Polyimide positive photoresist based on base deactivation mechanism

Abstract

The application discloses a polyimide positive photoresist based on alkali deactivation mechanism, which comprises a polyamide acid resin, an alkali catalyst, a photo acid generator and a solvent, and the positive photoresist is composed of the following components (in percentage by weight, the sum of the components is 100%): the polyamide acid resin 10%-50%; the alkali catalyst 0.5%-10%; the photo acid generator 0.5%-10%; and the solvent 50%-90%. The application provides a polyimide positive photoresist based on alkali deactivation mechanism, and the photoresist belongs to a chemical amplification photoresist, has high photosensitivity, and for example, the exposure dose can be reduced to 50-70 mj / cm 2 Meanwhile, the loss of the imidized photoresist thickness is smaller, and the production efficiency of customers can be greatly improved, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of photoresist technology, and more specifically to a polyimide positive photoresist based on an alkali deactivation mechanism. Background Technology

[0002] Integrated circuit (IC) packaging is an indispensable link in the integrated circuit industry chain. Packaging refers to the process of processing tested wafers into individual chips, protecting the circuit chips from the influence of the surrounding environment, playing a role in protecting the chips, enhancing thermal conductivity, and connecting the internal circuits of the chips with external circuits. Packaging and testing has become an important part of my country's integrated circuit industry.

[0003] A key photosensitive insulating material is needed in encapsulation: photosensitive polyimide, which comes in positive and negative forms. In current processes, positive photosensitive polyimide photoresists commonly use a combination of polyamic acid and a photosensitive compound containing diazonaphthoquinone (DNQ). A positive image is formed by altering the solubility of DNQ through exposure. However, this method has significant drawbacks. Firstly, DNQ requires a relatively high exposure dose, typically 150 mJ / cm². 2 The above reduces production efficiency. Secondly, during the high-temperature imidization process in the later stage, the presence of DNQ and the high addition amount will lead to 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 temperatures above 300°C. Summary of the Invention

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

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A positive polyimide photoresist based on an alkaline deactivation mechanism comprises polyamic acid resin, an alkaline catalyst, a photoacid generator, and a solvent. The composition of the positive photoresist is as follows (by weight percentage, all components add up to 100%):

[0007] Polyamic acid resin 10%-50%;

[0008] Alkaline catalyst 0.5%-10%;

[0009] Photo-acid generator 0.5%-10%;

[0010] Solvent content: 50%-90%.

[0011] Preferably, the main resin is a polyamic acid resin with the following structural formula, and the molecular weight of the resin is 10,000-100,000.

[0012]

[0013] Preferably, the positive photoresist further contains an alkaline catalyst, including tetraethylammonium chloride, tetrabutylammonium chloride, tetraethylammonium tetrafluoroborate, triethanolamine, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, N,N-dimethylcyclohexylamine, azidooctane, trioctylamine, etc. The photoresist of the present invention contains one or more of the above alkaline catalysts.

[0014] Preferably, the positive photoresist further contains a photoacid generator, which is a photoacid generator that can be photosensitive at 365nm and generate an acidic compound that deactivates the alkaline catalyst. This includes nonionic and ionic types, such as methyldichloromethyltriazine, naphthimide trifluoromethanesulfonate, p-methoxyphenylacetonitrile p-toluenesulfonate, thionium hexafluoroantimonate, and iodonium p-toluenesulfonate.

[0015] Preferably, the solvent for the positive photoresist is a combination of at least one of 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 the aforementioned solvents.

[0016] As can be seen from the above technical solution, compared with the prior art, the present invention provides a polyimide positive photoresist based on the alkali deactivation mechanism. This photoresist belongs to chemically amplified photoresist and has strong photosensitivity. Taking a 3-micron photoresist thickness as an example, the exposure dose can be reduced to 50-70 mJ / cm. 2 This significantly improves customer production efficiency and reduces production costs. In addition, since it does not contain DNQ, the film thickness loss during imidization can be reduced to below 20%, and the imidization temperature can be reduced to 200°C due to the presence of the catalyst. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] This invention discloses a polyimide positive photoresist based on an alkali deactivation mechanism.

[0019] A positive polyimide photoresist based on an alkaline deactivation mechanism comprises polyamic acid resin, an alkaline catalyst, a photoacid generator, and a solvent. The composition of the positive photoresist is as follows (by weight percentage, all components add up to 100%):

[0020] Polyamic acid resin 10%-50%;

[0021] Alkaline catalyst 0.5%-10%;

[0022] Photo-acid generator 0.5%-10%;

[0023] Solvent content: 50%-90%.

[0024] After the photoresist film is made, the alkaline catalyst in the non-exposed area catalyzes the imidization reaction of polyamic acid, making it insoluble in the alkaline developer. After the exposed area is exposed to ultraviolet light at a wavelength of 365nm, the photoacid generator produces acidic compounds that react with the alkaline catalyst to deactivate it and no longer catalyze the imidization reaction. After the film is developed by the alkaline developer, a positive image is formed.

[0025] Preferably, the main resin is a polyamic acid resin with the following structural formula, and the molecular weight of the resin is 10,000-100,000. The above resin possesses excellent physicochemical properties, suitable dissolution rate, and good film-forming properties.

[0026]

[0027] Preferably, the positive photoresist further contains an alkaline catalyst, including tetraethylammonium chloride, tetrabutylammonium chloride, tetraethylammonium tetrafluoroborate, triethanolamine, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, N,N-dimethylcyclohexylamine, azidooctane, trioctylamine, etc. The photoresist of the present invention contains one or more of the above alkaline catalysts, and the acidic compounds generated after exposure can neutralize the alkaline catalyst, causing it to lose its catalytic ability.

[0028] Preferably, the positive photoresist further contains a photoacid generator, which is a photoacid generator that can be photosensitive at 365nm and generate an acidic compound that deactivates the alkaline catalyst. This includes nonionic and ionic types, such as methyldichloromethyltriazine, naphthimide trifluoromethanesulfonate, p-methoxyphenylacetonitrile p-toluenesulfonate, thionium hexafluoroantimonate, and iodonium p-toluenesulfonate.

[0029] Preferably, the solvent for the positive photoresist is a combination of at least one of 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 the aforementioned solvents.

[0030] Example 1:

[0031] The component weight ratio of the positive photoresist composition in this embodiment is as follows: after mixing the components, they are fully dissolved in the solvent propylene glycol methyl ether acetate, and then filtered through a filter membrane with a pore size of 0.2 micrometers to obtain the positive photoresist composition, wherein the polyamic acid resin Mw in this embodiment is 20000.

[0032]

[0033] Example 2:

[0034] The component weight ratio of the positive photoresist composition in this embodiment is as follows: after mixing the components, they are fully dissolved in the solvent propylene glycol methyl ether acetate, and then filtered through a filter membrane with a pore size of 0.2 micrometers to obtain the positive photoresist composition, wherein the polyamic acid resin Mw in this embodiment is 20000.

[0035]

[0036] Example 3:

[0037] The component weight ratio of the positive photoresist composition in this embodiment is as follows: after mixing the components, they are fully dissolved in the solvent propylene glycol methyl ether, and then filtered through a filter membrane with a pore size of 0.2 micrometers to obtain the positive photoresist composition, wherein the polyamic acid resin Mw in this embodiment is 20000.

[0038]

[0039] Example 4:

[0040] The component weight ratio of the positive photoresist composition in this embodiment is as follows: After mixing the components, they are fully dissolved in the solvent N-methylpyrrolidone, and then filtered through a filter membrane with a pore size of 0.2 micrometers to obtain the positive photoresist composition, wherein the polyamic acid resin Mw in this embodiment is 20000.

[0041]

[0042] Example 5:

[0043] The difference between this embodiment and Example 1 is that the polyamic acid resin Mw in this embodiment is 40000, while the rest are the same as in Example 1, resulting in a positive photoresist composition.

[0044] Example 6:

[0045] The difference between this embodiment and Example 1 is that the polyamic acid resin Mw in this embodiment is 60000, while the rest are the same as in Example 1, resulting in a positive photoresist composition.

[0046] Example 7:

[0047] The difference between this embodiment and Example 1 is that the amount of methyldichloromethyltriazine in this embodiment is 4g, while the rest is the same as in Example 1, resulting in a positive photoresist composition.

[0048] Comparative Example 1:

[0049] StarTech's non-chemically amplified polyimide positive photoresist SUN-PI100P.

[0050] Experimental Example 1

[0051] The positive photoresist compositions of Examples 1-7 and the positive photoresist SUN-PI100P of Comparative Example 1 were spin-coated onto the treated substrates, respectively. They were then pre-baked with a hot plate (PAB) at 100°C for 60s, and the rotation speed was adjusted to make the film thickness 3 micrometers after drying. The film was exposed at 365nm through a photomask (with a pattern size of 10 micrometers lines), and then pre-baked with a hot plate (PEB) at 130°C for 60s. After immersion development with 2.38wt% TMAH for 60s, the photolithography process was completed after rinsing with deionized water, and a positive image was obtained. The line width in the image was measured. When the line width was 10 micrometers (the same as the photomask size), the exposure dose was recorded. The data are shown in Table 1.

[0052] Table 1

[0053]

[0054] Then, the polyimide photoresist was heat-treated in an oven under nitrogen protection at a heating rate of 4℃ / min for 1 hour at 200℃ (300℃ for comparison) to completely cure the photoresist. The photoresist thickness before and after curing (tested using Filmetrics F20-UV) is shown in Table 2.

[0055] Table 2

[0056]

[0057]

[0058] Experimental data show that the polyimide positive photoresist based on the alkali deactivation mechanism provided by this invention has strong photosensitivity. Taking a 3-micron photoresist thickness as an example, the exposure dose can be reduced to 50-70 mJ / cm. 2 The film thickness loss due to imidization can be reduced to below 20%.

[0059] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0060] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A polyimide positive photoresist based on an alkali deactivation mechanism, characterized in that, Its components include polyamic acid resin, alkaline catalyst, photoacid generator, and solvent. The positive photoresist has the following composition (by weight percentage, all components add up to 100%): Polyamic acid resin 10%-50%; Alkaline catalyst 0.5%-10%; Photo-acid generator: 0.5%-10%; Solvent 50%-90%; The main resin is a polyamic acid resin with the following structural formula, and the molecular weight of the resin is 60,000; ； The positive photoresist also contains an alkaline catalyst: tetraethylammonium chloride; The positive photoresist also contains a photoacid-generating agent: methyldichloromethyltriazine; The solvent for the positive photoresist is propylene glycol methyl ether acetate.

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