Method for prolonging service life of quartz bell jar of PVD (Physical Vapor Deposition) equipment

Abstract

The invention discloses a method for prolonging the on-machine service life of a quartz clock cover of PVD (Physical Vapor Deposition) equipment. The method comprises the following steps: S1, cleaning the quartz clock cover for the first time; s2, the quartz clock cover is subjected to sand blasting treatment; s3, cleaning the quartz clock cover for the second time; s4, the quartz clock cover is subjected to spraying treatment, and a coating is formed on the surface of the quartz clock cover; wherein in the step S4, Y2O3 powder is used for spraying the quartz clock cover. According to the method for prolonging the on-machine service life of the quartz clock cover of the PVD equipment, the coating is formed on the surface of the quartz clock cover, so that the adsorption force of attachments on the surface of the quartz clock cover is better, quartz chippings cannot fall off, the service life of a PVD machine table can be prolonged, and the wafer yield is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors, and in particular relates to a method for extending the service life of a quartz bell jar of a PVD device. Background Art

[0002] Semiconductor integrated circuit manufacturing technology continues to develop rapidly, and its process is accelerating towards miniaturization, high density and high integration. The PVD (physical sputtering) process in semiconductor manufacturing equipment is an indispensable part of the chip manufacturing process. During the production process of the PVD machine, a layer of Si-containing byproducts is gradually deposited on the surface of the DOME (quartz bell jar). These pollutants will fall off during operation; or the low surface roughness of the DOME (quartz bell jar) will cause insufficient subsequent adhesion and a short machine time; in addition, the quartz itself will also be corroded by some special processes, forming particles in the cavity, causing defects in wafer processing, reducing the yield of the wafer, and restricting the processing cost of the wafer. Therefore, the surface state and cleanliness of semiconductor parts become very important.

[0003] The DOME (bell jar) made of quartz has extremely low thermal expansion coefficient, high temperature resistance, excellent chemical stability, excellent electrical insulation, low and stable ultrasonic delay performance, the best ultraviolet spectrum performance, visible light and near infrared spectrum performance, and has higher mechanical properties than ordinary glass. It has high dielectric strength and extremely low conductivity, that is, it can still maintain high dielectric strength and resistance under high temperature, high pressure and high frequency, and there is almost no dielectric loss in the applied frequency band, so quartz is an excellent high-temperature dielectric insulation material.

[0004] At present, nitric and fluoric acid soaking is used to remove metal ions and surface foreign matter, and white corundum sandblasting is used to roughen the Dome (quartz bell), and then high-pressure water, ultrasonic waves, and baking are used. On the one hand, sandblasting is used to remove the film and thicken the surface during the cleaning process. Sandblasting will cause some embedded debris in the quartz, which cannot be completely removed by cleaning. On the other hand, sandblasting will also cause the quartz to produce sharp tips, which will also fall off in the process gas or environment of the machine. This process can meet the basic needs of 8-inch processes or low-end processes, but in the production process of 12-inch wafers, there is a most critical particle problem that often occurs. Sandblasting causes the Dome (quartz bell) surface roughness range to be relatively large, and the uniformity is not good. The adsorption effect is not good in places with low roughness, and particles will also be generated, which directly affects the stability of the machine, greatly shortens the service life of the machine, and increases the cost of PM (machine maintenance), thereby reducing the yield of wafer processing and increasing the cost of wafers.

[0005] It is hoped to provide an improved method for extending the service life of a quartz bell jar of a PVD device, particularly regarding how to increase the service life of a PVD machine and improve the wafer yield. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a method for extending the service life of a quartz bell jar of a PVD device, the purpose of which is to increase the service life of the PVD machine.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a method for extending the service life of a quartz bell jar of a PVD device, comprising the steps of:

[0008] S1, cleaning the quartz bell jar for the first time;

[0009] S2, sandblasting the quartz bell jar;

[0010] S3, cleaning the quartz bell jar for the second time;

[0011] S4, spraying the quartz bell jar to form a coating on the surface of the quartz bell jar;

[0012] Wherein, in step S4, Y2O3 powder is used to spray the quartz bell jar.

[0013] In step S4, the spraying thickness is 150-200 um.

[0014] In step S4, the spraying gas pressure is 2.0-3.0 MPa.

[0015] In the step S2, white corundum is used as the sandblasting material, and the mesh number of the sand material is 24#.

[0016] In step S2, the sandblasting gas pressure is 0.3-0.4 MPa.

[0017] In the step S2, when the quartz bell jar is sandblasted, the incident angle formed by the blasting direction and the surface of the quartz bell jar is 45° to 90°.

[0018] In step S2, the distance between the nozzle of the sandblasting equipment and the surface of the quartz bell jar is 15 cm.

[0019] In step S4, the distance between the nozzle of the spraying equipment and the surface of the quartz bell jar is 15 cm.

[0020] In the step S4, a protective jig is used to shield the sealing surface of the quartz bell jar, and the protective jig is made of stainless steel.

[0021] In the step S2, a protective jig is used to shield the sealing surface of the quartz bell jar.

[0022] The method for extending the service life of a quartz bell jar of a PVD device of the present invention forms a coating on the surface of the quartz bell jar, so that the adsorption force of the attached objects on the surface of the quartz bell jar is better, and the quartz debris cannot fall off, which can increase the service life of the PVD machine and improve the wafer yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] This specification includes the following drawings, which show the following contents:

[0024] Figure 1 It is a flow chart of a method for extending the service life of a quartz bell jar of a PVD device of the present invention;

[0025] Figure 2 This is an enlarged view of the quartz bell and the spraying boundary of the quartz bell;

[0026] Figure 3 It is a schematic diagram of the protection fixture structure;

[0027] Figure 4 It is a schematic diagram of the protection fixture and quartz bell structure;

[0028] Marked in the figure: 1. Protection boundary; 2. Quartz bell jar; 3. Protection fixture. DETAILED DESCRIPTION

[0029] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0030] like Figure 1 As shown, the present invention provides a method for extending the service life of a quartz bell jar of a PVD device, comprising the following steps:

[0031] S1, cleaning the quartz bell jar for the first time;

[0032] S2. Sandblasting the quartz bell jar to increase the surface roughness of the quartz bell jar;

[0033] S3, cleaning the quartz bell jar for the second time;

[0034] S4. The quartz bell jar is sprayed to form a coating on the surface of the quartz bell jar.

[0035] Specifically, the conventional practice for shielding and protecting quartz parts is to use sandblasting tape to protect the parts that do not need sandblasting. For some irregularly shaped parts, it is inconvenient for employees to apply tape. The tape is easily broken by the sand material during sandblasting, causing part contamination, and when the tape is removed, it is easy to leave residual offset marks on the surface of the part.

[0036] The present invention completely changes the traditional sandblasting tape shielding protection method, uses a contoured jig to directly fill the part that needs to be protected, and avoids the problems of residual glue and offset printing.

[0037] In the present invention, the method for manufacturing a quartz bell jar of a semiconductor PVD device adopts white corundum as a sandblasting material, and performs sandblasting by a certain gas pressure, and then uses Y2O3 powder to spray the semiconductor Dome (quartz bell jar) to optimize its surface roughness and make its use property more stable. The Y2O3 powder separates the quartz from the reaction chamber, so that the adsorption force of the surface attachments is better and the quartz debris cannot fall off.

[0038] The above step S1 comprises:

[0039] S101. Use acid and alkali resistant tape to cover the sealing surface of the quartz bell jar;

[0040] S102, mixed acid immersion etching adsorption film;

[0041] S103, quartz bell jar immersed in pure water;

[0042] S104, using ultrasonic equipment to clean the quartz bell jar;

[0043] S105, drying the quartz bell jar.

[0044] In the above step S102, the quartz bell jar is soaked in nitric and hydrofluoric acid and then cleaned to remove dirt and metal ions on the surface of the quartz bell jar.

[0045] In the above step S2, a protective jig is also used to shield the cleaned quartz bell jar, and the protective jig directly covers the sealing surface of the quartz bell jar that needs to be protected, exposing the part of the quartz bell jar that needs to be sandblasted, that is, the working surface of the quartz bell jar, such as Figure 2 As shown, the working surface is an inner concave surface (when in use, the quartz bell is turned upside down on the silicon wafer, the silicon wafer is under the quartz bell, the chamber formed by the inner concave surface is a vacuum special gas chamber, and the deposited film is mostly SIO2), and the sealing surface is located at the outer edge of the working surface. The protective fixture is made of stainless steel and can be repeatedly regenerated and cleaned, which prolongs the service life of the protective fixture and reduces the cost of protecting and shielding product components. The shape of the protective fixture matches the shape of the quartz bell. Using a contoured fixture for protection requires low employee skills and is suitable for mass production.

[0046] In the above step S2, white corundum is used as the sandblasting material, the mesh number of the sand material is 24#, and the sandblasting gas pressure is 0.3-0.4 MPa. Exemplarily, the sandblasting gas pressure can be 0.31 MPa, 0.33 MPa, 0.36 MPa, 0.38 MPa or 0.39 MPa.

[0047] In the above step S2, the incident angle formed by the spray direction and the surface of the quartz bell jar during sandblasting of the quartz bell jar is 45° to 90°. During the sandblasting process, the distance between the nozzle of the sandblasting equipment and the surface of the quartz bell jar is 15 cm. Sandblasting is destructive to the quartz base material and is irreversible; this parameter enables the sandblasting process to ensure the surface roughness that needs to be processed, while minimizing the loss of the sand material to the quartz itself, increasing the number of uses of the quartz and saving the cost of purchasing consumables.

[0048] The above step S3 includes:

[0049] S301. Use acid and alkali resistant tape to cover the sealing surface of the quartz bell jar;

[0050] S302, mixed acid immersion etching adsorption film;

[0051] S303, quartz bell jar immersed in pure water;

[0052] S304, using ultrasonic equipment to clean the quartz bell jar;

[0053] S305, drying the quartz bell jar.

[0054] In the above step S302, the quartz bell is soaked in nitric and hydrofluoric acid and then cleaned to remove the embedded debris on the quartz surface after sandblasting.

[0055] In the above step S4, a protective jig is used to shield the sealing surface of the quartz bell jar. The protective jig directly covers the part of the quartz bell jar surface that needs to be protected, namely the sealing surface, and exposes the part of the quartz bell jar surface that needs to be sprayed, namely the working surface of the quartz bell jar.

[0056] The same protective jig can be used for both the sandblasting process and the Y2O3 spraying process to protect the sealing surface of the quartz bell jar, which is versatile and convenient. Through the combination of the jig and the sealing surface, the surface cover can be protected from damage during both the sandblasting and spraying processes, which is also better than the traditional tape protection method.

[0057] In the above step S4, the quartz bell is sprayed with Y2O3 (yttrium oxide) powder, and the spraying thickness is 150-200um. Exemplarily, the spraying thickness can be 160um, 170um, 180um, 190um or 195um. The spraying gas pressure is 2.0-3.0Mpa. Exemplarily, the spraying gas pressure can be 2.1MPa, 2.3MPa, 3.5MPa, 2.8MPa or 2.9MPa. Under this parameter, the bonding force between the powder and the quartz can be satisfied, the uniformity of the powder thickness can be effectively guaranteed, and the state of the quartz surface after the spraying treatment can be more superior, the porosity is smaller, and the hardness of the sprayed layer is harder.

[0058] In the above step S4, during the spraying process, the distance between the nozzle of the spraying equipment used and the surface of the quartz bell jar is 15 cm.

[0059] After the surface of the quartz bell is sprayed with Y2O3, the quartz adhesion debris and quartz sharp edges on the quartz surface are completely covered by the formed coating. After Y2O3 spraying, the quartz surface roughness is more uniform and the defects are also optimized. After Y2O3 spraying, the product performance is significantly improved, which greatly improves the yield of wafer processing in this chamber.

[0060] Finally, the sprayed Dome (quartz bell jar) is subjected to high-pressure water washing, ultrasonic cleaning and baking in a clean room.

[0061] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for extending the service life of a quartz bell jar of a PVD device, characterized in that: Includes steps: S1, cleaning the quartz bell jar for the first time; S2, sandblasting the quartz bell jar; S3, cleaning the quartz bell jar for the second time; S4, spraying the quartz bell jar to form a coating on the surface of the quartz bell jar; Wherein, in step S4, Y2O3 powder is used to spray the quartz bell jar.

2. The method for extending the service life of a quartz bell jar of a PVD device according to claim 1, characterized in that: In step S4, the spraying thickness is 150-200 um.

3. The method for extending the service life of a quartz bell jar of a PVD device according to claim 1, characterized in that: In step S4, the spraying gas pressure is 2.0-3.0 MPa.

4. The method for extending the service life of a quartz bell jar of a PVD device according to any one of claims 1 to 3, characterized in that: In the step S2, white corundum is used as the sandblasting material, and the mesh number of the sand material is 24#.

5. The method for extending the service life of a quartz bell jar of a PVD device according to any one of claims 1 to 3, characterized in that: In step S2, the sandblasting gas pressure is 0.3-0.4 MPa.

6. The method for extending the service life of a quartz bell jar of a PVD device according to any one of claims 1 to 3, characterized in that: In the step S2, when the quartz bell jar is sandblasted, the incident angle formed by the blasting direction and the surface of the quartz bell jar is 45° to 90°.

7. The method for extending the service life of a quartz bell jar of a PVD device according to any one of claims 1 to 3, characterized in that: In step S2, the distance between the nozzle of the sandblasting equipment and the surface of the quartz bell jar is 15 cm.

8. The method for extending the service life of a quartz bell jar of a PVD device according to any one of claims 1 to 3, characterized in that: In step S4, the distance between the nozzle of the spraying equipment and the surface of the quartz bell jar is 15 cm.

9. The method for extending the service life of a quartz bell jar of a PVD device according to any one of claims 1 to 8, characterized in that: In the step S4, a protective jig is used to shield the sealing surface of the quartz bell jar, and the protective jig is made of stainless steel.

10. The method for extending the service life of a quartz bell jar of a PVD device according to any one of claims 1 to 9, characterized in that: In the step S2, a protective jig is used to shield the sealing surface of the quartz bell jar.

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