Semiconductor electrochemical gold etching solution and etching method thereof
By using an electrochemical gold etching solution and an applied current, the problems of uncontrollable etching rate and poor safety in wet etching technology were solved, achieving controllable etching rate and surface uniformity of elemental gold, and improving the stability and safety of the etching process.
Patent Information
- Application Number
- CN202311275177.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-28
- Publication Date
- 2026-06-05
- Estimated Expiration
- 2043-09-28
AI Technical Summary
Existing wet etching technology has an uncontrollable etching rate for elemental gold, which can easily lead to linewidth loss and residue. Furthermore, conventional etching solutions are unstable and have poor safety.
An electrochemical gold etching solution composed of inorganic acids, metal salts, halides, surfactants, detergents, and defoamers is used. The etching process is controlled by an applied current, and the composition and conditions of the etching solution are adjusted to achieve controllable etching rate and uniform surface.
This method achieves controllable etching rate of elemental gold, resulting in a uniform surface with no color difference, thus improving the stability and safety of the etching process.
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Abstract
Description
Technical Field
[0001] This invention relates to the intersection of wet electronic chemicals and semiconductor integrated circuits. Specifically, it relates to a semiconductor electrochemical gold etching solution and its etching method, in which an electrochemical reaction occurs on the wafer under an applied current to etch elemental gold on the surface. Technical Background
[0002] Due to the rapid development of the internet, smartphones, new energy vehicles, 5G, and metaverse in recent years, the demand for semiconductor chips in the fast-evolving consumer and information sectors is increasing, and the requirements are becoming more stringent. Consequently, chip manufacturing processes are resulting in smaller linewidths, stronger high-voltage breakdown resistance, faster signal transmission, and lower power consumption. Signal transmission on chips primarily relies on metal or alloy layers. Different metals exhibit varying characteristics in signal transmission, resistance, heat dissipation, thermal expansion coefficients, and ductility. Gold, with its low resistance, excellent heat dissipation, low signal loss, fast transmission, and resistance to oxidation, is extremely suitable for use in high-end chip metal conductors. For gold thin films deposited using PVD, ALD, and other technologies, wet etching is commonly used in the circuit formation process. While fast and low-cost, conventional wet etching suffers from uncontrollable speed, etching only unmasked areas and easily leading to residue and linewidth loss. Furthermore, because gold is extremely inert, typical wet etching requires strong oxidants, which cause instability, safety concerns, and pollution in the etching solution. Therefore, a controllable, high-rate, stable, and safe etching process was developed.
[0003] Gold etching solution becomes both necessary and urgent.
[0004] Based on this, the present invention utilizes a stable and safe etching solution, applies an external current to the wafer, and immerses it in the etching solution to control the etching process electrochemically. The etching solution in this invention does not need to be oxidizing; simply applying a voltage to the wafer to create a certain current density between the wafer and the etching solution is sufficient for directional etching, and the etching rate is controllable. Furthermore, by adjusting the composition, pH value, content, and etching conditions of the electrochemical gold etching solution, and by utilizing the bridging effect of halogens in polyhalides on gold, excellent results such as fast etching rate, controllable etching thickness, and uniform surface can be achieved for elemental gold on semiconductor wafers. Summary of the Invention
[0005] In view of this, the present invention utilizes an electrochemical gold etching solution composed of inorganic acids, metal salts, halides, surfactants, detergents, and defoamers. The anode and cathode of a semiconductor wafer are immersed in the electrochemical gold etching solution, and elemental gold is etched electrochemically under a constant current density. By adjusting the composition, pH value, content, and etching conditions of the electrochemical gold etching solution, excellent effects such as fast etching rate, controllable etching thickness, and uniform surface are achieved on the semiconductor wafer.
[0006] The purpose of this invention is to provide a semiconductor electrochemical gold etching solution and its etching method.
[0007] To achieve the above objectives, the present invention provides a semiconductor electrochemical gold etching solution and its etching method:
[0008] Semiconductor electrochemical gold etching solution contains inorganic acids, metal salts, halides, surfactants, detergents, defoamers, and pure water.
[0009] The inorganic acid in the semiconductor electrochemical gold etching solution is one or more of phosphoric acid, nitric acid, sulfuric acid, hydrochloric acid, hydrofluoric acid, etc., and the total mass content of the inorganic acid in the electrochemical gold etching solution is 5-50%, preferably 10%-40%, and the pH value of the electrochemical gold etching solution is less than 1.
[0010] The metal salt in the semiconductor electrochemical gold etching solution is one or more of sodium phosphate / potassium, sodium nitrate / potassium, sodium sulfate / potassium, sodium chloride / potassium, sodium fluoride / potassium, etc., and the total mass content of the metal salt in the electrochemical gold etching solution is 1-10%, preferably 1%-5%.
[0011] The halides in the semiconductor electrochemical gold etching solution are one or more of the following: polyhalogenated hexabromocyclododecane, perfluorooctane sulfonyl compounds, pentachlorobenzoic acid, etc., and the total mass content of the halides in the electrochemical gold etching solution is 0.1-10%.
[0012] The surfactant in the semiconductor electrochemical gold etching solution is a cationic surfactant, mainly one or more of dodecylammonium chloride, dimethylammonium bromide, etc., and the total mass content of the surfactant in the electrochemical gold etching solution is 0.01-1%.
[0013] The detergent in the semiconductor electrochemical gold etching solution is one or more of ethanol, isopropanol, acetone, etc., and the total mass content of the detergent in the electrochemical gold etching solution is 0.1-5%.
[0014] The defoamer in the semiconductor electrochemical gold etching solution is one or more of polyether-type defoamers such as GP, GPE, and GPES, with GPE defoamer being preferred, and the total mass content is 0.01-1%.
[0015] Etching method of semiconductor electrochemical gold etching solution: Electrochemical gold etching solution can only etch elemental gold on semiconductors when there is current flowing through it. The semiconductor wafer must be immersed in the electrochemical gold etching solution as the anode, and a cathode with the same area as the anode must be immersed in the electrochemical gold etching solution. Current is simultaneously applied to the anode and cathode, and the electrochemical gold etching solution is in a disturbed state to etch elemental gold.
[0016] In the above etching method: the anode and cathode need to be placed in the electrochemical gold etching solution in parallel relative to each other, the distance between the anode and cathode needs to be within 5cm, the current density on the anode is 0.1-5ASD, the stirring rate of the electrochemical gold etching solution is 30-300r / min, and the working temperature of the electrochemical gold etching solution is 20-60℃.
[0017] The advantages and beneficial effects of this invention are as follows: First, no oxidant needs to be added to the etching solution, ensuring the stability and safety of the etching solution production, transportation, etching, and waste liquid treatment processes; Second, gold can only be etched when an electric current is applied to the wafer and the etching solution, and the etching solution itself does not directly etch gold, so the etching process can be controlled by the presence or absence of current; Third, by adjusting the composition, pH value, content, and etching conditions of the electrochemical gold etching solution, rapid etching of elemental gold on semiconductor wafers can be achieved, while simultaneously achieving excellent results of uniform etching surface without color difference. Detailed Implementation
[0018] To better understand the present invention, the present invention will be further described in detail below, but the scope of protection of the present invention is not limited to the scope shown in the embodiments.
[0019] Comparative Example 1
[0020] Based on the traditional iodine and potassium iodide system, a gold etching solution is prepared using elemental iodine, potassium iodide, and pure water.
[0021] Weigh 10 parts potassium iodide and add it to 88 parts pure water until completely dissolved; then weigh 2 parts elemental iodine and add it to the solution, mixing thoroughly to form a gold etching solution. Use a four-probe resistance meter to test the thickness of the wafer with the gold structure layer to determine the gold thickness. Pour the prepared gold etching solution into the etching unit, immerse the wafer in the solution, set the stirring speed to 180 rpm, the etching temperature to 25°C, and the etching time to 30 seconds. Immediately after etching, rinse with plenty of deionized water and dry with nitrogen. Finally, use a four-probe resistance meter to test the gold thickness and observe for any color difference.
[0022] As shown in Table 1, the thickness before etching is... After etching under the above conditions, the thickness of the gold on the wafer is [missing information]. Before etching, the wafer was uniform with no color difference; after etching, the surface became rough and uneven, with color variations. Based on calculations, the etching rate was... The aforementioned gold etching solution has a fast etching rate, but the etching process is uncontrollable and can only be used in processes where the entire layer of metal is etched.
[0023] Comparative Example 2
[0024] In a semiconductor electrochemical gold etching solution and etching method thereof, an etching solution containing inorganic acid, metal salt, halide, surfactant, detergent, defoamer, and pure water is prepared.
[0025] Weigh 20 parts of 50% hydrofluoric acid and add it to 71.8 parts of pure water. Mix well and cool to room temperature. Then, weigh out 3 parts of sodium fluoride, 3 parts of ammonium fluoride, 2 parts of isopropanol, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix well to form an electrochemical gold etching solution. Pour the prepared gold etching solution into the unit tank of the machine. Immerse a 6-inch wafer as the anode in the gold etching solution and use a copper sheet of the same size as the cathode. Set the current density to 0 ASD, the stirring speed to 180 r / min, the etching temperature to 25℃, and the etching time to 30 minutes. Immediately after the etching time, rinse with plenty of deionized water and dry with nitrogen. Finally, use a four-probe resistance meter to test the gold thickness and observe for any color difference.
[0026] As shown in Table 1, the thickness before etching is... Under the above conditions, etching was performed for 30 minutes at 0 current density, resulting in a thickness of [missing information]. According to calculations, the etching rate is Due to fluctuations in instrument detection, it can be concluded that the etching solution hardly etches gold under no applied current density, and the wafer surface is smooth and colorless before and after etching.
[0027] Comparative Example 3
[0028] In a semiconductor electrochemical gold etching solution and etching method thereof, an etching solution containing inorganic acid, halide, surfactant, detergent, defoamer, and pure water is prepared.
[0029] Weigh 20 parts of 50% hydrofluoric acid and add it to 74.8 parts of pure water. Mix well and cool to room temperature. Then, weigh out 3 parts of a mixture of pentachlorobenzoic acid and 2 parts of isopropanol, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution, mixing well to form an electrochemical gold etching solution. Pour the prepared gold etching solution into the unit tank of the machine. Immerse a 6-inch wafer as the anode in the gold etching solution and use a copper sheet of the same size as the cathode. Adjust the current density to 0.1 ASD, set the stirring speed to 180 r / min, the etching temperature to 25℃, and the etching time to 1 minute. Immediately after the etching time, rinse with plenty of deionized water and dry with nitrogen. Finally, use a four-probe resistance meter to test the gold thickness and observe for any color difference.
[0030] As shown in Table 1, the thickness before etching is... After etching for 1 minute under the above conditions, the thickness after etching is... According to calculations, the etching rate is The etched surface has raised textures, but there is basically no color difference.
[0031] Comparative Example 4
[0032] In a semiconductor electrochemical gold etching solution and etching method thereof, an etching solution containing inorganic acid, metal salt, surfactant, detergent, defoamer, and pure water is prepared.
[0033] Weigh 20 parts of 50% hydrofluoric acid and add it to 74.8 parts of pure water. Mix well and cool to room temperature. Then, weigh out 3 parts of sodium fluoride, 2 parts of isopropanol, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix well to form an electrochemical gold etching solution. Pour the prepared gold etching solution into the unit tank of the machine. Immerse a 6-inch wafer as the anode in the gold etching solution and use a copper sheet of the same size as the cathode. Adjust the current density to 0.1 ASD, set the stirring speed to 180 r / min, the etching temperature to 25℃, and the etching time to 1 minute. Immediately after the etching time, rinse with plenty of deionized water and dry with nitrogen. Finally, use a four-probe resistance meter to test the gold thickness and observe for any color difference.
[0034] As shown in Table 1, the thickness before etching is... After etching for 1 minute under the above conditions, the thickness after etching is... According to calculations, the etching rate is The surface is uneven after etching, with slight color differences.
[0035] Comparative Example 5
[0036] In a semiconductor electrochemical gold etching solution and etching method thereof, an etching solution containing inorganic acid, metal salt, halide, surfactant, detergent and pure water is prepared.
[0037] Weigh 20 parts of 50% hydrofluoric acid and add it to 71.9 parts of pure water. Mix well and cool to room temperature. Then, weigh out 3 parts of sodium fluoride, 3 parts of a mixture of pentachlorobenzoic acid and 2 parts of isopropanol, and 0.1 parts of dimethylammonium bromide and add them to the above solution. Mix well to form an electrochemical gold etching solution. Pour the prepared gold etching solution into the unit tank of the machine. Immerse a 6-inch wafer as the anode in the gold etching solution and use a copper sheet of the same size as the cathode. Adjust the current density to 0.1 ASD, set the stirring speed to 180 r / min, the etching temperature to 25℃, and the etching time to 1 minute. Immediately after the etching time, rinse with plenty of deionized water and dry with nitrogen. Finally, use a four-probe resistance meter to test the gold thickness and observe for any color difference.
[0038] As shown in Table 1, the thickness before etching is... After etching for 1 minute under the above conditions, the thickness after etching is... According to calculations, the etching rate is After etching, there are localized protrusions on the surface, but no color difference; there is a lot of foam during the etching process, and air bubbles are adsorbed on the wafer surface.
[0039] Comparative Example 6
[0040] In a semiconductor electrochemical gold etching solution and etching method thereof, an etching solution containing metal salt, halide, surfactant, detergent, defoamer and pure water is prepared.
[0041] In 91.8 parts of pure water, 3 parts of sodium fluoride, 3 parts of a mixture of pentachlorobenzoic acid and 2 parts of isopropanol, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP were weighed out and added to the above solution and mixed evenly to form an electrochemical gold etching solution. The prepared gold etching solution was poured into the unit tank of the machine, and a 6-inch wafer was immersed in the gold etching solution as the anode. A copper sheet of the same size was used as the cathode. The current density was adjusted to 0.1 ASD, the stirring speed was set to 180 r / min, the etching temperature was 25℃, and the etching time was 1 minute. After the etching time was completed, the wafer was immediately rinsed with a large amount of deionized water and dried with nitrogen. Finally, the gold thickness was measured using a four-probe resistance meter, and the presence of color difference was observed.
[0042] As shown in Table 1, the thickness before etching is... After etching for 1 minute under the above conditions, the thickness after etching is... According to calculations, the etching rate is The pH value is greater than 7, making it alkaline. After etching, there are localized protrusions on the surface, and the color changes from golden yellow to brown.
[0043] Example 1
[0044] In a semiconductor electrochemical gold etching solution and etching method thereof, an etching solution containing inorganic acid, metal salt, halide, surfactant, detergent, defoamer, and pure water is prepared.
[0045] Weigh 20 parts of 50% hydrofluoric acid and add it to 71.8 parts of pure water. Mix well and cool to room temperature. Then, weigh out 3 parts of sodium fluoride, 3 parts of a mixture of pentachlorobenzoic acid and 2 parts of isopropanol, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix well to form an electrochemical gold etching solution. Pour the prepared gold etching solution into the unit tank of the machine. Immerse a 6-inch wafer as the anode in the gold etching solution and use a copper sheet of the same size as the cathode. Adjust the current density to 0.1 ASD, set the stirring speed to 180 r / min, the etching temperature to 25℃, and the etching time to 1 minute. Immediately after the etching time, rinse with plenty of deionized water and dry with nitrogen. Finally, use a four-probe resistance meter to test the gold thickness and observe for any color difference.
[0046] As shown in Table 1, the thickness before etching is... The thickness after etching under the above conditions is According to calculations, the etching rate is Furthermore, the etched surface is uniform and has no color difference.
[0047] Example 2
[0048] The preparation steps and detection methods for the electrochemical gold etching solution are the same as in Example 1.
[0049] Weigh 20 parts of 98% concentrated sulfuric acid and add it to 71.8 parts of pure water. Mix thoroughly and cool to room temperature. Then, weigh out 3 parts of sodium sulfate, 3 parts of a mixture of pentachlorobenzoic acid and 2 parts of isopropanol, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix thoroughly to form an electrochemical gold etching solution. The current density is 0.1 ASD, the stirring speed is 180 r / min, the etching temperature is 25℃, and the etching time is 1 minute.
[0050] As shown in Table 1, the thickness before etching is... The thickness after etching under the above conditions is According to calculations, the etching rate is Furthermore, the etched surface is uniform and has no color difference.
[0051] Example 3
[0052] The preparation steps and detection methods for the electrochemical gold etching solution are the same as in Example 1.
[0053] Weigh 20 parts of 98% concentrated sulfuric acid and add it to 71.8 parts of pure water. Mix thoroughly and cool to room temperature. Then, weigh out 3 parts of potassium sulfate, 3 parts of a mixture of hexabromocyclododecane and 2 parts of isopropanol, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix thoroughly to form an electrochemical gold etching solution. The current density is 0.1 ASD, the stirring speed is 180 r / min, the etching temperature is 25℃, and the etching time is 1 minute.
[0054] As shown in Table 1, the thickness before etching is... The thickness after etching under the above conditions is According to calculations, the etching rate is Furthermore, the etched surface is uniform and has no color difference.
[0055] Example 4
[0056] The preparation steps and detection methods for the electrochemical gold etching solution are the same as in Example 1.
[0057] Weigh 20 parts of 98% concentrated sulfuric acid and add it to 71.8 parts of pure water. Mix thoroughly and cool to room temperature. Then, weigh out 3 parts of potassium sulfate, 3 parts of a mixture of hexabromocyclododecane and 2 parts of isopropanol, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix thoroughly to form an electrochemical gold etching solution. The current density is 0.1 ASD, the stirring speed is 180 r / min, the etching temperature is 25℃, and the etching time is 1 minute.
[0058] As shown in Table 1, the thickness before etching is... The thickness after etching under the above conditions is According to calculations, the etching rate is Furthermore, the etched surface is uniform and has no color difference.
[0059] Example 5
[0060] The preparation steps and detection methods for the electrochemical gold etching solution are the same as in Example 1.
[0061] Weigh 20 parts of 98% concentrated sulfuric acid and add it to 71.8 parts of pure water. Mix thoroughly and cool to room temperature. Then, weigh out 3 parts of potassium sulfate, 3 parts of a perfluorooctane sulfonyl compound + 2 parts of acetone mixture, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix thoroughly to form an electrochemical gold etching solution. The current density is 0.1 ASD, the stirring speed is 180 r / min, the etching temperature is 25℃, and the etching time is 1 minute.
[0062] As shown in Table 1, the thickness before etching is... The thickness after etching under the above conditions is According to calculations, the etching rate is Furthermore, the etched surface is uniform and has no color difference.
[0063] Example 6
[0064] The preparation steps and detection methods for the electrochemical gold etching solution are the same as in Example 1.
[0065] Weigh 20 parts of 98% concentrated sulfuric acid and add it to 69.8 parts of pure water. Mix thoroughly and cool to room temperature. Then, weigh out 5 parts of potassium sulfate, 3 parts of a mixture of hexabromocyclododecane and 2 parts of isopropanol, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix thoroughly to form an electrochemical gold etching solution. The current density is 0.1 ASD, the stirring speed is 180 r / min, the etching temperature is 25℃, and the etching time is 1 minute.
[0066] As shown in Table 1, the thickness before etching is... The thickness after etching under the above conditions is According to calculations, the etching rate is Furthermore, the etched surface is uniform and has no color difference.
[0067] Example 7
[0068] The preparation steps and detection methods for the electrochemical gold etching solution are the same as in Example 1.
[0069] Weigh 40 parts of 98% concentrated sulfuric acid and add it to 51.8 parts of pure water. Mix thoroughly and cool to room temperature. Then, weigh out 3 parts of potassium sulfate, 3 parts of a mixture of hexabromocyclododecane and 2 parts of acetone, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix thoroughly to form an electrochemical gold etching solution. The current density is 0.1 ASD, the stirring speed is 180 r / min, the etching temperature is 25℃, and the etching time is 1 minute.
[0070] As shown in Table 1, the thickness before etching is... The thickness after etching under the above conditions is According to calculations, the etching rate is Furthermore, the etched surface is uniform and has no color difference.
[0071] Example 8
[0072] The preparation steps and detection methods for the electrochemical gold etching solution are the same as in Example 1.
[0073] Weigh 40 parts of 98% concentrated sulfuric acid and add it to 51.8 parts of pure water. Mix thoroughly and cool to room temperature. Then, weigh out 5 parts of potassium sulfate, 3 parts of a mixture of hexabromocyclododecane and 2 parts of acetone, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix thoroughly to form an electrochemical gold etching solution. The current density is 1 ASD, the stirring speed is 180 r / min, the etching temperature is 25℃, and the etching time is 1 minute.
[0074] As shown in Table 1, the thickness before etching is... The thickness after etching under the above conditions is According to calculations, the etching rate is Furthermore, the etched surface is uniform and has no color difference.
[0075] Example 9
[0076] The preparation steps and detection methods for the electrochemical gold etching solution are the same as in Example 1.
[0077] Weigh 40 parts of 98% concentrated sulfuric acid and add it to 51.8 parts of pure water. Mix thoroughly and cool to room temperature. Then, weigh out 5 parts of potassium sulfate, 3 parts of a mixture of hexabromocyclododecane and 2 parts of acetone, 0.1 parts of dimethylammonium bromide, and 0.1 parts of GP and add them to the above solution. Mix thoroughly to form an electrochemical gold etching solution. The current density is 2 ASD, the stirring speed is 200 r / min, the etching temperature is 25℃, and the etching time is 1 minute.
[0078] As shown in Table 1, the thickness before etching is... The thickness after etching under the above conditions is According to calculations, the etching rate is Furthermore, the etched surface is uniform and has no color difference.
[0079] Table 1: Changes in wafer etching before and after comparative and example studies
[0080]
Claims
1. A semiconductor electrochemical gold etching solution, characterized in that: The electrochemical gold etching solution comprises 5-50% by mass of inorganic acid, 1-10% by mass of metal salt, 0.1-10% by mass of halide, 0.01%-1% by mass of surfactant, 0.1-5% by mass of detergent, and 0.01-1% by mass of defoamer, with the remainder being pure water. The inorganic acid is one or more of phosphoric acid, nitric acid, sulfuric acid, hydrochloric acid, and hydrofluoric acid. The metal salt is one or more of sodium / potassium phosphate, sodium / potassium nitrate, sodium / potassium sulfate, sodium / potassium chloride, and sodium / potassium fluoride. The anion of the added metal salt is the same as the anion of the inorganic acid. The halide is a polyhalogenated organic compound selected from one or more of hexabromocyclododecane, perfluorooctane sulfonyl compound, and pentachlorobenzoic acid.
2. The semiconductor electrochemical gold etching solution as described in claim 1, characterized in that: The total mass content of inorganic acid in the electrochemical gold etching solution is 10%-40%, and the pH value of the electrochemical gold etching solution is less than 1.
3. The semiconductor electrochemical gold etching solution as described in claim 1, characterized in that: The total mass content of metal salts in the electrochemical gold etching solution is 1%-5%.
4. The semiconductor electrochemical gold etching solution as described in claim 1, characterized in that: The surfactant is a cationic surfactant, selected from one or more of dodecylammonium chloride and dimethylammonium bromide.
5. The semiconductor electrochemical gold etching solution as described in claim 1, characterized in that: The detergent is one or more of ethanol, isopropanol, and acetone, and the polyhalogenated organic compound must first form a mixture with the detergent.
6. The semiconductor electrochemical gold etching solution as described in claim 1, characterized in that: The defoamer is one or more of the polyether-type defoamers GP, GPE, and GPES.
7. An etching method for a semiconductor electrochemical gold etching solution according to any one of claims 1-6, characterized in that: Electrochemical gold etching solution etches elemental gold on a semiconductor under the condition of current introduction. The semiconductor wafer is immersed in the electrochemical gold etching solution as the anode, and a cathode with the same area as the anode is immersed in the electrochemical gold etching solution. Current is simultaneously applied to the anode and cathode, and the electrochemical gold etching solution is in a disturbed state to etch elemental gold.
8. The etching method of the semiconductor electrochemical gold etching solution as described in claim 7, characterized in that: The anode and cathode need to be placed parallel to each other in the electrochemical gold etching solution. The distance between the anode and cathode is 2-5 cm. The current density on the anode is 0.1-5 ASD. The stirring rate of the electrochemical gold etching solution is 30-300 r / min. The working temperature of the electrochemical gold etching solution is 20-60℃.
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