used. The organic semiconductor material can be dissolved in non-polar organic solvents such as toluene, xylene, and mesitylene, and can be disposed on the insulating film 12 as liquid droplets. Examples of organic semiconductor materials include low-molecular compounds such as naphthalene, anthracene, tetracene, pentacene, and hexacene, or hydroxydiazole derivatives (PBD), and hydroxydiazole dimer (OXD-8). , beryllium-benzoquinoline complex (Bebq), triphenylamine derivatives (MTDATA) and triarylamine derivatives, triazole derivatives, polyphenylene, polyalkylfluorene, polyalkylthiophene, (P3HT) , polyvinylpyrene, polyvinylnaphthalene, F8T2 (poly(9,9-dioctylfluorene-co-bithiophene)) and other polymer compounds, but are not limited thereto. Organic semiconductors can be processed at room temperature, do not require large-scale manufacturing equipment, and can be manufactured inexpensively. In addition, as the droplet containing the semiconductor film material, a liquid obtained by dissolving at least one silicon compound selected from the group consisting of cyclopentasilane and silylcyclopentasilane in an organic solvent such as xylene can be used. material to form an inorganic semiconductor film.

Methods of disposing the liquid droplets 14 on the insulating film 12 include methods using a micropipette, micro-spraying, and inkjet, but the inkjet method that can perform particularly accurate patterning is preferable. The inkjet method is performed using an inkjet type discharge device described later.

(Semiconductor material precipitation process)

As shown in Figure 1(B) and Figure 2(B), the droplet 14 arranged on the insulating film 12 dries faster in the peripheral part 15 than in the central part, and the semiconductor material on the peripheral part 15 reaches the saturation concentration first, and begins to precipitate . The peripheral portion of the droplet is pinned by the deposited semiconductor material, causing a "loop closure phenomenon" that suppresses shrinkage (shrinkage of outer diameter) of the droplet following subsequent drying. Due to the fast drying speed of the peripheral portion 15, liquid flow occurs from the center of the droplet to the peripheral portion 15, and the material on the semiconductor film is transported to the peripheral portion 15, forming a ring-shaped semiconductor film 16 that follows the shape of the droplet.

FIG. 1(C) shows a state where the droplet is completely dried, the material on the semiconductor film is deposited along the shape of the periphery of the droplet, and the semiconductor film 16 is formed. A cross-sectional view along line 2C-2C of this figure is shown in FIG. 2(C). The semiconductor film 16 is formed into a ring shape with a width of 1 μm or less.

When the droplet 14 dries, it can be controlled to increase the concentration of the semiconductor material in the peripheral portion of the droplet. For example, by adjusting the temperature of the substrate, or controlling the gasification state or viscosity of the droplets by spraying the droplets again on the temporarily dried semiconductor film, convection is generated in the droplets, and the semiconductor material can be efficiently moved to the peripheral portion 15 . In this way, the semiconductor material is concentrated in the peripheral portion of the droplet, which can more effectively prevent the semiconductor material from remaining in the central portion 17 of the semiconductor film 16, and can deposit a ring-shaped semiconductor film with a narrow width, so that it can be used directly without patterning. Formation of semiconductor elements.

The crystallinity of the obtained semiconductor film 16 can be improved by irradiating heat or light energy. For example, heat treatment by rapid thermal processing (RTP), or X-rays, ultraviolet rays, visible rays, infrared rays (heat rays), lasers, millimeter waves, microwaves, electron beams, radiation (α rays, β rays) as light energy can be mentioned. , γ-rays), etc., are particularly preferably lasers that can be irradiated with high output. Examples of laser light include various gas lasers and solid-state lasers (semiconductor lasers), among which excimer lasers, Nd-YAG lasers, Ar lasers, CO2 lasers, He-Ne lasers, and the like are suitable. Among them, an excimer laser having a wavelength of 350 nm or less in which the surface of a semiconductor film absorbs irradiation energy is particularly suitable.

(Element forming process)

Next, a process of forming a semiconductor element using the semiconductor film manufactured by the above-mentioned manufacturing method will be described by taking a thin film transistor as an example.

FIG. 1(D) and FIG. 2(D) show the state where the gate insulating film 18 and the gate electrode 20 are formed. FIG. 2(D) is a cross-sectional view along line 2D-2D of FIG. 1(D).

As shown in FIG. 2(D), a gate insulating film 18 and a gate electrode 20 are formed on the semiconductor film 16 . The gate insulating film 18 is, for example, a silicon oxide film, and the silicon oxide film can be formed by a film-forming method such as electron cyclotron resonance PECVD (ECR-PECVD), and an SOG film. The gate electrode 20 can be formed by patterning after forming a conductive thin film such as tantalum or aluminum by a film-forming method such as sputtering.

In FIG. 1(D), the gate insulating film 18 is omitted to show the positional relationship between the semiconductor film 16 and the gate electrode 20 . The gate electrode 20 is arranged across the annular semiconductor film 16 .

Next, impurity elements serving as donors and acceptors are implanted using the gate electrode 20 as a mask to perform so-called self-matching ion implantation to form source/drain regions 22 and channel regions 23 on the semiconductor film 16 . For example, phosphorus (P) is implanted as an impurity element, and then the XeCl excimer laser is irradiated with an energy density of 400mJ/cm2 to activate the impurity element, thereby forming an N-type source/drain region. In addition, instead of laser irradiation, impurity elements may be activated by heat treatment at about 250° C. to 400° C.

Next, as shown in FIGS. 1(E) and 2(E), the steps of forming an interlayer insulating film and source/drain electrodes are shown. FIG. 2(E) is a cross-sectional view along line 2E-2E of FIG. 1(E). And, as shown in 2(E), an interlayer insulating film 24 made of a silicon oxide film is formed to cover the gate insulating film 18 and the gate electrode 20 . The silicon oxide film is formed to a thickness of about 500 nm by, for example, a film forming method such as PECVD method or SOG method. Next, contact holes across the source/drain region 22 are formed through the gate insulating film 18 and the interlayer insulating film 24, and conductors such as aluminum or tungsten are embedded in these contact holes by a film-forming method such as sputtering and then patterned, thereby Source/drain electrodes 25 are formed. This forms a thin film transistor.

In FIG. 1(E), in order to clarify the positional relationship of the source/drain region 22, the gate electrode 20, the source/drain electrode 25, etc., the gate insulating film and the interlayer insulating film are omitted. In the ring-shaped semiconductor film, the part where the gate electrode is not laminated is the source/drain region 22, and the part where the gate electrode is laminated is the channel region, forming a thin film transistor. Source/drain electrodes are formed at the center of the source/drain regions.

Thus, in the present embodiment, a semiconductor film of a predetermined shape can be formed by simple steps of disposing a liquid containing a semiconductor material and drying it, and the insulating film forming process can be continuously performed without patterning the semiconductor film.

(droplet ejection device)

Each of the droplets described above is formed by ejecting a liquid from an inkjet type ejection device. Therefore, an inkjet type discharge device will be described using FIG. 3 . FIG. 3 is a perspective view of an inkjet discharge device 30 . The inkjet discharge device 30 is mainly composed of a base 32 , a first moving member 34 , a second moving member 36 , an electronic balance (not shown) as a weight measuring member, a head 31 , a capping unit 33 and a cleaning unit 35 . The operation of the inkjet discharge device 30 including the first moving member 34 and the second moving member 36 is controlled by a control device. In FIG. 3 , the X direction is the left-right direction of the base 32 , the Y direction is the front-rear direction, and the Z direction is the up-down direction.

The first moving member 34 is provided directly on the upper surface of the base 32 so that the two guide rails 38 are aligned with the Y-axis direction. The first moving member 34 has a slider 39 movable along two guide rails 38 . As the driving means of the slider 39, for example, a linear motor can be used. Accordingly, the slider 39 can move in the Y-axis direction and can be positioned at any position.

The motor 37 is fixed on the slider 39 , and a table 46 is fixed on the rotor of the motor 37 . The stage 46 holds and positions the substrate 10 . That is, the substrate 10 can be held on the table 46 by suctioning the substrate 10 through the hole 46A of the table 46 by operating a suction holding member not shown. In addition, the motor 37 is, for example, a direct drive motor. By energizing the motor 37, the table 46 rotates in the θz direction together with the rotor, and a preliminary discharge area where the head 31 throws off the liquid or tries to discharge (preliminary discharge) is provided on the table 46.

On the other hand, two pillars 36A are erected behind the base 32, and a pillar 36B is bridged over the upper ends of the pillars 36A. And the second moving member 36 is provided on the entire surface of the column 36B. The second moving member 36 has two guide rails 84A arranged along the X-axis direction, and has a slider 82 movable along the guide rails 84A. As the slider 82 driving means, for example, a linear motor can be used. Accordingly, the slider 82 can move in the X-axis direction and can be positioned at an arbitrary position.

The slider 82 is provided with the head 31 . The head 31 is connected with motors 84, 85, 86, 87 as rocking positioning components. The motor 84 can move the head 31 in the Z-axis direction, and can be positioned at any position. The motor 85 can oscillate the head 31 in the β direction around the Y axis, and can be positioned at any position. The motor 86 can oscillate the head 31 in the γ direction around the X-axis, and can be positioned at any position. The motor 87 can oscillate the head 31 in the α direction around the Z axis, and can be positioned at any position.

As described above, the substrate 10 can be moved and positioned in the Y direction, and can be moved and positioned in the θz direction. The head 31 can be moved and positioned in the X and Z directions, and can be swung and positioned in the α, β, and γ directions. Therefore, the inkjet discharge device 30 of the present embodiment can accurately control the relative position and posture of the ink discharge surface 31P of the head 31 and the substrate 10 on the stage.

(inkjet head)

Here, the configuration of the head 31 will be described with reference to FIG. 4 . Fig. 4 is a side sectional view of an inkjet head. The head 31 ejects the liquid L from the nozzles 41 by a droplet ejection method. As the liquid droplet ejection method, various known techniques such as a piezoelectric method for ejecting liquid using a piezoelectric element as a piezoelectric element, and a method for ejecting liquid by heating bubbles (bubbles) generated by liquid can be applied. Among them, the piezoelectric method does not heat the liquid, so there is an advantage that it does not affect the composition of the material. The head 31 of FIG. 4 adopts a piezoelectric method.

A reservoir 45 and a plurality of ink chambers 43 branched from the reservoir 45 are formed on the head main body 40 of the head 31 . The reservoir 45 serves as a flow path for supplying the liquid L to each ink chamber 43 . In addition, a nozzle plate constituting an ink ejection surface is attached to the lower end surface of the head main body 40 . On the nozzle plate, a plurality of nozzles 41 for ejecting liquid L are opened corresponding to the respective ink chambers 43 . In addition, an ink flow path is formed from each ink chamber 43 toward the corresponding nozzle 41 . On the other hand, a vibrating plate 44 is attached to the upper end surface of the head main body 40 . The vibrating plate 44 forms the wall surface of each ink chamber 43 . A piezoelectric element 42 is provided on the outside of the vibrating plate 44 corresponding to each ink chamber 43 . The piezoelectric element 42 sandwiches a piezoelectric material such as crystal with a pair of electrodes (not shown). The pair of electrodes is connected to the drive circuit 49 .

Further, when a voltage is applied from the driving circuit 49 to the piezoelectric element 42 , the piezoelectric element 42 expands and deforms or contracts. When the piezoelectric element 42 shrinks and deforms, the pressure of the ink chamber 43 decreases, and the liquid L flows from the reservoir 45 into the ink chamber 43 . In addition, the pressure of the piezoelectric element 42 decreases, and the liquid L flows from the reservoir 45 into the ink chamber 43 . When the piezoelectric element 42 expands and deforms, the pressure of the ink chamber 43 increases, and the liquid L is ejected from the nozzle 41 . In addition, the deformation speed of the piezoelectric element 42 can be controlled by changing the frequency of the applied voltage. That is, the discharge condition of the liquid L is controlled by controlling the voltage applied to the piezoelectric element 42 .

On the other hand, the inkjet discharge device shown in FIG. 3 includes a capping unit 33 and a cleaning unit 35 . The capping unit 33 is used to prevent the ink ejection surface 31P of the head 31 from drying out, and caps the ink ejection surface 31P when the inkjet discharge device 30 is on standby. The cleaning unit 35 is a component for removing deposits on the nozzles of the head 31 to suck inside the nozzles. The cleaning unit 35 wipes the ink ejection surface 31P of the head 31 to remove contamination on the ink ejection surface 31P.

<Second Embodiment>

5 and 6 show a method of manufacturing a semiconductor film according to a second embodiment of the present invention. In this embodiment mode, a thin film transistor is also used as an example for description. The present embodiment is characterized in that the gate electrode is also formed by disposing and drying a liquid containing a conductive material in addition to the semiconductor film.

(Semiconductor film formation process)

First, as shown in FIGS. 5(A) and (B), droplets 54 containing a semiconductor material are placed on an insulating film 52 and dried to obtain a semiconductor film 56 . The sectional views of the 6A-6A line and the 6B-6B line in the two figures are shown in Fig. 6(A) and (B). The insulating film 52 is laminated on the substrate 50 such as a glass substrate. The insulating film forming step, the droplet arrangement step, and the semiconductor material deposition step are performed by the same method as in the first embodiment, and description thereof is omitted.

(Gate electrode formation process)

Next, a process of forming a gate electrode for a semiconductor element using the semiconductor film produced by the above-mentioned production method will be described with reference to FIGS. 5(C)(D) and 6(B') to (D). The sectional views of the 6C-6C line and the 6D-6D line of Fig. 5 are Fig. 6 (C) and (D ) respectively. In FIG. 5 , the gate insulating film 58 is omitted to show the positional relationship between the semiconductor film and the gate electrode.

First, the step of forming the gate insulating film 58 on the semiconductor film 56 is shown using FIG. 6(B'). The gate insulating film 58 may be, for example, a silicon oxide film, and the silicon oxide film may be formed by, for example, an electron cyclotron resonance PECVD method (ECR-PECVD method). As shown in FIG. 6(B), in the gate insulating film 58 formed in this way, a step difference occurs between the region stacked on the semiconductor film 56 and other regions. When the gate insulating film 58 is uneven, the surface is flattened. As a planarization method, for example, a CMP method or an etch-back method is used. In this way, the liquid droplets containing the conductive material wet and spread on the gate insulating film 58 more uniformly, and the shape of the liquid droplets can be easily controlled. In addition, when an SOG film is used for the gate insulating film, the SOG film automatically absorbs the level difference of the semiconductor film 56, and a flat surface of the gate insulating film can be obtained.

Next, as shown in FIGS. 5(C) and 6(C), droplets 60 containing a gate electrode material are disposed on the gate insulating film 58 . The gate electrode material is preferably conductive fine particles such as Ag, Au, Cu, etc., having a diameter of about several nm. These fine particles are dispersed in an organic dispersant such as water or tetradecane, and are arranged as droplets on the gate insulating film 58 using an inkjet method or the like.

As shown in FIGS. 5(D) and 6(D), when the droplet 60 is dried, the gate electrode material begins to precipitate from the periphery of the droplet, and a ring-shaped gate electrode 62 following the shape of the droplet is obtained. A part of the gate electrode 62 is arranged across the semiconductor film 56 . In order not to leave the conductive material in the center of the droplet, it is possible to positively control the gate electrode material to concentrate on the periphery of the droplet. As for the control method, the same method as that of the above-mentioned semiconductor film is used, and the description thereof is omitted here.

(Element forming process)

Next, using the gate electrode 62 as a mask, impurity elements serving as donors and acceptors are implanted to form source/drain regions on the semiconductor film 56 . Next, an interlayer insulating film is formed to cover the gate insulating film 58 and the gate electrode 62, a contact hole is formed through the gate insulating film and the interlayer insulating film, and source/drain electrodes are formed by embedding conductors in the contact hole. These steps are performed in the same manner as those of the above-mentioned first embodiment, and description thereof is omitted.

According to the method of this embodiment, not only the semiconductor film but also the gate electrode can be formed in a short time through simple steps of droplet arrangement and drying. The gate electrode can be formed with a width of less than 1 micron, and using it as a mask to implant impurities to form source/drain regions, so that a thin film transistor with a gate length of less than 1 micron can be obtained. By shortening the gate length, the gate capacitance can be reduced, thereby forming a high-performance thin film transistor.

<Third Embodiment>

FIG. 7 shows an outline of a method of manufacturing a semiconductor film according to a third embodiment. In this embodiment, two thin film transistors are produced from one semiconductor film obtained by disposing and drying droplets.

First, as shown in FIG. 7(A), a semiconductor film 74 is formed on an insulating film 72 in the same manner as in the first and second embodiments. Next, as shown in (B) of the figure, a part of the semiconductor film is removed to obtain semiconductor films 74a and 74b. In order to remove a part of the semiconductor film 74, for example, a method of adding the above-mentioned droplet of solvent to the place to be removed, eluting the semiconductor material and removing it for each solvent, or an etching method is used. The area to be removed does not require sub-micron precision for relatively large areas, so etching can be used, which is not particularly high-precision, but is a cheap and common method.

Next, a gate insulating film (not shown) is formed to cover the semiconductor film 74, and then gate electrodes 76a and 76b are formed across the respective centers of the semiconductor films 74a and 74b. The gate electrode is formed by placing a droplet containing a gate electrode material on the gate insulating film, drying it, and forming it by a closed-loop phenomenon. Conductor thin films may be formed by sputtering or the like, or may be formed by patterning, but a gate electrode having a width on the submicron order is easily formed due to the loop closure phenomenon. The patterning of the gate electrode can be carried out by a method of supplying an acidic droplet to elute the electrode and an etching method. In this case, the removal process does not require submicron precision, so etching is used, which is not a particularly high-precision method but is an inexpensive and commonly used method.

Next, impurity elements serving as donors and acceptors are implanted using the gate electrodes 76a and 76b as masks to form source/drain regions 78a to 78d. Next, an interlayer insulating film (not shown) is formed to cover the gate electrodes 76a, 76b and the gate insulating film (not shown), and a contact hole is formed through the gate insulating film and the interlayer insulating film. body to form source/drain electrodes 80a to 80d. These steps are performed in the same manner as those of the above-mentioned first embodiment, and description thereof is omitted.

According to the method of this embodiment, two semiconductor films used for semiconductor elements can be obtained in a simple process, and semiconductor devices can be manufactured with high density and high efficiency. In addition, the gate electrode is also manufactured through the closed-loop phenomenon, the manufacturing process is simpler, and at the same time, a semiconductor device with a gate length of less than 1 micron is obtained. In addition, in this embodiment, two semiconductor films are formed, but three or more semiconductor films may be formed.

In addition, in the above-mentioned first to third embodiments, only one droplet containing a semiconductor material or a gate electrode material was placed and dried to obtain a ring-shaped thin film, but a plurality of droplets may be placed.

FIG. 8 is an explanatory diagram illustrating a case where two or more liquid droplets are arranged to form a thin film. As shown in FIG. 6(A), when droplets containing a semiconductor material are arranged at a certain interval, as shown in the figure (B), the droplets are wetted and spread, and the droplets are fused, as shown in the figure (C). Become a linear droplet. The ring-closing phenomenon is caused by drying the linear droplet, and a ring-shaped thin film along the outer periphery of the linear droplet is obtained as shown in the figure (D). In this way, a linear semiconductor film 88 can be obtained. In addition, in the present embodiment, if each droplet is arranged to overlap a part of each droplet, two or more droplets will be fused by wetting and spreading of each droplet. Thereby, the shape of the droplet can be changed in various ways, and the degree of freedom in the shape of the obtained semiconductor thin film can be improved. For example, linear droplets can be obtained by linearly juxtaposing and fusing multiple droplets. When the closed loop is caused by the linear droplet and the semiconductor material is precipitated at the periphery thereof, a linear semiconductor film having a width on the order of submicron can be obtained. In addition to fusing all the droplets into one large droplet, it is also possible to obtain a linear semiconductor film by repeatedly fusing two or more droplets and depositing a semiconductor film on the periphery thereof.

<Fourth Embodiment>

9 and 10 are explanatory diagrams showing a method of manufacturing the thin film transistor according to the first embodiment of the present invention. The thin film transistor manufactured in this embodiment mode is a top-gate thin film transistor T shown in FIG. 11(B). The thin film transistor T includes a channel region 424 provided on a semiconductor film, a source/drain region 424 corresponding to the channel region 424 , and a gate electrode 420 opposed to the channel region 424 via a gate insulating film 416 .

(Semiconductor film formation process)

FIG. 9(A) shows a state where a semiconductor film 414 is formed on an insulating film 412 formed on a substrate 410 . The insulating film 412 is formed on the substrate 410 made of an insulating material such as glass. In this embodiment mode, a silicon oxide film is formed as the insulating film 412 . The silicon oxide film can be formed by, for example, plasma chemical vapor deposition (PECVD), reduced pressure chemical vapor deposition (LPCVD), physical vapor deposition such as sputtering, or the like. In addition, a liquid material can be used as a coating type insulating film (SOG film).

In this embodiment mode, a silicon film is formed as the semiconductor film 414 . The silicon film is formed by a CVD method such as APCVD method, LPCVD method, or PECVD method, or a PVD method such as a sputtering method or a vapor deposition method. Alternatively, the silicon film may be formed using the closed-loop phenomenon in the same manner as the method for forming the gate electrode used in the manufacturing method of the thin film transistor of the present invention described above.

When using the closed-loop phenomenon, a droplet containing a silicon material is placed such that the peripheral portion of the droplet is located in a region where the silicon film is formed. Furthermore, a plurality of liquid droplets containing a silicon material may be arranged according to the shape of the silicon film, and the silicon film may be deposited at the peripheral portion of the droplet shape obtained when these droplets fuse. In addition, similar to the method for forming the gate insulating film of the present invention, a step of increasing the concentration of the silicon film material in the peripheral portion of the droplet, a step of removing a part of the silicon film after formation, and applying heat or light energy to the formed semiconductor film can be performed. Process for improving crystallinity.

In the case of forming a silicon film by LPCVD, the substrate temperature is about 400°C to 700°C, and silicon is deposited at a substrate temperature of about 100°C to about 500°C using disilane (Si2H6) or the like as a raw material. When using the sputtering method, the substrate temperature is from room temperature to about 400°C. In this way, the initial state of the deposited silicon film is mostly in various states such as amorphous, mixed crystal, microcrystalline, or polycrystalline, but it may be in any state. The film thickness of the silicon film is appropriately about 20 nm to 100 nm when used in a semiconductor film transistor. The deposited semiconductor film is crystallized by supplying thermal energy. In the present specification, the term "crystallization" includes not only the crystallization of amorphous semiconductor films but also the crystallization of polycrystalline and microcrystalline semiconductor films. For crystallization of the semiconductor film, laser irradiation method and solid phase growth method can be used, but not limited thereto.

(Insulating film forming process)

The process of forming the gate insulating film 416 will be described with reference to FIGS. 9(B) and (C). A gate insulating film 416, such as a silicon oxide film, is formed to cover the semiconductor film 414 and the insulating film 412. The silicon oxide film can be formed by, for example, electron cyclotron resonance PECVD (ECR-PECVD), PECVD, atmospheric pressure chemical vapor deposition (APCVD), or low pressure chemical vapor deposition (LPCVD). In the gate insulating film 416 formed in this way, as shown in FIG. 1(B), a step difference occurs between the region laminated on the semiconductor film 414 and the region laminated on the insulating film 412, and the plane thereof is uneven. When a droplet containing a conductive material is supplied thereon, it cannot spread uniformly by wetting, and the conductive material cannot be deposited at a desired position to obtain a gate electrode. Therefore, as shown in FIG. 9(C), the gate insulating film 416 is planarized before disposing the liquid droplets containing the conductive material. Planarization can be performed by chemical mechanical polishing (CMP), or etching.

The gate insulating film can also be formed by coating a liquid high-K material and SOG using spin coating. In the case of coating from a liquid material, a flat surface is obtained only through the coating process, so it is not necessary to perform flattening after the insulating film is formed. A film formed by spin coating may be laminated on a gate insulating film formed by PECVD or the like. The surface can be planarized by laminating the film by spin coating.

(droplet disposition process)

Next, as shown in FIG. 9(D), droplets 418 containing a conductive material are arranged on the insulating film 416 . As the conductive material, metal microparticles such as Ag, Au, Cu, and Ni having a diameter of about a few nm can be used, and Ag colloidal ink, for example, is suitable. These fine metal particles are dispersed in an organic dispersant such as tetradecane and supplied as liquid droplets.

Methods of arranging the liquid droplets 418 on the insulating film 416 include methods using a microdropper, microsprinkling, and inkjet, but the inkjet method that can perform particularly accurate patterning is suitable. The inkjet method is performed using an inkjet type discharge device described later.

FIG. 10(A) is a plan view showing a droplet arrangement step. The cross-sectional view along the line LCD-LCD in FIG. 10(A) is FIG. 9(D). In FIG. 10(A), the gate insulating film 416 is omitted to clarify the positional relationship between the semiconductor film 414 and the droplet 418 . The droplet 418 is arranged such that its peripheral portion faces the channel region, and a part of its outer peripheral arc traverses the vicinity of the center of the semiconductor film 414 .

When arranging the droplets, by controlling the wettability of the surface of the gate insulating film 416 , the peripheral portion of the droplet 418 is arranged to face the channel region, that is, the peripheral portion of the droplet 418 crosses near the center of the semiconductor film 414 . Wettability control is performed by forming a monomolecular film on the surface of the gate insulating film using, for example, a compound having a functional group that forms SAMs on the surface of the gate insulating film and a functional group that has a lyophobic property at the other end. By forming such a SAM film, except for the area where the gate electrode is formed, the liquid droplets containing the conductive material move to the portion where the SAM film is not formed, where the conductive material is dried and deposited.

(Conductive material precipitation process)

In the droplet 418 arranged on the insulating film 416, the above-mentioned closed-loop phenomenon occurs, and a ring-shaped conductive film 420 is formed that follows the shape of the droplet.

FIG. 9(E) shows a state in which the droplet is completely dried, the conductive material is deposited along the shape of the periphery of the droplet, and a ring-shaped conductive film 420 is formed. FIG. 10(B) is a plan view showing a conductive material deposition step. A cross-sectional view along line IXE-IXE in FIG. 10(B) is shown in FIG. 9(E). The conductive film 420 is formed in a ring shape with a width of 1 μm or less, and is arranged across the approximate center of the semiconductor film 414 .

In addition, when the droplet 418 dries, it can be controlled to increase the concentration of the conductive material in the periphery of the droplet. For example, adjusting the temperature of the insulating substrate, or controlling the gasification state or viscosity of the droplets by re-spraying the droplets on the temporarily dried conductive film, convection is generated in the droplets, and the conductive material can be efficiently moved to the peripheral department. In this way, the conductive material does not remain in the central portion of the conductive film 420, and the conductive material can be deposited in a narrow ring shape. After the electroconductive material is deposited, heat treatment can be performed on the obtained electroconductive film to agglomerate metal fine particles, thereby improving the electroconductivity of the film.

(Source/drain region formation process))

Next, as shown in FIG. 11(A), impurity elements that become donors and acceptors are implanted using the gate electrode 420 as a mask to perform so-called self-matching ion implantation, thereby forming source/drain regions 422 and active regions on the semiconductor film 414. 424. For example, phosphorus (P) is implanted as an impurity element, and then the XeCl excimer laser is adjusted to an energy density of about 400mJ/cm2 for irradiation to activate the impurity element, thereby forming an N-type thin film transistor. In addition, instead of laser irradiation, impurity elements may be activated by heat treatment at about 250° C. to 400° C.

As mentioned above, the width of the gate electrode 20 is less than 1 micron, so by using it as a mask to form source/drain regions, a semiconductor element with a gate length of sub-micron order can be obtained.

Thus, in the present embodiment, a conductive film having a width on the order of submicrometers can be formed into a desired shape by a simple process of disposing a liquid containing a conductive material and drying it, without patterning the conductive film. used as the gate electrode. According to this configuration, it is possible to easily and inexpensively form a high-performance and high-integration semiconductor element with a very short gate length, which is suitable.

(droplet ejection device)

Each of the above-mentioned droplets is formed by being ejected from an inkjet type discharge device. The configurations of the inkjet type discharge device and the inkjet head were described in the first embodiment using FIGS. 3 and 4 , and the description is omitted here.

<Fifth Embodiment>

FIG. 12 and FIG. 13 show a thin film transistor according to a second embodiment of the present invention. FIG. 13 is a cross-sectional view along line XIII-XIII of FIG. 12 .

As shown in FIG. 13 , in the thin film transistor of the present embodiment, two gate electrodes 463a and 463b are formed between source/drain regions 464a and 464b, so-called "dual-gate transistors". A transistor having such a structure has a feature of so-called low leakage current, and functions as a single transistor as a whole. As can be seen from FIGS. 12 and 13 , the gate electrodes 463 a and 463 b are part of one ring-shaped conductive thin film 463 .

This semiconductor device is formed by arranging a droplet containing a conductive material so that its peripheral portion reaches the position where the gate electrode 463 is to be formed in the thin film transistor manufacturing method of the present invention described above. Alternatively, the droplet shrinkage during drying may be observed, and the droplet containing the conductive material may be placed at a position larger than the position where the gate electrode 463 should be formed. For example, liquid droplets are arranged in the semiconductor film 464 so as to cover the remaining portion from both ends of the semiconductor film except the regions where the source/drain regions 464a and 464b are to be formed.

In this manner, two gate electrodes can be formed at desired positions by an easy and inexpensive process of arranging one droplet of conductive material and drying it. The resulting gate electrode can be sub-micron in width, so there is no need for patterning thereafter, and the gate capacitance of the semiconductor device can also be reduced. When the number of gates increases, the current also increases and its performance improves. When the same amount of current flows, the current per gate is very small, so that current loss and heat generation can be suppressed.

In addition, as the fifth embodiment, a double gate type in which two gate electrodes are formed for one source/drain region has been described as an example, but using the method for forming gate electrodes of the present invention, three gate electrodes can be formed for one source/drain region. The above gate electrodes constitute a multi-gate transistor, which is also included in the present invention.

<Sixth Embodiment>

14 and 15 show a semiconductor device according to a sixth embodiment of the present invention. FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 14 .

The semiconductor device of this embodiment includes a double-connected thin film transistor composed of two semiconductor elements including a semiconductor element including source/drain regions 472a and 472b and a semiconductor element including source/drain regions 472c and 472d. Each of the gate electrodes 474a and 474b of the double-connected thin film transistor shown in FIG. 15 is a part of one annular conductive thin film 474 shown in FIG. 14 . This double-connected transistor can be regarded as two transistors connected in parallel, and as a whole, it functions as one transistor with a large gate width (or channel width).

This semiconductor device is formed by arranging a droplet containing a conductive material at a position where the conductive thin film 474 is to be formed, that is, a position facing the channel region in the thin film transistor manufacturing method of the present invention described above. Alternatively, the droplet containing the conductive material may be placed at a position larger than the position where the gate electrode 474 should be formed by observing the shrinkage of the droplet during the drying process. For example, liquid droplets are arranged in the semiconductor film 472 so as to cover the remaining portion from both ends of the semiconductor film except the regions where the drain regions 472a and 472b are to be formed.

In this way, two gate electrodes for a double-connected thin film transistor can be formed at desired positions by an easy and inexpensive process of disposing a droplet of a conductive material and drying it. The resulting gate electrode can be sub-micron in width, so there is no need for patterning thereafter, and the gate capacitance of the semiconductor device can also be reduced. Double-connected thin film transistors can be easily formed, and microfabrication and high-density semiconductor elements can also be easily performed.

<Seventh embodiment>

A semiconductor device according to a seventh embodiment of the present invention is shown in FIGS. 16 and 17 . FIG. 17 is a cross-sectional view along line XVII-XVII of FIG. 16 .

The semiconductor device of this embodiment includes a double-connected thin film transistor composed of two semiconductor elements including a semiconductor element including drain/source regions 484a and 484b and a semiconductor element including source/drain regions 484c and 484d. As shown in FIG. 16, each of the gate electrodes 486a and 486b of the double-connected thin film transistor shown in FIG. 17 is formed by removing a part of one annular conductive thin film. This double-connected transistor is considered to have a common source for two transistors performing different operations.

This semiconductor device is formed by arranging liquid droplets containing a conductive material at positions where the conductive thin films 486a and 486b are to be formed in the thin film transistor manufacturing method of the present invention described above. Alternatively, the droplet containing the conductive material is arranged to have a larger diameter than the circles on which the conductive thin films 486a and 486b are to be formed, observing the shrinkage of the droplets during the drying process. For example, liquid droplets may be arranged in the semiconductor film 484 so as to cover the remaining portion from both ends of the semiconductor film except the regions where the source/drain regions 484a and 484b are to be formed. Next, after depositing a conductive material in a drying step, the thin film at the unnecessary portion of the gate electrode is removed to obtain gate electrodes 486a and 486b. As a thin film removal method, a method of supplying an acidic solution such as hydrochloric acid or sulfuric acid and removing the acidic solution together with an unnecessary conductive thin film, a method of peeling off a silicon oxide film with hydrofluoric acid, or an etching method can be used. The area of the removed film is not on the order of submicron, so etching is a relatively inexpensive general method.

According to the present embodiment, two gate electrodes for a double-connected thin film transistor can be formed at desired positions by an easy and inexpensive process of arranging and drying one droplet of a conductive material. The resulting gate electrode can be sub-micron in width, so there is no need for patterning thereafter, and the gate capacitance of the semiconductor device can also be reduced. Double-connected thin film transistors can be easily formed, and microfabrication and high-density semiconductor elements can also be easily performed.

<Eighth Embodiment>

A semiconductor device according to a fifth embodiment of the present invention is shown in FIGS. 18 and 19 . FIG. 19 is a cross-sectional view taken along line XIX-XIX of FIG. 18 .

As shown in FIG. 19 , the semiconductor device of the present embodiment is a complementary MOS semiconductor device including an N-channel MOS transistor _TN and a P-channel MOS transistor T _P. The drain/source regions (492a and 492b) and the source/drain regions (492c and 492d) have different conductivity types, and the electrode 496b is electrically connected to both the P part and the N part.

The respective gate electrodes 494a and 494b of the N-channel type MOS transistor and the P-channel type MOS transistor form part of a conductive annular film 494, as shown in FIG.

In this semiconductor device, in the manufacturing process of the complementary MOS semiconductor device, when forming the gate electrode, the gate electrode of the N-channel MOS transistor _TN and the P-channel MOS transistor T _P should be formed. Droplets of conductive materials are dried to precipitate conductive materials.

According to the present embodiment, the gate electrode of the double transistor can be formed by a simple process of disposing one droplet and drying it. The resulting gate electrode can be sub-micron in width, so there is no need for patterning thereafter, and the gate capacitance of the semiconductor device can also be reduced.

<Ninth Embodiment>

20 and 21 are explanatory diagrams showing a method of manufacturing a gate electrode according to a ninth embodiment of the present invention. This embodiment mode shows a method of manufacturing a multi-channel thin film transistor including two thin film transistors using the thin film transistor manufacturing method of the present invention.

(Semiconductor film formation process)

FIG. 20(A) shows a state where a semiconductor film 514 is formed on an insulating film 512 formed on a substrate 510 . The insulating film 512 is formed on the substrate 510 made of an insulating material such as glass. In this embodiment mode, a silicon oxide film is formed as the insulating film 512 . The silicon oxide film can be formed by, for example, plasma chemical vapor deposition (PECVD), reduced pressure chemical vapor deposition (LPCVD), physical vapor deposition such as sputtering, SOG (spin on glass) or the like.

In this embodiment mode, a silicon film is formed as the semiconductor film 514 . The silicon film is formed by a CVD method such as APCVD method, LPCVD method, or PECVD method, or a PVD method such as a sputtering method or a vapor deposition method. In the case of forming a silicon film by LPCVD, the substrate temperature is set at about 400°C to 700°C, and silicon is deposited using silane (SiH4), disilane (Si2H6) or the like as a raw material. In the PECVD method, silicon can be deposited at a substrate temperature of about 100° C. to 500° C. using silane (SiH4) as a raw material. In this way, the initial state of the deposited silicon film has various states such as amorphous, mixed crystal, microcrystalline, or polycrystalline, but any state may be used. The thickness of the silicon film is appropriately about 20 nm to 100 nm when used in a semiconductor film transistor. The deposited semiconductor film is crystallized by supplying thermal energy. In the present specification, the term "crystallization" includes not only the crystallization of amorphous semiconductor films but also the crystallization of polycrystalline and microcrystalline semiconductor films. The crystallization of the semiconductor film can use a laser irradiation method and a solid-phase growth method, but is not limited thereto.

Next, the formed semiconductor film is patterned into a desired shape by etching using photolithography to obtain a silicon film 514 .

(Insulating film forming process)

The process of forming the gate insulating film 516 will be described with reference to FIGS. 20(B) and (C). A gate insulating film 516, such as a silicon oxide film, is formed to cover the semiconductor film 514 and the insulating film 512. The silicon oxide film can be formed by, for example, electron cyclotron resonance PECVD (ECR-PECVD), PECVD, atmospheric pressure chemical vapor deposition (APCVD), low pressure chemical vapor deposition (LPCVD), and the like. In the gate insulating film 516 formed in this way, as shown in FIG. 20(B), there is a step difference between the region stacked on the semiconductor film 514 and the portion stacked on the insulating film 512, and the plane thereof is uneven. When a droplet containing a conductive material is supplied thereon, it cannot spread uniformly by wetting, and the conductive material cannot be deposited at a desired position to obtain a gate electrode. Therefore, as shown in FIG. 20(C), the gate insulating film 516 is planarized before disposing the liquid droplets containing the conductive material. Planarization can be performed by chemical mechanical polishing (CMP) or etching.

The gate insulating film can also be formed by coating a liquid SOG material and a low-K material using spin coating. In the case of liquid material coating, even a base having a pattern or a step can be formed with a flat surface, so it does not need to be planarized after the insulating film is formed.

(droplet disposition process)

Next, as shown in FIG. 20(D), a droplet 518 containing a conductive material is placed on the insulating film 516 . As the conductive material, for example, metal microparticles such as Ag, Au, and Cu having a diameter of several nanometers can be used, and Ag colloidal ink, for example, is suitable. These fine metal particles are dispersed in an organic dispersant such as tetradecane and supplied as liquid droplets.

Methods of disposing the liquid droplets 518 on the insulating film 516 include methods using a microdropper, microsprinkling, and inkjet, but the inkjet method that can perform particularly accurate patterning is suitable. The inkjet method is performed using an inkjet type discharge device described later.

Fig. 21(A) is a plan view showing a droplet arrangement step. The cross-sectional view taken along line XXD-XXD in FIG. 21(A) is FIG. 20(D). In FIG. 21(A), the gate insulating film 516 is omitted to clarify the positional relationship between the semiconductor film 514 and the droplet 518 .

In this embodiment, two thin film transistors are formed using the semiconductor film 514, and the gate electrodes of the two thin film transistors are connected. The droplet 518 is arranged such that the peripheral portion of the droplet 518 crosses the semiconductor film 514 twice. More specifically, the diameter of the droplet 518 is the distance between the positions where the gate electrodes of two thin film transistors should be formed. Or to observe the shrinkage of the droplet during drying, set a droplet with a diameter slightly larger than this distance.

(Conductive material precipitation process)

In the droplet 518 arranged on the insulating film 516, the above-mentioned closed-loop phenomenon occurs, and the ring-shaped conductive film 520 following the outer shape of the droplet 518 is formed.

FIG. 20(E) shows a state where the droplet is completely dried, the conductive material is deposited along the shape of the droplet, and the ring-shaped conductive film 520 is formed. Fig. 21(B) is a plan view showing a conductive material deposition step. A cross-sectional view along line XXE-XXE in FIG. 21(B) is FIG. 20(E). The conductive film 520 is formed in a ring shape with a width of 1 μm or less, and is arranged to cross the semiconductor film 514 twice.

When the droplet 518 dries, it can be controlled to increase the concentration of the conductive material in the periphery of the droplet. For example, adjusting the temperature of the insulating substrate, or controlling the gasification state and viscosity of the droplets by re-spraying the droplets on the once-dried conductive film, convection currents are generated in the droplets, which can effectively move the conductive material to the peripheral department. In this way, the semiconductor material does not remain in the central portion of the conductive film 520, and the semiconductor material can be deposited in a narrow ring shape. After the conductive material is deposited, heat treatment is performed on the obtained conductive film to aggregate metal fine particles, thereby improving the conductivity of the film.

(Source/drain region formation process)

Next, as shown in FIG. 22(A), so-called self-matching ion implantation is performed by using the regions 520a and 520b of the gate electrode 520 as masks to implant impurity elements serving as donors and acceptors.

For example, phosphorus (P) is implanted as an impurity element, and then the XeCl excimer laser is irradiated with an energy density of 400mJ/cm2 to activate the impurity element, thereby forming an N-type thin film transistor. In addition, instead of laser irradiation, impurity elements may be activated by heat treatment at about 250° C. to 400° C.

Regions 514a, 514b, and 514c are formed by implanting impurity elements using the regions 520a and 520b as masks. The region 514a serves as the drain region of the thin film transistor including the gate electrode 520a, and the region 514c serves as the drain region of the thin film transistor including the gate electrode 520a. The region 514b functions as a source region of the thin film transistor including the gate electrode 520a and the thin film transistor including the gate electrode 520b.

Next, as shown in FIG. 22(B), an insulating film 517 is formed over the gate insulating film 516 and the gate electrodes 520a and 520b. For example, a silicon oxide film of about 500 nm can be formed by PECVD. Next, contact holes reaching source region 514b and drain regions 514a and 514c are opened in insulating films 516 and 517 , and source/drain electrodes 528 are formed in the contact holes and around the contact holes of insulating film 517 . The source/drain electrodes 528 may be formed by depositing aluminum, for example, by sputtering. A contact hole across the gate electrode 528 is opened in the insulating film 517, and a terminal electrode (not shown) for the gate electrode is formed.

In the two thin film transistors formed as described above, the respective gate electrodes 520 a and 520 b form part of one ring-shaped conductive thin film 520 . Such transistors function as two transistors that share a source region and a gate electrode.

In the present embodiment, the above-mentioned two transistors can be manufactured by an easy and inexpensive process of arranging one droplet containing a conductive material and drying it. The width of the gate electrode 520 obtained by this method is less than 1 micron, so no patterning is required thereafter. By using the gate electrode as a mask to form source/drain regions, a semiconductor element with a gate length on the order of submicrons can be obtained, thereby becoming a high-performance thin film transistor with a small gate capacitance. According to the method of this embodiment, microfabrication and high density of semiconductor elements can be easily performed.

(droplet ejection device)

Each of the above-mentioned droplets is formed by being discharged from an inkjet type discharge device. The configurations of the inkjet discharge device and the inkjet head were described in the first embodiment with reference to FIGS. 3 and 4 , and descriptions thereof are omitted here.

<Tenth Embodiment>

A semiconductor device according to a tenth embodiment of the present invention is shown in FIGS. 23(A) and 23(B). In this embodiment mode, a double-connected thin film transistor is manufactured using the thin film transistor manufacturing method of the present invention. A double-connected thin film transistor means that two thin film transistors are connected in series. A cross-sectional view along line XXIIIB-XXIIIB of FIG. 23(A) is FIG. 23(B).

In the manufacturing method of this embodiment, the semiconductor film forming step, the insulating film forming step, the droplet arrangement step, and the conductive material deposition step are performed by the method described in the first embodiment above or a method based thereon, and description thereof will be omitted here. .

(Gate electrode separation process)

In the present embodiment, after a conductive thin film is deposited in a ring shape on an insulating film by a closed-loop phenomenon, a part thereof is removed to separate each gate electrode facing each channel region of a double-connected thin film transistor. The separated state plan view is Fig. 23(A). The gate electrodes 566a and 566b respectively opposing the channel regions 563a and 563b of the double-connected thin film transistors are in the shape of islands separated from each other as shown in FIG. 23(A) .

As the method of removing the thin film, a method of supplying an acidic solution such as hydrochloric acid or sulfuric acid and removing the acidic solution together with the unnecessary conductive thin film, a method of peeling off the silicon oxide film with hydrofluoric acid, or an etching method can be used. The area of the removed film is not on the order of submicron, so etching is a relatively inexpensive general method.

(Source/drain region formation process)

Next, as shown in FIG. 23(A), impurity elements serving as donors and acceptors are implanted using the gate electrodes 566a and 566b as masks to perform so-called self-matching ion implantation.

For example, phosphorus (P) is implanted as an impurity element, and then XeCl excimer laser is irradiated with an energy density of about 400mJ/cm ² to activate the impurity element, thereby forming an N-type thin film transistor. In addition, instead of laser irradiation, impurity elements may be activated by heat treatment at about 250° C. to 400° C.

Regions 564a, 564b, and 564c are formed by implanting an impurity element using the gate electrodes 566a and 566b as masks. The region 564a serves as the source region of the thin film transistor including the gate electrode 566a, and the region 564b serves as the drain region of the thin film transistor including the gate electrode 566a, and also serves as the source region of the thin film transistor including the gate electrode 566b. Furthermore, the region 564c functions as a drain region of the thin film transistor including the gate electrode 566b.

Next, as shown in FIG. 23(B), an insulating film 517 is formed over the gate insulating film 516 and the gate electrodes 566a and 566b. For example, a silicon oxide film of about 500 nm can be formed by PECVD. Next, contact holes reaching the regions 564a, 564b, and 564c are opened in the insulating films 516 and 517, and source/drain electrodes 568 are formed in the contact holes and around the contact holes of the insulating films 517. The source/drain electrodes 568 may be formed by depositing aluminum by, for example, sputtering. A contact hole across the gate electrodes 566a and 566b is opened in the insulating film 517 to form a gate electrode terminal electrode (not shown).

In the present embodiment, two separate island-shaped gate electrodes for a double-connected thin film transistor can be formed at desired positions by an easy and inexpensive process of disposing a droplet of a conductive material and drying it. The resulting gate electrode has a submicron-order width, so there is no need for subsequent patterning, and the gate capacitance of the semiconductor device can be reduced. Since it is easy to form a double-connected thin film transistor, microfabrication and high density of semiconductor elements can be easily performed.

<Eleventh Embodiment>

FIG. 24 shows a semiconductor device according to an eleventh embodiment of the present invention, and FIG. 25 shows a cross-sectional view taken along line XXV-XXV of the semiconductor device shown in FIG. 24 . In addition, FIG. 26 shows an equivalent circuit diagram of the semiconductor device of the present embodiment. The semiconductor device of this embodiment includes four thin film transistors T1 to T4, and the source electrodes 672a, 672c, 672e and drain electrodes 672b, 672d of the thin film transistors T1 to T4 are shared respectively (see FIGS. 24 and 26 ). On the other hand, the gate electrodes 674a to 674d of the respective thin film transistors T1 to T4 are formed, as shown in FIG. . Such a transistor is a multi-channel transistor whose channels are connected in parallel, and as a whole is used as a single transistor having a large channel width. A semiconductor device having this configuration is formed as follows.

As described above, first, the semiconductor film 675 to be a semiconductor layer is formed on the insulating film 67 formed on the substrate 670 by using CVD, PVD, or the like (see FIG. 25 ). A plurality of channel regions are subsequently formed on the semiconductor layer. A gate insulating film 673 having a flat surface is formed by covering the thus formed semiconductor film 675 and insulating film 671 with an SOG film. Then, droplets containing a conductive material are sequentially dropped on the gate insulating film 673 using an inkjet discharge device (see FIG. 4 ), to form a plurality of ring-shaped conductive thin films (conductive patterns) 674 . Specifically, first, a first droplet containing a conductive material is dropped so as to face each channel region (a region sandwiched between a source region and a drain region). The dropped droplet dries faster at the peripheral portion than at the central portion, so that the droplet flows from the central portion to the peripheral portion, and the conductive material reaches the peripheral portion. As a result, a ring-shaped conductive film 674 (for example, the ring-shaped conductive film on the left side shown in FIG. 24 ) is formed that follows the shape of the first droplet.

After the ring-shaped conductive film 674 corresponding to the first liquid droplet is formed, the second liquid is dropped so that it includes a part of the ring-shaped conductive film 674 (in other words, a part overlaps between each droplet) and a part of the peripheral portion. The respective channel regions are opposed to each other. As a result, a ring-shaped conductive film 674 (for example, the ring-shaped conductive film on the right side shown in FIG. 24 ) is formed that follows the shape of the second droplet. By forming these two ring-shaped conductive thin films 674, gate electrodes 674a to 674d which are a part of each conductive thin film 674 are formed. In this way, four droplets for 4-connected thin film transistors can be formed at desired positions with a width of submicron order by only dropping a plurality of droplets containing conductive material at positions shifted by a predetermined amount and drying them, which is easy and cheap. Gate electrodes 674a to 674d. Since the four gate electrodes are formed as part of two ring-shaped conductive thin films, they are electrically connected to each other.

Afterwards, self-matched ions that become donors or acceptors are properly implanted using the formed gate electrodes 674a-674d as a mask, thereby forming source regions 675a, 675c, 675e, drain regions 675b, 675d, and source regions and A plurality of channel regions sandwiched between the drain regions (see FIG. 25 ). Through the steps described above, a multi-channel semiconductor device including four thin film transistors having a gate length on the order of submicron as shown in FIG. 25 and continuous gate electrodes connected to each other can be obtained. In addition, four thin film transistors have been described in this embodiment, but three thin film transistors or five thin film transistors may be used. At this time, such a thin film transistor can be formed by increasing the number of droplets to be arranged or adjusting the arrangement of the source region and the drain region.

In addition, in the above description, the case where two ring-shaped conductive films 674 are formed to form four thin film transistors is exemplified, but the number of ring-shaped conductive films 674 may correspond to the number of n (n≥2) connections to be formed. The number of thin film transistors is appropriately changed (see FIG. 27). In addition, the arrangement interval and the diameter of each ring-shaped conductive thin film 674 can also be appropriately changed according to the design and the like of the thin film transistor to be formed.

<Twelfth Embodiment>

FIG. 28 shows a semiconductor device according to a twelfth embodiment of the present invention, and FIG. 29 shows an equivalent circuit diagram of the semiconductor device according to this embodiment. The semiconductor device according to this embodiment is a semiconductor device having a structure in which thin film transistors T1 to T4 having gate electrodes separated from each other in an island shape are connected in series (see FIG. 29 ). The gate electrodes 674a to 674d forming the respective thin film transistors T1 to T4 are formed by removing part of the two ring-shaped conductive thin films 674 shown in FIG. 24 above. The method of forming each of the gate electrodes 674a to 674d will be described. First, as described in the third embodiment, a plurality of droplets containing a conductive material are dropped to form two ring-shaped conductive thin films 674 .

Next, from these ring-shaped conductive thin films 674, unnecessary portions of the thin films (that is, thin films other than the portion facing the channel region) are removed to obtain gate electrodes 674a to 674d. As a thin film removal method, a method of supplying an acidic solution such as hydrochloric acid or sulfuric acid and removing the acidic solution together with an unnecessary conductive thin film, a method of peeling off a silicon oxide film with hydrofluoric acid, an etching method, and the like can be used. The area where the conductive thin film is removed is not on the order of submicrons, so etching is a relatively inexpensive general-purpose method. After removing unnecessary conductive thin films, gate electrode pads (pads) 676 (see FIG. 28 ) can be formed as necessary.

In addition, in this embodiment mode, a 4-connection thin film transistor is described, but a 3-connection thin film transistor or a 5-connection thin film transistor may be used. At this time, such a thin film transistor can be formed by increasing the number of droplets arranged, or adjusting the arrangement of the source region and the drain region.

<Thirteenth Embodiment>

FIG. 30 shows a semiconductor device according to a thirteenth embodiment of the present invention. The semiconductor device of this embodiment mode has the same circuit structure as that of the semiconductor device shown in FIG. 28 above, and the method of forming the gate electrode is different from this semiconductor device. Next, the gate electrode forming method of this embodiment will be described.

FIG. 31 is a diagram for explaining a method of forming a gate electrode according to the present embodiment.

First, as shown in FIG. 31(A), a first droplet containing a conductive material is dropped and dried to form a ring-shaped conductive thin film 674 that follows the shape of the first droplet. Next, the second liquid is dropped so as to include part of the ring-shaped conductive thin film 674 (see FIG. 31(B)). At this time, by controlling the dispersant of the second droplet, the drying speed, the particle size, contact angle, concentration, and time interval from the first droplet to the second droplet of the conductive material contained in the second droplet, and then A portion of the ring-shaped conductive film 674 contained in the second droplet (ie, the ring-shaped conductive film formed by the first droplet) is dispersed or redissolved. In this way, after redispersing or redissolving the ring-shaped conductive film 674 contained in the second droplet, the second droplet is dried, etc., to form a ring-shaped conductive film that follows the shape of the second droplet as shown in FIG. 31(C). 674.

After repeating the above-described series of steps in accordance with the number of gate electrodes, the unnecessary parts of the gate electrodes are removed from each calculated (measured) conductive film 674 (refer to the tenth embodiment), and the gate electrode 674a shown in FIG. 30 is obtained. ~674d. Gate electrodes of a plurality of thin film transistors having submicron order widths can be formed by an easy and inexpensive process of drying them. In this embodiment, as in the tenth embodiment, the conductive thin film is partially removed to make the respective gate electrodes 674a to 674d independent, but the conductive thin film may be connected to each other without removing the conductive thin film.

<Fourteenth embodiment>

FIG. 32 shows the configuration of a semiconductor device according to a fourteenth embodiment of the present invention. The semiconductor device of this embodiment has the same circuit configuration as the semiconductor device shown in FIG. 30 above, and only the shape of the gate electrode is different. Specifically, the gate electrodes 674a to 674d shown in FIG. 32 are substantially linear. A method for forming such a linear gate electrode will be described below.

FIG. 33 is a diagram for explaining a method of forming a gate electrode according to the present embodiment.

In this embodiment, in order to obtain a substantially linear gate electrode, the droplets containing the conductive material are continuously dropped at time intervals faster than the drying time of the droplets (see FIG. 33(A). Specifically, the droplets dropped first (For example, the uppermost droplet shown by the dotted line in FIG. The droplet in the center shown by the dotted line in A). Each dropped droplet fuses by wetting and spreading, and finally obtains a pair of two continuous pairs at the end of each droplet as shown in Figure 33(A). A substantially linear conductive film (hereinafter referred to as a linear conductive film).

In this way, when forming two pairs of linear conductive films 674 (corresponding to the gate electrodes 674a, 674b shown in FIG. Conductive film 674. However, in this embodiment, the arrangement interval w1 (see FIG. 33(C)) of each gate electrode is set narrower than the interval w2 (see FIG. 33(C)) between two pairs of linear conductive thin films 674, Therefore, droplets can be dropped continuously so as to include a part of the already formed linear conductive thin film 674 .

As a result, as shown in FIG. 33(C), gate electrodes 647a to 674d composed of two pairs of linear conductive thin films 674 formed in two layers are obtained. According to the method described above, a plurality of gate electrodes of thin film transistors having widths on the order of submicron can be formed by dropping a plurality of liquid droplets containing a conductive material and drying them, which is easy and inexpensive. In this embodiment, the arrangement interval w1 of each gate electrode is set to be narrower than the interval w2 between two pairs of linear conductive thin films 674, but it is of course possible to set the arrangement interval w1 of each gate electrode to be smaller than The interval w2 between two pairs of linear conductive thin films 674 is wide.

In addition, in the above-mentioned embodiments, the semiconductor region represents one continuous region, but island regions may be formed for each of the plurality of transistors. In this case, the source and drain regions of each transistor are independent, and there are more patterns than the case of forming a circuit. The configuration of the source and drain regions in various embodiments may be opposite to each other sandwiching the channel regions.

<Fifteenth embodiment>

A fifteenth embodiment of the present invention relates to an electro-optical device including a semiconductor device or the like manufactured by the thin film transistor manufacturing method of the present invention. An example of an electro-optical device is an organic EL (electroluminescence) display device.

FIG. 34 is a diagram illustrating the configuration of an electro-optical device 100 according to a fourth embodiment. The electro-optical device (display device) 100 of this embodiment includes: a circuit substrate (active matrix substrate) configured by arranging pixel driving circuits including thin film transistors T1 to T4 in a matrix on the substrate; A light-emitting layer that emits light; drivers 101 and 102 that supply driving signals to a pixel driving circuit including thin film transistors T1 to T4 are configured. The driver 101 supplies a driving signal to each pixel region through the scanning line Vsel and the light emission control line Vgp. The driver 102 provides driving signals to each pixel area through the data line Idata and the power line Vdd. By controlling the scan line Vsel and the data line Idata to perform a current program for each pixel area, the light emission of the light emitting part OELD can be controlled. The thin film transistors T1 - T4 and the drivers 101 , 102 constituting the pixel driving circuit are formed by applying the above-mentioned manufacturing method of the first or second embodiment.

In addition, an organic EL display device was described as an example of an electro-optical device, but various electro-optical devices such as liquid crystal display devices can be similarly manufactured.

Next, various electronic devices configured by applying the electro-optical device 100 of the present invention will be described. FIG. 35 is a diagram showing an example of an electronic device using the electro-optical device 100 . Fig. 35 (A) is the application example to mobile phone, and this mobile phone 230 is provided with antenna part 231, sound output part 232, sound input part 233, operation part 234, and electro-optical device 100 of the present invention. Thus, the electro-optical device of the present invention can be used as a display unit. FIG. 35(B) is an example of application to a video camera. The video camera 240 includes an image receiving unit 241, an operating unit 242, a voice input unit 243, and the electro-optical device 100 of the present invention. In this way, the electro-optical device of the present invention can be used as a viewfinder or a display unit. FIG. 35(C) is an application example to a portable personal computer (so-called PDA), and this computer 250 is equipped with a camera unit 251, an operation unit 252, and the electro-optical device 100 of the present invention. Thus, the electro-optical device of the present invention can be used as a display unit.

FIG. 35(D) is an example of application to a head-mounted display. This head-mounted display 260 is equipped with a strap 261, an optical system housing portion 262, and the electro-optical device 100 of the present invention. Thus the electro-optical device of the present invention can be used as an image display source. In addition, the electro-optical device 100 of the present invention is not limited to the above-mentioned examples, and can be applied to all electronic devices that can use display devices such as organic EL display devices and liquid crystal display devices. For example, it can also be used flexibly in facsimile equipment with a display function, a viewfinder of a digital camera, a portable TV, an electronic notebook, an electro-optical bulletin board, and a display for advertisements.

FIG. 36(A) is an example of application to a television set 300 equipped with the electro-optical device 100 of the present invention. The electro-optical device of the present invention is also applicable to a monitor device used for a personal computer or the like. FIG. 36(B) is an example of application to a roll-up TV set equipped with the electro-optical device 100 of the present invention.

The manufacturing methods of the above-described embodiments can be used in the manufacture of various devices other than the manufacture of electro-optical devices. For example, various memories such as FeRAM (ferroelectric RAM), SRAM, DRAM, NOR RAM, NAND RAM, floating gate nonvolatile memory, and magnetic RAM (MRAM) can be manufactured. In a non-contact communication system to which microwaves are applied, it is also applicable to manufacture of inexpensive tags on which tiny circuit chips (IC chips) are mounted.

The present invention is not limited to the contents of the above-described embodiments, and various modifications can be made within the scope of the present invention. For example, in the above-described embodiments, a silicon film has been used as an example of a semiconductor film for description, but the semiconductor film is not limited thereto. In the above embodiments, a thin film transistor was used as an example of a semiconductor element formed using the semiconductor film of the present invention. However, the semiconductor element is not limited thereto, and other elements (for example, thin film diodes, etc.) may be formed. In addition, the thin film transistor of the present invention can be used as a transistor of an integrated circuit in addition to being used as a pixel transistor.

Claims (21)

1. A method of manufacturing a thin film transistor, comprising a semiconductor film, a channel region provided on the semiconductor film, a source region and a drain region arranged to sandwich the channel region, and a gate insulating film opposite to the channel region A method for manufacturing a thin film transistor with a gate electrode, characterized in that it includes: the process of disposing droplets comprising a semiconductor material on a substrate; A step of drying the droplet to cause a closed-loop phenomenon, and depositing the semiconductor material at least around the droplet; When the semiconductor material is deposited in the center of the droplet, the semiconductor film is formed by removing the semiconductor material in the center. 2. The manufacturing method of the thin film transistor according to claim 1, wherein In the step of disposing the above-mentioned liquid droplets, disposing two or more of the above-mentioned liquid droplets, In the step of forming the above-mentioned semiconductor film, the above-mentioned semiconductor film material is deposited on the periphery of the droplet shape obtained when the above-mentioned two or more droplets are fused. 3. The manufacturing method of the thin film transistor according to claim 1 or 2, further comprising: After the process of arranging the above-mentioned droplets, convection is generated in the droplets by adjusting the temperature of the substrate, or by spraying the droplets again on the temporarily dried semiconductor film to control the gasification state or viscosity of the droplets, and effectively A step of increasing the concentration of the semiconductor film material in the peripheral portion of the droplet by moving the semiconductor material to the peripheral portion of the droplet. 4. The method for manufacturing a thin film transistor according to claim 1, further comprising: A step of removing a part of the above-mentioned semiconductor film to divide the above-mentioned semiconductor film after the step of forming the above-mentioned semiconductor film; and The above-mentioned gate electrodes are formed to correspond to the steps of the above-mentioned divided semiconductor films, respectively. 5. The method of manufacturing a thin film transistor according to claim 1, wherein heat or light energy is supplied to the liquid droplets in the step of forming the semiconductor film. 6. The method of manufacturing a thin film transistor according to claim 1, further comprising a step of forming the source region and the drain region by implanting impurities into the semiconductor film after the step of forming the semiconductor film. 7. A method of manufacturing a thin film transistor comprising a channel region provided on a semiconductor film, a source region and a drain region corresponding to the channel region, and a gate electrode opposite to the channel region via a gate insulating film A method for manufacturing a transistor, characterized by comprising: a droplet arranging step of arranging the droplet so that the peripheral portion of the droplet containing the conductive material faces the channel region by controlling the wettability of the surface of the gate insulating film; and In the precipitation step, the above-mentioned droplet is dried to generate a closed-loop phenomenon, the above-mentioned conductive material is precipitated at least in the peripheral part of the droplet, and in the case of depositing the above-mentioned conductive material in the central part of the droplet, by removing the conductive material in the central part The above-mentioned conductive material is used to form a conductive film used as the above-mentioned gate electrode. 8. The method for manufacturing a thin film transistor according to claim 7, wherein A plurality of the channel regions are provided on the semiconductor film of one of the thin film transistors, and one or more droplets are arranged in the droplet arrangement step so that the peripheral portions of the droplets face the plurality of channel regions. In the deposition step, a plurality of gate electrodes respectively facing the plurality of channel regions are formed. 9. The method for manufacturing a thin film transistor according to claim 8, wherein In the above-mentioned deposition step, a removal step is provided for removing a part of the ring-shaped conductive material deposited on the periphery of the droplet, In the removing step, the ring-shaped conductive material is broken to form a plurality of gate electrodes respectively facing the plurality of channel regions. 10. The method for manufacturing a thin film transistor according to claim 7, wherein In the above-mentioned droplet arrangement step, arrange two or more droplets, In the deposition step, the conductive material is deposited on at least a peripheral portion of a droplet shape obtained when the two or more droplets are fused. 11. The method for manufacturing a thin film transistor according to claim 7, comprising: After the droplet disposition process described above, convection is generated in the droplet by adjusting the temperature of the substrate, or controlling the gasification state or viscosity of the droplet by spraying the droplet again on the temporarily dried conductive film, and effectively A step of increasing the concentration of the conductive material in the peripheral portion of the droplet by moving the conductive material to the peripheral portion. 12. A method of manufacturing two or more thin film transistors, comprising a semiconductor film with a channel region, a source region and a drain region facing each other across the channel region, and a gate insulating film facing the channel region A method for manufacturing a gate electrode of a thin film transistor, characterized in that it comprises: a droplet arrangement step, by controlling the wettability of the surface of the gate insulating film, a droplet containing a conductive material is arranged so that at least a part of the periphery of the droplet faces one or more of the above-mentioned channel regions; In the deposition step, the gate electrode is formed by depositing the conductive material only on the periphery of the droplet, wherein The formed gate electrodes are each connected to at least one other gate electrode. 13. The method for manufacturing a thin film transistor according to claim 12, wherein in the droplet arrangement step, two or more of the droplets are arranged such that at least a part of the periphery of each droplet is opposed to one or more of the droplets. In the channel region, at least a part of the peripheral portion of each droplet overlaps with the peripheral portion of at least one other droplet. 14. A method of manufacturing two or more thin film transistors, comprising a semiconductor film including a channel region, a source region and a drain region facing each other across the channel region, and a gate insulating film facing the channel region A method for manufacturing a gate electrode of a thin film transistor, characterized in that it comprises: a droplet arrangement step, by controlling the wettability of the surface of the gate insulating film, and arrange the droplets containing the conductive material so that at least a part of the periphery of each droplet faces one or more of the above-mentioned channel regions; a deposition step of forming the gate electrode by depositing the conductive material only on the periphery of the droplet; In the separation step, each gate electrode facing the channel region is formed in an island shape separated from a gate electrode facing the other channel region. 15. The method of manufacturing a thin film transistor according to claim 14, wherein in the separating step, the gate electrode is formed into a separate island shape by removing a part of the gate electrode. 16. The manufacturing method of a thin film transistor according to claim 14, wherein each of said thin film transistors has a set of a source region and a drain region for each of said separated gate electrodes. 17. The manufacturing method of a thin film transistor according to claim 13 or 14, wherein in the above-mentioned droplet arrangement step, the next droplet is arranged so as to overlap a part of the conductive material deposited in the periphery of the previously arranged droplet, The portion of the conductive material is redispersed. 18. The manufacturing method of the thin film transistor according to claim 12 or 14, wherein Each droplet configured in the above-mentioned droplet configuration step is further composed of two or more sub-droplets, In the deposition step, the conductive material is deposited on at least a peripheral portion of a droplet shape obtained when the two or more sub-droplets are fused. 19. The method of manufacturing a thin film transistor according to claim 12 or 14, wherein the semiconductor film of one of the thin film transistors is formed in an island shape separated from the semiconductor films of the other thin film transistors. 20. The method for manufacturing a thin film transistor according to claim 7 or 12, further comprising the step of forming the above-mentioned gate insulating film with a flat surface on each of the above-mentioned channel regions before the above-mentioned droplet arrangement step, In the step, liquid droplets are placed on the gate insulating film. 21. A method of manufacturing a semiconductor device in which a semiconductor element is formed using a semiconductor film formed on a substrate, comprising: the step of disposing droplets of a semiconductor material on the above-mentioned substrate; and A step of drying the droplet to cause a closed-loop phenomenon, and depositing the semiconductor material at least around the droplet; When the semiconductor material is deposited in the center of the droplet, the semiconductor film is formed by removing the semiconductor material in the center.

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