An antireflective coating composition and a method of making the same

Abstract

The application relates to the field of photoetching technology and discloses an antireflection coating composition and a preparation method thereof. The antireflection coating composition comprises the following components by weight: 15-20 parts of acrylic resin, 3-5 parts of a catalyst, 5-8 parts of a crosslinking agent and 400-700 parts of a solvent; and the catalyst comprises sodium p-toluenesulfonate and a chlorobenzene boronic acid compound. The technical scheme solves the problem of insufficient antireflection performance of the coating composition in the related art.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photoetching technology, in particular, to an antireflection coating composition and a preparation method thereof. BACKGROUND

[0002] In the photoetching process, light needs to penetrate the photoresist layer and achieve accurate exposure on the wafer substrate surface. However, the interface between the photoresist and air and the interface between the photoresist and the substrate are prone to interface reflection due to the difference in refractive index. To solve the above reflection interference problem, the industry generally introduces an antireflection coating layer between the photoresist layer and the substrate.

[0003] The antireflection coating layer is mainly composed of a resin matrix, a crosslinking agent and a catalyst. The catalytic activity of the catalyst directly determines the crosslinking reaction efficiency, reaction uniformity and the microstructure of the finally formed film of the resin and the crosslinking agent. The current catalytic system generally has the problem of difficult control of catalytic activity. Too fast or too slow catalytic activity can seriously damage the optical uniformity of the coating layer, forming a local abnormal refractive index area, and seriously affecting the antireflection performance of the coating layer.

[0004] If the antireflection performance of the coating layer is insufficient, the coating cannot absorb or offset the reflected light at the interface between the substrate and the photoresist, resulting in uneven light intensity distribution in the exposure area, which causes the photoetching pattern defect rate to soar and the yield to decrease. Not only the performance and reliability of the chip are reduced, but also the production resources are wasted.

[0005] Therefore, it is necessary to develop a coating composition with better antireflection performance. SUMMARY

[0006] The present application provides an antireflection coating composition and a preparation method thereof, which solves the problem of insufficient antireflection performance of the coating composition in the related art.

[0007] The technical scheme of the present application is as follows: The present application provides an antireflection coating composition, which comprises the following components by weight: 15-20 parts of acrylic resin, 3-5 parts of catalyst, 5-8 parts of crosslinking agent and 400-700 parts of solvent; the catalyst comprises sodium p-toluenesulfonate and a chlorobenzene boronic acid compound.

[0008] As a further technical scheme, the chlorobenzene boronic acid compound comprises one or more of 2,6-dichlorobenzene boronic acid, 3-chlorobenzene boronic acid and 3,4,5-trichlorobenzene boronic acid, preferably 2,6-dichlorobenzene boronic acid.

[0009] The chlorobenzene boronic acid compound in the anti-reflective coating composition of the present application is one of the catalysts, and the introduced chlorine atom in the chlorobenzene boronic acid compound reduces the acid strength of the benzene boronic acid compound, which not only avoids the local excessive crosslinking caused by the excessive activity of the chlorine-free benzene boronic acid, but also overcomes the defect of incomplete crosslinking of the single weakly active catalyst. The chlorobenzene boronic acid compound is preferably 2,6-dichlorobenzene boronic acid, and the moderate chlorine content of 2,6-dichlorobenzene boronic acid helps to promote the formation of a dense coating structure without pores and stress concentration, thereby improving the anti-reflective performance of the coating.

[0010] As a further technical solution, the mass ratio of the sodium p-toluenesulfonate to the chlorobenzene boronic acid compound is 5:1~2.

[0011] As a further technical solution, the crosslinking agent is composed of urea-formaldehyde resin and melamine modified urea-formaldehyde resin with a mass ratio of 1:1.3~1.5.

[0012] The crosslinking agent in the anti-reflective coating composition of the present application is composed of urea-formaldehyde resin and melamine modified urea-formaldehyde resin. The urea-formaldehyde resin has a relatively fast crosslinking reaction rate and a small curing shrinkage, and the melamine modified urea-formaldehyde resin has a higher crosslinking bond density and a slightly larger shrinkage. The two components are complementary in the shrinkage process in terms of reaction rate and shrinkage stress, which can avoid the film thickness depression or protrusion caused by the difference in local shrinkage rate, and promote the film thickness uniformity of the coating.

[0013] As a further technical solution, the solid content of the melamine modified urea-formaldehyde resin is 63wt%~65wt%, preferably 63wt%.

[0014] As a further technical solution, the urea-formaldehyde resin is composed of a first urea-formaldehyde resin and a second urea-formaldehyde resin, and the solid contents of the first urea-formaldehyde resin and the second urea-formaldehyde resin are different.

[0015] As a further technical solution, the solid content of the first urea-formaldehyde resin is 50wt%, the solid content of the second urea-formaldehyde resin is 65wt%, and the mass ratio of the first urea-formaldehyde resin to the second urea-formaldehyde resin is 1:1~1.2.

[0016] The urea-formaldehyde resin in the anti-reflective coating composition of the present application is composed of a first urea-formaldehyde resin and a second urea-formaldehyde resin with different solid contents. The solid content of the first urea-formaldehyde resin is 50wt%, which is relatively low and has a high reaction activity, so that the crosslinking reaction can be quickly started after contacting with the catalyst. The solid content of the second urea-formaldehyde resin is 65wt%, which is relatively high and has a high molecular chain density and a slightly lower reaction activity. The two components are complementary in combination with the catalyst, which can promote the formation of a more uniform crosslinking structure and improve the film thickness uniformity of the coating.

[0017] As a further technical solution, the raw material of the acrylic resin comprises glycidyl acrylate and 9-anthracene carboxylic acid.

[0018] As a further technical solution, the solvent comprises one or more of methyl ether, cyclopentanone, and diethylene glycol monobutyl ether, preferably diethylene glycol monobutyl ether.

[0019] The present application also provides a preparation method of the anti-reflection coating composition, for preparing the anti-reflection coating composition, comprising the following steps: adding the acrylic resin, the catalyst, and the cross-linking agent into the solvent, mixing, and obtaining the anti-reflection coating composition.

[0020] As a further technical solution, the mixing temperature is 80-100℃, for example, it can be 80℃, 85℃, 90℃, 95℃, or 100℃, preferably 90℃, and the mixing time is 3-5h, for example, it can be 3h, 3.5h, 4h, 4.5h, or 5h, preferably 4h.

[0021] The working principle and beneficial effects of the present application are as follows:

[0022] In the coating composition of the present application, sodium p-toluenesulfonate and chlorobenzene boronic acid compounds are used as catalysts to form a uniform and dense coating layer by regulating the catalytic activity, thereby improving the anti-reflection performance of the coating layer. In the prior art, the activity of the catalyst is uncontrollable. In the present application, sodium p-toluenesulfonate and chlorobenzene boronic acid compounds are used as catalysts. The catalytic activity of sodium p-toluenesulfonate is relatively high, and the addition of chlorobenzene boronic acid compounds can further buffer the catalytic strength of sodium p-toluenesulfonate. The use of the two substances can not only ensure the reaction efficiency of the resin and the cross-linking agent, but also inhibit the local reaction rate from being too fast, so that the cross-linking reaction proceeds uniformly within a controllable range, promotes the formation of a uniform coating layer, and improves the anti-reflection performance of the coating layer. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] In the following examples and comparative examples:

[0025] The first urea-formaldehyde resin has a solid content of 50wt%;

[0026] The second urea-formaldehyde resin has a solid content of 65wt%;

[0027] The melamine-modified urea-formaldehyde resin has a solid content of 63wt%;

[0028] The acrylic resin is prepared from glycidyl acrylate and 9-anthracene carboxylic acid in a molar ratio of 2:1 by a conventional method, and has a weight average molecular weight of 12000.

[0029] Example 1

[0030] A preparation method of an anti-reflection coating composition, comprising the following steps: adding 15 parts of acrylic resin, 3 parts of catalyst, 5 parts of crosslinking agent into 400 parts of diethylene glycol monobutyl ether, mixing at 90℃ for 4h to obtain the anti-reflection coating composition;

[0031] The catalyst is composed of sodium p-toluenesulfonate and 3-chlorobenzene boronic acid in a mass ratio of 5:1.

[0032] The crosslinking agent is a first urea-formaldehyde resin.

[0033] Example 2

[0034] A preparation method of an anti-reflection coating composition, comprising the following steps: adding 18 parts of acrylic resin, 4 parts of catalyst, 6 parts of crosslinking agent into 550 parts of diethylene glycol monobutyl ether, mixing at 90℃ for 4h to obtain the anti-reflection coating composition;

[0035] The catalyst is composed of sodium p-toluenesulfonate and 3-chlorobenzene boronic acid in a mass ratio of 5:1.

[0036] The crosslinking agent is a first urea-formaldehyde resin.

[0037] Example 3

[0038] A preparation method of an anti-reflection coating composition, comprising the following steps: adding 20 parts of acrylic resin, 5 parts of catalyst, 8 parts of crosslinking agent into 700 parts of diethylene glycol monobutyl ether, mixing at 90℃ for 4h to obtain the anti-reflection coating composition;

[0039] The catalyst is composed of sodium p-toluenesulfonate and 3-chlorobenzene boronic acid in a mass ratio of 5:1.

[0040] The crosslinking agent is a first urea-formaldehyde resin.

[0041] Example 4

[0042] Compared with Example 2, the difference of Example 4 is that the catalyst is composed of sodium p-toluenesulfonate and 3-chlorobenzene boronic acid in a mass ratio of 5:2.

[0043] Example 5

[0044] Compared with Example 4, the difference of Example 5 is that the 3-chlorobenzene boronic acid is replaced by an equal amount of 2,6-dichlorobenzene boronic acid.

[0045] Example 6

[0046] Example 6 differs from Example 4 in that the 3-chlorobenzenboronic acid is replaced with an equivalent amount of 3,4,5-trichlorobenzenboronic acid.

[0047] Example 7

[0048] Example 7 differs from Example 5 in that the crosslinking agent is melamine-modified urea-formaldehyde resin.

[0049] Example 8

[0050] Example 8 differs from Example 5 in that the crosslinking agent consists of a first urea-formaldehyde resin and melamine-modified urea-formaldehyde resin in a mass ratio of 1:1.3.

[0051] Example 9

[0052] Example 9 differs from Example 5 in that the crosslinking agent consists of a first urea-formaldehyde resin and melamine-modified urea-formaldehyde resin in a mass ratio of 1:1.5.

[0053] Example 10

[0054] Example 10 differs from Example 5 in that the crosslinking agent consists of a second urea-formaldehyde resin and melamine-modified urea-formaldehyde resin in a mass ratio of 1:1.5.

[0055] Example 11

[0056] Example 11 differs from Example 10 in that the second urea-formaldehyde resin is replaced with an equivalent amount of a first urea-formaldehyde resin and a second urea-formaldehyde resin in a mass ratio of 1:1.

[0057] Example 12

[0058] Example 12 differs from Example 10 in that the second urea-formaldehyde resin is replaced with an equivalent amount of a first urea-formaldehyde resin and a second urea-formaldehyde resin in a mass ratio of 1:1.2.

[0059] Comparative Example 1

[0060] Comparative Example 1 differs from Example 2 in that the catalyst is sodium p-toluenesulfonate.

[0061] Comparative Example 2

[0062] Comparative Example 2 differs from Example 2 in that the catalyst is 3-chlorobenzenboronic acid.

[0063] Comparative Example 3

[0064] Comparative Example 3 differs from Example 2 in that the 3-chlorobenzenboronic acid is replaced with an equivalent amount of benzenboronic acid.

[0065] Experimental Example 1

[0066] The anti-reflective coating prepared in Examples 1 to 6 and Comparative Examples 1 to 3 was spin-coated on a silicon wafer, and after baking at 200°C for 120 seconds to crosslink, a silicon wafer coated with the anti-reflective coating was obtained. The refractive index n of the anti-reflective coating was measured using an ellipsometer.

[0067] The test results are shown in Table 1.

[0068] Table 1. Refractive index test results of Examples 1 to 6 and Comparative Examples 1 to 3

[0069]

[0070] As shown in Table 1, when the catalyst is composed of sodium p-toluenesulfonate and chlorobenzene boronic acid compound, the anti-reflective performance of the coating can be improved.

[0071] Experimental Example 2

[0072] The anti-reflective coating prepared in Example 5 and Examples 7 to 12 was spin-coated on the surface of a silicon wafer, and after baking at 200°C for 120 seconds to crosslink, the film thickness uniformity of the coating surface was measured at 100 points.

[0073] Film thickness uniformity = (maximum film thickness - minimum film thickness) / (maximum film thickness + minimum film thickness) x 100%.

[0074] The test results are shown in Table 2.

[0075] Table 2. Film thickness uniformity test results of Example 5 and Examples 7 to 12

[0076]

[0077] As shown in Table 2, when the crosslinking agent is composed of urea-formaldehyde resin and melamine-modified urea-formaldehyde resin, and the urea-formaldehyde resin is composed of first urea-formaldehyde resin and second urea-formaldehyde resin with different solid contents, the film thickness uniformity of the coating obtained is better.

[0078] The above merely provides the preferred embodiments of the present application, but is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An anti-reflective coating composition, characterized in that, The raw materials include the following components by weight: 15-20 parts acrylic resin, 3-5 parts catalyst, 5-8 parts crosslinking agent, and 400-700 parts solvent; the catalyst includes sodium p-toluenesulfonate and chlorophenylboronic acid compounds. The chlorophenylboronic acid compound includes one or more of 2,6-dichlorophenylboronic acid, 3-chlorophenylboronic acid, and 3,4,5-trichlorophenylboronic acid; The crosslinking agent is composed of urea-formaldehyde resin and melamine-modified urea-formaldehyde resin in a mass ratio of 1:1.3~1.5; The raw materials for the acrylic resin include glycidyl acrylate and 9-anthracarboxylic acid.

2. The antireflective coating composition according to claim 1, characterized in that, The mass ratio of sodium p-toluenesulfonate to the chlorophenylboronic acid compound is 5:1~2.

3. The antireflective coating composition according to claim 1, characterized in that, The solid content of the melamine-modified urea-formaldehyde resin is 63wt%~65wt%.

4. The antireflective coating composition according to claim 1, characterized in that, The urea-formaldehyde resin is composed of a first urea-formaldehyde resin and a second urea-formaldehyde resin, and the first urea-formaldehyde resin and the second urea-formaldehyde resin have different solid contents.

5. The antireflective coating composition according to claim 4, characterized in that, The first urea-formaldehyde resin has a solid content of 50 wt%, the second urea-formaldehyde resin has a solid content of 65 wt%, and the mass ratio of the first urea-formaldehyde resin to the second urea-formaldehyde resin is 1:1 to 1.

2.

6. The antireflective coating composition according to claim 1, characterized in that, The solvent includes one or more of dimethyl ether, cyclopentanone, and diethylene glycol monobutyl ether.

7. A method for preparing an antireflective coating composition, used to prepare the antireflective coating composition according to any one of claims 1 to 6, characterized in that, The process includes the following steps: adding acrylic resin, catalyst, and crosslinking agent to a solvent, mixing them, and obtaining an anti-reflective coating composition.

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