CN104300002A - Thin film transistor and manufacturing method and photoetching process thereof - Google Patents

Abstract

The present invention provides a thin film transistor, a manufacturing method thereof, and a photolithography process. The photolithography process uses a half-grayscale mask for exposure, and after exposure and development, sequentially removes The etching is completed for the film layer A, the film layer B corresponding to the first region of the half-grayscale mask, and the film layer A corresponding to the third region of the half-grayscale mask. This kind of photolithography process can meet the etching requirements of film layer A and film layer B only through one exposure through the half gray scale mask, and can reduce the process of photolithography process, so as to achieve the goal of simplifying the photolithography process. The purpose is to reduce the production cost. When the thin film transistor is manufactured by using this photolithography process, the manufacturing process of the thin film transistor can be simplified from six photolithography steps to four photolithography steps, which simplifies the manufacturing method of the thin film transistor and reduces the manufacturing cost of the thin film transistor.

Description

A kind of thin film transistor and its manufacturing method, photolithography process

technical field

The invention belongs to the field of manufacturing semiconductor devices, and in particular relates to a thin film transistor, a manufacturing method thereof, and a photolithography process.

Background technique

In the process of manufacturing semiconductor devices, photolithography technology is generally involved. Photolithography technology is the basis for constructing a film layer or circuit layer with a preset pattern on a flat substrate.

Photolithography technology includes many steps and processes in the actual production process: first, a complete film layer or circuit layer is formed on a flat substrate, and a photoresist layer is formed on the surface of the complete film layer or circuit layer; followed by exposure Operation, let the strong light shine on the substrate through a patterned hollow mask (MASK). If the photoresist layer is a positive photoresist layer, the part of the photoresist layer that is irradiated by the light will deteriorate; The next step is to clean the substrate with a corrosive liquid, and the deteriorated photoresist layer will be removed, exposing the underlying film layer or circuit layer, while the film layer or circuit layer in other areas will not be damaged under the protection of the undeteriorated photoresist layer. It will be affected; then etching is performed to remove part of the film layer or circuit layer that does not have a photoresist layer on the surface; finally, the remaining photoresist layer is removed by cleaning to complete the production of the film layer or circuit layer on the surface of the substrate.

However, in the process of applying the existing photolithography process, each time a film layer or circuit layer is produced, one exposure and one etching are required. For today's semiconductor-related devices, because the structure of the device is relatively complex, including more film layers or circuit layer structures with patterns, it is necessary to perform multiple photolithography processes and undergo multiple exposure and etching processes. The production process is complicated.

Contents of the invention

In view of this, the present invention provides a thin film transistor, a manufacturing method thereof, and a photolithography process. When a semiconductor device is manufactured using the photolithography process provided by the present invention, the manufacturing process can be reduced, and the manufacturing difficulty and production cost of the device can be reduced.

In order to achieve the above object, the embodiment of the present invention provides the following technical solutions:

A photolithography process, comprising: providing a substrate, a surface of the substrate is formed with a film layer A and a film layer B, wherein the film layer B is located between the substrate and the film layer A; A photoresist layer is formed on the surface; the photoresist layer is exposed using a half-grayscale mask, wherein the half-grayscale mask includes a first region, a second region and a third region, and the The light transmittance of the first region and the second region is opposite, and the third region is a semi-transparent region; developing removes the photoresist layer corresponding to the first region of the half-grayscale mask plate, and thins the half-grayscale The photoresist layer corresponding to the third area of the mask; remove the film layer A corresponding to the first area of the half-grayscale mask; remove the film layer B and half-gray corresponding to the first area of the half-grayscale mask The photoresist layer corresponding to the third region of the half-gray-scale mask, and thin the photoresist layer corresponding to the second region of the half-gray-scale mask; remove the film layer corresponding to the third region of the half-gray-scale mask A: Remove the photoresist layer corresponding to the second region of the half-gray scale mask to complete the photolithography.

A method for manufacturing a thin film transistor, using the above-mentioned photolithography process to manufacture gates and transparent electrodes of the thin film transistor, comprising: providing a substrate; forming silicon islands on the surface of the substrate; forming silicon islands on the substrate An insulating layer is formed on the surface, and the insulating layer covers the substrate and the silicon island; a transparent electrode layer and a gate layer are formed on the surface of the insulating layer, wherein the transparent electrode layer is located between the insulating layer and the between the gate layers; forming a photoresist layer on the surface of the gate layer; exposing the photoresist layer using a half-grayscale mask, wherein the half-grayscale mask includes a first region , the second area and the third area, and the light transmission properties of the first area and the second area are opposite, and the third area is a semi-transmissive area; the first area corresponding to the first area of the half-gray scale mask plate is removed by development photoresist layer, and thin the photoresist layer corresponding to the third region of the half-grayscale mask plate; remove the grid layer corresponding to the first region of the half-grayscale mask plate; remove the half-grayscale mask plate The transparent electrode layer corresponding to the first region and the photoresist layer corresponding to the third region of the half-grayscale mask plate, and thinning the photoresist layer corresponding to the second region of the half-grayscale mask plate; remove the half-grayscale The grid layer corresponding to the third area of the mask plate; removing the photoresist layer corresponding to the second area of the half-gray scale mask plate to form a transparent electrode and grid; in the transparent electrode, grid and insulating layer A passivation layer is formed on the surface, and a via hole is formed in the passivation layer; a source electrode and a drain electrode are formed on the surface of the substrate on which the passivation layer is formed, and the source electrode passes through the via hole in the passivation layer The drain is in contact with the surface of the silicon island, the drain is in contact with the silicon island and the transparent electrode through the via hole in the passivation layer, and the fabrication of the thin film transistor is completed.

Preferably, when the photoresist layer is a positive photoresist layer, the first area of the half-gray scale mask is a light-transmitting area, and the second area is an opaque area.

Preferably, when the photoresist layer is a negative photoresist layer, the first region of the half-gray-scale mask is an opaque region, and the second region is a light-transmitting region.

Preferably, the method for removing the gate layer corresponding to the first region of the half-gray scale mask is wet etching.

Preferably, the transparent electrode layer corresponding to the first region of the half-grayscale mask and the photoresist layer corresponding to the third region of the half-grayscale mask are removed, and the second region of the half-grayscale mask is thinned The method for the corresponding photoresist layer is dry etching.

Preferably, the method for removing the gate layer corresponding to the third region of the half-gray scale mask is wet etching.

Preferably, when the thin film transistor is a polysilicon thin film transistor, the method for forming silicon islands on the surface of the substrate includes: forming a polysilicon layer on the surface of the substrate; etching the polysilicon layer by photolithography to form polysilicon islands.

Preferably, when the thin film transistor is a polysilicon thin film transistor, the method for forming silicon islands on the surface of the substrate includes: forming an amorphous silicon layer on the surface of the substrate; etching the amorphous silicon layer by photolithography, forming amorphous silicon islands; laser processing the amorphous silicon islands to crystallize the amorphous silicon islands into polycrystalline silicon islands.

A thin film transistor manufactured according to the above manufacturing method, the gate and transparent electrode of the thin film transistor are completed by one photolithography, and the thin film transistor is formed by four photolithography. Compared with the prior art, the above-mentioned technical solution has the following advantages:

The photolithography process provided by the present invention only needs to be exposed once to complete the photolithography of the two film layer structures at the same time, which specifically includes: firstly using a half-gray scale mask to expose the photoresist layer, after exposure , the photoresist layer corresponding to the first region of the half-grayscale mask will completely deteriorate, the photoresist layer corresponding to the second region of the half-grayscale mask will not be affected, and due to the half-grayscale The third area of the mask is a semi-transparent area, and only a certain thickness of the surface of the photoresist layer corresponding to the third area of the half-gray scale mask is deteriorated.

Then develop, and develop will remove the deteriorated photoresist layer, that is, develop will thin the photoresist layer corresponding to the third region while completely removing the photoresist layer corresponding to the first region of the half-gray scale mask. glue layer. Finally, remove film layer A corresponding to the first region of the half-grayscale mask, film layer B corresponding to the first region of the half-grayscale mask, and photoresist corresponding to the third region of the half-grayscale mask layer and the film layer A corresponding to the third region of the half-grayscale mask.

To sum up, the photolithography process provided by the present invention can meet the etching requirements for film layer A and film layer B only through one exposure through a half-gray scale mask. Moreover, in the subsequent process, the transparent electrode layer corresponding to the first region of the half-grayscale mask and the photoresist layer corresponding to the third region of the half-grayscale mask can be removed at the same time, and the thickness of the half-grayscale mask can be reduced. The photoresist layer corresponding to the second region of the diaphragm can reduce the manufacturing process of the photolithography process, thereby achieving the purpose of simplifying the photolithography process and reducing the production cost.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

1 to 6 are schematic diagrams of the manufacturing method of the existing thin film transistor;

7 to 14 are schematic diagrams of a photolithography process provided by Embodiment 1 of the present invention;

FIG. 15 is a flow chart of a manufacturing method of a thin film transistor provided in Embodiment 2 of the present invention;

16 to 27 are schematic diagrams of a manufacturing method of a thin film transistor provided by Embodiment 2 of the present invention.

Detailed ways

As mentioned in the background art section, the manufacturing process of semiconductor devices using the existing photolithography process is relatively complicated.

Taking the manufacturing method of thin film transistors as an example, the existing manufacturing process of thin film transistors requires six photolithography processes, as shown in Figures 1-6, including:

As shown in FIG. 1 , a substrate 101 is provided, and silicon islands 102 are formed on the surface of the substrate 101 by first photolithography;

As shown in FIG. 2, after the insulating layer 103 is formed on the surface of the substrate 101 with the silicon island 102 formed, a gate 104 and a common electrode 105 are formed on the surface of the insulating layer 103 through a second photolithography process;

As shown in FIG. 3, after the first passivation layer 106 is formed on the surface of the insulating layer 103 formed with the gate 104 and the common electrode 105, a third passivation layer is formed in the first passivation layer 106 through a third photolithography process. contact hole 107;

As shown in FIG. 4, a source electrode 108 and a drain electrode 109 are formed in the contact hole 107 of the first passivation layer 106 through a fourth photolithography process;

As shown in FIG. 5, a second passivation layer 1010 is formed on the surface where the source electrode 108 and the drain electrode 109 are formed, and a via hole 1011 is formed in the second passivation layer 1010 through a fifth photolithography process;

As shown in FIG. 6 , a pixel electrode 1012 is formed on the surface of the second passivation layer 1010 through the sixth photolithography process.

The inventors have found that since the existing photolithography process corresponds to one exposure and one photolithography process, in the process of manufacturing thin film transistors using the existing photolithography process, due to the complex structure of the thin film transistor, the composition of the thin film transistor There are many film layer structures, so in the manufacturing process shown in Figures 1 to 6, a photolithography process is required for each layer of structure, and a total of six photolithography processes are required to manufacture the entire thin film transistor, that is, six photolithography processes are required respectively. Exposure and six etching processes, the production method is complicated.

In particular, for the most common thin film transistor (Thin Film Transistor, referred to as TFT), the existing thin film transistor production process needs to apply multiple photolithography processes, that is, the existing thin film transistor production needs to undergo multiple exposures And etching, the process is more, the production cost is higher.

The inventors found that since the photolithography process includes exposure and etching, the photolithography process can be simplified from two aspects of exposure and etching. In particular, for the exposure step in the photolithography process, the exposure can be performed by introducing a half-grayscale mask. The half-grayscale mask includes a transparent area, an opaque area and a semi-transparent area, and the semi-transparent area The light transmittance can be changed according to the needs. Therefore, after exposure and development using a half-gray scale mask, part of the photoresist layer is completely removed, and part of the photoresist layer is completely retained, while the light corresponding to the semi-transparent area The thickness of the resist layer is reduced. Afterwards, when performing the etching process, the film layer A whose surface photoresist layer has been completely removed is first etched, and then the film layer B on which the film layer A does not exist on the surface is removed by the etching process, and at the same time After thinning the photoresist layer, finally remove the film layer A corresponding to the semi-transparent area, and perform stripping, and clean the remaining photoresist layer. In this way, the etching of two film layers can be completed through one exposure, that is, the etching of two film layers or circuit layers can be completed simultaneously through one photolithography process.

The inventors have further researched and found that, for the manufacturing process of thin film transistors, which generally use etching technology, the above-mentioned photolithography process can be introduced to perform etching to simplify the manufacturing process. Considering the structure and manufacturing method of the existing thin film transistor, what can be realized through the above photolithography process is the fabrication of gate and transparent electrode, reducing the six photolithography processes for manufacturing thin film transistors to four photolithography processes, and realizing four photolithography processes. The sub-lithography process completes the fabrication of the thin film transistor and simplifies the fabrication process of the thin film transistor.

Based on the above reasons, the embodiment of the present invention firstly provides a photolithography process, including: providing a substrate, a film layer A and a film layer B are formed on one surface of the substrate, wherein the film layer B is located between the substrate and the between the film layers A; forming a photoresist layer on the surface of the film layer A; exposing the photoresist layer using a half-grayscale mask, wherein the half-grayscale mask includes a first region , the second area and the third area, and the light transmittance of the first area and the second area are opposite, and the third area is a semi-transparent area; the first area corresponding to the half-gray scale mask plate is removed by development Photoresist layer, and thin the photoresist layer corresponding to the third region of the half-grayscale mask plate; remove the film layer A corresponding to the first region of the half-grayscale mask plate; remove the half-grayscale mask plate The film layer B corresponding to the first region and the photoresist layer corresponding to the third region of the half-grayscale mask, and thinning the photoresist layer corresponding to the second region of the half-grayscale mask; remove the half-grayscale The film layer A corresponding to the third area of the mask; removing the photoresist layer corresponding to the second area of the half-gray scale mask to complete the photolithography.

Corresponding to the above photolithography process, the present invention also provides a method for manufacturing a thin film transistor, comprising: providing a substrate; forming silicon islands on the surface of the substrate; forming a transparent electrode layer and a gate on the surface of the substrate on which the silicon islands are formed. layer, wherein the transparent electrode layer is located between the substrate and the gate layer; a photoresist layer is formed on the surface of the gate layer; Exposure, wherein the half-grayscale mask includes a first region, a second region and a third region, and the light transmission properties of the first region and the second region are opposite, and the third region is semi-transparent region; development removes the photoresist layer corresponding to the first region of the half-grayscale mask plate, and thins the photoresist layer corresponding to the third region of the half-grayscale mask plate; removes the first region of the half-grayscale mask plate A grid layer corresponding to a region; removing the transparent electrode layer corresponding to the first region of the half-grayscale mask and the photoresist layer corresponding to the third region of the half-grayscale mask, and thinning the half-grayscale mask The photoresist layer corresponding to the second region of the plate; remove the gate layer corresponding to the third region of the half-grayscale mask; remove the photoresist layer corresponding to the second region of the half-grayscale mask to form a transparent electrode and the gate; form a passivation layer on the surface of the substrate with the transparent electrode and the gate, and form a via hole in the passivation layer; form a source and a drain on the surface of the substrate with the passivation layer electrode, the source electrode and the drain electrode are in contact with the surface of the silicon island and the transparent electrode through the passivation layer and the via hole in the insulating layer, and the fabrication of the thin film transistor is completed.

Corresponding to the manufacturing method of the above thin film transistor, the present invention also provides a thin film transistor, the gate and transparent electrode of the thin film transistor are completed by one photolithography, and the thin film transistor is formed by four photolithography.

The photolithography process provided by the present invention can meet the etching requirements for film layer A and film layer B only through one exposure through a half-gray-scale mask plate, and can reduce the process of photolithography process, thereby achieving simplified photolithography. The purpose of the process is to reduce the production cost. When the thin film transistor is manufactured by using this photolithography process, the manufacturing process of the thin film transistor can be simplified from six photolithography steps to four photolithography steps, which simplifies the manufacturing method of the thin film transistor and reduces the manufacturing cost of the thin film transistor.

In order to make the purpose, technical solutions and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are the Some, but not all, embodiments are invented. Based on the embodiments of the present invention, other embodiments obtained by persons of ordinary skill in the art without making creative efforts all belong to the protection scope of the present invention.

Secondly, the present invention is described in detail in combination with schematic diagrams. When describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic diagram is only an example, and it should not be limited here. The protection scope of the present invention. In addition, the three-dimensional space dimensions of length, width and depth should be included in actual production.

Embodiment one

This embodiment provides a photolithography process, as shown in Figures 7 to 9, comprising the following steps:

Step 1: As shown in FIG. 7 , a substrate 701 is provided, and a film layer A and a film layer B are formed on one surface of the substrate 701 , wherein the film layer B is located between the substrate 701 and the film layer A.

Step 2: As shown in FIG. 8, a photoresist layer 702 is formed on the surface of the film layer A. The photoresist layer 702 can be a positive photoresist or a negative photoresist layer, that is, In the present invention, the material of the photoresist layer 702 is not limited, and can be selected according to specific needs and process conditions.

Step 3: As shown in FIG. 9 , use a half-grayscale mask 703 to expose the photoresist layer 702, wherein the half-grayscale mask 703 includes a first region 7031, a second region 7032 and The third region 7033, and the light transmittance of the first region 7031 and the second region 7032 are opposite, and the third region 7033 is a semi-transparent region.

When the photoresist layer 702 is a positive photoresist layer, the first region 7031 of the half-gray-scale mask 703 is a light-transmitting region, and the second region 7032 is an opaque region; When the resist layer 702 is a negative photoresist layer, the first region 7031 of the half-gray scale mask 703 is an opaque region, and the second region 7032 is a transparent region. For ease of description, this embodiment takes the photoresist layer 702 as a positive photoresist layer as an example to describe the photolithography process provided in this embodiment.

It should be noted that the distribution of the first region, the second region and the third region of the half-grayscale mask 703 shown in FIG. 9 in this step is only an embodiment of the present invention. The distribution of the opaque area, transparent area and semi-transparent area of 703 can be designed according to the target etching pattern of the film layer A and film layer B, that is, the half-grayscale mask 703 of the present invention The specific shape is not limited.

After exposure, the photoresist layer corresponding to the opaque region 7032 of the half-grayscale mask 703 will not be affected by the exposure, and remains under the protection of the opaque region 7032 of the half-grayscale mask 703. The inherent properties of the photoresist layer; the photoresist layer corresponding to the light-transmitting region 7031 of the half-gray-scale mask 703 undergoes a photochemical reaction under the influence of exposure, so that the physical properties of the photoresist layer in this part, especially Solubility, affinity, etc. change significantly; the photoresist layer corresponding to the semi-transparent region 7033 of the half-gray scale mask 703, because the semi-transparent region 7033 can block part of the light irradiation, so the part of the In the photoresist layer, only the photoresist layer with a certain thickness close to the half-gray-scale mask 703 is affected by the exposure, and a photochemical reaction occurs, while the photoresist layer with a certain thickness close to the film layer A does not undergo photochemical reaction. .

Step 4: As shown in FIG. 10 , develop and remove the photoresist layer corresponding to the first region 7031 of the half-grayscale mask 703 , and thin the photoresist corresponding to the third region 7033 of the half-grayscale mask 703 layer.

During the exposure process in step 3, the part of the photoresist layer 702 corresponding to the light-transmitting region 7031 is completely deteriorated due to the effect of the half-gray-scale mask 703, and the part corresponding to the semi-transmitting region 7033 has only a certain thickness of the photoresist layer. The gum has deteriorated. Since development can remove the deteriorated photoresist layer, after development, while completely removing the photoresist layer corresponding to the light-transmitting region 7031, the photoresist layer corresponding to the semi-transparent region 7033 is thinned, as shown in Figure 10 The effect shown.

It should be emphasized that since the light transmission capacity of the semi-transparent region 7033 of the half-grayscale mask 703 can be adjusted as required, the photoresist layer corresponding to the semi-transparent region 7033 after development The thickness of can be controlled by adjusting the light transmittance of the semi-transparent region 7033 of the half-gray scale mask 703 .

Step 5: As shown in FIG. 11 , remove the film layer A corresponding to the first region 7031 of the half-grayscale mask 703 .

As shown in FIG. 10 , after the development, the part of the surface of the film layer A corresponding to the light-transmitting region 7031 of the photoresist layer 702 is completely removed, while the surface of the film layer A corresponding to other regions of the half-gray-scale mask 703 still exists. photoresist layer. At this time, under the protection of the remaining photoresist layer 702, the film layer A corresponding to the opaque region 7032 and the semi-transparent region 7033 of the half-grayscale mask 703 can be independently aligned with the half-grayscale mask 703 The film layer A corresponding to the light-transmitting region 7031 is etched, and only the film layer A corresponding to the light-transmitting region 7031 is removed, so that the shape of the film layer A is shown in FIG. 11 .

The etching method for removing the film layer A includes dry etching and wet etching, and wet etching is preferably used in this embodiment. If dry etching is used, the etching selectivity of the film layer A, the film layer B and the photoresist layer 702 needs to be considered.

Step 6: As shown in FIG. 12 , remove the film layer B corresponding to the first region 7031 of the half-grayscale mask 703 and the photoresist layer corresponding to the third region 7033 of the half-grayscale mask, and reduce the thickness by half The photoresist layer corresponding to the second region 7032 of the grayscale mask.

At this time, only the portion of the photoresist layer 702 corresponding to the opaque region 7032 of the half-grayscale mask still exists, and the photoresist layer corresponding to other regions of the half-grayscale mask 703 is completely removed. Moreover, the film layer B has reached the final shape requirement, and the etching of the film layer B is completed.

The etching methods used in this step include dry etching and wet etching, and dry etching is preferably used in this embodiment. Dry etching can etch different materials at the same time, so it is possible to etch the photoresist layer corresponding to the second region 7032 and the third region 7033 of the half-gray-scale mask while etching the film layer B. Carry out etching, as described in step 4, in combination with the etching rate of the photoresist layer and film layer B by dry etching, by adjusting the light transmission capacity of the semi-transparent region 7033 of the half-gray scale mask plate 703, ensure Dry etching removes the photoresist layer corresponding to the semi-transparent region 7033 while removing the film layer B corresponding to the transparent region 7031 of the half-grayscale mask 703 . Moreover, since the photoresist layer corresponding to the semi-transparent region 7033 is thinned in step 4, the thickness of the photoresist layer corresponding to the semi-transparent region 7033 is smaller than the thickness of the photoresist layer corresponding to the opaque region 7032 at this time, Therefore, after dry etching removes the film layer B corresponding to the translucent region 7031 and the photoresist layer corresponding to the semi-transmissive region 7033, the photoresist layer corresponding to the opaque region 7032 will not be completely removed, and can still be In the subsequent etching process, the film layer A and the film layer B corresponding to the opaque region 7032 are protected.

Step 7: As shown in FIG. 13 , remove the film layer A corresponding to the third region 7033 of the half-gray-scale mask 703, etch the film layer A into a prescribed shape, and complete the etching of the film layer A .

Step 8: As shown in FIG. 14 , remove the photoresist layer corresponding to the second region of the half-gray scale mask to complete photolithography.

The photolithography process provided in this embodiment only needs to be exposed once through a half-gray-scale mask to meet the etching requirements for film layer A and film layer B. After that, the film layer A and film layer B meet the specified etching pattern requirements. Under the premise that one exposure can correspond to multiple etchings, the etching of two film layers or circuit layers can be completed through one photolithography process, reducing the process of photolithography process, achieving the purpose of simplifying the photolithography process and reducing production costs .

Embodiment two

This embodiment provides a method for fabricating a thin film transistor, as shown in FIG. 15 , including the following steps:

Step 1501: providing a substrate, for a thin film transistor, the substrate is a transparent substrate, preferably, the substrate is a glass substrate;

Step 1502 : as shown in FIG. 16 , silicon islands 1602 are formed on the surface of the substrate 1601 .

According to the types of thin film transistors, the types of silicon islands 1602 currently include amorphous silicon islands, polycrystalline silicon islands, and single crystal silicon islands. High efficiency, low power consumption and other advantages, so low-temperature polysilicon thin film transistors are more and more valued by flat-panel display manufacturers, and their applications in smart phone displays are becoming more and more extensive. Therefore, in this embodiment, it is preferable to take a low-temperature polysilicon thin film transistor as an example to describe the method for fabricating the silicon island.

In one embodiment of the present invention, the method for forming polysilicon islands 1602 on the surface of the substrate 1601 includes: forming a polysilicon layer on the surface of the substrate; forming polysilicon islands by photolithography. In another embodiment of the present invention, the method for forming a silicon island 1602 on the surface of the substrate 1601 includes: forming an amorphous silicon layer on the surface of the substrate; forming an amorphous silicon island by photolithography; The crystalline silicon islands are used to crystallize the amorphous silicon islands into polycrystalline silicon islands.

It should be noted that the method of "laser processing the amorphous silicon island to crystallize the amorphous silicon island into a polysilicon island" is compatible with the manufacturing process of the amorphous silicon thin film transistor, that is, Using this method to manufacture polysilicon thin film transistors can directly apply existing equipment and methods for manufacturing amorphous silicon thin film transistors, without requiring equipment modification and reducing manufacturing costs.

Step 1503 : As shown in FIG. 17 , an insulating layer 1603 is formed on the surface of the substrate 1601 on which the silicon islands 1602 are formed, and the insulating layer 1603 covers the substrate and the silicon islands.

Step 1504: As shown in FIG. 18, a transparent electrode layer 1604 and a gate layer 1605 are formed on the surface of the insulating layer 1603, wherein the transparent electrode layer 1604 is located between the insulating layer 1603 and the gate layer 1605 between.

Step 1505: As shown in FIG. 19, a photoresist layer 1606 is formed on the surface of the gate layer 1605. The photoresist layer 1606 can be a positive photoresist layer or a negative photoresist layer, The present invention is not limited thereto.

Step 1506: As shown in FIG. 20 , use a half-grayscale mask 1607 to expose the photoresist layer 1606, wherein the half-grayscale mask 1607 includes a first region 1, a second region 2 and The third area 3, and the light transmission properties of the first area 1 and the second area 2 are opposite, and the third area 3 is a semi-transparent area.

When the photoresist layer 1606 is a positive photoresist layer, the first area 1 of the half-grayscale mask 1607 is a light-transmitting area, and the second area 2 is an opaque area; When the resist layer 1606 is a negative photoresist layer, the first region 1 of the shown half-grayscale mask 1607 is an opaque region, and the second region 2 is a light-transmitting region; the present invention uses the photoresist Layer 1606 is illustrated as an example of a positive tone photoresist layer, but the invention is still applicable to the case of a negative tone photoresist layer.

After the exposure is completed, photochemical reactions take place in all the photoresist layers corresponding to the light-transmitting area of the half-gray-scale mask 1607, while the photoresist layer corresponding to the semi-transparent area of the half-gray-scale mask 1607 receives less light than the light-transmitting area. Therefore, only the photoresist layer with a certain thickness close to the half-gray scale mask 1607 undergoes photochemical reaction.

Step 1507: As shown in FIG. 21 , develop and remove the photoresist layer corresponding to the first region 1 of the half-grayscale mask 1607, and thin the photoresist corresponding to the third region 3 of the half-grayscale mask 1607 layer;

Developing removes the photoresist that undergoes a photochemical reaction in step 1506, so as to remove the photoresist layer corresponding to the light-transmitting region 1 of the half-grayscale mask 1607 and reduce the semi-transmissiveness of the half-grayscale mask 1607 The photoresist layer corresponding to the area 3, meanwhile, the photoresist layer corresponding to the opaque area 2 of the half grayscale mask 1607 is reserved. Wherein, when thinning the photoresist layer corresponding to the semi-transparent region 3 of the half-grayscale mask 1607, the thickness of the thinned photoresist layer can be adjusted by half of the half-grayscale mask 1607. The light transmission ability of the light transmission area 3 is controlled.

Step 1508 : as shown in FIG. 22 , remove the gate layer 1605 corresponding to the light-transmitting region 1 of the half-gray scale mask 1607 .

Since only the photoresist layer is removed to protect the gate layer 1605 on the surface at this time, that is, the target etching material is single, and there is a photoresist layer in the part that does not need to be etched, so wet etching is preferably used to remove the corresponding half gray. The gate layer 1605 of the transparent region 1 of the step mask 1607 . If dry etching is used, the etching selectivity ratios of the gate layer 1605 , the transparent electrode layer 1604 and the photoresist layer 1606 need to be considered.

Step 1509: As shown in FIG. 23 , remove the transparent electrode layer 1604 corresponding to the transparent region 1 of the half-grayscale mask 1607 and the photoresist layer corresponding to the semi-transparent region 3 of the half-grayscale mask, and subtract The photoresist layer corresponding to the opaque region 2 of the thin half-grayscale mask 1607 .

The material of the transparent electrode layer 1604 is indium tin oxide, and the material of the photoresist layer is a photosensitive resin. Since the molecular activity of the indium tin oxide material and the photosensitive resin material are similar, plasma etching is preferably used in this step, so as to pass through once An etching process can accomplish this step. As described in step 1507, in combination with the etching rate of the photoresist layer and the transparent electrode layer by dry etching, the corresponding semi-transparent area is controlled by adjusting the light-transmitting ability of the semi-transparent area 3 of the half-gray scale mask 1607 3 to ensure that the dry etching removes the photoresist layer corresponding to the semi-transparent region 3 while etching the transparent electrode layer.

It should be noted that, in order to ensure that this step can be completed with one etching process, the thickness of the transparent electrode layer 1604 and the thickness of the photoresist layer 1606 can be adjusted according to the thickness of the transparent electrode layer 1604 and the thickness of the photoresist layer 1606 when using the half-gray-scale mask 1607 for exposure in step 1506. The light transmittance of the semi-transparent region 3 of the half-grayscale mask 1607 . Alternatively, during the formation of the photoresist layer 1606 in step 1505 , the thickness of the photoresist layer 1606 is adjusted according to the thickness of the transparent electrode layer 1604 and the light transmittance of the semi-transparent region 3 of the half-gray scale mask 1607 . Therefore, it is ensured that the implementation of plasma etching can just remove the photoresist layer corresponding to the semi-transparent region 3 while removing the transparent electrode layer corresponding to the transparent region 1 of the half-grayscale mask 1607 .

Step 1510 : as shown in FIG. 24 , remove the gate layer 1605 corresponding to the third region 3 of the half grayscale mask 1607 .

In this step, wet etching is preferably used to remove the gate layer 1605 corresponding to the semi-transparent region 3 of the half-grayscale mask 1607. If dry etching is used, it is necessary to consider the gate layer 1605, transparent electrode layer 1604 and photolithography. The etch selectivity of the adhesive layer 1606.

Step 1511 : as shown in FIG. 25 , remove the photoresist layer 1606 corresponding to the second region 2 of the half-gray scale mask 1607 to form a transparent electrode 1608 and a gate 1609 .

From step 1504 to step 1511, the transparent electrode 1608 and the gate 1609 of the thin film transistor are fabricated by a photolithography process. In this process, the photoresist layer is firstly exposed with a half-gray-scale mask to ensure that the photoresist layer in the semi-transparent area of the corresponding half-gray-scale mask still has a protective effect, and its thickness is smaller than the corresponding half-gray mask. The thickness of the photoresist layer in the opaque area of the grayscale mask. Then, after etching and removing the gate layer corresponding to the light-transmitting area of the half-grayscale mask, an etching process is used to simultaneously remove the transparent electrode layer corresponding to the light-transmitting area of the half-grayscale mask and the corresponding half-grayscale The photoresist layer in the semi-transparent area of the mask plate. Finally, the gate layer corresponding to the semi-transparent area of the half-gray-scale mask is removed by etching, and the film is stripped. That is to say, only one exposure is used in the whole process to realize the etching of the two structures of the gate electrode and the transparent electrode, which simplifies the manufacturing process of the thin film transistor.

It should be noted that, in the above manufacturing process, the gate can be a single-layer structure or a multi-layer structure; the transparent electrode can be used as a common electrode or a pixel electrode. The method provided in this embodiment does not limit the specific material and specific structure of the gate, transparent electrode and other parts of the thin film transistor.

Step 1512 : as shown in FIG. 26 , form a passivation layer 1610 on the surface of the transparent electrode 1608 , the gate 1609 and the insulating layer 1603 , and form a via hole 1611 in the passivation layer 1610 and the insulating layer 1603 .

The method of forming the via hole 1611 in the passivation layer 1610 and the insulating layer 1603 preferably adopts a photolithography process, first forming a photoresist layer on the surface of the flat passivation layer 1610; then performing exposure to remove the corresponding via hole 1611 The passivation layer and the insulating layer 1603 in the region, form the via hole 1611 in the passivation layer 1610 and the insulating layer 1603 , so that the source and drain electrodes in the subsequent steps can be in contact with the surface of the silicon island 1602 .

Step 1513: As shown in FIG. 27, a source electrode 1612 and a drain electrode 1613 are formed on the surface of the substrate 1601 where the passivation layer 1610 is formed, and the source electrode 1612 passes through the passivation layer 1610 and the passivation layer 1603. The hole 1611 is in contact with the surface of the silicon island 1602, and the drain 1613 is in contact with the silicon island 1602 and the transparent electrode 1608 through the passivation layer 1610 and the via hole 1611 in the insulating layer 1603, completing a thin film transistor production.

The method of forming the source electrode 1612 and the drain electrode 1613 is preferably formed by one photolithography process.

In summary, the manufacturing method of the thin film transistor provided by the present invention can be completed only by applying four photolithography processes, which simplifies the manufacturing process of the thin film transistor and reduces the manufacturing cost of the thin film transistor.

Embodiment three

This embodiment provides a thin film transistor, as shown in FIG. 27 , the thin film transistor is manufactured by using the manufacturing method described in the second embodiment. The gate and transparent electrode of this kind of thin film transistor are completed by one photolithography process, so the whole manufacturing process of this kind of thin film transistor only needs to use four photolithography processes, the manufacturing method is simple, and the cost is low.

The above-mentioned embodiments are only preferred embodiments of the present invention, and do not limit the present invention in any form.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with the art, without departing from the scope of the technical solution of the present invention, can use the methods and technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent of equivalent change Example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the technical solution of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims (10)

1. a photoetching process, is characterized in that, comprising:

There is provided a substrate, a surface of described substrate is formed with rete A and rete B, and wherein rete B is between described substrate and described rete A;

Photoresist layer is formed on described rete A surface;

Use half gray level mask plate to expose described photoresist layer, wherein, described half gray level mask plate comprises first area, second area and the 3rd region, and the light transmission of described first area and second area is contrary, and described 3rd region is semi-transparent region;

The photoresist layer that the first area of development removal half gray level mask plate is corresponding, and the photoresist layer that the 3rd region of thinning half gray level mask plate is corresponding;

Remove the rete A that the first area of half gray level mask plate is corresponding;

Remove the photoresist layer that the 3rd region of rete B corresponding to the first area of half gray level mask plate and half gray level mask plate is corresponding, and the photoresist layer that the second area of thinning half gray level mask plate is corresponding;

Remove the rete A that the 3rd region of half gray level mask plate is corresponding;

Remove the photoresist layer that the second area of half gray level mask plate is corresponding, complete photoetching.

2. a manufacture method for thin-film transistor, is characterized in that, adopts photoetching process as claimed in claim 1 to make grid and the transparency electrode of thin-film transistor, comprising:

One substrate is provided;

Silicon island is formed at described substrate surface;

The surface being formed with silicon island at described substrate forms insulating barrier, and described insulating barrier covers described substrate and described silicon island;

Form transparent electrode layer and grid layer on the surface of described insulating barrier, wherein, described transparent electrode layer is between described insulating barrier and described grid layer;

Photoresist layer is formed on described grid layer surface;

Use half gray level mask plate to expose described photoresist layer, wherein, described half gray level mask plate comprises first area, second area and the 3rd region, and the light transmission of described first area and second area is contrary, and described 3rd region is semi-transparent region;

The photoresist layer that the first area of development removal half gray level mask plate is corresponding, and the photoresist layer that the 3rd region of thinning half gray level mask plate is corresponding;

Remove the grid layer that the first area of half gray level mask plate is corresponding;

Remove the photoresist layer that the 3rd region of transparent electrode layer corresponding to the first area of half gray level mask plate and half gray level mask plate is corresponding, and the photoresist layer that the second area of thinning half gray level mask plate is corresponding;

Remove the grid layer that the 3rd region of half gray level mask plate is corresponding;

Remove the photoresist layer that the second area of half gray level mask plate is corresponding, form transparency electrode and grid;

Form passivation layer on the surface of described transparency electrode, grid and insulating barrier, and form via hole in described passivation layer and insulating barrier;

The surface being formed with passivation layer at described substrate forms source electrode and drain electrode, described source electrode is by the surface contact of the via hole in described passivation layer and insulating barrier and described silicon island, described drain electrode is contacted with described transparency electrode with described silicon island with the via hole in insulating barrier by described passivation layer, completes the making of thin-film transistor.

3. manufacture method according to claim 2, is characterized in that, when described photoresist layer is positive photoresist layer, the first area of described half gray level mask plate is transmission region, and second area is light tight region.

4. manufacture method according to claim 2, is characterized in that, when described photoresist layer is negative photo glue-line, the first area of described half gray level mask plate is light tight region, and second area is transmission region.

5. manufacture method according to claim 2, is characterized in that, the method removing grid layer corresponding to the first area of half gray level mask plate is wet etching.

6. manufacture method according to claim 2, it is characterized in that, remove the photoresist layer that the 3rd region of transparent electrode layer corresponding to the first area of half gray level mask plate and half gray level mask plate is corresponding, and the method for photoresist layer corresponding to the second area of thinning half gray level mask plate is dry etching.

7. manufacture method according to claim 2, is characterized in that, the method removing grid layer corresponding to the 3rd region of half gray level mask plate is wet etching.

8. manufacture method according to claim 2, is characterized in that, when described thin-film transistor is polycrystalline SiTFT, the method forming silicon island at described substrate surface comprises: form polysilicon layer at described substrate surface; Etch described polysilicon layer by photoetching process, form polysilicon island.

9. manufacture method according to claim 2, is characterized in that, when described thin-film transistor is polycrystalline SiTFT, the method forming silicon island at described substrate surface comprises: form amorphous silicon layer at described substrate surface; Etch described amorphous silicon layer by photoetching process, form amorphous silicon island; Amorphous silicon island described in laser treatment, makes described amorphous silicon island crystallization be polysilicon island.

10. the thin-film transistor that the manufacture method according to any one of claim 1-9 makes, it is characterized in that, the grid of described thin-film transistor and transparency electrode are completed by a photoetching, and described thin-film transistor is formed by four mask.