A chemically amplified negative UV photoresist, a preparation method and a use method thereof

Abstract

The application relates to the technical field of photoresists, and discloses a chemical amplification type negative UV photoresist, which comprises the following components in percentage by mass: PHS resin 10-20%; photoacid generator 0.3-1.5%; crosslinking agent 0.2-2.0%; leveling agent 0.01-0.05%; and solvent in the rest amount. In the application, the addition amount of the crosslinking agent is 0.55-0.75%, the standing wave effect is improved, the standing wave effect is most obviously improved when the addition amount of the crosslinking agent is 0.5%, and the effect is the best. The addition amount of the crosslinking agent in the formula of the application can ensure the film strength of the pattern, reduce the crosslinking degree, and further reduce the difference between the side of the photoresist soaked in the developing solution caused by overexposure and underexposure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photoresist technology, in particular to a chemically amplified negative UV photoresist, a preparation method and a use method thereof. BACKGROUND

[0002] When the photoresist is exposed to light, the light is transmitted through the photoresist and irradiated on the silicon (Si) substrate. At the interface between the photoresist and the substrate, the light is reflected. The reflected light and the incident light form interference, which makes the distribution of light intensity along the depth direction of the glue uneven, forming a standing wave effect.

[0003] The standing wave effect has a more significant impact on deep ultraviolet photoresist, because many silicon wafer surfaces (such as oxide layers, silicon nitride, and polycrystalline silicon) reflect more strongly at shorter deep ultraviolet wavelengths. After exposure, the side of the photoresist is formed by overexposure and underexposure.

[0004] The standing wave essentially reduces the resolution of photoresist imaging. The standing wave effect destroys the verticality of the photoresist pattern sidewall, and also leads to instability of photoresist line width measurement,

[0005] The methods to eliminate the standing wave are: adjusting the PAB or PEB temperature, increasing the UV absorption of the resin and controlling the acid diffusion. As described in document 1 (Standing wave reduction of positive and negative I-line resists, 2005, Proc. of SPIE), the method of adjusting the temperature of PAB and PEB is used to eliminate the standing wave. Document 2 (Formulation and Molding of Dyed Positive I-line Resist for Control of the Reflective Notching and CD Variation, 1995, Proc. of SPIE) describes the effect of Dye UV absorption on the standing wave. US Patent US7632630B2 eliminates the standing wave by increasing the UV absorption of the resin. Chinese Patent CN1965265B controls the acid diffusion by increasing the high-boiling-point solvent to eliminate the influence of the standing wave. However, the above-mentioned documents or patents cannot achieve satisfactory performance.

[0006] Therefore, we propose a chemically amplified negative UV photoresist, a preparation method and a use method thereof. SUMMARY

[0007] In view of the above-mentioned deficiencies in the prior art, the present application provides a chemically amplified negative UV photoresist, a preparation method and a use method thereof.

[0008] The application provides the following technical scheme: a kind of chemical amplification type negative UV photoresist, the photoresist includes the following components by mass percentage:

[0009] PHS resin 10-20%;

[0010] Photoacid generator 0.3-1.5%;

[0011] Crosslinking agent 0.2-2.0%;

[0012] Leveling agent 0.01-0.05%;

[0013] Solvent the rest.

[0014] Preferably, the crosslinking agent is one or both of tetramethoxymethyl glycoluril and hexamethoxymethyl melamine.

[0015] Preferably, the molecular weight of the PHS resin is 6000-30000.

[0016] Preferably, the photoacid generator includes N-hydroxynaphthalimide triflate (PAG 1), (4,8-dihydroxy-1-naphthyl)dimethylsulfonium triflate (PAG 2), (4,7-dihydroxy-1-naphthyl)dimethylsulfonium triflate (PAG 3), (4-methoxynaphthyl)diphenylsulfonium triflate (PAG 4), (4-phenylthiophenyl)diphenylsulfonium triflate (PAG 5), 2-(benzo[d][1,3]dioxol-5-yl)-4,6-bis(trichloromethyl)-1,3,5-triazine (PAG 6), 2-(2,4-dimethoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine (PAG 7), 2-[4-(4-methoxyphenyl)phenyl]-4,6-bis(trichloromethyl)-1,3,5-triazine (PAG 8), as follows:

[0017]

[0018] Preferably, the leveling agent is one or both of 3M fluorocarbon surfactant FC-4430 and Troysol S366.

[0019] Preferably, the solvent is one or both of propylene glycol methyl ether acetate, ethyl lactate, and propylene glycol methyl ether.

[0020] A preparation method of a chemical amplification type negative UV photoresist includes the following steps: mixing PHS resin, photoacid generator, crosslinking agent, leveling agent, and solvent, stirring and dissolving, and then filtering through a microporous filter with a pore size of 0.45 / 0.22 μm to obtain a photoresist.

[0021] The application discloses a method for using a chemical amplification type negative UV photoresist, and is characterized by comprising the following steps: spin coating the photoresist on a silicon wafer, and sequentially performing pre-baking, exposure, post-baking and development to obtain a photoetching pattern.

[0022] Preferably, the pre-baking temperature is 80-110 DEG C, the pre-baking time is 40-80s; the exposure energy is 100-400msec; the post-baking temperature is 80-110 DEG C, the post-baking time is 40-80s; the developing solution is a 2.38% mass fraction of tetramethylammonium hydroxide aqueous solution, and the developing time is 60s.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] In the application, the addition amount of the crosslinking agent is 0.55-0.75%, the standing wave effect is improved, and the addition amount of the crosslinking agent is 0.5%, the standing wave effect is most obviously improved, and the effect is best.

[0025] In the formula of the application, the addition amount of the crosslinking agent ensures the film strength of the obtained pattern, reduces the crosslinking degree, and further reduces the difference between the side of the photoresist caused by overexposure and underexposure. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a slice diagram of a photoetching pattern of the application example 1;

[0027] Figure 2 It is a slice diagram of a photoetching pattern of the application example 2;

[0028] Figure 3 It is a slice diagram of a photoetching pattern of the application example 3;

[0029] Figure 4 It is a slice diagram of a photoetching pattern of the application example 4;

[0030] Figure 5 It is a slice diagram of a photoetching pattern of the application example 5. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application, and in order to keep the following description of the embodiments of the present application clear and brief, the present application omits the detailed description of known functions and known components to avoid unnecessary confusion of the concept of the present application.

[0032] A kind of chemical amplification type negative UV photoresist, the photoresist includes the following components by mass percentage: 10-20% PHS resin;0.3-1.5% photoacid generator;0.2-2.0% crosslinking agent;0.01-0.05% leveling agent;the rest is solvent.

[0033] Example 1

[0034] A kind of chemical amplification type negative UV photoresist, including the following components by mass fraction: 15% PHS resin, 0.75% PAG 3, 0.525% tetramethoxymethyl glycoluril, 0.02% 3M fluorocarbon surfactant FC-4430, 80.705% propylene glycol methyl ether acetate, 3.0% ethyl lactate.

[0035] The preparation method of the above-mentioned photoresist specifically includes the following steps: weighing the above-mentioned components respectively, stirring to achieve complete dissolution, then filtering through a polypropylene microporous filter with a pore size of 0.45 / 0.22 μm to obtain the photoresist.

[0036] The use method of the above-mentioned photoresist specifically includes the following steps: first, spin coating the obtained photoresist on a 4-inch silicon wafer, the coating film thickness of the photoresist is 1 μm, second, pre-baking at 90°C for 60 s, then exposing in an exposure machine with an exposure energy of 200 mJ / cm2, then post-baking at 90°C for 60 s, finally developing in a developer with a mass fraction of 2.38% TMAH aqueous solution for 60 s to obtain a photoresist pattern.

[0037] The obtained photoresist pattern is subjected to photoetching, as shown in Figure 1 , and the specific results are shown in Table 1.

[0038] Example 2

[0039] A kind of chemical amplification type negative UV photoresist, including the following components by mass fraction: 15.0% PHS resin, 0.55% PAG 2, 0.5% hexamethoxymethyl melamine, 0.03% Troysol S366, 83.92% ethyl lactate.

[0040] The preparation method of the above-mentioned photoresist is the same as that of Example 1.

[0041] The use method of the above-mentioned photoresist is the same as that of Example 1.

[0042] The obtained photoresist pattern is subjected to photoetching, as shown in Figure 2 , and the specific results are shown in Table 1.

[0043] Example 3

[0044] A kind of chemical amplification type negative UV photoresist, including the following mass parts of composition: 15.0% PHS resin, 0.75% PAG 3, 0.75% tetramethoxymethyl glycoluril, 0.02% 3M fluorocarbon surfactant FC-4430, 79.25% propylene glycol methyl ether acetate, 4.23% ethyl lactate.

[0045] The preparation method of the above-mentioned photoresist is the same as that of example 1.

[0046] The use method of the above-mentioned photoresist is the same as that of example 1.

[0047] The obtained photoetching pattern is photoetched, as shown in Figure 3 , and the specific results are shown in Table 1.

[0048] Example 4

[0049] A kind of chemical amplification type negative UV photoresist, including the following mass parts of composition: 15.0% PHS resin, 0.75% PAG 3, 1.35% tetramethoxymethyl glycoluril, 0.02% 3M fluorocarbon surfactant FC-4430, 75.28% propylene glycol methyl ether acetate, 7.60% ethyl lactate.

[0050] The preparation method of the above-mentioned photoresist is the same as that of example 1.

[0051] The use method of the above-mentioned photoresist is the same as that of example 1.

[0052] The obtained photoetching pattern is photoetched, as shown in Figure 4 , and the specific results are shown in Table 1.

[0053] Example 5

[0054] A kind of chemical amplification type negative UV photoresist, including the following mass parts of composition: 15.0% PHS resin, 0.75% PAG 3, 1.95% tetramethoxymethyl glycoluril, 0.02% 3M fluorocarbon surfactant FC-4430, 71.28% propylene glycol methyl ether acetate, 11% ethyl lactate.

[0055] The preparation method of the above-mentioned photoresist is the same as that of example 1.

[0056] The use method of the above-mentioned photoresist is the same as that of example 1.

[0057] The obtained photoetching pattern is photoetched, as shown in Figure 5 , and the specific results are shown in Table 1.

[0058] The photoetching standing wave degree results of the photoresist of the above-mentioned examples 1-5 are as follows Table 1:

[0059] Table 1: Standing wave degree results of Examples 1-5

[0060] Group Example 1 Example 2 Example 3 Example 4 Example 5 Degree of standing wave Not obvious Not obvious Obvious Very obvious Very obvious

[0061] As Figures 1-5 As shown in Table 1, in Example 1, the mass percentage of the crosslinking agent tetramethoxymethyl glycoluril is 0.525%, and the result is that the standing wave degree is not obvious; in Example 2, the mass percentage of the crosslinking agent hexamethoxymethyl melamine is 0.5%, and the result is that the standing wave degree is not obvious; in Example 3, the mass percentage of the crosslinking agent tetramethoxymethyl glycoluril is 0.75%, and the result is that the standing wave degree is obvious; in Example 4, the mass percentage of the crosslinking agent tetramethoxymethyl glycoluril is 1.35%, and the result is that the standing wave degree is very obvious; in Example 5, the mass percentage of the crosslinking agent tetramethoxymethyl glycoluril is 1.95%, and the result is that the standing wave degree is very obvious.

[0062] As shown in Examples 1 and 3-5, with the increase of the mass percentage of the crosslinking agent tetramethoxymethyl glycoluril, the standing wave effect is more obvious. That is, the standing wave effect is improved when the mass percentage of the crosslinking agent is between 0.5-0.75%, and the standing wave effect is most obviously improved when the mass percentage of the crosslinking agent is 0.5%.

[0063] As shown in Examples 1 and 2, in Example 1, the mass percentage of the crosslinking agent tetramethoxymethyl glycoluril is 0.525%; in Example 2, the mass percentage of the crosslinking agent hexamethoxymethyl melamine is 0.5%, and in the case of the same or similar mass percentage, changing the type of the crosslinking agent has little effect on improving the standing wave effect.

[0064] Therefore, the appropriate amount of the crosslinking agent can eliminate the standing wave and ensure the film strength of the pattern.

[0065] The photoresist according to the application is suitable for preparing an integrated circuit PAD process or a high-energy implantation process.

[0066] The above examples are only exemplary embodiments of the application and are not used to limit the application, and the protection scope of the application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the application within the spirit and protection scope of the application, and such modifications or equivalent replacements are also regarded as falling within the protection scope of the application.

Claims

1. A chemically amplified negative UV photoresist, characterized in that: The photoresist comprises the following components by weight percentage: PHS resin 10-20%; Photoacid-producing agent: 0.3-1.5%; Crosslinking agent 0.2-0.525%; Leveling agent 0.01-0.05%; Solvent balance; The crosslinking agent is one or both of tetramethoxymethylglycolurea and hexamethoxymethylmelamine; The photoinduced acid-producing agents include (4,8-dihydroxy-1-naphthyl)dimethylsulfonium trifluoromethanesulfonate (PAG 2), (4,7-dihydroxy-1-naphthyl)dimethylsulfonium trifluoromethanesulfonate (PAG 3), and (4-methoxynaphthyl)diphenylsulfonium trifluoromethanesulfonate (PAG 4), with the following structures: 、 、 ； The leveling agent is one or both of 3M fluorocarbon surfactant FC-4430 and Troysol S366.

2. The chemically amplified negative UV photoresist according to claim 1, characterized in that: The molecular weight of the PHS resin is 6000-30000.

3. The chemically amplified negative UV photoresist according to claim 1, characterized in that: The solvent is one or two of propylene glycol methyl ether acetate, ethyl lactate, and propylene glycol methyl ether.

4. A method for preparing a chemically amplified negative UV photoresist according to any one of claims 1 to 3, characterized in that: Includes the following steps: PHS resin, photoacid generator, crosslinking agent, leveling agent and solvent are mixed, stirred and dissolved, and then filtered through a microporous membrane filter with a pore size of 0.45 / 0.22μm to obtain photoresist.

5. A method of using a chemically amplified negative UV photoresist according to any one of claims 1 to 3, characterized in that: Includes the following steps: The photoresist is spin-coated onto a silicon wafer, and then sequentially subjected to pre-baking, exposure, post-baking, and development to obtain a photolithographic pattern. The pre-baking temperature is 80-110℃, and the pre-baking time is 40-80s. The exposure energy is 100-400ms. The post-baking temperature is 80-110℃, and the post-baking time is 40-80s. The developing solution is a 2.38% tetramethylammonium hydroxide aqueous solution, and the developing time is 60s.

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