A diamond machining apparatus

Abstract

This utility model relates to a diamond processing apparatus, including a reaction chamber with an internal transmission space. The reaction chamber includes an automatic microwave distribution device for adjusting microwave reflection power. A microwave generator for providing an energy source is externally connected to the reaction chamber. Microwave energy is transmitted along the length of the reaction chamber. A reaction tube is vertically inserted into the reaction chamber, including an inlet and an outlet. The diameter D1 of the reaction chamber and the diameter D2 of the reaction tube satisfy: D1 = 1.1D2 ~ 1.3D2, so that the microwave energy passing through the reaction tube, under the action of a preset microwave power, ionizes and breaks down the etching gas entering the reaction tube through the inlet, forming a plasma jet. A molybdenum holder is provided below the outlet of the reaction tube for placing the diamond to be processed. The plasma jet can etch the diamond to be processed. This utility model generates a concentrated, downward-spraying plasma jet with concentrated energy distribution by inserting a reaction tube perpendicular to the reaction chamber and a smaller diameter inside the reaction chamber, resulting in high energy utilization during the etching process.

Description

Technical Field

[0001] This utility model relates to the field of diamond processing technology, and specifically to a diamond processing device. Background Technology

[0002] Microwave plasma chemical vapor deposition (MPCVD) is currently the most ideal method for producing high-quality, large-area diamonds because it avoids the introduction of impurities. However, during growth, defects such as amorphous carbon, impurities, or microcracks caused by growth stress may remain on the seed crystal surface. Therefore, it is necessary to eliminate these defects to improve the material quality.

[0003] To address these defects, existing technologies employ physical grinding or microwave plasma etching. Physical grinding, as disclosed in Chinese utility model patent ZL202023287245.7 (publication number CN215357784U), "A Diamond Grinding and Polishing Integrated Processing Equipment," involves using a grinding wheel to physically grind and eliminate surface cracks and other defects. However, this method easily leaves scratches on the diamond surface, affecting its physical and optical properties. Microwave plasma etching utilizes a device similar to that described in publication number CN116939939A. This device typically includes a microwave cavity comprising a resonant cavity and a vacuum cavity. The resonant cavity is connected to a microwave mode converter and the vacuum cavity at its two ends. The microwave mode converter has a microwave antenna extending into the resonant cavity. A quartz window isolates the resonant cavity from the vacuum cavity. The microwave mode converter, resonant cavity, and vacuum cavity are sequentially distributed along the axial direction H of the vacuum cavity. The microwave power source emitted by the microwave generator is coupled to the microwave mode converter. The TEM wave in the coaxial line is coupled into the resonant cavity of the cylindrical cavity through the microwave antenna to form the TM01 mode in the circular waveguide. Then, it is coupled to the vacuum cavity through the quartz window to generate plasma.

[0004] When the aforementioned microwave plasma device is applied to the etching of diamond surfaces, it avoids the scratches left by physical grinding, thus ensuring the physical and optical properties of the diamond. However, the plasma generated within the device is in the form of plasma spheres, which have a relatively dispersed energy distribution and low utilization rate of microwave energy, thereby affecting the etching rate of the diamond. Therefore, further improvements to the diamond processing device are needed. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a diamond processing device with a high etching rate, in view of the above-mentioned existing technology.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: the diamond processing device includes:

[0007] The reaction chamber has a transmission space inside, and the reaction chamber includes an automatic microwave adjustment device for adjusting microwave reflection power.

[0008] A microwave generator is externally connected to the reaction chamber and can be used to provide an energy source; microwave energy is transmitted along the length of the reaction chamber.

[0009] Its characteristic is that it also includes:

[0010] A reaction tube, vertically inserted into the reaction chamber, includes an inlet and an outlet. The diameter of the reaction chamber is D1, and the diameter of the reaction tube is D2. The relationship between D1 and D2 satisfies: D1 = 1.1D2 ~ 1.3D2, so that the microwaves passing through the reaction tube can ionize and break down the etching gas entering the reaction tube through the inlet under the action of a preset microwave power, forming a plasma jet.

[0011] A molybdenum holder is used to hold the diamond to be processed. The molybdenum holder is located below the outlet of the reaction tube. The aforementioned plasma jet can etch the diamond to be processed.

[0012] To coordinate the adjustment of microwave reflectivity, the automatic microwave distribution device includes a first regulator located on the left side of the reaction tube for adjusting the microwave reflectivity at the beginning of the reaction chamber, and a second regulator located on the right side of the reaction tube for adjusting the microwave reflectivity at the end of the reaction chamber. During the etching process, when the microwave reflectivity is too high, the microwave energy loss is significant. By placing the first regulator at the beginning of the reaction chamber and the second regulator at the end, the microwave reflectivity can be adjusted in a coordinated manner, thereby controlling the microwave reflectivity within a lower range, resulting in higher microwave energy utilization.

[0013] To ensure effective microwave transmission and plasma etching, the reaction chamber preferably includes a first regulator arranged from left to right with its end openings sequentially joined and fixed; a coupler for integrating and distributing microwave energy; a connector for conducting microwave energy; and a second regulator. The first regulator, coupler, connector, and second regulator are sequentially connected and form a space within the chamber for microwave transmission. Microwaves are transmitted from left to right within this space under the action of a microwave generator. The first and second regulators respectively adjust the microwave reflection power at the beginning and end of the reaction chamber, ensuring efficient utilization of microwave energy. The coupler integrates microwave energy to precisely control plasma activity and balance the etching rate. The connector directionally conducts microwave energy, allowing microwaves to pass through the tube wall of the reaction tube and excite the etching gas to generate plasma.

[0014] To achieve precise and flexible impedance adjustment, preferably, the top surface of the first regulator is provided with three spaced-apart first adjustment elements. Each first adjustment element can move independently in the vertical direction to adjust the impedance, thereby adjusting the microwave reflection power at the front end of the reaction chamber. Specifically, the first adjustment element is used to adjust the reactive component to offset the reactive portion of the load; the second adjustment element is used to adjust the resistive component; and the third adjustment element is used to further fine-tune the reactance and / or resistance, compensating for any residual mismatch after the adjustments made by the first two adjustment elements, thus achieving a more precise match.

[0015] For ease of monitoring, preferably, the top surface of the coupler is provided with at least two interfaces at intervals. These interfaces include a first interface for monitoring incident power and an external power meter, and a second interface for monitoring reflected power. The incident power reflects the actual output of the microwave source, ensuring stable energy input; the reflected power reflects the impedance stability of the plasma. The second interface is connected to an external power meter. By monitoring the incident power and reflected power, respectively, the first and second interfaces allow for timely fault detection and adjustment.

[0016] To improve the stability of the reaction tube vertically inserted into the reaction chamber, preferably, the bottom of the connector has a partially downward protruding portion to form a receiving part for receiving the reaction tube. The connector also has a channel for inserting the reaction tube, and the receiving part has an opening that communicates with the channel. The outlet of the reaction tube is flush with the opening, and the inlet of the reaction tube is exposed outside the channel. The channel for inserting the reaction tube in the connector and the receiving part design allow for more stable installation of the reaction tube. Furthermore, the opening in the receiving part that communicates with the channel allows the plasma jet to etch the diamond to be processed.

[0017] For ease of adjustment, preferably, a second adjusting element is provided on the right side of the second regulator. This second adjusting element can move laterally to change the impedance, thereby adjusting the microwave reflection power at the rear end of the reaction chamber. The second regulator is fixed to the rear of the connector with screws, and the impedance can be dynamically adjusted by moving the second adjusting element laterally, thus achieving efficient microwave energy transmission.

[0018] To facilitate control of the etching rate, preferably, the reaction tube includes a head with the inlet and a body with the outlet. The head has a slot for the body to be inserted into, and the relative distance between the body and the head in the vertical direction can be changed by means of the slot. The wall of the body is inserted into the slot of the head, and the relative distance between the body and the head can be adjusted vertically using a clamp, thereby changing the distance between the outlet and the end of the reaction tube, and ultimately controlling the etching rate by adjusting the length of the plasma jet.

[0019] To balance the etching rate, preferably, the etching gas includes oxygen and argon, with the volume V1 of oxygen and the volume V2 of argon satisfying: V1:V2 = 1:70 to 1:150. Oxygen decomposes into highly reactive oxygen atoms, oxygen ions, and ozone, which react with carbon atoms on the diamond surface to generate volatile products for chemical etching. Argon, as an inert gas, can form a stable plasma. When V1:V2 < 1:70, the oxygen concentration is too high, resulting in a rapid etching rate. Overheating of the plasma causes thermal damage to the diamond surface, and excessive etching increases the surface roughness. When V1:V2 > 1:150, the oxygen is diluted by the argon, resulting in a low oxygen concentration and a slow etching rate, leading to low process efficiency.

[0020] Compared with the prior art, the advantages of this utility model are as follows: when the microwave generator provides the energy source, by inserting a reaction tube perpendicular to the reaction chamber and with a small diameter in the reaction chamber, the spherical plasma in the original vacuum state is transformed into a plasma jet that is concentrated and sprayed downward. The energy distribution of the plasma jet is concentrated, the microwave energy utilization rate is high, and while retaining chemical etching, the high-energy ions in the plasma can also achieve additional etching effect by impacting the surface of the diamond to be processed. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present utility model;

[0022] Figure 2 This is a top view of an embodiment of the present invention (reaction tube omitted);

[0023] Figure 3 This is a bottom view of an embodiment of the present utility model;

[0024] Figure 4 This is a cross-sectional schematic diagram of an embodiment of the present utility model.

[0025] In the diagram: 1. Reaction chamber; 111. First regulator; 1111. First regulating component; 112. Second regulator; 1121. Second regulating component; 12. Coupler; 121. Interface; 1211. First interface; 1212. Second interface; 13. Connector; 131. Socket; 132. Receiving part; 2. Microwave generator; 3. Reaction tube; 31. Inlet; 32. Outlet; 33. Head; 331. Slot; 34. Tube body; 4. Molybdenum support; A. Diamond to be processed. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] like Figures 1 to 4The diagram shows the preferred embodiment of this utility model. The diamond processing apparatus includes a reaction chamber 1 with an internal transmission space and a microwave generator 2 connected to the reaction chamber 1 to provide an energy source. The reaction chamber 1 is equipped with an automatic microwave distribution device for adjusting microwave reflection power. A reaction tube 3 is vertically inserted into the reaction chamber 1. The top of the reaction tube 3 has an inlet 31 for introducing etching gas, and the bottom has an outlet 32 ​​for ejecting a plasma jet. A molybdenum support 4 is located below the outlet 32 ​​of the reaction tube 3 and can hold the diamond A to be processed. The diameter of the reaction chamber is D1, and the diameter of the reaction tube is D2. The relationship between D1 and D2 satisfies: D1 = 1.1D2 ~ 1.3D2. When D1 < 1.1D2, the diameter of the reaction tube 3 is too large, which will elongate the electric field distribution and reduce the electric field strength in the central region of the reaction tube. If the plasma density is insufficient, the flow rate of the etching gas entering the reaction tube 3 at a certain flow rate will slow down, and the rate at which the plasma jet etches the diamond A to be processed will also slow down. When D1>1.3D2, the diameter of the reaction tube is too small, and the microwave energy will leave from both sides of the tube wall of the reaction tube 3, resulting in energy loss. Therefore, in this embodiment, D1=1.2D2 is preferred, so that the microwave energy passing through the reaction tube 3 can ionize and break down the etching gas entering the reaction tube 3 through the inlet 31 under the action of the preset microwave power, and form a plasma jet, thereby etching the diamond A to be processed. Compared with the plasma sphere generated in the vacuum cavity in the prior art, the energy distribution of the plasma jet is more concentrated and the energy utilization rate is higher. In addition, it should be noted that the material of the reaction tube 3 in this embodiment is preferably quartz material that is easy for microwave penetration.

[0028] refer to Figure 4 The reaction chamber 1 extends laterally, and microwaves are transmitted from left to right within the reaction chamber 1. The reaction tube 3 is vertically mounted on the reaction chamber 1, and the etching gas is transmitted from top to bottom. When the microwave transmission direction is parallel to the movement direction of the etching gas, the high-speed flow of the gas will cause uneven distribution of microwave energy. The vertical design can reduce the influence of the etching gas on the microwave energy, allowing the microwave energy to be coupled into the gas more evenly, improving ionization efficiency, and thus forming a more uniform plasma.

[0029] To ensure effective microwave transmission and plasma etching, refer to... Figure 2 and Figure 3In this embodiment, the reaction chamber 1 includes a first regulator 111, a coupler 12, a connector 13, and a second regulator 112 connected sequentially from left to right. The four components form a space for microwaves to be transmitted from left to right. The first regulator 111 and the second regulator 112 respectively adjust the microwave reflection power at the head and tail of the reaction chamber 1, thereby ensuring that microwave energy is used efficiently. The coupler 12 integrates microwave energy to precisely control plasma activity and balance the etching rate. The connector 13 can directionally conduct microwave energy, so that microwaves can pass through the reaction tube 3 and excite the etching gas to generate plasma.

[0030] When microwave reflection power is abnormal, it can cause energy waste and equipment damage. (Refer to...) Figure 2 and Figure 4 In this embodiment, the first regulator 111 is preferably a three-pin regulator. The three spaced-apart first regulators 1111 on its top surface are three pins. Each pin can move independently in the vertical direction to adjust the impedance and thus adjust the microwave reflection power at the front end of the reaction chamber 1. The first pin is used to adjust the reactance component to offset the reactance part in the load; the second pin is used to adjust the resistance component; and the third pin is used to further fine-tune the reactance and / or resistance to compensate for the residual mismatch after the adjustment of the first two pins and achieve a more accurate match.

[0031] refer to Figure 2 In this embodiment, the coupler 12 preferably has four interfaces 121, including a first interface 1211 for monitoring incident power and a second interface 1212 connected to a power meter for monitoring reflected power. The incident power reflects the actual output of the microwave source, ensuring stable energy input. The reflected power reflects the impedance stability of the plasma. The power meter acquires the amplitude and phase information of the reflection coefficient and then calculates the load impedance based on this information. At this point, it is necessary to adjust the three-pin regulator and the short-circuit piston for real-time, fast, and stable automatic impedance matching, thereby improving the utilization rate of microwave energy. The first interface 1211 and the second interface 1212 monitor the incident power and reflected power, respectively, so that faults can be detected and adjusted in a timely manner. In addition, a third interface for forward coupling and a fourth interface for reverse coupling are also included, which are normally closed.

[0032] refer to Figure 4The bottom of the connector 13 is partially protruding downward to form a receiving part 132 for receiving the reaction tube 3. The connector 13 is also provided with a channel for inserting the reaction tube 3. The receiving part 132 is provided with an opening 131 that communicates with the channel. The outlet 32 ​​of the reaction tube 3 is flush with the opening 131. The inlet 31 of the reaction tube 3 is exposed outside the channel. The receiving part 132 can provide a more stable installation for the reaction tube 3. Furthermore, the opening 131 in the receiving part 132 that communicates with the channel allows the plasma jet to etch the diamond A to be processed. The reaction tube 3 includes a head 33 with an inlet 31 and a tube body 34 with an outlet 32. The head 33 has a slot 331 for inserting the tube body 34. The tube wall of the tube body 34 is inserted into the slot 331 of the head 33. The relative distance between the tube body 34 and the head 33 can be adjusted up and down using a clamp, thereby changing the distance between the outlet 32 ​​and the end of the reaction tube 3. Finally, the etching rate can be controlled by adjusting the length of the plasma jet.

[0033] refer to Figures 2 to 4 In this embodiment, the second regulator 112 is fixed to the rear end of the connector 13 by screws, and the second regulator 112 is preferably a short-circuit piston. A second regulating member 1121 is provided on the right side of the short-circuit piston, which can move laterally to change the impedance and thus adjust the microwave reflection power at the rear end of the reaction chamber 1. By moving the second regulating member 1121 laterally, the impedance can be dynamically adjusted, thereby achieving efficient transmission of microwave energy.

[0034] The etching gas in reaction tube 3 includes oxygen and argon. Oxygen decomposes into highly reactive oxygen atoms, oxygen ions, and ozone, which react with carbon atoms on the diamond surface to generate volatile products for chemical etching. Argon, as an inert gas, can form a stable plasma. When V1:V2 < 1:70, the oxygen concentration is too high, resulting in a fast etching rate. Overheating of the plasma causes thermal damage to the diamond surface, and excessive etching increases the roughness of the diamond surface. When V1:V2 > 1:150, the oxygen is diluted by the argon. At this point, the oxygen concentration is too low, resulting in a slow etching rate and low process efficiency. Therefore, in this embodiment, the preferred ratio of oxygen to argon is V1:V2 = 1:110.

[0035] The working principle of the diamond processing device in this embodiment is as follows: The diamond A to be processed is placed on the molybdenum support 4, and an etching gas is introduced into the reaction tube 3. The etching gas includes oxygen and argon in a ratio of V1:V2 = 1:110. The microwave generator 2 is turned on and the power is set to 500W. At this time, the strongest electric field is concentrated in the center of the reaction tube 3 (i.e., the area where the reaction tube 3 overlaps with the reaction chamber 1). After the etching gas is ionized and broken down by the microwave, a highly active plasma jet is formed, which etches the diamond A to be processed through a chemical reaction. At this time, the position of the diamond A to be processed is adjusted. Position the device directly below the plasma jet and increase the microwave power to 1500W. Observe the reading of the power meter connected to the second interface 1212 of the coupler 12. The reflected power needs to be maintained between 80W and 100W. When the reflected power is less than 80W or greater than 100W, the three pins of the first regulator 111 and the second regulator 1121 of the second regulator 112 need to be adjusted together until the reading on the power meter is maintained between 80W and 100W. After etching for 1 hour, turn off the microwave generator 2 and the etching gas. Remove the diamond to complete the operation.

Claims

1. A diamond processing apparatus, comprising: The reaction chamber (1) has a transmission space inside, and the reaction chamber (1) includes an automatic microwave adjustment device for adjusting microwave reflection power; A microwave generator (2) is externally connected to the reaction chamber (1) and can be used to provide an energy source. Microwave energy is transmitted along the length of the reaction chamber (1). Its features are: It also includes: The reaction tube (3) is vertically inserted into the reaction chamber (1) and includes an inlet (31) and an outlet (32). The diameter of the reaction chamber (1) is D1 and the diameter of the reaction tube (3) is D2. The relationship between D1 and D2 satisfies: D1 = 1.1D2 ~ 1.3D2, so that the microwave energy passing through the reaction tube (3) can ionize and break down the etching gas entering the reaction tube (3) through the inlet (31) under the action of the preset microwave power and form a plasma jet. A molybdenum holder (4) is used to hold the diamond (A) to be processed. The molybdenum holder (4) is located below the outlet (32) of the reaction tube (3). The aforementioned plasma jet can etch the diamond (A) to be processed.

2. The diamond processing apparatus according to claim 1, characterized in that: The microwave automatic adjustment device includes a first regulator (111) located on the left side of the reaction tube (3) for adjusting the microwave reflectivity at the head end of the reaction chamber (1) and a second regulator (112) located on the right side of the reaction tube (3) for adjusting the microwave reflectivity at the tail end of the reaction chamber (1).

3. The diamond processing apparatus according to claim 2, characterized in that: The reaction chamber (1) includes a first regulator (111) arranged from left to right with its end openings sequentially assembled and fixed, a coupler (12) for integrating and distributing microwave energy, a connector (13) for conducting microwave energy, and a second regulator (112).

4. The diamond processing apparatus according to claim 3, characterized in that: The top surface of the first regulator (111) is provided with three spaced-apart first adjustment members (1111), each of which can move independently in the vertical direction to adjust the impedance and thus adjust the microwave reflection power at the front end of the reaction chamber (1).

5. The diamond processing apparatus according to claim 3, characterized in that: The top surface of the coupler (12) is provided with at least two interfaces (121) spaced apart. The interfaces (121) include a first interface (1211) for connecting an external power meter and monitoring incident power and a second interface (1212) for monitoring reflected power.

6. The diamond processing apparatus according to claim 3, characterized in that: The bottom of the connector (13) is partially protruding downward to form a receiving part (132) for receiving the reaction tube (3). The connector (13) is also provided with a channel for inserting the reaction tube (3). The receiving part (132) is provided with an opening (131) that communicates with the channel. The outlet (32) of the reaction tube (3) is flush with the opening (131). The inlet (31) of the reaction tube (3) is exposed outside the channel.

7. The diamond processing apparatus according to claim 3, characterized in that: A second adjustment member (1121) is provided on the right side of the second regulator (112). The second adjustment member (1121) can move laterally to change the impedance and thereby adjust the microwave reflection power at the rear end of the reaction chamber (1).

8. The diamond processing apparatus according to claim 1, characterized in that: The reaction tube (3) includes a head (33) with the inlet (31) and a tube body (34) with the outlet (32). The head (33) is provided with a slot (331) for the tube body (34) to be inserted into. The tube body (34) and the head (33) can change their relative distance in the vertical direction by means of the slot (331).

9. The diamond processing apparatus according to any one of claims 1 to 8, characterized in that: The etching gas includes oxygen and argon, and the volume V1 of oxygen and the volume V2 of argon satisfy: V1:V2 = 1:70 to 1:150.

Images