A method for cleaning silver bonded on the surface of a gold-plated chuck

Abstract

The present invention provides a cleaning method for the surface bonding silver of a gold-plated chuck, the cleaning method comprising: preparing a corrosive liquid, applying the corrosive liquid to the position where the surface of the gold-plated chuck is bonded with silver, and then wiping the surface of the gold-plated chuck for the first time; and applying an ethanol solution to the surface of the gold-plated chuck for the second time. Wherein, the corrosive liquid is mixed with nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in a volume ratio of (0.5-2):(0.5-2):(14-18):2, and the concentration of the nitric acid solution is 2-4wt%, the concentration of the acetic acid solution is 3-4wt%, and the concentration of the phosphoric acid solution is 72-73wt%. The cleaning method provided by the present invention adopts a corrosive liquid of a specific composition, can quickly clean the surface bonding silver of the gold-plated chuck, avoids the increase in equipment cost caused by replacing the chuck, and improves economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor manufacturing and relates to a method for cleaning silver bonded on the surface of a gold-plated chuck. Background Art

[0002] In the semiconductor manufacturing process, Wafer CP (wafer core test) machine is one of the key equipment. The gold-plated chuck (Chuck plate, also known as wafer table plate) plays the role of fixing the wafer during the test process. However, with the increase of use time, the surface of the chuck is very easy to adhere to silver, which will affect the accuracy of the test and the stability of the equipment.

[0003] Currently, the industry lacks an effective technical method to decompose the bonded silver on the surface of the cleaning chuck. Traditional cleaning methods often involve complex chemical treatment processes or require the replacement of the chuck, which not only increases costs but also prolongs the downtime of the equipment.

[0004] Therefore, how to develop a new cleaning technology that can effectively remove the adhesive silver and maintain the integrity of the chuck has become an urgent problem that technicians in this field need to solve. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for cleaning silver adhered to the surface of a gold-plated chuck, wherein the cleaning method can quickly clean the silver adhered to the surface of the gold-plated chuck, thereby avoiding the increase in equipment costs caused by replacing the chuck and significantly improving the economic benefits.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for cleaning silver bonded on the surface of a gold-plated chuck, the cleaning method comprising:

[0008] Prepare a corrosive liquid, apply the corrosive liquid to the portion of the gold-plated chuck surface where silver is bonded, and then perform a first wipe on the gold-plated chuck surface;

[0009] A second wipe was performed after applying an ethanol solution to the gold-plated chuck surface.

[0010] The etching solution is prepared by mixing nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in a volume ratio of (0.5-2):(0.5-2):(14-18):2, and the concentration of the nitric acid solution is 2-4wt%, the concentration of the acetic acid solution is 3-4wt%, and the concentration of the phosphoric acid solution is 72-73wt%.

[0011] In the present invention, the mixing volume ratio of the nitric acid solution, the acetic acid solution, the phosphoric acid solution and the deionized water is (0.5-2):(0.5-2):(14-18):2, for example, it can be 0.5:0.5:14:2, 1:1:15:2, 1.5:1.5:16:2 or 2:2:18:2, and is more preferably (1-1.5):1:16:2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0012] In the present invention, the concentration of the nitric acid solution is 2-4wt%, more preferably 2.96wt%; the concentration of the acetic acid solution is 3-4wt%, more preferably 3.37wt%; the concentration of the phosphoric acid solution is 72-73wt%, more preferably 72.82wt%.

[0013] The invention prepares the gold-silver separation etching solution by mixing a nitric acid solution, an acetic acid solution, a phosphoric acid solution and deionized water in a specific volume ratio. The obtained etching solution can dissolve silver but cannot dissolve gold, is particularly suitable for cleaning silver bonded on the surface of a gold-plated chuck, can quickly restore the chuck, meets the hardware technology requirements of a CP machine, avoids the increase in equipment cost caused by replacing the chuck, can quickly restore the equipment to run, prolongs the service life of the equipment, reduces the operating cost of the enterprise, and significantly improves the economic benefits.

[0014] In addition, the gold-silver separation etching liquid provided by the present invention is mixed with conventional acid liquid, and can be operated by employees who are familiar with chemical liquids without the need for professional technicians, thereby reducing the difficulty of operation. The obtained etching liquid is not only suitable for Wafer CP testing machines in the semiconductor industry, but can also be extended to other fields that require high-precision cleaning, and has good versatility and adaptability.

[0015] In the process of preparing and using the corrosive liquid, the operator needs to wear personal protective equipment such as a gas mask, acid and alkali resistant gloves and an apron to ensure the safety of the operator.

[0016] Preferably, the cleaning method further comprises:

[0017] The components of the disk surface are disassembled before cleaning the gold-plated chuck.

[0018] Preferably, the components include vacuum and compressed air pipeline connectors and a leveling and rotating mechanism.

[0019] Preferably, the gold-plated chuck is placed on a workbench with an acid- and alkali-proof pad after the components are disassembled.

[0020] Preferably, the cleaning method further comprises:

[0021] After removing the parts, the gold-plated chuck is connected to a hose, and the compressed air valve is opened so that the absolute pressure in the gold-plated chuck is 0.08-0.12MPa, for example, it can be 0.08MPa, 0.09MPa, 0.1MPa, 0.11MPa or 0.12MPa, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the hose is made of polyvinyl chloride.

[0023] Preferably, the outer diameter of the hose is 3-4 mm, for example, it can be 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm or 4 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the preparation method of the etching solution comprises: measuring nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water respectively, mixing them in one step and stirring them evenly.

[0025] Preferably, the stirring time is 15-20 min, for example, 15 min, 16 min, 17 min, 18 min, 19 min or 20 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, when the average thickness of the silver bonded to the surface of the gold-plated chuck is ≤0.5 μm, for example, it can be 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm or 0.5 μm, the volume ratio of nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water is 1:1:16:2.

[0027] Preferably, when the average thickness of the silver bonded to the surface of the gold-plated chuck is greater than 0.5 μm, for example, it can be 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm or 1.2 μm, the volume ratio of nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water is 1.5:1:16:2.

[0028] The invention flexibly adjusts the proportion of the nitric acid solution in the etching solution according to the average thickness of the silver bonded on the surface of the gold-plated chuck, thereby well taking into account both the cost of the reagent and the cleaning effect.

[0029] Preferably, the corrosive liquid is applied by coating and / or spraying, and more preferably by coating.

[0030] In the present invention, the corrosive liquid is applied with a soft acid- and alkali-resistant material. The soft acid- and alkali-resistant material can be a dust-free cloth head purification cotton swab, and the material of the cotton head can be ultrafine fiber or polyester fiber, the material of the swab rod can be polypropylene, and the material of the dust-free cloth can be polyester fiber.

[0031] Preferably, when the average thickness of the silver bonded to the surface of the gold-plated chuck is ≤0.5 μm, the waiting time between the first wiping and the application of the corrosive liquid is 1-2 min, for example, it can be 1 min, 1.1 min, 1.2 min, 1.3 min, 1.4 min, 1.5 min, 1.6 min, 1.7 min, 1.8 min, 1.9 min or 2 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, when the average thickness of the silver bonded to the surface of the gold-plated chuck is greater than 0.5 μm, the waiting time between the first wiping and the application of the corrosive liquid is 2-5 min, for example, it can be 2 min, 2.5 min, 3 min, 3.5 min, 4 min, 4.5 min or 5 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] The present invention flexibly adjusts the waiting time (ie, the corrosion time) according to the average thickness of the bonding silver on the surface of the gold-plated chuck, thereby achieving full removal of the bonding silver and ensuring a cleaning effect.

[0034] Preferably, the first wiping and the second wiping are performed using a dust-free cloth and / or an eraser respectively.

[0035] Preferably, the ethanol solution is applied by applying and / or spraying, more preferably by spraying.

[0036] Preferably, the concentration of the ethanol solution is ≥ 95wt%, for example, it can be 95wt%, 95.5wt%, 96wt%, 96.5wt%, 97wt%, 97.5wt%, 98wt%, 98.5wt% or 99wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] The present invention adopts ethanol solution as the final cleaning agent. Since ethanol has little impact on the environment and has no corrosive effect on equipment, both environmental protection requirements and cleaning effects are taken into account.

[0038] Preferably, the second wiping method includes: wiping in a spiral trajectory from the center point of the gold-plated chuck outwards.

[0039] Preferably, the second wiping is performed 2-5 times, for example, 2 times, 3 times, 4 times or 5 times.

[0040] As a preferred technical solution of the present invention, the cleaning method comprises the following steps:

[0041] (1) Remove the vacuum and compressed air pipe joints and the leveling rotating mechanism on the surface of the gold-plated chuck, then place the gold-plated chuck on a workbench with an acid- and alkali-proof pad, then connect a polyvinyl chloride hose with an outer diameter of 3-4 mm to the gold-plated chuck, and open the compressed air valve so that the absolute pressure in the gold-plated chuck is 0.08-0.12 MPa;

[0042] (2) respectively measuring nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water, mixing them in one step and stirring for 15-20 minutes to obtain a etching solution; applying and / or spraying the etching solution to the silver bonding portion of the gold-plated chuck surface, and then wiping the gold-plated chuck surface with a dust-free cloth and / or an eraser;

[0043] (3) Apply and / or spray an ethanol solution with a concentration of ≥95 wt % onto the surface of the gold-plated chuck, and then use a dust-free cloth and / or eraser to wipe the surface of the gold-plated chuck 2-5 times in a spiral trajectory from the center point of the gold-plated chuck outward.

[0044] Wherein, the etching solution in step (2) is mixed with nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in a volume ratio of (0.5-2):(0.5-2):(14-18):2, and the concentration of the nitric acid solution is 2-4wt%, the concentration of the acetic acid solution is 3-4wt%, and the concentration of the phosphoric acid solution is 72-73wt%; when the average thickness of the silver bonded to the surface of the gold-plated chuck is ≤0.5μm, the volume ratio of the nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in step (2) is 1:1:16:2, and the waiting time before the first wiping is 1-2min; when the average thickness of the silver bonded to the surface of the gold-plated chuck is >0.5μm, the volume ratio of the nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in step (2) is 1.5:1:16:2, and the waiting time before the first wiping is 2-5min.

[0045] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The present invention prepares a gold-silver separation etching solution by mixing a nitric acid solution, an acetic acid solution, a phosphoric acid solution and deionized water in a specific volume ratio. The obtained etching solution can dissolve silver but cannot dissolve gold. The etching solution is particularly suitable for cleaning silver bonded to the surface of a gold-plated chuck. The chuck can be quickly restored, meeting the hardware technology requirements of the CP machine, avoiding the increase in equipment cost caused by replacing the chuck, and can quickly restore the equipment to run, thereby extending the service life of the equipment, reducing the operating cost of the enterprise, and significantly improving the economic benefits.

[0048] (2) The gold-silver separation etching solution provided by the present invention is prepared by mixing conventional acid solutions, and can be operated by employees who are familiar with chemical solutions without the need for professional technicians, thereby reducing the difficulty of operation. The obtained etching solution is not only suitable for Wafer CP testers in the semiconductor industry, but can also be extended to other fields requiring high-precision cleaning, and has good versatility and adaptability. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0050] Example 1

[0051] This embodiment provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 0.1 μm. The cleaning method comprises the following steps:

[0052] (1) Remove the vacuum and compressed air pipe joints and the leveling rotating mechanism on the surface of the gold-plated chuck, and stick the plastic film on the table to prevent damage to the surface of the chuck; then place the gold-plated chuck on a workbench with an acid-proof and alkali-proof pad, and then connect a polyvinyl chloride hose with an outer diameter of 3.5 mm to the gold-plated chuck, and open the compressed air valve so that the absolute pressure in the gold-plated chuck is 0.1 MPa;

[0053] (2) 2.96 wt% nitric acid solution, 3.37 wt% acetic acid solution, 72.82 wt% phosphoric acid solution and deionized water were measured in a volume ratio of 1:1:16:2, mixed in one step and stirred for 18 minutes to obtain a corrosion solution; a clean cotton swab with a dust-free cloth head (the cotton head and the dust-free cloth are made of polyester fiber, and the swab rod is made of polypropylene) was dipped in the corrosion solution and applied to the silver bonding part of the gold-plated chuck surface, and after waiting for 1 minute, the surface of the gold-plated chuck was wiped for the first time with a dust-free cloth and an eraser;

[0054] (3) Spray an ethanol solution with a concentration of 96 wt % onto the surface of the gold-plated chuck, and then use a dust-free cloth to wipe the surface of the gold-plated chuck twice in a spiral trajectory from the center point of the gold-plated chuck to the outside.

[0055] In the process of preparing and using the corrosive liquid in this embodiment, the operator needs to wear personal protective equipment such as a gas mask, acid and alkali resistant gloves and an apron to ensure the safety of the operator.

[0056] Example 2

[0057] This embodiment provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 0.3 μm. The cleaning method comprises the following steps:

[0058] (1) Remove the vacuum and compressed air pipe joints and the leveling rotating mechanism on the surface of the gold-plated chuck, and stick the plastic film on the table to prevent damage to the surface of the chuck; then place the gold-plated chuck on a workbench with an acid-proof and alkali-proof pad, and then connect a polyvinyl chloride hose with an outer diameter of 3 mm to the gold-plated chuck, and open the compressed air valve so that the absolute pressure in the gold-plated chuck is 0.08 MPa;

[0059] (2) 2.96 wt % nitric acid solution, 3.37 wt % acetic acid solution, 72.82 wt % phosphoric acid solution and deionized water were measured in a volume ratio of 1:1:16:2, mixed in one step and stirred for 15 minutes to obtain a corrosion solution; a cotton swab with a dust-free cloth head (the cotton head and the dust-free cloth are made of polyester fiber, and the swab rod is made of polypropylene) was dipped in the corrosion solution and applied to the silver bonding part of the gold-plated chuck surface; after waiting for 1.5 minutes, the surface of the gold-plated chuck was wiped for the first time with a dust-free cloth and an eraser;

[0060] (3) Spray an ethanol solution with a concentration of 98 wt % onto the surface of the gold-plated chuck, and then use a dust-free cloth to wipe the surface of the gold-plated chuck three times in a spiral trajectory from the center point of the gold-plated chuck to the outside.

[0061] In the process of preparing and using the corrosive liquid in this embodiment, the operator needs to wear personal protective equipment such as a gas mask, acid and alkali resistant gloves and an apron to ensure the safety of the operator.

[0062] Example 3

[0063] This embodiment provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 0.5 μm. The cleaning method comprises the following steps:

[0064] (1) Remove the vacuum and compressed air pipe joints and the leveling rotating mechanism on the surface of the gold-plated chuck, and stick the plastic film on the table to prevent damage to the surface of the chuck; then place the gold-plated chuck on a workbench with an acid-proof and alkali-proof pad, and then connect a polyvinyl chloride hose with an outer diameter of 4 mm to the gold-plated chuck, and open the compressed air valve so that the absolute pressure in the gold-plated chuck is 0.12 MPa;

[0065] (2) 2.96 wt % nitric acid solution, 3.37 wt % acetic acid solution, 72.82 wt % phosphoric acid solution and deionized water were measured in a volume ratio of 1:1:16:2, mixed in one step and stirred for 20 minutes to obtain a corrosion solution; a clean cotton swab with a dust-free cloth head (the cotton head and the dust-free cloth are made of polyester fiber, and the swab rod is made of polypropylene) was dipped in the corrosion solution and then applied to the silver bonding part of the gold-plated chuck surface, and after waiting for 2 minutes, the surface of the gold-plated chuck was wiped for the first time with a dust-free cloth and an eraser;

[0066] (3) Spray an ethanol solution with a concentration of 96 wt % onto the surface of the gold-plated chuck, and then use a dust-free cloth to wipe the surface of the gold-plated chuck five times in a spiral trajectory from the center point of the gold-plated chuck to the outside.

[0067] In the process of preparing and using the corrosive liquid in this embodiment, the operator needs to wear personal protective equipment such as a gas mask, acid and alkali resistant gloves and an apron to ensure the safety of the operator.

[0068] Example 4

[0069] This embodiment provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 0.6 μm. The cleaning method comprises the following steps:

[0070] (1) Remove the vacuum and compressed air pipe joints and the leveling rotating mechanism on the surface of the gold-plated chuck, and stick the plastic film on the table to prevent damage to the surface of the chuck; then place the gold-plated chuck on a workbench with an acid-proof and alkali-proof pad, and then connect a polyvinyl chloride hose with an outer diameter of 3.5 mm to the gold-plated chuck, and open the compressed air valve so that the absolute pressure in the gold-plated chuck is 0.1 MPa;

[0071] (2) 2.96 wt % nitric acid solution, 3.37 wt % acetic acid solution, 72.82 wt % phosphoric acid solution and deionized water were measured in a volume ratio of 1.5:1:16:2, mixed in one step and stirred for 18 minutes to obtain a corrosion solution; a cotton swab with a dust-free cloth head (the cotton head and the dust-free cloth are made of polyester fiber, and the swab rod is made of polypropylene) was dipped in the corrosion solution and applied to the silver bonding part of the gold-plated chuck surface; after waiting for 2 minutes, the surface of the gold-plated chuck was wiped for the first time with a dust-free cloth and an eraser;

[0072] (3) Spray an ethanol solution with a concentration of 98 wt % onto the surface of the gold-plated chuck, and then use a dust-free cloth to wipe the surface twice in a spiral trajectory from the center point of the gold-plated chuck outward.

[0073] In the process of preparing and using the corrosive liquid in this embodiment, the operator needs to wear personal protective equipment such as a gas mask, acid and alkali resistant gloves and an apron to ensure the safety of the operator.

[0074] Example 5

[0075] This embodiment provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 0.8 μm. The cleaning method comprises the following steps:

[0076] (1) Remove the vacuum and compressed air pipe joints and the leveling rotating mechanism on the surface of the gold-plated chuck, and stick the plastic film on the table to prevent damage to the surface of the chuck; then place the gold-plated chuck on a workbench with an acid-proof and alkali-proof pad, and then connect a polyvinyl chloride hose with an outer diameter of 3 mm to the gold-plated chuck, and open the compressed air valve so that the absolute pressure in the gold-plated chuck is 0.08 MPa;

[0077] (2) 2.96 wt % nitric acid solution, 3.37 wt % acetic acid solution, 72.82 wt % phosphoric acid solution and deionized water were measured in a volume ratio of 1.5:1:16:2, mixed in one step and stirred for 15 minutes to obtain a corrosion solution; a clean cotton swab with a dust-free cloth head (the cotton head and the dust-free cloth are made of polyester fiber, and the swab rod is made of polypropylene) was dipped in the corrosion solution and applied to the silver bonding part of the gold-plated chuck surface; after waiting for 3 minutes, the surface of the gold-plated chuck was wiped for the first time with a dust-free cloth and an eraser;

[0078] (3) Spray an ethanol solution with a concentration of 96 wt % onto the surface of the gold-plated chuck, and then use a dust-free cloth to wipe the surface of the gold-plated chuck three times in a spiral trajectory from the center point of the gold-plated chuck to the outside.

[0079] In the process of preparing and using the corrosive liquid in this embodiment, the operator needs to wear personal protective equipment such as a gas mask, acid and alkali resistant gloves and an apron to ensure the safety of the operator.

[0080] Example 6

[0081] This embodiment provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 1.2 μm. The cleaning method comprises the following steps:

[0082] (1) Remove the vacuum and compressed air pipe joints and the leveling rotating mechanism on the surface of the gold-plated chuck, and stick the plastic film on the table to prevent damage to the surface of the chuck; then place the gold-plated chuck on a workbench with an acid-proof and alkali-proof pad, and then connect a polyvinyl chloride hose with an outer diameter of 4 mm to the gold-plated chuck, and open the compressed air valve so that the absolute pressure in the gold-plated chuck is 0.12 MPa;

[0083] (2) 2.96 wt % nitric acid solution, 3.37 wt % acetic acid solution, 72.82 wt % phosphoric acid solution and deionized water were measured in a volume ratio of 1.5:1:16:2, mixed in one step and stirred for 20 min to obtain a corrosion solution; a clean cotton swab with a dust-free cloth head (the cotton head and the dust-free cloth are made of polyester fiber, and the swab rod is made of polypropylene) was dipped in the corrosion solution and then applied to the silver bonding part of the gold-plated chuck surface; after waiting for 5 min, the surface of the gold-plated chuck was wiped for the first time with a dust-free cloth and an eraser;

[0084] (3) Spray an ethanol solution with a concentration of 98 wt % onto the surface of the gold-plated chuck, and then use a dust-free cloth to wipe the surface of the gold-plated chuck five times in a spiral trajectory from the center point of the gold-plated chuck outward.

[0085] In the process of preparing and using the corrosive liquid in this embodiment, the operator needs to wear personal protective equipment such as a gas mask, acid and alkali resistant gloves and an apron to ensure the safety of the operator.

[0086] Example 7

[0087] The present embodiment provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 1.2 μm. The cleaning method is the same as that of Example 6 except that the volume ratio of the nitric acid solution, the acetic acid solution, the phosphoric acid solution and the deionized water is changed to 1:1:16:2. Therefore, they are not described in detail here.

[0088] Example 8

[0089] This embodiment provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 1.2 μm. Except for changing the waiting time before the first wiping to 1 minute, the remaining steps and conditions of the cleaning method are the same as those of Example 6, so they are not repeated here.

[0090] Comparative Example 1

[0091] This comparative example provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 1.2 μm. The cleaning method is the same as Example 6 except that the etching solution is changed to a 2.96 wt % nitric acid solution, and the remaining steps and conditions are the same as those in Example 6, so they are not described here.

[0092] Comparative Example 2

[0093] This comparative example provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 1.2 μm. The cleaning method is the same as Example 6 except that the etching solution is changed to a mixed solution of 2.96 wt % nitric acid solution and 3.37 wt % acetic acid solution in a mixing volume ratio of 1:1. Therefore, they are not described in detail here.

[0094] Comparative Example 3

[0095] This comparative example provides a method for cleaning silver bonded to the surface of a gold-plated chuck. After testing, the average thickness of the bonded silver is 1.2 μm. The cleaning method is the same as Example 6 except that the etching solution is changed to a mixed solution of 2.96 wt % nitric acid solution and 72.82 wt % phosphoric acid solution, and the mixed volume ratio is 1:16. Therefore, it will not be repeated here.

[0096] After testing, the cleaning effects of the silver bonded on the surface of the gold-plated chucks obtained in Examples 1-8 and Comparative Examples 1-3 are shown in Table 1 below.

[0097] Table 1

[0098]

[0099]

[0100] It can be seen from Table 1 that there is no adhesive silver on the surface of the gold-plated chuck obtained in Examples 1-6 after cleaning, and the removal rate is as high as 100%; since Example 7 adjusts the volume ratio of each component in the etching solution, its cleaning effect is significantly reduced; similarly, since Example 8 adjusts the waiting time before the first wiping, its cleaning effect is also significantly reduced; since Comparative Examples 1-3 respectively adjust the acid components in the etching solution, their cleaning effects are reduced to varying degrees.

[0101] It can be seen that the present invention prepares the gold-silver separation etching solution by mixing nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in a specific volume ratio. The obtained etching solution can dissolve silver but cannot dissolve gold. It is particularly suitable for cleaning silver bonded on the surface of a gold-plated chuck, and can quickly restore the chuck, meeting the hardware technology requirements of the CP machine, avoiding the increase in equipment cost caused by replacing the chuck, and can quickly restore the equipment operation, thereby extending the service life of the equipment, reducing the operating cost of the enterprise, and significantly improving the economic benefits.

[0102] In addition, the gold-silver separation etching liquid provided by the present invention is mixed with conventional acid liquid, and can be operated by employees who are familiar with chemical liquids without the need for professional technicians, thereby reducing the difficulty of operation. The obtained etching liquid is not only suitable for Wafer CP testing machines in the semiconductor industry, but can also be extended to other fields that require high-precision cleaning, and has good versatility and adaptability.

[0103] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for cleaning silver bonded to the surface of a gold-plated chuck, characterized in that: The cleaning method comprises: Prepare a corrosive liquid, and apply the corrosive liquid to the portion of the surface of the gold-plated chuck where the silver is bonded, and then perform a first wiping on the surface of the gold-plated chuck; Applying an ethanol solution to the surface of the gold-plated chuck and then performing a second wiping; The etching solution is prepared by mixing nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in a volume ratio of (0.5-2):(0.5-2):(14-18):2, and the concentration of the nitric acid solution is 2-4wt%, the concentration of the acetic acid solution is 3-4wt%, and the concentration of the phosphoric acid solution is 72-73wt%.

2. The cleaning method according to claim 1, characterized in that: The cleaning method further comprises: Disassembling components of the disk surface before cleaning the gold-plated chuck; Among them, the parts include vacuum and compressed air pipeline joints and leveling and rotating mechanisms; And / or, the gold-plated chuck is placed on a workbench with an acid-proof and alkali-proof pad after the parts are disassembled.

3. The cleaning method according to claim 2, characterized in that: The cleaning method further comprises: After the components are disassembled, the gold-plated chuck is connected to a hose, and the compressed air valve is opened so that the absolute pressure in the gold-plated chuck is 0.08-0.12 MPa; Wherein, the material of the hose is polyvinyl chloride; And / or, the outer diameter of the hose is 3-4 mm.

4. The cleaning method according to claim 1, characterized in that: The preparation method of the etching solution comprises: measuring nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water respectively, mixing them in one step and stirring them evenly, and the stirring time is 15-20 minutes.

5. The cleaning method according to claim 1, characterized in that: When the average thickness of the silver bonded to the surface of the gold-plated chuck is ≤0.5 μm, the volume ratio of the nitric acid solution, the acetic acid solution, the phosphoric acid solution and the deionized water is 1:1:16:2; Alternatively, when the average thickness of silver bonded to the surface of the gold-plated chuck is greater than 0.5 μm, the volume ratio of the nitric acid solution, the acetic acid solution, the phosphoric acid solution and the deionized water is 1.5:1:16:

2.

6. The cleaning method according to claim 1, characterized in that: The corrosive liquid is applied by applying and / or spraying; and / or, when the average thickness of the silver bonded to the surface of the gold-plated chuck is ≤0.5 μm, the waiting time between the first wiping and the application of the etching solution is 1-2 min; Alternatively, when the average thickness of the silver bonded to the surface of the gold-plated chuck is greater than 0.5 μm, the waiting time between the first wiping and the application of the etching solution is 2-5 minutes.

7. The cleaning method according to claim 1, characterized in that: The first wiping and the second wiping are performed respectively using a dust-free cloth and / or an eraser.

8. The cleaning method according to claim 1, characterized in that: The ethanol solution is applied by applying and / or spraying; And / or, the concentration of the ethanol solution is ≥95wt%.

9. The cleaning method according to claim 1, characterized in that: The second wiping method includes: wiping from the center point of the gold-plated chuck outward in a spiral trajectory; And / or, the second wiping is performed 2-5 times.

10. The cleaning method according to any one of claims 1 to 9, characterized in that: The cleaning method comprises the following steps: (1) Remove the vacuum and compressed air pipe joints and the leveling rotating mechanism on the surface of the gold-plated chuck, then place the gold-plated chuck on a workbench with an acid- and alkali-proof pad, then connect a polyvinyl chloride hose with an outer diameter of 3-4 mm to the gold-plated chuck, and open the compressed air valve so that the absolute pressure in the gold-plated chuck is 0.08-0.12 MPa; (2) respectively measuring nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water, mixing them in one step and stirring for 15-20 minutes to obtain a etching solution; applying and / or spraying the etching solution to the silver bonding portion of the gold-plated chuck surface, and then wiping the gold-plated chuck surface with a dust-free cloth and / or an eraser; (3) Apply and / or spray an ethanol solution with a concentration of ≥95 wt % onto the surface of the gold-plated chuck, and then use a dust-free cloth and / or eraser to wipe the surface of the gold-plated chuck 2-5 times in a spiral trajectory from the center point of the gold-plated chuck outward; Wherein, the etching solution in step (2) is mixed with nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in a volume ratio of (0.5-2):(0.5-2):(14-18):2, and the concentration of the nitric acid solution is 2-4wt%, the concentration of the acetic acid solution is 3-4wt%, and the concentration of the phosphoric acid solution is 72-73wt%; when the average thickness of the silver bonded to the surface of the gold-plated chuck is ≤0.5μm, the volume ratio of the nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in step (2) is 1:1:16:2, and the waiting time before the first wiping is 1-2min; when the average thickness of the silver bonded to the surface of the gold-plated chuck is >0.5μm, the volume ratio of the nitric acid solution, acetic acid solution, phosphoric acid solution and deionized water in step (2) is 1.5:1:16:2, and the waiting time before the first wiping is 2-5min.

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