Cleaning agent for removing photoresist residues and preparation method thereof

Abstract

The invention relates to the field of cleaning agents for semiconductor industry, and provides a cleaning agent for removing photoresist residues and a preparation method thereof, the cleaning agent comprises the following raw materials by weight: 8-12 parts of an inorganic alkali, 1-4 parts of an organic alkali, 2-5 parts of a corrosion inhibitor, 0.5-3 parts of a surfactant, 40-60 parts of an organic solvent, and 10-20 parts of ultrapure water. According to the cleaning agent for removing the photoresist residues, the residual photoresist can be thoroughly removed, and the corrosion to a base material is low.

Description

Technical Field

[0001] This invention relates to the field of cleaning agents for the semiconductor industry, and particularly to a cleaning agent for removing photoresist residues and its preparation method. Background Technology

[0002] The fabrication of semiconductor devices involves multiple photolithography processes, and photoresist is an essential material used in these processes. Photoresist is applied to the surfaces of silicon, low-k materials, and metals such as Al or Cu. After exposure, development, and etching to form circuits, the photoresist layer must be thoroughly removed before proceeding to the next process step. Photoresist residue mainly consists of cross-linked polymers, photoacid-generating agent decomposition products, and metal halides. Incomplete removal can lead to defects in subsequent thin film deposition, corrosion of metal interconnects, and device leakage, directly impacting wafer yield.

[0003] In the semiconductor industry, stripping photoresist and its residues requires dry ashing to remove most of the photoresist layer, followed by the use of photoresist cleaners to remove the remaining photoresist layer. Currently, most cleaning solutions on the market are traditional alkaline cleaners and fluorinated cleaners, which pose corrosion risks as well as environmental and cost issues. As semiconductor process dimensions become smaller and smaller, high-speed rotating single-wafer cleaning is becoming more and more widely used. Therefore, the corrosion control of metallic and non-metallic materials is becoming more and more stringent, making the use and selection of corrosion inhibitors increasingly important.

[0004] CN 119439657 A discloses a photoresist cleaning agent and its preparation method and application. The photoresist cleaning agent includes the following components: alkali, organic solvent, corrosion inhibitor and surfactant, wherein the corrosion inhibitor includes polyol and azole corrosion inhibitor. The prepared photoresist cleaning agent has multiple functions such as stripping, dispersing, wetting, emulsifying, cleaning, dewaxing and degreasing, and has good protective performance for metal circuits and semiconductor substrates. However, the azole corrosion inhibitors selected in this application, such as benzotriazole and mercaptobenzothiazole, are not easily biodegradable and cause environmental safety problems.

[0005] Therefore, there is an urgent need on the market for a cleaning agent that can thoroughly remove residual photoresist and has low corrosiveness to the substrate. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention discloses a cleaning agent for removing photoresist residue. The cleaning agent is mainly composed of inorganic and organic bases, and is designed to incorporate corrosion inhibitors composed of a certain proportion of glycine derivatives, sodium phytate and sorbitol, as well as surfactants, so that it can thoroughly remove residual photoresist and has low corrosiveness to the substrate.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a cleaning agent for removing photoresist residue, which, by weight, comprises the following raw materials: 8-12 parts of inorganic alkali, 1-4 parts of organic alkali, 2-5 parts of corrosion inhibitor, 0.5-3 parts of surfactant, 40-60 parts of organic solvent, and 10-20 parts of ultrapure water.

[0008] In some embodiments of the present invention, the inorganic base is sodium hydroxide or potassium hydroxide.

[0009] In some embodiments of the present invention, the organic base is any one of monoethanolamine, diethanolamine, and triethanolamine.

[0010] In some embodiments of the present invention, the corrosion inhibitor is a mixture of glycine derivatives, sodium phytate, and sorbitol.

[0011] In some embodiments of the present invention, the mass ratio of glycine derivative, sodium phytate and sorbitol in the corrosion inhibitor is 1:(0.4-0.6):(0.4-0.6).

[0012] Preferably, the mass ratio of glycine derivative, sodium phytate and sorbitol in the corrosion inhibitor is 1:0.5:0.5.

[0013] In some embodiments of the present invention, the method for preparing the glycine derivative includes the following steps: Glycine tert-butyl hydrochloride and sodium bicarbonate were added to acetonitrile, stirred, and then bromododecane and a catalyst were added. The mixture was refluxed, rotary evaporated, and then added to dichloromethane. After washing, the mixture was rotary evaporated and then added to anhydrous ethanol. The mixture was stirred, and then sodium ethoxide-ethanol mixed solution was added. The mixture was stirred, filtered, washed, and dried to obtain the glycine derivative.

[0014] The molar ratio of glycine tert-butyl hydrochloride to sodium bicarbonate is 1:(1.5-2.2).

[0015] Preferably, the molar ratio of glycine tert-butyl hydrochloride to sodium bicarbonate is 1:2.

[0016] In some embodiments of the present invention, the molar ratio of glycine tert-butyl hydrochloride to bromododecane is 1:(0.9-1.1).

[0017] Preferably, the molar ratio of glycine tert-butyl hydrochloride to bromododecane is 1:1.

[0018] Inorganic and organic alkalis are the main components for removing photoresist residues and have a highly efficient cleaning effect. However, strong alkalis have the disadvantage of being highly corrosive to semiconductor copper substrates. Organic corrosion inhibitors, such as imidazoles, have a highly efficient inhibitory effect on metal corrosion, but they pose environmental risks.

[0019] Glycine has the advantages of being environmentally friendly and biodegradable. Its amino and carboxyl groups can form stable coordination bonds with metal surfaces, thus inhibiting corrosion, making it a promising candidate for alkaline photoresist cleaning agents. However, glycine alone has limited corrosion inhibition effects on copper, its protective film is not dense enough, and its solubility in the organic solvent components of cleaning agents is limited. Increasing the proportion of water to improve solubility may reduce the cleaning agent's ability to dissolve photoresist.

[0020] The applicant first reacted glycine tert-butyl hydrochloride with sufficient sodium bicarbonate to release free amino groups, and then reacted it with bromododecane to introduce a long-chain alkyl structure. The resulting glycine derivative has both hydrophilic groups and hydrophobic long chains, which can form a double-layer adsorption film on the copper surface and improve its solubility in organic solvents, reducing the amount of ultrapure water used and ensuring the high cleaning effect of the cleaning agent on the photoresist. Furthermore, the tert-butyl group in glycine tert-butyl hydrochloride enhances steric hindrance and improves the stability of the glycine derivative. All of the above improve the corrosion inhibition effect of the glycine derivative.

[0021] Furthermore, the applicant combined the aforementioned glycine derivative with sodium phytate and sorbitol to form a corrosion inhibitor. The six phosphate groups of sodium phytate can react with Cu on the copper surface. 2+ They form stable chelates and form a hydrogen bond network with the carboxyl group of glycine derivatives. Sorbitol enhances the dispersibility of sodium phytate and glycine derivatives through hydrogen bonding. The three work synergistically to improve the corrosion inhibition effect.

[0022] In some embodiments of the present invention, the surfactant is a fatty alcohol polyoxyethylene ether.

[0023] In some embodiments of the present invention, the organic solvent is dimethyl sulfoxide or N-methylpyrrolidone.

[0024] In another aspect, the present invention provides a method for preparing a cleaning agent for removing photoresist residue, comprising the following steps: Inorganic alkali, organic alkali, corrosion inhibitor, surfactant, organic solvent and ultrapure water are mixed and stirred to obtain a cleaning agent for removing photoresist residue.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention discloses a cleaning agent for removing photoresist residue. The cleaning agent is mainly composed of inorganic base and organic base, and is designed to add corrosion inhibitor composed of a certain proportion of glycine derivative, sodium phytate and sorbitol, and is combined with surfactants, etc. Through the synergistic effect between the components, the cleaning agent can thoroughly remove the residual photoresist and has low corrosivity to the substrate.

[0026] (2) The present invention reacts glycine tert-butyl hydrochloride with sufficient sodium bicarbonate to release free amino groups, and then reacts with bromododecane to prepare glycine derivatives, which improves the corrosion inhibition effect of glycine derivatives and has good solubility in cleaning agents; furthermore, the applicant combines the above glycine derivatives with sodium phytate and sorbitol to form a corrosion inhibitor, which synergistically improves the corrosion inhibition effect of cleaning agents. Detailed Implementation

[0027] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0028] In the following examples and comparative examples, except for the glycine derivative, all other compound monomers and related reagents used were commercially available, including the fatty alcohol polyoxyethylene ether AEO-9.

[0029] Preparation Example 1 The method for synthesizing glycine derivative A includes the following steps: 0.05 mol glycine tert-butyl hydrochloride and 0.1 mol sodium bicarbonate were added to 150 ml acetonitrile and stirred for 30 min. Then, 0.05 mol dodecane bromo and 0.8 g tetrabutylammonium bromide were added, and the mixture was refluxed at 78 °C for 12 h. After removing acetonitrile by rotary evaporation, the mixture was added to 200 ml dichloromethane and washed (with saturated saline, 0.1 mol / L hydrochloric acid aqueous solution, and ultrapure water until neutral). The mixture was dried over anhydrous sodium sulfate, and after removing dichloromethane by rotary evaporation, it was added to 200 ml anhydrous ethanol and stirred for 30 min. Then, a mixed solution of 17 ml 20 wt% sodium ethoxide ethanol solution and 28 ml anhydrous ethanol was added, and the mixture was stirred at 50 °C for 20 min. The mixture was filtered, washed three times with ultrapure water, and dried under vacuum at 50 °C for 4 h to obtain glycine derivative A.

[0030] Preparation Example 2 Glycine derivative B is implemented in the same way as glycine derivative A, except that the molar amount of bromododecane is replaced with 0.04 mol.

[0031] Preparation Example 3 Glycine derivative C is implemented in the same way as glycine derivative A, except that the molar amount of bromododecane is replaced with 0.06 mol.

[0032] Example 1 A cleaning agent for removing photoresist residue comprises, by weight, the following raw materials: 10 parts sodium hydroxide, 2.5 parts monoethanolamine, 3.5 parts corrosion inhibitor, 1.5 parts fatty alcohol polyoxyethylene ether, 50 parts dimethyl sulfoxide, and 15 parts ultrapure water.

[0033] The corrosion inhibitor is a mixture of glycine derivative A, sodium phytate and sorbitol in a mass ratio of 1:0.5:0.5.

[0034] The preparation method of the cleaning agent for removing photoresist residue in this embodiment includes the following steps: Sodium hydroxide, monoethanolamine, corrosion inhibitor, surfactant, dimethyl sulfoxide and ultrapure water are mixed and stirred evenly to obtain a cleaning agent for removing photoresist residue.

[0035] Example 2 A cleaning agent for removing photoresist residue comprises, by weight, the following raw materials: 8 parts potassium hydroxide, 1 part diethanolamine, 2 parts corrosion inhibitor, 0.5 parts fatty alcohol polyoxyethylene ether, 40 parts N-methylpyrrolidone, and 10 parts ultrapure water.

[0036] The corrosion inhibitor is a mixture of glycine derivative A, sodium phytate, and sorbitol in a mass ratio of 1:0.4:0.4.

[0037] The preparation method of the cleaning agent for removing photoresist residue in this embodiment includes the following steps: Potassium hydroxide, diethanolamine, corrosion inhibitor, surfactant, N-methylpyrrolidone, and ultrapure water are mixed and stirred until homogeneous to obtain a cleaning agent for removing photoresist residue.

[0038] Example 3 A cleaning agent for removing photoresist residue comprises, by weight, the following raw materials: 12 parts sodium hydroxide, 4 parts monoethanolamine, 5 parts corrosion inhibitor, 3 parts fatty alcohol polyoxyethylene ether, 60 parts dimethyl sulfoxide, and 20 parts ultrapure water.

[0039] The corrosion inhibitor is a mixture of glycine derivative A, sodium phytate and sorbitol in a mass ratio of 1:0.6:0.6.

[0040] The preparation method of the cleaning agent used for removing photoresist residue in this embodiment is the same as in Embodiment 1.

[0041] Example 4 This embodiment provides a cleaning agent for removing photoresist residue and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that the mass ratio of glycine derivative A, sodium phytate and sorbitol in the corrosion inhibitor is 1:1:1.

[0042] Example 5 This embodiment provides a cleaning agent for removing photoresist residue and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that the corrosion inhibitor is a mixture of glycine derivative A and sodium phytate in a mass ratio of 1:0.5.

[0043] Example 6 This embodiment provides a cleaning agent for removing photoresist residue and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that the corrosion inhibitor is a mixture of glycine derivative A and sorbitol in a mass ratio of 1:0.5.

[0044] Example 7 This embodiment provides a cleaning agent for removing photoresist residue and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that the corrosion inhibitor is a mixture of sodium phytate and sorbitol in a mass ratio of 1:1.

[0045] Example 8 This embodiment provides a cleaning agent for removing photoresist residue and its preparation method. The specific implementation method is the same as in Embodiment 1, except that glycine derivative A is replaced by glycine derivative B in an equal amount.

[0046] Example 9 This embodiment provides a cleaning agent for removing photoresist residue and its preparation method. The specific implementation method is the same as that in Embodiment 1, except that glycine derivative A is replaced by glycine derivative C in an equal amount.

[0047] Example 10 This embodiment provides a cleaning agent for removing photoresist residue and its preparation method. The specific implementation method is the same as in Embodiment 1, except that glycine derivative A is replaced by glycine in an equal amount.

[0048] Performance testing The performance of the cleaning agents for removing photoresist residues in Examples 1-10 above was tested, and the test results are shown in Table 1.

[0049] Semiconductor chip sample used for testing: a 4cm × 4cm copper-plated Si wafer containing photoresist residue; Cleaning effect: The cleaning agents of Examples 1-10 were diluted 3 times with ultrapure water. Then, the semiconductor chip samples with photoresist to be cleaned were directly immersed in the cleaning solution at 40°C for 25 minutes. Then, they were rinsed with ultrapure water (resistance of at least 18MΩ at 25°C) and finally dried with high-purity nitrogen gas (volume purity greater than 99.999%). The photoresist cleaning was completed. The photoresist cleaning effect of the chip was observed under a microscope. Copper corrosion rate: The corrosion of metallic copper was precisely quantitatively tested using ICP-MS (inductively coupled plasma mass spectrometry). The specific test method is as follows: The semiconductor chip sample was immersed in a cleaning solution at 40°C for 30 minutes. Then, the concentration of metal ions in the cleaning solution was measured using ICP-MS, and the corrosion rate (Å / min, also known as "etching rate") was calculated. The corrosion rate of metallic copper by the cleaning solution was thus obtained. The lower the corrosion rate, the better the corrosion inhibition effect of the cleaning agent.

[0050] Table 1

[0051] As shown in Table 1, the cleaning agents in Examples 1-3 of this invention can thoroughly remove residual adhesive and have very low corrosion to the copper layer. Specifically, Example 4, which changed the ratio of the three substances in the corrosion inhibitor, and Examples 5-7, which replaced the corrosion inhibitor with any two of glycine derivative, sodium phytate, and sorbitol respectively, all resulted in varying degrees of decrease in the synergistic corrosion inhibition effect among the three substances, leading to an increase in the corrosiveness of the cleaning solution to copper. Examples 8-9, which changed the ratio of the two main substances in the glycine derivative, resulted in the formation of byproducts or incomplete reaction, both of which reduced the corrosion inhibition effect of the cleaning agent. Example 10, which used glycine to replace glycine derivative A in equal amounts, showed poor corrosion inhibition and also had a certain impact on the cleaning effect.

[0052] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A cleaning agent for removing photoresist residue, characterized in that, The cleaning agent comprises the following raw materials by weight: 8-12 parts inorganic alkali, 1-4 parts organic alkali, 2-5 parts corrosion inhibitor, 0.5-3 parts surfactant, 40-60 parts organic solvent, and 10-20 parts ultrapure water.

2. The cleaning agent for removing photoresist residue according to claim 1, characterized in that, The inorganic base is sodium hydroxide or potassium hydroxide.

3. The cleaning agent for removing photoresist residue according to claim 1, characterized in that, The organic base is any one of monoethanolamine, diethanolamine, or triethanolamine.

4. The cleaning agent for removing photoresist residue according to claim 1, characterized in that, The corrosion inhibitor is a mixture of glycine derivatives, sodium phytate, and sorbitol.

5. The cleaning agent for removing photoresist residue according to claim 4, characterized in that, The mass ratio of glycine derivative, sodium phytate and sorbitol in the corrosion inhibitor is 1:(0.4-0.6):(0.4-0.6).

6. The cleaning agent for removing photoresist residue according to claim 4, characterized in that, The preparation method of the glycine derivative includes the following steps: Glycine tert-butyl hydrochloride and sodium bicarbonate were added to acetonitrile, stirred, and then bromododecane and a catalyst were added. The mixture was refluxed, rotary evaporated, and then added to dichloromethane. After washing, the mixture was rotary evaporated and then added to anhydrous ethanol. The mixture was stirred, and then sodium ethoxide-ethanol mixed solution was added. The mixture was stirred, filtered, washed, and dried to obtain the glycine derivative.

7. The cleaning agent for removing photoresist residue according to claim 6, characterized in that, The molar ratio of glycine tert-butyl hydrochloride to bromododecane is 1:(0.9-1.1).

8. The cleaning agent for removing photoresist residue according to claim 1, characterized in that, The surfactant is a fatty alcohol polyoxyethylene ether.

9. The cleaning agent for removing photoresist residue according to claim 1, characterized in that, The organic solvent is dimethyl sulfoxide or N-methylpyrrolidone.

10. A method for preparing a cleaning agent for removing photoresist residues according to any one of claims 1-9, characterized in that, Includes the following steps: Inorganic alkali, organic alkali, corrosion inhibitor, surfactant, organic solvent and ultrapure water are mixed and stirred to obtain a cleaning agent for removing photoresist residue.

Images