A positive and negative tone reversal photoresist composition and use thereof

Abstract

The application belongs to the field of fine pattern processing, and more particularly relates to a positive-negative reversal photoresist composition and application thereof. The positive-negative reversal photoresist composition comprises 1wt%-10wt% of PDHF, 10wt%-40wt% of a photoacid generator based on 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, toluene, dimethyl sulfoxide, ethyl lactate, n-heptane, butyl acetate and gamma-butyrolactone. The positive-negative reversal photoresist composition is based on the principle of cationic crosslinking and acid-catalyzed hydrolysis, and after exposure using the composition, neither the positive resist nor the negative resist needs to be baked, thus simplifying the patterning process and enabling the preparation of positive patterns or negative patterns.

Description

Technical Field

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

[0002] Reversible photoresist is a special type of photoresist that can reverse positive patterns to negative patterns by changing process conditions. It is mainly used in semiconductor manufacturing, MEMS (microelectromechanical systems), and other fields of fine pattern processing.

[0003] Existing positive-negative reversal photoresists, such as AZ5214E, involve photochemical and thermochemical reactions of the photoresist through their core mechanism. The process includes exposure, reversal baking, full exposure, and development. Compared to conventional photolithography, this process is more complex due to the addition of reversal baking. Therefore, it is necessary to strictly control conditions such as the reversal baking temperature, otherwise the resulting pattern will be 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 reversal photoresist. The principle is that cyclization crosslinking occurs at 365 nm, followed by a reverse reaction upon exposure at 248 nm. The negative photoresist is obtained through 365 nm exposure with a mask, and the positive photoresist is obtained through full exposure without a mask followed by 248 nm exposure with another mask. This process requires two light sources and a relatively large amount of photoresist. Summary of the Invention

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

[0006] To achieve the above objectives, this application provides a photoresist composition for positive and negative reversal, comprising 1 wt% to 10 wt% PDHF, 10 wt% to 40 wt% photoacid-generating agent by mass of the PDHF, and a solvent; wherein the PDHF has an average molecular weight of 100,000 to 300,000, and the solvent is ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, tetrahydrofuran, cyclohexanone, toluene, dimethyl sulfoxide, ethyl lactate, n-heptane, butyl acetate, γ-ray dimethyl ether (DME), etc. One or more of butyrolactones.

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

[0008] Preferably, the photoacid-producing agent is one or more of onium salt, o-nitrobenzyl sulfonate, iminosulfonate, or N-hydroxyiminosulfonate.

[0009] As a further preferred embodiment, the photoacid-generating agent is o-nitrobenzyl sulfonate.

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

[0011] Another object of this application is to provide patterned applications of the above-described positive and negative reversal photoresist composition.

[0012] Preferably, the application includes: coating the positive and negative reversal photoresist composition onto a substrate and exposing it, then developing it for 20s to 60s to obtain a pattern.

[0013] As a further preferred embodiment, the exposure conditions are: 20 mJ / cm² when a mask is used. 2 ~200mJ / cm 2 Expose at a dose; The pattern is a negative pattern.

[0014] As a further preferred embodiment, the exposure conditions are: first using 20 mJ / cm 2 ~200mJ / cm 2 Full exposure was performed using the appropriate dose, followed by exposure with a mask at 300 mJ / cm². 2 ~2000mJ / cm 2 Expose at a dose; The pattern is a positive pattern.

[0015] In summary, compared with the prior art, the technical solutions conceived in this application have the following main technical advantages: 1. The positive and negative reversal photoresist composition of this application is based on the principle of cationic crosslinking and acid-catalyzed hydrolysis. After exposure using the composition of this application, neither positive nor negative photoresist needs to be baked, which simplifies the patterning process and can be used to prepare positive or negative patterns. 2. The positive and negative reversal photoresist composition of this application has a simple composition, and its preparation only requires simple mixing; 3. The patterning process using the positive and negative reversal photoresist composition of this application is simple and requires no additional equipment, which has significant advantages in the field of precision manufacturing such as semiconductors, MEMS, and photonic devices. Attached Figure Description

[0016] Figure 1 The negative pattern obtained in Embodiment 1 of this application; Figure 2 This is the positive pattern obtained in Embodiment 1 of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0018] Throughout this specification, references to "an embodiment" are used; "an embodiment," "an example," or similar language indicate that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of this application. Therefore, the appearance of the phrase "in one embodiment;" throughout this specification, and similar language, may, but not necessarily, refer to the same embodiment.

[0019] To achieve the above objectives, this application provides a photoresist composition for positive and negative reversal, comprising 1 wt% to 10 wt% of poly(2,3-dihydrofuran) (PDHF), 10 wt% to 40 wt% of a photoacid-generating agent based on the mass of the PDHF, and a solvent; in some embodiments, the PDHF has a mass fraction of 3 wt% to 5 wt%; in other embodiments, the photoacid-generating agent has a mass fraction of 20 wt% to 30 wt%; in some embodiments, the photoacid-generating agent is one or more of onium salts, 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 ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, tetrahydrofuran, cyclohexanone, toluene, dimethyl sulfoxide, ethyl lactate, n-heptane, butyl acetate, γ-hydroxyethyl acetate, etc. One or more of butyrolactones; in some embodiments, the solvent is ethyl acetate, PGMEA, PGME, γ-hydroxybutyrolactone. One or more of butyrolactone and ethyl lactate.

[0021] The aforementioned positive / negative reversal photoresist composition can be used for patterned applications because the photoacid generator produces acid under light irradiation. At low exposure doses, the protic acid generated by the photoacid generator rapidly initiates cationic polymerization of the double bond structure of PDHF, causing partial crosslinking of the polymer in the exposed area. This alters the solubility of the exposed area; the unexposed area dissolves in the solvent, while the exposed area remains insoluble, forming a negative resist. Low-dose full exposure is performed without a mask, followed by continued exposure with a mask. The acid catalyzes the hydrolysis of the remaining unreacted vinyl ether structures, degrading the partially crosslinked polymer in the continued-exposed area, making it soluble in alcohol solvents. The partially crosslinked polymer in the unexposed area remains insoluble in alcohol solvents, forming a positive resist. Both the cationic crosslinking and acid-catalyzed hydrolysis occur at room temperature without baking, allowing the positive / negative reversal photoresist composition of this application to prepare positive or negative resists without baking.

[0022] The patterning method of the positive and negative reversal photoresist composition in this embodiment is as follows: (1) The photoresist composition is coated on the surface of a substrate such as a silicon wafer to obtain a photoresist film; In some embodiments, the photoresist film can be spin-coated for 30 s at a rotation speed of 2000 rpm to 4000 rpm. (2) When a negative pattern is required, use 20 mJ / cm² when a mask is used. 2 ~ 200mJ / cm 2 Expose to a certain dose, then develop for 20s~60s to obtain a negative pattern; (3) When a positive pattern is required, first use 20 mJ / cm 2 ~200mJ / cm 2 Full exposure was performed using the appropriate dose, followed by exposure with a mask at 300 mJ / cm². 2 ~2000mJ / cm 2 The photoresist composition in the exposed area is exposed to a certain dosage; after exposure, the polymer in the photoresist composition undergoes partial cross-linking and then acid-catalyzed hydrolysis. Acid-catalyzed hydrolysis causes the partially cross-linked polymer in the exposed area to degrade while increasing its polarity, making it soluble in the solvent, while the area not exposed is insoluble in the solvent; then development is performed for 20s~60s to obtain a positive pattern.

[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 a flask. The mixture was stirred at room temperature for 1 min and then allowed to stand for 10 min, resulting in a rubbery consistency. 80 mL of dichloromethane was added and allowed to stand overnight to allow the mixture to dissolve completely. After filtration through a 0.22-micron filter, the solution was added dropwise to ethanol to precipitate the polymer PDHF, which had an average molecular weight of approximately 170,000.

[0024]

[0025] S12. Preparation of photoresist composition The polymer PDHF was mixed with other components to obtain a positive and negative reversal photoresist composition. The positive and negative reversal photoresist composition of this embodiment includes ethyl acetate, 1.5 wt% of poly(2,3-dihydrofuran) (PDHF) of ethyl acetate, and 30 wt% of toluenesulfonic acid-4,5-dimethoxy-2-nitrobenzyl ester (i.e., 0.45% of ethyl acetate) of PDHF. S2. Preparation of negative patterns The photoresist composition was spin-coated onto a silicon wafer, baked at 70 °C for 30 s, and then exposed using a 365 nm lithography machine and a patterned photomask. The exposure dose was 35 mJ / cm². 2 At that time, a negative pattern was obtained by developing in ethyl acetate for 30 seconds, such as... Figure 1 As 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 then exposed using a 365 nm lithography machine and a patterned photomask. Full exposure yielded 35 mJ / cm². 2 Then, under the condition of having a mask, continue exposure at 1300 mJ / cm. 2 A positive pattern is obtained by developing in ethanol for 30 seconds, as shown below. Figure 2 As shown.

[0027] As can be seen, at the resolution shown in the figure, both positive and negative patterns have smooth lines and clear structures, which fully meet the requirements for micron-level patterns.

[0028] Using the same photoresist composition, adjust the development parameters in steps S2-S3. For example, the exposure dose in step S2 and the total exposure dose in step S3 are both 20 mJ / cm². 2 ~200mJ / cm 2 Adjust between these values, or maintain the exposure dose in step S3 at 300 mJ / cm². 2 ~2000mJ / cm 2Adjusting the time between steps S2 and S3, or adjusting the development time between 20s and 60s, will improve the quality and clarity of the prepared positive and negative patterns. Figure 1 , Figure 2 similar.

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

[0030] Table 1. Composition of the positive and negative reversal photoresist compositions in Examples 2-7

[0031] Using the same positive and negative reversal photoresist compositions as in Examples 2-7, and the same template as in Example 1, negative and positive patterns were re-prepared according to steps S2 and S3 of Example 1. The quality and clarity of the prepared patterns were the same as in Example 1. Figure 1 , Figure 2 Similarly, there was no significant impact.

[0032] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photoresist composition for positive and negative reversal, characterized in that, The product comprises 1 wt% to 10 wt% PDHF, 10 wt% to 40 wt% photoacid-producing agent by mass of the PDHF, and a solvent; the PDHF has an average molecular weight of 100,000 to 300,000, and the solvent is ethyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, tetrahydrofuran, cyclohexanone, toluene, ethyl lactate, butyl acetate, γ-ray diethyl ester, etc. One or more of butyrolactones; The photo-induced acid-producing agent is one or more of onium salts, o-nitrobenzyl sulfonate, iminosulfonate, or N-hydroxyiminosulfonate.

2. The photoresist composition for positive and negative reversal as described in claim 1, characterized in that, The solvent is ethyl acetate, PGMEA, PGME, γ-ray. One or more of butyrolactone and ethyl lactate.

3. The photoresist composition for positive and negative reversal as described in claim 1, characterized in that, The photo-induced acid-producing agent is o-nitrobenzyl sulfonate.

4. The photoresist composition for positive and negative reversal as described in claim 1, characterized in that, The mass fraction of PDHF is 3wt% to 5wt%, and the mass of the photoacid-producing agent is 20wt% to 30wt% of the mass of PDHF.

5. Patterning application of the photoresist composition for positive and negative reversal as described in any one of claims 1-4.

6. The patterned application as described in claim 5, characterized in that, include: The positive and negative reverse photoresist composition is coated onto a substrate and exposed, and developed for 20s to 60s to obtain a pattern.

7. The patterned application as described in claim 6, characterized in that, The exposure conditions are: 20 mJ / cm² when a mask is used. 2 ~200mJ / cm 2 Expose at a dose; The pattern is a negative pattern.

8. The patterned application as described in claim 6, characterized in that, The exposure conditions are as follows: first use 20mJ / cm 2 ~200mJ / cm 2 Full exposure was performed using the appropriate dose, followed by exposure with a mask at 300 mJ / cm². 2 ~2000mJ / cm 2 Expose at a dose; The pattern is a positive pattern.

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