Positive and negative reversal photoresist composition and application thereof

Abstract

The invention belongs to the field of fine pattern processing, and particularly relates to a positive and negative reversal photoresist composition and application thereof. The positive and negative reversal photoresist composition comprises PDHF with the mass fraction of 1 wt%-10 wt%, a photoacid generator with the mass being 10 wt%-40 wt% of the mass of the PDHF, and a solvent. The average molecular weight of the PDHF is 100,000-300,000, and the solvent is one or more of ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, tetrahydrofuran, cyclohexanone, methylbenzene, dimethyl sulfoxide, ethyl lactate, n-heptane, butyl acetate and gamma-butyrolactone. The positive and negative reversal photoresist composition is based on the principles of cationic crosslinking and acid catalysis hydrolysis, after the composition is used for exposure, positive photoresist and negative photoresist do not need to be baked, the patterning process is simplified, and the positive and negative reversal photoresist composition can be used for preparing positive patterns or negative patterns.

Description

Technical Field

[0001] The present application belongs to the field of fine pattern processing, and more specifically, relates to a positive-negative reversal photoresist composition and its application. Background Art

[0002] Positive-negative reversal photoresist is a special photoresist that can reverse the positive pattern to the negative pattern by changing the process conditions. It is mainly used in semiconductor manufacturing, MEMS (micro-electromechanical systems) and other fine pattern processing fields.

[0003] The core mechanism of existing positive-negative reversal photoresists, such as AZ5214E, involves photochemical and thermochemical reactions within the photoresist. The process includes exposure, reverse baking, full exposure, and development. Compared to conventional photolithography, this process is more complex due to the addition of reverse baking, requiring strict control of conditions such as the reverse baking temperature to prevent the resulting pattern from being affected.

[0004] The non-patent document "Synthesis and Characterization of Eco-Friendly Water-Processable Dual-Tone Photoresists Containing Photoreversible Coumarin Groups" discloses a 365 nm positive-negative reversible photoresist. The principle is that cyclic crosslinking occurs at 365 nm, and subsequent exposure at 248 nm triggers a reverse reaction. Exposure at 365 nm using a mask creates a negative resist, while full exposure without a mask is followed by exposure at 248 nm using a mask to create a positive resist. This requires two light sources and a relatively high photoresist dosage. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application has developed a novel positive-negative reversible photoresist composition based on cationic crosslinking and acid-catalyzed hydrolysis. This simple process requires no additional equipment and offers significant advantages in precision manufacturing fields such as semiconductors, MEMS, and photonic devices.

[0006] To achieve the above-mentioned objectives, the present application provides a positive-negative reversible photoresist composition, comprising PDHF with a mass fraction of 1wt% to 10wt%, a photoacid generator with a mass of 10wt% to 40wt% of the mass of the PDHF, and a solvent; the average molecular weight of the PDHF is 100,000 to 300,000, and the solvent is one or more of ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, tetrahydrofuran, cyclohexanone, toluene, dimethyl sulfoxide, ethyl lactate, n-heptane, butyl acetate, and γ-butyrolactone.

[0007] Preferably, the solvent is one or more of ethyl acetate, PGMEA, PGME, γ-butyrolactone, and ethyl lactate.

[0008] Preferably, the photoacid generator is one or more of an onium salt, o-nitrobenzyl sulfonate, imidosulfonate or N-hydroxyimidosulfonate.

[0009] As further preferred, the photoacid generator is o-nitrobenzyl sulfonate.

[0010] Preferably, the mass fraction of the PDHF is 3 wt % to 5 wt %, and the mass of the photoacid generator is 20 wt % to 30 wt % of the mass of the PDHF.

[0011] Another object of the present application is to provide a patterning application of the positive-negative reversal photoresist composition.

[0012] Preferably, the application comprises: coating the positive-negative reversal photoresist composition on a substrate, exposing the substrate, and developing the substrate for 20s to 60s to obtain a pattern.

[0013] As a further preferred embodiment, the exposure conditions are: using 20 mJ / cm 2 ~200mJ / cm 2 Exposure to a dose of The pattern is a negative pattern.

[0014] As a further preferred embodiment, the exposure conditions are: first, 20 mJ / cm 2 ~200mJ / cm 2 Full exposure was performed with a dose of 300 mJ / cm 2 ~2000mJ / cm 2 Exposure to a dose of The pattern is a positive pattern.

[0015] In general, the above technical solutions conceived by this application have the following technical advantages compared with the existing technologies: 1. The positive-negative reversible photoresist composition of this application is based on the principles of cationic crosslinking and acid-catalyzed hydrolysis. After exposure using this composition, neither the positive nor the negative photoresist requires baking, simplifying the patterning process. It can be used to prepare positive or negative patterns. 2. The positive-negative reversible photoresist composition of the present application has simple ingredients and requires only simple mixing for preparation; 3. The patterning process using the positive-negative reversible photoresist composition of the present application is simple and requires no additional equipment, which has significant advantages in the fields of precision manufacturing such as semiconductors, MEMS, and photonic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the negative pattern obtained in Example 1 of the present application; Figure 2 This is the positive pattern obtained in Example 1 of the present application. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0018] References throughout this specification to "one embodiment," "one embodiment," "an example," or similar language indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, appearances of the phrase "in one embodiment," "in one embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0019] To achieve the above-mentioned object, the present application provides a positive-negative reversible photoresist composition, comprising a mass fraction of 1 wt% to 10 wt% of poly(2,3-dihydrofuran) (PDHF), a photoacid generator whose mass is 10 wt% to 40 wt% of the mass of the PDHF, and a solvent; in some embodiments, the mass fraction of the PDHF is 3 wt% to 5 wt%; in other embodiments, the mass of the photoacid generator is 20 wt% to 30 wt% of the mass of the PDHF; in some embodiments, the photoacid generator is one or more of an onium salt, o-nitrobenzyl sulfonate, iminosulfonate, or N-hydroxyiminosulfonate, preferably o-nitrobenzyl sulfonate.

[0020] The average molecular weight of the PDHF is 100,000 to 300,000, and the solvent is one or more of ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, tetrahydrofuran, cyclohexanone, toluene, dimethyl sulfoxide, ethyl lactate, n-heptane, butyl acetate, and γ-butyrolactone; in some embodiments, the solvent is one or more of ethyl acetate, PGMEA, PGME, γ-butyrolactone, and ethyl lactate.

[0021] The above-mentioned positive-negative reversal photoresist composition can be used for patterning applications because the photoacid generator will generate acid under the irradiation of light. Under low exposure doses, the proton acid generated by the photoacid generator quickly triggers the cationic polymerization of the double bond structure of PDHF to partially crosslink the polymer in the exposed area, and the solubility of the exposed area changes. The unexposed area is soluble in the solvent, while the exposed area is insoluble in the solvent, forming a negative photoresist. Under low-dose full exposure without a mask, and then continued exposure with a mask, the acid will catalyze the hydrolysis of the remaining unreacted vinyl ether structure to degrade the partially cross-linked polymer in the continued exposure area, making it soluble in alcohol solvents, while the partially cross-linked polymer that is not further exposed is insoluble in alcohol solvents, forming a positive photoresist. The above-mentioned cationic crosslinking and acid-catalyzed hydrolysis do not require baking and can occur at room temperature, so that the positive-negative reversal photoresist composition of the present application can be used to prepare positive or negative photoresists without baking.

[0022] The patterning method of the positive-negative reversible photoresist composition of this embodiment is as follows: (1) Spin coating the photoresist composition on a surface of a substrate such as a silicon wafer to obtain a photoresist film; in some embodiments, the spin coating can be performed at a speed of 2000 rpm to 4000 rpm for 30 seconds; (2) When a negative pattern is required, use 20 mJ / cm with a mask. 2 ~ 200mJ / cm 2 The negative pattern is obtained by exposure with a dose of 100 nm and then developing for 20s to 60s. (3) If a positive pattern is required, first use 20mJ / cm 2 ~200mJ / cm 2 Full exposure was performed with a dose of 300 mJ / cm 2 ~2000mJ / cm 2 The photoresist composition in the continuously exposed area is exposed to light for a dose of 100 nm. After exposure, the polymer in the continuously exposed area undergoes partial crosslinking and then acid-catalyzed hydrolysis. The acid-catalyzed hydrolysis degrades the partially crosslinked polymer in the exposed area and increases its polarity, making it soluble in the solvent. The unexposed area is insoluble in the solvent. The positive pattern is then developed for 20 to 60 seconds.

[0023] Example 1 S1. Preparation of Photoresist Composition S11. Preparation of Polymer PDHF G3 catalyst (0.003 g, 0.0034 mmol) and 2,3-dihydrofuran (3 g, 42.8 mmol) were added to the flask and stirred at room temperature for 1 minute before being allowed to stand for 10 minutes. The mixture became rubbery. 80 mL of dichloromethane was added and allowed to stand overnight to completely dissolve the mixture. The mixture was then filtered through a 0.22 μm filter and added dropwise to ethanol to precipitate the resulting polymer, PDHF. The average molecular weight was approximately 170,000.

[0024]

[0025] S12. Preparation of Photoresist Composition The polymer PDHF is mixed with other ingredients to obtain a positive-negative reversible photoresist composition. The positive-negative reversible photoresist composition of this embodiment includes ethyl acetate, 1.5 wt% of poly(2,3-dihydrofuran) (PDHF) based on ethyl acetate, and 30 wt% of PDHF based on 4,5-dimethoxy-2-nitrobenzyl toluenesulfonate (i.e., 0.45% of ethyl acetate). S2. Preparation of Negative Patterns The photoresist composition was spin-coated onto a silicon wafer, baked at 70 °C for 30 s, and exposed using a 365 nm photolithography machine and a patterned mask. The exposure dose was 35 mJ / cm 2 When the film is developed in ethyl acetate for 30 s, a negative pattern is obtained, such as Figure 1 shown.

[0026] S3. Preparation of positive patterns The photoresist composition was spin-coated onto a silicon wafer, baked at 70 °C for 30 s, and exposed using a 365 nm photolithography machine and a patterned mask. Full exposure: 35 mJ / cm 2 After that, continue to expose 1300 mJ / cm 2 , developed in ethanol for 30 s to obtain a positive pattern, such as Figure 2 shown.

[0027] It can be seen that at the resolution shown in the figure, whether it is a positive pattern or a negative pattern, the lines are smooth and the structure is clear, which can fully meet the micron level and patterning requirements.

[0028] Using the same photoresist composition, the development parameters in steps S2-S3 are adjusted. For example, the exposure dose in step S2 and the full exposure dose in step S3 are 20 mJ / cm 2 ~200mJ / cm 2 or the exposure dose in step S3 is adjusted to 20 mJ / cm 2 ~200mJ / cm 2Alternatively, the development time in steps S2-S3 is adjusted between 20s and 60s, and the quality and clarity of the prepared positive and negative patterns are similar to those of the conventional methods. Figure 1 、 Figure 2 similar.

[0029] Examples 2-7 The photoresist compositions of Examples 2-7 were prepared in the same manner as in step S12 of Example 1, with the ingredients adjusted according to Table 1.

[0030] Table 1 Compositions of the positive-negative reversal photoresist compositions of Examples 2-7

[0031] Using the same positive-negative reversal photoresist composition as in Example 2-7 and the same template as in Example 1, the negative pattern and the positive pattern were prepared again according to steps S2 and S3 of Example 1. The quality and clarity of the prepared patterns were comparable to those of the Figure 1 、 Figure 2 Similarly, there is no significant impact.

[0032] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A positive-negative reversible photoresist composition, characterized in that: The invention comprises PDHF with a mass fraction of 1wt% to 10wt%, a photoacid generator with a mass of 10wt% to 40wt% of the mass of the PDHF, and a solvent; the average molecular weight of the PDHF is 100,000 to 300,000, and the solvent is one or more of ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, tetrahydrofuran, cyclohexanone, toluene, dimethyl sulfoxide, ethyl lactate, n-heptane, butyl acetate, and γ-butyrolactone.

2. The positive-negative reversible photoresist composition according to claim 1, wherein The solvent is one or more of ethyl acetate, PGMEA, PGME, γ-butyrolactone, and ethyl lactate.

3. The positive-negative reversible photoresist composition according to claim 1, wherein The photoacid generator is one or more of onium salt, o-nitrobenzyl sulfonate, iminosulfonate or N-hydroxyiminosulfonate.

4. The positive-negative reversible photoresist composition according to claim 3, wherein: The photoacid generator is o-nitrobenzyl sulfonate.

5. The positive-negative reversible photoresist composition according to claim 1, wherein The mass fraction of the PDHF is 3 wt % to 5 wt %, and the mass of the photoacid generator is 20 wt % to 30 wt % of the mass of the PDHF.

6. Patterning application of the positive-negative reversible photoresist composition according to any one of claims 1 to 5.

7. The patterned application according to claim 6, wherein: include: The positive-negative reversible photoresist composition is coated on a substrate for exposure, and developed for 20s to 60s to obtain a pattern.

8. The patterned application according to claim 7, wherein: The exposure conditions are: 20 mJ / cm 2 ~200mJ / cm 2 Exposure to a dose of The pattern is a negative pattern.

9. The patterned application according to claim 7, wherein: The exposure conditions are: first use 20mJ / cm 2 ~200mJ / cm 2 Full exposure was performed with a dose of 300 mJ / cm 2 ~2000mJ / cm 2 Exposure to a dose of The pattern is a positive pattern.

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