Polyimide positive photoresist based on acid deactivation mechanism

Abstract

The invention discloses a polyimide positive photoresist based on an acid deactivation mechanism, which comprises the following components in percentage by weight: 10-50% of polyamic acid resin, 10-50% of acid catalyst, 10-50% of photoinduced deactivator and 10-50% of solvent. 0.5%-10% of an acidic catalyst; 0.5%-10% of a photoinduced deactivating agent; and 50%-90% of a solvent. The invention provides a polyimide positive photoresist based on an acid deactivation mechanism, the photoresist belongs to a chemical amplification photoresist, the photosensitivity is strong, the exposure dose can be reduced to 50-70mj / cm < 2 > by taking the photoresist thickness of 3 microns as an example, meanwhile, the imidization photoresist thickness loss is smaller, the production efficiency can be greatly improved, and the production cost can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of photoresists, and more particularly to a polyimide positive photoresist based on an acid deactivation mechanism. Background Art

[0002] Integrated circuit (IC) packaging is an essential link in the integrated circuit industry chain. Packaging refers to the process of processing tested wafers to obtain independent chips, which protects the circuit chips from the surrounding environment, protects the chips, enhances thermal conductivity, and communicates the internal and external circuits of the chips. Packaging and testing have become an important part of my country's integrated circuits.

[0003] A key photosensitive insulating material is required in packaging, which is photosensitive polyimide, which is divided into positive and negative types. In the current process, positive photosensitive polyimide photoresists generally use polyamide and photosensitive compounds containing diazonaphthoquinone (DNQ) to form a positive image by changing the solubility of DNQ through exposure. However, the defects of this method are also obvious. First, the exposure dose required for DNQ is large, usually 150mj / cm 2 The above reduces the production efficiency. Secondly, during the later high-temperature imidization, the presence of DNQ and the high addition amount will cause an extremely high film thickness loss of more than 30%. At the same time, the temperature and time conditions required for imidization are also more stringent, usually requiring more than 300°C. Summary of the invention

[0004] In view of this, the present invention provides a polyimide positive photoresist based on an acid deactivation mechanism.

[0005] To achieve the above object, the present invention provides the following technical solutions: A polyimide positive photoresist based on an acid deactivation mechanism, wherein the positive photoresist comprises the following components (by weight percentage, the sum of the components is 100%): Polyamic acid resin 10%-50%; Acid catalyst 0.5%-10%; Photodeactivator 0.5%-10%; Solvent 50%-90%.

[0006] Preferably, the main resin is a polyamic acid resin having the following structural formula, and the molecular weight of the resin is 10000-100000 .

[0007] Preferably, the acidic catalyst includes an organic acid or an inorganic acid, wherein the organic acid includes formic acid, acetic acid, propionic acid, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and p-toluenesulfonic acid; the inorganic acid includes hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and hydrofluoric acid. The photoresist of the present invention contains one or more of the above acidic catalysts.

[0008] Preferably, the photodeactivator refers to a compound that is photosensitized at 365 nm and deactivates the acidic catalyst, including benzyl (4-methoxyphenyl) aminomethyl ester.

[0009] Preferably, the solvent of the positive photoresist includes ethylene glycol methyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl acetate, ethyl lactate, γ-butyrolactone, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide or a combination of at least one of the foregoing solvents.

[0010] It can be seen from the above technical solution that compared with the prior art, the present invention provides a polyimide positive photoresist based on an acid deactivation mechanism. This photoresist is a chemically amplified photoresist with strong photosensitivity. Taking a 3-micron thick photoresist as an example, the exposure dose can be reduced to 50-70 mj / cm2, which greatly improves production efficiency and reduces production costs. In addition, since it does not contain DNQ, the film thickness loss of imidization can be reduced to less than 20%. Due to the presence of a catalyst, the imidization temperature can be reduced to 200°C. DETAILED DESCRIPTION

[0011] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0012] The embodiment of the invention discloses a polyimide positive photoresist based on an acid deactivation mechanism.

[0013] The components of the photoresist of the present invention include polyamic acid resin, acidic catalyst, photodeactivator and solvent. After the photoresist film is made, the acidic catalyst in the non-exposed area catalyzes the polyamic acid to undergo imidization reaction, thereby making it insoluble in alkaline developer. After the exposed area is exposed to ultraviolet light with a wavelength of 365nm, the photodeactivator generates a compound that reacts with the acidic catalyst to deactivate it and no longer catalyzes the imidization reaction. After the film is developed with an alkaline developer, a positive image is formed.

[0014] The main resin is polyamic acid resin. The structural formula is as follows. The above resin has excellent physical and chemical properties, suitable dissolution rate, and good film-forming properties. The molecular weight of the resin is 10000-100000. .

[0015] The positive photoresist also contains an acidic catalyst, including an organic acid or an inorganic acid, wherein the organic acid includes formic acid, acetic acid, propionic acid, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and p-toluenesulfonic acid; the inorganic acid includes hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and hydrofluoric acid. The photoresist of the present invention contains one or more of the above acidic catalysts.

[0016] The positive photoresist also contains a photodeactivator, which refers to a compound that is photosensitizing at 365nm and deactivates the acidic catalyst, including benzyl (4-methoxyphenyl) aminomethyl ester. The special molecular structure of this photodeactivator makes it strongly absorb ultraviolet light at a wavelength of 365nm, and can effectively deactivate the acidic catalyst.

[0017] The solvent of the positive photoresist of the present invention includes ethylene glycol methyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl acetate, ethyl lactate, γ-butyrolactone, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide or a combination of at least one of the aforementioned solvents.

[0018] The positive photoresist of the present invention is composed of the following (by weight percentage, the sum of all components is 100%): 10%-50% polyamic acid resin; 0.5%-10% acid catalyst; 0.5%-10% photodeactivator; 50%-90% solvent. Embodiment 1:

[0019] The weight ratio of the components of the positive photoresist composition of this embodiment is as follows: after mixing the components, use the solvent propylene glycol methyl ether acetate to fully dissolve them, and then filter them with a filter membrane with a pore size of 0.2 microns to obtain a positive photoresist composition, wherein the polyamic acid resin Mw of this embodiment is 20,000.

[0020] Polyamic acid resin 50g Acetic acid 0.5g Benzyl (4-methoxyphenyl) aminomethyl ester 0.5g Propylene glycol methyl ether acetate 100g Embodiment 2:

[0021] The weight ratio of the components of the positive photoresist composition of this embodiment is as follows: after mixing the components, use the solvent propylene glycol methyl ether acetate to fully dissolve them, and then filter them with a filter membrane with a pore size of 0.2 microns to obtain a positive photoresist composition, wherein the polyamic acid resin Mw of this embodiment is 20,000.

[0022] Polyamic acid resin 50g Ethylsulfonic acid 0.5g Benzyl (4-methoxyphenyl) aminomethyl ester 1g Propylene glycol methyl ether acetate 100g Embodiment three:

[0023] The weight ratio of the components of the positive photoresist composition of this embodiment is as follows: after mixing the components, use the solvent propylene glycol methyl ether to fully dissolve them, and then filter them with a filter membrane with a pore size of 0.2 microns to obtain a positive photoresist composition, wherein the polyamic acid resin Mw of this embodiment is 20,000.

[0024] Polyamic acid resin 50g sulfuric acid 0.5g Benzyl (4-methoxyphenyl) aminomethyl ester 0.5g Propylene glycol methyl ether 100g Embodiment 4:

[0025] The weight ratio of the components of the positive photoresist composition of this embodiment is as follows: after mixing the components, fully dissolve them with solvent N-methylpyrrolidone, and then filter them with a filter membrane with a pore size of 0.2 microns to obtain a positive photoresist composition, wherein the polyamic acid resin Mw of this embodiment is 20,000.

[0026] Polyamic acid resin 50g sulfuric acid 0.5g Benzyl (4-methoxyphenyl) aminomethyl ester 0.5g Methylpyrrolidone 100g Embodiment five:

[0027] The difference between this embodiment and embodiment 1 is that the Mw of the polyamic acid resin in this embodiment is 40000, and the rest is the same as embodiment 1, to obtain a positive photoresist composition. Embodiment six:

[0028] The difference between this embodiment and embodiment 1 is that the Mw of the polyamic acid resin in this embodiment is 60000, and the rest is the same as embodiment 1, to obtain a positive photoresist composition. Embodiment seven:

[0029] The difference between this embodiment and embodiment 1 is that the amount of benzyl (4-methoxyphenyl) aminomethyl ester in this embodiment is 4 g, and the rest is the same as that in embodiment 1, to obtain a positive photoresist composition. Comparative Example 1:

[0030] SUN-PI100P is a non-chemically amplified polyimide positive photoresist produced by SUNTEK. Experimental Example 1

[0031] The positive photoresist compositions of Examples 1-7 and the positive photoresist SUN-PI100P of Comparative Example 1 were spin-coated on the treated substrates respectively, and then pre-baked on a hot plate (PAB) for 100°C / 60s. The rotation speed was adjusted so that the film thickness after drying was 3 μm. After passing through a mask (with a pattern size of 10 μm lines) and exposing at 365nm using an exposure machine, the substrates were then hot-baked (PEB) for 130°C / 60s. The substrates were immersed and developed with 2.38wt% TMAH for 60s. After washing with deionized water, the photolithography process was completed to obtain a positive image. The width of the lines in the image was measured. When the line width was 10 μm (the same as the mask size), the exposure dose was recorded. The data are shown in Table 1.

[0032] Table 1 sample Exposure dose (mJ / cm2) Example 1 67 Example 2 61 Example 3 66 Example 4 65 Example 5 63 Example 6 56 Example 7 52 Comparative Example 1 170 Then, an oven was used under nitrogen protection to perform heat treatment at 200°C (300°C for the comparative example) for 1 hour at a heating rate of 4°C / min to completely cure the polyimide photoresist. The data of the photoresist thickness before and after curing (tested using Filmetrics F20-UV) are shown in Table 2.

[0033] Table 2 sample Before curing (um) After curing (um) Glue thickness loss (%) Example 1 2.84 2.40 15.5 Example 2 2.86 2.38 16.8 Example 3 2.86 2.42 15.4 Example 4 2.85 2.40 15.8 Example 5 2.90 2.44 15.9 Example 6 2.92 2.50 14.4 Example 7 2.87 2.32 19.2 Comparative Example 1 2.88 1.95 32.3 Experimental data show that the polyimide positive photoresist based on the acid deactivation mechanism provided by the present invention has strong photosensitivity. Taking 3 micron thick photoresist as an example, the exposure dose can be reduced to 50~70mj / cm2, and the film thickness loss due to imidization can be reduced to less than 20%.

[0034] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0035] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A polyimide positive photoresist based on an acid deactivation mechanism, the components of which are as follows by weight percentage: Polyamic acid resin 10%-50%; Acid catalyst 0.5%-10%; Photodeactivator 0.5%-10%; Solvent 50%-90%.

2. The positive photoresist according to claim 1, characterized in that The main resin is polyamic acid resin, the structural formula is as follows, and the molecular weight of the resin is 10000-100000 。 3. The positive photoresist according to claim 1, characterized in that The acidic catalyst includes an organic acid or an inorganic acid, wherein the organic acid includes formic acid, acetic acid, propionic acid, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and p-toluenesulfonic acid; the inorganic acid includes hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and hydrofluoric acid. The photoresist of the present invention contains one or more of the above acidic catalysts.

4. The positive photoresist according to claim 1, characterized in that The photodeactivator refers to a compound that is photosensitive at 365 nm and deactivates the acidic catalyst, including benzyl (4-methoxyphenyl) aminomethyl ester.

5. The positive photoresist according to claim 1, characterized in that The solvent of the positive photoresist includes ethylene glycol methyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl acetate, ethyl lactate, γ-butyrolactone, N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide or a combination of at least one of the foregoing solvents.

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