Conductive adhesive degumming method for semiconductor circuit board
Through the method of soaking acid solution and cleaning of oxygen plus argon or nitrogen, the problem of difficult removal of conductive glue residues in semiconductor products is solved, and the protection of metal lines and efficient removal of conductive glue is achieved.
Patent Information
- Application Number
- CN202510341549.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-21
- Publication Date
- 2025-06-20
AI Technical Summary
In the process of producing semiconductor products, it is difficult to effectively remove conductive glue residues, resulting in abnormal subsequent processes and reduced product yields. At the same time, traditional glue removers have serious corrosion to metals.
The acid solution soaking combined with plasma cleaning method is adopted. The specific steps include soaking the circuit board with an acid solution at room temperature, and then performing plasma cleaning of oxygen plus argon or nitrogen not more than 20 sccm.
Effectively removes ACF conductive adhesive residue, reduces corrosion to metal lines, and improves cleaning efficiency and product yield.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of semiconductor manufacturing processes, and particularly relates to a method for removing conductive adhesive from a semiconductor circuit board. Background Art
[0002] A conductive adhesive is an adhesive that has certain electrical conductivity after curing. It usually consists mainly of a matrix resin and conductive fillers, i.e., conductive particles. Through the bonding action of the matrix resin, the conductive particles are combined together to form a conductive path, realizing the conductive connection between the adhered materials on the wiring substrate.
[0003] During the production process of semiconductor products, sometimes due to improper process operations, machine abnormalities, or various other reasons, the products / semi-finished products need to be reworked to reduce the losses caused by scrapping. When reworking, the primary task is to select an appropriate chemical solution to remove part of the conductive adhesive. However, the conductive adhesive in the concave and convex parts of some circuits and the grooves with relatively thin line widths is often difficult to remove and is prone to residue. These conductive adhesive residues will cause abnormalities in subsequent processes or a decrease in product yield.
[0004] Traditional ethanolamine / organic compound de-bonding formulations can remove most of the conductive adhesive, but they cause relatively heavy corrosion to metals. Especially for grooves and depressions, due to the difficult removal of residual conductive adhesive and the long residence time of the de-bonding agent, the metal corrosion is particularly serious.
[0005] In addition to wet cleaning, dry plasma cleaning is generally used in semiconductor cleaning processes to effectively remove organic substances on the substrate. Dry cleaning for removing organic substances uses plasma oxygen to oxidize and then remove the organic substances remaining on the chip surface. Such a process is not likely to affect inorganic substances such as metals or dielectric layers. However, due to the presence of conductive substances (non-organic substances, usually conductive metal materials) in the composition of the conductive adhesive, pure oxygen plasma cannot be used for de-bonding treatment. However, if argon or nitrogen with a strong physical bombardment force is used in the plasma for the cleaning process, it may cause corrosion and other effects on inorganic substances such as metals or dielectric layers. Therefore, a new process method is needed to overcome this problem. Summary of the Invention
[0006] To solve the deficiencies of the prior art, the present invention provides a method for removing conductive adhesive from a semiconductor circuit board. This method causes little corrosion to metal circuits or patterns such as copper and nickel, greatly reducing the damage to the metal on the circuit substrate.
[0007] To achieve the above technical objectives, the technical solution of the present invention is a method for removing conductive adhesive from a semiconductor circuit board, including the following steps: 1) Soaking: Soak the circuit board with an acid solution at room temperature; 2) Plasma cleaning: The plasma cleaning conditions are oxygen plus argon or nitrogen not exceeding 20 sccm.
[0008] Preferably, the acid solution used in the soaking in step 1) is selected from sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, metaphosphoric acid, sulfonic acid and its derivatives, hydrofluoric acid, hydrobromic acid, formic acid, acetic acid, propionic acid, n-butyric acid, and isobutyric acid.
[0009] Preferably, the acid solution used in the soaking in step 1) is any one of phosphoric acid, acetic acid, sulfuric acid, and hydrochloric acid.
[0010] Preferably, the soaking time in step 1) is no more than 5 minutes.
[0011] Preferably, the plasma cleaning conditions in step 2) are oxygen plus argon at 5 - 15 sccm, or oxygen plus nitrogen at 5 - 15 sccm.
[0012] Preferably, the plasma cleaning time in step 2) is 5 to 15 minutes.
[0013] The present invention improves the cleaning method, and adds a dry cleaning process after cleaning with an acid solution to achieve effective cleaning, significantly reduce metal corrosion, and improve the yield.
[0014] The present invention can effectively remove the ACF conductive adhesive without damaging metal lines or patterns such as copper and nickel on the circuit board, and has high efficiency, can peel off the conductive adhesive in a short time, and improve the cleaning efficiency. Specific Embodiments
[0015] To better understand the present invention, the technical solutions of the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to these embodiments.
[0016] Comparative Examples 1 - 4
[0017] Traditional ethanolamine / organic compound was used to remove the adhesive, and the results are shown in Table 1.
[0018] Table 1
[0019]
[0020] Comparative Examples 5 - 8
[0021] Compared with the traditional ethanolamine / organic compound adhesive removal formula, the one-stage acid solution was used to test the adhesive removal situation at room temperature (25°C), and the results are shown in Table 2.
[0022] Table 2
[0023]
[0024] Examples 1 - 8
[0025] Use a one-stage acid solution at room temperature (25 °C) for a 3-minute degumming process, and use the plasma cleaning conditions of the method of the present invention to clean for 10 minutes. The ACF conductive adhesive on the wafer can be completely cleaned. The cleaning conditions and copper corrosion results are shown in Table 3. The results show that the copper corrosion is less severe than that after the degumming process in the comparative example.
[0026] Note: If only oxygen is used for plasma cleaning, even after 30 minutes of cleaning, the ACF conductive adhesive on the wafer cannot be completely cleaned.
[0027] Table 3
[0028]
[0029]
[0030] Comparative Examples 9-18
[0031] In addition, use a one-stage acid solution at room temperature (25 °C) for a 3-minute degumming process, and use plasma cleaning. The ACF conductive adhesive on the wafer can be completely cleaned. The cleaning conditions and copper corrosion results are shown in Table 4. The results of Comparative Examples 9-14 show that at the same cleaning time, after plasma cleaning with argon or nitrogen at a flow rate of 25 sccm or greater, the copper corrosion becomes more severe than the results in Table 3. It can be seen that if excessive argon or nitrogen is used, metal corrosion will occur due to its strong physical bombardment force.
[0032] The results of Comparative Examples 15-18 show that using the plasma cleaning conditions of the method of the present invention but increasing the cleaning time to 20 minutes and 25 minutes, the copper corrosion becomes more severe than the results of the 10-minute cleaning in the examples of Table 3. It can be seen that the cleaning time of plasma cleaning cannot be too long to avoid more serious metal corrosion.
[0033] Table 4
[0034]
[0035]
[0036] The present invention mainly uses oxygen in the plasma cleaning machine and adds no more than 20 sccm of argon or nitrogen for the relevant cleaning process. Under such conditions, the corrosion of the metal by the acid solution can be reduced under a shorter acid solution immersion time, and the removal effect of the ACF conductive adhesive can be achieved after plasma cleaning, and there is a better cleaning yield.
[0037] After the cleaning with an acid solution, a dry cleaning process is added to achieve effective cleaning, significantly reduce metal corrosion, and improve the yield. Without damaging metal lines or patterns such as copper and nickel on the circuit board, the present invention can effectively remove the ACF conductive adhesive, and has high efficiency, can peel off the conductive adhesive in a short time, and improve the cleaning efficiency and process yield.
[0038] The above-described embodiments are only preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.
Claims
1. A method for debonding conductive adhesive for semiconductor circuit boards, characterized in that: The conductive adhesive debonding method comprises the following steps: 1) soaking: soaking the circuit board with an acid solution at room temperature; 2) plasma cleaning: the plasma cleaning condition is oxygen plus argon or nitrogen not more than 20sccm.
2. The method for debonding a conductive adhesive for a semiconductor circuit board according to claim 1, characterized in that: The acid solution used in the soaking in step 1) is selected from sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, metaphosphoric acid, sulfonic acid and its derivatives, hydrofluoric acid, hydrobromic acid, formic acid, acetic acid, propionic acid, n-butyric acid, and isobutyric acid.
3. The method for debonding a conductive adhesive for a semiconductor circuit board according to claim 1, characterized in that: The acid solution used in the soaking step 1) is any one of phosphoric acid, acetic acid, sulfuric acid and hydrochloric acid.
4. The method for debonding conductive adhesive for semiconductor circuit boards according to claim 1, characterized in that: The soaking time in step 1) is no more than 5 minutes.
5. The method for debonding conductive adhesive for semiconductor circuit boards according to claim 1, characterized in that: The plasma cleaning condition in step 2) is oxygen plus argon 5-15 sccm, or oxygen plus nitrogen 5-15 sccm.
6. The method for debonding conductive adhesive for semiconductor circuit boards according to claim 1, characterized in that: The plasma cleaning time in step 2) is 5 to 15 minutes.