JP2005347764A - Method of manufacturing image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an image display device provided with an active matrix substrate having a high performance thin film transistor circuit operating at a high speed mobility in a driving circuit for driving pixel portions arranged in a matrix.
Irradiation while scanning a pulse modulated laser beam or pseudo CW laser beam on a polysilicon film formed in a drive circuit region DAR1 around a pixel region PAR of an active matrix substrate SUB1 constituting an image display device Then, a discontinuous modified region of the substantially band-like crystalline silicon film modified so as to have a continuous grain boundary in the scanning direction is formed. A drive circuit having an active element such as a thin film transistor is formed in the virtual tile TL formed in the discontinuous modified region so that the channel direction is substantially the crystal growth direction of the band-like crystalline silicon film.
[Selection] FIG.

Description

  The present invention relates to an image display device, and more particularly to an image display device in which a crystal structure of a semiconductor film formed on an insulating substrate is modified with laser light, and an active element of a drive circuit is formed on the modified semiconductor film. It relates to a manufacturing method.

  2. Description of the Related Art An active matrix display device (or an active matrix drive image display device, or simply a display device) using active elements such as thin film transistors as a driving element for pixels arranged in a matrix is widely used. Many image display devices of this type are arranged by arranging a large number of pixel circuits and drive circuits formed of active elements such as thin film transistors (TFTs) formed using a silicon film as a semiconductor film on an insulating substrate. A high-quality image can be displayed. Here, a thin film transistor which is a typical example of the active element will be described as an example.

  In a thin film transistor using an amorphous silicon semiconductor film (amorphous silicon semiconductor film) that has been generally used as a semiconductor film, there is a limit to the performance of the thin film transistor represented by its carrier (electron or hole) mobility. Therefore, it has been difficult to construct a circuit that requires high speed and high functionality. In order to realize a high mobility thin film transistor necessary to provide better image quality, an amorphous silicon film (hereinafter also referred to as an amorphous silicon film) is preliminarily formed into a polysilicon film (hereinafter also referred to as a polycrystalline silicon film). It is effective to form (thinner) the thin film transistor using a polysilicon film. For this modification, a technique of annealing the amorphous silicon film by irradiating laser light such as excimer laser light is used.

  For example, TC Angelis et al; Effect of Excimer Laser Annealing on the Structural and Electrical Properties of Polycrystalline Silicon Thin-Film Transistor, J. Appl. Phy., Vol. 86, pp4600-4606, 1999 or H. Kuriyama et al; Lateral Grain Growth of Poly-Si Films with a Specific Orientation by an Eximer Laser Annealing Method, Jpn.J.Appl.Phy., Vol.32, pp6190-6195,1993 or K.Suzuki et al; Correlation between Power Density Fluctuation and Grain Size Distribution of Laser annealed Poly-Crystalline Silicon, SPIE Conference, Vol.3618, pp310-319, 1999.

  A modification method by crystallization of an amorphous silicon film using excimer laser light irradiation will be described with reference to FIG. FIG. 34 is an explanatory view of a method for crystallizing an amorphous silicon film by scanning the most general excimer pulse laser beam irradiation. FIG. 34 (a) shows the configuration of an insulating substrate on which an irradiated semiconductor layer is formed. (B) shows a state modified by laser light irradiation. Glass or ceramics is used for this insulating substrate.

  In FIG. 34, an amorphous silicon film ASI deposited on an insulating substrate SUB via a base film (SiN or the like, not shown) is irradiated with a linear excimer laser beam ELA having a width of several nanometers to several hundred nanometers. As shown in FIG. 4, the amorphous silicon film ASI is annealed by performing scanning that moves the irradiation position every one to several pulses along one direction (x direction), and the amorphous silicon film ASI of the entire insulating substrate SUB is changed to polysilicon. Modification to film PSI. The polysilicon film PSI modified by this method is subjected to various processes such as etching, wiring formation, and ion implantation to form a circuit having an active element such as a thin film transistor in each pixel portion or driving portion. An active matrix type image display device such as a liquid crystal display device or an organic EL display device is manufactured using this insulating substrate.

  FIG. 35 is a partial plan view of the laser beam irradiation part in FIG. As shown in FIG. 35A, a large number of crystallized silicon particles (polycrystalline silicon) PSI of about 0.05 to 0.5 μm grow uniformly in the plane in the laser beam irradiation part. Most of the grain boundaries of each silicon particle (that is, silicon crystal) are closed by themselves (there is a grain boundary between adjacent silicon particles in all directions). In FIG. 35A, a portion surrounded by a square is a transistor portion TRA that becomes a semiconductor film for an active element such as an individual thin film transistor. The conventional modification of the silicon film means such crystallization.

  In order to use the modified silicon film (polysilicon film PSI) to form a pixel circuit, as shown in FIG. 35B, a portion of the crystallized silicon is used as a transistor portion. Unnecessary portions other than the portion to be the transistor portion TRA in FIG. 35A are removed by etching to form an island (island) of a silicon film, and a gate insulating film (not shown) and gate are formed on the island PSI-L. A thin film transistor is manufactured by arranging the electrode GT, the source electrode SD1, and the drain electrode SD2.

  In the above prior art, a thin film transistor is formed on a modified polysilicon film on an insulating substrate and an active element such as a thin film transistor having good operation performance is disposed. For example, there is a limit to the carrier mobility (electron mobility or hole mobility, hereinafter also simply referred to as electron mobility) in the channel of a thin film transistor using the above. That is, the grain boundaries of the polysilicon film crystallized by the excimer laser light irradiation are closed for each individual crystal as shown in FIG. 34, and in the channel between the source electrode and the drain electrode. There is a limit to achieving greater carrier mobility. With the recent high definition, the circuit density of the drive circuit has become dense. An active element such as a thin film transistor having a very high circuit density in such a drive circuit is required to have a higher carrier mobility.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing an image display device including an active matrix substrate having a high-performance thin film transistor circuit or the like that operates with high-speed mobility in a driving element for driving pixel portions arranged in a matrix. Is to provide. The present invention is not limited to the modification of a polysilicon semiconductor film formed on an insulating substrate for an image display device, but to the modification of a similar semiconductor film formed on another substrate such as a silicon wafer. Can be applied similarly.

  As means for solving the above-mentioned problems, the present invention has modified the polysilicon film by irradiating the entire surface of the amorphous silicon film formed on the entire area of the insulating substrate with the excimer laser beam, or formed the polysilicon film. An insulating substrate is prepared, and a predetermined direction is applied while selectively irradiating a polysilicon film in a drive circuit region disposed around the pixel region of the insulating substrate with a pulse modulated laser beam or a pseudo CW laser beam using a solid laser. In this way, a discontinuous modified region of a substantially band-shaped crystalline silicon film having a large crystal size modified so that crystals grown in the scanning direction have continuous grain boundaries is formed.

  The discontinuous reforming region is generally rectangular, and when a required circuit such as a drive circuit is formed in the rectangular discontinuous reforming region, the channel direction of the active elements such as thin film transistors constituting the circuit is It is made to be substantially parallel to the grain boundary direction of the substantially band-like crystalline silicon film. In the present invention, a method for creating a discontinuous modified region of a substantially band-shaped crystalline silicon film by irradiation with the above-described pulse-modulated laser light is referred to as SELAX (Selective Enhancing Laser Crystallization).

  In the manufacture of the image display device according to the present invention, preferably, the SELAX for selectively irradiating the polysilicon film of the drive circuit portion with a laser beam (hereinafter also referred to as laser light or simply laser) using a reciprocating operation. A discontinuous modified region of the substantially band-shaped crystalline silicon film is formed by the treatment. Although the discontinuous reforming region can be formed in the entire region of the drive circuit region, it is recommended that the discontinuous reforming region be formed in a substantially rectangular shape in a necessary region in consideration of the circuit density of the drive circuit. In particular, by forming the substantially rectangular discontinuous modified region mainly in the necessary region of the drive circuit region, the efficiency of the laser light irradiation treatment and the film quality of each substantially band-like crystalline silicon film are all improved. Uniformity can be achieved in the discontinuous reforming region.

The substantially band-like crystalline silicon film according to the present invention has a width in the direction perpendicular to the scanning direction of the laser beam and the length in the scanning direction, for example, a width of about 0.1 μm to 10 μm and a length of about 1 μm to 100 μm. It is an aggregate of crystals. Good carrier mobility can be secured by using such a substantially band-like crystalline silicon film. The value is about 300 cm ² / V · s or more, preferably 500 cm ² / V · s or more as the electron mobility.

On the other hand, in the modification of a silicon film using a conventional excimer laser, a large number of crystallized silicon particles (polysilicon) of about 0.05 μm to 0.5 μm grow randomly in the laser light irradiation portion. The electron mobility of such a polysilicon film is about 200 cm ² / V · s or less, and on average about 120 cm ² / V · s. Although the performance is improved as compared with the electron mobility of the amorphous silicon film of 1 cm ² / V · s or less, the discontinuous modified region formed of the substantially band-like crystalline silicon film of the present invention has the above-described electron mobility. The electron mobility is even faster than the degree.

  The silicon film in the pixel region of the insulating substrate constituting the image display device according to the present invention is a polysilicon film obtained by modifying an amorphous silicon film formed by a CVD method or a sputtering method by irradiation with an excimer laser beam, and a drive circuit region. The silicon film is a substantially band-like crystalline silicon film whose crystal structure is further modified by irradiation of a pulse modulated laser beam using a solid laser or a pseudo CW laser beam on a polysilicon film. The pulse modulation referred to here means a modulation method for changing a pulse width or a pulse-to-pulse interval, or both. Specifically, such a modulated pulse can be obtained by electro-optic modulation (Electro-Optic modulation: EO modulation) of a CW (continuous oscillation) laser.

  In the present invention, by selectively irradiating the polysilicon film in the drive circuit area on the insulating substrate while scanning with the pulse modulated laser beam, the area is selectively irradiated, that is, the band-shaped crystalline silicon film is modified. The regions are formed in a substantially rectangular array along the insulating substrate surface. Hereinafter, the substantially rectangular area is also referred to as a virtual tile. The virtual tiles and the individual modified regions constituting the virtual tiles are arranged in blocks for each of the plurality of circuit areas formed thereafter. By adopting such virtual tiles, in addition to the effects described above, it is not necessary to irradiate laser light to the region of the semiconductor film that is removed by etching in the process of forming a thin film transistor or the like, greatly reducing unnecessary work. Can be reduced.

  An excimer laser used when the amorphous silicon film is modified into a polysilicon film in the present invention, a continuous wave solid laser having an oscillation wavelength of 200 nm to 1200 nm, or a solid pulse laser in the same frequency range is preferable. The continuous wave laser beam preferably has a wavelength that is absorbed by the amorphous silicon to be annealed, that is, an ultraviolet wavelength to a visible wavelength. More specifically, an Ar laser, an Nd: YAG laser, an Nd: YVO4 laser, and an Nd: YLF laser. The second harmonic, the third harmonic, the fourth harmonic, and the like are applicable. However, in consideration of the output size and stability, the second harmonic (wavelength 532 nm) of an LD (laser diode) pumped Nd: YAG laser or the second harmonic (wavelength 532 nm) of an Nd: YVO4 laser is most desirable. The upper and lower limits of the wavelength are determined by the balance between the range in which the light absorption of the silicon film is efficiently generated and a stable laser light source that is economically available. This polysilicon film can also be formed at the stage of film formation. For example, it can be directly formed on a substrate or a substrate by a cat-CVD (catalytic vapor deposition) method.

  The solid-state laser of the present invention is characterized in that it can stably supply the laser light absorbed by the silicon film, and has less economic burden such as gas exchange work and deterioration of the transmitter characteristic of the gas laser. It is preferable as a means for modifying. However, the present invention does not actively exclude that the laser is an excimer laser having a wavelength of 150 nm to 400 nm.

  In the present invention, the laser used to modify the polysilicon film into a substantially band-like crystalline silicon film is a continuous wave solid state laser or pulse modulated solid state laser having an oscillation wavelength of 200 nm to 1200 nm, or a pseudo CW solid state laser (pseudo continuous wave solid state laser). It is preferable that The pseudo-CW solid-state laser can consider a high-frequency pulsed laser as a pseudo-continuous laser and use a so-called mode-lock technique to obtain a pulsed laser with a frequency of 100 MHz or higher even in the UV region. . Even if the irradiation laser is a short pulse, if the next pulse is irradiated within the solidification time (<100 ns) of silicon, the melting time can be extended without solidifying the silicon film. Can be considered. In addition, by combining with electro-optic modulation (Electro-Optic modulation: EO modulation), a polycrystalline silicon film (substantially band-shaped crystalline silicon film) that absorbs laser energy with high efficiency and controls the length in the scanning direction of the laser beam. Can be obtained.

  In the present invention, it is desirable that the laser light is optically adjusted to make the spatial distribution of the intensity uniform and then condensed and irradiated using a lens system. In the present invention, the irradiation width when the laser beam is irradiated by intermittent scanning is determined in consideration of economic efficiency from both the width of the area necessary for the drive circuit area and the ratio to the pitch. The width and length of the irradiation part forming the virtual tile shape are determined in consideration of the size of the application circuit, the degree of integration, and the like. The present invention is not limited to scanning the insulating substrate by moving the laser beam, but placing the insulating substrate on the XY stage and intermittently irradiating the laser beam in synchronization with the movement of the XY stage. You may make it carry out.

  In the present invention, it is desirable to scan with continuous pulse laser beam irradiation at a speed of 50 mm / s to 3000 mm / s. The lower limit of the scanning speed is determined from the balance between the time required to scan the drive circuit area in the insulating substrate and the economic burden. The upper limit of the irradiation speed is limited by the capacity of the mechanical equipment used for scanning.

  In the present invention, the laser irradiation scans the laser beam using a beam converged by an optical system. At this time, an optical system that converges a single laser beam into a single beam may be used. However, it is suitable for a case where a large-sized substrate is processed in a short time by irradiating a single laser beam divided into a plurality of parts and simultaneously irradiating a plurality of columns of pixel portions with simultaneous scanning. It is possible to significantly improve the efficiency of laser light irradiation. In the present invention, the laser beam irradiation may operate a plurality of laser oscillators in parallel, and this method is particularly preferable when a large-sized substrate is processed in a short time.

  Furthermore, in the present invention, the active element circuit formed of the silicon film modified into a substantially band-like crystal is not limited to a general top gate type thin film transistor circuit, and may be a bottom gate type thin film transistor circuit. . When a single channel circuit having only an N channel MIS or a P channel MIS is required, a bottom gate type may be preferable in some cases because of simplification of the manufacturing process. In such a case, since a silicon film with an insulating film on the gate wiring is modified to a substantially band-like crystalline silicon film by laser irradiation, a refractory metal is preferably used as the gate wiring material, and tungsten (W) Alternatively, it is preferable to use a gate wiring material mainly composed of molybdenum (Mo).

  By using an insulating substrate having a semiconductor structure such as a thin film transistor of the driving circuit of the present invention as an active matrix substrate, a liquid crystal display device with excellent image quality can be provided at low cost. Further, by using the active matrix substrate of the present invention, an organic EL display device having excellent image quality can be provided at low cost. Further, the present invention is not limited to a liquid crystal display device and an organic EL display device, but other types of active matrix type image display devices having a similar semiconductor structure in a drive circuit, and various semiconductors fabricated on a semiconductor wafer. It is also applicable to the device.

  The present invention relates to a substantially band-like crystal selectively modified by irradiating a pulse modulation laser beam or a pseudo CW laser beam onto a silicon film constituting a circuit of a drive circuit region disposed around a pixel region of an active matrix substrate. High performance that operates with high mobility by adopting a new method of forming a discontinuous modification region of silicon film and forming a drive circuit consisting of active elements such as thin film transistors in this discontinuous modification region Image display device can be obtained.

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

  FIG. 1 is a plan view for schematically explaining a liquid crystal display device as an example of an image display device manufactured by applying the manufacturing method according to the present invention. In FIG. 1, reference numeral SUB1 is an active matrix substrate, SUB2 is a color filter substrate bonded to the active matrix substrate SUB1, and an end portion bonded via a liquid crystal layer is indicated by a virtual line. Although a color filter or a common electrode is formed on the inner surface of the color filter substrate SUB2, the illustration is omitted in FIG. In the following, a liquid crystal display device using a color filter substrate as described above will be described as an example. However, the present invention can be similarly applied to a liquid crystal display device in which a color filter is formed on the active matrix substrate side.

  The active matrix substrate SUB1 has a pixel region PAR at the center of the active matrix substrate SUB1, and a drive circuit region DAR1 in which a circuit for supplying drive signals to a large number of pixels formed in the pixel region PAR outside the pixel region PAR is formed. , DAR2, and DAR3. In this embodiment, data drive circuits DDR1, DDR2,... DDRn-1, DDRn for supplying display data to the pixels are formed on one long side (the upper side in FIG. 1) of the active matrix substrate SUB1. The drive circuit area DAR1 thus arranged is arranged. In addition, on both sides (left and right sides in FIG. 1) adjacent to the drive circuit area DAR1, the drive circuit area DAR2 having the scanning circuits GDR1 and GDR2 is arranged. A drive circuit region DAR3 having a so-called precharge circuit is disposed on the other long side (lower side in FIG. 1) of the active matrix substrate SUB1.

  The four corners where the active matrix substrate SUB1 and the color filter substrate SUB2 overlap each other have pads CPAD for supplying a common electrode potential from the active matrix substrate SUB1 side to the common electrode of the color filter substrate SUB2. The pads CPAD are not necessarily provided at the four corners, and may be provided at any one corner, or any two or three corners.

  An input terminal DTM (DTM1) of the data drive circuit DDR (DDR1, DDR2,... DDRn-1, DDRn) is provided at an edge of the active matrix substrate SUB1 that does not overlap with the one long side color filter substrate SUB2. , DTM2,... DTMn-1, DTMn) and input terminals GTM (GTM1, GTM2) of the scanning circuit GDR (GDR1, GDR2) are formed. Pixels arranged in a matrix in the pixel region PAR are provided at an intersection of a data line DL extending from the data driving circuit DDR and a gate line GL extending from the scanning circuit GDR. This pixel includes a thin film transistor TFT and a pixel electrode PX.

  In such a configuration, the thin film transistor TFT connected to the gate line GL selected by the scanning circuit GDR (GDR1, GDR2) is turned on, and the data driving circuit DDR (DDR1, DDR2,... DDRn-1, DDRn). The display data voltage supplied via the data line DL extending from the pixel electrode PX is applied to the pixel electrode PX, and an electric field is generated between the pixel electrode PX and the common electrode on the color filter substrate SUB2 side. By this electric field, the liquid crystal alignment direction of the liquid crystal layer in the pixel portion is modulated to display the pixel.

  In the liquid crystal display device shown in FIG. 1, the scanning circuit GDR is divided into two systems GDR1 and GDR2, which are arranged on the left and right sides of the active matrix substrate SUB1, and each gate line extending from each scanning circuit GDR1 and GDR2 GLs are alternately arranged in a comb shape. However, the present invention is not limited to this, and one scanning circuit GDR may be provided and arranged on one of the left and right sides of the active matrix substrate SUB1. In the following description, an example in which one scanning circuit GDR is used as described above will be described. The present invention can be applied to all of the drive circuit areas DAR1, DAR2, and DAR3 described above, but is mainly applied to the drive circuit area DAR1 having the finest circuit configuration.

  FIG. 2 is a block diagram illustrating an example of the circuit configuration of the data drive circuit portion in FIG. In FIG. 2, reference symbol PAR indicates a pixel region. In the pixel region, the pixels PX are arranged in a matrix in the horizontal (x) direction and the vertical (y) direction (the pixel is indicated by a pixel electrode PX). Reference numeral DDR denotes a data driving circuit. The data driving circuit DDR includes a horizontal shift register HSR, a first latch circuit LT1 composed of a latch circuit LTF, a second latch circuit LT2 composed of a latch circuit LTS, a digital-analog converter DAC composed of a digital-analog converter circuit D / A, and a buffer It comprises a circuit BA, a sampling circuit SAMP comprising a sampling switch SSW, and a vertical shift register VSR.

  Various clock signals CL input from a signal source (not shown) through the input terminal DTM enter the horizontal shift register HSR and cross the data driving circuits DDR (DDR1, DDR2,... DDRn-1, DDRn). Sequentially transferred. Further, the display data DATA is latched by the first latch circuit LT1 from the data line DATA-L. The display data latched by the first latch circuit LT1 is latched by the second latch circuit LT2 by a latch control signal applied to the latch control line. The display data latched by the second latch circuit LT2 is supplied to the pixel PX connected to the gate line selected by the vertical shift register VSR in the pixel area PAR through the digital-analog converter DAC, the buffer circuit BA, and the sampling circuit SAMP. Is done.

  In this embodiment, a discontinuous reforming region of a substantially band-like crystalline silicon film modified so as to have a continuous grain boundary in the scanning direction by selective irradiation by scanning with a pulse-modulated laser beam in the data driving circuit DDR. Is applied. A range to which this discontinuous reforming region is applied is indicated by reference numeral SX. Ideally, the discontinuous reforming region should be provided in the entire range SX. However, discontinuous reforming may be applied to some of the circuits in consideration of production efficiency such as throughput. This discontinuous reforming region is indicated by reference numeral TL. Here, a case where the silicon film of the circuit portion constituting the sampling switch SSW in the discontinuous reforming region SX is reformed into a rectangular shape will be described as an example. Hereinafter, the rectangular region subjected to such discontinuous modification is also referred to as a virtual tile for convenience. The size of the virtual tile is set to a size corresponding to the circuit scale to be created or a size to create a plurality of circuits.

  FIG. 3 is a block diagram of a sampling switch portion constituting the sampling circuit in FIG. Each sampling switch SSW is formed in each of the virtual tiles TL arranged in a line in the x direction of FIG. The sampling switch SSW is composed of an analog switch, and its circuit configuration is finer than other components of the data driving circuit DDR and is closely arranged. Since the thin film transistor constituting the sampling switch SSW is formed in the discontinuous reforming region where the electron mobility is high, it can be formed with higher definition than other circuits. Since the signal lines R1, G1, B1, R2, G2, and B2 are arranged at a pixel pitch in the pixel region, the interval between the output lines (signal lines) is narrow at the output end of the sampling switch SSW. The wiring pattern has a wide interval.

  Note that the buffer circuit BF outputs display data input from the horizontal shift register HSR, three inverted signals, and a total of 12 pixels for two pixels. Here, a case where two pixels are processed by one horizontal shift register HSR is shown. Each color data (video signal) of each pixel has a reversed polarity. The sampling switch SSW determines which polarity signal of each pixel is sent. As shown in FIG. 2, due to the structure of the sampling switch SSW, the polarities of adjacent pixels are always inverted. In FIG. 3, R1 is a signal line for pixel 1 (red), G1 is a signal line for pixel 1 (green), B1 is a signal line for pixel 1 (blue), R2 is a signal line for pixel 2 (red), and G2 is a pixel line 2 (green) signal line and B2 are pixel 2 (blue) signal lines.

  FIG. 4 is an enlarged plan view for explaining one configuration of the sampling switch circuit formed in the virtual tile portion shown in FIG. 3, and FIG. 5 is a further enlarged view of the main part of FIG. It is a schematic diagram of the channel part of the thin-film transistor (TFT) which shows. The virtual tile TL is modified by scanning in the scanning direction x (or -x) direction of the pulse-modulated laser light. In the virtual tile TL, a portion indicated by reference sign LD-P is a silicon island where a P-type TFT is formed, and a portion indicated by LD-N is a silicon island where an N-type TFT is formed.

  As shown in FIG. 5, the grain boundary CB existing between the single crystals of the substantially band-like crystalline silicon films of the silicon islands LD-P and LD-N exists so as to be substantially in the same direction as the crystal direction CGR. A source electrode SD1 and a drain electrode SD2 are respectively formed at positions facing the crystal direction CGR. The direction of the current (channel current) Ich flowing between the source electrode SD1 and the drain electrode SD2 is set in a direction substantially parallel to the crystal direction CGR. Thus, the electron mobility in the channel can be increased by making the crystal direction CGR and the direction of the current Ich the same.

  6 is an enlarged plan view of a portion B in one virtual tile shown in FIG. 4, and FIG. 7 is a sectional view taken along the line CC ′ of FIG. FIG. 8 is a timing chart for explaining the operation of FIG. The configuration and operation of FIGS. 6 and 7 will be described with reference to FIGS. In FIG. 6, reference numerals NT1 and NT2 are N-type thin film transistors, PT1 and PT2 are P-type thin film transistors, and SR1 +, SR1-, SR2 +, SR2- are signal lines from the horizontal shift register HSR sent via the buffer BA, VR + and VR− represent red data signals (red video signals). In FIG. 7, reference numeral SUB1 denotes an active matrix substrate, NC denotes an N-type channel, PC denotes a P-type channel, GI denotes a gate insulating film, L1 denotes an interlayer insulating film, and PASS denotes an insulating protective film.

  At time 1 in FIG. 8, "1" is output to the signal line SR1 +, "-1" is output to the signal line SR1-, "-1" is output to the signal line SR2- at time 2, and to the signal line SR2 +. “1” is output. The red data signal VR + outputs the signal of pixel 1 (polarity +) at time 1 and the signal of pixel 2 (polarity +) at time 2. Similarly, the red data signal VR- outputs the signal of pixel 2 (polarity-) at time 1 and the signal of pixel 1 (polarity-) at time 2. The N-type thin film transistor NT1 is turned on at time 1 and outputs a red data signal VR + to the signal line R1. The P-type thin film transistor PT1 is turned on at time 2 and outputs a red data signal VR− to the signal line R1.

  The N-type thin film transistor NT2 is turned on at time 2 to output a red data signal VR + to the signal line R2, and the P-type thin film transistor PT2 is turned on at time 1 to send the red data signal VR− to the signal line R2. Output. Thus, the signal line R1 outputs polarity + data (pixel signal) at time 1 and polarity − data (pixel signal) at time 2. Further, the signal line R2 outputs polarity-negative data (pixel signal) at time 1 and polarity-positive data (pixel signal) at time 1.

  In the embodiment described above, the virtual tile TL of the substantially band-shaped crystalline silicon film is set for each circuit forming portion of the sampling switch SSW constituting the sampling circuit SAMP. As described above, the sampling switch SSW is configured by an analog switch, and is a part that requires a high definition with a complicated circuit configuration. By forming a thin film transistor by providing a substantially band-shaped crystal silicon film indicated by the virtual tile TL in this circuit portion, a circuit with high electron mobility and improved definition can be realized. As a result, high-speed image display can be realized. Note that the place where the virtual tile is set is not limited to the sampling circuit SAMP described above, but can be applied to an appropriate circuit formation portion in the range SX shown in FIG.

  FIG. 9 is a block diagram similar to FIG. 2 for schematically explaining another embodiment in which the image display device according to the present invention is applied to a liquid crystal display device. In this embodiment, the virtual tile TL is formed in the first latch circuit LT1 and the second latch circuit LT2, the digital-analog converter DAC, and the buffer circuit BA. Thus, in this embodiment, the virtual tiles TL are formed in two or more rows parallel to the x direction. Since other configurations are the same as those in FIG. Here, for ease of explanation, each of the virtual tiles TL is shown in a rough range, but each virtual tile TL has a plurality of virtual tiles having appropriate sizes according to the circuit scale to be applied. Including a block aggregate.

  By providing a substantially band-like crystalline silicon film indicated by the virtual tile TL in these circuit portions, it is possible to increase the electron mobility and improve the definition. As a result, high-definition image display can be realized at high speed. Note that the location where the virtual tile is set is not limited to the above-described portion, and the sampling circuit SAMP can also be included as in FIG. In addition, the virtual tile TL may be set to various sizes including each of the first latch circuit LT1, the second latch circuit LT2, the digital-analog converter DAC, the buffer circuit BA, or a circuit appropriately combined. .

  The size and arrangement of the virtual tiles described in the above embodiments and the size and arrangement of the individual modified regions may be determined in consideration of the built-in pattern of the thin film transistor of each application circuit, for example, a staggered arrangement. Etc. are also possible, and it is not always necessary to stick to the regular arrangement.

  In the above embodiment, the discontinuous reforming region (virtual tile) of the substantially band-shaped crystal silicon film is applied to the driving circuit region DAR1 that forms the driving circuit on the data side. However, the present invention is not limited to this, and scanning is performed. The same applies to the drive circuit region DAR2 or the drive circuit region DAR3 having a precharge circuit.

  Thus, according to the configuration of each of the above embodiments, the drive circuit for driving the pixel portions arranged in a matrix is provided with an active matrix substrate having a high-performance thin film transistor circuit that operates at high mobility. An image display device can be manufactured, and a high-quality image display device can be obtained.

  Next, an embodiment of a method for manufacturing an image display device according to the present invention will be described with reference to FIGS. The manufacturing method described here is an example of manufacturing a CMOS thin film transistor, an N-type thin film transistor is formed by self-aligned GOLDD (Gate Overlapped Light Doped Drain), and a P-type thin film transistor is formed by counter-doping.

  10 to 15 show a series of manufacturing processes, and this series of manufacturing processes will be described with reference to (A) to (N) of FIG. First, as an insulating substrate to be an active matrix substrate, a heat-resistant glass substrate SUB1 having a thickness of about 0.3 mm to 1.0 mm, preferably less deformed and contracted by heat treatment at 400 ° C. to 600 ° C. is prepared. To do. Preferably, an approximately 50 nm thick SiN film and an approximately 100 nm thick SiO film functioning as a thermal and chemical barrier film are continuously and uniformly deposited on the glass substrate SUB1 by a CVD method. An amorphous silicon film ASI is formed on the glass substrate SUB1 by means such as CVD. ... Figure 10 (A)

  Next, the excimer laser beam ELA is scanned in the x direction, the amorphous silicon film ASI is melted and crystallized to modify the entire amorphous silicon film ASI on the glass substrate SUB1 into a polycrystalline silicon film, that is, a polysilicon film PSI. . ... Figure 10 (B)

  Instead of the excimer laser beam ELA, other methods such as crystallization by solid-state pulse laser annealing and a Cat-CVD film that becomes a polysilicon film when a silicon film is formed may be employed.

  A positioning mark MK serving as a target for irradiation positioning of a laser beam SXL such as a pulse modulation laser (described later using a pulse width modulation laser) is formed by photolithography or dry etching. ... Figure 10 (C)

  While referring to the mark MK, the pulse-modulated laser beam SXL is irradiated in a discontinuous manner while selecting a predetermined region while scanning in the x direction. The polysilicon film PSI is modified by this selective irradiation to form a discontinuous modified region (virtual tile silicon film) SPSI of a substantially band-like crystalline silicon film having a grain boundary continuous in the scanning direction. At this time, by covering the drive circuit region DAR3 with the laser light that scans the drive circuit region DAR1 and / or DAR2 in FIG. 1, the drive circuit region DAR3 adjacent to the drive circuit regions DAR1 and DAR2 is also simultaneously virtual tiled. Can be formed. ... Figure 11 (D)

  An island SPSI-L for forming a thin film transistor is formed by processing the discontinuously modified region (silicon film of the virtual tile) SPSI of the substantially band-shaped crystal silicon film by using a photolithography method. ... Figure 11 (E)

  A gate insulating film GI is formed to cover the discontinuous modified region (silicon film of the virtual tile) SPSI island SPSI-L. ... Figure 11 (F)

  Implantation NE for controlling the threshold value is performed in the region where the N-type thin film transistor is formed. At this time, the region for forming the P-type thin film transistor is covered with the photoresist RNE. ... Figure 12 (G)

  Next, an implantation PE for controlling a threshold value is performed in a region where a P-type thin film transistor is formed. At this time, the region for forming the P-type thin film transistor is covered with a photoresist RPE. ... Figure 12 (H)

  On top of this, two layers of metal gate films GT1 and GT2 to be gate electrodes of the thin film transistor are formed by sputtering or CVD. ... Figure 12 (I)

  The formation regions of the metal gate films GT1 and GT2 are covered with a photoresist RN, and the metal gate films GT1 and GT2 are patterned by a photolithography method. At this time, in order to form the LDD region, the upper-layer metal gate film GT2 is side-etched by a required amount and is made to recede from the lower-layer metal gate film GT1. In this state, N type impurities N are implanted using the photoresist RN as a mask to form source / drain regions NSD of the N type thin film transistor. ... Figure 13 (J)

  The photoresist RN is peeled off, and implantation LDD is performed using the metal gate film GT2 as a mask to form an LDD region NLDD of the N-type thin film transistor. ... Figure 13 (K)

  The formation region of the N-type thin film transistor is covered with a photoresist RP, and a P-type impurity P is implanted into the source / drain formation region of the P-type thin film transistor to form the source / drain region PSD of the P-type thin film transistor. ... Figure 14 (L)

  After stripping the photoresist RP and activating impurities by implantation, an interlayer insulating film LI is formed by a CVD method or the like. ... Figure 14 (M)

  A contact hole is formed in the interlayer insulating film LI and the gate insulating film GI by photolithography, and a metal layer for wiring is connected to each source / drain NSD, PSD of the N-type thin film transistor and the P-type thin film transistor through the contact hole. The wiring L is formed. On this, an interlayer insulating film L2 is formed, and further a protective insulating film PASS is formed. ... Figure 14 (N)

  Through the above steps, a CMOS thin film transistor is formed in the discontinuous modified region (silicon film of the virtual tile) SPSI of the substantially band-shaped crystalline silicon film. In general, the N-type thin film transistor is severely deteriorated. If a low-concentration impurity region LDD (Light Doped Drain region) is formed between the channel and the source / drain region, this deterioration is alleviated. GOLDD has a structure in which a gate electrode is covered with a low concentration impurity region. In this case, the performance degradation observed with LDD is alleviated. The deterioration of the P-type thin film transistor is not as severe as that of the N-type thin film transistor, and the low-concentration impurity regions LDD and GOLDD are not usually employed.

  Next, the formation of the discontinuous modified region (silicon film of the virtual tile) of the substantially band-like crystalline silicon film, which is a feature of the present invention, will be described with reference to FIGS. FIG. 16 is an explanatory diagram of a process for forming a discontinuous modified region (virtual tile silicon film) of a substantially band-like crystalline silicon film, where FIG. 16 (a) is a schematic diagram for explaining the process, and FIG. An example of the waveform of the modulation laser, FIG. 9C shows an example of the waveform of the pseudo CW laser.

  The discontinuous modified region (virtual tile) of the substantially band-shaped crystalline silicon film is formed by applying the laser beam shown in FIG. 16B or FIG. 16C to the polysilicon film PSI formed on the buffer layer BFL included in the insulating substrate SUB1. It is obtained by irradiating SXL. The laser beam SXL is irradiated with the pulse-modulated laser beam (b) or the pseudo CW laser beam as shown in (c) at a cycle of 10 ns to 100 ms. The laser light SXL is scanned in the x direction on the polysilicon film PSI as shown in FIG. 16A, shifted in the y direction, and then scanned in the −x direction, so that the scanning directions x, −x A silicon film SPSI having a substantially band-like crystal in the direction is obtained. The insulating substrate SUNB1 has a mark MK for positioning, and the laser beam SXL is scanned using the mark MK as a positioning target. Since the substrate is scanned while intermittently irradiating the laser in this way, the substantially band-like crystal silicon films SPSI can be arranged in a virtual tile shape.

  17A and 17B are explanatory views of the crystal structure of the substantially band-like crystalline silicon film. FIG. 17A is a schematic diagram for explaining the scanning mode of the laser beam SXL, and FIG. 17B is formed by scanning the laser beam SXL. FIG. 6 is a schematic diagram showing a comparison of the difference in crystal structure between a substantially band-like crystalline silicon film SPSI and a polysilicon film PSI remaining in a non-scanned portion. By modifying the polysilicon film PSI by scanning with the laser beam SXL as shown in FIG. 9A, the single crystal extends in a band shape in the scanning direction of the laser beam as shown in FIG. The crystal structure of the substantially band-like crystalline silicon film SPSI is obtained. Reference numeral CB indicates a grain boundary.

  The average grain size of the substantially band-like crystalline silicon film SPSI is about 5 μm in the scanning direction of the laser light SXL and about 0.5 μm in the direction perpendicular to the scanning direction (width between grain boundaries CB). The grain size in the scanning direction is variable depending on conditions such as the energy of the laser beam SXL, the scanning speed, and the pulse width. On the other hand, the average particle diameter of the polysilicon film PSI is about 0.6 μm (0.3 to 1.2 μm). Such a difference in crystal structure causes a large difference in electron mobility when a thin film transistor is formed using the polysilicon film PSI and the substantially band-like crystal silicon film SPSI.

The substantially band-like crystalline silicon film SPSI has the following characteristics. That is,
(A) The main orientation with respect to the surface is {110}.
(B) The main orientation of the plane substantially perpendicular to the carrier moving direction is {100}.
The two orientations (a) and (b) can be evaluated by an electron beam diffraction method or an EBSP (Electron Backscatter Diffraction Pattern) method.
(C) The defect density of the film is smaller than 1 × 10 ¹⁷ cm ⁻³ . The number of crystal defects in the film is a value defined from electrical characteristics or quantitative evaluation of unpaired electrons by electron spin resonance (ESR).

(D) The hole mobility of the film is 50 cm ² / Vs or more and 700 cm ² / Vs or less.
(E) The thermal conductivity of the film is temperature dependent and exhibits a maximum value at a certain temperature. The thermal conductivity rises once when the temperature rises, and shows a maximum value of 50 W / mK or more and 100 W / mK or less. In the high temperature region, the thermal conductivity decreases with increasing temperature. The thermal conductivity is a value evaluated and defined by the 3 omega method.
(F) voted Raman scattering spectroscopy of thin film, the Raman shift is defined, 512cm ^-1 or more and 518 cm ^-1 or less.

(G) The distribution of the Σ value of the crystal grain boundary of the film has a maximum value at Σ11 and is distributed in a Gaussian shape. The Σ value is a value measured by an electron diffraction method or an EBSP (Electron Backscatter Diffraction Pattern method).
(H) The optical constant of the film is a region that satisfies the following conditions. The refractive index n at a wavelength of 500 nm is 2.0 or more and 4.0 or less, and the attenuation coefficient k is 0.3 or more and 1 or less. Furthermore, the refractive index n at a wavelength of 300 nm is 3.0 or more and 4.0 or less, and the attenuation coefficient k is 3.5 or more and 4 or less. The optical constant is a value measured by a spectroscopic ellipsometer.

  FIG. 18 is an explanatory diagram of the difference in electron mobility in the channel of the thin film transistor due to the difference in the crystal structure of the silicon film. FIG. 4A shows the channel structure of the thin film transistor and the relationship between the grain boundary CB of the silicon film SI in the channel portion and the electron transfer, and FIG. 4B shows the grain boundary where the current flowing between the source SD1 and the drain SD2 crosses. The relationship between number and electron mobility is shown. When the silicon film SI is the polysilicon film PSI, the number of grain boundaries where the current crosses from the drain SD2 to the source SD1 is large, and when the silicon film SI is the substantially band-like crystalline silicon film SPSI, a large single crystal exists in the growth direction. There are few grain boundaries to cross. This relationship is shown in FIG.

The average number of transverse grain boundaries C is expressed by C = ΣNi / j, where the width of the channel is divided into j in the current direction and the number of grain boundaries crossing in the direction of current flow is Ni. In FIG. 18B, the horizontal axis represents the average transverse grain boundary number, and the vertical axis represents the electron mobility (cm ² / V · s) and its reciprocal (V · s / cm ² ). Thus, by disposing the source SD1 and the drain SD2 so that a current flows in the crystal growth direction of the substantially band-shaped crystalline silicon film SPSI constituting the channel of the thin film transistor, the electron mobility becomes extremely large. That is, the operation speed of the thin film transistor is increased. Therefore, the thin film transistor itself can be finely formed, and the wirings R1, G1, B1, R2, G2, and B2 can be formed at a narrow pitch with respect to the pixel pitch as described with reference to FIG. As a result, a large space is generated between circuits formed using virtual tiles. It is also possible to use this space as a formation space for other wiring or the like.

  FIG. 19 is a configuration diagram illustrating an example of a laser beam irradiation apparatus. In this irradiation apparatus, a glass substrate SUB1 on which a polysilicon film PSI is formed is placed on a driving stage XYT in the xy directions, and alignment is performed using a reference position measuring camera CM. The reference position measurement signal POS is input to the control device CRL, fine adjustment of the irradiation position is performed based on the control signal CS input to the drive equipment MD, and the stage XYT is moved at a predetermined speed in one direction (in FIG. 1). Scan in the x direction). The polysilicon film PSI is irradiated with laser light SXL from the irradiation equipment LU in synchronization with such scanning, and is reformed into a substantially band-like crystalline silicon film SPSI.

  In the irradiation equipment LU, as an example, an optical system HOS such as a continuous wave (CW) solid-state laser LS (laser diode) excitation oscillator, a homogenizer, an EO modulator for modulating a pulse width, a reflection mirror ML, and a condenser lens system LZ A desired irradiation beam can be formed by arranging. The irradiation time and irradiation intensity of the laser light SXL are adjusted by the ON-OFF signal SWS and the control signal LEC from the control device CRL.

  FIG. 20 is a plan view for explaining an example of a virtual tile layout. In this arrangement example, the virtual tiles TL are arranged in a plurality of columns in the drive circuit area DAR1 described in FIG. The virtual tiles TL can be arranged in one row, two or more rows, or a staggered pattern according to circuit pulses to be created. In this example, there are three rows (or three stages). The size of each virtual tile TL is such that the length w in the x direction is 20 μm or more and 1 mm or less, the width h in the y direction is 20 μm or more and 1 mm or less, and the distance d between adjacent virtual tiles in the x direction is 3 μm or more. The interval p is 3 μm or more. This arrangement size is limited by the power of the laser and the size at which a high-quality crystal can be stably grown.

  FIG. 21 is an explanatory view of a laser irradiation process example using the irradiation apparatus of FIG. In FIG. 21, the insulating substrate is simply referred to as a substrate. First, in order to irradiate the insulating substrate on which the polysilicon film is formed with the laser beam SXL, the apparatus power supply is turned on and the laser oscillator is turned on. An insulating substrate is set on the drive stage XYT and fixed with a vacuum chuck. Preparation of the insulating substrate is completed by adjusting the X-axis, Y-axis, and θ-axis (rotation direction on the XY plane) to the specified values using the positioning mark of the insulating substrate as a target.

  On the other hand, various conditions are input to the irradiation apparatus and confirmed. The condition input items are laser output (ND filter adjustment, etc.), set position of crystallization position (on drive stage XYT), crystallization distance (length of crystal growth direction of virtual tile), interval (interval of virtual tile), For example, the number (the number of virtual tiles to be created), the adjustment of the slit width on the laser beam path, and the setting of an objective lens. The crystallization distance, interval and number are set in the EO modulator. The confirmation items are a laser beam profiler, a power monitor, a laser beam irradiation position, and the like.

  After the preparation of the insulating substrate is completed and the condition input and confirmation are taken, the surface height of the insulating substrate is measured, the autofocus mechanism is activated, and the laser beam is irradiated. The autofocus mechanism is corrected by laser light irradiation, and the surface height of the insulating substrate is controlled. Further, while the laser beam irradiation is continued, the scanning distance and irradiation position of the insulating substrate are fed back to the condition input side.

  After completing the laser beam irradiation process in a predetermined region, the vacuum chuck is turned off and the insulating substrate is taken out from the drive stage XYT. Thereafter, the next insulating substrate is set on the drive stage XYT, and the above operation is repeated as many times as necessary. When the laser irradiation processing of all necessary insulating substrates is completed, the laser oscillator is turned off, the apparatus power supply is turned off, and the process ends.

  FIG. 22 is an explanatory diagram of the virtual tile forming operation of the substantially band-shaped crystalline silicon film SPSI for each individual insulating substrate on the multi-faceted large-sized material insulating substrate. In FIG. 22, reference numeral M-SUB is a large-sized material insulating substrate, and a large number of active matrix substrates SUB1 of individual image display devices are formed on the large-sized material insulating substrate M-SUB. Here, 8 × 6 = 48 sheets are shown, but it goes without saying that the present invention is not limited to this. After alignment with the mark MK as a target with respect to the drive circuit region of the large-size material insulating substrate M-SUB, the laser beam is reciprocally scanned as indicated by an arrow SDS in the drawing. Here, a required virtual tile can be formed on a large-sized material insulating substrate M-SUB in a short time by scanning three laser beams in parallel.

  FIG. 23 is a plan view of one active matrix substrate for explaining an example of the position of the virtual tile formed in FIG. 22. FIG. 23 (a) is an overall view, and FIG. 23 (b) is the same view (a). It is an enlarged view of the arrow A part. In this example, blocks of a plurality of virtual tiles TL are arranged in a row on one side in the x direction forming the drive circuit area DAR1 for data signals of the active matrix substrate SUB1. In this case, the virtual tile is the entire area indicated by reference numeral SX in FIG. 2 or FIG. 9, or the sampling circuit SAMP portion in FIG. 2, the portions of the latch circuits LT1 and LT2 in FIG. 9, and the digital-analog converter DAC and buffer circuit. A plurality of BA are provided, which are divided into blocks. The individual modified regions that make up the virtual tile are similarly arranged. It should be noted that the size and position of the virtual tile block and the individual modified regions in FIG. 8B are easy to understand the present invention and are different from the actual circuit size and position.

  FIG. 24 is an enlarged view similar to FIG. 23B for explaining another arrangement of the virtual tiles. The blocks of the virtual tile TL are arranged in two rows parallel to the x direction as shown in FIG. 5A, or are arranged in three rows staggered parallel to the x direction as shown in FIG. Note that the size and interval of each block can be made variable in accordance with the applied circuit structure. In addition, the arrangement | sequence of each modification | reformation area | region which comprises a block can also be made into multiple arrangement | sequence or a staggered arrangement | sequence.

  25 and 26 are plan views of one active matrix substrate for explaining another example of the position of the virtual tile. In FIG. 25, virtual tiles are applied to the drive circuit areas DAR1 and DAR3 described in FIG. In FIG. 26, virtual tiles are applied to the drive circuit areas DAR1 and DAR3 described in FIG. 1 and the scan drive circuit area DAR2 formed on one side extending in the y direction of the active matrix substrate SUB1. The arrangement of individual virtual tiles and blocks is the same as that described with reference to FIGS.

  Next, positioning marks for forming virtual tiles on an insulating substrate (active matrix substrate) will be described. FIG. 27 is an explanatory diagram of a first example of marking for positioning on the active matrix substrate SUB1 and a laser irradiation process using the mark as a target. In this example, a positioning mark MK is formed on the silicon film SI formed on the active matrix substrate SUB1 by a photolithography method (P-1), and this mark MK is used as a reference during subsequent irradiation with the continuous pulse laser SLX. Positioning (alignment) is taken as (P-2). Similarly, the substantially band-like crystalline silicon film SPSI modified by the irradiation of the continuous pulse laser SLX is processed into an island SPSI-L using the mark MK as a reference (P-3). The mark MK may be formed at the stage of the amorphous silicon film ASI or may be formed at the stage of the polysilicon film.

  FIG. 28 is an explanatory diagram of a second example of the positioning mark on the active matrix substrate SUB1 and the irradiation process of the laser beam using this mark as a target. In this example, after the polysilicon film PSI is formed on the active matrix SUB1 (P-1), when the laser SLX is irradiated on the polysilicon film PSI, the positioning mark MK is formed by the laser SLX. (P-2). When the island SPSI-L is subsequently formed, the mark MK is used for positioning (P-3).

  There is a difference in the reflectance of visible light between the polysilicon film PSI and the substantially band-like crystalline silicon film SPSI. This difference can be used as a positioning target. Further, the polysilicon film PSI and the substantially band-like crystalline silicon film SPSI are different in height due to the size of the crystal. The step of the crystal grain boundary at the mark MK where the substantially band crystallizes can be used as a target. The polysilicon film at the mark MK portion can be removed by laser ablation to form the mark MK. This method of forming the mark MK by laser ablation has the advantage that the photolithography process for forming the mark MK can be omitted.

  FIG. 29 is an explanatory diagram of a third example of positioning marking on the active matrix substrate SUB1 and a laser light irradiation process using this mark as a target. In this example, before the silicon film is formed on the active matrix substrate SUB1, the mark MK is formed in advance on the glass substrate or the base film by an etching method or mechanical means (P-1). A polysilicon film PSI is formed on the active matrix substrate SUB1, and a laser beam SLX is irradiated with the mark MK as a reference to form a substantially band-like crystalline silicon film SPSI (P-2). When the island SPSI-L is subsequently formed, the mark MK is used for positioning (P-3).

As described above, according to the present embodiment, the probability that the current between the source and the drain crosses the grain boundary can be reduced by modifying the polysilicon film into a larger crystal and arranging it in the crystal growth direction. As a result, it is possible to improve the operation speed of the thin film transistor and obtain the best thin film transistor circuit. A thin film transistor circuit using a semiconductor film of a substantially band-like crystalline silicon film can be disposed in the drive circuit portion of the image display device. The performance of the thin film transistor obtained in this example is that, for example, when producing an N-channel MIS transistor, the field effect mobility is about 300 cm ² / V · s or more and the variation in threshold voltage is suppressed to ± 0.2 V or less. Therefore, a display device using an active matrix substrate that operates with high performance and high reliability and excellent uniformity among devices can be manufactured.

  In this embodiment, a P-channel MIS transistor can also be manufactured by boron implantation that provides hole carriers instead of phosphorus ion implantation that imparts electron carriers. Further, the above-described CMOS type circuit can be expected to improve frequency characteristics, and is suitable for high-speed operation.

  FIG. 30 is an exploded perspective view illustrating the configuration of a liquid crystal display device as a first example of the image display device of the present invention. FIG. 31 is a cross-sectional view taken along the line ZZ in FIG. This liquid crystal display device is manufactured using the above-described active matrix substrate. 30 and 31, reference numeral PNL is a liquid crystal cell in which liquid crystal is sealed in a bonding gap between the active matrix substrate SUB1 and the color filter substrate SUB2, and polarizing plates POL1 and POL2 are laminated on the front and back sides. Reference numeral OPS is an optical compensation member made of a diffusion sheet or prism sheet, GLB is a light guide plate, CFL is a cold cathode fluorescent lamp, RFS is a reflection sheet, LFS is a lamp reflection sheet, SHD is a shield frame, and MDL is a mold case. is there.

  A liquid crystal alignment film layer is formed on the active matrix substrate SUB1 having the structure of any of the above-described embodiments, and an alignment regulating force is applied thereto by a technique such as rubbing. After the sealant is formed around the pixel area AR, the color filter substrate SUB2 on which the alignment film layer is similarly formed is disposed opposite to the gap, a liquid crystal is sealed in the gap, and the sealing agent sealing port is sealed. Close with a stopper. A liquid crystal display device is manufactured by laminating polarizing plates POL1 and POL2 on the front and back of the liquid crystal cell PNL thus configured, and mounting a backlight composed of the light guide plate GLB and the cold cathode fluorescent lamp CFL via the optical compensation member OPS. To do. Note that data and timing signals are supplied to the driving circuit around the liquid crystal cell via the flexible printed boards FPC1 and FPC2. The reference code PCB is mounted between an external signal source and each of the flexible printed circuit boards FPC1 and FPC2 with a timing converter for converting a display signal input from the external signal source into a signal format to be displayed on a liquid crystal display device.

  The liquid crystal display device using the active matrix substrate of this embodiment is suitable for high-speed operation because it has excellent current driving capability by disposing the above-described excellent polysilicon thin film transistor circuit in its pixel circuit. Further, since the variation in the threshold voltage is small, the liquid crystal display device can be provided at low cost with excellent image quality uniformity.

  In addition, an organic EL display device can be manufactured using the active matrix substrate of this embodiment. FIG. 32 is an exploded perspective view illustrating a configuration example of an organic EL display device as a second example of the image display device of the present invention. FIG. 33 is a plan view of an organic EL display device in which the components shown in FIG. 32 are integrated. An organic EL element is formed on the pixel electrode included in the active matrix substrate SUB1 in any of the embodiments described above. The organic EL element is composed of a laminate in which a hole transport layer, a light emitting layer, an electron transport layer, a cathode metal layer, and the like are deposited sequentially from the surface of the pixel electrode. A sealing material is disposed around the pixel region PAR of the active matrix substrate SUB1 on which such a laminated layer is formed, and sealed with a sealing substrate SUBX or a sealing can.

  This organic EL display device supplies a display signal from an external signal source to the drive circuit region DDR through a printed circuit board PLB. An interface circuit chip CTL is mounted on the printed circuit board PLB. Then, the shield frame SHD as the upper case and the lower case CAS are integrated to form an organic EL display device.

  In the active matrix drive for organic EL display devices, the organic EL element is a current-driven light emission method, so the use of a high-performance pixel circuit is essential to provide a high-quality image. It is desirable to use it. A thin film transistor circuit formed in the driver circuit region is also essential for high speed and high definition. The active matrix substrate SUB1 of this embodiment has high performance that satisfies such requirements. The organic EL display device using the active matrix substrate manufactured by the manufacturing method of this embodiment is one of the display devices that maximize the features of this embodiment.

  The manufacturing method of the present invention is not limited to the active matrix substrate of the image display device described above, and the manufacturing method of the present invention is limited to the configurations described in the claims and the configurations described in the embodiments. Instead, various modifications can be made without departing from the technical idea of the present invention, and for example, the invention can be applied to the manufacture of various semiconductor devices.

It is a top view for demonstrating typically the liquid crystal display device as an example of the image display apparatus manufactured by applying the manufacturing method by this invention. FIG. 2 is a block diagram illustrating a circuit configuration example of a data driving circuit portion in FIG. 1. It is a block diagram of the sampling switch part which comprises the sampling circuit in FIG. FIG. 4 is an enlarged plan view illustrating one configuration of a sampling switch circuit formed in the virtual tile illustrated in FIG. 3. FIG. 5 is a schematic diagram of a channel portion of a thin film transistor (TFT) showing a crystal direction of a substantially band-like crystalline silicon film by further enlarging the main part of FIG. 4. FIG. 5 is an enlarged plan view of a portion B in one virtual tile illustrated in FIG. 4. FIG. 7 is a cross-sectional view taken along line C-C ′ of FIG. 6. FIG. 7 is a timing chart for explaining the operation of FIG. 6. FIG. 5 is a block diagram similar to FIG. 2 for schematically explaining another embodiment in which the image display device according to the present invention is applied to a liquid crystal display device. It is explanatory drawing of the process explaining one Example of the manufacturing method of the image display apparatus of this invention. It is explanatory drawing of the process following FIG. 10 explaining one Example of the manufacturing method of the image display apparatus of this invention. It is explanatory drawing of the process following FIG. 11 explaining one Example of the manufacturing method of the image display apparatus of this invention. It is explanatory drawing of the process following FIG. 12 explaining one Example of the manufacturing method of the image display apparatus of this invention. It is explanatory drawing of the process following FIG. 13 explaining one Example of the manufacturing method of the image display apparatus of this invention. It is explanatory drawing of the process following FIG. 14 explaining one Example of the manufacturing method of the image display apparatus of this invention. It is explanatory drawing of the formation process of the discontinuous modification area | region (virtual tile) of a substantially strip | belt-shaped crystalline silicon film. It is explanatory drawing of the crystal structure of a substantially strip-shaped crystalline silicon film. It is explanatory drawing of the difference in the electron mobility in the channel of a thin-film transistor resulting from the difference in the crystal structure of a silicon film. It is a block diagram explaining an example of the irradiation apparatus of a laser beam. It is a top view explaining an example of the layout of a virtual tile. It is explanatory drawing of the example of a laser irradiation process using the irradiation apparatus of FIG. It is explanatory drawing of virtual tile formation operation of the substantially strip | belt-shaped crystal | crystallization silicon | silicone film | membrane SPSI with respect to each separate insulation board | substrate on the multi-surfaced large sized material insulation board | substrate. It is a top view of one active matrix substrate explaining an example of the position of the virtual tile formed in FIG. FIG. 24 is an enlarged view similar to FIG. 23B illustrating another arrangement of virtual tiles. It is a top view of one active matrix board | substrate explaining the other example of the position of a virtual tile. It is a top view of one active matrix board | substrate explaining the further another example of the position of a virtual tile. It is explanatory drawing of the 1st example of the marking process for the positioning to an active matrix substrate, and the irradiation process of the continuous pulse laser which made this mark the target. It is explanatory drawing of the 2nd example of the irradiation process of the continuous pulse laser which made the mark for positioning to the active-matrix board | substrate SUB1, and this mark the target. It is explanatory drawing of the 3rd example of the irradiation process of the continuous pulse laser which made the mark for positioning to the active-matrix board | substrate SUB1, and this mark the target. 1 is an exploded perspective view illustrating a configuration of a liquid crystal display device as a first example of an image display device of the present invention. It is sectional drawing cut | disconnected in the ZZ line direction of FIG. It is an expansion | deployment perspective view explaining the structural example of the organic electroluminescence display as a 2nd example of the image display apparatus of this invention. It is a top view of the organic electroluminescence display which integrated the component shown by FIG. It is explanatory drawing of the crystallization method of the amorphous silicon film by scanning a general excimer pulse laser beam irradiation. FIG. 35 is a partial plan view of a laser light irradiation unit in FIG. 34 and a main part plan view illustrating a configuration example of a thin film transistor unit.

Explanation of symbols

SUB1... Active matrix substrate, PAR... Pixel area, dar1, dar2, dar3... Drive circuit, GDR1, GDR2 ... Scan circuit, SUB2 ... Color filter substrate, CPADQ ... Pad, HSR ... Horizontal shift register, LT1 ... First latch circuit, LTS ... ... Second latch circuit, DAC ... Digital-analog converter, BA ... Buffer circuit, SAMP ... Sampling circuit, VSR ... Vertical shift register, R1, G1, B1, R2, G2, B2 ... Signal lines, TL ... Virtual tiles, ELA ... Excimer laser light, SXL ... Pulse modulated laser light or Similar CW laser light, SPSI · · · · substantially strip crystalline silicon film discontinuous converted regions (virtual tile silicon film), ASI · · · · amorphous silicon film, PSI · · · · polysilicon film.

Claims (22)

Forming a semiconductor film over an insulating substrate;
Scanning the semiconductor film while irradiating laser light of a continuous wave laser to form a substantially band-like crystal in which a semiconductor crystal grows in a substantially band-like manner at a plurality of locations of the semiconductor film;
Forming a thin film transistor having the substantially band-shaped crystal;
The method includes a step of dividing the insulating substrate into a plurality of active matrix substrates by cutting the insulating substrate so as not to cross any portion irradiated with the laser light of the continuous wave laser. Manufacturing method of image display apparatus.   The method for manufacturing an image display device according to claim 1, wherein the laser beam of the continuous wave laser is scanned by moving the insulating substrate.   The method of manufacturing an image display device according to claim 1, wherein the semiconductor film includes silicon.   2. The method of manufacturing an image display device according to claim 1, wherein the laser light emitted from the continuous wave laser is scanned while being pulse-modulated to irradiate the laser light while avoiding a cut portion. .   The method of manufacturing an image display device according to claim 1, wherein the laser beam is reciprocally scanned.   The method for manufacturing an image display device according to claim 1, wherein a plurality of the laser beams are scanned in parallel.   2. The method for manufacturing an image display device according to claim 1, wherein the semiconductor film is irradiated with the laser light of the continuous wave laser before patterning the semiconductor film.   The method for manufacturing an image display device according to claim 1, wherein the step of forming the semiconductor film on the insulating substrate is a step of forming an amorphous semiconductor film.   2. The method for manufacturing an image display device according to claim 1, wherein the step of forming the semiconductor film on the insulating substrate is a step of forming a polycrystalline semiconductor film.   2. The method of manufacturing an image display device according to claim 1, further comprising a step of forming a positioning mark by irradiating the semiconductor film with the continuous wave laser.   The method for manufacturing an image display device according to claim 10, wherein when the semiconductor film on which the substantially band-like crystal is formed is patterned, the positioning is performed by the positioning mark. Forming a semiconductor film over an insulating substrate;
Scanning the semiconductor film while irradiating a laser beam of a quasi-continuous oscillation laser to form a substantially band-shaped crystal in which a semiconductor crystal grows in a substantially band shape at a plurality of locations of the semiconductor film;
Forming a thin film transistor having the substantially band-shaped crystal;
A step of dividing the insulating substrate into a plurality of active matrix substrates by cutting the insulating substrate so that none of the portions irradiated with the laser light of the pseudo continuous wave laser is traversed. Manufacturing method of an image display device.   13. The method for manufacturing an image display device according to claim 12, wherein the laser beam of the pseudo continuous wave laser is scanned by moving the insulating substrate.   The method of manufacturing an image display device according to claim 12, wherein the semiconductor film includes silicon.   13. The image display device according to claim 12, wherein the laser light emitted from the pseudo continuous wave laser is scanned while being pulse-modulated to irradiate the laser light while avoiding a cut portion. Method.   The method for manufacturing an image display device according to claim 12, wherein the laser beam is reciprocally scanned.   The method for manufacturing an image display device according to claim 12, wherein a plurality of the laser beams are scanned in parallel.   13. The method for manufacturing an image display device according to claim 12, wherein the laser light of the pseudo continuous wave laser is irradiated to the semiconductor film before patterning the semiconductor film.   The method for manufacturing an image display device according to claim 12, wherein the step of forming the semiconductor film on the insulating substrate is a step of forming an amorphous semiconductor film.   13. The method for manufacturing an image display device according to claim 12, wherein the step of forming the semiconductor film on the insulating substrate is a step of forming a polycrystalline semiconductor film.   13. The method for manufacturing an image display device according to claim 12, further comprising a step of forming a positioning mark by irradiating the semiconductor film with the pseudo continuous wave laser. 22. The method for manufacturing an image display device according to claim 21, wherein positioning is performed by the positioning mark when patterning the semiconductor film on which the substantially band-like crystal is formed.

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