A surface treatment method for enhancing the adhesion of a gold coating to a quartz surface

Abstract

The application provides a surface treatment method for enhancing the adhesion of a gold coating on a quartz surface, comprising the following steps: (1) depositing catalytic metal particles on a clean quartz wafer; (2) removing the oxide layer on the surface of the catalytic metal particles on the quartz wafer obtained in step (1); (3) growing silicon nanostructures on the surface of the quartz wafer obtained in step (2) using silane gas; (4) high-temperature oxidation of the quartz wafer obtained in step (3) to change the silicon nanostructures into silicon oxide; (5) coating the quartz wafer obtained in step (4) with organic gold paste; and (6) heat treatment of the quartz wafer obtained in step (5) to decompose the organic gold on the surface and form a gold coating. The method can effectively control the morphology of the nanostructures, and the grown nanostructures can form a large number of mechanical bite action points, thereby forming a mechanical interlocking structure with the gold coating and effectively enhancing the adhesion of the gold coating on the quartz surface.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of surface engineering, and particularly relates to a surface treatment method for enhancing the adhesion of a gold coating on a quartz surface. BACKGROUND

[0002] Semiconductor epitaxy process is a key step for manufacturing high-performance devices and chips, which is usually carried out in a quartz epitaxy reactor. Since high-purity quartz has good light transmittance in the near-infrared region, most of the heat generated by the heating susceptor will be dissipated in the form of thermal radiation to the outside of the reaction chamber if there is no appropriate reflective coating. In addition, the greater the temperature difference between the upper and lower surfaces of the epitaxial wafer, the more serious the wafer warping, which causes crystal slip in the epitaxial layer and results in crystal defects, leading to a decrease in device yield. Therefore, a gold coating with a certain thickness is usually coated on the surface of the quartz epitaxy reactor to reflect the infrared radiation generated by the susceptor back into the reaction chamber, thereby reducing energy loss, reducing the temperature difference between the upper and lower surfaces of the wafer, and improving the quality of the epitaxial layer.

[0003] In the silicon epitaxy process, the temperature of the side wall of the reaction chamber is 300-600℃. Due to the large difference in the thermal expansion coefficient between gold and quartz, the adhesion of gold on the quartz surface is poor, which leads to the easy peeling of the gold coating on the quartz surface, greatly increasing the operating cost of the equipment.

[0004] Generally, the adhesion of the coating is enhanced by increasing the roughness of the quartz surface to increase the contact area or form a mechanical interlocking effect. Sandblasting treatment is a commonly used surface treatment technology, but it will cause great damage to the quartz substrate and has insufficient control over the surface structure; chemical etching methods can also enhance the surface roughness, but they involve strong acids and strong bases, which are highly polluting and have poor controllability of the surface structure.

[0005] Patent application No. CN104176943A discloses a method for increasing the etched roughness of a quartz wafer surface, which first evaporates a metal mask layer on the surface of the quartz wafer, and then uses a reactive ion etching machine to etch the surface of the quartz wafer to obtain a quartz wafer with a rough surface, thereby increasing the etched roughness of the quartz wafer surface.

[0006] The commonly used surface structure treatment methods are mostly top-down techniques, which have weak structure control ability and only increase the roughness of the substrate, making it difficult to obtain a structure that can form a mechanical interlocking effect. For coatings that are difficult to form strong bonds, such as quartz and gold coatings, the adhesion enhancement effect is limited.

[0007] Patent application EP 0 237 206 A2 discloses a process for forming a highly reflective gold coating on quartz. The application vapor deposits a thin gold-chromium coating on quartz, then vapor deposits a pure gold layer, then coats a polymer protective layer, and then heats to form an interface oxide of chromium to enhance the adhesion of the gold-chromium layer to the quartz and to cure the polymer. The gold-chromium coating of the application has excellent adhesion between the quartz and the gold coating structure, and the polymer protects the gold coating from mechanical wear and erosion (such as water and heat), but there is still room for improvement in enhancing the adhesion of the gold coating to the quartz surface. SUMMARY

[0008] To solve the above problems in the prior art, the present application provides a surface treatment method for enhancing the adhesion of a gold coating to a quartz surface, comprising the following steps:

[0009] (1) depositing catalytic metal particles on a cleaned quartz wafer;

[0010] (2) removing the oxide layer on the surface of the catalytic metal particles on the quartz wafer obtained in step (1);

[0011] (3) growing silicon nanostructures on the surface of the quartz wafer obtained in step (2) using silane gas;

[0012] (4) high-temperature oxidation of the quartz wafer obtained in step (3) to convert the silicon nanostructures into silicon oxide;

[0013] (5) coating the surface of the quartz wafer obtained in step (4) with organic gold paste;

[0014] (6) heat treating the quartz wafer obtained in step (5) to decompose the organic gold on the surface and form a gold coating.

[0015] Preferably, the catalytic metal in step (1) is one or more of tin, indium, gallium, and gold.

[0016] Preferably, the catalytic metal in step (1) is deposited on the quartz wafer by thermal evaporation.

[0017] Preferably, the catalytic metal film in step (1) has a thickness of 3-5 nm, and further preferably 3 nm. The thickness of the catalytic metal film is controlled by the plating process parameters. The thickness of the catalytic metal film affects the particle diameter of the catalytic metal, which in turn affects the diameter and height of the silicon nanostructures.

[0018] Preferably, steps (2) and (3) are carried out in a plasma-enhanced chemical vapor deposition system.

[0019] Preferably, the process conditions in step (2) are: temperature of 150-250℃, further preferably 200℃; hydrogen flow rate of 15-25 SCCM, further preferably 20 SCCM; radio frequency power of 5-15 mW / cm 2 , further preferably 10 mW / cm 2 ; chamber pressure of 20-50 Pa, further preferably 30 Pa; hydrogen plasma treatment time of 5-10 min, further preferably 5 min. Changes in the process parameters affect the size of the silicon nanostructures produced.

[0020] Preferably, the process conditions in step (3) are: hydrogen flow rate of 50-70 SCCM, further preferably 60 SCCM; silane flow rate of 5-10 SCCM, further preferably 6 SCCM; chamber temperature of 300-400℃, further preferably 350℃; radio frequency power density of 15-35 mW / cm 2 , further preferably 20 mW / cm 2 ; chamber pressure of 80-120 Pa, preferably 100 Pa; nanostructure growth time of 5-10 min, preferably 5 min. Changes in the process parameters here also affect the size of the silicon nanostructures produced. By controlling the hydrogen flow rate, the reaction rate can be controlled and the quality of the nanostructures improved.

[0021] Preferably, the silane gas in step (3) is monosilane (SiH4) gas.

[0022] Preferably, in step (4), the sample is transferred to a muffle furnace, the temperature is set to 900-1000℃, further preferably 900℃; annealing in air for 50-100 min, further preferably 60 min; the silicon nanostructures are oxidized. The temperature affects the oxidation time of the nanostructures, the lower the temperature, the longer the oxidation time required.

[0023] Preferably, in step (5), the organic gold paste comprises resin acid gold, metal additives, resin and solvent, and the organic gold paste is coated on the surface of the treated sample by brushing or spraying.

[0024] Preferably, in step (6), the method of heat treatment is high-temperature annealing or infrared heating.

[0025] Preferably, in step (6), the method of heat treatment is high-temperature annealing, the high-temperature annealing temperature is 750-850℃, further preferably 800℃; the high-temperature annealing time is 10-15 min, further preferably 15 min; the heating rate is 10℃ / min.

[0026] The present application has the following beneficial effects:

[0027] This invention provides a surface treatment method to enhance the adhesion of a gold coating on a quartz surface. It employs a bottom-up nanostructure growth technique, which can effectively control the morphology of the nanostructure. Without affecting the optical properties of the coating, a large number of mechanical interlocking points are formed on the silicon nanostructure, enabling the silicon nanostructure grown on the quartz surface to form numerous mechanically interlocked structures with the gold coating, effectively enhancing the adhesion of the gold coating to the quartz surface. Attached Figure Description

[0028] Figure 1 The images show a plan view and a side view of the nanostructure on the quartz surface in Embodiment 1 of the present invention.

[0029] Figure 2 The image shows the microstructure of the gold coating on the quartz surface in Example 1 and Comparative Example 1.

[0030] Figure 3 The graph shows the results of the adhesion strength test of the gold coating in Example 1 and Comparative Example 1. Detailed Implementation

[0031] Example 1

[0032] The preparation process of quartz surface nanostructures is as follows:

[0033] First, a 3 nm layer of catalytic tin was deposited on the surface of quartz using a thermal evaporation deposition apparatus.

[0034] The quartz sample with catalytic tin deposited on its surface was then transferred to a plasma-enhanced chemical vapor deposition (PECVD) system. Nanostructures were fabricated using the VLS nanowire growth mode. The specific process includes:

[0035] At a temperature of 200℃, the hydrogen flow rate is 20 SCCM, and the radio frequency power is 10 mW / cm. 2 The chamber pressure is 30 Pa. Hydrogen plasma is used to treat the tin particles for about 5 minutes to reduce the oxide layer on the surface of the tin particles and form catalytic metal particles.

[0036] Then hydrogen and silane (SiH4) are introduced, with a hydrogen flow rate of 60 SCCM and a silane flow rate of 6 SCCM. The chamber temperature is 350℃, and the radio frequency power density is 20 mW / cm². 2 The chamber pressure was 100 Pa, and the nanostructure growth time was 5 min.

[0037] The quartz sample with silicon nanostructures on the surface is transferred into a muffle furnace, the temperature is set to 900°C, and the silicon nanostructures are oxidized by annealing in air for 60 min. After the quartz sample is cooled to room temperature, it is taken out and a layer of organic gold paint is brushed on the surface of the quartz sample using a brush. The main component of the organic gold paint is resin acid gold, the solid content is 40wt%, and the solvent is pine oil + pine oil alcohol (volume ratio of 1:1). The quartz sample brushed with organic gold paint is placed for 20 min, and then transferred into a muffle furnace for annealing, the heating rate is 10°C / min, heated to 800°C, and kept for 15 min. When the temperature of the quartz sample is below 100°C, it is taken out, and a gold coating is coated on the surface of the quartz sample.

[0038] Example 2

[0039] The preparation process of the quartz surface nanostructure is as follows:

[0040] First, a 3nm catalytic metal tin is deposited on the surface of the quartz using a thermal evaporation deposition device.

[0041] Then the quartz sample with catalytic metal tin deposited on the surface is transferred into a plasma enhanced chemical vapor deposition system (PECVD), and nanostructures are prepared using the VLS nanowire growth mode, the specific process including:

[0042] At a temperature of 150°C, the hydrogen flow is 15 SCCM, the radio frequency power is 5mW / cm 2 , the chamber pressure is 20Pa, and the surface oxide layer of the tin particles is reduced by hydrogen plasma treatment for about 5min to form catalytic metal particles;

[0043] Then hydrogen and silane (SiH4) are introduced, the hydrogen flow is 50 SCCM, the silane flow is 5 SCCM, the chamber temperature is 300°C, the radio frequency power density is 15mW / cm 2 , the chamber pressure is 80Pa, and the nanostructure growth time is 5min.

[0044] The quartz sample with silicon nanostructures on the surface is transferred into a muffle furnace, the temperature is set to 900°C, and the silicon nanostructures are oxidized by annealing in air for 60 min. After the quartz sample is cooled to room temperature, it is taken out and a layer of organic gold paint is brushed on the surface of the quartz sample using a brush. The main component of the organic gold paint is resin acid gold, the solid content is 40wt%, and the solvent is pine oil + pine oil alcohol (volume ratio of 1:1). The quartz sample brushed with organic gold paint is placed for 20 min, and then transferred into a muffle furnace for annealing, the heating rate is 10°C / min, heated to 800°C, and kept for 15 min. When the temperature of the quartz sample is below 100°C, it is taken out, and a gold coating is coated on the surface of the quartz sample.

[0045] Example 3

[0046] The process for preparing the nanostructure on the surface of quartz is as follows:

[0047] First, a 5nm catalytic metal tin is deposited on the surface of quartz by using a thermal evaporation deposition device.

[0048] Then, the quartz sample with the catalytic metal tin deposited on the surface is transferred into a plasma enhanced chemical vapor deposition system (PECVD) to prepare the nanostructure by using the VLS nanowire growth mode, and the specific process includes:

[0049] At a temperature of 250°C, a hydrogen flow rate of 25 SCCM, a radio frequency power of 15 mW / cm 2 , a chamber pressure of 50 Pa, and a hydrogen plasma treatment for about 10 min, the surface oxide layer of the tin particles is reduced to form catalytic metal particles;

[0050] Then, hydrogen and monosilane (SiH4) are introduced, wherein the hydrogen flow rate is 70 SCCM, the monosilane flow rate is 10 SCCM, the chamber temperature is 400°C, the radio frequency power density is 35 mW / cm 2 , the chamber pressure is 120 Pa, and the nanostructure growth time is 10 min.

[0051] The quartz sample with the silicon nanostructure grown on the surface is transferred into a muffle furnace, the temperature is set to 1000°C, and the silicon nanostructure is annealed in air for 100 min. After the quartz sample is cooled to room temperature, it is taken out and a layer of organic gold paint is brushed on the surface of the quartz sample by using a brush. The main component of the organic gold paint is resin acid gold, the solid content is 40wt%, and the solvent is pine oil + pine oil alcohol (volume ratio of 1:1). The quartz sample brushed with the organic gold paint is left to stand for 30 min, and then it is transferred into a muffle furnace for annealing, the heating rate is 10°C / min, the temperature is raised to 850°C, and it is kept for 15 min. After the temperature of the quartz sample is reduced to below 100°C, it is taken out, and a gold coating is coated on the surface of the quartz sample.

[0052] Comparative Example 1

[0053] A layer of organic gold paint is brushed on the surface of the quartz sample by using a brush, and the main component of the organic gold paint is resin acid gold, the solid content is 40wt%, and the solvent is pine oil + pine oil alcohol (volume ratio of 1:1). The quartz sample brushed with the organic gold paint is left to stand for 20 min, and then it is transferred into a muffle furnace for annealing, the heating rate is 10°C / min, the temperature is raised to 800°C, and it is kept for 15 min. After the temperature of the quartz sample is reduced to below 100°C, it is taken out, and a gold coating is coated on the surface of the quartz sample.

[0054] Detection Example 1

[0055] The nanostructures prepared in Example 1 were characterized using scanning electron microscopy (SEM). The results are as follows: Figure 1 As shown, the results indicate that the nanostructures are uniformly distributed on the surface of the quartz substrate, and most of the nanostructures have a larger top size than the bottom size, which can form a good mechanical interlock with the gold coating, thereby improving the adhesion of the gold coating on the quartz surface.

[0056] Detection Example 2

[0057] The gold coating structures prepared in Example 1 and Comparative Example 1 were characterized using scanning electron microscopy (SEM), and the results are as follows: Figure 2 As shown, the results indicate that the nanostructure on the quartz substrate can effectively improve the microstructure of the gold coating, reduce pore defects in the gold coating, make the gold coating more compact, and thus improve the service life of the gold coating.

[0058] Detection Example 3

[0059] The adhesion strength of the gold coating on the quartz surface in Example 1 and Comparative Example 1 was measured using a scratch instrument. The adhesion strength of the coating refers to the magnitude of the bonding force between the coating and the substrate, that is, the energy required for a unit surface area of ​​the coating to peel off from the substrate (or intermediate coating).

[0060] The results are as follows Figure 3 As shown, when the load reaches 27 mN (milline Newtons), the gold coating on the quartz surface without grown nanostructures detaches, specifically manifested as a change in the coefficient of friction. Combined with the test data, it can be concluded that the adhesion strength of the gold coating on a smooth quartz surface without grown nanostructures is 20 J / m. 2 The gold coating on the quartz surface with the grown nanostructure did not detach within the equipment's testing range (load of 0-80 mN), specifically, the coefficient of friction remained unchanged, i.e., the friction force f - load F N The slope of the relationship curve did not change, indicating that after the nanostructure was grown on the quartz surface, a strong bonding force was formed between the gold coating on the quartz surface and the quartz substrate, resulting in a large adhesion strength.

Claims

1. A surface treatment method for enhancing the adhesion of a gold coating on a quartz surface, characterized in that, Includes the following steps: (1) Deposit catalytic metal particles on a cleaned quartz plate; (2) Remove the oxide layer on the surface of the catalytic metal particles on the quartz plate obtained in step (1); (3) Using silane gas, silicon nanostructures are grown on the surface of the quartz sheet obtained in step (2); (4) The quartz sheet obtained in step (3) is oxidized at high temperature to turn the silicon nanostructure into silicon oxide; (5) Coat the surface of the quartz sheet obtained in step (4) with organic gold paste; (6) Heat-treat the quartz sheet obtained in step (5) to decompose the organic gold on the surface and form a gold coating. The process conditions in step (2) are: temperature 150-250 ℃, hydrogen flow rate 15-25 SCCM, and radio frequency power 5-15 mW / cm. 2 The chamber pressure is 20-50 Pa, and the hydrogen plasma treatment time is 5-10 min. The process conditions in step (3) are as follows: hydrogen flow rate of 50-70 SCCM, silane flow rate of 5-10 SCCM, chamber temperature of 300-400 ℃, and RF power density of 15-35 mW / cm². 2 The chamber pressure is 80-120 Pa, and the nanostructure growth time is 5-10 min; In step (4), the high-temperature oxidation temperature is 900-1000 ℃ and the time is 50-100 min; The heat treatment method described in step (6) is high-temperature annealing, with a high-temperature annealing temperature of 750-850 ℃, a high-temperature annealing time of 10-15 min, and a heating rate of 10 ℃ / min.

2. The surface treatment method for enhancing the adhesion of gold coating on quartz surfaces according to claim 1, characterized in that, The catalytic metal mentioned in step (1) is one or more of tin, indium, gallium and gold.

3. The surface treatment method for enhancing the adhesion of gold coating on quartz surfaces according to claim 1, characterized in that, The catalytic metal described in step (1) is deposited on the quartz plate by thermal evaporation.

4. The surface treatment method for enhancing the adhesion of gold coating on quartz surfaces according to claim 1, characterized in that, The thickness of the catalytic metal film in step (1) is 3-5 nm.

5. The surface treatment method for enhancing the adhesion of gold coating on quartz surfaces according to claim 1, characterized in that, Steps (2) and (3) are performed in a plasma-enhanced chemical vapor deposition system.

6. The surface treatment method for enhancing the adhesion of gold coating on quartz surface according to claim 1, characterized in that, The organic gold paste in step (5) includes resin gold, metal additives, resin and solvent, and the organic gold paste is coated on the surface of the treated sample by brushing or spraying.

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