Silicon wafer bearing device and method for reducing powder falling

Abstract

The invention discloses a silicon wafer bearing device and method for reducing powder falling, and the device comprises a light silicon wafer bearing device coated with a coating material, the light silicon wafer bearing device is made of a carbon / carbon composite material substrate, and provides bearing and heat transfer functions for a silicon wafer in a chemical vapor deposition and atomic layer deposition coating process. The coating material is a carbon coating material resistant to fluorine ion corrosion, and the coating material uniformly covers the surface of the light silicon wafer bearing device and is used for preventing the coating device from powder falling in the using process and avoiding pollution to the surface of the silicon wafer and the environment of the coating device. According to the invention, the carbon coating with a certain thickness is deposited on the surface of the carbon / carbon composite material-based carrier plate, and based on the performance compatibility of the carbon coating and the carbon / carbon composite material-based carrier plate, the carbon coating has the advantages of high corrosion resistance and high bonding strength, and can be used for many times in a high-temperature environment, and the coating material is not easy to crack and fall off.

Description

Technical Field

[0001] The invention belongs to the technical field of silicon wafer coating, and in particular relates to a silicon wafer carrying device and method for reducing powder loss. Background Art

[0002] In the photovoltaic and semiconductor processing flow, the coating process is a crucial link. The coating process plays a very critical role in photovoltaic and semiconductor manufacturing. It can improve the electrical conductivity, corrosion resistance and thermal conductivity of electronic components, and at the same time enhance the stability and reliability of components. The coating process is a commonly used surface treatment process. As one of the important steps in the manufacture of semiconductor devices, it generally needs to be carried out in an oxygen-free and dust-free vacuum environment. By depositing a certain metal or non-metal on the surface of the material in the form of a gas phase, a dense film is formed. The quality of the coating is crucial to the function of the semiconductor device.

[0003] The substrate that carries the silicon wafer also plays a key role in the coating process. During the coating process, the substrate needs to be in a gas atmosphere rich in fluoride ions for a long time. Metal materials are prone to react with fluoride ions, and carbon / carbon composite materials that are resistant to fluoride ion corrosion are prone to losing carbon powder, which in turn affects the cleanliness of the coating environment and has a great impact on the performance of semiconductor devices.

[0004] Therefore, developing silicon wafer carriers that are highly corrosion-resistant and do not drop carbon powder has become a key link in ensuring the excellent manufacturing of photovoltaic and semiconductor devices. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to solve the deficiencies in the prior art and to provide a silicon wafer carrying device and method for reducing powder loss.

[0006] Technical solution: A silicon wafer carrier device that reduces powder loss, including a lightweight silicon wafer carrier device covered with a coating material, wherein the lightweight silicon wafer carrier device is made of a carbon / carbon composite material substrate, and the lightweight silicon wafer carrier device provides a bearing and heat transfer function for the silicon wafer during the chemical vapor deposition and atomic layer deposition coating process, and the coating material is a carbon coating material resistant to fluorine ion corrosion, and the coating material is evenly covered on the surface of the lightweight silicon wafer carrier device, so as to prevent the coating device from losing powder during use, thereby avoiding pollution to the silicon wafer surface and the environment of the coating equipment.

[0007] A further improvement of the present invention is that the coating material is a pure carbon material and / or a non-metallic compound containing carbon elements.

[0008] A further improvement of the present invention is that the pure carbon material includes graphite, graphene, diamond-like carbon, and pyrolytic carbon, and the non-metallic chemical containing carbon elements includes silicon carbide.

[0009] A further improvement of the present invention is that the material of the lightweight silicon wafer carrier is selected from carbon / carbon composite materials, the types of carriers include short-fiber carbon fiber carriers and long-fiber carbon fiber carriers, and the thickness of the entire short-fiber carbon fiber carrier is 1 to 10 mm and the density is 1.2 to 1.5 g / cm 3 .

[0010] A further improvement of the present invention is that the thickness of the entire short-fiber carbon fiber carrier plate is 2 to 6 mm.

[0011] A further improvement of the present invention is that the thickness of the coating material is selected in the range of 1 to 30 μm, and the deposition time is selected in the range of 1 to 15 hours.

[0012] A further improvement of the present invention is that the thickness of the coating material ranges from 3 to 10 μm and the deposition time ranges from 2 to 5 hours.

[0013] A method for reducing powder loss of a silicon wafer carrier, according to a silicon wafer carrier for reducing powder loss, the method comprises the following steps: S1. Preparation of coating material, the preparation method of coating material includes magnetron sputtering and pyrolysis, the coating material on the lightweight silicon wafer carrier is a single-sided coating or a double-sided coating; S2. The lightweight silicon wafer carrier covered with a carbon coating is kept in a fluorine ion gas atmosphere for 24 hours, and the corrosion rate is less than 0.0001mm / a, the corrosion ratio is less than 0.02%, the color of the carbon / carbon composite material substrate before corrosion is black, and the color of the carbon / carbon composite material substrate after corrosion is black; S3. A lightweight silicon wafer carrier covered with a carbon coating material is subjected to a high temperature resistance test. The carbon coating material withstands a high temperature environment of 200 to 300°C to avoid cracking and falling off; S4. The bonding strength test of the lightweight silicon wafer carrier covered with carbon coating material is carried out, and the bonding strength level of the carbon coating material reaches level four or above.

[0014] Compared with the prior art, the present invention provides a silicon wafer supporting device and method for reducing powder loss, which achieves at least the following beneficial effects: The present invention covers a carbon coating material resistant to fluoride ion corrosion of a certain thickness on the surface of a carbon / carbon composite material substrate, and replaces conventional metal plates with carbon / carbon composite material substrate plates. The carbon coating has good compatibility with the carbon / carbon composite material substrate. The carbon coating has the advantages of high corrosion resistance and high bonding strength. A large bonding strength is formed between the carbon coating and the carbon / carbon composite material substrate, and the carbon coating can be used multiple times in a high temperature environment. The coating material is not prone to cracking and falling off, which ensures the service life of the carbon / carbon composite material substrate and greatly reduces the production cost of the device. The silicon wafer carrier device is widely used in the photovoltaic and semiconductor fields and in the CVD and ALD film deposition processes, which can greatly reduce the pollution to the silicon wafer surface and the environment of the coating equipment, improve the silicon wafer coating quality, and increase the production yield of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of a carbon / carbon composite substrate without a carbon coating; Figure 1 (a) is a short fiber carbon fiber carrier; Figure 1 (b) is a long fiber carbon fiber carrier; Figure 2 Schematic diagram of a short-fiber carbon fiber carrier plate covered with a PVD graphite carbon coating; Figure 3 (a) is a SEM image of the surface of the short-fiber carbon fiber substrate covered with PVD graphite carbon coating; Figure 3 (b) is a SEM image of the cross section of the short fiber carbon fiber substrate coated with PVD graphite carbon coating; Figure 4 This is a SEM image of the surface of the short-fiber carbon fiber substrate covered with PVD graphite carbon coating after fluoride ion gas cleaning; Figure 5 This is a SEM image of the cross section of a short-fiber carbon fiber substrate covered with a PVD graphite carbon coating after being treated in a high-temperature environment; Figure 6 This is the three-dimensional structure diagram of the short-fiber carbon fiber carrier; Figure 7 SEM image of the surface of the short-fiber carbon fiber substrate covered with pyrolytic carbon coating.

[0016] Description of reference numerals: 1-short fiber carbon fiber carrier; 2-long fiber carbon fiber carrier; 3-PVD graphite carbon coating; 4-short fiber carbon fiber carrier carrying a single silicon wafer; 5-short fiber carbon fiber carrier carrying multiple silicon wafers. DETAILED DESCRIPTION

[0017] Various exemplary embodiments of the present invention are now described in detail. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps, numerical expressions and numerical values ​​described in these embodiments do not limit the scope of the present invention. The following description of at least one exemplary embodiment is actually only illustrative and is not intended to be any limitation on the present invention and its application or use.

[0018] The techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered as part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0019] See also Figure 1-7 A silicon wafer carrier device and method for reducing powder loss, comprising a lightweight silicon wafer carrier device covered with a coating material, wherein the lightweight silicon wafer carrier device is made of a carbon / carbon composite material substrate, and the lightweight silicon wafer carrier device provides a bearing and heat transfer function for silicon wafers in the chemical vapor deposition and atomic layer deposition coating processes, wherein the coating material is a carbon coating material resistant to fluoride ion corrosion, and the coating material is evenly covered on the surface of the lightweight silicon wafer carrier device, so as to prevent the coating device from losing powder during use, thereby avoiding pollution to the silicon wafer surface and the environment of the coating equipment.

[0020] Carbon / carbon composite material is a carbon matrix composite material reinforced by carbon fiber and its fabric. Based on the inherent properties of carbon fiber, the corrosion of fluorine ions to carbon fiber is relatively weak. Therefore, in the CVD and ALD coating processes, carbon / carbon composite materials are ideal materials for preparing silicon wafer carriers. The present invention prepares two types of carbon / carbon composite substrates, see Figure 1 , one is short-fiber carbon fiber carrier, and the other is long-fiber carbon fiber carrier. The short-fiber carbon fiber carrier presents the characteristics of hard carbon fiber felt, while the long-fiber carbon fiber carrier presents the characteristics of three-dimensional carbon fiber cloth.

[0021] In the CVD and ALD coating systems, the metal silicon wafer carrier is extremely susceptible to fluorine ion corrosion, causing environmental pollution to the coating equipment. In order to ensure the cleanliness of the coating environment, carbon / carbon composite materials are used to prepare the silicon wafer carrier. However, the short-fiber carbon fiber carrier is prone to shed carbon powder on the surface after processing and forming. To address the carbon powder shedding phenomenon, magnetron sputtering and pyrolysis are used to cover the carrier surface with a certain thickness of carbon coating.

[0022] The subsequent embodiments all focus on the short-fiber carbon fiber carrier, and specifically test and study the corrosion resistance, high temperature resistance and bonding strength of the short-fiber carbon fiber carrier. The corrosion resistance, high temperature resistance and bonding strength of the long-fiber carbon fiber carrier are basically consistent with the performance of the short-fiber carbon fiber carrier. In addition, the performance of the short-fiber carbon fiber carrier covered with a single-sided coating or a double-sided coating is also basically consistent. The embodiments all focus on studying the short-fiber carbon fiber carrier covered with a double-sided coating.

[0023] Example 1 The selected size is 2030×2030mm 2 , thickness 2mm, density 1.2g / cm 3 , short-fiber carbon fiber carrier with a tensile strength of 0.1-0.52MPa. The whole short-fiber carbon fiber carrier contains 9×18 single silicon wafer carriers. The size of a single silicon wafer carrier is 210×105mm 2 A 3µm thick PVD graphite carbon coating was deposited on the substrate surface by magnetron sputtering for 2 h. Figure 2 . Figure 3 (a) is a SEM image of the surface of a short-fiber carbon fiber substrate coated with a 3µm thick PVD graphite carbon coating; Figure 3 (b) is the SEM image of the cross section of the short fiber carbon fiber substrate covered with a 3 µm thick PVD graphite carbon coating.

[0024] The element content analysis at different depths of the short fiber carbon fiber substrate cross section covered with 3 µm thick PVD graphite carbon coating is shown in the following table:

[0025] The results show that the surface of the short-fiber carbon fiber carrier is mainly composed of C elements, with a small amount of O and N elements, and the rest is 100% C elements from the outside to the inside.

[0026] Test 1: The short-fiber carbon fiber carrier plate covered with 3µm thick PVD graphite carbon coating was kept in NF3 gas atmosphere for 24 hours. By comparing the mass of the short-fiber carbon fiber carrier plate covered with PVD graphite carbon coating before and after corrosion, the corrosion rate was calculated to be 0.0001mm / a, and the corrosion ratio was about 0.015%. The color of the short-fiber carbon fiber carrier plate covered with PVD graphite carbon coating did not change significantly before and after corrosion. The color of the short-fiber carbon fiber carrier plate covered with PVD graphite carbon coating before corrosion was black, and the color of the short-fiber carbon fiber carrier plate covered with PVD graphite carbon coating after corrosion was black. Figure 4 This is an SEM image of the surface of a short-fiber carbon fiber substrate covered with a 3µm thick PVD graphite carbon coating after fluoride ion gas cleaning. The surface morphology of the PVD graphite carbon coating has not changed significantly.

[0027] Test 2: A high temperature resistance test was conducted on a short-fiber carbon fiber substrate covered with a 3µm thick PVD graphite carbon coating. The PVD graphite carbon coating was kept at a high temperature of 270°C for 1 hour without cracking or falling off. Figure 5 This is a SEM image of the cross section of a short-fiber carbon fiber substrate covered with a 3µm thick PVD graphite carbon coating after being treated in a high-temperature environment at 270°C. No obvious cracks or peeling PVD graphite carbon coating were found in the SEM image, indicating that the PVD graphite carbon coating has good high-temperature resistance.

[0028] Test three: The film bonding strength test was conducted on the short-fiber carbon fiber carrier covered with 3µm thick PVD graphite carbon coating. The short-fiber carbon fiber carrier covered with PVD graphite carbon coating was scratched in a cross grid shape with a hundred-grid knife. There was little base powder after the base was scratched. The scratch was pasted with tape. Compared with the unscratched tape, the blackening degree of the scratched tape reached 2.16%, and there was only a small amount of carbon coating material on the surface of the tape. It shows that the PVD graphite carbon coating deposited on the surface of the short-fiber carbon fiber carrier by magnetron sputtering has good bonding strength, and the bonding level reaches level four or above. The performance compatibility between the short-fiber carbon fiber carrier and the PVD graphite carbon coating is the fundamental guarantee to ensure that the PVD graphite carbon coating is not easy to fall off.

[0029] Example 2 The selected size is 2750×2750 mm 2 , thickness 4mm, density 1.3g / cm 3 , a short-fiber carbon fiber carrier with a tensile strength of 0.1 to 0.52 MPa. The entire short-fiber carbon fiber carrier contains 12×24 single silicon wafer carriers, and the size of a single silicon wafer carrier is 210×105 mm 2 ,See Figure 6 A 6µm thick PVD graphite carbon coating was deposited on the substrate surface by magnetron sputtering for 4h.

[0030] The element content of the short fiber carbon fiber substrate with 6µm thick PVD graphite carbon coating was analyzed at different depths, as shown in the following table:

[0031] The results show that the surface of the short-fiber carbon fiber carrier is mainly composed of C elements, with a small amount of O and N elements, and the rest is 100% C elements from the outside to the inside.

[0032] Test 1: The short-fiber carbon fiber carrier plate covered with 6µm thick PVD graphite carbon coating was kept in NF3 gas atmosphere for 24 hours. By comparing the mass of the short-fiber carbon fiber carrier plate covered with PVD graphite carbon coating before and after corrosion, the corrosion rate was calculated to be 0.0001mm / a, and the corrosion ratio was about 0.01%. The color of the short-fiber carbon fiber carrier plate covered with PVD graphite carbon coating did not change significantly before and after corrosion. The color of the short-fiber carbon fiber carrier plate covered with PVD graphite carbon coating before corrosion was black, and the color of the short-fiber carbon fiber carrier plate covered with PVD graphite carbon coating after corrosion was black.

[0033] Test 2: A high temperature resistance test was conducted on a short-fiber carbon fiber substrate coated with a 6µm thick PVD graphite carbon coating. The PVD graphite carbon coating can withstand a high temperature environment of 270°C for 1 to 2 hours without cracking or falling off. This shows that the PVD graphite carbon coating has good high temperature resistance.

[0034] Test three: The film bonding strength of the short-fiber carbon fiber carrier covered with a 6µm thick PVD graphite carbon coating was tested. The short-fiber carbon fiber carrier covered with the PVD graphite carbon coating was scratched in a cross grid shape with a hundred-grid knife. There was very little base powder after the base was scratched. The scratched area was pasted with tape. Compared with the unscratched tape, the blackening degree of the scratched tape reached 1.13%, and there was only a small amount of carbon coating material on the surface of the tape. It shows that the PVD graphite carbon coating deposited on the surface of the short-fiber carbon fiber carrier by magnetron sputtering has good bonding strength, and the bonding level reaches level four or above. The performance compatibility between the short-fiber carbon fiber carrier and the PVD graphite carbon coating is the fundamental guarantee to ensure that the PVD graphite carbon coating is not easy to fall off.

[0035] Example 3 The coating morphology, corrosion resistance, high temperature resistance and bonding strength of the short-fiber carbon fiber carrier coated with pyrolytic carbon coating were also tested and studied. Based on the performance compatibility of the carbon coating and the short-fiber carbon fiber carrier, the pyrolytic carbon coating exhibits similar properties to the PVD graphite carbon coating, which can effectively prevent the carbon powder from falling off the surface of the short-fiber carbon fiber carrier.

[0036] The selected size is 2750×2750 mm 2 , thickness is 6mm, density is 1.5g / cm 3 , a short-fiber carbon fiber carrier with a tensile strength of 0.1 to 0.52 MPa. The entire short-fiber carbon fiber carrier contains 12×24 single silicon wafer carriers, and the size of a single silicon wafer carrier is 210×105 mm 2 A 10µm thick pyrolytic carbon coating was deposited on the substrate surface by pyrolysis method for 5h. Figure 7 SEM image of the surface of a short-fiber carbon fiber substrate coated with a 10µm thick pyrolytic carbon coating.

[0037] The element content analysis of the short fiber carbon fiber substrate with 10µm thick pyrolytic carbon coating was carried out at different depths, as shown in the following table:

[0038] The results show that the surface of the short-fiber carbon fiber carrier is mainly composed of C elements, with a small amount of O and N elements, and the rest is 100% C elements from the outside to the inside.

[0039] Test 1: The short-fiber carbon fiber carrier plate covered with a 10µm thick pyrolytic carbon coating was kept in the NF3 gas atmosphere for 24 hours. By comparing the mass of the short-fiber carbon fiber carrier plate covered with the pyrolytic carbon coating before and after corrosion, the corrosion rate was calculated to be 0.00011mm / a, and the corrosion ratio was about 0.012%. The color of the short-fiber carbon fiber carrier plate covered with the pyrolytic carbon coating did not change significantly before and after corrosion. The color of the short-fiber carbon fiber carrier plate covered with the pyrolytic carbon coating before corrosion was black, and the color of the short-fiber carbon fiber carrier plate covered with the pyrolytic carbon coating after corrosion was black.

[0040] Test 2: A high temperature resistance test was conducted on a short-fiber carbon fiber substrate coated with a 10µm thick pyrolytic carbon coating. The pyrolytic carbon coating can withstand a high temperature environment of 270°C for 1 to 2 hours without cracking or falling off. This shows that the pyrolytic carbon coating has good high temperature resistance.

[0041] Test three: The film bonding strength of the short-fiber carbon fiber carrier covered with a 10µm thick pyrolytic carbon coating was tested. The short-fiber carbon fiber carrier covered with the pyrolytic carbon coating was scratched in a cross-grid shape with a hundred-grid knife. There was very little base powder after the base was scratched. The scratched area was pasted with tape. Compared with the unscratched tape, the blackening degree of the scratched tape reached 1.45%, and there was only a small amount of carbon coating material on the surface of the tape. It shows that the pyrolytic carbon coating deposited on the surface of the short-fiber carbon fiber carrier by pyrolysis has good bonding strength, and the bonding level reaches level four or above. The performance compatibility between the short-fiber carbon fiber carrier and the pyrolytic carbon coating is the fundamental guarantee to ensure that the pyrolytic carbon coating is not easy to fall off.

[0042] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A silicon wafer carrying device for reducing powder loss, characterized in that: It includes a lightweight silicon wafer supporting device covered with a coating material, the lightweight silicon wafer supporting device is made of a carbon / carbon composite material substrate, the lightweight silicon wafer supporting device provides supporting and heat transfer functions for the silicon wafer during the chemical vapor deposition and atomic layer deposition coating process, the coating material is a carbon coating material resistant to fluorine ion corrosion, the coating material is evenly covered on the surface of the lightweight silicon wafer supporting device, and is used to prevent the coating device from shedding powder during use, thereby avoiding pollution to the silicon wafer surface and the environment of the coating equipment.

2. A silicon wafer carrying device for reducing powder loss according to claim 1, characterized in that: The coating material is a pure carbon material and / or a non-metallic compound containing carbon elements.

3. A silicon wafer carrying device for reducing powder loss according to claim 2, characterized in that: The pure carbon material includes graphite, graphene, diamond-like carbon, and pyrolytic carbon, and the non-metallic chemical containing carbon elements includes silicon carbide.

4. The silicon wafer carrying device for reducing powder loss according to claim 1, characterized in that: The material of the lightweight silicon wafer carrier is a carbon / carbon composite material. The types of carriers include short-fiber carbon fiber carriers and long-fiber carbon fiber carriers. The thickness of the entire short-fiber carbon fiber carrier is 1 to 10 mm and the density is 1.2 to 1.5 g / cm 3 .

5. The silicon wafer carrying device for reducing powder loss according to claim 4, characterized in that: The thickness of the entire short-fiber carbon fiber carrier plate is 2 to 6 mm.

6. The silicon wafer carrying device for reducing powder loss according to claim 1, characterized in that: The thickness of the coating material is selected in the range of 1 to 30 μm, and the deposition time is selected in the range of 1 to 15 hours.

7. A silicon wafer carrying device for reducing powder loss according to claim 6, characterized in that: The thickness of the coating material ranges from 3 to 10 μm, and the deposition time ranges from 2 to 5 hours.

8. A method for reducing powder loss from a silicon wafer carrier, according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1. Preparation of coating material, the preparation method of coating material includes magnetron sputtering and pyrolysis, the coating material on the lightweight silicon wafer carrier is a single-sided coating or a double-sided coating; S2. The lightweight silicon wafer carrier covered with a carbon coating is kept in a fluorine ion gas atmosphere for 24 hours, and the corrosion rate is less than 0.0001mm / a, the corrosion ratio is less than 0.02%, the color of the carbon / carbon composite material substrate before corrosion is black, and the color of the carbon / carbon composite material substrate after corrosion is black; S3. A lightweight silicon wafer carrier covered with a carbon coating material is subjected to a high temperature resistance test. The carbon coating material withstands a high temperature environment of 200 to 300°C to avoid cracking and falling off; S4. The bonding strength test of the lightweight silicon wafer carrier covered with carbon coating material is carried out, and the bonding strength level of the carbon coating material reaches level four or above.

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