Positive photoresist composition and method for forming photoresist pattern

Abstract

The invention provides a positive photoresist composition. The positive photoresist composition comprises phenolic resin, a photosensitizer, an acid generator, a cross-linking agent, an additive and a solvent. The positive photoresist composition provided by the embodiment of the invention at least can be used for a high-temperature-resistant positive photoresist layer, so that the high-temperature stability and the heat resistance of the positive photoresist layer are remarkably improved. In accordance with an embodiment of the present application, a method of forming a photoresist pattern using the positive photoresist composition is also provided. According to the embodiment of the invention, at least the high-temperature-resistant photoresist pattern can be obtained.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and more specifically, to a photoresist composition and its application, and in particular to a positive photoresist composition and a method for forming a photoresist pattern. Background Art

[0002] Photoresist, also known as photoresist, is a key photosensitive material in the semiconductor and panel manufacturing process. It is generally composed of resin, photosensitizer, solvent and additives. In practice, people classify photoresists according to different classification methods. According to the mechanism of action, it can be divided into positive photoresist and negative photoresist. When positive photoresist is irradiated by a light source of a specific wavelength, the exposed area undergoes chemical changes due to the light, which significantly increases the dissolution rate of the exposed area of ​​the photoresist in the developer. After development, the photoresist in the exposed area is removed, and the same pattern as the mask is formed on the substrate; while the mechanism of action of negative photoresist is the opposite. When negative photoresist is irradiated by a light source of a specific wavelength, the exposed area undergoes a cross-linking reaction due to the light, which rapidly decreases the dissolution rate of the exposed area of ​​the photoresist in the developer. After development, the photoresist in the exposed area is retained, forming a pattern opposite to the mask on the substrate. According to the application field classification, photoresist can be roughly divided into PCB photoresist, panel photoresist, semiconductor photoresist and other types of photoresist. Depending on the wavelength of the required exposure light source, photoresists are divided into ultraviolet full-spectrum photoresists (300-450nm), g-line (436nm), h-line (405nm), i-line (365nm), KrF (248nm), ArF (192nm) and EUV (13.5nm) photoresists.

[0003] At present, g, h, and i-line photoresists mainly use phenolic resin as the film-forming material. The common i-line positive photoresists on the market are mainly phenolic resin system photoresists. The positive photoresist composition is mainly composed of phenolic resin, photosensitizer, solvent, etc., and has the advantages of good resolution and small graphic distortion, but poor heat resistance. In the semiconductor photolithography process, in order to remove residual solvents in the photoresist and improve the adhesion, etching resistance and other properties of the photoresist, a hard baking process (hard film baking) is often added after development. Although the hard baking temperature is usually between 100°C-130°C, due to certain process requirements, the hard baking temperature is sometimes required to be 180°C or higher.

[0004] Since ordinary positive photoresists have poor high temperature resistance, especially when the film thickness is greater than 5um, the hard baking temperature is high, for example, above 150°C, the graphic morphology cannot be maintained and obvious collapse occurs, making them unsuitable for application in semiconductor lithography processes. Summary of the invention

[0005] In view of the above problems existing in the prior art, an embodiment of the present application proposes a positive photoresist composition, which can at least be used for a high-temperature resistant positive photoresist layer to significantly improve the high-temperature stability and heat resistance of the positive photoresist layer.

[0006] According to one aspect of the present application, a positive photoresist composition is provided, which includes: a phenolic resin, a photosensitizer, an acid generator, a cross-linking agent, an additive and a solvent.

[0007] In some embodiments, the acid generator generates acid when stimulated by external stimuli to promote the cross-linking reaction between the phenolic resin and the cross-linking agent.

[0008] In some embodiments, the external stimulus is light or heat.

[0009] In some embodiments, based on the total mass of the positive photoresist composition, the mass percentage of the phenolic resin is 5%-40%, the mass percentage of the photosensitizer is 0.5%-10%, the mass percentage of the acid generator is 0.01%-2%, the mass percentage of the cross-linking agent is 0.1%-20%, the mass percentage of the additive is 0.01%-10%, and the mass percentage of the solvent is 50%-90%.

[0010] In some embodiments, the phenolic resin includes one or more of phenol resin, cresol phenolic resin, xylenol-cresol phenolic resin, and tricresol-cresol phenolic resin.

[0011] In some embodiments, the crosslinking agent is a melamine resin containing an ether bond substituent, and the molecular structure is shown in Formula 1, wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 Each independently represents -H, -OH, -CH3, -CH2OH, -CH2CH2OH, -CH2OCH3, -CH2CH2OCH3, -OCH3, -OCH2CH3, R 1 -R 6 The substituent contains multiple ether bonds, and the number of ether bonds of the cross-linking agent is 2-6:

[0012] Formula 1.

[0013] In some embodiments, the photosensitizer is selected from diazoquinone photosensitizers.

[0014] In some embodiments, the acid generator is selected from one or more of iodonium salts, sulfonium salts, and heterocyclic acid generators.

[0015] In some embodiments, the solvent is an organic solvent, including one or more of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, benzyl alcohol, n-butyl acetate, methyl methoxypropionate, ethyl lactate, ethyl ethoxypropionate, diethylene glycol methyl ethyl ether, benzyl alcohol, and diethylene glycol methyl ethyl ether.

[0016] In some embodiments, the additive includes a silicone ether surfactant and / or a fluorine-containing surfactant.

[0017] In some embodiments, the silicone ether surfactant is selected from one or more of polyether siloxane copolymers, polyether modified siloxane copolymers, and polyester modified polydimethylsiloxane copolymers, and the fluorine-containing surfactant is selected from one or more of fluorocarbon carboxylate surfactants, perfluorocarbon sulfonate surfactants, and perfluorocarbon phosphate surfactants.

[0018] Another object of the present application is to provide a method for forming a photoresist pattern using a positive photoresist composition, wherein the positive photoresist composition is any one of the positive photoresist compositions mentioned above.

[0019] In some embodiments, the method of forming a photoresist pattern comprises the following steps:

[0020] (1) providing a substrate, wherein the surface of the substrate includes one or more layers to be patterned, and adding any one of the above-mentioned positive photoresist compositions on the layers to be patterned to form a positive photoresist composition layer;

[0021] (2) pre-baking the positive photoresist composition layer;

[0022] (3) exposing the positive photoresist composition layer to actinic radiation through a photolithography device;

[0023] (4) placing the exposed positive photoresist composition layer in a developer for development to obtain a photoresist pattern;

[0024] (5) The obtained photoresist pattern is hardened by baking.

[0025] In some embodiments, the pre-baking temperature in step (2) is in the range of 80-120°C, and the baking time is 60s-180s. In step (3), a single wavelength light source or a mixed wavelength light source with a wavelength in the range of 350-450nm is used for actinic radiation exposure. In step (4), a tetramethylammonium hydroxide aqueous solution with a temperature of 23-25°C and a concentration in the range of 1.83%-3.5% is used for development for 60s-200s. In step (5), the hardening film baking temperature is in the range of 90-140°C, and the baking time is 2-10 minutes.

[0026] The beneficial technical effects of this application are:

[0027] The present application provides a positive photoresist composition comprising a phenolic resin, a photosensitizer, an acid generator, and a cross-linking agent, etc., which can be used at least for a high-temperature resistant positive photoresist layer to significantly improve the high-temperature stability and heat resistance of the positive photoresist layer. In the embodiments of the present application, the acid generator in the positive photoresist composition generates acid when stimulated by external stimuli to promote the cross-linking reaction between the phenolic resin and the cross-linking agent, increase the degree of cross-linking, and significantly improve the heat resistance of the photoresist.

[0028] The present application provides a method for forming a photoresist pattern using any one of the above-mentioned positive photoresist compositions, which can at least obtain a high-temperature resistant photoresist pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a scanning electron microscope image of the photoresist pattern obtained in Example 1 after the heat resistance test.

[0030] Figure 2 This is a scanning electron microscope image of the photoresist pattern obtained in Example 2 after the heat resistance test.

[0031] Figure 3 This is a scanning electron microscope image of the photoresist pattern obtained in Comparative Example 1 after heat resistance testing.

[0032] Figure 4 This is a scanning electron microscope image of the photoresist pattern obtained in Comparative Example 4 after heat resistance testing. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present application clearer and more understandable, and to fully convey the scope of the present application to those skilled in the art, the exemplary embodiments are fully described in detail below. However, these exemplary embodiments can be implemented in different ways and should not be construed as being limited to the embodiments described in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application. It should be understood that the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0034] The present application provides a positive photoresist composition, which includes a phenolic resin, a photosensitizer, an acid generator, a cross-linking agent, an additive and a solvent. Compared with the technical solution of the prior art that the positive photoresist composition includes a phenolic resin, a photosensitizer and a solvent, the positive photoresist composition proposed in the present application also includes an acid generator and a cross-linking agent. That is to say, the present application provides a new technical solution, and the positive photoresist composition includes a phenolic resin, a photosensitizer, an acid generator and a cross-linking agent at the same time. The positive photoresist composition of the present application can at least be used for a high-temperature resistant positive photoresist layer to significantly improve the high-temperature stability and heat resistance of the positive photoresist layer. Among them, the acid generator can produce acid, and the acid causes the phenolic resin to undergo a cross-linking reaction with the cross-linking agent to increase the degree of cross-linking. The photosensitizer will chemically decompose after being exposed to form a solubility enhancer, so that the photoresist can be dissolved in the developer.

[0035] In some embodiments, the acid generator generates acid when it is stimulated by an external stimulus, so as to promote the cross-linking reaction between the phenolic resin and the cross-linking agent, increase the degree of cross-linking, and significantly improve the heat resistance of the photoresist. In some embodiments, the external stimulus can be light or heat, that is, the acid generator can generate acid when it is stimulated by light or under heating / temperature-raising conditions. It should be understood that the external stimulus can also be any other stimulus other than light or heat that can cause the acid generator to generate acid.

[0036] In some embodiments, the mass of the phenolic resin is 5%-40% of the total mass of the positive photoresist composition, the mass of the photosensitizer is 0.5%-10% of the total mass of the positive photoresist composition, the mass of the acid generator is 0.01%-2% of the total mass of the positive photoresist composition, the mass of the cross-linking agent is 0.1%-20% of the total mass of the positive photoresist composition, the mass of the additive is 0.01%-10% of the total mass of the positive photoresist composition, and the mass of the solvent is 50%-90% of the total mass of the positive photoresist composition.

[0037] Specifically, the mass of the phenolic resin can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40% of the total mass of the positive photoresist composition; the mass of the photosensitizer can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% of the total mass of the positive photoresist composition; the mass of the acid generator can be 0.01%, 0.05%, 0.1%, 0.5%, 1.0%, 1.5%, or 2% of the total mass of the positive photoresist composition; the mass of the cross-linking agent can be 0.1%, 1%, 5%, 10%, 15%, or 20% of the total mass of the positive photoresist composition; the mass of the additive can be 0.01%, 1%, 3%, 5%, 7%, or 10% of the total mass of the positive photoresist composition; and the mass of the solvent can be 50%, 60%, 70%, 80%, or 90% of the total mass of the positive photoresist composition.

[0038] Among them, when the content of the acid generator is less than 0.01%, the acidic environment required for the crosslinking agent reaction cannot be generated, and the heat resistance of the photoresist cannot be increased by crosslinking. When the content of the acid generator is greater than 2%, a small amount of the acid generator will be decomposed due to heat during the pre-bake to form the photoresist pattern. The acid generator produces too much acid during the pre-bake, and the photoresist is cross-linked and the degree of cross-linking is too high, resulting in the exposed part of the photoresist being unable to dissolve in the developer during development. Therefore, the content of the acid generator is set at 0.01%-2%, which will not cause the acid generator to produce too much acid during the pre-bake and cause excessive cross-linking, and after exposure, acid can be produced to cause the phenolic resin to undergo a cross-linking reaction with the cross-linking agent, thereby increasing the degree of cross-linking and thereby improving the heat resistance of the positive photoresist layer.

[0039] Preferably, the mass of the acid generator may be 0.01%-0.5% of the total mass of the positive photoresist composition.

[0040] The present application adopts phenolic resin as the main resin. In some embodiments, the selected phenolic resin includes one or more of phenol resin, cresol phenolic resin, dimethyl phenol-cresol phenolic resin, and trimethyl phenol-cresol phenolic resin. The content of dimethyl phenol in dimethyl phenol-cresol phenolic resin is 5%-30%, and the content of trimethyl phenol in trimethyl phenol-cresol phenolic resin is 5-30%. In some embodiments, the phenolic resin includes a high molecular weight resin and a low molecular weight resin, and the high molecular weight resin and the low molecular weight resin are used in combination, wherein the high molecular weight phenolic resin may preferably have a phenolic resin with a weight average molecular weight greater than 10,000, and the phenolic resin with a weight average molecular weight greater than 10,000 has a dissolution rate in the range of 20-300Å / s in a 2.38% tetramethylammonium hydroxide aqueous solution; the high molecular weight phenolic resin may preferably have a phenolic resin with a weight average molecular weight greater than 40,000, and the phenolic resin with a weight average molecular weight greater than 40,000 has a dissolution rate in the range of 20-300Å / s in a 2.38% tetramethylammonium hydroxide aqueous solution. The dissolution rate in aqueous solution is in the range of 50-150Å / s; the low molecular weight phenolic resin may preferably be a phenolic resin with a weight average molecular weight less than 10,000, and the dissolution rate of the phenolic resin with a weight average molecular weight less than 10,000 in a 2.38% tetramethylammonium hydroxide aqueous solution is greater than 1000Å / s; the low molecular weight phenolic resin may preferably be a phenolic resin with a weight average molecular weight less than 5,000, and the dissolution rate of the phenolic resin with a weight average molecular weight less than 5,000 in a 2.38% tetramethylammonium hydroxide aqueous solution is greater than 1500Å / s, and the present invention does not limit the use of other phenolic resins.

[0041] In some embodiments, the crosslinking agent may be a melamine resin containing an ether bond substituent, and the molecular structure is shown in Formula 1, wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 Each independently represents -H, -OH, -CH3, -CH2OH, -CH2CH2OH, -CH2OCH3, -CH2CH2OCH3, -OCH3, -OCH2CH3. In some embodiments, R 1 -R 6 The substituent may contain multiple ether bonds, and the number of ether bonds of the cross-linking agent is 2-6, preferably 4-6. Specifically, the number of ether bonds of the cross-linking agent may be 2, 3, 4, 5, or 6. The ether bonds in the cross-linking agent can cross-link with the hydroxyl groups in the phenolic resin under certain conditions, so the more ether bonds in the melamine resin, the better its cross-linking performance, which is conducive to increasing the degree of cross-linking.

[0042]

[0043] Formula 1

[0044] In some embodiments, the photosensitizer is selected from diazoquinone photosensitizers. In some embodiments, the diazoquinone photosensitizer is formed by esterification of polyhydroxybenzophenone and its analogs with 2-diazo-1-naphthoquinone-5-sulfonic acid (5-DNQ) or 2-diazo-1-naphthoquinone-4-sulfonic acid (4-DNQ). Specifically, the photosensitizer can be 2,3,4-trihydroxybenzophenone 1,2-diazide naphthoquinone-5-sulfonic acid ester.

[0045] In some embodiments, the acid generator is selected from one or more of iodonium salts, sulfonium salts, and heterocyclic acid generators. Specifically, the acid generator can be 4,4'-dimethylbenzene iodonium trifluoromethanesulfonate, bis(4-tert-butylphenyl)iodonium perfluoro-1-butanesulfonic acid, diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate, (4-phenylthiophenyl)diphenylsulfonium trifluoromethanesulfonate, diphenyl-4-tert-butylphenylsulfonium nonafluorobutanesulfonate, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-p-methoxyphenyl-1,3,5-triazine, and the like.

[0046] In some embodiments, the solvent may be an organic solvent, including one or more of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, benzyl alcohol, n-butyl acetate, methyl methoxypropionate, ethyl lactate, ethyl ethoxypropionate, diethylene glycol methyl ethyl ether, benzyl alcohol, and diethylene glycol methyl ethyl ether. However, the present application does not limit the solvent to only an organic solvent, and may be any solvent known to those skilled in the art that can play a role in dissolving the photoresist.

[0047] In some embodiments, the additive includes a silicone ether surfactant and / or a fluorine-containing surfactant. In some embodiments, the silicone ether surfactant is selected from one or more of a polyether siloxane copolymer, a polyether-modified siloxane copolymer, and a polyester-modified polydimethylsiloxane copolymer, and the fluorine-containing surfactant is selected from one or more of a fluorocarbon carboxylate surfactant, a perfluorocarbon sulfonate surfactant, and a perfluorocarbon phosphate surfactant.

[0048] In some embodiments, based on 100% total solid content of the photoresist composition, the added amount of the surfactant is preferably 200-10000 ppm, and more preferably 1000-5000 ppm.

[0049] The present application also provides a method for forming a photoresist pattern using a positive photoresist composition, wherein the positive photoresist composition is any one of the positive photoresist compositions mentioned above.

[0050] In some embodiments, the method of forming a photoresist pattern comprises the following steps:

[0051] (1) providing a substrate, wherein the surface of the substrate includes one or more layers to be patterned, and adding any one of the above-mentioned positive photoresist compositions on the layers to be patterned to form a positive photoresist composition layer;

[0052] (2) pre-baking the positive photoresist composition layer;

[0053] (3) exposing the positive photoresist composition layer to actinic radiation through a photolithography device;

[0054] (4) placing the exposed positive photoresist composition layer in a developer for development to obtain a photoresist pattern;

[0055] (5) The obtained photoresist pattern is hardened by baking.

[0056] The method of adding any one of the above positive photoresist compositions in step (1) comprises coating the positive photoresist composition on the corresponding substrate by spin coating or slit coating. The actinic radiation exposure in step (3) may use a mask.

[0057] The pre-baking process in the embodiment of the present application can cause part of the acid generator to decompose due to heat, and a small amount of acid causes the cross-linking agent in the positive photoresist composition layer to partially cross-link with the phenolic resin. After exposure, the photosensitizer in the exposed part of the photoresist is decomposed by light and converted into an acidic substance that is easily soluble in the developer. After development, the exposed part is dissolved in the developer, and the acid generator in the unexposed part slowly produces acid through hard film baking, further improving the degree of cross-linking of the unexposed part, thereby improving the heat resistance of the positive photoresist, so that the obtained photoresist pattern has excellent high temperature resistance, for example, it can withstand high temperature baking of 230-270°C, especially for thick glue layers greater than 10um, compared with ordinary positive photoresists without cross-linking agents and acid generators, the heat resistance is significantly improved. Among them, the acidic substance produced by the photosensitizer cannot effectively cause the cross-linking reaction between the resin and the cross-linking agent as an acidic catalyst. It is necessary to add an acid generator to produce a stronger acidic substance with obvious catalytic effect. The acid produced by the acid generator can promote dissolution to a certain extent, but as mentioned above, when the content of the acid generator is too much, the degree of cross-linking is too high, resulting in the exposed part of the photoresist being unable to dissolve in the developer during development. Therefore, the acid generator cannot replace the photosensitizer (similarly, the photosensitizer cannot play the role of the acid generator). For the unexposed part, part of the acid generator is stimulated (such as heat) to decompose and produce acid, while the photosensitizer is not exposed. The acid produced by the acid generator mainly plays a catalytic role for this part, and the effect of promoting dissolution is very weak. For the exposed part, the acid generator and the photosensitizer both decompose and produce acid, but because the amount of the photosensitizer is much larger than that of the acid generator, the effect of promoting dissolution is mainly brought by the photosensitizer.

[0058] The positive photoresist composition of the embodiment of the present application is a positive photoresist composition that can be used for g / i-line and g, h, i-broad spectrum.

[0059] In some embodiments, the pre-baking temperature in step (2) is in the range of 80-120°C, and the baking time is 60s-180s. In step (3), a single wavelength light source or a mixed wavelength light source with a wavelength in the range of 350-450nm is used for actinic radiation exposure. In step (4), a tetramethylammonium hydroxide aqueous solution with a temperature of 23-25°C and a concentration in the range of 1.83%-3.5% is used for development for 60s-200s. In step (5), the hardening film baking temperature is in the range of 90-140°C, and the baking time is 2-10 minutes.

[0060] The present application will be described in more detail below through examples.

[0061] Example 1

[0062] A positive photoresist composition, the composition of which is shown in Table 1:

[0063]

[0064] Table 1

[0065] The components in Table 1 were mixed uniformly according to the ratios shown in Table 1 to prepare a positive photoresist composition.

[0066] Forming a photoresist pattern using the positive photoresist composition of Table 1 comprises the following steps:

[0067] (1) coating the positive photoresist composition on a silicon wafer by spin coating at a rotation speed of 1000 rpm;

[0068] (2) pre-baking the positive photoresist composition layer at 100° C. for 120 seconds to obtain a photoresist composition layer with a film thickness of 15 μm;

[0069] (3) Using a mask, the positive photoresist composition layer baked in step (2) is placed in an i-line photolithography machine for actinic radiation exposure at an exposure rate of 400 mJ / cm 2 ;

[0070] (4) placing the positive photoresist composition layer after exposure in step (3) in a 2.38% TMAH developer for 120 seconds to obtain a photoresist pattern;

[0071] (5) After washing with deionized water, the photoresist pattern obtained in step (4) is hard-baked at 130° C. for 10 minutes to complete the photolithography process and obtain a high-temperature resistant photoresist pattern.

[0072] Example 2

[0073] A positive photoresist composition, the composition of which is shown in Table 2:

[0074]

[0075] Table 2

[0076] The components in Table 2 were mixed uniformly according to the ratios shown in Table 2 to prepare a positive photoresist composition.

[0077] The positive photoresist composition in Table 2 was used to form a photoresist pattern, and the steps were the same as those in Example 1.

[0078] Example 3

[0079] The difference from Example 1 is that the acid generator is reduced to a content of 0.01%.

[0080]

[0081] Table 3

[0082] The components in Table 3 were mixed uniformly according to the ratios shown in Table 3 to prepare a positive photoresist composition.

[0083] The positive photoresist composition in Table 3 was used to form a photoresist pattern, and the steps were the same as those in Example 1.

[0084] Example 4

[0085] The difference from Example 1 is that an acid generator is added so that the content of the acid generator is 2%.

[0086]

[0087] Table 4

[0088] The components in Table 4 were mixed uniformly according to the ratios shown in Table 4 to prepare a positive photoresist composition.

[0089] A photoresist pattern was formed using the positive photoresist composition in Table 4, and the steps were the same as those in Example 1.

[0090] Comparative Example 1

[0091] The only difference from Example 3 is that no acid generator is added.

[0092]

[0093] Table 5

[0094] The components in Table 5 were mixed uniformly according to the ratios shown in Table 5 to prepare a positive photoresist composition.

[0095] A photoresist pattern was formed using the positive photoresist composition in Table 5, and the steps were the same as those in Example 1.

[0096] Comparative Example 2

[0097] The only difference from Example 3 is that no photosensitizer is added.

[0098]

[0099] Table 6

[0100] The components in Table 6 were mixed uniformly according to the ratios shown in Table 6 to prepare a positive photoresist composition.

[0101] A photoresist pattern was formed using the positive photoresist composition in Table 6, and the steps were the same as those in Example 1.

[0102] Comparative Example 3

[0103] The difference from Example 3 is that no photosensitizer is added. In addition, the mass of the acid generator is made the same as the mass of the photosensitizer in Example 3.

[0104]

[0105] Table 7

[0106] The components in Table 7 were mixed uniformly according to the ratios shown in Table 7 to prepare a positive photoresist composition.

[0107] A photoresist pattern was formed using the positive photoresist composition of Table 7, and the steps were the same as those in Example 1.

[0108] Comparative Example 4

[0109] The only difference from Example 3 is that no crosslinking agent is added.

[0110]

[0111] Table 8

[0112] The components in Table 8 were mixed uniformly according to the ratios shown in Table 8 to prepare a positive photoresist composition.

[0113] A photoresist pattern was formed using the positive photoresist composition in Table 8, and the steps were the same as those in Example 1.

[0114] Comparative Example 5

[0115] The only difference from Example 3 is that no acid generator and cross-linking agent are added.

[0116]

[0117] Table 9

[0118] The components in Table 9 were mixed uniformly according to the ratios shown in Table 9 to prepare a positive photoresist composition.

[0119] A photoresist pattern was formed using the positive photoresist composition in Table 9, and the steps were the same as those in Example 1.

[0120] Comparative Example 6

[0121] The only difference from Example 3 is that an acid generator is added so that the content of the acid generator is 3% (exceeding 2%).

[0122]

[0123] Table 10

[0124] The components in Table 10 were mixed uniformly according to the ratios shown in Table 10 to prepare a positive photoresist composition.

[0125] A photoresist pattern was formed using the positive photoresist composition of Table 10, and the steps were the same as those in Example 1.

[0126] The photoresist patterns of the above-mentioned embodiments and comparative examples were subjected to heat resistance test baking in an oven for 30 minutes, and then the pattern changes were examined using a scanning electron microscope. The test results of the embodiments and comparative examples are shown in Table 11.

[0127]

[0128] Table 11

[0129] Figure 1 , Figure 2 , Figure 3 ,as well as Figure 4 The scanning electron microscope images of the photoresist patterns obtained in Example 1, Example 2, Comparative Example 1, and Comparative Example 4 after the heat resistance test are shown. It can be seen from the figure that the photoresist pattern made of the positive photoresist composition with the addition of an acid generator and a cross-linking agent is still strong after the heat resistance test, while the comparative example 1 without the addition of an acid generator has obvious collapse after the heat resistance test, and the comparative example 4 without the addition of a cross-linking agent has a more obvious collapse degree after the heat resistance test than the comparative example 1 without the addition of an acid generator.

[0130] In summary, the positive photoresist composition of the present application can at least be used for a high-temperature resistant positive photoresist layer. The positive photoresist composition of the present application is used to form a photoresist pattern, and the photoresist pattern has excellent high-temperature stability and heat resistance. For example, it can withstand high-temperature baking of 230-270°C without collapse.

[0131] It can be seen from Example 1, Example 3, Example 4, Comparative Example 1, and Comparative Example 6 that adding an acid generator with an acid generator content of 0.01%-2% can improve the high temperature stability of the positive photoresist layer, while when the acid generator content is 0 (no acid generator is added), a photoresist pattern can be formed under the same preparation conditions, but at 180°C, the photoresist pattern will collapse. When the acid generator content is greater than 2%, the degree of crosslinking is too high during the pre-bake process, resulting in an inability to develop and form a photoresist pattern.

[0132] It can be seen from Example 3, Comparative Example 1, Comparative Example 4, and Comparative Example 5 that, if no acid generator and / or cross-linking agent is added, although a photoresist pattern can be formed, the heat resistance of the photoresist pattern will decrease. Although Comparative Example 1 with a cross-linking agent but no acid generator has better heat resistance than Comparative Example 4 without a cross-linking agent, it still collapses at 180°C, which is lower than the temperature at which the collapse occurs in Example 3 (Example 3 still does not collapse at 230°C).

[0133] It can be seen from Example 3, Comparative Example 2, and Comparative Example 3 that when only an acid generator is added without a photosensitizer, the photoresist cannot form a pattern after exposure. Although the content of the acid generator in Comparative Example 3 is increased to the same level as the mass of the photosensitizer in Example 3, the photoresist still cannot form a pattern after exposure. That is, the acid generator plays the role of generating acid to promote the crosslinking reaction between the crosslinking agent and the phenolic resin. When there is only an acid generator but no photosensitizer, the acid generator cannot play the role of a photosensitizer. After exposure and development, the exposed part cannot be dissolved or cannot be dissolved completely to form a photoresist pattern.

[0134] The above embodiments are merely exemplary embodiments and are not intended to limit the present application. Various changes, substitutions and modifications may be made without departing from the spirit and scope of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A positive photoresist composition, characterized in that: The positive photoresist composition comprises a phenolic resin, a photosensitizer, an acid generator, a cross-linking agent, an additive and a solvent.

2. The positive photoresist composition according to claim 1, characterized in that The acid generator generates acid when stimulated by external stimuli to promote the cross-linking reaction between the phenolic resin and the cross-linking agent; Preferably, the external stimulus is light or heat.

3. The positive photoresist composition according to claim 1, characterized in that Based on the total mass of the positive photoresist composition, the mass percentage of the phenolic resin is 5%-40%, the mass percentage of the photosensitizer is 0.5%-10%, the mass percentage of the acid generator is 0.01%-2%, the mass percentage of the cross-linking agent is 0.1%-20%, the mass percentage of the additive is 0.01%-10%, and the mass percentage of the solvent is 50%-90%.

4. The positive photoresist composition according to claim 1, characterized in that The phenolic resin includes one or more of phenol resin, cresol phenolic resin, xylenol-cresol phenolic resin, and trimethylol-cresol phenolic resin.

5. The positive photoresist composition according to claim 1, characterized in that: The cross-linking agent is a melamine resin containing an ether bond substituent, and the molecular structure is shown in Formula 1: Formula 1 Among them, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 Each independently represents -H, -OH, -CH3, -CH2OH, -CH2CH2OH, -CH2OCH3, -CH2CH2OCH3, -OCH3, -OCH2CH3, R 1 -R 6 The substituent contains multiple ether bonds, and the number of ether bonds of the cross-linking agent is 2-6.

6. The positive photoresist composition according to claim 1, characterized in that: The photosensitizer is selected from diazoquinone photosensitizers; Preferably, the acid generator is selected from one or more of iodonium salts, sulfonium salts, and heterocyclic acid generators; Preferably, the solvent is an organic solvent, including one or more of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, benzyl alcohol, n-butyl acetate, methyl methoxypropionate, ethyl lactate, ethyl ethoxypropionate, diethylene glycol methyl ethyl ether, benzyl alcohol, and diethylene glycol methyl ethyl ether.

7. The positive photoresist composition according to claim 1, characterized in that: The additives include silicone ether surfactants and / or fluorine-containing surfactants; Preferably, the silicone ether surfactant is selected from one or more of polyether siloxane copolymers, polyether modified siloxane copolymers, and polyester modified polydimethylsiloxane copolymers, and the fluorine-containing surfactant is selected from one or more of fluorocarbon carboxylate surfactants, perfluorocarbon sulfonate surfactants, and perfluorocarbon phosphate surfactants.

8. A method for forming a photoresist pattern using a positive photoresist composition, characterized in that: The positive photoresist composition is the positive photoresist composition according to any one of claims 1 to 7.

9. The method for forming a photoresist pattern according to claim 8, characterized in that: The following steps are involved: (1) providing a substrate, wherein the surface of the substrate comprises one or more layers to be patterned, and adding the positive photoresist composition according to any one of claims 1 to 7 onto the layers to be patterned to form a positive photoresist composition layer; (2) pre-baking the positive photoresist composition layer; (3) exposing the positive photoresist composition layer to actinic radiation using a photolithography device; (4) placing the exposed positive photoresist composition layer in a developer for development to obtain a photoresist pattern; (5) The obtained photoresist pattern is hardened by baking.

10. The method for forming a photoresist pattern according to claim 9, characterized in that: The pre-baking temperature in step (2) is in the range of 80-120°C, and the baking time is 60s-180s. In step (3), a single wavelength light source or a mixed wavelength light source with a wavelength in the range of 350-450nm is used for actinic radiation exposure. In step (4), a tetramethylammonium hydroxide aqueous solution with a temperature of 23-25°C and a concentration in the range of 1.83%-3.5% is used for development for 60s-200s. In step (5), the hardening film baking temperature is in the range of 90-140°C, and the baking time is 2-10 minutes.

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