Vacuum cavity structure for graphite boat dry etching

Abstract

The utility model discloses a vacuum cavity structure for graphite boat dry etching, which comprises a stainless steel cylindrical vacuum cavity, and a stainless steel support rod is mounted in the vacuum cavity. According to the utility model, the vacuum cavity is cylindrical, the graphite boat is placed at the fixed position of the support rod in the vacuum cavity, the graphite boat is respectively butted with the electrode tube joint in the vacuum cavity, the cavity door mechanism is closed, the heating tube is heated, and the vacuum pump set is started to vacuumize after the set temperature value is reached; after the vacuum degree in the vacuum cavity detected by the vacuum gauge reaches a set vacuum degree, argon is introduced into the remote plasma power supply and ignition is carried out, NF3 is introduced after the remote plasma power supply is successfully ignited, the remote plasma power supply begins to ionize the NF3, formed plasma enters the vacuum cavity, etching cleaning is carried out on the graphite boat, and the graphite boat is obtained. By means of the mode and the cylindrical vacuum cavity, powder generated by corrosion of the cavity wall due to accumulation of etching compounds is effectively reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of graphite boat dry etching equipment, in particular to a vacuum cavity structure used for graphite boat dry etching. Background Art

[0002] In the PECVD (Plasma Enhanced Chemical Vapor Deposition) process in the photovoltaic industry, the graphite boat, as a loading fixture, will form a thicker film layer on the surface after multiple coating processes, thereby reducing the conversion rate of the wafer. Therefore, the graphite boat needs to be cleaned after a certain number of uses to remove the surface film layer.

[0003] The traditional method of cleaning graphite boats is wet cleaning, which uses hydrofluoric acid to clean, then pure water to clean, and then dry. The whole process is time-consuming and polluting. In recent years, a dry cleaning process using plasma equipment has emerged. Compared with traditional wet cleaning, it uses process gas ionization to generate plasma to physically bombard and chemically react with the film layer on the surface of the graphite boat. The process is time-consuming and less polluting.

[0004] However, some plasma equipment is made of aluminum, and most of the cavities of the plasma equipment are set to be square. However, when using the square aluminum cavity for dry cleaning, the cavity wall will corrode due to the accumulation of etching compounds to produce powder, which will contaminate the graphite boat. Therefore, we need to propose a vacuum cavity structure for dry etching of graphite boat to solve the above problems. Utility Model Content

[0005] The purpose of the utility model is to provide a vacuum chamber structure for dry etching of a graphite boat. By setting the vacuum chamber to a cylindrical shape, through the coordination of a remote plasma power supply, a heating rod, a vacuum pipe and a vacuum pump group, and in combination with the cylindrical vacuum chamber, the corrosion of the chamber wall due to the accumulation of etching compounds to produce powder is effectively reduced, thereby improving the quality of graphite boat cleaning, so as to solve the problems raised in the background technology.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a vacuum chamber structure for graphite boat dry etching, comprising a stainless steel cylindrical vacuum chamber, a stainless steel support rod is installed inside the vacuum chamber, a graphite boat is arranged on the support rod, a chamber door mechanism is installed at one end of the vacuum chamber, a plurality of groups of heating tubes are installed inside the vacuum chamber, and the plurality of groups of heating tubes are evenly distributed on the periphery of the graphite boat, a rear end cover is installed at the other end of the vacuum chamber, and a heating rod joint is installed at one end of the heating tube, and the heating rod joint is installed on the rear end cover, and two electrode tube joints connected to the graphite boat and a vacuum gauge connected to the vacuum chamber are also installed on the rear end cover, a plurality of remote plasma power supplies for generating plasma are connected to the upper end of the vacuum chamber, a vacuum pumping pipe is connected to the lower end of the vacuum chamber, and a vacuum pumping group is connected to one end of the vacuum pumping pipe.

[0007] Preferably, two groups of support rods are provided, and the two groups of support rods are fixed in parallel to the inner bottom of the vacuum chamber, the graphite boat is placed on the two groups of support rods, and one end of the graphite boat is provided with an electrode hole for plugging two electrode pipe joints.

[0008] Preferably, the outside of the support rod is sleeved with a Teflon sleeve, the length of the Teflon sleeve is longer than the length of the graphite boat support leg, end flanges are provided at both ends of the vacuum chamber, supports are fixed on the inner circles of the end flanges at both ends of the vacuum chamber, and the two ends of the support rod are respectively fixed on the supports at both ends of the vacuum chamber.

[0009] Preferably, the chamber door mechanism and the rear end cover plate are respectively mounted on end face flanges at both ends of the vacuum chamber, a water cooling groove is provided on the end face flange, and one side of the water cooling groove is connected to a water cooling mechanism.

[0010] Preferably, the cavity door mechanism comprises a cavity door, a sealing groove is provided on a side of the cavity door close to the end face flange, a sealing ring is placed in the sealing groove, and the cavity door is sealed with the end face flange when the cavity door is closed.

[0011] Preferably, two observation windows are provided in the middle of the rear end cover plate, and the two observation windows are located on both sides of the electrode tube joint.

[0012] Preferably, the vacuum pipeline includes a main pipe and multiple branch pipes, the multiple branch pipes are connected to the main pipe, one end of the main pipe is connected to the vacuum pump group, the multiple remote plasma power supplies are staggered in upper and lower positions with the multiple branch pipes, and one end of the remote plasma power supply is connected to an air inlet pipe.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] 1. The utility model sets the vacuum chamber to be cylindrical, puts the graphite boat into the fixed position of the support rod in the vacuum chamber, that is, on the Teflon sleeve, connects the graphite boat to the electrode pipe joints in the vacuum chamber, closes the chamber door mechanism, heats the heating tube to increase the temperature, starts the vacuum pump group to evacuate after reaching the set temperature value, and after the vacuum meter detects that the vacuum degree in the vacuum chamber reaches the set vacuum degree, the remote plasma power supply introduces argon and ignites, and after the remote plasma power supply is successfully ignited, NF3 is introduced, and the remote plasma power supply starts to ionize NF3, and the formed plasma enters the vacuum chamber to etch and clean the graphite boat. In this way, combined with the cylindrical vacuum chamber, the corrosion of the chamber wall due to the accumulation of etching compounds to produce powder is effectively reduced, thereby improving the cleaning quality of the graphite boat.

[0015] 2. The utility model sets an electrode tube joint, through which an external medium frequency power supply is connected. The external medium frequency power supply applies an electric field to the graphite boat through the electrode tube joint, further performing secondary ionization on the plasma and residual gas in the vacuum chamber, thereby improving the ionization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model;

[0017] Figure 2 It is a schematic diagram of the cross-sectional structure of the utility model;

[0018] Figure 3 It is a side structural schematic diagram of the utility model.

[0019] In the figure: 1. Remote plasma power supply; 2. Vacuum chamber; 3. Graphite boat; 4. Support rod; 5. Electrode tube joint; 6. Heating tube; 7. Vacuum gauge; 8. Vacuum extraction pipeline; 9. Vacuum pump group; 10. Chamber door mechanism; 11. Rear end cover plate; 12. Heating rod joint; 13. Observation window. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] See also Figure 1-3The utility model provides a technical solution: a vacuum chamber structure for graphite boat dry etching, comprising a stainless steel cylindrical vacuum chamber 2, a stainless steel support rod 4 is installed inside the vacuum chamber 2, a graphite boat 3 is arranged on the support rod 4, a chamber door mechanism 10 is installed at one end of the vacuum chamber 2, a plurality of groups of heating tubes 6 are installed inside the vacuum chamber 2, and the plurality of groups of heating tubes 6 are evenly distributed on the periphery of the graphite boat 3, a rear end cover plate 11 is installed at the other end of the vacuum chamber 2, and a heating rod joint 12 is installed at one end of the heating tube 6, and the heating rod joint 12 is installed on the rear end cover plate 11, and two electrode tube joints 5 connected to the graphite boat 3 and a vacuum gauge 7 connected to the vacuum chamber 2 are also installed on the rear end cover plate 11, a plurality of remote plasma power supplies 1 for generating plasma are connected to the upper end of the vacuum chamber 2, a vacuum pumping pipe 8 is connected to the lower end of the vacuum chamber 2, and a vacuum pump group 9 is connected to one end of the vacuum pumping pipe 8.

[0022] When in use, the graphite boat 3 is placed in a fixed position on the support rod 4 in the vacuum chamber 2, the two electrode holes of the graphite boat 3 are respectively connected to the electrode pipe joint 5 in the vacuum chamber 2, the chamber door is closed, and the heating tube 6 is heated and heated. When the temperature in the vacuum chamber 2 reaches the set temperature value, the vacuum pump group 9 is started to evacuate the vacuum. After the vacuum meter 7 detects that the vacuum degree in the vacuum chamber 2 reaches the set vacuum degree, the remote plasma power supply 1 introduces argon Ar and ignites. After the remote plasma power supply 1 is successfully ignited, NF3 is introduced. The remote plasma power supply 1 starts to ionize NF3, and the formed plasma enters the vacuum chamber 2 to etch and clean the graphite boat 3. The external intermediate frequency power supply applies an electric field to the graphite boat 3 through the electrode pipe joint 5, further ionizes the plasma in the vacuum chamber 2, improves the ionization rate, makes the plasma concentration in the vacuum chamber 2 higher, and accelerates the cleaning rate of the graphite boat 3. The plasma reacts chemically with the silicon nitride coating on the surface of the graphite boat 3 to generate gaseous compounds, which are discharged through the vacuum pipe 8, and finally the process of removing the silicon nitride coating on the surface of the graphite boat 3 is achieved. In combination with the cylindrical vacuum chamber 2, the corrosion of the chamber wall due to the accumulation of etching compounds to produce powder is effectively reduced, thereby improving the cleaning quality of the graphite boat 3.

[0023] Two groups of support rods 4 are provided, and the two groups of support rods 4 are fixed in parallel on the inner bottom of the vacuum chamber 2. The graphite boat 3 is placed on the two groups of support rods 4, and one end of the graphite boat 3 is provided with electrode holes for plugging in two electrode pipe joints 5, so as to facilitate external connection of an intermediate frequency power supply through the electrode pipe joint 5. The external intermediate frequency power supply applies an electric field to the graphite boat 3 through the electrode pipe joint 5, so as to further ionize the plasma in the vacuum chamber 2 and improve the ionization rate.

[0024] The outside of the support rod 4 is sleeved with a Teflon sleeve, the length of the Teflon sleeve is longer than the length of the legs of the graphite boat 3, end flanges are provided at both ends of the vacuum chamber 2, and supports are fixed on the inner circles of the end flanges at both ends of the vacuum chamber 2. The two ends of the support rod 4 are respectively fixed on the supports at both ends of the vacuum chamber 2, and the Teflon sleeve is used for insulation, so that when the graphite boat 3 is placed in the vacuum chamber 2, the four contact legs are just placed on the Teflon, avoiding conduction between the graphite boat 3 and the support rod 4.

[0025] The chamber door mechanism 10 and the rear end cover plate 11 are respectively installed on the end face flanges at both ends of the vacuum chamber 2. A water cooling groove is opened on the end face flange. One side of the water cooling groove is connected to a water cooling mechanism. The water cooling mechanism consists of a water pump and a water tank. The water pump is connected to the water tank and the water cooling groove through a water pipe, so that the water in the water tank can be transferred to the water cooling groove through the water pump to cool the end face flange, thereby cooling the two ends of the vacuum chamber 2.

[0026] The chamber door mechanism 10 includes a chamber door, and a sealing groove is provided on one side of the chamber door close to the end face flange. A sealing ring is placed in the sealing groove. When the chamber door is closed, it is sealed with the end face flange to improve the sealing performance of the connection between the chamber door and the end face flange.

[0027] Two observation windows 13 are provided in the middle of the rear end cover plate 11 . The two observation windows 13 are located on both sides of the electrode tube joint 5 and are used to observe the cleaning status of the graphite boat 3 inside the cavity.

[0028] The vacuum pipe 8 includes a main pipe and multiple branch pipes, the multiple branch pipes are connected to the main pipe, one end of the main pipe is connected to the vacuum pump group 9, and the multiple remote plasma power supplies 1 are staggered up and down with the multiple branch pipes to prevent the plasma injected by the remote plasma power supply 1 from being quickly drawn away by the branch pipes, thereby increasing the concentration of plasma in the vacuum chamber 2 so that the graphite boat 3 can be evenly etched.

[0029] It should be noted that the main reaction substance involved in the utility model is plasma, which includes free electrons, cations, anions, atoms / atomic groups, molecules, etc. The plasma reacts chemically with the silicon nitride coating on the surface of the graphite boat to generate corresponding gaseous compounds and other substances, such as NO2, NO / SIF4, etc.; the gaseous compounds and other substances generated after plasma treatment are discharged by the vacuum system, thereby removing the silicon nitride coating of the graphite boat.

[0030] Chemical reaction principle of silicon nitride coating:

[0031] SI3N4+(O+OF+CF3+CO+COF+F+e+……)→NO2↑+NO↑+SIF4↑

[0032] +……↑.

[0033] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A vacuum chamber structure for graphite boat dry etching, comprising a stainless steel cylindrical vacuum chamber (2), characterized in that: A support rod (4) made of stainless steel is installed inside the vacuum chamber (2), a graphite boat (3) is placed on the support rod (4), a chamber door mechanism (10) is installed at one end of the vacuum chamber (2), a plurality of groups of heating tubes (6) are installed inside the vacuum chamber (2), the plurality of groups of heating tubes (6) are evenly distributed on the periphery of the graphite boat (3), a rear end cover plate (11) is installed at the other end of the vacuum chamber (2), and a heating rod joint (12) is installed at one end of the heating tube (6). ), the heating rod joint (12) is installed on the rear end cover plate (11), and the rear end cover plate (11) is also equipped with two electrode pipe joints (5) connected to the graphite boat (3) and a vacuum gauge (7) connected to the vacuum chamber (2), the upper end of the vacuum chamber (2) is connected to a plurality of remote plasma power supplies (1) for generating and providing plasma, the lower end of the vacuum chamber (2) is connected to a vacuum pumping pipe (8), and one end of the vacuum pumping pipe (8) is connected to a vacuum pump group (9).

2. The vacuum chamber structure for graphite boat dry etching according to claim 1, characterized in that: The support rods (4) are provided in two groups, and the two groups of support rods (4) are fixed in parallel on the inner bottom of the vacuum chamber (2). The graphite boat (3) is placed on the two groups of support rods (4), and one end of the graphite boat (3) is provided with an electrode hole for plugging two electrode pipe joints (5).

3. The vacuum chamber structure for graphite boat dry etching according to claim 2, characterized in that: The support rod (4) is sleeved with a section of Teflon sleeve on the outside, the length of the Teflon sleeve is longer than the length of the support foot of the graphite boat (3), the two ends of the vacuum chamber (2) are provided with end face flanges, the inner circles of the end face flanges at the two ends of the vacuum chamber (2) are fixed with supports, and the two ends of the support rod (4) are respectively fixed on the supports at the two ends of the vacuum chamber (2).

4. The vacuum chamber structure for graphite boat dry etching according to claim 3, characterized in that: The chamber door mechanism (10) and the rear end cover plate (11) are respectively mounted on the end face flanges at both ends of the vacuum chamber (2); a water cooling groove is provided on the end face flange, and one side of the water cooling groove is connected to a water cooling mechanism.

5. The vacuum chamber structure for graphite boat dry etching according to claim 4, characterized in that: The chamber door mechanism (10) comprises a chamber door, a sealing groove is provided on one side of the chamber door close to the end face flange, a sealing ring is placed in the sealing groove, and the chamber door is sealed with the end face flange when closed.

6. The vacuum chamber structure for graphite boat dry etching according to claim 5, characterized in that: Two observation windows (13) are arranged in the middle of the rear end cover plate (11), and the two observation windows (13) are located on both sides of the electrode pipe joint (5).

7. The vacuum chamber structure for graphite boat dry etching according to claim 1, characterized in that: The vacuum extraction pipeline (8) comprises a main pipe and a plurality of branch pipes, the plurality of branch pipes are all connected to the main pipe, one end of the main pipe is connected to a vacuum pump group (9), the plurality of remote plasma power sources (1) are staggered up and down with the plurality of branch pipes, and one end of the remote plasma power source (1) is connected to an air inlet pipe.

Images