Substrate table for microwave plasma chemical vapor deposition

Abstract

The utility model provides a substrate table for microwave plasma chemical vapor deposition, which is characterized in that the upper surface of an upper substrate is provided with a plurality of placing grooves, the bottom surface of the upper substrate opposite to the placing grooves is provided with a transfer groove, and vent holes are arranged between the side walls of the placing grooves and the transfer groove; the upper substrate is embedded in the lower substrate, and the transfer groove and the lower substrate form a transfer cavity; the lower substrate is provided with air inlet holes communicated with the transfer cavities. By arranging the air temperature control mechanism which directly sprays air to the bottom of the placing groove, the growth temperature of the diamond is effectively reduced, and after the middle rotating cavity is filled with gas, the temperature of the four side faces of the diamond substrate is controlled. According to the substrate table, cooling water circulation and air cooling are combined, and the gas flow at different positions of the substrate table can be controlled through control of a valve, so that precise temperature control is carried out on single crystal diamond seed crystals at each position, the growth temperature of each seed crystal is kept consistent, the whole growth process is higher in temperature, and the crystal quality is higher.

Description

Technical Field

[0001] The utility model belongs to the technical field of MPCVD equipment, and in particular relates to a substrate table for microwave plasma chemical vapor deposition. Background Art

[0002] When microwave plasma chemical vapor deposition (MPCVD) equipment is used to grow single crystal / polycrystalline diamond, due to the characteristics of microwave-excited plasma itself, which has high central energy and low edge energy, as well as the difference in thermal conductivity caused by the thickness and crystal quality of the single crystal diamond seed crystal, and the unevenness of the substrate quality during the growth of polycrystalline diamond, factors such as these will lead to large temperature differences at different positions on the substrate table. The temperature difference will lead to unstable quality of single crystal diamond products and increased internal stress of polycrystalline diamond. When the temperature difference increases, both single crystal diamond and polycrystalline diamond may develop cracks during the growth process.

[0003] The energy difference at different positions of the plasma itself is related to the excitation principle of microwaves in the cavity and is difficult to adjust. The quality control of single-crystal diamond seeds is difficult to adjust during batch growth, which affects the crystal quality. Utility Model Content

[0004] The utility model provides a substrate stage for microwave plasma chemical vapor deposition, which can effectively solve the above problems.

[0005] The utility model is achieved in this way:

[0006] A substrate stage for microwave plasma chemical vapor deposition comprises an upper substrate and a lower substrate, wherein the upper surface of the upper substrate is provided with a plurality of placement grooves, a transfer groove is provided on the bottom surface of the upper substrate opposite to the placement grooves, and air holes are provided between the side walls of the placement grooves and the transfer grooves; the upper substrate is embedded on the lower substrate, and the transfer grooves and the lower substrate form a transfer cavity; the lower substrate is provided with air inlets connected to the transfer cavities.

[0007] As a further improvement, the air inlet holes close to the air inlet of the transfer chamber are respectively opposite to the center of the placement groove.

[0008] As a further improvement, upper air outlet holes are provided around the placement groove, the height of the upper air outlet holes to the bottom surface of the placement groove is 0.5-2mm, and the lower end of the transfer groove is provided with a lower air outlet hole.

[0009] As a further improvement, the air outlet of the upper air outlet hole is retracted toward the inner wall of the placement groove by 0.3-1 mm.

[0010] As a further improvement, the air inlet holes are respectively connected to air inlet pipes, and the air inlet pipes are respectively provided with a flow meter and a pressure reducing valve.

[0011] As a further improvement, the lower base plate is provided with a circulating water cooling mechanism.

[0012] As a further improvement, the lower base plate is a "T"-shaped plate.

[0013] As a further improvement, the vertical plate of the "T"-shaped plate is provided with a plurality of vertical first air inlet holes, and the horizontal plate is provided with a plurality of second air inlet holes connecting the transfer cavity and the first air inlet holes.

[0014] As a further improvement, the second air inlet hole is provided with an air inlet groove and an air inlet pipe, the air inlet groove is connected to the transfer chamber of the first air inlet hole, the air inlet pipe is arranged in the first air inlet hole and the air inlet groove, and the outlet section of the air inlet pipe is perpendicular to the bottom surface of the transfer groove.

[0015] As a further improvement, the "T"-shaped plate is provided with a first T-plate and a second T-plate, a through hole is provided in the center of the second T-plate, the second T-plate and the transfer chamber are respectively provided with a third air inlet hole, the connecting surfaces of the first T-plate and the second T-plate are respectively provided with an arc groove connected to the third air inlet hole, the arc grooves of the first T-plate and the second T-plate constitute a fourth air inlet hole, and connecting pipes are provided in the third air inlet hole and the fourth air inlet hole.

[0016] As a further improvement, the second T-plate may also be funnel-shaped, and the corresponding through hole may also be funnel-shaped.

[0017] The beneficial effect of the utility model is that the application effectively reduces the growth temperature of diamond by setting an air temperature control mechanism that directly sprays air to the bottom of the diamond placement groove. When the transfer chamber is filled with gas, the gas will pass from the lower outlet at the bottom of the cavity through the vent to the upper outlet on the side of the placement groove, and the temperature of the four sides of the diamond substrate is controlled. The substrate table is a temperature control mechanism that combines cooling water circulation and air cooling, and the gas flow at different positions of the substrate table can be controlled by valve control, thereby accurately controlling the temperature of the single crystal diamond seed crystal at each position, ensuring that the growth temperature of each seed crystal remains consistent, making the entire growth process more stable and the crystal quality higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the implementation mode of the utility model, the drawings required for use in the implementation mode will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram provided by an embodiment of a substrate stage for microwave plasma chemical vapor deposition of the utility model;

[0020] Figure 2 yes Figure 1 The enlarged schematic diagram of point A in the middle;

[0021] Figure 3 It is a top view provided by an embodiment of a substrate stage for microwave plasma chemical vapor deposition of the utility model;

[0022] Figure 4 It is a bottom view provided by an embodiment of a substrate stage for microwave plasma chemical vapor deposition of the utility model;

[0023] Figure 5 It is an exploded view provided by another embodiment of a substrate station for microwave plasma chemical vapor deposition of the utility model;

[0024] Figure 6 It is a structural schematic diagram of another embodiment of a microwave plasma chemical vapor deposition substrate stage provided by the utility model;

[0025] Figure 7 It is an exploded view provided by an embodiment of a substrate stage for microwave plasma chemical vapor deposition of the utility model;

[0026] Figure 8 yes Figure 7 Bottom view of the second T-plate;

[0027] Fig. 9 yes Figure 7 A top view of the first T-plate;

[0028] Fig.10 It is a structural schematic diagram of another first T-plate and a second T-plate provided in an embodiment of a substrate stage for microwave plasma chemical vapor deposition of the utility model.

[0029] Reference numerals:

[0030] Upper base plate 1; lower base plate 2; placement groove 3; transfer groove 4; air vent 5; upper air outlet 51; lower air outlet 52; air outlet 53; air inlet 6; air inlet 60; air inlet pipe 61; flow meter 62; pressure reducing valve 63; first air inlet 64; second air inlet 65; air inlet groove 651; first T-plate 66; second T-plate 67; third air inlet 671; fourth air inlet 672; arc groove 673; through hole 68; circulating water cooling mechanism 7. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are 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. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the utility model for which protection is claimed, but merely represents selected embodiments of the utility model.

[0032] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0033] In the description of the present invention, the terms "upper surface", "relative", "side wall", "upper", "center", "bottom surface" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] Reference Figure 1-10 As shown, a substrate stage for microwave plasma chemical vapor deposition includes an upper substrate 1 and a lower substrate 2. The upper surface of the upper substrate 1 is provided with a plurality of placement grooves 3, and a transfer groove 4 is provided on the bottom surface of the upper substrate 1 opposite to the placement grooves 3. An air vent 5 is provided between the side walls of the placement grooves 3 and the transfer groove 4; the upper substrate 1 is embedded in the lower substrate 2, and the transfer groove 4 and the lower substrate 2 form a transfer cavity; the lower substrate 2 is provided with an air inlet 6 connected to each transfer cavity.

[0035] The structural design of the upper base plate 1 and the lower base plate 2 is advantageous for processing the transfer slot 4 and the internal holes.

[0036] The temperature-controlled air is transported to the transfer chamber from the air inlet 6 of the lower substrate 2, and the air is sprayed to the bottom surface of the transfer groove 4 and conducted to the bottom surface of the placement groove 3; after the transfer chamber is filled with gas, it is discharged from the vent 5 to further control the temperature around the diamond substrate in the placement groove 3.

[0037] Furthermore, the air inlet 60 of the air inlet hole 6 close to the transfer chamber is respectively opposite to the center of the placement groove 3.

[0038] The air inlet 60 is vertically opposite to the central bottom surface of the placement slot 3 .

[0039] The temperature in the center of slot 3 is the highest, and cold air is used for priority treatment to improve the temperature control effect.

[0040] Furthermore, upper air outlet holes 51 are provided around the placement groove 3 , and the height between the upper air outlet holes 51 and the bottom surface of the placement groove 3 is 0.5-2 mm. The lower end of the transfer groove 4 is provided with a lower air outlet hole 52 .

[0041] The height of the upper air outlet 51 cannot be set flush with the bottom surface, otherwise the gas will enter between the seed crystal and the bottom surface, causing the seed crystal to move during the growth process. The gas from the vent 5 is diffused from the transfer chamber. The gas uses hydrogen or argon, which will not affect the growth. The lower air outlet 52 is set at the lower end. On the one hand, the air is discharged after the transfer chamber is full, and on the other hand, it is convenient to process the vent 5.

[0042] Furthermore, the air outlet 53 of the upper air outlet 51 is retracted toward the inner wall of the placement groove 3 by 0.3-1 mm, preferably 0.5 mm.

[0043] In MPCVD, the plasma will generate energy concentration at the raised position. This concave structural design will cause the plasma energy entering this area to be very low. In addition, the seed crystal blocking on the outside will effectively protect this area from the influence of plasma.

[0044] Furthermore, the air inlet holes 6 are respectively connected to air inlet pipes 61 , and the air inlet pipes 61 are respectively provided with a flow meter 62 and a pressure reducing valve 63 .

[0045] Furthermore, the lower base plate 2 is provided with a circulating water cooling mechanism 7 .

[0046] Furthermore, the lower base plate 2 is a "T"-shaped plate.

[0047] Furthermore, a plurality of vertical first air inlet holes 64 are provided on the vertical plate of the “T”-shaped plate, and a plurality of second air inlet holes 65 communicating with the transfer cavity and the first air inlet holes 64 are provided on the horizontal plate.

[0048] Furthermore, the second air inlet hole 65 is provided with an air inlet groove 651 and an air inlet pipe, the air inlet groove 651 is connected to the transfer cavity of the first air inlet hole 64, the air inlet pipe is arranged in the first air inlet hole 64 and the air inlet groove 651, and the outlet section of the air inlet pipe is perpendicular to the bottom surface of the transfer groove 4.

[0049] Since the second air inlet hole 65 located in the center corresponds to the placement groove 3 located in the center, there is no need to set the air inlet groove 651. The second air inlet hole 65 can be directly processed.

[0050] For the convenience of processing, an air inlet groove 651 is adopted to avoid air leakage and an air inlet pipe is arranged in the air inlet groove 651 .

[0051] Furthermore, the "T"-shaped plate is provided with a first T-plate 66 and a second T-plate 67, a through hole 68 is provided in the center of the second T-plate 67, the second T-plate 67 and the transfer chamber are respectively provided with a third air inlet hole 671 corresponding to each other, the connecting surfaces of the first T-plate 66 and the second T-plate 67 are respectively provided with an arc groove 673 connected to the third air inlet hole 671, the arc grooves 673 of the first T-plate 66 and the second T-plate 67 constitute a fourth air inlet hole 672, and connecting pipes are provided in the third air inlet hole 671 and the fourth air inlet hole 672.

[0052] The arc groove 673 is a semicircular groove, and the two arc grooves form the fourth air inlet 672. The connecting pipe prevents leakage of gas delivery and is conducive to control.

[0053] Since the fourth air inlet hole 672 located in the center corresponds to the placement groove 3 located in the center, there is no need to set the arc groove 673. The fourth air inlet hole 672 can be directly set by machining the hole.

[0054] The second T-plate 67 may also be funnel-shaped, and the corresponding through hole 68 may also be funnel-shaped.

[0055] The placement slots 3 can be square or round, and the substrate table can be square or round. The placement slots 3 are evenly arranged on the upper substrate 1, and as many as possible are arranged to improve production efficiency. This application takes 5 placement slots 3 as an example, which can accommodate 5 15mm*15mm single crystal / polycrystalline diamond substrates or multiple smaller substrates; the position of the upper air outlet 51 is not in the same plane as the protrusions around the placement slot 3, but is slightly indented inward by 0.5mm, so as to avoid direct contact with the plasma and cause diamond deposition at the orifice and blockage;

[0056] The gas transfer slot 4 at the bottom of the diamond placement slot 3, each placement slot 3 has a gas transfer slot 4 at the bottom, a total of 5, each transfer slot 4 is inflated by an independent pipeline 5, because the air passes through the water cooling mechanism, the gas temperature entering the transfer chamber through the air inlet 6 or the pipeline is relatively low, when it is directly sprayed to the bottom of the diamond placement slot 3, it will effectively reduce the growth temperature of the diamond. When the transfer chamber is filled with gas, the gas will pass from the vent hole 5 at the bottom of the cavity to the outlet hole 51 on the side of the placement slot 3, and the temperature of the four sides of the diamond substrate is controlled.

[0057] The upper substrate 1 and the lower substrate 2 of the substrate stage are made of metal molybdenum, which is relatively easy to process precisely because of its high toughness, good heat dissipation, and no reaction with the process gas used for diamond. The upper substrate 1 and the lower substrate 2 are embedded through a special design (the embedded design reduces the plasma from entering between the two special substrates, and the surface smoothness and parallelism indicators are high, with a surface roughness of less than 1nm and a parallelism of less than 0.01.

[0058] The gas inlet 6 is connected to the gas flow meter 62 and the gas valve, with a total of 5 pipelines, which are respectively connected to 5 gas transfer chambers; the gas flow meter 62 can adjust the flow of the corresponding gas according to the different temperature control requirements of the diamond placement groove 3 during the growth process, and then control the temperature; the gas valve is a gas pressure reducing valve 63, which controls the intake pressure of each pipeline.

[0059] The water cooling channel of the circulating water cooling mechanism 7 of the entire substrate stage is made of brass or copper and contacts the bottom surface of the lower part of the special substrate stage to cool the special substrate stage by cooling water.

[0060] The above description is only the preferred implementation of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A substrate stage for microwave plasma chemical vapor deposition, characterized in that: It includes an upper base plate and a lower base plate, wherein the upper surface of the upper base plate is provided with a plurality of placement grooves, a transfer groove is provided on the bottom surface of the upper base plate opposite to the placement grooves, and an air vent is provided between the side walls of the placement grooves and the transfer groove; the upper base plate is embedded on the lower base plate, and the transfer groove and the lower base plate form a transfer cavity; the lower base plate is provided with an air inlet hole connected to each transfer cavity.

2. The substrate stage according to claim 1, wherein: The air inlet holes close to the air inlet of the transfer chamber are respectively opposite to the center of the placement groove.

3. The substrate stage according to claim 1 or 2, characterized in that: Upper air outlet holes are arranged around the placement groove, and the height between the upper air outlet holes and the bottom surface of the placement groove is 0.5-2mm. The lower end of the transfer groove is provided with a lower air outlet hole.

4. The substrate stage according to claim 3, wherein: The air outlet of the upper air outlet hole is retracted 0.3-1 mm toward the inner wall of the placement groove.

5. The substrate stage according to claim 1, wherein: The air inlet holes are respectively connected to air inlet pipes, and the air inlet pipes are respectively provided with flow meters and pressure reducing valves.

6. The substrate stage according to claim 1, wherein: The lower base plate is provided with a circulating water cooling mechanism.

7. The substrate stage according to claim 1, wherein: The lower base plate is a "T"-shaped plate.

8. The substrate stage according to claim 7, wherein: The vertical plate of the "T"-shaped plate is provided with a plurality of vertical first air inlet holes, and the horizontal plate is provided with a plurality of second air inlet holes communicating with the transfer cavity and the first air inlet holes.

9. The substrate stage according to claim 8, characterized in that: The second air inlet hole is provided with an air inlet groove and an air inlet pipe, the air inlet groove is connected to the transfer chamber of the first air inlet hole, the air inlet pipe is arranged in the first air inlet hole and the air inlet groove, and the outlet section of the air inlet pipe is perpendicular to the bottom surface of the transfer groove.

10. The substrate stage according to claim 7, wherein: The "T"-shaped plate is provided with a first T-plate and a second T-plate, a through hole is provided in the center of the second T-plate, the second T-plate and the transfer chamber are respectively provided with a third air inlet hole, the connecting surfaces of the first T-plate and the second T-plate are respectively provided with an arc groove connected to the third air inlet hole, the arc grooves of the first T-plate and the second T-plate constitute a fourth air inlet hole, and connecting pipes are provided in the third air inlet hole and the fourth air inlet hole.

Images