TW201311883A - Photoresist cleaning liquid - Google Patents

Abstract

Disclosed is a cleaning liquid which has low etching property and is suitable to clean thicker photoresist. This low etching photoresist cleaning liquid contains (a) potassium hydroxide, (b) pyrrolidone solvent, (c) sulfone solvent, (d) pentaerythritol, (e) alkylol amine, (f) resorcinol and (g) benzotriazole corrosion inhibitor. The low etching photoresist cleaning liquid can be used to remove photoresist and other residues on metal, metal alloy or dielectric substance and has low etching rate for metal such as Cu, etc. Therefore, the low etching photoresist cleaning liquid has a good application prospect in the field of micro-electronics such as semiconductor chip cleaning, etc.

Description

Photoresist (lithography) glue cleaning solution

The invention relates to a cleaning liquid in a semiconductor process, in particular to a low-etching thick photoresist (or lithography, the same below) glue cleaning liquid.

In a typical semiconductor manufacturing process, a mask (or a photomask, the same hereinafter) of a photoresist is formed on a surface of a metal such as cerium oxide, Cu (copper) or the like, and a low-k material, and the pattern is transferred after exposure. After obtaining the desired circuit pattern, it is necessary to remove the residual photoresist before proceeding to the next step. For example, in a wafer microsphere (or bump, the same below) implantation technology, a photoresist is required to form a mask, which needs to be removed after the microsphere is successfully implanted, but The photoresist is thicker and it is often difficult to remove completely. A more common method for improving the removal effect is to extend the soaking time, increase the soaking temperature, and use a more aggressive solution, but this often results in corrosion of the wafer substrate and corrosion of the microspheres, resulting in a significant reduction in wafer yield.

At present, the photoresist cleaning liquid is mainly composed of a polar organic solvent, a strong alkali, and/or water, and the photoresist on the semiconductor wafer is removed by immersing the semiconductor wafer in the cleaning liquid or rinsing the semiconductor wafer with the cleaning liquid. Among them, the strong bases commonly used are mainly inorganic metal hydroxides (such as potassium hydroxide and the like) and organic hydroxides such as tetramethylammonium hydroxide.

For example, JP1998239865 consists of an alkaline cleaning solution consisting of tetramethylammonium hydroxide (TMAH), dimethyl hydrazine (DMSO), 1,3-dimethyl-2-imidazolidinone (DMI) and water to immerse the wafer. In the cleaning solution, a thick film photoresist of 20 μm or more on the metal and dielectric substrate was removed at 50 to 100 °C. The corrosion of the semiconductor wafer substrate is slightly higher, and the photoresist on the semiconductor wafer cannot be completely removed, and the cleaning ability is insufficient; WO2006/056298 A1 utilizes tetramethylammonium hydroxide (TMAH), dimethyl alum (DMSO). ), ethylene glycol (EG) and water constitute an alkaline cleaning solution for cleaning 50-100 micron thick photoresist, and basically no corrosion to metallic copper; US6040117 utilizes TMAH, dimethyl sulfoxide (DMSO) An alkaline cleaning solution consisting of 1,3-dimethyl-2-imidazolidinone (DMI) and water, and the wafer is introduced into the cleaning solution to remove 20 μm or more of the metal and dielectric substrate at 50 to 100 ° C. Thick film photoresist. For another example, US 5529887 consists of an alkaline cleaning solution consisting of potassium hydroxide (KOH), an alkyl glycol monoalkyl ether, a water-soluble fluoride and water, etc., the wafer is immersed in the cleaning solution, and the metal is removed at 40 to 90 ° C. A thick film photoresist on a dielectric substrate. It has a high corrosion to the semiconductor wafer substrate.

It can be seen that finding a more effective metal corrosion inhibitor and a solvent system for dissolving more photoresist is a priority for the improvement of such photoresist paste cleaning liquid.

The technical problem to be solved by the invention is to provide a strong cleaning ability for the thick film photoresist by aiming at the defects of the existing thick film photoresist cleaning liquid which have insufficient cleaning ability or strong corrosion to the semiconductor wafer pattern and the substrate. And a photoresist paste cleaning agent which is less corrosive to the semiconductor wafer pattern and the substrate.

The technical solution adopted by the present invention to solve the above technical problems is: a cleaning liquid for a thick film photoresist, the cleaning liquid comprising (a) potassium hydroxide, (b) pyrrolidone solvent, (c) anthraquinone solvent, (d) pentaerythritol, (e) an alcohol amine, (f) resorcinol, (g) a benzotriazole corrosion inhibitor.

Wherein, the mass percentage of the potassium hydroxide in the cleaning solution is preferably from 0.1 to 6%; the mass percentage of the pyrrolidone solvent in the cleaning solution is preferably from 1 to 90%; the terpenoid solvent is in the cleaning The mass percentage in the liquid is preferably from 1 to 90%; the mass percentage of the pentaerythritol in the cleaning solution is preferably from 0.1 to 15%; and the mass percentage of the alcohol amine in the cleaning solution is preferably from 0.1 to 55%; The mass percentage of resorcin in the cleaning liquid is preferably 0.01 to 10%; and the mass percentage of the benzotriazole corrosion inhibitor in the cleaning liquid is preferably 0.1 to 5%.

The pyrrolidone-based solvent described in the present invention is N-methylpyrrolidone, N-ethylpyrrolidone, N-hydroxyethylpyrrolidone, and N-cyclohexylpyrrolidone.

The hydrazine-based solvents described in the present invention are hydrazine and hydrazine. Preferably, the hydrazine is dimethyl hydrazine; the hydrazine is preferably cyclobutyl hydrazine, dimethyl hydrazine and 2,4-dimethylcyclobutyl fluorene.

The alcohol amine described in the present invention is one of monoethanolamine, diethanolamine, triethanolamine, n-propanolamine, isopropanolamine, 2-(diethylamino)ethanol, ethyldiethanolamine and diglycolamine or Several. The presence of the alcoholamine is beneficial to increase the solubility of potassium hydroxide and pentaerythritol in the system and to protect the metal microspheres.

The benzotriazole corrosion inhibitors described in the present invention are benzotriazole, methylbenzotriazole, 1-hydroxybenzotriazole, 5-carboxybenzotriazole and/or One or more of their potassium salts.

The low etch photoresist photoresist cleaning liquid of the invention can clean the photoresist of thickness of 100 μm or more at room temperature to 90 ° C, and because of the resorcinol and benzotriazole corrosion inhibitor contained therein Alcoholamine can form a protective film on the surface of metal microspheres and metal under the metal microspheres (UBM), thereby reducing the corrosion of the substrate. A composite solvent system of a pyrrolidone solvent, an anthraquinone solvent and pentaerythritol is advantageous for improving the removal efficiency of the photoresist. The specific method is as follows: The photoresist wafer containing the photoresist is immersed in the low-etching photoresist adhesive of the present invention, and after being immersed at room temperature to 90 ° C for a suitable period of time, it is taken out and washed, and then dried by high-purity nitrogen gas.

The cleaning liquid of the present invention can be obtained by simply mixing and mixing the above components. The cleaning liquid of the present invention can be used over a wide temperature range, generally ranging from room temperature to 90 °C. The reagents and starting materials used in the present invention are commercially available.

The positive effects of the present invention are:

(1) The photoresist cleaning liquid of the present invention can be applied to the cleaning of a thick (thickness greater than 100 μm) photoresist, and has a lower etching rate for metals such as Cu (copper).

(2) The low-etching photoresist paste cleaning liquid of the present invention can be used to clean the photoresist at room temperature to 90 °C.

(3) The alcohol amine solvent used in the formulation improves the solubility of potassium hydroxide and pentaerythritol in the system and is beneficial to the protection of the metal microspheres.

(4) The compound solvent system of pyrrolidone solvent, terpene solvent and pentaerythritol used in the formulation further improves the removal ability of the photoresist.

(5) Resorcinol/benzotriazole corrosion inhibitors used in the formulation effectively inhibit corrosion of metals such as copper, tin and lead.

The invention is further illustrated by the following examples, which are not intended to limit the invention.

Examples 1 to 31

Table 1 shows Examples 1 to 31 of the present invention which are suitable for thicker photoresist paste cleaning liquids. According to the formulation in the table, the components are uniformly mixed to prepare the cleaning liquids of the respective examples.

Effect embodiment

In order to further investigate the cleaning of such cleaning liquids, the present invention adopts the following technical means: a semiconductor wafer containing a negative acrylate photoresist (having a thickness of about 120 μm and exposed and etched) (bump package crystal) The wafer was immersed in a cleaning agent and immersed at 25 to 90 ° C for 15 to 120 minutes, and then the semiconductor wafer was taken out and washed with deionized water and then dried with high purity nitrogen gas. The cleaning effect of the photoresist and the corrosion of the wafer by the cleaning solution are shown in Table 2.

Table 2 Example 7~30 wafer cleaning

It can be seen from Table 2 that the cleaning liquid of the invention has a good cleaning effect on the thick film photoresist, has a wide temperature range, and has good corrosion inhibition effect on the metal microspheres and the metal copper.

Claims (13)

A photoresist (lithographic) paste cleaning solution comprising: (a) potassium hydroxide, (b) pyrrolidone solvent, (c) anthraquinone solvent (d) pentaerythritol, (e) an alcohol amine, (f) Hydroquinone, and (g) benzotriazole corrosion inhibitors. The cleaning liquid according to claim 1, wherein the potassium hydroxide is contained in an amount of 0.1 to 6% by mass. The cleaning liquid according to claim 1, wherein the pyrrolidone solvent is contained in an amount of from 1 to 90% by mass. The cleaning liquid according to claim 1, characterized in that the content of the terpenoid solvent is from 1 to 90% by mass. The cleaning liquid according to claim 1, wherein the pentaerythritol is contained in an amount of 0.1 to 15% by mass. The cleaning liquid according to claim 1, characterized in that the content of the alcoholamine is 0.1 to 55% by mass. The cleaning liquid according to claim 1, characterized in that the content of the resorcin is 0.01 to 10% by mass. The cleaning liquid according to claim 1, wherein the benzotriazole corrosion inhibitor is contained in an amount of 0.1 to 5% by mass. The cleaning solution according to claim 1, wherein the pyrrolidone solvent is one selected from the group consisting of N-methylpyrrolidone, N-ethylpyrrolidone, N-hydroxyethylpyrrolidone and N-cyclohexylpyrrolidone or A variety. The cleaning solution according to claim 1, wherein the terpenoid solvent is hydrazine and/or hydrazine. The cleaning solution according to claim 1, wherein the alcoholamine is selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, n-propanolamine, isopropanolamine, 2-(diethylamino)ethanol, and B. One or more of bisethanolamine and diglycolamine. The cleaning solution according to claim 1, wherein the benzotriazole corrosion inhibitor is selected from the group consisting of benzotriazole, methylbenzotriazole, and 1-hydroxybenzotriazole. One or more of 5-carboxybenzotriazole and their potassium salts. The cleaning solution according to claim 10, characterized in that the hydrazine is dimethyl hydrazine; the hydrazine is cyclobutyl hydrazine, dimethyl hydrazine and/or 2,4-dimethyl ring. Ding Wei.