JP2007256922A - Pattern forming method, method of manufacturing gray tone mask, and pattern transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the deposition of contamination generated from a resist on a substrate or a film. <P>SOLUTION: In a method of manufacturing a gray tone mask 10 having a light shielding part 13, translucent part 14, and gray tone part 15 for reducing a transmission amount of exposure light, the method includes: a step of preparing a mask blank 20 obtained by sequentially forming a semi-translucent film 17 containing molybdenum and silicon, and a light shielding film 18 consisting primarily of chromium, on a translucent substrate 16; a step of forming a first resist pattern 21 on the light shielding film; a step of forming a light shielding film pattern 22 by etching the light shielding film using an etchant for chromium while using the first resist pattern as a mask; a step of peeling a remaining first resist pattern 21, subsequently; a step of etching the semi-translucent film 17 using the etchant for MoSi by using the light shielding film pattern as the mask; and a step of forming a gray tone part and light shielding part by etching a part other than a desired portion of the light shielding film pattern 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pattern formation method for patterning a thin film containing metal and silicon by etching, a thin film transistor (hereinafter referred to as TFT) of a liquid crystal display device (hereinafter referred to as LCD), and the like. The present invention relates to a gray tone mask manufacturing method that is preferably used, and a pattern transfer method that includes a step of exposing exposure light onto a transfer target.

  LCD TFTs are currently being rapidly commercialized due to the advantages of being thinner and lower in power consumption than CRTs (cathode ray tubes). The TFT of the LCD includes a TFT substrate having a structure in which a TFT is arranged in each pixel 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 intervening phase. This LCD TFT has a large number of manufacturing steps, and the TFT substrate alone is manufactured using 5 to 6 photomasks.

  Under such circumstances, a method of manufacturing a TFT substrate using four photomasks has been proposed. In this method, the number of masks to be used is reduced by using a photomask (hereinafter referred to as a gray tone mask) having a light shielding portion, a light transmitting portion, and a semi-light transmitting portion (gray tone portion). 3 and 4 show an example of a manufacturing process of a TFT substrate using a gray tone mask.

  A metal film for a gate electrode is formed on the glass substrate 1, and the gate electrode 2 is formed by a photolithography process using a photomask. Thereafter, a gate insulating film 3, a first semiconductor film (a-Si) 4, a second semiconductor film (N + a-Si) 5, a source / drain metal film 6, and a positive photoresist film 7 are formed (FIG. 3). (A)).

  Next, the positive photoresist film 7 is exposed and developed using a gray tone mask 100 having a light shielding portion 101, a light transmitting portion 102, and a semi-light transmitting portion (gray tone portion) 103, thereby developing a TFT channel. A first resist pattern 7A is formed so as to cover the portion and the source / drain formation region and the data line formation region, and to make the TFT channel portion formation region thinner than the source / drain formation region (FIG. 3B).

  Next, the source / drain metal film 6 and the second and first semiconductor films 5 and 4 are etched using the first resist pattern 7A as a mask (FIG. 3C). Next, the resist film 7 is entirely reduced by ashing with oxygen to remove the thin resist film in the channel portion formation region, thereby forming a second resist pattern 7B (FIG. 4A). Thereafter, using the second resist pattern 7B as a mask, the source / drain metal film 6 is etched to form the source / drains 6A and 6B, and then the second semiconductor film 5 is etched (FIG. 4B). Finally, the remaining second resist pattern 7B is peeled off (FIG. 4C).

  The gray tone mask 100 used here is the same mask as the gray tone mask 200 shown in FIG. The gray tone mask 200 includes a light shielding film 101, a translucent portion 102, and a gray tone portion 103. As described in Patent Document 1, the gray tone portion 103 is composed of a light semi-transmissive halftone film (semi-transmissive film). By using this semi-transparent film, halftone exposure can be performed with a reduced exposure amount by the gray tone portion 103.

  Since the gray tone portion 103 is composed of a semi-transparent film, it is only necessary to consider how much the entire transmittance is necessary in the design. In the production of the gray tone mask 200, the film of the semi-transparent film is sufficient. The gray tone mask 200 can be produced simply by selecting the seed (film material) and film thickness. Therefore, in the production of the gray tone mask 200, it is sufficient to control the thickness of the semi-transparent film, and the management is relatively easy. In addition, when the TFT channel portion is formed by the gray tone portion 103 of the gray tone mask 200, the semi-transparent film 103 can be easily patterned by a photolithography process, so that the shape of the TFT channel portion is also complicated. Is possible.

  In manufacturing the gray tone mask 200 as described above, first, a mask blank 107 in which a semi-transparent film 105 and a light-shielding film 106 are sequentially formed on a light-transmitting substrate 104 is prepared (FIG. 5A). As the semi-transparent film 105, a film containing molybdenum and silicon, for example, a MoSi film is used. The light shielding film 106 is a film containing, for example, chromium as a main component.

  Next, a first resist pattern 108 is formed on the light shielding film 106 of the mask blank 106 with the light transmitting portion 102 as an opening region (FIG. 5B). Then, using the first resist pattern 108 as a mask, the light shielding film 106 is etched using a chromium etching solution to form a light shielding film pattern 109 (FIG. 5C). Thereafter, similarly, using the first resist pattern 108 as a mask, the translucent film 105 is etched using an etching solution for MoSi to form a translucent portion 102 (FIG. 5D). After the formation of the light transmitting portion 102, the remaining first resist pattern 108 is peeled off (FIG. 5E).

  Next, a second resist pattern 110 having the gray tone portion 103 as an opening region is formed on the light-shielding film pattern 109 (FIG. 5F), and the chromium etching solution is formed using the second resist pattern 110 as a mask. Then, the light shielding film 106 is etched to form the light shielding portion 101 and the gray tone portion 103 (FIG. 5G). Finally, the remaining second resist pattern 110 is removed to manufacture the gray tone mask 200 (FIG. 5H).

JP 2002-189280 A

  As described above, when manufacturing the gray tone mask 200 in which the gray tone portion 103 is made of the semi-transparent film 105, as shown in FIG. 5D, the first resist pattern 108 is used as a mask for the MoSi mask. The semi-transparent film 105 (MoSi film) is wet etched using an etching solution. At this time, the resist of the first resist pattern 108 and the MoSi etchant may chemically react to generate foreign matter. This foreign matter may be generated on the light-transmitting substrate 104 shown in FIG. Adhering to the light shielding film 106 of the film pattern 109 is inconvenient.

  As a resist for forming the first resist pattern 108, for example, a novolac resist is often used. This is because novolak resists are advantageous from the viewpoint of mass productivity and low cost. The etching solution for MoSi includes at least one fluorine compound selected from hydrofluoric acid, silicohydrofluoric acid, and ammonium hydrogen fluoride, and at least one oxidizing agent selected from hydrogen peroxide, nitric acid, and sulfuric acid. In many cases, an etching solution containing s is used. However, depending on the combination of the type of resist and the components contained in the etching solution, the resist and the etching solution may chemically react to generate foreign substances mainly composed of fluoride-based organic substances. Once these foreign substances adhere to the light-transmitting substrate 104 or the light-shielding film 106, it is very difficult to remove them even if they are cleaned by a normal acid cleaning or alkali cleaning.

  Further, when the resist comes into contact with the etching solution, the adhesion to the light shielding film 106 often decreases, and the resist is easily peeled off during etching. The peeled resist may float in the etching solution and reattach to the substrate as a foreign substance. In many cases, the reattached foreign matter is likely to adhere firmly to the substrate because the organic matter is generated by reaction with the etching solution.

  The object of the present invention has been made in consideration of the above-described circumstances, and pattern formation that can prevent foreign matter generated by contact of a resist with an etching solution from adhering to a substrate or a film on the substrate. It is to provide a method and a method of manufacturing a gray-tone mask.

  A pattern forming method according to an invention of claim 1 is a pattern forming method including a step of patterning a thin film containing metal and silicon formed on a substrate by etching, wherein the thin film is etched on the thin film. A step of forming an inorganic etching mask layer having resistance, a step of forming a desired resist pattern on the inorganic etching mask layer, and the inorganic etching mask layer using the resist pattern as a mask. Etching with an etching solution for an inorganic etching mask layer whose thin film has etching resistance, a step of removing the remaining resist pattern after etching the inorganic etching mask layer, and the inorganic etching mask layer Using the above as a mask and using an etching solution for thin film Etching the film, it is characterized in that it has a, and removing the non-desired portion of the inorganic-based etching mask layer.

  A pattern forming method according to a second aspect of the present invention is the pattern forming method according to the first aspect, wherein the thin film containing metal and silicon is a thin film containing molybdenum and silicon.

  A pattern forming method according to a third aspect of the present invention is the pattern forming method according to the first or second aspect, wherein the inorganic etching mask layer is a film containing chromium as a main component. .

  A pattern forming method according to a fourth aspect of the present invention is the pattern forming method according to any one of the first to third aspects, wherein the thin film etching solution is hydrofluoric acid, silicohydrofluoric acid, or ammonium hydrogen fluoride. And at least one oxidant selected from hydrogen peroxide, nitric acid, and sulfuric acid.

According to a fifth aspect of the present invention, there is provided a gray-tone mask manufacturing method, comprising: a light-blocking portion; a light-transmitting portion; and a gray-tone mask having a gray-tone portion that reduces the amount of exposure light used when the mask is used. In the method, a step of preparing a mask blank in which a thin film containing metal and silicon and an inorganic etching mask layer, which are resistant to mutual etching, are sequentially formed on a transparent substrate, and the inorganic etching mask described above Forming a first resist pattern on the layer with the light-transmitting portion as an opening region; and using the first resist pattern as a mask, the inorganic etching mask layer is etched with an inorganic etching mask layer etchant. And etching, and after etching the inorganic etching mask layer, the remaining first resist pattern is removed. Using the inorganic etching mask layer as a mask, etching the thin film using a thin film etching solution to form the light transmitting portion, and the inorganic etching mask layer and the light transmitting substrate. A step of forming a second resist pattern having the gray tone portion as an opening region; and etching the inorganic etching mask layer using the second resist pattern as a mask, and then removing the second resist pattern. And forming the gray tone portion made of the thin film, the inorganic etching mask layer, and the light shielding portion made of the thin film, respectively.

  A graytone mask manufacturing method according to a sixth aspect of the invention is characterized in that, in the fifth aspect of the invention, the thin film containing metal and silicon is a translucent film containing molybdenum and silicon. To do.

  A gray-tone mask manufacturing method according to a seventh aspect of the invention is characterized in that, in the invention according to the fifth or sixth aspect, the inorganic etching mask layer is a light shielding film containing chromium as a main component. To do.

  According to an eighth aspect of the present invention, there is provided a gray-tone mask manufacturing method according to any one of the fifth to seventh aspects, wherein the thin film etching solution is hydrofluoric acid, silicohydrofluoric acid, It contains at least one fluorine compound selected from ammonium hydride and at least one oxidizing agent selected from hydrogen peroxide, nitric acid, and sulfuric acid.

  A graytone mask manufacturing method according to a ninth aspect of the invention is characterized in that, in the invention according to any one of the fifth to eighth aspects, the graytone mask is a mask for manufacturing a liquid crystal display device. Is.

  A tenth aspect of the present invention is a pattern transfer method including a step of exposing exposure light onto a transfer object using the gray tone mask according to the above manufacturing method.

  According to the invention of any one of claims 1 to 10, after the resist pattern (first resist pattern) is peeled off, the thin film containing metal and silicon is removed using the inorganic etching mask layer as a mask. Thus, the resist of the resist pattern (first resist pattern) and the thin film etching solution are not chemically reacted to generate foreign matter. Therefore, it is possible to reliably prevent the foreign matter from adhering to the substrate and the film on the substrate, and an excellent transfer pattern can be obtained.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a process diagram showing an embodiment of a method for manufacturing a gray-tone mask according to the present invention. 2A and 2B show a gray-tone mask manufactured by the gray-tone mask manufacturing method of FIG. 1, in which FIG. 2A is a plan view and FIG. 2B is a side sectional view.

  A gray tone mask 10 shown in FIG. 2 is used for manufacturing, for example, a thin film transistor (TFT), a color filter, a plasma display panel (PDP), or the like of a liquid crystal display (LCD). In addition, the resist patterns 12 having different film thicknesses are formed stepwise or continuously. In FIG. 2B, reference numerals 19A and 19B denote films stacked on the transfer object 11. The gray tone mask 10 has a size of, for example, 300 × 300 mm or more. In addition, the present embodiment can be suitably applied even when the size of one side exceeds 1000 mm with the increase in the size of current display devices.

Specifically, the gray tone mask 10 includes a light shielding portion 13 that shields exposure light (transmittance is approximately 0%) when the gray tone mask 10 is used, and a light transmitting portion 14 that transmits approximately 100% of the exposure light. And a gray tone portion 15 that reduces the transmittance of exposure light to about 10 to 60%. The gray tone portion 15 is configured by providing a translucent semi-transparent film 17 on the surface of a translucent substrate 16 such as a glass substrate. Further, the light shielding portion 13 is configured by sequentially providing the semi-transparent film 17 and the light shielding film 18 on the surface of the light transmissive substrate 16.

  The translucent film 17 is a thin film containing metal and silicon, and examples of the metal include molybdenum, tungsten, tantalum, vanadium, niobium, cobalt, zirconium, nickel, and the like. Among these, molybdenum is preferable. Therefore, the semi-transparent film 17 of the present embodiment is a film containing MoSi as a component. When carbon is contained in the semi-transparent film of the present application, the etching efficiency of the semi-transparent film is likely to be hindered. Further, when nitrogen or oxygen is contained in the semi-transparent film of the present application, there is a concern that the cleaning liquid resistance of the gray tone mask is lowered. Therefore, the semi-transparent film 17 of this embodiment is preferably a film substantially made of molybdenum and silicon. In addition, the case where the sputtering gas (for example, Ar) at the time of film-forming of a semi-transparent film is contained as an impurity is not prevented.

  Further, the light shielding film 18 is mainly composed of chromium, and becomes an inorganic etching mask layer that functions as a mask when the semi-transparent film 17 is etched in the manufacturing process of the gray tone mask 10 as described later. Note that the light-shielding film containing chromium as a main component may contain nitrogen, oxygen, and carbon. It is preferable to add nitrogen, oxygen, and carbon to the light-shielding film containing chromium as a main component because the antireflection function and the like are provided to the gray tone mask 10. The light transmittance of the light shielding portion 13 and the gray tone portion 15 is set by selecting the film material and film thickness of the semi-transparent film 17 and the light shielding film 18.

  When the gray tone mask 10 as described above is used, the exposure light is not transmitted through the light shielding portion 13, and the exposure light is reduced at the gray tone portion 15. Therefore, for example, when a positive resist film is attached on the transfer target 11 and the resist film is exposed using the gray tone mask 10 described above, the resist film attached on the transfer target 11 is: A film thickness is increased at a portion corresponding to the light shielding portion 13, a film thickness is decreased at a portion corresponding to the gray tone portion 15, and a film having no film is formed at a portion corresponding to the light transmitting portion 14.

  Then, first etching is performed on, for example, the films 19A and 19B in the transferred object 11 at a portion where the film of the resist pattern 12 does not have a film, and a thin part of the film of the resist pattern 12 is removed by ashing or the like. For example, the second etching is performed on the film 19 </ b> B in the body 11. In this way, a process for two conventional photomasks is performed using one gray-tone mask 10, and the number of masks is reduced.

  A manufacturing process for manufacturing the gray tone mask 10 as described above will be described below with reference to FIG.

First, a mask blank 20 is formed by performing a process of sequentially forming a semi-transparent film 17 and a light-shielding film 18 on the surface of the translucent substrate 16 (FIG. 1A). The semi-transparent film 17 can be formed by sputtering film formation using, for example, a sputtering target made of MoSi ₂ and using argon as a sputtering gas. The film thickness is appropriately selected depending on the required transmissivity of the semipermeable membrane. Next, the light shielding film 18 is a single layer or multi-layered film (for example, a light shielding film with an antireflection film) by reactive sputtering using a reactive gas such as nitrogen, oxygen, methane, and carbon dioxide using a chromium target, for example. ) Can be formed.
The semi-transparent film 17 and the light shielding film 18 have resistance to mutual etching in the manufacturing process of the gray tone mask 10. That is, the semi-transparent film 17 has a predetermined resistance or more with respect to the chromium etching solution as the inorganic etching layer etching solution. Further, the light shielding film 18 has a predetermined resistance or more with respect to an etching solution for MoSi as an etching solution for a thin film containing metal and silicon.

  Next, a resist film (positive resist film) is formed on the light shielding film 18 of the mask blank 20, and the resist film is exposed using an electron beam or a laser drawing apparatus, and developed with a developer. A resist pattern 21 is formed (FIG. 1B). The first resist pattern 21 is formed in a shape having the light transmitting portion 14 of the manufactured gray-tone mask 10 as an opening region. In addition, as the resist for forming the first resist pattern 21, a novolak resist can be used.

  The mask blank 20 on which the first resist pattern 21 is formed is immersed in an etching solution for chromium, and the etching solution for chromium is used to wet-etch the light shielding film 18 of the mask blank 20 using the first resist pattern 21 as a mask. (FIG. 1C). By this etching, a light shielding film pattern 22 is formed on the light shielding film 18. At this time, as the chromium etching solution, for example, an etching solution containing second cerium ammonium nitrate to which perchloric acid is added can be used. Moreover, the semi-transparent film 17 has a predetermined resistance or more with respect to the chromium etching solution. Furthermore, it is preferable that the resist constituting the first resist pattern 21 is not stripped by the chromium etching solution.

  After the formation of the light shielding film pattern 22, the first resist pattern 21 remaining on the light shielding film pattern 22 is peeled off (FIG. 1D). The resist can be peeled off by supplying a developing solution to the main surface in a spray state with the mask substrate tilted. Preferably, the developing solution supply means and the mask substrate are relatively moved (preferably swayed) so that the removed resist is completely removed from the mask substrate.

  After the first resist pattern 21 is peeled off, the mask blank 20 on which the light shielding film pattern 22 is formed is brought into contact with an etching solution for MoSi, and this semi-transparent film is used with the light shielding film pattern 22 as a mask. 17 is wet-etched to form a semi-transparent film pattern 23 (FIG. 1E). As a method of bringing the mask blank 20 into contact with the etching solution, the mask blank 20 may be immersed in the etching solution, or the etching solution may be supplied to the inclined main surface of the mask blank 20 in a spray form. Although the embodiment of the present invention can be suitably used for a large graytone mask 10 used when manufacturing a display device having a side of 300 mm or more, such a large graytone mask. In particular, the method of supplying the etching solution in a spray form is particularly advantageous. The light-transmitting portion 14 is formed by the light shielding film pattern 22 and the semi-transparent film pattern 23.

  The etching solution for MoSi is, for example, at least one fluorine compound selected from hydrofluoric acid, hydrosilicofluoric acid, and ammonium hydrogen fluoride, and at least one oxidation selected from, for example, hydrogen peroxide, nitric acid, and sulfuric acid. Agent. As the fluorine compound, ammonium hydrogen fluoride is preferable because it does not damage the transparent substrate. At this time, it is preferable to use hydrogen peroxide as an oxidizing agent. The light shielding film 18 has a predetermined resistance or more with respect to the MoSi etching solution. Since the semi-transparent film 17 is etched with the MoSi etching solution using the light shielding film pattern 22 made of the light shielding film 18 as an etching mask, a chemical reaction occurs between the resist constituting the first resist pattern 21 and the MoSi etching solution. As a result, no foreign matter composed of a fluoride organic material is produced.

  After forming the semi-transparent film pattern 23 as described above, a step of removing portions other than the desired portions of the light shielding film 18 constituting the light shielding film pattern 22 is performed. That is, a resist film is formed on the light shielding film pattern 22 and the translucent substrate 16, and this resist film is exposed and developed in the same manner as described above to form the second resist pattern 24 (FIG. 1F). ). The second resist pattern 24 is formed in a shape having the gray tone portion 15 as an opening region. Next, using the second resist pattern 24 as a mask, the light shielding film 18 constituting the light shielding film pattern 22 is further wet etched using the chromium etching solution (FIG. 1G).

  Thereafter, the remaining second resist pattern 24 is peeled off, and the gray tone mask 10 having the gray tone portion 15 made of the semi-transparent film 17, the light shielding portion 13 in which the light shielding film 18 and the semi-transparent film 17 are laminated is formed. Manufacture (FIG. 1 (H)).

With the configuration as described above, according to the above embodiment, the following effects are obtained.
In the manufacturing process of the gray tone mask 10, as shown in FIG. 1D, after the first resist pattern 21 is peeled off, the semi-transparent film 17 (MoSi film) is etched for MoSi using the light shielding film pattern 22 as a mask. Etching with a solution. For this reason, the resist of the first resist pattern 21 and the MoSi etching solution do not chemically react to generate foreign matter. Therefore, the foreign matter is shielded from light on the translucent substrate 16 and the light shielding film pattern 22. It is possible to reliably prevent adhesion on the film 18.

  Further, when the gray tone mask 10 is used, the gray tone mask 10 is irradiated with light from an exposure machine, and light (exposure light) that has passed through the gray tone mask 10 is exposed on the transfer object, thereby producing gray. It is possible to provide a pattern transfer method for transferring a pattern formed on the tone mask 10 onto a transfer target. Here, since the gray tone mask 10 includes the light shielding portion 13, the light transmitting portion 14, and the gray tone portion 15, the film thickness of the resist pattern formed on the transfer target is partially set. For example, when manufacturing a TFT substrate, the number of photomasks to be used can be reduced.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this.

It is process drawing which shows one Embodiment in the manufacturing method of the gray tone mask which concerns on this invention. 1A and 1B show a gray-tone mask manufactured by the gray-tone mask manufacturing method of FIG. 1, in which FIG. 1A is a plan view and FIG. It is process drawing which shows the manufacturing process of the TFT substrate using a gray tone mask. FIG. 4 is a process diagram illustrating a continuation of the manufacturing process of FIG. 3. It is process drawing which shows the manufacturing method of the conventional gray tone mask.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Gray tone mask 13 Light-shielding part 14 Light transmission part 15 Gray tone part 17 Semi-transparent film 18 Light-shielding film 20 Mask blank 21 1st resist pattern 22 Light-shielding film pattern 23 Semi-transparent film pattern 24 2nd resist pattern

Claims (10)

In a pattern forming method including a step of patterning a thin film containing metal and silicon formed on a substrate by etching,
Forming an inorganic etching mask layer having resistance to etching of the thin film on the thin film;
Forming a desired resist pattern on the inorganic etching mask layer;
Etching the inorganic etching mask layer using the resist pattern as a mask, using an etching solution for an inorganic etching mask layer in which the thin film has etching resistance;
Removing the remaining resist pattern after etching the inorganic etching mask layer;
Etching the thin film using a thin film etchant using the inorganic etching mask layer as a mask;
Removing other than the desired portion of the inorganic etching mask layer;
The pattern formation method characterized by having. The pattern forming method according to claim 1, wherein the thin film containing metal and silicon is a thin film containing molybdenum and silicon. The pattern forming method according to claim 1, wherein the inorganic etching mask layer is a film containing chromium as a main component. The thin film etching solution includes at least one fluorine compound selected from hydrofluoric acid, hydrosilicofluoric acid, and ammonium hydrogen fluoride, and at least one oxidizing agent selected from hydrogen peroxide, nitric acid, and sulfuric acid. The pattern forming method according to claim 1, wherein: In a method of manufacturing a gray tone mask having a light shielding portion, a light transmitting portion, and a gray tone portion that reduces the amount of exposure light transmitted when the mask is used,
A step of preparing a mask blank in which a thin film containing metal and silicon and an inorganic etching mask layer, which are resistant to mutual etching, are sequentially formed on a translucent substrate;
Forming a first resist pattern having the light transmitting portion as an opening region on the inorganic etching mask layer;
Etching the inorganic etching mask layer with an inorganic etching mask layer etchant using the first resist pattern as a mask;
A step of peeling off the remaining first resist pattern after etching the inorganic etching mask layer;
Etching the thin film with a thin film etchant using the inorganic etching mask layer as a mask to form the light transmitting part; and
Forming a second resist pattern having the gray tone portion as an opening region on the inorganic etching mask layer and the translucent substrate;
Using the second resist pattern as a mask, the inorganic etching mask layer is etched, and then the second resist pattern is peeled off to form the gray tone portion made of the thin film, the inorganic etching mask layer, and the thin film. And a step of forming each of the light shielding portions. 6. The method of manufacturing a gray-tone mask according to claim 5, wherein the thin film containing metal and silicon is a translucent film containing molybdenum and silicon. The method for producing a gray-tone mask according to claim 5 or 6, wherein the inorganic etching mask layer is a light shielding film containing chromium as a main component. The thin film etching solution includes at least one fluorine compound selected from hydrofluoric acid, hydrosilicofluoric acid, and ammonium hydrogen fluoride, and at least one oxidizing agent selected from hydrogen peroxide, nitric acid, and sulfuric acid. The method for manufacturing a gray-tone mask according to claim 5, wherein: 9. The method of manufacturing a gray tone mask according to claim 5, wherein the gray tone mask is a mask for manufacturing a liquid crystal display device.   A pattern transfer method comprising a step of exposing exposure light onto a transfer object using the gray tone mask according to the manufacturing method of claim 9.

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