High-efficiency stripping cleaning combined solution without hydroxylamine

Abstract

This invention relates to the field of cleaning solutions, specifically to a highly efficient hydroxylamine-free stripping and cleaning solution. The raw materials comprise the following components by mass fraction: 10-60% water, 10-50% water-soluble organic solvent (e.g., 10%-45%), 0.1-20% amine compound (e.g., 0.5%-10%), and 1-30% hydroxylamine substitute (e.g., 2%-20%), and a small amount of corrosion inhibitor, with the sum of the mass fractions of all components being 100%. The cleaning agent provided by this method exhibits good stability, prevents corrosion of Al metal during the cleaning process, has minimal negative impact on the conductivity of subsequent applications in device interconnects, and demonstrates good safety.

Description

Technical Field

[0001] This invention relates to the field of cleaning solutions, and in particular to a highly efficient hydroxylamine-free stripping and cleaning solution. Background Technology

[0002] In the development of semiconductor integrated circuits, large-scale, high-density, and miniaturization have become the trends. In their manufacturing process, the coating, exposure, development, and etching of photoresist layers are essential steps for patterning components. At the end of patterning (i.e., after photoresist coating, imaging, ion implantation, and dry etching), before proceeding to the next process step, any remaining material from the photoresist layer must be thoroughly removed. During dry etching or ion implantation, ion bombardment hardens the photoresist surface, forming a hard, carbonized shell that prevents the cleaning solution from cleaning the underlying substrate photoresist. Common cleaning methods involve oxygen plasma ashing processes to penetrate this hardened shell and remove the photoresist.

[0003] Typically, wet cleaning is required after the ashing process to remove remaining inorganic residues. This is especially true for sidewall polymers generated during the etching of aluminum, aluminum alloys, or silicon oxide, which are difficult to remove completely with traditional cleaning solutions. Hydroxylamine-based cleaning solutions offer good cleaning performance for these post-etching residues, but their cleaning lifespan is limited due to the instability of hydroxylamine. Adding catechol as a metal ion chelating agent and metal corrosion inhibitor usually achieves good results, but catechol is also highly toxic.

[0004] Hydroxylamine and its salts are important chemical raw materials, widely used in pharmaceutical synthesis, imaging technology, semiconductor cleaning, and other fields. Hydroxylamine can undergo thermal decomposition at ~15°C, breaking down into ammonia, nitrogen, water, nitrogen oxides, etc., thus exhibiting poor stability. Since the last century, the instability of hydroxylamine solutions has caused numerous explosions.

[0005] CN101146739A discloses a method for stabilizing hydroxylamine during the production of hydroxylamine free base, which involves adding the stabilizer ethylenediamine N,N-di(o-hydroxyphenylacetic acid), which can stabilize hydroxylamine under high temperature, high concentration, or with trace amounts of iron.

[0006] CN101910057A discloses a method for improving the stability of hydroxylamine solutions by adding a methylamine oxime, wherein the methylamine oxime compound is prepared by reacting hydroxylamine with a nitrile compound.

[0007] CN101093363A discloses a cleaning solution for removing photoresist from integrated circuits, comprising a composite chelating agent, hydrogen peroxide, and deionized water, with the following weight percentages: composite chelating agent 5-10%; hydrogen peroxide 3-8%; and deionized water as the balance. The chelating agent used in this cleaning solution has a strong complexing ability for metal ions, thus completely removing them without causing metal ion contamination.

[0008] CN107765514B discloses a stable hydroxylamine-containing solution using cyclodextrin-modified alkylene glycol alkyl ether compounds as additives. The stability of hydroxylamine in this solution is significantly improved, overcoming the shortcomings of existing hydroxylamine-containing cleaning solutions, such as poor cleaning performance and corrosion of metals (e.g., aluminum) during deionized water rinsing. CN107765514B provides a hydroxylamine-containing cleaning solution, its preparation method, and its applications. The hydroxylamine cleaning solution containing dextrin-modified alkylene glycol alkyl ether compounds surpasses the cleaning capabilities of traditional hydroxylamine-based cleaning agents, while exhibiting lower corrosion rates on both metals and non-metals.

[0009] CN115595217A discloses a method for encapsulating hydroxylamine molecules with cucurbituril and its derivatives, thereby improving the stability of hydroxylamine and preventing direct contact between hydroxylamine molecules and alkaline substances and trace metal ions, thus extending the shelf life of hydroxylamine-containing cleaning solutions. A "claw-shaped" chelating agent enhances the complexation with metal ions, further improving the shelf life and service life of the hydroxylamine-containing cleaning solution. This forms a stable hydroxylamine-containing solution with significantly improved stability. It avoids the decomposition of hydroxylamine due to metal ion catalysis and also prevents decomposition caused by high temperature and alkalinity. This solution can be applied in the semiconductor field to maximize the stability of semiconductor cleaning solutions.

[0010] Description of the prior art: In view of the problem of poor stability of traditional hydroxylamine-containing solutions, a cleaning formulation solution containing or without hydroxylamine is proposed. In this solution, the role of hydroxylamine is replaced by other reducing agents, which can avoid the problem of explosion caused by the decomposition of hydroxylamine due to metal ion catalysis during the production process, and achieve the same effect as hydroxylamine. This solution can be applied in the semiconductor field, greatly improving the accessibility of semiconductor cleaning solutions.

[0011] While these known products or patents can effectively clean plasma etching residues, they also impose burdens on manufacturing processes and environmental remediation. Therefore, the development of cleaning solutions using hydroxylamine alternatives is crucial. Summary of the Invention

[0012] (a) Technical problems to be solved

[0013] The technical problem this invention aims to solve is to overcome the shortcomings of existing hydroxylamine-containing cleaning solutions, such as poor cleaning effect, easy decomposition of hydroxylamine, and safety concerns in production. This invention provides a cleaning solution containing a hydroxylamine substitute, its preparation method, and its application. The hydroxylamine substitute cleaning solution of this invention has the same cleaning ability as traditional hydroxylamine-based cleaning agents, while exhibiting a lower corrosion rate on both metals and non-metals.

[0014] (II) Technical Solution

[0015] The present invention provides a cleaning solution containing a hydroxylamine substitute, which is prepared from the following raw materials, wherein the raw materials comprise the following components in the following mass fractions: 10-60% water, 10-50% water-soluble organic solvent (e.g., 10%-45%), 0.1-20% amine compound (e.g., 0.5%-10%), and 1-30% hydroxylamine substitute (e.g., 2%-20%), and a small amount of corrosion inhibitor, wherein the sum of the mass fractions of each component is 100%.

[0016] Furthermore, the water-soluble solvent is preferably a common organic solvent, preferably N,N-dimethylformamide, N,N-diethylacetamide, N-formylmorpholine, N-methyl-2-pyrrolidone, sulfolane, dimethyl sulfoxide, hexamethylphosphoric triamine, or 1,3-dimethyl-2-imidazolinone.

[0017] Furthermore, the amine compound can be a conventional amine compound in the art, preferably an aliphatic amine compound. The aliphatic amine compound is preferably one or more of the following: 2-ethylhexylamine, diethylamine, n-butylamine, tert-butylamine, n-hexylamine, cyclohexylamine, n-octylamine, dimethylformamide, monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, 2-diethylaminoethanol, ethyldiethanolamine and diethylene glycolamine, N-methyl-N-butylamine and n-dodecylamine.

[0018] Furthermore, the hydroxylamine substitute is preferably a compound with strong reducing properties, one or more of hydrazine hydrate, phenylhydrazine, thiohydrazine, oxalic acid dihydrazine, oxalazine, isoniazid, acetaldehyde oxime, acetone oxime, N-isopropylhydroxylamine, and hydroxyurea.

[0019] Furthermore, the corrosion inhibitor is selected from antistatic corrosion inhibitors.

[0020] Furthermore, the antistatic corrosion inhibitor is prepared according to the following method:

[0021] S1: According to the mass fractions, add 0.05-0.6 parts of 1-aminopropyl-3-methylimidazolium bromide, 20-30 parts of allyl epoxy polyether, 2-6 parts of diethanolamine, and 300-420 parts of toluene to a high-pressure reactor and stir for 30-60 minutes.

[0022] S2: Add 17-23 parts of 2,5-dimercaptohydroquinone and 0.4-1 parts of benzoyl peroxide. Stir and react for 2-5 hours, then remove toluene by vacuum distillation to obtain the antistatic corrosion inhibitor.

[0023] Furthermore, the allyl epoxy polyether is selected from APE600 or APE1000.

[0024] Furthermore, the reaction temperature during the preparation of the antistatic corrosion inhibitor is 60-80℃.

[0025] This invention focuses on protecting the hydroxylamine substitute. As a reducing agent, it can decompose etching residues by forming a strong reducing agent. The combination of the reducing agent and the corrosion inhibitor can control metal corrosion, preventing the substrate metal from being etched during the cleaning process.

[0026] (III) Technical Mechanism

[0027] The solvent selection of the present invention is a water-soluble solvent that enables the solubilization of metal cations to enhance wetting and solubilization of residues and organic matter, such as N,N-dimethylformamide, N,N-diethylacetamide, N-formylmorpholine, N-methyl-2-pyrrolidone, sulfolane, dimethyl sulfoxide, hexamethylphosphoric triamine, and 1,3-dimethyl-2-imidazolinone.

[0028] Organic amine compounds provide an alkaline environment that facilitates the breakdown of post-etching residues and undercut cleaning, such as one or more of 2-ethylhexylamine, diethylamine, n-butylamine, tert-butylamine, n-hexylamine, cyclohexylamine, n-octylamine, dimethylformamide, monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, 2-diethylaminoethanol, ethyl diethanolamine and diethylene glycolamine, N-methyl-N-butylamine and n-dodecylamine.

[0029] Hydroxylamine substitutes have strong reducing and reactive properties, such as hydrazine hydrate, phenylhydrazine, thiohydrazine, oxalic acid dihydrazine, oxalazine, isoniazid, acetaldehyde oxime, acetone oxime, N-isopropylhydroxylamine, and hydroxyurea.

[0030] 1-Aminopropyl-3-methylimidazolium bromide and allyl epoxy polyether first undergo an amino addition reaction to obtain product 1; excess allyl epoxy polyether then undergoes a mercapto addition reaction with 2,5-dimercaptohydroquinone to obtain product 2; then, the unsaturated bonds are removed by polymerization.

[0031] (iv) Beneficial effects

[0032] The present invention provides a highly efficient hydroxylamine-free stripping and cleaning solution, which, compared with the prior art, has the following significant advantages:

[0033] (1) This formula has simple ingredients, good stability, and can prevent Al metal from corroding during the cleaning process;

[0034] (2) The formulation of this invention can be used to remove etched and ashed organic and inorganic residues, as well as polymer residues, from semiconductor substrates at high temperatures with minimal corrosion (e.g., low metal etching rates). Therefore, it has minimal negative impact on the conductivity of subsequent applications in device interconnects.

[0035] (3) The formulation raw material preparation process of the present invention is simple, the purification process of hydroxylamine substitute is simple, and the safety is good. Detailed Implementation

[0036] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0037] Example 1

[0038] A cleaning solution containing a hydroxylamine substitute is prepared from the following raw materials, which include the following components in mass fractions: 60% water, 20% water-soluble organic solvent, 10% amine compound, 10% hydroxylamine substitute, and a small amount of corrosion inhibitor, the sum of the mass fractions of each component being 100%.

[0039] The water-soluble solvent is N,N-dimethylformamide.

[0040] The aliphatic amine compound is 2-ethylhexylamine.

[0041] The hydroxylamine substitute is hydrazine hydrate.

[0042] The corrosion inhibitor is selected from antistatic corrosion inhibitors.

[0043] The antistatic corrosion inhibitor is prepared according to the following method:

[0044] S1: Add 0.1g of 1-aminopropyl-3-methylimidazolium bromide, 20g of allyl epoxy polyether, 2g of diethanolamine, and 300g of toluene to a high-pressure reactor and stir for 30 minutes.

[0045] S2: Add 17g of 2,5-dimercaptohydroquinone and 0.4g of benzoyl peroxide, stir and react for 2h, remove toluene by vacuum distillation, and the antistatic corrosion inhibitor is obtained.

[0046] The allyl epoxy polyether is selected from APE600.

[0047] The reaction temperature during the preparation of the antistatic corrosion inhibitor is 60℃.

[0048] Example 2

[0049] A cleaning solution containing a hydroxylamine substitute is prepared from the following raw materials, which include the following components in mass fractions: 40% water, 30% water-soluble organic solvent, 20% amine compound, 10% hydroxylamine substitute, and a small amount of corrosion inhibitor, the sum of the mass fractions of each component being 100%.

[0050] The water-soluble solvent is N,N-diethylacetamide.

[0051] The aliphatic amine compound is n-butylamine.

[0052] The hydroxylamine substitute is oxalic acid dihydrazide.

[0053] The corrosion inhibitor is selected from antistatic corrosion inhibitors.

[0054] The antistatic corrosion inhibitor is prepared according to the following method:

[0055] S1: Add 0.3g of 1-aminopropyl-3-methylimidazolium bromide, 23g of allyl epoxy polyether, 3g of diethanolamine, and 330g of toluene to a high-pressure reactor and stir for 35 minutes.

[0056] S2: Add 19g of 2,5-dimercaptohydroquinone and 0.6g of benzoyl peroxide, stir and react for 3h, remove toluene by vacuum distillation, and the antistatic corrosion inhibitor is obtained.

[0057] The allyl epoxy polyether is selected from APE600.

[0058] The reaction temperature during the preparation of the antistatic corrosion inhibitor is 65℃.

[0059] Example 3

[0060] A cleaning solution containing a hydroxylamine substitute is prepared from the following raw materials, which include the following components in mass fractions: 40% water, 35% water-soluble organic solvent, 15% amine compound, 10% hydroxylamine substitute, and a small amount of corrosion inhibitor, the sum of the mass fractions of each component being 100%.

[0061] The water-soluble solvent is sulfolane.

[0062] The aliphatic amine compound is 2-diethylaminoethanol.

[0063] The hydroxylamine substitute is acetone oxime.

[0064] The corrosion inhibitor is selected from antistatic corrosion inhibitors.

[0065] The antistatic corrosion inhibitor is prepared according to the following method:

[0066] S1: Add 0.45g of 1-aminopropyl-3-methylimidazolium bromide, 27g of allyl epoxy polyether, 5g of diethanolamine, and 390g of toluene to a high-pressure reactor and stir for 50 minutes.

[0067] S2: Add 21g of 2,5-dimercaptohydroquinone and 0.8g of benzoyl peroxide, stir and react for 4h, remove toluene by vacuum distillation, and the antistatic corrosion inhibitor is obtained.

[0068] The allyl epoxy polyether is selected from APE1000.

[0069] The reaction temperature during the preparation of the antistatic corrosion inhibitor is 75℃.

[0070] Example 4

[0071] A cleaning solution containing a hydroxylamine substitute is prepared from the following raw materials, which include the following components in mass fractions: 25% water, 45% water-soluble organic solvent, 15% amine compound, 15% hydroxylamine substitute, and a small amount of corrosion inhibitor, the sum of the mass fractions of each component being 100%.

[0072] The water-soluble solvent is 1,3-dimethyl-2-imidazolinone.

[0073] The aliphatic amine compound is N-methyl-N-butylamine.

[0074] The hydroxylamine substitute water is hydroxyurea.

[0075] The corrosion inhibitor is selected from antistatic corrosion inhibitors.

[0076] The antistatic corrosion inhibitor is prepared according to the following method:

[0077] S1: Add 0.6g of 1-aminopropyl-3-methylimidazolium bromide, 30g of allyl epoxy polyether, 6g of diethanolamine and 420g of toluene to a high-pressure reactor and stir for 60 minutes.

[0078] S2: Add 23g of 2,5-dimercaptohydroquinone and 1g of benzoyl peroxide, stir and react for 5h, remove toluene by vacuum distillation, and the antistatic corrosion inhibitor is obtained.

[0079] The allyl epoxy polyether is selected from APE1000.

[0080] The reaction temperature during the preparation of the antistatic corrosion inhibitor is 80℃.

[0081] Comparative Example 1

[0082] A cleaning solution containing a hydroxylamine substitute is prepared from the following raw materials, which include the following components in mass fractions: 60% water, 20% water-soluble organic solvent, 10% amine compound, 10% hydroxylamine substitute, and a small amount of corrosion inhibitor, the sum of the mass fractions of each component being 100%.

[0083] The water-soluble solvent is N,N-dimethylformamide.

[0084] The aliphatic amine compound is 2-ethylhexylamine.

[0085] The hydroxylamine substitute is hydrazine hydrate.

[0086] The corrosion inhibitor is selected from pyrogallol.

[0087] Comparative Example 2

[0088] A cleaning solution containing a hydroxylamine substitute is prepared from the following raw materials, which include the following components in mass fractions: 60% water, 20% water-soluble organic solvent, 10% amine compound, 10% hydroxylamine substitute, and a small amount of corrosion inhibitor, the sum of the mass fractions of each component being 100%.

[0089] The water-soluble solvent is N,N-dimethylformamide.

[0090] The aliphatic amine compound is 2-ethylhexylamine.

[0091] The hydroxylamine substitute is hydrazine hydrate.

[0092] The corrosion inhibitor is selected from antistatic corrosion inhibitors.

[0093] The antistatic corrosion inhibitor is prepared according to the following method:

[0094] S1: Add 20g of allyl epoxy polyether, 2g of diethanolamine, and 300g of toluene to a high-pressure reactor and stir for 30 minutes.

[0095] S2: Add 17g of 2,5-dimercaptohydroquinone and 0.4g of benzoyl peroxide, stir and react for 2h, remove toluene by vacuum distillation, and the antistatic corrosion inhibitor is obtained.

[0096] The allyl epoxy polyether is selected from APE600.

[0097] The reaction temperature during the preparation of the antistatic corrosion inhibitor is 60℃.

[0098] Comparative Example 3

[0099] A cleaning solution containing a hydroxylamine substitute is prepared from the following raw materials, which include the following components in mass fractions: 60% water, 20% water-soluble organic solvent, 10% amine compound, 10% hydroxylamine substitute, and a small amount of corrosion inhibitor, the sum of the mass fractions of each component being 100%.

[0100] The water-soluble solvent is N,N-dimethylformamide.

[0101] The aliphatic amine compound is 2-ethylhexylamine.

[0102] The hydroxylamine substitute is hydrazine hydrate.

[0103] The corrosion inhibitor is selected from antistatic corrosion inhibitors.

[0104] The antistatic corrosion inhibitor is prepared according to the following method:

[0105] S1: Add 0.1g of 1-aminopropyl-3-methylimidazolium bromide, 20g of allyl epoxy polyether, 2g of diethanolamine, and 300g of toluene to a high-pressure reactor and stir for 30 minutes.

[0106] S2: Add 17g of 2,5-dimercaptohydroquinone, stir and react for 2h, remove toluene by vacuum distillation, and the antistatic corrosion inhibitor is obtained.

[0107] The allyl epoxy polyether is selected from APE600.

[0108] The reaction temperature during the preparation of the antistatic corrosion inhibitor is 60℃.

[0109] Example Evaluation:

[0110] The etching rates of metallic aluminum and non-metallic materials (plasma-enhanced silica (PETEOS)) were tested, and wafers after plasma etching and ashing were cleaned using three different types of materials.

[0111] I. Test method for metal corrosion rate of cleaning fluid:

[0112] 1. Use a Napson four-point probe to test the initial resistance (Rs1) of a 4×4cm blank aluminum silicon wafer;

[0113] 2. Immerse the 4×4cm blank aluminum silicon wafer in a solution that has been preheated to the set temperature for 60 minutes;

[0114] 3. Remove the 4×4cm blank aluminum silicon wafer, rinse it, dry it with high-purity nitrogen, and then use a Napson four-point probe to test the resistance value (Rs2) of the 4×4cm blank aluminum silicon wafer.

[0115] 4. Input the above resistance value and immersion time into a suitable program to calculate its corrosion rate.

[0116] II. Test method for non-metallic corrosion rate of cleaning fluid:

[0117] 1. The thickness (T1) of a 4×4cm PETEOS silicon wafer was measured using a Nanospec 6100 thickness gauge;

[0118] 2. Immerse the 4×4cm PETEOS silicon wafer in a solution that has been preheated to the set temperature for 60 minutes;

[0119] 3. Remove the 4×4cm PETEOS silicon wafer, rinse it, dry it with high-purity nitrogen, and then use a Nanospec6100 thickness gauge to measure the thickness (T2) of the 4×4cm PETEOS silicon wafer.

[0120] 4. Input the above thickness value and immersion time into a suitable program to calculate its corrosion rate.

[0121] III. Wafer Cleaning Methods

[0122] 1. Place the wafer to be cleaned into a solution that has been preheated to the set temperature;

[0123] 2. Soak the wafer according to the principle of soaking the metal wire for 20 minutes and the channels and metal pads for 30 minutes;

[0124] 3. After the soaking time is up, remove the wafer, rinse it, dry it with high-purity nitrogen, and send it for SEM testing.

[0125] Table 1. Test results of Examples 1-4 and Comparative Examples 1-3

[0126]

[0127] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A highly efficient hydroxylamine-free stripping and cleaning solution, prepared from the following raw materials, wherein the raw materials consist of the following components in mass fractions: The composition consists of 10-60% water, 10-50% water-soluble organic solvent, 0.1-20% amine compound, 1-30% hydroxylamine substitute, and a small amount of corrosion inhibitor, with the sum of the mass fractions of all components being 100%. The hydroxylamine substitute is selected from one or more of hydrazine hydrate, phenylhydrazine, thiohydrazine, oxalic acid dihydrazine, lansohydrazine, isoniazid, acetaldehyde oxime, acetone oxime, and hydroxyurea; The corrosion inhibitor is an antistatic corrosion inhibitor; The antistatic corrosion inhibitor is prepared according to the following method: S1: According to the mass fractions, add 0.05-0.6 parts of 1-aminopropyl-3-methylimidazolium bromide, 20-30 parts of allyl epoxy polyether, 2-6 parts of diethanolamine, and 300-420 parts of toluene to a high-pressure reactor and stir for 30-60 minutes. S2: Add 17-23 parts of 2,5-dimercaptohydroquinone and 0.4-1 parts of benzoyl peroxide. Stir and react for 2-5 hours, then remove toluene by vacuum distillation to obtain the antistatic corrosion inhibitor. The reaction temperature during the preparation of the antistatic corrosion inhibitor is 60-80℃.

2. The high-efficiency hydroxylamine-free stripping and cleaning solution according to claim 1, characterized in that: The water-soluble organic solvent is selected from N,N-dimethylformamide, N,N-diethylacetamide, N-formylmorpholine, N-methyl-2-pyrrolidone, sulfolane, dimethyl sulfoxide, hexamethylphosphoric triamine, or 1,3-dimethyl-2-imidazolinone.

3. The high-efficiency hydroxylamine-free stripping and cleaning solution according to claim 1, characterized in that: The amine compound is an aliphatic amine compound.

4. The high-efficiency hydroxylamine-free stripping and cleaning solution according to claim 3, characterized in that: The aliphatic amine compound is selected from one or more of 2-ethylhexylamine, diethylamine, n-butylamine, tert-butylamine, n-hexylamine, cyclohexylamine, n-octylamine, dimethylformamide, monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, 2-diethylaminoethanol, ethyl diethanolamine and diethylene glycolamine, N-methyl-N-butylamine and n-dodecylamine.

5. The high-efficiency hydroxylamine-free stripping and cleaning solution according to claim 1, characterized in that: The allyl epoxy polyether is selected from APE600 or APE1000.

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