阅读说明：本技术 金刚石圆片径向生长方法及装置 (Radial growth method and device for diamond wafer ) 是由 王忠强 陶仁春 王�琦 张国义 王新强 于 2021-08-05 设计创作，主要内容包括：本发明涉及晶体合成技术领域,尤指一种金刚石圆片径向生长方法及装置,该包括升降式旋转支架和晶圆夹持单元；升降式旋转支架包括升降杆装置、横架、距离调整组件、旋转驱动组件和至少两组平行设置的旋转轴；而该生长方法通过晶圆夹持单元将多片金刚石圆片同轴夹持成柱状,然后安置在升降式旋转支架,升降式旋转支架带动金刚石圆片转动、升降及间隙控制作用下,金刚石圆片侧面暴露在工艺气体激发后的等离子体中,使得金刚石圆片只沿着侧面径向旋转生长,从而生长出大直径金刚石圆片,通过晶圆夹持单元保持金刚石圆片的厚度,通过旋转轴的研磨保持金刚石圆片的圆度。(The invention relates to the technical field of crystal synthesis, in particular to a radial growth method and a radial growth device for a diamond wafer, which comprise a lifting type rotating bracket and a wafer clamping unit; the lifting type rotating support comprises a lifting rod device, a cross frame, a distance adjusting assembly, a rotating driving assembly and at least two groups of rotating shafts which are arranged in parallel; according to the growth method, a plurality of diamond wafers are coaxially clamped into a columnar shape through a wafer clamping unit and then are arranged on a lifting type rotating support, the lifting type rotating support drives the diamond wafers to rotate, lift and play, under the action of gap control, the side faces of the diamond wafers are exposed in plasma excited by process gas, the diamond wafers only radially rotate and grow along the side faces, and therefore the large-diameter diamond wafers grow, the thickness of the diamond wafers is kept through the wafer clamping unit, and the roundness of the diamond wafers is kept through grinding of a rotating shaft.)

1. A radial growth method of a diamond wafer is characterized by comprising the following steps:

clamping a diamond wafer on a wafer clamping unit;

placing the wafer clamping unit clamped with the diamond wafer on a rotating shaft of the rotating bracket, so that the axis of the wafer clamping unit is parallel to the axis of the rotating shaft;

thirdly, the rotary driving assembly drives the rotary shaft to rotate, and the diamond wafer is driven to rotate reversely by the friction force between the rotary shaft and the side face of the diamond wafer;

starting a chemical vapor deposition process to allow the diamond wafer to grow in a proper process atmosphere;

fifthly, adjusting the rotating speed, the height and the distance of the rotating shaft according to the growth state of the diamond wafer, so that the diamond wafer grows in a set process atmosphere;

and step five is continuously circulated, and the growth process is stopped when the diamond wafer grows to the set diameter.

2. A radial growth device of diamond disk, its characterized in that: the device comprises a lifting type rotating support and a wafer clamping unit; the lifting type rotating support comprises a lifting rod device, a cross frame, a distance adjusting assembly, a rotating driving assembly and at least two groups of rotating shafts arranged in parallel; the cross frame is arranged at the top of the lifting rod device; the distance adjusting assembly is arranged on the transverse frame and used for adjusting the distance between two adjacent wafer clamping units; the rotary driving assembly is arranged on the distance adjusting assembly and is in driving connection with the rotary shaft; the wafer clamping unit is used for coaxially clamping a plurality of diamond wafers into a cylindrical shape and is placed between the two rotating shafts.

3. A diamond wafer radial growth device as in claim 2, wherein: and a water cooling jacket is arranged in the rotating shaft.

4. A diamond wafer radial growth device as in claim 2, wherein: the distance adjusting assembly is an electric adjusting assembly, and the electric adjusting assembly comprises a guide rail arranged on the cross frame, a plurality of sliding blocks arranged on the guide rail, a transmission rod and a stepping motor; one end of the transmission rod is connected with the sliding block, and the other end of the transmission rod is connected with an output shaft of the stepping motor; the rotary drive assembly is mounted on the slide.

5. A diamond wafer radial growth device as in claim 2, wherein: the distance adjusting assembly is a manual adjusting assembly, the manual adjusting assembly comprises an installation seat and a locking nut, the rotary driving assembly is installed on the installation seat, and a threaded column is arranged on one surface of the installation seat, which is back to the rotary driving assembly; the crossbearer is provided with a strip-shaped hole along the extension direction of the crossbearer, the threaded column penetrates through the strip-shaped hole and is screwed up and fixed through the locking nut.

6. A diamond wafer radial growth device as in any one of claims 2 to 5, wherein: the wafer clamping unit comprises a bolt and a nut, the bolt coaxially penetrates a plurality of diamond wafers, and the diamond wafers are clamped and locked through the nut; the bolt with the diamond disk is placed between the two rotating shafts and is arranged coaxially with the rotating shafts.

7. A diamond wafer radial growth device as in claim 6, wherein: the wafer clamping unit further comprises a spring, and the spring and the diamond wafer penetrate through the bolt and are clamped and locked through a nut.

8. A diamond wafer radial growth device as in any one of claims 2 to 5, wherein: the wafer clamping unit comprises a bolt, a U-shaped clamping arm and a chuck for coaxially overlapping and clamping a plurality of diamond wafers, two ends of the chuck are respectively connected with two sides of an opening at the upper end of the U-shaped clamping arm, and the U-shaped clamping arm is in threaded connection with the bolt; the chuck containing the diamond disk is placed between the two rotating shafts and is arranged coaxially with the rotating shafts.

9. A diamond wafer radial growth device as in claim 8, wherein: the U-shaped support arm comprises a first support arm and a second support arm, a limiting column is arranged at the lower end of the first support arm, a limiting hole for the limiting column to insert is formed in the lower end of the second support arm, and the bolt extends into the limiting hole and is in threaded connection with the limiting column.

10. A diamond wafer radial growth device as in claim 9, wherein: the wafer clamping unit further comprises a spring, the spring and the diamond wafer penetrate through the bolt and are clamped and locked through a nut, and the spring penetrates through the bolt and abuts against the second support arm.

Technical Field

The invention relates to the technical field of crystal synthesis, in particular to a radial growth method and a radial growth device for a diamond wafer.

Background

The single crystal diamond has excellent physical and chemical properties, and especially has important application value in the fields of optical windows, heat dissipation, electronic devices and the like. To expand these applications, large area diamond wafers need to be prepared.

Among various diamond preparation methods, the microwave plasma chemical vapor deposition method is the preferred method for preparing high-quality diamond due to the characteristics of high plasma power density, no electrode discharge pollution, stable performance and the like. In the process of producing large-area single crystal diamond by the current method, diamond seed crystals are generally fixed on a deposition table, mosaic splicing is adopted, the temperature of the seed crystals is controlled by cooling the deposition table, unidirectional growth is carried out on the side of the seed crystals facing to plasma, and then the single crystals are peeled layer by adopting ion implantation. Because mosaic splicing needs to select seed crystals with the same crystal orientation, splicing difficulty is high, the seed crystals need to be copied after growth and stripped by adopting ion implantation, equipment is expensive, and stripping difficulty is high.

The prior art also discloses a preparation method of a large-diameter diamond sheet, but the method has difficulty in controlling the roundness and the thickness of a wafer in the continuous long-period growth process.

Disclosure of Invention

In order to solve the problems, the invention provides a radial growth method and a radial growth device for a diamond wafer, which can directly grow a large-diameter diamond wafer and can well keep the roundness and the thickness of the diamond wafer in the long-period growth process.

In order to achieve the purpose, the invention adopts the technical scheme that a radial growth method of a diamond wafer is provided, and comprises the following steps:

clamping a diamond wafer on a wafer clamping unit;

placing the wafer clamping unit clamped with the diamond wafer on a rotating shaft of the rotating bracket, so that the axis of the wafer clamping unit is parallel to the axis of the rotating shaft;

thirdly, the rotary driving assembly drives the rotary shaft to rotate, and the diamond wafer is driven to rotate reversely by the friction force between the rotary shaft and the side face of the diamond wafer;

starting a chemical vapor deposition process to allow the diamond wafer to grow in a proper process atmosphere;

fifthly, adjusting the rotating speed, the height and the distance of the rotating shaft according to the growth state of the diamond wafer, so that the diamond wafer grows in a set process atmosphere;

and step five is continuously circulated, and the growth process is stopped when the diamond wafer grows to the set diameter.

In order to obtain the preparation method, the invention also provides a radial growth device for the diamond wafer, which comprises a lifting type rotating support and a wafer clamping unit; the lifting type rotating support comprises a lifting rod device, a cross frame, a distance adjusting assembly, a rotating driving assembly and at least two groups of rotating shafts arranged in parallel; the cross frame is arranged at the top of the lifting rod device; the distance adjusting assembly is arranged on the transverse frame and used for adjusting the distance between two adjacent wafer clamping units; the rotary driving assembly is arranged on the distance adjusting assembly and is in driving connection with the rotary shaft; the wafer clamping unit is used for coaxially clamping a plurality of diamond wafers into a cylindrical shape and is placed between the two rotating shafts.

Preferably, a water cooling jacket is arranged inside the rotating shaft.

As a preferred scheme, the distance adjusting assembly is an electric adjusting assembly, and the electric adjusting assembly comprises a guide rail arranged on the cross frame, a plurality of sliding blocks arranged on the guide rail, a transmission rod and a stepping motor; one end of the transmission rod is connected with the sliding block, and the other end of the transmission rod is connected with an output shaft of the stepping motor; the rotary drive assembly is mounted on the slide.

As a preferable scheme, the distance adjusting assembly is a manual adjusting assembly, the manual adjusting assembly comprises an installation seat and a locking nut, the rotary driving assembly is installed on the installation seat, and a threaded column is arranged on one surface of the installation seat, which faces away from the rotary driving assembly; the crossbearer is provided with a strip-shaped hole along the extension direction of the crossbearer, the threaded column penetrates through the strip-shaped hole and is screwed up and fixed through the locking nut.

As a preferable scheme, the wafer clamping unit comprises a bolt and a nut, the bolt coaxially penetrates through a plurality of diamond wafers, and the diamond wafers are clamped and locked through the nut; the bolt with the diamond disk is placed between the two rotating shafts and is arranged coaxially with the rotating shafts.

As a preferable scheme, the wafer clamping unit further comprises a spring, and the spring and the diamond wafer are arranged in the bolt in a penetrating mode and clamped and locked through a nut.

As a preferred scheme, the wafer clamping unit comprises a bolt, a U-shaped clamping arm and a chuck for coaxially overlapping and clamping a plurality of diamond wafers, wherein two ends of the chuck are respectively connected with two sides of an opening at the upper end of the U-shaped clamping arm, and the U-shaped clamping arm is in threaded connection with the bolt; the chuck containing the diamond disk is placed between the two rotating shafts and is arranged coaxially with the rotating shafts.

As a preferred scheme, the U-shaped support arm includes a first support arm and a second support arm, the lower end of the first support arm is provided with a limiting column, the lower end of the second support arm is provided with a limiting hole for the limiting column to be inserted into, and the bolt extends into the limiting hole and is in threaded connection with the limiting column.

As a preferable scheme, the wafer clamping unit further comprises a spring, the spring and the diamond wafer are arranged in the bolt in a penetrating mode and clamped and locked through a nut, and the spring is arranged in the bolt in a penetrating mode and abuts against the second support arm.

The invention has the beneficial effects that:

1. compared with the prior art, the preparation method of the invention can directly grow the large-diameter monocrystal diamond wafer without precise and complicated splicing, cutting and stripping technologies and on-line mask coating technologies;

2. the process equipment is simple, the industrial preparation production is met, and in the process of preparing the large-diameter diamond wafer, after a plurality of diamond wafers are overlapped and clamped, the side surfaces of the diamond wafers are exposed in the chemical vapor deposition process atmosphere, wherein the outer two wafers are used as auxiliary wafers for protecting the bottom surfaces of the diamond wafers clamped in the middle, so that the diamond wafer in the middle is epitaxially grown only on the side surfaces;

3. under the rotating, lifting and gap control effects of the lifting type rotating support, the diamond wafer can obtain equal growth opportunities in the circumferential direction of the side surface, and the bottom surface is shielded by the adjacent diamond wafer and has no growth opportunities, so that the diamond wafer is only grown on the side surface to enable the diameter to be continuously increased, and the bottom surface is not grown to keep the thickness unchanged; the friction drive of the rotating shaft on the lifting type rotating support plays a role of cylindrical grinding, so that the side face of the diamond wafer keeps smooth in the growth process. In the growth process of a long period, the purpose of controlling the diameter and the thickness is achieved by grinding the side surface of the rotating shaft and shielding the bottom surface of the adjacent diamond wafer;

4. in addition, a plurality of rotating shafts and a plurality of wafer clamping units can be arranged at the same time, and a plurality of diamond wafers can be clamped for batch growth.

Drawings

Fig. 1 is a schematic structural view of a first embodiment of the diamond wafer radial growth apparatus of the present invention.

Fig. 2 is a schematic structural diagram of the wafer clamping unit in fig. 1.

Fig. 3 is a schematic view of the diamond wafer of fig. 1 after a period of growth.

Fig. 4 is a schematic structural diagram of the wafer clamping unit in fig. 3.

Fig. 5 is a schematic structural view of a second embodiment of the diamond wafer radial growth apparatus of the present invention.

Fig. 6 is a schematic structural diagram of the wafer clamping unit in fig. 5.

The reference numbers illustrate: 10. 10 a-lifting type rotating support; 11. 11 a-a lifter device; 12. 12 a-a cross-frame; 13. 13 a-axis of rotation; 20. 20 a-a wafer holding unit; 21. 21 a-bolt; 22-a nut; 23. 23 a-a spring; 24-a chuck; 25-a first support arm; 26-a second support arm; 27-a limiting column; 28-a bearing seat; 30. 30 a-a diamond disk; 40-region of overlap.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are used broadly and can be, for example, a fixed connection, a detachable connection, an integrated connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, or a communication between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The invention relates to a radial growth method of a diamond wafer, which comprises the following steps:

clamping a diamond wafer on a wafer clamping unit;

placing the wafer clamping unit clamped with the diamond wafer on a rotating shaft of the rotating bracket, so that the axis of the wafer clamping unit is parallel to the axis of the rotating shaft;

thirdly, the rotary driving assembly drives the rotary shaft to rotate, and the diamond wafer is driven to rotate reversely by the friction force between the rotary shaft and the side face of the diamond wafer;

starting a chemical vapor deposition process to allow the diamond wafer to grow in a proper process atmosphere;

fifthly, adjusting the rotating speed, the height and the distance of the rotating shaft according to the growth state of the diamond wafer, so that the diamond wafer grows in a set process atmosphere;

and step five is continuously circulated, and the growth process is stopped when the diamond wafer grows to the set diameter.

Compared with the prior art, the preparation method of the invention can directly grow the large-diameter diamond wafer without precise and complicated splicing, cutting and stripping technologies and on-line mask coating technologies; the process equipment is simple, the industrial preparation production is met, and in the process of preparing the large-diameter diamond wafer, after a plurality of diamond wafers are overlapped and clamped, the side surfaces of the diamond wafers are exposed in the chemical vapor deposition process atmosphere, meanwhile, the diamond wafers can obtain equal growth opportunities in the circumferential direction of the side surfaces under the rotating, lifting and gap control effects of the lifting type rotating support, the bottom surfaces of the diamond wafers are shielded by adjacent diamond wafers, the growth opportunities are avoided, the diamond wafers can grow only on the side surfaces, the diameter of the diamond wafers can be continuously increased, and the thickness of the diamond wafers can be kept unchanged without growing on the bottom surfaces. In the growth process of a long period, the diameter and the thickness of the diamond wafer can be controlled by grinding the side surface of the rotating shaft and shielding the bottom surface of the adjacent diamond wafer.

In the second step, the diamond discs on two adjacent wafer clamping units are overlapped and clamped in a staggered manner. During chemical vapor deposition, the peripheral deposition speed of the wafer is the fastest, and the deposition is slower in the direction towards the center of the circle and basically no longer deposited when reaching a certain depth. Therefore, the overlapping size is controlled to just cover the deposition growth area, and the rest non-overlapping area can not be deposited and grown. In addition, if the deposition growth area is deep to the gap piece of the wafer, the bottom surfaces of the two wafers can be completely overlapped. The non-overlapped bare floor area is allowed to approach zero.

The preparation method of the invention is not only suitable for the process of growing diamond by Microwave Plasma Chemical Vapor Deposition (MPCVD), but also suitable for various processes of growing diamond by Chemical Vapor Deposition (CVD) such as a combustion flame method, a hot wire CVD method, a radio frequency plasma CVD method and the like.

Referring to fig. 1 to 4, a first embodiment of a radial diamond wafer growing apparatus according to the present invention is shown, the radial diamond wafer growing apparatus includes an elevating rotary stand 10 and a wafer clamping unit 20, the elevating rotary stand 10 includes an elevating rod device 11 and at least two sets of rotating shafts 13 arranged in parallel, the rotating shafts 13 are installed at the top end of the elevating rod device 11; the wafer clamping unit 20 is used for coaxially clamping a plurality of diamond wafers 30 into a cylindrical shape, and the wafer clamping unit 20 is placed between the two rotating shafts 13.

The device clamps a plurality of diamond wafers 30 through the wafer clamping unit 20, wherein the outer two diamond wafers are used as auxiliary wafers for protecting the bottom surfaces of the diamond wafers 30 clamped in the middle, so that the diamond wafers 30 in the middle are epitaxially grown only on the side surfaces; and the friction drive of the rotating shaft 13 on the lifting type rotating support 10 is matched to play a role of cylindrical grinding, so that the side surface of the diamond wafer 30 keeps smooth in the growth process. The number of the wafer clamping units 20 is one set less than the number of the rotation shafts 13, in this embodiment, three sets of the rotation shafts 13 are provided, and two sets of the wafer clamping units 20 are provided, but it is needless to say that a plurality of rotation shafts 13 and a plurality of wafer clamping units 20 may be provided at the same time to clamp a plurality of diamond wafers 30 for batch growth.

The lifting type rotating support 10 further comprises a cross frame 12, a rotating driving assembly and a distance adjusting assembly, wherein the rotating driving assembly and the distance adjusting assembly are installed on the cross frame 12, the cross frame 12 is vertically installed at the top end of the lifting rod device 11, and the distance adjusting assembly is installed on the cross frame 12 and can move on the cross frame 12; the rotary driving component is arranged on the distance adjusting component; the rotating shaft 13 and the rotating driving assembly are arranged on the distance adjusting assembly, and the rotating driving assembly is in driving connection with the rotating shaft 13. The rotation of the rotary shaft 13 is independently controlled; the rotating shaft 13 is driven to rotate by the rotating driving component, and the diamond wafer 30 is driven to rotate reversely by the rotation of the rotating shaft 13, so that the side surface of the diamond wafer 30 is uniformly subjected to chemical vapor deposition.

The distance adjusting assembly can adjust the distance between the rotating shafts 13, and adjust the distance between the adjacent rotating shafts 13 to adjust the distance between the diamond disks 30 in the adjacent wafer clamping units 20 when the diameter of the diamond disks 30 grows gradually, so as to optimize the overlapping area between the bottom surfaces of the diamond disks 30.

The lifting rod device 11 adopts an electric lifting rod, and when the diameter of the diamond wafer 30 grows gradually, the position of the diamond wafer 30 in the chemical vapor deposition chamber can be adjusted by reducing the height of the lifting rod device 11 so as to grow a product with better quality.

The rotating shaft 13 is made of one or a combination of molybdenum, tungsten and ceramic, a water cooling jacket (not shown) is arranged inside the rotating shaft 13, and the temperature of the diamond wafer 30 is regulated and controlled by regulating and controlling the temperature or flow of cooling water in the water cooling jacket, so that a product with better quality can be grown.

In this embodiment, the distance adjusting assembly is an electric adjusting assembly, and the electric adjusting assembly includes a guide rail mounted on the cross frame 12, a plurality of sliders mounted on the guide rail, a transmission rod, and a stepping motor; one end of the transmission rod is connected with the sliding block, and the other end of the transmission rod is connected with an output shaft of the stepping motor; the rotary driving component is arranged on the sliding block. The distance between the rotating shafts 13 can be adjusted through manual or automatic control, for example, an electric adjusting assembly is adopted, and the distance between the rotating shafts 13 is adjusted through a lead screw controlled by a stepping motor; since the structure is common in the mechanical field, the structure is not described in detail herein with reference to the drawings.

As shown in fig. 2, the wafer clamping unit 20 includes a bolt 21, a nut 22 and a spring 23, the bolt 21 coaxially penetrates a plurality of diamond disks 30, and finally the spring 23 is sleeved in the bolt, and the diamond disks 30 are clamped and locked by the nut 22, so that the diamond disks 30 are clamped and fixed; the bolt 21 provided with the diamond disk 30 is arranged between the two rotating shafts 13 and is coaxial with the rotating shafts 13; further, the size of the gap between the adjacent rotating shafts 13 is smaller than the diameter of the diamond wafer 30, the wafer clamping unit 20 is supported by the two adjacent rotating shafts 13 without falling off, and the rotation of the rotating shafts 13 of the wafer clamping unit 20 drives the diamond wafer 30 to rotate reversely by using the principle of the sausage roasting machine, so that the side surface of the diamond wafer 30 is uniformly subjected to chemical vapor deposition.

When the wafer holding unit 20 is heated from room temperature to the cvd growth temperature, the difference in expansion size is caused by the difference in expansion coefficient between the diamond wafer 30 itself and the nut 22, and the spring 23 is used to compensate the difference in expansion deformation size and provide a stable pressure, so that the diamond wafer 30 can maintain good contact in a large temperature range.

In this embodiment, the diamond disk 30 is a ring structure, and a plurality of diamond disks 30 can be strung together by bolts 21.

As shown in fig. 3 and 4, the diamond disks 30 on two adjacent wafer clamping units 20 are clamped in an overlapping and staggered manner, and the overlapping portion of the diamond disks 30 is an overlapping area 40. During chemical vapor deposition, the peripheral deposition speed of the diamond wafer 30 is the fastest, and the deposition is slower in the direction towards the center of the circle, so that the deposition is basically not carried out any more when the deposition reaches a certain depth. It is only necessary to control the area of the overlap region 40 to cover the deposition growth region, and the remaining non-overlap region will not be deposited. In addition, if the deposition growth zone is deep at the interstitial site of the diamond disks 30, the bottom surfaces of the two diamond disks 30 may also be made to completely overlap. The non-overlapped bare floor area is allowed to approach zero.

Referring to fig. 5 and 6, a second embodiment of the radial diamond wafer growing device according to the present invention is shown, the radial diamond wafer growing device includes a lifting/lowering rotating frame 10a and a wafer clamping unit 20a, the lifting/lowering rotating frame 10a includes a lifting/lowering rod device 11a, a cross frame 12a vertically installed on the top end of the lifting/lowering rod device 11a, and three sets of rotating shafts 13a arranged in parallel, the rotating shafts 13a are rotatably connected to the cross frame 12a and uniformly arranged along the extending direction of the cross frame 12 a; the wafer holding unit 20a is for coaxially holding a plurality of diamond wafers 30a in a cylindrical shape, and the wafer holding unit 20a is placed between the two rotation shafts 13 a.

The present embodiment has a lifting type rotation support 10a with the same structure as the first embodiment, and therefore the structure is not described herein again, which is different from the first embodiment in that: a wafer holding unit 20 a.

As shown in fig. 6, the wafer clamping unit 20a comprises a bolt 21a, a U-shaped clamping arm, a spring 23a and a chuck 24 for coaxially clamping a plurality of diamond disks 30a in an overlapping manner; the U-shaped supporting arm comprises a first supporting arm 25 and a second supporting arm 26, bearing seats 28 are arranged at the upper end of the first supporting arm 25 and the upper end of the second supporting arm 26, one end of the chuck 24 is connected with the bearing seats 28 in an installing mode, and the other end of the chuck is attached to a diamond wafer 30; the lower end of the first support arm 25 is provided with a limit post 27, and the lower end of the second support arm 26 is provided with a limit hole for inserting the limit post 27; the middle part of the limiting column 27 is provided with a thread groove, the bolt 21a is sleeved in the spring 23a and then extends into the limiting hole to be in threaded connection with the thread groove of the limiting column 27, and the spring 23a is abutted against the second support arm 26; the cartridge 24 containing the diamond wafer 30 is placed between the two rotary shafts 13a and is arranged coaxially with the rotary shafts 13a, the diamond wafer 30a allows the wafer holding unit 20a to be supported by the adjacent two rotary shafts 13a without dropping, and a U-shaped support arm is naturally provided vertically between the two rotary shafts 13 a.

In this embodiment, the diamond wafer 30a is a non-porous structure, and a plurality of diamond wafers 30a may be held by the chuck 24.

When the wafer chuck unit 20a is heated from room temperature to the cvd growth temperature, the difference in expansion size is caused by the difference in expansion coefficient between the diamond wafer 30a itself and the chuck 24, and the spring 23a is used to compensate the difference in expansion deformation size and provide a stable pressure, so that the diamond wafer 30a can maintain good contact in a large temperature range.

The above embodiments are merely illustrative of the preferred embodiments of the present invention, and not restrictive, and various changes and modifications to the technical solutions of the present invention may be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are intended to fall within the scope of the present invention defined by the appended claims.