A silver stripping solution and its preparation method and application

Abstract

The present invention belongs to the technical field of stripping liquid, and in particular to a silver stripping liquid and its preparation method and application. The silver stripping liquid described in this patent includes the following components by weight: 0.1-1 parts of imidazole reagents, 15-25 parts of organic amines, 75-85 parts of organic solvents, and 1-10 parts of corrosion inhibitors. The silver stripping liquid product described in the present invention takes silver-based wafers as the target, and can effectively remove the surface photoresist without corrosion. During the experiment, the silver stripping liquid described in the present invention can effectively remove the surface photoresist of the silver-based wafer, with almost no residual glue; there are no silver particles in the scribe path, and there is no color difference after the wafer is baked, and the product yield is high; and more than 750 wafers can be cleaned during use, and the product has a long service life. And the product raw materials avoid the use of hazardous chemicals such as dimethyl sulfoxide, and implement the principle of green, non-toxic and sustainable development of products.

Description

Technical Field

[0001] The invention belongs to the technical field of stripping solutions, and in particular relates to a silver stripping solution and a preparation method and application thereof. Background Art

[0002] At present, silver-based wafers are widely used in the semiconductor industry. Silver-based wafers generally contain three layers, from top to bottom, silver, nickel, and titanium. The thickness of the photoresist layer is After the photoresist coated on the surface of the wafer is etched or ion implanted, the photoresist needs to be removed from the surface of the wafer. This step requires the use of a stripping liquid product. At present, the stripping liquid used in the prior art has the following components: 60%-62% ethers and 36%-40% amines. This stripping liquid has good degumming ability in the industrial production process, but after cleaning 300 wafers, this stripping liquid will show corrosiveness to the wafers, causing a large number of silver particles in the scribe lanes, and the color difference rate of the wafers after baking is high, affecting the product yield. In view of this situation, the silver-based wafer is used as the research object, hoping to formulate a new product that can remove the photoresist on the silver substrate after reacting with the photoresist, and has no corrosive effect on the substrate, and the wafers after baking have no color difference, so as to improve the qualified rate of products in industrial production. Summary of the invention

[0003] In order to solve the problems in the above-mentioned prior art that the stripping solution is too corrosive to wafers in the later stage, a large number of silver particles exist in the dicing lanes, and the color difference rate of the wafers after baking is high, which affects the product yield, the present invention provides a silver stripping solution. By re-formulating the product formula, adding imidazole reagents and the like as a photoresist stripping solution composition, using ethers as organic solvents, and adding amine reagents to adjust the properties of the solution, it is possible to ensure that the photoresist is effectively removed while not corroding the silver substrate, ensuring that no silver particles appear in the dicing lanes, and ensuring a good life of the silver stripping solution.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] The new formula of the present invention is based on a silver substrate wafer as a research object, and can effectively remove the surface photoresist without corrosion.

[0006] A silver stripping solution comprises the following components in parts by weight: 0.1-1 part of an imidazole reagent, 15-25 parts of an organic amine, 75-85 parts of an organic solvent, and 1-10 parts of a corrosion inhibitor.

[0007] Preferably, the imidazole reagent includes one or more of 2-mercaptobenzimidazole, benzotriazole, and 5-methylbenzotriazole.

[0008] Preferably, the organic amine comprises one or more of N,N-dimethylacetamide, ethanolamine and N-methylformamide.

[0009] Preferably, the organic solvent comprises one or more of a glycol organic solvent and a glycol ether organic solvent.

[0010] Preferably, the corrosion inhibitor comprises one or more of methylbenzotriazole sodium chloride and 1-methylpyrazole.

[0011] The preparation method of the silver stripping solution comprises the following specific steps:

[0012] (1) Add 2-mercaptobenzimidazole into a container all at once, weigh it, and record the weight;

[0013] (2) Continue to add N,N-dimethylacetamide, add all at once, weigh, and record the weight;

[0014] (3) Add N,N-dimethylacetamide, weigh, and record the weight;

[0015] (4) Continue to add corrosion inhibitor, weigh, and record the weight to obtain the silver stripping solution.

[0016] The silver stripping solution is used to clean silver substrate wafers, and the specific method is as follows:

[0017] (1) Add 20-50 L of silver stripping solution to a silver stripping solution tank and heat to 40-70° C.; then completely immerse 50-100 wafers in the silver stripping solution and shake and clean for 600-1000 seconds;

[0018] (2) Add 20-50 L of electronic grade isopropyl alcohol to an isopropyl alcohol tank at a temperature of 25-50° C. Then take out 50-100 wafers from the silver stripping tank, completely immerse them in the isopropyl alcohol tank, and shake and clean them for 480-800 seconds;

[0019] (3) Add 20-50L of ultrapure water to an ultrapure water tank at a temperature of 25-50°C; then take out 50-100 wafers from the isopropanol tank, completely immerse them in the ultrapure water tank, and shake and clean them for 600-1000 seconds;

[0020] (4) After the above cleaning process is completed, the wafer is centrifuged to remove residual moisture on the surface.

[0021] After the silver substrate wafers are cleaned through the above process, they are first visually inspected in a light box. The color of all wafer surfaces is uniform and there is no color difference. Then they are placed under a 3D microscope to observe the residual adhesive on the wafer surface and the residual silver particles in the dicing lanes. After being cleaned with the silver stripping solution, there is no residual adhesive on the surface of the wafers, and there are no particles in the dicing lanes.

[0022] The above process was repeated 15-20 times in the same batch of silver stripping solution, and a 3D microscope was used to check the residual glue on the wafer surface and the residual silver particles in the dicing lanes. No residual glue or residual particles in the dicing lanes were found. The silver stripping solution showed good product performance during the process.

[0023] Beneficial Effects

[0024] The present invention discloses a silver stripping solution and a preparation method and application thereof. Compared with the prior art, the present invention has the following beneficial effects:

[0025] The silver stripping solution product of the present invention has a silver substrate wafer as the object of action, and can effectively remove the surface photoresist without corrosion. The silver stripping solution of the present invention uses alcohol and ether as organic solvents, adds 15-25% of amine organic matter, adds imidazole reagents, etc. as photoresist stripping solution. During the experiment, the silver stripping solution can effectively remove the photoresist on the surface of the silver substrate wafer, and there is almost no residual glue; there are no silver particles in the scribe line, and there is no color difference after the wafer is baked, and the product yield is high; and more than 750 wafers can be cleaned during use, and the product has a long service life. And the product raw materials avoid the use of hazardous chemicals such as dimethyl sulfoxide, and implement the principle of green, non-toxic and sustainable development of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 :Flow chart of the silver stripping solution used to clean silver substrate wafers;

[0027] Figure 2 : Illustration of the silver substrate wafer in the light box in Example 1;

[0028] Figure 3 : Schematic diagram of residual adhesive on a silver substrate wafer under a 3D microscope in Example 1;

[0029] Figure 4 : Schematic diagram of the silver substrate wafer scribing path under a 3D microscope in Example 1;

[0030] Figure 5 : Illustration of the silver substrate wafer in the light box in Example 2;

[0031] Figure 6 : Schematic diagram of residual adhesive on a silver substrate wafer under a 3D microscope in Example 2;

[0032] Figure 7 : Schematic diagram of the silver substrate wafer scribing path under a 3D microscope in Example 2;

[0033] Figure 8 : Illustration of the silver substrate wafer in the light box in Example 3;

[0034] Fig. 9 : Schematic diagram of residual adhesive on a silver substrate wafer under a 3D microscope in Example 3;

[0035] Fig.10 : Schematic diagram of the silver substrate wafer scribing path under a 3D microscope in Example 3. DETAILED DESCRIPTION

[0036] Hereinafter, the present invention will be described in detail. Before describing, it should be understood that the terms used in this specification and the appended claims should not be interpreted as being limited to the general meaning and dictionary meaning, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the present invention on the basis of the principle that the inventor is allowed to appropriately define the terms for the best interpretation. Therefore, the descriptions presented here are only preferred examples for illustrative purposes and are not intended to limit the scope of the present invention, so that it should be understood that other equivalents or improvements can be obtained therefrom without departing from the spirit and scope of the present invention.

[0037] The following examples are only listed as examples of embodiments of the present invention and do not constitute any limitation to the present invention. It can be understood by those skilled in the art that modifications within the scope of the essence and concept of the present invention fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are all commercially available products.

[0038] Example 1

[0039] This embodiment discloses a silver stripping solution, the specific formula of which is as follows:

[0040] The composition comprises, by weight: 1 part of 2-mercaptobenzimidazole, 20 parts of N,N-dimethylacetamide, 75 parts of diol organic solvent, and 4 parts of corrosion inhibitor.

[0041] The preparation method of the silver stripping solution comprises the following specific steps:

[0042] (1) Add 2-mercaptobenzimidazole to a container, 1 part by weight, all at once; weigh and record the weight;

[0043] (2) Continue to add N,N-dimethylacetamide, 20 parts by weight, all at once; weigh and record the weight;

[0044] (3) Add 70 parts by weight of N,N-dimethylacetamide, weigh it, and record the weight;

[0045] (4) Continue to add 9 parts by weight of methylbenzotriazole sodium chloride, weigh it, and record the weight to obtain the silver stripping solution.

[0046] The silver stripping solution is used to clean silver substrate wafers, and the specific method is as follows:

[0047] (1) Add 20-50 L of silver stripping solution to a silver stripping solution tank and heat to 40-70° C.; then completely immerse 50-100 wafers in the silver stripping solution and shake and clean for 600-1000 seconds;

[0048] (2) Add 20-50 L of electronic grade isopropyl alcohol to an isopropyl alcohol tank at a temperature of 25-50° C. Then take out 50-100 wafers from the silver stripping tank, completely immerse them in the isopropyl alcohol tank, and shake and clean them for 480-800 seconds;

[0049] (3) Add 20-50L of ultrapure water to an ultrapure water tank at a temperature of 25-50°C; then take out 50-100 wafers from the isopropanol tank, completely immerse them in the ultrapure water tank, and shake and clean them for 600-1000 seconds;

[0050] After the above cleaning process is completed, the wafer is centrifuged to remove residual moisture on the surface.

[0051] The flow chart of the silver stripping solution for cleaning the silver substrate wafer is as follows Figure 1 shown.

[0052] After the silver substrate wafer is cleaned through the above process, first visually inspect it in a light box. Figure 2 As shown, the surface color of all the sheets is uniform and there is no color difference.

[0053] Then place it under a 3D microscope to observe the residual adhesive on the wafer surface and the residual silver particles in the dicing lanes. Figure 3-4 As shown in the figure, there is no residual glue on the surface of the wafer after cleaning with the silver stripping solution, and there are no particles in the dicing lanes.

[0054] Example 2

[0055] This embodiment discloses a silver stripping solution, the specific formula of which is as follows:

[0056] The composition comprises, by weight: 1 part of 2-mercaptobenzimidazole, 15 parts of N,N-dimethylacetamide, 80 parts of diol organic solvent, and 4 parts of corrosion inhibitor.

[0057] The preparation method of the silver stripping solution comprises the following specific steps:

[0058] (1) Add 2-mercaptobenzimidazole to a container, 1 part by weight, all at once; weigh and record the weight;

[0059] (2) Continue to add N,N-dimethylacetamide, 15 parts by weight, all at once; weigh and record the weight;

[0060] (3) Add 80 parts by weight of N,N-dimethylacetamide, weigh it, and record the weight;

[0061] (4) Continue to add 4 parts by weight of methylbenzotriazole sodium salt, weigh it, and record the weight;

[0062] The silver stripping solution is used to clean silver substrate wafers, and the specific method is as follows:

[0063] (1) Add 20-50 L of silver stripping solution to a silver stripping solution tank and heat to 40-70° C.; then completely immerse 50-100 wafers in the silver stripping solution and shake and clean for 600-1000 seconds;

[0064] (2) Add 20-50 L of electronic grade isopropyl alcohol to an isopropyl alcohol tank at a temperature of 25-50° C. Then take out 50-100 wafers from the silver stripping tank, completely immerse them in the isopropyl alcohol tank, and shake and clean them for 480-800 seconds;

[0065] (3) Add 20-50L of ultrapure water to an ultrapure water tank at a temperature of 25-50°C; then take out 50-100 wafers from the isopropanol tank, completely immerse them in the ultrapure water tank, and shake and clean them for 600-1000 seconds;

[0066] After the above cleaning process is completed, the wafer is centrifuged to remove residual moisture on the surface.

[0067] After the silver substrate wafer is cleaned through the above process, first visually inspect it in a light box. Figure 5 As shown, the surface color of all the sheets is uniform and there is no color difference.

[0068] Then place it under a 3D microscope to observe the residual adhesive on the wafer surface and the residual silver particles in the dicing lanes. Figure 6-7 As shown, there is no residual glue on the surface of the wafer after cleaning with the silver stripping solution, and there are no particles in the dicing lanes.

[0069] The above process was repeated 15-20 times in the same batch of silver stripping solution, and a 3D microscope was used to check the residual glue on the wafer surface and the residual silver particles in the dicing lanes. No residual glue or residual particles in the dicing lanes were found. The silver stripping solution showed good product performance during the process.

[0070] Example 3

[0071] This embodiment discloses a silver stripping solution, the specific formula of which is as follows:

[0072] The composition comprises, by weight: 0.5 parts of 2-mercaptobenzimidazole, 20 parts of N,N-dimethylacetamide, 75 parts of diol organic solvent, and 4.5 parts of corrosion inhibitor.

[0073] The preparation method of the silver stripping solution comprises the following specific steps:

[0074] (1) Add 0.5 parts by weight of 2-mercaptobenzimidazole into a container at one time; weigh and record the weight;

[0075] (2) Continue to add N,N-dimethylacetamide, 20 parts by weight, all at once; weigh and record the weight;

[0076] (3) Add 75 parts by weight of N,N-dimethylacetamide, weigh it, and record the weight;

[0077] (4) Continue to add 4.5 parts by weight of methylbenzotriazole sodium salt, weigh it, and record the weight;

[0078] The silver stripping solution is used to clean silver substrate wafers, and the specific method is as follows:

[0079] (1) Add 20-50 L of silver stripping solution to a silver stripping solution tank and heat to 40-70° C.; then completely immerse 50-100 wafers in the silver stripping solution and shake and clean for 600-1000 seconds;

[0080] (2) Add 20-50 L of electronic grade isopropyl alcohol to an isopropyl alcohol tank at a temperature of 25-50° C. Then take out 50-100 wafers from the silver stripping tank, completely immerse them in the isopropyl alcohol tank, and shake and clean them for 480-800 seconds;

[0081] (3) Add 20-50L of ultrapure water to an ultrapure water tank at a temperature of 25-50°C; then take out 50-100 wafers from the isopropanol tank, completely immerse them in the ultrapure water tank, and shake and clean them for 600-1000 seconds;

[0082] After the above cleaning process is completed, the wafer is centrifuged to remove residual moisture on the surface.

[0083] After the silver substrate wafer is cleaned through the above process, first visually inspect it in a light box. Figure 8 As shown, the surface color of all the sheets is uniform and there is no color difference.

[0084] Then place it under a 3D microscope to observe the residual adhesive on the wafer surface and the residual silver particles in the dicing lanes. Figure 9-10 As shown, there is no residual glue on the surface of the wafer after cleaning with the silver stripping solution, and there are no particles in the dicing lanes.

[0085] The above process was repeated 15-20 times in the same batch of silver stripping solution, and a 3D microscope was used to check the residual glue on the wafer surface and the residual silver particles in the dicing lanes. No residual glue or residual particles in the dicing lanes were found. The silver stripping solution showed good product performance during the process.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A silver stripping solution, characterized in that: The invention comprises the following components in parts by weight: 0.1-1 parts of imidazole reagent, 15-25 parts of organic amine, 75-85 parts of organic solvent and 1-10 parts of corrosion inhibitor.

2. The silver stripping solution according to claim 1, characterized in that The imidazole reagent includes one or more of 2-mercaptobenzimidazole, benzotriazole, and 5-methylbenzotriazole.

3. The silver stripping solution according to claim 1, characterized in that The organic amine comprises one or more of N,N-dimethylacetamide, ethanolamine and N-methylformamide.

4. The silver stripping solution according to claim 1, characterized in that The organic solvent comprises one or more of a glycol organic solvent and a glycol ether organic solvent.

5. The silver stripping solution according to claim 1, characterized in that The corrosion inhibitor comprises one or more of methylbenzotriazole sodium chloride and 1-methylpyrazole.

6. The method for preparing the silver stripping solution according to any one of claims 1 to 5, characterized in that: The specific steps are as follows: (1) Add 2-mercaptobenzimidazole into a container all at once, weigh it, and record the weight; (2) Continue to add N,N-dimethylacetamide, add all at once, weigh, and record the weight; (3) Add N,N-dimethylacetamide, weigh, and record the weight; (4) Continue to add the corrosion inhibitor, weigh, and record the weight to obtain the silver stripping solution.

7. The use of the silver stripping solution according to any one of claims 1 to 5, characterized in that: Used to clean silver substrate wafers.

8. The use of the silver stripping solution according to claim 7, characterized in that: The specific method is as follows: (1) Add 20-50 L of silver stripping solution to a silver stripping solution tank and heat it to 40-70° C.; then completely immerse 50-100 wafers in the silver stripping solution and shake and clean them for 600-1000 seconds; (2) Add 20-50 L of electronic grade isopropyl alcohol to an isopropyl alcohol tank at a temperature of 25-50° C. Then take out 50-100 wafers from the silver stripping tank, completely immerse them in the isopropyl alcohol tank, and shake and clean them for 480-800 seconds; (3) Add 20-50L of ultrapure water to an ultrapure water tank at a temperature of 25-50°C; then take out 50-100 wafers from the isopropanol tank, completely immerse them in the ultrapure water tank, and shake and clean them for 600-1000 seconds; (4) After the above cleaning process is completed, the wafer is centrifuged to remove residual moisture on the surface.

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