Method for cleaning tantalum nitride pollutants on surface of aluminum alloy part

Abstract

The invention relates to the technical field of semiconductor equipment part cleaning, and particularly discloses a method for cleaning tantalum nitride pollutants on the surface of an aluminum alloy part, which comprises the following steps: part protection and medicine immersion, water washing, part protection and sand blasting, meltallizing, ultrasonic cleaning and post-treatment. Wherein liquid medicine in the medicine soaking step is formed by compounding 70% nitric acid, N-methyl pyrrolidone and water according to the volume ratio of 1: (0.15-0.3): (0.8-1.2); in the part protection and sand blasting step, firstly, a white corundum sand material WA60 # is adopted to carry out stripping sand blasting on the part, and then a white corundum sand material WA24 # is adopted to carry out fine sand blasting; in the part protection and meltallizing step, aluminum is uniformly meltallized on the meltallizing surface of the aluminum alloy part. According to the cleaning method provided by the invention, the tantalum nitride on the surface of the aluminum alloy component can be efficiently removed while the damage to the component is reduced, and the repeated utilization of the aluminum alloy component is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor equipment parts cleaning, in particular to a cleaning method for tantalum nitride contaminants on the surface of an aluminum alloy part. BACKGROUND

[0002] In the field of semiconductor manufacturing, the precision aluminum parts of the equipment are often deposited or attached with various types of contaminants that are difficult to remove in a complex process environment. As a common barrier or hard mask material, tantalum nitride (TaN) is one of the typical stubborn contaminants. If these contaminated parts cannot be effectively cleaned and their surface state is not restored, it will directly lead to a sharp increase in production cost and may affect the production yield of semiconductor devices.

[0003] Currently, the industry mainly uses super-high pressure water washing to remove tantalum nitride contaminants on the surface of aluminum alloy parts. However, the above method has the following problems in actual application: first, the energy of the super-high pressure water flow is too concentrated and difficult to control accurately, which can easily cause irreversible damage such as punching to the aluminum alloy part body which is structurally precise and relatively soft in material, resulting in permanent scrap of the part. In addition, the trace impurities possibly wrapped in the water flow or the debris generated in the stripping process can produce a large number of scratches on the exposed surface of the part under high pressure, seriously damaging its surface finish and dimensional accuracy, and thus failing to meet the strict standards of customers when the part is reused.

[0004] Therefore, it is of great significance to develop a cleaning method for aluminum alloy parts that can balance cleaning thoroughness and part safety for the maintenance of precision spare parts of semiconductor industry equipment. SUMMARY

[0005] In order to overcome the problem that the existing cleaning method for removing tantalum nitride contaminants on the surface of aluminum alloy parts cannot balance cleaning effect and part protection, the present application provides a cleaning method for tantalum nitride contaminants on the surface of an aluminum alloy part.

[0006] The present application provides a cleaning method for tantalum nitride contaminants on the surface of an aluminum alloy part, which adopts the following technical solution: A cleaning method for tantalum nitride contaminants on the surface of an aluminum alloy part, comprising the following steps: part protection and chemical immersion, water washing, part protection and sand blasting, part protection and melting, ultrasonic cleaning, post-treatment; Part protection and chemical immersion: the sealing surface of the part is pre-protected with acid and alkali resistant adhesive tape, and then immersed in a chemical solution at 40-45℃ for 0.5-2h. When the contaminant film on the surface of the aluminum alloy part is about to be removed, the aluminum alloy part is taken out. The chemical solution is compounded by 70% nitric acid, N-methyl pyrrolidone and water, with a volume ratio of 1: (0.15-0.3): (0.8-1.2); Component protection and sandblasting: The sealing surfaces of the components are protected with black tape, then the components are peeled and sandblasted using WA60# white corundum abrasive at a pressure of 3-5 kg / cm². 2 Then, fine sandblasting is performed using white fused alumina abrasive WA24# at a pressure of 3-4 kg / cm². 2 ; Component protection and spraying: Protect the sealing surface of the component with yellow spraying tape, and uniformly spray aluminum onto the spraying surface of the aluminum alloy component to achieve a surface roughness Rz of 180-220μm.

[0007] This application provides a method for cleaning tantalum nitride contaminants on the surface of aluminum alloy components. The method first involves immersing the aluminum alloy components in a chemically prepared solution at 40-45°C to weaken the adhesion between the contaminants and the substrate, dissolving the contaminants and their organic impurities, thus facilitating the detachment of the tantalum nitride film from the component surface. Next, small-particle white corundum abrasive is used for peeling and sandblasting, efficiently and thoroughly removing the tantalum nitride contaminants from the surface while minimizing damage to the aluminum component. This also results in a uniform and initially roughened surface. Further fine sandblasting with larger-particle white corundum abrasive is then performed, achieving a surface roughness suitable for aluminum deposition during subsequent lamination processes. Finally, a layer of aluminum is uniformly laminationed onto the lamination surface of the aluminum alloy component, achieving a surface roughness Rz of 180-220 μm, thus meeting the requirements for reusability of the aluminum alloy component.

[0008] This application provides a method for cleaning tantalum nitride contaminants from the surface of aluminum alloy components. This method is applicable to cleaning contaminants (tantalum nitride) adhering to the surface of aluminum alloy components inside the equipment cavity during the PVD (Physical Vapor Deposition) process in semiconductor chip fabrication. In the production process, by promptly cleaning the contaminants on the surface of the aluminum alloy components, the performance (surface roughness of the welded surface) and appearance of the cleaned components can be restored to their original levels. This ensures that the aluminum alloy components can be reused in the equipment cavity for tantalum nitride deposition, achieving reuse of the aluminum alloy components, greatly improving production efficiency, and reducing spare parts inventory and holding costs.

[0009] Optionally, the surface contaminant comprises tantalum nitride.

[0010] Optionally, in the water washing step, the component is first soaked in pure water for 25-40 minutes, then rinsed with a high-pressure water gun at a pressure of 220-250 bar for 2-3 minutes, and then dried at 75-85°C.

[0011] Optionally, after the component protection and sandblasting are completed, the component also needs to be rinsed with a high-pressure water gun. The water gun pressure is 180-200 bar, the gun head is 20-40 cm away from the component, and the rinsing time is 2-3 minutes. After rinsing, it is dried at 95-105℃.

[0012] Optionally, after the welding process is completed, the welding protective tape is removed, and the component is rinsed with a high-pressure water gun at a pressure of 220-250 bar, with the gun head 20-40 cm away from the component, for a rinsing time of 2-3 minutes; after rinsing, the component is dried in an oven at 95-105℃.

[0013] Optionally, during the ultrasonic cleaning process, the ultrasonic intensity is 4-10 W / in. 2 The time is 30-60 minutes.

[0014] In this application, ultrasonic cleaning may include multi-stage processing.

[0015] Optionally, the post-processing includes drying at a temperature of 140-160°C for 2-3 hours.

[0016] In summary, this application has the following beneficial effects: 1. This application uses a mixture of 70% nitric acid, N-methylpyrrolidone and water in a volume ratio of 1:(0.15-0.3):(0.8-1.2) as a solution to perform preliminary chemical immersion on aluminum alloy parts. This can destroy the tantalum nitride deposited layer structure on the surface of the aluminum alloy while avoiding corrosion, effectively dissolving the tantalum nitride deposited layer and the organic impurities therein, and improving cleaning efficiency.

[0017] 2. In the sandblasting step of this application, by using white fused alumina abrasive WA60# to peel and sandblast the component, the residual film on the surface of the component can be effectively removed, and the surface of the component can be sprayed evenly and initially roughened; then, white fused alumina abrasive WA24# is used for fine sandblasting, which can increase the roughness of the surface of the component and facilitate the deposition of aluminum in the subsequent melting process.

[0018] 3. In the spraying step of this application, aluminum is uniformly sprayed onto the spraying surface of the aluminum alloy component, and the surface roughness Rz of the spraying surface reaches 180-220μm, thereby ensuring that the aluminum alloy component can be reused and greatly reducing spare parts inventory and holding costs. Detailed Implementation

[0019] This application provides a method for cleaning tantalum nitride contaminants on the surface of aluminum alloy parts, including the following steps: (1) Component protection and immersion in chemicals: First, fill the liquid washing tank with heating rods with water and heat the water to 40-45℃. Then, prepare 70% electronic grade nitric acid, N-methylpyrrolidone and water in a sub-tank at a volume ratio of 1:(0.15-0.3):(0.8-1.2). The sub-tank heats the chemical solution to 40-45℃ through heat transfer. Protect the sealing surface of the component with acid and alkali resistant tape. Then carefully put the component into the sub-tank and soak for 0.5-2 hours. During this period, observe the film removal status at any time. When the film is about to be removed, take the component out of the sub-tank.

[0020] (2) Water washing: Rinse the parts with water to remove the liquid, then soak them in a pure water tank for 25-40 minutes with the pure water overflowing; after water washing, continue to rinse the parts with a high-pressure water gun with a pressure of 220-250 bar and the nozzle 20-40 cm away from the parts for 2-3 minutes; after rinsing, dry them in an oven at 75-85℃.

[0021] (3) Component protection and sandblasting: The sealing surface of the component is protected with black tape, and then the component is peeled and sandblasted with white corundum abrasive WA60# at a pressure of 3-5 kg / cm. 2 The purpose is to remove residual film and to spray the surface of the component to a uniform and preliminary roughening level in order to increase the roughness later; then, fine sandblasting is performed using white fused alumina abrasive WA24# at a pressure of 3-4 kg / cm. 2 The purpose is to increase the surface roughness of the parts. After that, use an air gun to blow away the particles on the surface of the parts and remove the protective tape. Wipe off the tape marks with IPA (isopropyl alcohol). Then, use a high-pressure water gun to rinse the parts. The water gun pressure is 180-200 bar, the gun head is 20-40 cm away from the parts, and the rinsing time is 2-3 minutes. After rinsing, dry in an oven at 95-105℃.

[0022] (4) Component protection and spraying: Within 4 hours after drying, protect the sealing surface of the component with yellow spraying tape. Set the spraying machine program to 65Psi air pressure and 200A current, and spray aluminum evenly onto the spraying surface of the aluminum alloy component so that the surface roughness Rz of the spraying surface is 180-220μm. After completion, remove the spraying protective tape and check whether there are spraying burrs on the edge. Use a high-pressure water gun to rinse the component. The water gun pressure is 220-250bar, the gun head is 20-40cm away from the component, and the rinsing time is 2-3min. After rinsing, dry in an oven at 95-105℃.

[0023] (5) Ultrasonic cleaning: Place the parts in an ultrasonic cleaning tank and use deionized water for ultrasonic cleaning. The deionized water should be in an overflow state, and the ultrasonic intensity should be 4-10 W / in. 2The cleaning time is 30-40 minutes; note that parts should not be stacked to prevent friction marks from ultrasonic vibration; after cleaning, dry in an oven at 95-105℃; then place the parts in the ultrasonic cleaning tank of the clean room and perform ultrasonic cleaning with deionized water. The deionized water should be in an overflow state, and the ultrasonic intensity should be 4-10W / in. 2 The cleaning time is 15-20 minutes. After cleaning, high-purity nitrogen (99.999%) is used to purge the surface to remove water droplets from the component surface. The purging pressure is 30±5Psi.

[0024] (6) Post-processing: Transfer the purged parts to a clean drying oven, gradually raise the temperature to 140-160℃ according to the program, dry for 2-3 hours, and wait for the parts to cool naturally to below 40℃. Take them out, and after passing the quality inspection, vacuum seal the parts with two layers of PE bags. Before packaging, purge the whole part with nitrogen gas at a pressure of 30±5Psi.

[0025] In this application, aluminum alloy components refer to aluminum alloy components used for surface deposition of tantalum nitride, including but not limited to lower shields or upper shields; the acid and alkali resistant tape is K2550 gold finger PI tape, the black tape is purchased from Nitto Denko Corporation, Taiwan, and the yellow melt spraying tape is PT28287-W, purchased from Shanghai Jingxin Metal Products Co., Ltd.; the high-pressure water gun is HD10 / 25-4S; the raw materials, reagents, solvents, etc. used in this application can all be obtained commercially.

[0026] The present application will be further described in detail below with reference to embodiments and performance testing.

[0027] Example 1 Example 1 provides a method for cleaning tantalum nitride contaminants on the surface of aluminum alloy parts, including the following steps: (1) Component protection and drug immersion: First, fill the liquid washing tank with heating rod with water and heat the water to 45°C. Then, prepare 70% electronic grade nitric acid, N-methylpyrrolidone and water in a volume ratio of 1:0.2:1 in the sub-tank. The sub-tank heats the drug solution to 45°C through heat transfer. Protect the sealing surface of the lower shield component with acid and alkali resistant tape. Then carefully put the component into the sub-tank for immersion. During this period, observe the film removal status at any time. When the film is about to be removed, take the component out of the sub-tank.

[0028] (2) Water washing: Rinse the parts with water to remove the liquid, then soak them in a pure water tank for 30 minutes with the pure water overflowing; after water washing, continue to rinse the parts with a high-pressure water gun with a pressure of 230 bar and a distance of 30 ± 5 cm between the gun head and the parts for 2 minutes; after rinsing, dry them in an 80°C oven.

[0029] (3) Component protection and sandblasting: The sealing surface of the component is protected with black tape, and then the component is peeled and sandblasted with white corundum abrasive WA60# at a pressure of 4 kg / cm. 2 The purpose is to remove residual film and to evenly spray and initially roughen the surface of the component to facilitate further roughening; then, fine sandblasting is performed using white fused alumina abrasive WA24# at a pressure of 3 kg / cm². 2 The purpose is to increase the surface roughness of the parts; after that, use an air gun to blow away the particles on the surface of the parts and remove the protective tape, and wipe off the tape marks with IPA; then use a high-pressure water gun to rinse the parts, with a water gun pressure of 180 bar, the gun head 30±5 cm away from the parts, and a rinsing time of 2 minutes; after rinsing, dry in a 100℃ oven.

[0030] (4) Component protection and spraying: Within 4 hours after drying, protect the sealing surface of the component with yellow spraying tape, set the spraying machine program, the air pressure is 65Psi and the current is 200A, and uniformly spray aluminum onto the spraying surface of the aluminum alloy component so that the surface roughness Rz of the spraying surface is about 180-220μm; after completion, remove the spraying protective tape and check whether there are spraying burrs on the edge; use a high-pressure water gun to rinse the component, the water gun pressure is 230bar, the gun head is 30±5cm away from the component, and the rinsing time is 2min; after rinsing, dry in a 100℃ oven.

[0031] (5) Ultrasonic cleaning: Place the parts in an ultrasonic cleaning tank and use deionized water for ultrasonic cleaning. The deionized water should be in an overflow state, and the ultrasonic intensity should be 6W / in. 2 The cleaning time is 30 minutes; note that parts should not be stacked to prevent friction marks from ultrasonic vibration; after cleaning, dry in a 100℃ oven; then place the parts in the ultrasonic cleaning tank of the clean room and perform ultrasonic cleaning with deionized water. The deionized water should be in an overflow state, and the ultrasonic intensity should be 6W / in. 2 The cleaning time is 15 minutes. After cleaning, high-purity nitrogen (99.999%) is used to purge the surface to remove water droplets from the surface of the parts. The purging pressure is 30±5Psi.

[0032] (6) Post-processing: Transfer the purged parts to a clean drying oven, gradually raise the temperature to 150°C according to the program, dry for 2 hours, and wait for the parts to cool naturally to below 40°C. Take them out, and after passing the quality inspection, vacuum seal the parts with two layers of PE bags. Before packaging, purge the whole part with nitrogen gas at a pressure of 30±5Psi.

[0033] The quality inspection results of Example 1 are as follows: The surface of the cleaned aluminum alloy parts is observed to be clean and free of tantalum nitride contaminants. UV lamp inspection is used to check for impurities and fiber residues on the surface. The surface roughness of the welded surface is measured using a Touch 50 roughness meter, and the surface roughness is 203±12μm (meeting the requirement of a surface roughness of 180-220μm). The surface particle size results for Q-III inspection are: particles with a diameter <0.5μm ≤1 particle / cm. 2 Particles with a diameter of 0.5-1μm ≤ 1 particle / cm 2 Particles with a diameter >1μm are 0 per cm. 2 .

[0034] Comparative Example 1 Comparative Example 1 provides a method for cleaning tantalum nitride contaminants on the surface of an aluminum alloy component.

[0035] The difference between the above comparative example and Example 1 is that: (1) the medicinal solution used in the component protection and immersion steps is as follows: (1) Component protection and immersion in chemicals: First, fill the liquid washing tank with heating rods with water and heat the water to 55°C. Then, place 70% electronic grade nitric acid in the sub-tank. The sub-tank heats the chemical solution to 55°C through heat transfer. Protect the sealing surface of the component with acid and alkali resistant tape. Then, carefully place the component into the sub-tank for immersion. During this period, observe the film removal status at any time. When the film is about to be removed, take the component out of the sub-tank.

[0036] In Comparative Example 1, the concentration of nitric acid and the immersion temperature of the solution were too high. During the immersion process, it was found that the nitric acid evaporated quickly, and the reaction on the surface of the component was more intense in the early stage, resulting in a higher risk factor. As time went on, the reaction on the surface of the component gradually slowed down until the surface of the component basically did not react in the later stage, which ultimately resulted in the tantalum nitride film on the surface of the component not being removed.

[0037] Comparative Example 2 Comparative Example 2 provides a method for cleaning tantalum nitride contaminants on the surface of an aluminum alloy component.

[0038] The difference between the above comparative example and Example 1 is that: (3) the component protection and sandblasting steps are as follows: (3) Component protection and sandblasting: The sealing surface of the component is protected with black tape, and then the component is peeled and sandblasted with white corundum abrasive WA60# at a pressure of 4 kg / cm. 2 Afterwards, use an air gun to blow away particles from the surface of the parts and remove the protective tape. Wipe away the tape residue with an IPA. Then, use a high-pressure water gun to rinse the parts at a pressure of 180 bar, with the nozzle 30±5 cm away from the parts, for a rinsing time of 2 minutes. After rinsing, dry the parts in a 100℃ oven.

[0039] Comparative Example 2 only used WA60# to peel and sandblast the surface of the component. The resulting component could not meet the surface roughness requirements of subsequent molten lamination, which resulted in poor adhesion between the molten lamination layer and the component. When the component was reused, the molten lamination layer on its surface was prone to peeling off.

[0040] Comparative Example 3 Comparative Example 3 provides a method for cleaning tantalum nitride contaminants on the surface of an aluminum alloy component.

[0041] The difference between the above comparative example and Example 1 is that: (3) the component protection and sandblasting steps are as follows: (3) Component protection and sandblasting: The sealing surface of the component is protected with black tape, and then fine sandblasting is performed directly using white corundum abrasive WA24# at a pressure of 6 kg / cm. 2 Afterwards, use an air gun to blow away particles from the surface of the parts and remove the protective tape. Wipe away the tape residue with an IPA. Then, use a high-pressure water gun to rinse the parts at a pressure of 180 bar, with the nozzle 30±5 cm away from the parts, for a rinsing time of 2 minutes. After rinsing, dry the parts in a 100℃ oven.

[0042] Comparative Example 3 uses only WA24# for fine sandblasting of the component surface. In order to ensure that the roughness after fine sandblasting can meet the requirements of subsequent melt spraying, the sandblasting pressure is appropriately increased; however, it was found that the component surface was deformed after sandblasting, and the component could no longer meet the requirements for reuse.

[0043] Comparative Example 4 Comparative Example 4 provides a method for cleaning tantalum nitride contaminants on the surface of an aluminum alloy component.

[0044] The difference between the above comparative example and Example 1 is that (3) after the component protection and sandblasting steps are completed, the melting and spraying are not performed, and the subsequent ultrasonic cleaning is performed directly.

[0045] The surface roughness of the component obtained without spraying in Comparative Example 4 was substandard, and the resulting component could not meet the roughness requirements for reuse.

[0046] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for cleaning tantalum nitride contaminants on the surface of aluminum alloy parts, characterized in that, Includes the following steps: Component protection and chemical immersion, water washing, component protection and sandblasting, component protection and electroblasting, ultrasonic cleaning, post-treatment; Component protection and chemical immersion: The sealing surfaces of the components are pre-protected with acid and alkali resistant tape, and then immersed in a chemical solution at 40-45℃ for 0.5-2 hours. When the contaminant film on the surface of the aluminum alloy components is almost removed, the aluminum alloy components are taken out. The chemical solution is a mixture of 70% nitric acid, N-methylpyrrolidone, and water in a volume ratio of 1:(0.15-0.3):(0.8-1.2). Component protection and sandblasting: The sealing surfaces of the components are protected with black tape, then the components are peeled and sandblasted using WA60# white corundum abrasive at a pressure of 3-5 kg / cm². 2 Then, fine sandblasting is performed using white fused alumina abrasive WA24# at a pressure of 3-4 kg / cm². 2 ; Component protection and spraying: Protect the sealing surface of the component with yellow spraying tape, and uniformly spray aluminum onto the spraying surface of the aluminum alloy component to achieve a surface roughness Rz of 180-220μm.

2. The method for cleaning tantalum nitride contaminants on the surface of aluminum alloy parts according to claim 1, characterized in that, The surface contaminant contains tantalum nitride.

3. The method for cleaning tantalum nitride contaminants on the surface of aluminum alloy parts according to claim 1, characterized in that, In the water washing step, the components are first soaked in pure water for 25-40 minutes, then rinsed with a high-pressure water gun at a pressure of 220-250 bar for 2-3 minutes, and then dried at 75-85°C.

4. The method for cleaning tantalum nitride contaminants on the surface of aluminum alloy parts according to claim 1, characterized in that, After the component protection and sandblasting are completed, the component needs to be rinsed with a high-pressure water gun. The water gun pressure is 180-200 bar, the gun head is 20-40 cm away from the component, and the rinsing time is 2-3 minutes. After rinsing, it is dried at 95-105℃.

5. The method for cleaning tantalum nitride contaminants on the surface of aluminum alloy parts according to claim 1, characterized in that, After the welding process is completed, remove the welding protective tape, and rinse the parts with a high-pressure water gun at a pressure of 220-250 bar, with the gun head 20-40 cm away from the parts, for 2-3 minutes. After rinsing, dry the parts in an oven at 95-105℃.

6. The method for cleaning tantalum nitride contaminants on the surface of aluminum alloy parts according to claim 1, characterized in that, During the ultrasonic cleaning process, the ultrasonic intensity is 4-10 W / in. 2 The time is 30-60 minutes.

7. The method for cleaning tantalum nitride contaminants on the surface of aluminum alloy parts according to claim 1, characterized in that, The post-processing includes drying at a temperature of 140-160℃ for 2-3 hours.