Ultra-high cleanliness cleaning method for semiconductor components

Abstract

The present invention belongs to the technical field of surface cleaning of metals and their products, and in particular relates to an ultra-high cleanliness cleaning technology for semiconductor components and its application. The ultra-high cleanliness cleaning technology for semiconductor components provided by the present invention combines ultrasonic cleaning and degreasing into one. By adding a cleaning agent during ultrasonic cleaning, ultrasonic cleaning and degreasing are performed simultaneously, not only can the effect of early ultrasonic cleaning be achieved, but lipids on the surface of semiconductor components can also be removed, eliminating the need for a separate degreasing step. In addition, the acid etching step is eliminated during the acid etching and pickling stages, and a higher concentration of nitric acid is used to directly clean the semiconductor components, achieving the effects of acid etching and nitric acid cleaning at the same time. The changes in the two greatly simplify the process steps and reduce the consumption of raw materials, thereby greatly improving the cleaning efficiency and reducing production costs.

Description

Technical Field

[0001] The invention belongs to the technical field of metal product surface cleaning, and in particular relates to an ultra-high cleanliness cleaning method for semiconductor components. Background Art

[0002] With the development of the semiconductor industry, semiconductor applications are becoming increasingly widespread. Different application areas have different requirements for semiconductor surface cleanliness. Generally speaking, semiconductors generally have very high cleanliness requirements. If components that do not meet the cleanliness standards are used, it will cause wafer contamination and lead to serious economic losses. Therefore, it is necessary to remove dust particles, oil, dirt, metal ions and other contaminants from the surface of the components to ensure the cleanliness of the components.

[0003] To this end, the prior art discloses a process for cleaning semiconductor aluminum alloy parts. This process sequentially performs ultrasonic cleaning, water immersion cleaning, degreasing, water immersion cleaning, acid etching, water immersion cleaning, nitric acid immersion, water immersion cleaning, water spray rinsing, hot water overflow cleaning, nitrogen drying, and dust-free packaging on the semiconductor aluminum alloy parts to remove dust particles, metal ions, oil stains, dirt, and other contaminants from the surfaces of the semiconductor aluminum alloy parts, thereby achieving a clean effect. However, the above process uses immersion cleaning after all chemical treatments, and the water used for cleaning is not pure water, which is not conducive to good impurity removal. In addition, the process uses 20% nitric acid immersion after acid etching with 3% hydrofluoric acid and 20% nitric acid, which results in complicated cleaning steps. Therefore, it is necessary to develop an ultra-high cleanliness cleaning method for semiconductor parts with better cleaning effect and simpler steps and processes. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to overcome the defects of the existing semiconductor cleaning process, such as poor impurity removal effect and complicated process steps.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The present invention provides a method for cleaning semiconductor components with ultra-high cleanliness, comprising the following steps:

[0007] The semiconductor components are sequentially subjected to ultrasonic degreasing cleaning, primary pure water overflow cleaning, pickling, secondary pure water overflow cleaning, pure water high-pressure washing, hot pure water overflow cleaning, and inert gas drying; wherein,

[0008] The ultrasonic degreasing and cleaning step uses a cleaning agent with a concentration of 12% v / v to 18% v / v, wherein the cleaning agent comprises potassium pyrophosphate and potassium tetraborate;

[0009] The pickling step is to use a 50% v / v nitric acid aqueous solution for cleaning for 3 to 5 minutes.

[0010] Optionally, in the ultrasonic degreasing and cleaning step, the semiconductor component is first immersed in the cleaning agent for 2 to 3 minutes, and then ultrasonically cleaned for 5 to 10 minutes.

[0011] Optionally, in the ultrasonic degreasing cleaning step, the temperature of the cleaning agent is 50-55° C., the ultrasonic frequency is 35-45 KHz, and the current is 4.5-6.5A.

[0012] Optionally, the time for the pure water overflow cleaning is 2 to 5 minutes, and the pure water is replaced when the copper content in the pure water is greater than 30 ppb.

[0013] Optionally, in the pickling step, the nitric acid aqueous solution is replaced when the copper content in the nitric acid aqueous solution is greater than 10 ppm.

[0014] Optionally, the secondary pure water overflow cleaning time is 2 to 5 minutes, and the pure water is replaced when the copper content in the pure water is greater than 30 ppb.

[0015] Optionally, in the pure water high-pressure flushing step, the water pressure is 100 to 1000 PSI, and the water spraying distance is 10 to 20 cm.

[0016] Optionally, in the hot pure water overflow cleaning step, the water temperature is 40-45° C., the cleaning time is 3-5 minutes, and the water quality is ≥2 MΩ.

[0017] Optionally, in the inert gas drying step, the inert gas is filtered using a filter with a pore size of less than 0.01 μm before drying the semiconductor component.

[0018] Optionally, the above-mentioned ultra-high cleanliness cleaning method for semiconductor components further includes a dust-free packaging step: placing the semiconductor components dried by the inert gas in a clean room of Class 1000 or above for vacuum packaging.

[0019] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0020] 1. The ultra-high cleanliness cleaning method for semiconductor components provided by the embodiment of the present invention combines ultrasonic cleaning and degreasing into one. By adding a cleaning agent during ultrasonic cleaning, ultrasonic cleaning and degreasing are performed simultaneously. This not only achieves the effect of early ultrasonic cleaning, but also removes lipids on the surface of semiconductor components, eliminating the need for a separate degreasing step. In addition, the acid etching step is omitted during the acid etching and pickling stages, and a higher concentration of nitric acid is used to directly clean the semiconductor components, achieving the effects of acid etching and nitric acid cleaning at the same time. The changes in the two greatly simplify the process steps and reduce the consumption of raw materials, thereby greatly improving the cleaning efficiency and reducing production costs.

[0021] 2. The ultra-high cleanliness cleaning technology for semiconductor components provided by the present invention monitors the content of substances in the tank liquid in each step of the cleaning process in real time, especially the copper content, and monitors the cleaning liquid based on the copper content. When the copper content in the tank liquid exceeds 10ppm, the cleaning liquid is replaced; when the copper content exceeds 30ppb, pure water is replaced. The timely replacement of the cleaning liquid avoids repeated excessive cleaning causing contamination of the cleaning liquid, which results in incomplete cleaning of pollutants attached to the surface of semiconductor components during the cleaning process, thereby ensuring the high cleanliness of the cleaning of semiconductor components.

[0022] 3. The ultra-high cleanliness cleaning technology for semiconductor components provided by the present invention can be widely used in the surface cleaning of various semiconductor components, greatly facilitating the production and scientific research of enterprises, and greatly improving the efficiency of production and scientific research of enterprises. DETAILED DESCRIPTION

[0023] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0024] If specific experimental procedures or conditions are not specified in the examples, they can be performed according to the conventional experimental procedures or conditions described in the literature in the field. Reagents or instruments used without manufacturer's indication are all commercially available conventional reagents. In the examples of the present invention, ISOPREP 49L cleaning agent is manufactured by MacDermid Corporation in the United States. The cleaning agent is prepared with purified water at a volume ratio of 100:15 to a 15% v / v ratio. All chemicals used in the examples are analytical grade or higher, and the water used is pure water or higher.

[0025] In this embodiment, the inert gas used is nitrogen. The cleaning tank is dedicated to cleaning a specific series of materials. For example, AL 6061 aluminum parts should be cleaned on a process line dedicated to cleaning 6000 series aluminum materials. Components connected to copper-containing materials (such as copper pipes) (such as welding, brazing, or molding) must not be processed in the bath. During the entire process, latex gloves, masks, and other protective equipment must be worn to protect personal safety and prevent contamination of the parts by the external environment.

[0026] An embodiment of the present invention provides an ultra-high cleanliness cleaning technology for semiconductor components, comprising the following steps:

[0027] Step 1: Place the semiconductor components in an ultrasonic cleaning tank filled with cleaning solution. The concentration of the tank solution is 15% v / v ISOPREP. The cleaning temperature is 50-55°C and the cleaning time is 5-10 minutes.

[0028] Step 2: Place the semiconductor components in pure water for overflow cleaning, the cleaning time is 2 minutes;

[0029] Step 3: Place the parts in nitric acid for cleaning at a concentration of 50% v / v for 3 to 5 minutes. When the copper content in the cleaning solution is greater than 10 ppm, replace the nitric acid and continue cleaning.

[0030] Step 4: Place the parts in pure water for overflow cleaning, the cleaning time is 2 minutes;

[0031] Step 5: Rinse the parts with a water gun at a pressure of 100 to 1000 PSI and a spray distance of 11 to 19 cm.

[0032] Step 6: Place in hot pure water for overflow cleaning, water quality ≥ 2MΩ, water washing temperature 39-45℃, washing time 3-5min;

[0033] Step 7: Blow dry with nitrogen gas filtered with a pore size of less than 0.01 μm;

[0034] Step 8: Vacuum pack in a Class 1000 or higher clean room, and use Class 1000 or higher dust-free cloth and PE bags to pack the cleaned semiconductor components.

[0035] When using pure water for cleaning, if the copper content in the cleaning solution is greater than 30ppb, replace the pure water.

[0036] Example 1

[0037] Cleaning of semiconductor components using uniform gas discs in ultra-high vacuum environments:

[0038] Step 1: Place the semiconductor components in an ultrasonic cleaning tank filled with cleaning solution for cleaning. The ultrasonic frequency is 35KHz, the current is 4.5A, the bath concentration is 15% v / v ISOPREP, the cleaning temperature is 50°C, and the cleaning time is 5 minutes.

[0039] Step 2: Place the semiconductor components in pure water for overflow cleaning, the cleaning time is 2 minutes;

[0040] Step 3: Clean the parts in nitric acid at a concentration of 50% v / v for 3 minutes.

[0041] Step 4: Place the parts in pure water for overflow cleaning, the cleaning time is 2 minutes;

[0042] Step 5: Rinse the parts with a water gun at a pressure of 200 PSI and a spray distance of 11 cm.

[0043] Step 6: Place in hot pure water for overflow cleaning, water quality ≥ 2MΩ, water washing temperature 39℃, water washing time 3min;

[0044] Step 7: Blow dry with nitrogen gas filtered through a filter with a pore size of 0.01 μm;

[0045] Step 8: Vacuum pack in a Class 1000 clean room and use Class 1000 dust-free cloth to pack the cleaned semiconductor components.

[0046] Example 2

[0047] Cleaning of semiconductor components covered by lids used in ultra-high vacuum environments:

[0048] Step 1: Place the semiconductor components in an ultrasonic cleaning tank filled with cleaning solution for cleaning. The ultrasonic frequency is 45KHz, the current is 6.5A, the bath concentration is 15% v / v ISOPREP, the cleaning temperature is 55°C, and the cleaning time is 10 minutes.

[0049] Step 2: Place the semiconductor components in pure water for overflow cleaning, the cleaning time is 2 minutes;

[0050] Step 3: Clean the parts in nitric acid at a concentration of 50% v / v for 5 minutes.

[0051] Step 4: Place the parts in pure water for overflow cleaning, the cleaning time is 2 minutes;

[0052] Step 5: Rinse the parts with a water gun at a pressure of 900 PSI and a spray distance of 19 cm.

[0053] Step 6: Place in hot pure water for overflow cleaning, water quality ≥ 2MΩ, water washing temperature is 45℃, and water washing time is 5 minutes;

[0054] Step 7: Blow dry with nitrogen gas filtered through a filter with a pore size of 0.01 μm;

[0055] Step 8: Vacuum packaging is performed in a Class 1000 clean room, and Class 1000 PE bags are used to package the cleaned semiconductor components.

[0056] Test example

[0057] The cleanliness test of the semiconductor components after cleaning in the embodiment was carried out, and the test results are as follows:

[0058] The cleanliness test of the semiconductor components after cleaning in Example 1 is shown in Table 1:

[0059] Table 1

[0060]

[0061]

[0062] The cleanliness test of the semiconductor components after cleaning in Example 2 is shown in Table 2:

[0063] Table 2

[0064]

[0065]

[0066] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for cleaning semiconductor components with ultra-high cleanliness, characterized in that: The following steps are involved: The semiconductor components are sequentially subjected to ultrasonic degreasing cleaning, primary pure water overflow cleaning, pickling, secondary pure water overflow cleaning, pure water high-pressure washing, hot pure water overflow cleaning, and inert gas drying; wherein, The ultrasonic degreasing cleaning step uses a cleaning agent with a concentration of 12% v / v to 18% v / v, wherein the cleaning agent includes potassium pyrophosphate and potassium tetraborate. In the ultrasonic degreasing cleaning step, the semiconductor component is first immersed in the cleaning agent for 2 to 3 minutes, and then ultrasonically cleaned for 5 to 10 minutes. The time for the primary pure water overflow and / or the secondary pure water overflow cleaning is 2 to 5 minutes, and the pure water is replaced when the copper content in the pure water is greater than 30 ppb. The pickling step comprises cleaning with a nitric acid aqueous solution having a concentration of 50% v / v for 3 to 5 minutes. In the pickling step, the nitric acid aqueous solution is replaced when the copper content in the nitric acid aqueous solution is greater than 10 ppm.

2. The method for ultra-high cleanliness cleaning of semiconductor components according to claim 1, wherein: In the ultrasonic degreasing cleaning step, the temperature of the cleaning agent is 50-55° C., the ultrasonic frequency is 35-45 KHz, and the current is 4.5-6.5A.

3. The ultra-high cleanliness cleaning method for semiconductor components according to claim 1, characterized in that: In the pure water high-pressure flushing step, the water pressure is 100 to 1000 PSI, and the water spraying distance is 10 to 20 cm.

4. The ultra-high cleanliness cleaning method for semiconductor components according to claim 1, characterized in that: In the hot pure water overflow cleaning step, the water temperature is 40-45° C., the cleaning time is 3-5 minutes, and the water quality is ≥2MΩ.

5. The ultra-high cleanliness cleaning method for semiconductor components according to claim 1, characterized in that: In the inert gas drying step, the inert gas is filtered using a filter with a pore size of less than 0.01 μm and then the semiconductor component is dried.

6. The ultra-high cleanliness cleaning method for semiconductor components according to any one of claims 1 to 5, characterized in that: The method further comprises a dust-free packaging step: placing the semiconductor components dried by the inert gas in a class 1000 or higher clean room for vacuum packaging.

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