A method for growing large-size polycrystalline diamond by heterogeneous growth

Abstract

The invention discloses a growth method for heterogeneously grown large-size polycrystalline diamond, and relates to the technical field of chemical vapor deposition. A detachable substrate combination consisting of a molybdenum carrier and a stainless steel ring can be disassembled for easy cleaning, and the substrate combination can be efficiently and repeatedly recycled. The surface energy of the stainless steel ring is greatly different from that of a diamond deposition material, so that carbon atoms cannot be stably attached, and the temperature field in a preset diamond deposition target area is made more uniform, thereby solving the drawbacks of microwave systems in the polycrystalline diamond growth process. The stainless steel ring has a large difference in lattice matching with diamond, and a continuous and uniform crystal structure cannot be formed on the stainless steel ring, thereby avoiding the growth of polycrystalline diamond on the side edge of the molybdenum carrier, resulting in the inability of a wafer to detach or the chip being broken during the detachment process, and reducing the possibility of polycrystalline diamond grown on the molybdenum carrier being broken during the removal stage.

Description

Technical Field

[0001] The invention relates to the technical field of chemical vapor deposition, in particular to a growth method for heterogeneously growing large-size polycrystalline diamond. Background Art

[0002] Microwave plasma chemical vapor deposition technology is recognized as one of the ideal means to prepare large-sized high-quality single-crystal diamonds. Microwave plasma chemical vapor deposition technology is roughly that microwaves resonate through a specially designed resonant cavity to form a concentrated electric field in the area above the sample stage, dissociating raw gas such as hydrogen and methane to form atomic hydrogen and a series of carbon-containing precursor plasmas, and then depositing and growing diamonds on the surface of the seed crystal cooled to a certain temperature:

[0003] For example, the existing patent application number: 202410702675.4 provides a substrate stage system MPCVD device, including: a microwave reflection stage and a large molybdenum stage arranged in stacked order; a substrate stage, arranged on the side of the large molybdenum stage away from the microwave reflection stage; wherein an annular protrusion is provided on the side of the large molybdenum stage away from the microwave reflection stage, and the annular protrusion is coaxial with the substrate stage and surrounds the outer circumference of the substrate stage.

[0004] Taking the above-mentioned substrate table system MPCVD equipment as an example, the substrate table is the main supporting structure for diamond growth. However, there are gaps and depressions in the supporting structure around the substrate table. During the diamond growth process, diamonds and derivatives will be deposited in the gaps and depressions, making subsequent equipment cleaning more troublesome. In addition, the common substrate table is made of single crystal silicon wafer material, and the diamond wafer is detached by dissolving the substrate table with strong acid, resulting in large material loss and serious pollution. Summary of the invention

[0005] The object of the present invention is to provide a method for growing large-size heterogeneously grown polycrystalline diamond to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for growing large-size polycrystalline diamond by heterogeneous growth, comprising the following steps:

[0007] Step 1: Ultrasonic cleaning of substrate assembly;

[0008] Step 2: Purge and dry the substrate assembly with CDA;

[0009] Step 3: Place the substrate assembly on the MPCVD water cooling table;

[0010] Step 4: MPCVD equipment working;

[0011] Step 5: introducing deposition gas;

[0012] Step 6: Growth and deposition for a certain period of time;

[0013] Step 7: Cool down and exit the furnace;

[0014] Step 8: Polycrystalline diamond sheet separation;

[0015] The substrate assembly comprises a molybdenum carrier and a stainless steel ring sleeved on the outer side of the molybdenum carrier.

[0016] Preferably, the step 1 is as follows: ultrasonically clean the molybdenum carrier and the stainless steel ring in deionized water for 30 minutes to clean foreign matter and dirt on the molybdenum carrier and the stainless steel ring to prevent impurities on the substrate assembly from affecting the crystal quality.

[0017] Preferably, the step 2 is as follows: placing the molybdenum carrier plate and the stainless steel ring in a CDA environment for blowing and drying to remove surface moisture.

[0018] Preferably, the step three is specifically as follows: placing the molybdenum carrier into the stainless steel ring, completing the substrate assembly, and placing the substrate assembly on the MPCVD carrier water cooling table.

[0019] Preferably, the step 4 is specifically as follows:

[0020] Preparation: Close the MPCVD chamber and use a mechanical pump to evacuate the MPCVD chamber for 30 minutes to make the vacuum degree in the MPCVD chamber reach below 0.001 Torr;

[0021] Ignition: 300-500sccm hydrogen is introduced to maintain the pressure in the MPCVD chamber at about 6Torr, the microwave power is turned on, the power filament is preheated, and after the preheating is completed, the microwave is turned on and the microwave power is set to 1000W;

[0022] Heating: Adjust the MPCVD cavity pressure and microwave power to make the temperature in the MPCVD cavity reach between 600-800°C to complete the heating;

[0023] Adjust various parameters inside the MPCVD chamber to avoid reactions between the gases when the deposition gases are subsequently injected.

[0024] Preferably, the step five is specifically as follows:

[0025] Injection gas: 10-50sccm of methane is introduced into the MPCVD chamber, <0.5sccm of nitrogen is introduced into the MPCVD chamber, and 0.2-1sccm of oxygen is introduced into the MPCVD chamber;

[0026] Deposition environment control: fine-tune the MPCVD chamber pressure to maintain it at 120-180 Torr, fine-tune the microwave power to maintain it at 7000-9000W, and fine-tune the MPCVD chamber temperature to maintain it at 700-900℃;

[0027] The specific steps of step six are as follows: according to the target thickness of the polycrystalline diamond, the MPCVD operation is controlled to maintain the deposition environment achieved in step five for a certain period of time, and the polycrystalline diamond is slowly deposited and grown on the substrate combination.

[0028] Preferably, the step seven is specifically as follows:

[0029] Gas injection stop: stop the supply of methane, nitrogen and oxygen;

[0030] Slow cooling: Set the cooling, pressure relief and microwave power reduction time to 300 minutes, slowly cool down, extend the cooling cycle of the diamond sheet, reduce the material reaction of thermal expansion and contraction, and effectively reduce the occurrence of cracks in the diamond sheet;

[0031] Annealing: When the pressure in the MPCVD chamber reaches 3 Torr, the microwave power reaches 1000W, and the chip temperature is between 60-90 degrees, turn off the microwave power.

[0032] Preferably, step eight is as follows:

[0033] Cooling: Turn off the hydrogen and wait for the wafer to cool for 15 minutes;

[0034] Exhaust: Turn on the mechanical pump to remove the residual reaction gas in the chamber, so that the pressure in the MPCVD chamber reaches 0.01Torr;

[0035] Gas pressure control: nitrogen is injected into the MPCVD chamber to remove the vacuum environment from the MPCVD chamber. Nitrogen is injected after the crystal diamond is formed to reduce the possibility of chemical reaction of the crystal diamond sheet. The pressure in the MPCVD chamber reaches atmospheric pressure to avoid stress on the crystal diamond sheet caused by the pressure difference between the inside and outside of the MPCVD chamber, thereby reducing the possibility of cracks in the crystal diamond sheet.

[0036] Take out; withdraw the substrate assembly and take out the polycrystalline diamond.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The substrate assembly in the present application is composed of a molybdenum carrier and a stainless steel ring outside the molybdenum carrier. The detachable substrate assembly composed of the molybdenum carrier and the stainless steel ring can be disassembled, and the molybdenum carrier and the stainless steel ring are ultrasonically cleaned in deionized water for 30 minutes to directly and indirectly act on the dirt on the molybdenum carrier and the stainless steel ring, so that the fine dirt layer is dispersed, emulsified, and peeled off, and the molybdenum carrier and the stainless steel ring are thoroughly cleaned, and the substrate assembly can be efficiently recycled;

[0039] 2. The MPCVD working time in this application increases, and polycrystalline diamond slowly deposits and grows on the substrate combination, which is composed of a molybdenum carrier and a stainless steel ring outside the molybdenum carrier. Due to the edge discharge phenomenon in the application of the microwave system, the stainless steel ring will guide the secondary plasma field to the stainless steel. Since the deposition of diamond requires a suitable surface energy on the molybdenum carrier to facilitate the adsorption, decomposition and deposition of carbon atoms, the surface energy of the stainless steel ring is quite different from that of the diamond deposition material, resulting in the inability of carbon atoms to stably adhere, making the temperature field in the preset diamond deposition target area more uniform, solving the disadvantages of the microwave system in the polycrystalline diamond growth process, and improving the quality of polycrystalline diamond generated by microwave plasma chemical vapor deposition technology;

[0040] 3. In the present application, the stainless steel ring and the diamond lattice match are quite different, and a continuous and uniform crystal structure cannot be formed on the stainless steel ring, thereby avoiding the growth of polycrystalline diamond on the side edge of the molybdenum carrier, resulting in the inability to detach the wafer or the wafer breaking during the detachment process, thereby reducing the possibility of polycrystalline diamond grown on the molybdenum carrier breaking during the removal stage. The stainless steel ring is used as a traction ring in the MPCVD polycrystalline deposition process, and a graphite-like amorphous carbon substance is formed on the surface of the stainless steel ring. The substance will not adhere to the target polycrystalline diamond. During the cooling and annealing process of the substrate assembly, the air pressure, temperature, electric field and other parameters around the polycrystalline diamond are slowly changed to avoid the thermal stress change of the material caused by rapid cooling, which will cause the polycrystalline diamond to break, reduce the occurrence of polycrystalline diamond flakes formed on the molybdenum carrier, and effectively reduce the occurrence of cracks in the diamond flakes, solving the problem of flakes caused by side wall adhesion during the growth and detachment of the diamond. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the growth method of the present invention.

[0042] Figure 2 It is a schematic structural diagram of the substrate combination of the present invention.

[0043] Figure 3 It is a schematic diagram of the partial structure of the molybdenum carrier of the present invention.

[0044] Numbers in the figure: 1, molybdenum carrier plate; 2, stainless steel ring. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] Example: Figure 1-Figure 3 As shown, the present invention provides a technical solution for a method for growing large-size polycrystalline diamond by heterogeneous growth, comprising the following steps:

[0047] Step 1: Ultrasonic cleaning of substrate assembly;

[0048] Step 2: Purge and dry the substrate assembly with CDA;

[0049] Step 3: Place the substrate assembly on the MPCVD water cooling table;

[0050] Step 4: MPCVD equipment working;

[0051] Step 5: introducing deposition gas;

[0052] Step 6: Growth and deposition for a certain period of time;

[0053] Step 7: Cool down and return the furnace;

[0054] Step 8: Polycrystalline diamond sheet separation;

[0055] The substrate assembly comprises a molybdenum carrier plate 1 and a stainless steel ring 2 sleeved on the outer side of the molybdenum carrier plate 1 .

[0056] The specific steps of applying the above substrate combination to the growth method of polycrystalline diamond are as follows:

[0057] Step 1: Ultrasonic cleaning of the substrate assembly. The molybdenum carrier plate 1 and the stainless steel ring 2 are placed in deionized water for ultrasonic cleaning for 30 minutes. The cavitation, acceleration and straight-forward flow effects of ultrasound in the liquid are used to directly and indirectly act on the dirt on the molybdenum carrier plate 1 and the stainless steel ring 2, so that the fine dirt layer is dispersed, emulsified and peeled off, and the molybdenum carrier plate 1 and the stainless steel ring 2 are thoroughly cleaned to remove foreign matter and dirt on the substrate assembly composed of the molybdenum carrier plate 1 and the stainless steel ring 2, so as to avoid the presence of fine stains on the substrate assembly used for precipitation growth of polycrystalline diamond that affects the crystal quality.

[0058] Step 2: Purge and dry the substrate assembly with CDA. Place the molybdenum carrier 1 and the stainless steel ring 2 in a CDA environment for purge and drying to remove surface moisture. Use CDA gas, whose main components are nitrogen, oxygen and a small amount of rare gases, to dry the molybdenum carrier 1 and the stainless steel ring 2 to reduce the adhesion of gas and static electricity on the substrate assembly composed of the molybdenum carrier 1 and the stainless steel ring 2, ensure the stability of the surface chemical structure of the substrate assembly, and improve the stability of the combination of polycrystalline diamond and the substrate assembly.

[0059] Step 3: Place the substrate assembly on the MPCVD water-cooling table. First, place the molybdenum carrier 1 into the stainless steel ring 2, and then place the substrate assembly on the MPCVD medium-carrying water-cooling table. The detachable substrate assembly consisting of the molybdenum carrier 1 and the stainless steel ring 2 can be disassembled and thoroughly cleaned, and the substrate assembly can be efficiently reused.

[0060] Step 4: MPCVD equipment operation:

[0061] First, preparatory work is carried out. The MPCVD chamber is closed to isolate the MPCVD chamber from the outside world. A mechanical pump is then used to evacuate the MPCVD chamber for 30 minutes to simulate a vacuum state in the MPCVD chamber to prevent suspended matter and some gases in the air from affecting the growth process of polycrystalline diamonds and to ensure the quality of polycrystalline diamonds. The vacuum degree in the MPCVD chamber is controlled to be below 0.001 Torr, and the mechanical pump is stopped.

[0062] Then, ignition work is carried out: 300-500sccm of hydrogen is introduced into the MPCVD chamber to maintain the pressure in the MPCVD chamber at about 6Torr, and then the microwave power is turned on to preheat the power filament. After the preheating is completed, the microwave is turned on and the microwave power is set to 1000W;

[0063] Finally, the temperature is raised by adjusting the internal pressure of the MPCVD cavity and the microwave power. After the temperature in the MPCVD cavity reaches between 600-800°C, the temperature is raised. The thermal expansion gap between the molybdenum carrier 1 and the stainless steel ring 2 facilitates the assembly and disassembly of the molybdenum carrier 1 and the stainless steel ring 2. In this step, the molybdenum carrier 1 expands and fits tightly against the stainless steel ring 2, and the gap between the two is removed.

[0064] Step 5: Introduce deposition gas.

[0065] First, gas injection is performed, 10-50 sccm of methane is introduced into the MPCVD chamber, nitrogen is introduced into the MPCVD chamber, the nitrogen injection amount is controlled below 0.5 sccm, and 0.2-1 sccm of oxygen is introduced into the MPCVD chamber to complete the supply of polycrystalline diamond raw materials;

[0066] Subsequently, the deposition environment is controlled by fine-tuning the pressure in the MPCVD chamber to maintain it at 120-180Torr, fine-tuning the microwave power to maintain it at 7000-9000W, and fine-tuning the temperature in the MPCVD chamber to maintain it at 700-900℃. Changes in the polycrystalline diamond growth environment parameters caused by the injection of methane, nitrogen, and oxygen into the MPCVD chamber are eliminated to ensure the growth quality of polycrystalline diamond.

[0067] Step 6: Growth and deposition for a certain period of time. According to the preset target thickness of the polycrystalline diamond product, the MPCVD operation is controlled to maintain the deposition environment achieved in step 5 for a certain period of time. During this process, microwaves of a specific power form a strong electric field region above the substrate assembly, dissociating hydrogen and methane gases into atomic hydrogen and a series of carbon-containing precursor plasmas. The plasma is deposited onto the substrate assembly with a lower temperature below to form a diamond growth phenomenon. As time goes by, polycrystalline diamond is slowly deposited and grown on the substrate assembly.

[0068] In addition, the substrate assembly in the present application is composed of a molybdenum carrier plate 1 and a stainless steel ring 2 outside the molybdenum carrier plate 1. Due to the edge discharge phenomenon in the application of the microwave system, if the stainless steel ring 2 is not provided, a secondary plasma field will be generated at the edge of the molybdenum carrier plate 1. In this case, the resulting growth product will have a bulge at the very edge, and due to different temperatures and different thermal stresses, the grown product is easy to deform and break, which is also the main drawback of the application of microwave plasma chemical vapor deposition technology. In the present application, the stainless steel ring 2 will guide the secondary plasma field to the stainless steel. Since the deposition of diamond requires appropriate surface energy on the molybdenum carrier plate 1 to facilitate the adsorption, decomposition and deposition of carbon atoms, the surface energy of the stainless steel ring 2 is quite different from that of the diamond deposition material, resulting in the inability of carbon atoms to stably adhere, making the temperature field in the preset diamond deposition target area more uniform, solving the drawbacks of the microwave system in the polycrystalline diamond growth process, and improving the quality of polycrystalline diamonds generated by microwave plasma chemical vapor deposition technology;

[0069] Moreover, the stainless steel ring 2 has a large difference in lattice matching with the diamond, and a continuous and uniform crystal structure cannot be formed on the stainless steel ring 2, thereby preventing the growth of polycrystalline diamond on the side edge of the molybdenum carrier 1, resulting in the wafer being unable to be detached or the wafer being broken during the detachment process, thereby reducing the possibility of polycrystalline diamond grown on the molybdenum carrier 1 being broken during the removal stage;

[0070] Moreover, an oxide layer is easily formed on the surface of the stainless steel ring 2, and the oxide layer acts as a diaphragm to prevent carbon atoms from depositing on the surface of the stainless steel ring 2, and the possibility of product growth on the outside of the molybdenum carrier plate 1 is extremely small;

[0071] In summary, the stainless steel ring 2 is used as a traction ring in the MPCVD polycrystalline deposition process. A graphite-like amorphous carbon material will be formed on the surface of the stainless steel ring 2. This material will not adhere to the target polycrystalline diamond, thus solving the problem of cracks caused by side wall adhesion during diamond growth and detachment.

[0072] Step 7: Cool down the furnace, first stop the gas injection, and shut down the supply of methane, nitrogen, and oxygen in turn;

[0073] Then, the temperature is slowly lowered: the temperature reduction, pressure relief and microwave power reduction time are set to 300 minutes, so that the parameters such as air pressure, temperature and electric field around the polycrystalline diamond are slowly changed to avoid the thermal stress change of the material caused by rapid temperature reduction, which will cause the polycrystalline diamond to crack, reduce the occurrence of polycrystalline diamond slices formed on the molybdenum carrier 1, and effectively reduce the occurrence of cracks in the diamond slices;

[0074] Since the molybdenum carrier 1 is used as the growth platform of polycrystalline diamond, and there is a certain difference in the thermal expansion coefficients of molybdenum and diamond, which are the main constituent materials of the molybdenum carrier 1, as the temperature in the MPCVD chamber slowly decreases, the shrinkage degree of the surface of the molybdenum carrier 1 and the diamond slowly differs, and a stress difference is generated at the interface between the molybdenum carrier 1 and the polycrystalline diamond sheet. This stress difference will cause the bonding force between the two to weaken, and eventually the polycrystalline diamond sheet will be separated from the molybdenum carrier 1. No subsequent process is required to complete the separation of the molybdenum carrier 1 and the polycrystalline diamond sheet, which can shorten the polycrystalline diamond processing cycle, reduce time cost and material cost, and reduce the application of chemical materials to reduce environmental pollution caused by polycrystalline diamond processing.

[0075] Then the furnace is annealed. When the pressure in the MPCVD chamber reaches 3 Torr, the microwave power reaches 1000W, and the chip temperature is between 60-90 degrees, the microwave power is turned off.

[0076] Step 8: Polycrystalline diamond sheet separation:

[0077] First, cool down the wafer by turning off the hydrogen and waiting for 15 minutes.

[0078] Then, the exhaust work is carried out, and the mechanical pump is turned on to remove the residual reaction gas in the chamber, so that the pressure in the MPCVD chamber reaches 0.01Torr;

[0079] Then, the gas pressure control work is carried out: nitrogen is injected into the MPCVD chamber, the vacuum environment in the MPCVD chamber is removed, and the pressure in the MPCVD chamber reaches atmospheric pressure. Nitrogen is injected after the crystal diamond is formed to reduce the possibility of chemical reaction of the crystal diamond sheet;

[0080] Finally, the polycrystalline diamond is removed; the substrate assembly is withdrawn, the polycrystalline diamond is removed, and the substrate assembly is cleaned.

[0081] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for growing large-size polycrystalline diamond by heterogeneous growth, characterized in that: The steps include: Step 1: Ultrasonic cleaning of substrate assembly; Step 2: Purge and dry the substrate assembly with CDA; Step 3: Place the substrate assembly on the MPCVD water cooling table; Step 4: MPCVD equipment working; Step 5: introducing deposition gas; Step 6: Growth and deposition for a certain period of time; Step 7: Cool down and exit the furnace; Step 8: Polycrystalline diamond sheet separation; The substrate assembly comprises a molybdenum carrier plate (1) and a stainless steel ring (2) sleeved on the outer side of the molybdenum carrier plate (1).

2. The method for growing large-size heterogeneous polycrystalline diamond according to claim 1, characterized in that: The step 1 is specifically as follows: the molybdenum carrier plate (1) and the stainless steel ring (2) are placed in deionized water for ultrasonic cleaning for 30 minutes.

3. The method for growing large-size heterogeneous polycrystalline diamond according to claim 1, characterized in that: The second step is specifically as follows: placing the molybdenum carrier plate (1) and the stainless steel ring (2) in a CDA environment for blowing and drying to remove surface moisture.

4. The method for growing large-size heterogeneous polycrystalline diamond according to claim 1, characterized in that: The step three is specifically as follows: placing the molybdenum carrier (1) into the stainless steel ring (2), and placing the substrate assembly on the MPCVD carrier water cooling table.

5. The method for growing large-size heterogeneous polycrystalline diamond according to claim 1, characterized in that: The step 4 is specifically as follows: Preparation: Close the MPCVD chamber and use a mechanical pump to evacuate the MPCVD chamber for 30 minutes to make the vacuum degree in the MPCVD chamber reach below 0.001 Torr; Ignition: 300-500sccm hydrogen is introduced to maintain the pressure in the MPCVD chamber at about 6Torr, the microwave power is turned on, the power filament is preheated, and after the preheating is completed, the microwave is turned on and the microwave power is set to 1000W; Heating: Adjust the MPCVD cavity pressure and microwave power to make the temperature in the MPCVD cavity reach between 600-800°C to complete the heating.

6. The method for growing large-size heterogeneous polycrystalline diamond according to claim 1, characterized in that: The step five is as follows: Injection gas: 10-50sccm of methane is introduced into the MPCVD chamber, <0.5sccm of nitrogen is introduced into the MPCVD chamber, and 0.2-1sccm of oxygen is introduced into the MPCVD chamber; Deposition environment control: fine-tune the MPCVD chamber pressure to maintain it at 120-180 Torr, fine-tune the microwave power to maintain it at 7000-9000W, and fine-tune the MPCVD chamber temperature to maintain it at 700-900℃; The specific steps of step six are as follows: according to the target thickness of the polycrystalline diamond, the MPCVD operation is controlled to maintain the deposition environment achieved in step five for a certain period of time, and the polycrystalline diamond is slowly deposited and grown on the substrate combination.

7. The method for growing large-size heterogeneous polycrystalline diamond according to claim 1, characterized in that: The step seven is as follows: Gas injection stop: stop the supply of methane, nitrogen and oxygen; Slow cooling: Set the cooling, pressure relief and microwave power reduction time to 300 minutes. Slow cooling can effectively reduce the occurrence of cracks in the diamond sheet. Annealing: When the pressure in the MPCVD chamber reaches 3 Torr, the microwave power reaches 1000W, and the chip temperature is between 60-90 degrees, turn off the microwave power.

8. The method for growing large-size heterogeneous polycrystalline diamond according to claim 1, characterized in that: The step eight is specifically as follows: Cooling: Turn off the hydrogen and wait for the wafer to cool for 15 minutes; Exhaust: Turn on the mechanical pump to remove the residual reaction gas in the chamber, so that the pressure in the MPCVD chamber reaches 0.01Torr; Gas pressure control: nitrogen is injected into the MPCVD chamber to break the vacuum environment in the MPCVD chamber and make the pressure in the MPCVD chamber reach atmospheric pressure; Take out; withdraw the substrate assembly and take out the polycrystalline diamond.

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