JP2006030320A - Gray tone mask and method of manufacturing gray tone mask - Google Patents

Abstract

As a gray-tone mask having a pattern in which a light-transmitting part, a light-shielding part, and a semi-transparent part are adjacent in this order in one direction, the transmittance distribution of the semi-transparent part is good and adjacent to the light-transmitting part Provided are a gray-tone mask having a good pattern cross-sectional shape of a light-shielding portion and a good pattern accuracy of a light-transmitting portion, and a method for manufacturing a gray-tone mask.
A gray-tone mask 10 having a pattern including a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion, wherein the light-transmitting portion, the light-shielding portion, and the semi-light-transmitting portion are arranged in one direction. The light-shielding part has a light-shielding film 13a that forms a light-shielding part, and a desired margin region on the light-shielding part side in the part adjacent to the light-transmitting part on the light-shielding film 13a. A semi-transparent film 12a formed in the excluded region is laminated.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a gray-tone mask suitably used for a thin film transistor substrate (hereinafter referred to as a TFT substrate) used for manufacturing a thin film transistor liquid crystal display.

TFT-LCDs are currently being commercialized rapidly due to the advantages of being thin and low in power consumption compared to CRTs (cathode ray tubes). A TFT-LCD includes a TFT substrate having a structure in which TFTs are arranged in pixels arranged in a matrix, and a color filter in which red, green, and blue pixel patterns are arranged corresponding to each pixel. It has a schematic structure superimposed under the intervention of. In TFT-LCD, the number of manufacturing processes is large, and the TFT substrate alone is manufactured using 5 to 6 photomasks.
Under such circumstances, a method of reducing the number of photolithography processes by a method of manufacturing a TFT substrate using four photomasks, that is, a method of using two kinds of film thickness of a photoresist pattern is proposed. .
For example, Patent Document 1 discloses a photoresist having a first thickness between a source electrode and a drain electrode (channel portion), a photoresist having a second thickness larger than the first thickness, and a first thickness. And a photoresist having a third thickness (including zero thickness) that is less than the thickness of the substrate.

Further, Patent Document 1 discloses two methods for forming a photoresist pattern having these two types of film thicknesses: (1) a gray tone having a light-transmitting portion, a light-blocking portion, and a semi-light-transmitting portion. A method using a mask and (2) a method of deforming a resist by reflowing the resist are disclosed.
As the gray tone mask described above, the semi-transparent portion is formed by a pattern smaller than the resolution of the exposure apparatus in which the mask is used, for example, a slit or lattice pattern, or a semi-transparent film is provided to There is a method of adjusting the amount of irradiation, and in the case of a semi-transparent film, the light-shielding chromium layer is not completely removed, leaving a certain thickness so that the amount of light entering through this portion is reduced. .
FIG. 8A shows an example in which a region corresponding to the source electrode and the drain electrode is a light shielding portion 204, and a region corresponding to a channel portion therebetween is a slit-shaped semi-translucent portion 203. b) is an example in which a region corresponding to the channel portion is formed of a semi-transparent film.
A gray-tone mask described in Patent Document 1 in which a region corresponding to a channel portion is a semi-translucent portion is referred to as a first example.

On the other hand, as another example of a TFT substrate manufacturing method, for example, Patent Document 2 discloses a TFT substrate manufacturing method using a combination of both a method using a gray-tone mask and a method of deforming a resist by reflow. ing.
Hereinafter, an example of the method described in Patent Document 2 will be described with reference to FIG.
As shown in FIG. 9A, a gate electrode 102 is formed on a glass substrate 101, a gate insulating film 103 is formed on the glass substrate 101 so as to cover the gate electrode 102, and on the gate insulating film 103, A silicon film 104, an n + silicon film 105, and a metal film 106 are sequentially deposited and laminated.
Next, a positive photoresist is applied on the metal film 106 to form a resist film 107. As shown in FIG. 9B, exposure light is applied to the resist film 107 through a gray-tone mask 201. Irradiate. FIG. 9 is a plan view of a gray tone mask. The light-shielding portion 204 is formed corresponding to a region adjacent to the channel portion that is a portion facing the source electrode and the drain electrode, and the remaining portion of the source electrode and the drain electrode is formed from the semi-transparent portion 203. A channel portion between the drain electrode and the drain electrode is formed by a light transmitting portion 205.

Next, when the positive photoresist after exposure is developed, the thick mask pattern 107a portion remains almost undissolved, the thin mask pattern 107b portion dissolves to some extent, and all other portions dissolve and disappear. As a result, as shown in FIG. 9C, a thick mask pattern 107a having a large film thickness and a thin mask pattern 107b having a small film thickness can be formed simultaneously.
Next, by performing etching using the thick mask pattern 107a and the thin mask pattern 107b as a mask, ohmic contact layers 105a and 105b, source electrodes 106a, and drain electrodes are formed on the silicon film 104 as shown in FIG. 9D. 106b is formed.
After the ohmic contact layers 105a and 105b are formed, the thick mask pattern 107a and the thin mask pattern 107b are reflowed by heating or the like. As a result, each mask pattern, which is an organic resin, spreads in the plane of the silicon film 104, and the thick mask pattern 107a and the thick mask pattern 107b are connected on the silicon film 104 between the ohmic contact layer 105a and the ohmic contact layer 105b. As shown in the plan views of FIGS. 9E and 11, a reflow mask pattern 108 is formed. FIG. 9E shows an xx cross section of FIG.

Next, the silicon layer 104 is etched away using the reflow mask pattern 108 as a mask, and the reflow mask pattern 108 is removed, so that the ohmic contact layers 105a and 105b, the source electrode 106a, and the drain electrode 106b are formed on the semiconductor island. A state is obtained (not shown). Thereafter, a passivation film is formed, contact holes are formed on the source electrode 106a and the drain electrode 106b, and a pixel electrode connected to the source electrode 106a and a terminal electrode connected to the drain electrode 106b are formed at the bottom of the contact holes. (Not shown).
The gray-tone mask described in Patent Document 2 in which the region excluding the facing portions of the source electrode and the drain electrode is a semi-transparent portion is referred to as a prior example 2.
JP 2000-165886 A Japanese Patent Laid-Open No. 2002-261078

As described in the previous example 2, the gray tone mask in which the region excluding the facing portion of the source electrode and the drain electrode is a semi-transparent portion has a large area occupied by the semi-transparent portion, and therefore the mask is used. If the semi-transmission part is formed with a fine pattern smaller than the resolution of the exposure apparatus, a uniform transmittance distribution in the semi-transmission part is deteriorated unless a high-precision fine pattern in a wide range is obtained. There is a problem.
Therefore, assuming that the semi-transparent portion is formed of a semi-transparent film, for example, a structure as shown in FIG. 12 can be considered.
A gray-tone mask 200 shown in FIG. 12A has a structure in which a light shielding portion is formed of a semi-transparent film and a light shielding film thereon (hereinafter referred to as a conventional structure example A). The gray-tone mask of the conventional structure example A can be manufactured by the method shown in FIG. 14 (hereinafter referred to as a conventional manufacturing example A).

That is, first, a mask blank 214 in which a semi-transparent film 212 and a light shielding film 213 are sequentially formed is prepared (see FIG. 14A).
Next, for example, a positive resist for electron beam or laser drawing is applied on the mask blank 214 and baked to form a resist film 215 (see FIG. 14B). Next, drawing is performed using an electron beam drawing machine or a laser drawing machine. After drawing, this is developed to form a resist pattern 215a on the mask blank (see FIG. 14C).
Next, the light shielding film 213 is etched using the formed resist pattern 215a as a mask, and then the semi-transparent film 212 is etched. The remaining resist pattern 215a is removed by ashing with oxygen or concentrated sulfuric acid (see FIG. 14D).
Next, the resist is applied again on the entire surface to form a resist film 216 (see FIG. 14E). Then, the second drawing is performed. After drawing, this is developed to form a resist pattern 216b for forming a light shielding film pattern (see FIG. 14F). Next, using the formed resist pattern 216b as a mask, the exposed light shielding film on the semi-transparent film is removed by etching. Thereby, the light shielding part is defined as a semi-translucent part, and the semi-transparent part and the light shielding part are formed (see FIG. 14G). The remaining resist pattern is removed using oxygen ashing or the like (see FIG. 14H).

In the above-described conventional manufacturing example A, in the etching of the light shielding film shown in FIG. 14G, the underlying semi-transparent film needs to be resistant to the etching of the light shielding film. Therefore, it is necessary to select a combination of materials having different etching characteristics for the light-shielding film and the semi-transparent film, and there is a problem that the range of material selection is limited.
Next, in the gray tone mask shown in FIG. 12B, the light shielding portion is formed of a light shielding film and a semi-transparent film thereon (hereinafter referred to as a conventional structure example B). The gray tone mask of the conventional structure example B can be manufactured by the method shown in FIG. 15 (hereinafter referred to as a conventional manufacture example B-1).

That is, first, a mask blank 224 having a light shielding film 213 formed on a transparent substrate 211 is prepared (see FIG. 15A).
On this mask blank 224, for example, a positive resist for laser or electron beam drawing is applied and baked to form a resist film 215. Next, drawing is performed using an electron beam drawing machine or a laser drawing machine. After the drawing, this is developed to form a first resist pattern 215a corresponding to the light shielding portion and the semi-transparent portion sandwiched between the light shielding portions on the mask blank (see FIG. 15B).
Next, using the formed first resist pattern 215a as a mask, the light shielding film 213 is wet or dry etched to form a pattern 213a corresponding to the light shielding portion (see FIG. 15C). The remaining resist pattern 215a is removed by ashing with oxygen or concentrated sulfuric acid (see FIG. 15D).

Next, a semi-transparent film 212 is formed on the entire surface (see FIG. 15E). Next, a resist film 216 for forming a semi-transparent film pattern is formed on the semi-transparent film 212 by applying a resist (see FIG. 15F). Then, the second drawing is performed. After drawing, this is developed to form at least a second resist pattern 216a corresponding to the semi-translucent portion (see FIG. 15G).
Next, using the formed resist pattern 216a as a mask, the semi-transparent film 212 and the light-shielding film 213a in the region to be a translucent part are continuously removed by wet or dry etching, and the semi-transparent film pattern 212a and the light-shielding film are removed. A pattern 213b is formed. Thereby, the semi-translucent part and the light-shielding part are defined as the translucent part, and the semi-translucent part, the light-shielding part and the translucent part are formed. Note that the remaining resist pattern is removed by oxygen ashing or the like (see FIG. 15H).

  According to the above-described conventional manufacturing example B-1, the semi-transparent portion has the semi-transparent film formed directly on the transparent substrate in which the region corresponding to the semi-transparent portion is exposed. When the semi-transparent portion is formed as in FIG. 1, it is not necessary to remove only the upper light-shielding film by etching and expose the lower semi-transparent film. For example, it can be formed of a film material having the same or similar etching characteristics such as a chromium / chromium compound, and the range of selection of the film material is widened. However, in the formation of the light-transmitting portion corresponding to the channel portion, when the light-shielding film and the semi-light-transmitting film are continuously etched, the total thickness of the light-shielding film and the semi-light-transmitting film is increased. It was difficult to form a pattern having a good cross-sectional shape. In particular, when a light-shielding film with an antireflection film is used as the light-shielding film, the etching rate differs between the lower layer part and the part of the antireflection layer. In such a case, it is possible to control the light shielding film material and the etching conditions so that the pattern cross-sectional shape when the light shielding film is etched in consideration of the surface antireflection layer. It was difficult to control with the laminated film. As a result, there is a problem that a pattern corresponding to a highly accurate channel portion cannot be formed, and the performance of the TFT is adversely affected when used in the manufacture of the TFT.

Furthermore, as a manufacturing method of the conventional structural example 2, there is the following method shown in FIG. 16 (hereinafter referred to as a conventional manufacturing example B-2).
That is, a mask blank 224 having a light shielding film 213 formed on a transparent substrate 211 is prepared (see FIG. 16A).
On the mask blank, for example, a positive resist for laser or electron beam drawing is applied and baked to form a resist film 215. Next, drawing is performed using an electron beam drawing machine or a laser drawing machine. After the drawing, this is developed to form a first resist pattern 215a corresponding to the light shielding portion on the mask blank (see FIG. 16B).
Next, using the formed first resist pattern 215a as a mask, the light shielding film 213 is wet or dry etched to form a pattern 213a corresponding to the light shielding portion (see FIG. 16C). The remaining resist pattern 215a is removed by ashing with oxygen or concentrated sulfuric acid (see FIG. 16D).

Next, a semi-transparent film 212 is formed on the entire surface (see FIG. 16E). Next, a resist film 216 for forming a semi-transparent film pattern is formed on the semi-transparent film 212 by applying a resist (see FIG. 16F). Then, the second drawing is performed. After drawing, this is developed to form a second resist pattern 216a corresponding to at least the semi-translucent portion (see FIG. 16G).
Next, using the formed resist pattern 216a as a mask, the semi-transparent film 212 in the region to be a translucent part is removed by wet or dry etching. Thereby, the semi-translucent part is defined as the translucent part, and the semi-translucent part and the translucent part are formed. Note that the remaining resist pattern 216a is removed by oxygen ashing or the like (see FIG. 16H).
According to the above-described conventional manufacturing example B-2, the semi-transparent film and the light-shielding film are continuously etched when forming the light transmitting portion corresponding to the channel portion as in the conventional manufacturing example B-1. Instead, since only the semi-transparent film is etched, the pattern can have a good cross-sectional shape.

However, in the conventional manufacturing example B-2, it is necessary to use a separate photolithography process for forming the semi-translucent portion and the light-shielding portion. As described above, when performing the second drawing, the second drawing is performed by performing alignment so that the pattern deviation does not occur with the first drawing. However, the alignment accuracy is limited and the alignment deviation is completely eliminated. It is difficult. Therefore, when the semi-transparent portion is a semi-transparent film, there is a problem that a good pattern may not be obtained due to misalignment of two-time drawing.
FIG. 13 is an enlarged view of a portion surrounded by a dotted line in FIG. FIG. 13A shows an example in which no misalignment occurs, and FIGS. 13B and 13C show the misalignment between the semi-translucent portion 203 and the light shielding portion 204 in FIG. 13A. This is an example. As in this example, when the translucent part is displaced from side to side, the width of the translucent part 205 corresponding to the channel part changes from the design value, and the TFT substrate characteristics change. It will occur. As described above, there is a problem in that a gray-tone mask that can form a channel portion that is particularly important in a TFT with high accuracy may not be obtained.

The present invention has been made in view of the above circumstances, and a pattern in which a light-transmitting portion, a light-shielding portion, and a semi-light-transmitting portion are adjacent to each other in this order in the same manner as in the gray-tone mask of the preceding example 2. Gray tone mask and gray tone having good transmissivity distribution of the semi-translucent part, good pattern cross-sectional shape of the light-shielding part adjacent to the translucent part, and good pattern accuracy of the translucent part An object is to provide a method for manufacturing a mask.
Furthermore, the present invention provides a gray-tone mask of the above-mentioned prior example 2, that is, a light-shielding portion formed in a portion corresponding to the source electrode and the drain electrode of the pattern corresponding to the source electrode and the drain electrode in the thin film transistor substrate, and the source electrode and the drain A resist pattern having a semi-translucent portion formed in a portion other than the light-shielding portion of the electrode and a translucent portion formed in another region including a portion corresponding to the channel portion, and formed at least by the light-shielding portion As a gray-tone mask used in the manufacturing process of a thin film transistor substrate having a process of deforming the film, the transmittance distribution of the semi-translucent part is good, and the pattern cross-sectional shape of the light-shielding part adjacent to the translucent part corresponding to the channel part is Gray tone mask and gray tone mask with good pattern accuracy corresponding to the channel part And to provide a method of manufacturing.

(Configuration 1) In a gray-tone mask having a pattern including a light shielding portion, a light transmitting portion, and a semi-light transmitting portion, the pattern has a light transmitting portion, a light shielding portion, and a semi-light transmitting portion adjacent to each other in this order. The light-shielding part is formed in a region excluding a light-shielding film that forms the light-shielding part and a desired margin region on the light-shielding part adjacent to the light-transmitting part on the light-shielding film. A gray-tone mask, wherein a semi-transparent film is laminated.
(Configuration 2) A light shielding portion formed in a portion corresponding to the source electrode and the drain electrode in a pattern corresponding to the source electrode and the drain electrode in the thin film transistor substrate, and a semi-transparent portion formed in a portion other than the light shielding portion of the source electrode and the drain electrode. A gray-tone mask used in a manufacturing process of a thin film transistor substrate having at least a light part and a light-transmitting part corresponding to a channel part adjacent to the light-shielding part, wherein the light-shielding part forms a light-shielding part. A gray tone characterized in that a film and a semi-transparent film formed in a region excluding a desired margin region on the light-shielding portion side in a portion adjacent to the light-transmitting portion on the light-shielding film are laminated mask.

(Configuration 3) A gray-tone mask having a pattern including a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion, and the light-transmitting portion, the light-shielding portion, and the semi-light-transmitting portion are adjacent to each other in this order. In a method of manufacturing a gray-tone mask having a pattern, a step of preparing a mask blank having at least a light shielding film formed on a transparent substrate, and a first drawing pattern on a first resist film for forming the light shielding film pattern A light shielding part pattern forming step including a step of drawing and developing to form a first resist pattern and etching the light shielding film using the first resist pattern as a mask, and then a transparent substrate on which the light shielding part is formed A step of forming a semi-transparent film thereon, and then drawing and developing a second drawing pattern on the second resist film formed on the semi-transparent film in order to form a semi-transparent film pattern Forming a second resist pattern, and using the second resist pattern as a mask, the step of etching the semi-transparent film includes a semi-transparent film pattern forming step, and the first drawing pattern includes: The second drawing pattern is a pattern corresponding to a light shielding part, and excludes a desired margin area on the light shielding part side in the semi-transparent part and at least a part of the light shielding part adjacent to the light shielding part. A method of manufacturing a gray-tone mask, wherein the pattern corresponds to a region.

(Configuration 4) A light-shielding portion formed in a portion corresponding to the source electrode and the drain electrode in a pattern corresponding to the source electrode and the drain electrode in the thin film transistor substrate, and a semi-transparent portion formed in a portion other than the light-shielding portion of the source electrode and the drain electrode. A gray-tone mask manufacturing method used in a manufacturing process of a thin film transistor substrate, having at least a light portion and a light-transmitting portion corresponding to a channel portion adjacent to the light-blocking portion, wherein at least a light-shielding film is formed on a transparent substrate A step of preparing a mask blank on which a first light-shielding film pattern is formed, a first drawing pattern is drawn and developed on a first resist film for forming a light-shielding film pattern, and the first resist pattern is formed. A light shielding part pattern forming step including a step of etching the light shielding film using the resist pattern as a mask, and then the light shielding part Forming a semi-transparent film on the formed transparent substrate, and then forming a second drawing pattern on the second resist film formed on the semi-transparent film in order to form the semi-transparent film pattern And a semi-transparent film pattern forming step including a step of forming a second resist pattern by drawing and developing, and etching the semi-transparent film using the second resist pattern as a mask. The pattern is a pattern corresponding to the light shielding portion, and the second drawing pattern is a desired pattern on the light shielding portion side in the semi-transparent portion and at least the light shielding portion of the light shielding portion and the adjacent portion of the light transmitting portion. A method for manufacturing a gray-tone mask, which is a pattern corresponding to an area excluding a margin area.

(Configuration 5) A gray-tone mask having a pattern including a light-shielding portion, a light-transmitting portion, and a semi-light-transmitting portion, and the light-transmitting portion, the light-shielding portion, and the semi-light-transmitting portion are adjacent to each other in this order. In a method for manufacturing a gray-tone mask having a pattern, a step of preparing a mask blank in which at least a semi-transparent film and a light shielding film are laminated on a transparent substrate, and a first resist film for forming a light shielding film pattern A light-shielding part pattern forming step including a step of drawing and developing a first drawing pattern to form a first resist pattern, and etching the light-shielding film using the first resist pattern as a mask, and a semi-transparent film pattern In order to form the second resist pattern formed on the translucent film, a second drawing pattern is drawn and developed to form a second resist pattern, and the second resist pattern is masked. A semi-transparent film pattern forming step including a step of etching the semi-transparent film, wherein the first drawing pattern is a pattern corresponding to the light shielding portion, and the second drawing pattern is the semi-transparent film A gray-tone mask manufacturing method comprising: a light-transmitting portion; and a pattern corresponding to a region excluding a desired margin region on the light-shielding portion side at least in the light-shielding portion and the adjacent portion of the light-transmitting portion. .

(Configuration 6) A light-shielding portion formed in a portion corresponding to the source electrode and the drain electrode in a pattern corresponding to the source electrode and the drain electrode in the thin film transistor substrate, and a semi-transparent portion formed in a portion other than the light-shielding portion of the source electrode and the drain electrode. A method for manufacturing a gray-tone mask used in a manufacturing process of a thin film transistor substrate, comprising at least a light portion and a light-transmitting portion corresponding to a channel portion adjacent to the light-shielding portion. A step of preparing a mask blank in which a light film and a light shielding film are laminated;
A step of drawing and developing a first drawing pattern on a first resist film for forming a light shielding film pattern to form a first resist pattern, and etching the light shielding film using the first resist pattern as a mask. A light-shielding portion pattern forming step, and a second resist pattern is drawn on the second resist film formed on the semi-transparent film to form the semi-transparent film pattern, and developed to form the second resist pattern. And a semi-transparent film pattern forming step including a step of etching the semi-transparent film using the second resist pattern as a mask, and the first drawing pattern is a pattern corresponding to the light shielding portion. And the second drawing pattern has a pattern corresponding to a region excluding a desired margin region on the light-shielding portion side in at least the light-shielding portion and the light-transmissive portion adjacent to the semi-light-transmissive portion and the light-shielding portion. Method for manufacturing a gray-tone mask, characterized in that it.

According to the gray tone mask of the present invention, the semi-transparent portion is formed of a semi-transparent film as a gray tone mask having a pattern in which the translucent portion, the light-shielding portion, and the semi-transparent portion are adjacent in this order in one direction. Since it is formed, the transmittance distribution of the semi-transparent portion can be obtained. In addition, since the light shielding portion adjacent to the light transmitting portion is formed by etching only the light shielding film, a pattern having a favorable cross-sectional shape of the light shielding portion adjacent to the light transmitting portion can be obtained. Furthermore, the light-shielding part is formed in a light-shielding film that forms the light-shielding part, and a semi-light-transmitting film formed on the light-shielding film in a region excluding a desired margin region on the light-shielding part side adjacent to the light-transmitting part Are stacked, so that a gray-tone mask with good pattern accuracy of the translucent portion can be obtained.
Furthermore, according to the gray-tone mask of the present invention, the light-shielding portion formed in the opposing portion of the source electrode and the drain electrode in a pattern corresponding to the source electrode and the drain electrode in the thin film transistor substrate, and the light-shielding portion other than the light-shielding portion of the source electrode and the drain electrode As a gray-tone mask used in a manufacturing process of a thin film transistor substrate having a semi-transparent portion formed in a portion of the thin film and a translucent portion formed in another region including a portion corresponding to the channel portion, Since the portion is formed of a semi-transparent film, the transmittance distribution of the semi-transparent portion can be obtained. Further, since the light shielding portion adjacent to the light transmitting portion is formed by etching only the light shielding film, a pattern having a favorable cross-sectional shape of the light shielding portion adjacent to the channel portion can be obtained. Furthermore, the light-shielding part is formed in a light-shielding film that forms the light-shielding part, and a semi-light-transmitting film formed on the light-shielding film in a region excluding a desired margin region on the light-shielding part side adjacent to the light-transmitting part Are stacked, so that a gray-tone mask with good pattern accuracy of the light transmitting portion corresponding to the channel portion can be obtained.

Furthermore, according to the method for manufacturing a gray-tone mask of the present invention, the semi-transparent portion is formed as a gray-tone mask having a pattern in which the translucent portion, the light-shielding portion, and the semi-transparent portion are adjacent in this order in one direction. Since it is formed of a semi-transparent film, the transmittance distribution of the semi-transparent part can be obtained. In addition, since the light shielding portion adjacent to the light transmitting portion is formed by etching only the light shielding film, a pattern having a favorable cross-sectional shape of the light shielding portion adjacent to the light transmitting portion can be obtained. Further, the second drawing data for forming the semi-transparent film pattern is obtained by removing the semi-transparent part and a desired margin area on the light-shielding part side at least in the light-shielding part and the adjacent part of the light-shielding part. By making the pattern corresponding to the above, it is possible to manufacture a gray-tone mask with good pattern accuracy of the light transmitting part.
Further, according to the gray-tone mask manufacturing method, the light-shielding portion formed in the opposing portion of the source electrode and the drain electrode in a pattern corresponding to the source electrode and the drain electrode in the thin film transistor substrate, and the light-shielding portion other than the light-shielding portion of the source electrode and the drain electrode As a method for manufacturing a gray-tone mask used in a manufacturing process of a thin film transistor substrate having a semi-transparent portion formed in the portion of, and a transparent portion formed in another region including a portion corresponding to the channel portion, Since the semi-transparent portion is formed of a semi-transparent film, the transmittance distribution of the semi-transparent portion can be obtained. Further, since the light shielding portion adjacent to the light transmitting portion is formed by etching only the light shielding film, a pattern having a favorable cross-sectional shape of the light shielding portion adjacent to the channel portion can be obtained. Further, the second drawing data for forming the semi-transparent film pattern is obtained by removing the semi-transparent part and a desired margin area on the light-shielding part side at least in the light-shielding part and the adjacent part of the light-shielding part. By using the pattern corresponding to the above, it is possible to manufacture a gray-tone mask with good channel portion pattern accuracy.

Hereinafter, the present invention will be described in detail by embodiments.
FIG. 1 is a cross-sectional view showing a pattern near a source electrode and a drain electrode on a TFT substrate of a gray-tone mask according to Embodiment 1 of the present invention, and FIG. 2A is surrounded by a dotted line in FIG. FIG.
As shown in FIGS. 1 and 2, in the present embodiment, a light shielding film pattern 13a is formed on a transparent substrate 11 made of quartz or the like in a region facing a source electrode and a drain electrode and adjacent to a channel portion. A semi-transparent film pattern 12a is formed in the region on the light shielding film and the source and drain electrode portions excluding the margin region 17 on the electrode side in the portion adjacent to the source and drain electrodes and the channel portion. That is, the portion laminated with the semi-transparent film pattern 12a formed in the region on the light-shielding film excluding the light-shielding film pattern 13a and the margin region 17 is the light-shielding portion, and the region where the semi-transparent film other than the light-shielding portion is formed. The translucent portion is a region where neither the semi-transparent portion nor the semi-transparent film 12a or the light-shielding film 13a is formed.

Next, a method for manufacturing the gray tone mask will be described with reference to FIG.
In the present embodiment, first, as shown in FIG. 3A, a light shielding film 13 made of, for example, a Cr-based material is formed on a large transparent substrate 11 made of quartz or the like and having a main surface size of 450 mm × 550 mm. The mask blank 14 is used.
On the mask blank, for example, a positive resist for laser or electron beam drawing is applied and baked to form a first resist film 15 for forming a light shielding film pattern (see FIG. 3B). ). Next, drawing is performed using an electron beam drawing machine or a laser drawing machine. The drawing data (first drawing data) is pattern data corresponding to the light-shielding film pattern 13a corresponding to a region adjacent to the channel portion, which is a portion facing the source electrode and the drain electrode, shown in FIG. After the drawing, this is developed to form a first resist pattern 15a corresponding to the light shielding portion on the mask blank.

  In the TFT substrate manufacturing process using the gray tone mask of the present embodiment, the source electrode and the drain electrode are formed on the gate electrode at a predetermined interval as in the gray tone mask of the second example. Since the source and drain electrodes need to be aligned, marks related to the alignment with the gate electrode (positioning marks for exposure, marks for checking position accuracy, etc.) must be provided on the mask. In that case, since it is important that the channel portion sandwiched between the source electrode and the drain electrode is accurately aligned with the gate electrode, the thin film pattern formed closest to the channel portion of the source electrode and the drain electrode It is preferable to provide a correlated mark outside the pattern region of the photomask. In the present invention, the thin film pattern formed on the most channel side of the source electrode and the drain electrode is a light shielding film pattern. Therefore, in the present embodiment, in the above process, the drawing data for forming the light shielding film pattern (first drawing data) includes the mark related to the alignment with the gate electrode, and the formation of the light shielding film pattern. A mark is also formed in the same manner, and a mark pattern formed of a light shielding film can be formed in the subsequent steps in the same manner as the light shielding film pattern.

Next, using the formed first resist pattern 15a as a mask, the light shielding film 13 is wet or dry etched to form a pattern 13a corresponding to the light shielding portion (see FIG. 3C). When the light shielding film 13 is made of a Cr-based material, for example, an etchant diluted with a mixture of ceric ammonium nitrate and peroxygen salt can be used for wet etching, and Cl ₂ + O ₂ can be used for dry etching. A dry etching gas containing a chlorine-based gas such as can be used. The remaining resist pattern 15a is removed using ashing with oxygen or concentrated sulfuric acid (see FIG. 3D).
Next, a semi-transparent film 12 is formed on the entire surface (see FIG. 3E). Next, a resist is applied on the semi-transparent film 12 to form a second resist film 16 for forming a semi-transparent film pattern (see FIG. 3F). Then, the second drawing is performed. The drawing data (second drawing data) at this time is pattern data corresponding to the source electrode and the drain electrode excluding the margin region 17 on the electrode side in the adjacent portion of the source and drain electrodes and the channel portion. After drawing, this is developed to form at least a second resist pattern 16a corresponding to the semi-translucent portion (see FIG. 3G). Note that this margin region has a width from the channel portion side that is larger than an assumed misalignment in consideration of the alignment accuracy of two-time drawing. However, if the margin area is large, there is a possibility that high light reflection by the exposed light-shielding film may cause a problem when the mask is used. Therefore, in the case of this embodiment, it is preferable to set in the range of 0.1 to 1 μm.

Next, using the formed second resist pattern 16a as a mask, the semi-transparent film 12 in a region to be a translucent part is removed by wet or dry etching. Thereby, the semi-translucent part is defined as the translucent part, and the semi-translucent part and the translucent part are formed. The remaining resist pattern is removed using oxygen ashing or the like (see FIG. 3H).
As described above, the gray tone mask 10 of the present embodiment shown in FIG. 1 is completed.
2 (b) and 2 (c) show an alignment misalignment between the drawing by the first drawing pattern and the drawing by the second drawing pattern in the above method with respect to the ideal structure of FIG. 2 (a). FIG. 2B shows an example in which the second drawing pattern is on the right side of the drawing with respect to the first drawing pattern, and FIG. 2C shows the first drawing pattern with respect to the first drawing pattern. This is an example in which the drawing pattern 2 is shifted to the left side in the drawing. As shown in these drawings, in the gray-tone mask in the present embodiment, the second drawing data includes the source electrode, the drain electrode, and the source electrode excluding the electrode-side margin region 17 in the adjacent portion of the channel portion. Since this is pattern data corresponding to the drain electrode, and the margin region is provided on the channel portion side to form the semi-transparent film pattern 12a, the pattern dimensional accuracy corresponding to the channel portion can be improved even if misalignment occurs. There is no worsening.
Therefore, according to this embodiment, a pattern important for TFT characteristics can be formed with high accuracy, and a high-quality gray-tone mask can be provided.

  The material of the light shielding film 13 is preferably a thin film that provides high light shielding properties, and examples thereof include Cr, Si, W, and Al. In addition, it is preferable that the light shielding film 13 has an antireflection layer made of, for example, the metal oxide on the front surface or the front surface, so that the drawing accuracy is improved when performing laser drawing. Further, the light-shielding film 13 may be a multilayer film or a composition gradient film whose composition is changed in order to sequentially adjust the etching rate so that the cross-sectional shape by etching becomes favorable. Further, the material of the semi-transparent film 12 is preferably a thin film that can obtain a semi-transmissivity with a transmissivity of about 50% when the transmissivity of the translucent part is 100%. For example, a Cr compound (Cr Oxide, nitride, oxynitride, fluoride, etc.), MoSi, Si, W, Al and the like. Si, W, Al, and the like are materials that can provide high light-shielding properties or semi-light-transmitting properties depending on the film thickness. Further, since the light-shielding portion of the mask to be formed is a laminate of the semi-transparent film 12 and the light-shield film 13, the light-shielding property can be obtained when the light-shielding film alone is combined with the semi-transparent film even if the light shielding property is insufficient. It ’s fine. Here, the transmittance is the transmittance with respect to the wavelength of the exposure light of, for example, a large LCD exposure machine using a gray tone mask. The transmissivity of the translucent film need not be limited to about 50%. How much the translucency of the semi-translucent portion is set is a design problem.

The material of the light shielding film 13 and the semi-transparent film 12 may have the same or similar etching characteristics, but side etching of the light shielding film when the semi-transparent film is etched and a margin region is formed. In consideration of the shaving of the underlying light shielding film, it is preferable that the light shielding film be made of a material having resistance when the semi-transparent film is etched. Further, an etching stopper layer may be provided before the semi-transparent film is formed in order to prevent the above-described side etching and undercutting. For example, SiO ₂ or SOG (Spin on Glass) can be used as the etching stopper layer. These materials have good permeability, and even if they are interposed in the semi-translucent portion, their transmission characteristics are not impaired, and it is possible to leave them out.

Next, a second embodiment of the present invention will be described. The second embodiment is an example in which the present invention is applied to a method for manufacturing a gray-tone mask having the structure shown in FIG.
As shown in FIG. 4A, the mask blank 24 used in this embodiment is made of a light shielding film material and etching selectivity on a large transparent substrate 11 made of quartz or the like and having a main surface size of 450 mm × 550 mm. A semi-transparent film 12 made of a material having a light-shielding film and a light-shielding film 13 made of, for example, a chromium-based material are sequentially formed.
The mask blank 24 can be obtained by sequentially forming the semi-transparent film 12 and the light-shielding film 13 on the transparent substrate 11, and the film forming method is vapor deposition, sputtering, CVD (chemical vapor deposition). A method suitable for the film type, such as a method, may be appropriately selected. The film thickness is not particularly limited, but the film thickness may be optimized so as to obtain good light-shielding property or semi-light-transmitting property.

Next, for example, a positive resist for electron beam or laser drawing is applied on the mask blank 24 and baked to form a first resist film 15 for forming a light shielding film pattern (FIG. 4 ( b)). Next, drawing is performed using an electron beam drawing machine or a laser drawing machine. The drawing data (first drawing data) is pattern data corresponding to the light-shielding film pattern 13a corresponding to a region adjacent to the channel portion, which is a portion facing the source electrode and the drain electrode, shown in FIG. After the drawing, this is developed to form a first resist pattern 15a corresponding to the light shielding portion on the mask blank (see FIG. 4B).
In addition, regarding the formation of the mark related to the alignment with the gate electrode, the mark related to the alignment with the gate electrode is included in the drawing data (first drawing data) for forming the light shielding film pattern in the above process. The mark is also formed at the same time as the formation of the semi-transparent film pattern. In the subsequent steps, the mark pattern formed by the semi-transparent film can be formed in the same manner as the semi-transparent film pattern.

Next, using the formed resist pattern 15a as a mask, the light shielding film 13 is dry-etched to form a light shielding film pattern 13a corresponding to the light shielding portion (see FIG. 4C). When the light shielding film 13 is made of a Cr-based material, dry etching using chlorine gas can be used. Except for the region corresponding to the light shielding portion, the underlying semi-transparent film 12 is exposed by etching the light shielding film 13. The remaining resist pattern 15a is removed using ashing with oxygen or concentrated sulfuric acid (see FIG. 4D).
Next, the resist is applied again on the entire surface to form a second resist film 16 (see FIG. 4E). Then, the second drawing is performed. The drawing data (second drawing data) at this time is pattern data corresponding to the source and drain electrodes excluding the margin region 17 on the electrode side in the adjacent portion of the source and drain electrodes and the channel portion shown in FIG. is there. After drawing, this is developed to form a resist pattern 16a for forming a translucent film pattern (see FIG. 4F). The width of this margin area is the same as that in the first embodiment.

Next, using the formed resist pattern 16a and light-shielding film pattern 13a as a mask, the semi-transparent film 12 in a region to be a translucent part is removed by dry etching. In this case, since the light shielding film pattern 13a is resistant to the etching of the semi-transparent film 12, the semi-transparent film 12 is etched along the light shielding film pattern 13a. Thereby, the semi-translucent part is defined as the translucent part, and the semi-translucent part and the translucent part are formed (see FIG. 4G). The remaining resist pattern is removed using oxygen ashing or the like (see FIG. 4H).
As described above, the gray tone mask of the present embodiment is completed.

  FIG. 5 is an enlarged view of a portion surrounded by the dotted lines in (f) and (g) of FIG. 4. With respect to the ideal structure of FIG. FIG. 5B is an example assuming a case in which the second drawing pattern is misaligned. FIG. 5B shows the second drawing pattern on the right side of the drawing with respect to the first drawing pattern. 5 (c) is an example in which the second drawing pattern is shifted to the left in the drawing with respect to the first drawing pattern. As shown in these drawings, in the gray-tone mask in the present embodiment, the second drawing data includes the source and drain electrodes and the source electrode excluding the electrode-side margin region 17 in the adjacent portion of the channel portion. Since this pattern data corresponds to the drain electrode, and the second resist pattern 16a is formed by providing a margin region on the channel portion side, the pattern dimension accuracy corresponding to the channel portion can be improved even if misalignment occurs. There is no worsening.

On the other hand, FIG. 6 is a diagram showing a case where, for comparison, in the above method, pattern data corresponding to the source electrode and the drain electrode is provided in the second drawing pattern without providing a margin region. In other words, in the above method, the drawing with the first drawing pattern and the drawing with the second drawing pattern are assumed to be misaligned with respect to the ideal structure of FIG. In FIG. 6B, the second drawing pattern is shifted to the right side in the drawing with respect to the first drawing pattern, and in FIG. 6C, the second drawing pattern is shifted to the left side in the drawing with respect to the first drawing pattern. It is an example.
As shown in these drawings, in an example in which no margin region is provided, the pattern accuracy corresponding to the channel portion is deteriorated due to the occurrence of misalignment.
As described above, according to the present embodiment, a pattern important in terms of TFT characteristics is formed with high accuracy, so that a high-quality gray-tone mask can be provided.

  In the second embodiment, the same material as that of the first embodiment can be used as the material of the light shielding film 13 and the semi-transparent film 12. However, regarding the combination of the materials of the light-shielding film 13 and the semi-transparent film 12, the etching characteristics of the films differ from each other, and the other film needs to have resistance in the etching environment of one film. For example, when the light-shielding film 13 is made of Cr and the semi-transparent film 12 is made of MoSi, the Cr light-shielding film is dry-etched using a chlorine-based gas or an etching solution diluted by mixing ceric ammonium nitrate and a peroxygen salt. When wet etching is used, a high etching selectivity can be obtained with the underlying MoSi semi-transparent film, so that only the Cr light-shielding film can be removed by etching with little damage to the MoSi semi-transparent film. Is possible. Furthermore, it is desirable that the light shielding film 13 and the semi-transparent film 12 have good adhesion when formed on a substrate.

The material of the light shielding film 13 and the semi-transparent film 12 may have the same or similar etching characteristics, and a mask blank in which an etching stopper layer is provided between the semi-transparent film 13 and the light shielding film 12 may be used. it can. For example, SiO ₂ or SOG (Spin on Glass) can be used as the etching stopper layer. These materials have good permeability, and even if they are interposed in the semi-translucent portion, their transmission characteristics are not impaired, and it is possible to leave them out.
In the above-described embodiment, the example in which the margin region is provided only on the channel portion side of the light shielding portion has been described. However, as shown in FIG. 7, the margin is also applied to other portions where the light shielding portion and the light transmitting portion are adjacent to each other. Region 18 may be provided. By providing the margin region 18, it is possible to prevent the translucent film from protruding from the light shielding portion even when an alignment shift occurs in the Y direction.
In the above-described embodiment, the gray-tone mask for manufacturing the TFT substrate of the preceding example 2 is exemplified. However, in the present invention, the light-transmitting portion, the light-shielding portion, and the semi-light-transmitting portion are adjacent in this order in one direction. The present invention can be applied to a gray tone mask having a pattern.

FIG. 3 is a cross-sectional view of the gray tone mask according to the first embodiment. 2 is a partially enlarged view of a gray tone mask according to Embodiment 1. FIG. 6 is a manufacturing process diagram of the gray-tone mask according to Embodiment 1. FIG. 6 is a manufacturing process diagram of a gray-tone mask according to Embodiment 2. FIG. It is the elements on larger scale of the gray tone mask which concerns on Embodiment 2. FIG. It is the elements on larger scale of the gray tone mask which concerns on a comparative example. It is a top view of the gray tone mask which concerns on other embodiment. It is a top view of the conventional gray tone mask. It is a manufacturing process figure of the conventional TFT substrate. It is a top view of the conventional gray tone mask. It is a top view of the TFT substrate in the conventional manufacturing stage. It is sectional drawing of the conventional gray tone mask. It is the elements on larger scale of the conventional gray tone mask. It is a manufacturing process figure of the conventional gray tone mask. It is a manufacturing process figure of the conventional gray tone mask. It is a manufacturing process figure of the conventional gray tone mask.

Brief description of symbols

DESCRIPTION OF SYMBOLS 10 Gray tone mask 11 Transparent substrate 12 Semi-transparent film 12a Semi-transparent film pattern 13 Light-shielding film 13a Light-shielding film pattern 14 Mask blank 15, 16 Resist film

Claims (6)

In a gray-tone mask having a pattern composed of a light-shielding part, a light-transmitting part, and a semi-light-transmitting part,
The pattern has a pattern in which a light-transmitting portion, a light-blocking portion, and a semi-light-transmitting portion are adjacent in this order in one direction, and the light-blocking portion includes a light-blocking film that forms the light-blocking portion, and the light-blocking film A gray-tone mask, wherein a semi-transparent film formed in a region excluding a desired margin region on a light shielding portion side adjacent to the light transmitting portion is laminated. A light-shielding portion formed in a portion corresponding to the source electrode and the drain electrode in a pattern corresponding to the source electrode and the drain electrode in the thin film transistor substrate; a semi-translucent portion formed in a portion other than the light-shielding portion of the source electrode and the drain electrode; A gray-tone mask used in a manufacturing process of a thin film transistor substrate, having at least a light-transmitting portion corresponding to a channel portion adjacent to the light shielding portion,
The light-shielding portion includes a light-shielding film that forms the light-shielding portion and a semi-transparent film formed on the light-shielding film in a region excluding a desired margin region on the light-shielding portion side adjacent to the light-transmissive portion. A gray-tone mask characterized by being laminated. A gray-tone mask having a pattern composed of a light-shielding part, a light-transmitting part, and a semi-light-transmitting part, and having a pattern in which the light-transmitting part, the light-shielding part, and the semi-light-transmitting part are adjacent in this order in one direction In the tone mask manufacturing method,
Preparing a mask blank having at least a light shielding film formed on a transparent substrate; and
A step of drawing and developing a first drawing pattern on a first resist film for forming a light shielding film pattern to form a first resist pattern, and etching the light shielding film using the first resist pattern as a mask. Including a light shielding part pattern forming step,
Next, a step of forming a semi-transparent film on the transparent substrate on which the light shielding portion is formed,
Next, a second drawing pattern is drawn and developed on the second resist film formed on the semi-transparent film in order to form a semi-transparent film pattern, thereby forming the second resist pattern. A semi-transparent film pattern forming step including a step of etching the semi-transparent film using the resist pattern as a mask,
The first drawing pattern is a pattern corresponding to the light shielding portion, and the second drawing pattern is light shielding in the semi-translucent portion and at least the light shielding portion of the light shielding portion and the adjacent portion of the light transmitting portion. A method of manufacturing a gray-tone mask, wherein the pattern corresponds to a region excluding a desired margin region on the side. A light-shielding portion formed in a portion corresponding to the source electrode and the drain electrode in a pattern corresponding to the source electrode and the drain electrode in the thin film transistor substrate; a semi-translucent portion formed in a portion other than the light-shielding portion of the source electrode and the drain electrode; A gray-tone mask manufacturing method used in a manufacturing process of a thin film transistor substrate, having at least a light-transmitting portion corresponding to a channel portion adjacent to the light shielding portion,
Preparing a mask blank having at least a light shielding film formed on a transparent substrate; and
A step of drawing and developing a first drawing pattern on a first resist film for forming a light shielding film pattern to form a first resist pattern, and etching the light shielding film using the first resist pattern as a mask. Including a light shielding part pattern forming step,
Next, a step of forming a semi-transparent film on the transparent substrate on which the light shielding portion is formed,
Next, a second drawing pattern is drawn and developed on the second resist film formed on the semi-transparent film in order to form a semi-transparent film pattern, thereby forming the second resist pattern. A semi-transparent film pattern forming step including a step of etching the semi-transparent film using the resist pattern as a mask,
The first drawing pattern is a pattern corresponding to the light shielding portion, and the second drawing pattern is light shielding in the semi-translucent portion and at least the light shielding portion of the light shielding portion and the adjacent portion of the light transmitting portion. A method of manufacturing a gray-tone mask, wherein the pattern corresponds to a region excluding a desired margin region on the side. A gray-tone mask having a pattern composed of a light-shielding part, a light-transmitting part, and a semi-light-transmitting part, and having a pattern in which the light-transmitting part, the light-shielding part, and the semi-light-transmitting part are adjacent in this order in one direction In the tone mask manufacturing method,
Preparing a mask blank in which at least a semi-transparent film and a light-shielding film are laminated on a transparent substrate;
A step of drawing and developing a first drawing pattern on a first resist film for forming a light shielding film pattern to form a first resist pattern, and etching the light shielding film using the first resist pattern as a mask. Including a light shielding part pattern forming step,
In order to form the semi-transparent film pattern, a second resist pattern is drawn on the second resist film formed on the semi-transparent film and developed to form a second resist pattern. A semi-transparent film pattern forming step including a step of etching the semi-transparent film using the pattern as a mask,
The first drawing pattern is a pattern corresponding to the light shielding portion, and the second drawing pattern is light shielding in the semi-translucent portion and at least the light shielding portion of the light shielding portion and the adjacent portion of the light transmitting portion. A method of manufacturing a gray-tone mask, wherein the pattern corresponds to a region excluding a desired margin region on the side. A light-shielding portion formed in a portion corresponding to the source electrode and the drain electrode in a pattern corresponding to the source electrode and the drain electrode in the thin film transistor substrate; a semi-translucent portion formed in a portion other than the light-shielding portion of the source electrode and the drain electrode; A gray-tone mask manufacturing method used in a manufacturing process of a thin film transistor substrate, having at least a light-transmitting portion corresponding to a channel portion adjacent to the light shielding portion,
Preparing a mask blank in which at least a semi-transparent film and a light-shielding film are laminated on a transparent substrate;
A step of drawing and developing a first drawing pattern on a first resist film for forming a light shielding film pattern to form a first resist pattern, and etching the light shielding film using the first resist pattern as a mask. Including a light shielding part pattern forming step,
In order to form the semi-transparent film pattern, a second resist pattern is drawn on the second resist film formed on the semi-transparent film and developed to form a second resist pattern. A semi-transparent film pattern forming step including a step of etching the semi-transparent film using the pattern as a mask,
The first drawing pattern is a pattern corresponding to the light shielding portion, and the second drawing pattern is light shielding in the semi-translucent portion and at least the light shielding portion of the light shielding portion and the adjacent portion of the light transmitting portion. A method of manufacturing a gray-tone mask, wherein the pattern corresponds to a region excluding a desired margin region on the side.

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