Semiconductor wafer amine washing post-cleaning liquid and preparation method and application thereof

Abstract

The invention relates to a cleaning solution for semiconductor wafers after amine washing, which comprises the following components in parts by weight: 50-80 parts of environment-friendly organic solvent; 0.5 to 3 parts of an amino alcohol corrosion inhibitor; 1-5 parts of a polyhydroxy corrosion inhibitor; and 10 to 20 parts of ultrapure water. The invention further discloses a preparation method and application of the cleaning fluid. The compound corrosion inhibitor is composed of an amino alcohol corrosion inhibitor and a polyhydroxy corrosion inhibitor, and has N and O polar groups with large electronegativity and C and H non-polar groups, on one hand, N and O with large electronegativity in the polar groups contain lone pair electrons, and the lone pair electrons interact with metal, so that the metal corrosion resistance is improved; therefore, a protective barrier is formed between metal and alloy surfaces and a corrosive medium, and the purpose of retarding metal corrosion is achieved. And on the other hand, the non-polar groups are closely arranged on the metal surface to form a hydrophobic protective film, so that transfer of charges or substances related to corrosion reaction is hindered, and the corrosion reaction is inhibited.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor cleaning technology, and in particular relates to a cleaning solution for semiconductor wafers after amine washing, and a preparation method and application thereof. Background Art

[0002] In the back-end of line fabrication of microelectronic components on aluminum (Al) or aluminum / copper (Cu) metallized substrates, an essential step is depositing a photoresist film on the chip substrate. The photoresist then acts as a mask to form a circuit pattern. After baking and developing, the resulting pattern is transferred to the underlying substrate material (electrolyte or metal layer) via a reactive plasma etching gas. During the plasma etching process, the interaction between the plasma gas, the etched substrate material, and the photoresist forms etch residues on or around the sidewalls of the etched substrate, also causing crosslinking of the photoresist mask material. After etching is complete, the photoresist mask and etch residues must be removed from the patterned wafer to facilitate the next step.

[0003] Currently, the mainstream cleaning step for Al or Al(Cu) metallized substrates after etching and removing the photoresist shield (ashing) is to use organic amine cleaning solutions. The advantage of organic amine cleaning solutions is that they can effectively remove various insoluble inorganic and organic residues. However, after etching and ashing, directly rinsing the patterned wafer with water after the cleaning solution treatment can easily cause corrosion to the metal substrate on the patterned wafer surface.

[0004] Therefore, based on the current problem of metal corrosion caused by direct contact with water after wafers are cleaned with organic amine wafer cleaning fluid, there is an urgent need to develop a wafer cleaning fluid for the next process after the organic amine wafer cleaning fluid, which has a lower corrosion rate on metals, especially aluminum. Summary of the Invention

[0005] The technical problem solved by the present invention is that the corrosion rate of metals, especially aluminum, is relatively high when washing with water directly after cleaning with an organic amine cleaning solution.

[0006] In view of the technical problems existing in the prior art, the present invention provides a cleaning solution for semiconductor wafers after amine washing. After cleaning with an organic amine cleaning solution, the cleaning solution of the present invention is first used for cleaning and then rinsed with water to protect the wafer surface and reduce corrosion to the metal.

[0007] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "consisting of..." etc. and similar meanings.

[0008] In order to solve the above-mentioned technical problems, the present invention adopts the following solutions: A cleaning solution for semiconductor wafers after amine washing, characterized in that it comprises the following components, calculated in parts by weight: 50-80 parts of environmentally friendly organic solvent; 0.5-3 parts of amino alcohol corrosion inhibitor; 1-5 parts of polyhydroxy corrosion inhibitor; 10-20 parts of ultrapure water; The environmentally friendly organic solvent is one or more of gamma-valerolactone, dihydrolevulinone, propylene carbonate, 1-butyl-2-pyrrolidone and 5-(dimethylamino)-2-methyl-5-oxopentanoic acid methyl ester.

[0009] Furthermore, the amino alcohol corrosion inhibitor is one or more of L-phenylglycinol, 3-amino-3-phenylpropanol, and (S)-(+)-2-tert-butylamino-1-phenylethanol.

[0010] Furthermore, the polyhydroxy corrosion inhibitor is a hydroxyl-containing plant extract.

[0011] Furthermore, the molecular weight of the polyhydroxy corrosion inhibitor is less than 400.

[0012] Furthermore, the polyhydroxy corrosion inhibitor is one or more of 3-hydroxytyrosol, aloe-emodin, and cannabidiol.

[0013] Furthermore, the mass ratio of the amino alcohol corrosion inhibitor to the polyhydroxy corrosion inhibitor is (0.5-3): (1-5).

[0014] Furthermore, the mass ratio of the amino alcohol corrosion inhibitor to the polyhydroxy corrosion inhibitor is 3:2.

[0015] Furthermore, the ultrapure water is deionized water with a resistance of ≥18 MΩ.

[0016] The present invention also discloses a method for preparing a cleaning solution for semiconductor wafers after amine washing, which is characterized by comprising the following steps: Step 1: Weigh each component in its respective amount; Step 2: All components are mixed and stirred until completely dissolved, and then filtered after complete dissolution to obtain the semiconductor wafer post-amine washing cleaning solution.

[0017] Furthermore, the filtration is performed using filter elements of 0.5 μm, 0.1 μm, and 0.05 μm in sequence.

[0018] The invention also discloses a use of a cleaning solution for cleaning semiconductor wafers after amine washing.

[0019] The present invention also discloses a method for using a cleaning solution for semiconductor wafers after amine washing, which is characterized by comprising the following steps: Step 1: soaking the semiconductor wafer cleaned with an organic amine cleaning solution in the semiconductor wafer post-amine cleaning solution for 1-5 minutes to obtain a soaked semiconductor wafer; Step 2: Rinse the soaked semiconductor wafer with deionized water for 1-5 minutes, and dry the chip with IPA / N2 after soaking, thus completing the semiconductor wafer processing.

[0020] In the cleaning liquid system of the present invention, in order to further optimize the effect, each component can be optimized, 70-80 parts of environmentally friendly organic solvent; 1.5-3 parts of amino alcohol corrosion inhibitor; 1-2 parts of polyhydroxy corrosion inhibitor; 15-20 parts of ultrapure water.

[0021] In the present invention, the environmentally friendly organic solvent is methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate.

[0022] In the present invention, the amino alcohol corrosion inhibitor is L-phenylglycinol.

[0023] In the present invention, the polyhydroxy corrosion inhibitor is 3-hydroxytyrosol.

[0024] In the present invention, the soaking time in step 1 of the method for using the cleaning solution is 3-5 minutes; and the soaking temperature is 20-25°C.

[0025] In the present invention, the rinsing time in step 2 of the method for using the cleaning solution is 3-5 minutes.

[0026] The present invention provides a semiconductor wafer amine cleaning solution and a preparation method and application thereof, which have the following beneficial effects: 1. The present invention adopts amino alcohol corrosion inhibitor and polyhydroxy corrosion inhibitor to form a composite corrosion inhibitor, which has polar groups of N and O with high electronegativity and non-polar groups of C and H. On the one hand, the polar groups of N and O with high electronegativity contain lone pairs of electrons, and the lone pairs of electrons interact with the metal, thereby forming a protective barrier between the metal and alloy surface and the corrosive medium, thereby achieving the purpose of slowing down metal corrosion; on the other hand, the non-polar groups are closely arranged on the metal surface to form a hydrophobic protective film that hinders the transfer of charges or substances related to the corrosion reaction, thereby inhibiting the corrosion reaction.

[0027] 2. The present invention uses an environmentally friendly organic solvent and ultrapure water to form a composite solvent system, which can enhance the wetting of the chip during the subsequent deionized water rinse step, thereby saving costs.

[0028] 3. The present invention adds organic solvents and water to the cleaning liquid, which can be well compatible with the organic amine cleaning liquid of the previous process and the deionized water of the subsequent process, so that the cleaning liquid has good compatibility. On the basis of meeting the cleaning requirements of the organic amine cleaning liquid, it avoids direct contact between the deionized water and the wafer, thereby avoiding metal corrosion.

[0029] Therefore, the wafer cleaning solution of the present invention has very good application prospects and large-scale industrial promotion potential in the field of semiconductor wafer cleaning. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to specific embodiments: Table 1 Examples 1-6

[0031] Table 2 Comparative Examples 1-6

[0032] Table 3 Test data

[0033] The method for preparing a cleaning solution for semiconductor wafers after amine washing according to the present invention comprises the following steps: Step 1: Weigh each component in its respective amount; Step 2: Mix and stir the components until they are completely dissolved. After they are completely dissolved, filter them in sequence using 0.5 μm, 0.1 μm, and 0.05 μm filter cartridges to obtain the semiconductor wafer post-amine washing cleaning solution.

[0034] The method for using the cleaning solution for semiconductor wafers after amine washing of the present invention comprises the following steps: Step 1: soaking the semiconductor wafer cleaned with the organic amine cleaning solution in the cleaning solution of the present invention for 1-5 minutes at a temperature of 20-25° C. to obtain a soaked semiconductor wafer; Step 2: Rinse the soaked semiconductor wafer with deionized water for 1-5 minutes, and dry the chip with IPA / N2 after soaking, thus completing the semiconductor wafer processing.

[0035] About performance testing and description: Performance 1 The test method for metal corrosion is: A four-probe resistance meter was used to test the corrosion performance of different cleaning solutions on metals. The specific test method was as follows: an 8-inch wafer plated with an Al (containing a small amount of Cu) layer was immersed in the cleaning solution at 25°C for 5 minutes. The difference in film thickness before and after the wafer was measured using a four-probe resistance meter, and the corrosion rate (Å / min, also known as "etching rate") was calculated, thereby examining the corrosion rate of different cleaning solutions on metals.

[0036] In terms of technology, aluminum process wafers will use Al (doped with a small amount of copper) to improve the electromigration capability. The content of doped copper is generally between 0.5% and 5%.

[0037] Analysis of the test results: Based on Table 3, it can be seen that the present invention adopts a compound of amino alcohol corrosion inhibitor and polyhydroxy corrosion inhibitor. On the one hand, the lone pair electrons interact with the metal, and on the other hand, the compound corrosion inhibitor is closely arranged on the metal surface, thereby having a good slow-release effect on Al. However, due to the lack of L-phenylglycinol in Comparative Example 1 and the lack of 3-hydroxytyrosol in Comparative Example 2, the single corrosion inhibitor was not tightly arranged on the metal surface, resulting in higher corrosion of Al by the cleaning solution; Comparative Example 3 uses phlorizin and L-phenylglycinol as a composite corrosion inhibitor. Although phlorizin is also a polyhydroxy substance, its molecular weight and molecular structure are relatively large. Compared with the embodiment, L-phenylglycinol as a composite corrosion inhibitor cannot be arranged closely enough on the metal surface, resulting in slightly higher corrosion of Al by the cleaning solution. Comparative Example 4 uses N-methylethanolamine and 3-hydroxytyrosol as a composite corrosion inhibitor. Since the amino group in N-methylethanolamine is replaced by an alkyl group, the effect of -NH- is less than that of -NH2, resulting in slightly higher corrosion of Al by the cleaning solution. Comparative Example 5 uses o-aminobenzyl alcohol and glucose as a composite corrosion inhibitor. Due to the high toxicity of o-aminobenzyl alcohol, the toxicity of the composite cleaning solution is potentially harmful to the environment and personnel; at the same time, the corrosion rate of Al metal increases.

[0038] In Comparative Example 6, when only ultrapure water was used for cleaning, the Al metal corrosion rate reached 4.96 Å / min.

[0039] The present invention has been described above by way of example in conjunction with the embodiments. It is obvious that the implementation of the present invention is not limited to the above-mentioned methods. As long as various improvements are made using the method concepts and technical solutions of the present invention, or the concepts and technical solutions of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A semiconductor wafer cleaning solution after amine washing, characterized in that: Calculated by weight, it includes the following components: 50-80 parts of environmentally friendly organic solvent; 0.5-3 parts of amino alcohol corrosion inhibitor; 1-5 parts of polyhydroxy corrosion inhibitor; 10-20 parts of ultrapure water; The environmentally friendly organic solvent is one or more of gamma-valerolactone, dihydrolevulinone, propylene carbonate, 1-butyl-2-pyrrolidone and 5-(dimethylamino)-2-methyl-5-oxopentanoic acid methyl ester.

2. The semiconductor wafer cleaning solution after amine washing according to claim 1, characterized in that: The amino alcohol corrosion inhibitor is one or more of L-phenylglycinol, 3-amino-3-phenylpropanol, and (S)-(+)-2-tert-butylamino-1-phenylethanol.

3. The semiconductor wafer cleaning solution after amine washing according to claim 1, characterized in that: The polyhydroxy corrosion inhibitor is a plant extract containing hydroxyl groups.

4. The semiconductor wafer cleaning solution after amine washing according to claim 1 or 3, characterized in that: The polyhydroxy corrosion inhibitor is one or more of 3-hydroxytyrosol, aloe-emodin, and cannabidiol.

5. The semiconductor wafer cleaning solution after amine washing according to claim 1, characterized in that: The mass ratio of the amino alcohol corrosion inhibitor to the polyhydroxy corrosion inhibitor is (0.5-3): (1-5).

6. A method for preparing a cleaning solution for semiconductor wafers after amine washing according to any one of claims 1 to 5, characterized in that The following steps are involved: Step 1: Weigh each component in its respective amount; Step 2: All components are mixed and stirred until completely dissolved, and then filtered after complete dissolution to obtain the semiconductor wafer post-amine washing cleaning solution.

7. Use of the semiconductor wafer post-amine washing cleaning solution according to any one of claims 1 to 5 in cleaning semiconductor wafers.

8. A method for using the semiconductor wafer cleaning solution after amine washing according to claim 7, characterized in that The following steps are involved: Step 1: soaking the semiconductor wafer cleaned with an organic amine cleaning solution in the semiconductor wafer post-amine cleaning solution for 1-5 minutes to obtain a soaked semiconductor wafer; Step 2: Rinse the soaked semiconductor wafer with deionized water for 1-5 minutes, and dry the semiconductor wafer with IPA / N2 after soaking, thereby completing the semiconductor wafer processing.

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