Positioning device and positioning method of substrate support in MPCVD equipment

Abstract

The present invention proposes a positioning device and positioning method for a substrate holder in an MPCVD device, the device comprising: a fixed holder, used to position the substrate holder, which is a circular ring structure, whose inner circular ring surface is nested on the outer circular ring surface of the base, and the substrate holder is located in the hollow area of ​​the fixed holder; at least three positioning units, distributed along the circumference of the fixed holder, the movable end of each positioning unit can move along the radial direction of the fixed holder, and each movable end is higher than the base; when each movable end is circumscribed with the outer circular ring surface of the substrate holder, the positioning of the substrate holder is achieved. In the present invention, the end faces of the positioning unit and the substrate holder that are tangent to each other are freely fitted, and there is no problem of interference fit or too large or too small fit clearance; and the position of the substrate holder relative to the center of the base can be adjusted, that is, the eccentricity of the substrate holder can be adjusted to adapt to the eccentricity of the plasma sphere.

Description

Technical Field

[0001] The present invention belongs to the technical field of MPCVD equipment, and in particular relates to a positioning device and a positioning method for a substrate support in an MPCVD equipment. Background Art

[0002] One of the most commonly used methods for synthesizing diamonds is to deposit diamonds using microwave plasma (ultra-high frequency plasma). This microwave-excited plasma is clean and does not contain electrode sputtering, so the impurity content in the grown diamond is low, and diamonds with excellent optical and even electronic properties, as well as high-purity polycrystalline diamonds, can be obtained. In the MPCVD equipment, a substrate holder is placed on the base, and a single crystal seed wafer or a polycrystalline growth substrate is placed on the substrate holder. Under ideal conditions, the plasma is directly above the substrate holder. During the growth process, due to deviations in the mechanical structure of the MPCVD equipment or inaccurate placement of the substrate holder, the position of the plasma is not directly above the substrate holder. The temperature difference of the plasma from the center to the edge is large, so the temperature of the single crystal seed wafer or the polycrystalline growth substrate placed on the substrate holder is uneven, which in turn affects the growth quality, and high-quality diamonds cannot be obtained, which also affects the repeatability and consistency of the production process or experiment.

[0003] The MPCVD equipment currently used in the market is mainly divided into two types: cylindrical cavity and disc-shaped cavity. In cylindrical cavity MPCVD equipment, the substrate holder is positioned by the groove on the base. In disc-shaped cavity MPCVD equipment, the cross section of the base is a plane. The advantage is that when the plasma sphere is eccentric, the position of the substrate holder can be adjusted so that it is directly below the plasma sphere; the disadvantage is also here. If the position of the substrate holder is not adjusted accurately when the plasma sphere is eccentric, the position of the substrate holder deviates from the position directly below the plasma sphere, which will still affect the repeatability and consistency of the production process or experiment.

[0004] In the case where the cross section of the base is a plane, the positioning of the substrate holder on the base in the prior art uses a ruler or a through-hole disc, which has the following defects:

[0005] 1. The ruler estimation method is to use a ruler to measure the distance between the outer diameter of the substrate holder and the outer diameter of the base, measure the distance in several directions, and then determine the position of the substrate holder. The problem with the ruler estimation method is that the position of each experiment is biased and can be in any direction; another problem is that when the plasma sphere is eccentric, the substrate holder may not be able to be adjusted to the position directly below the plasma sphere, resulting in many trial and error times and a waste of time.

[0006] 2. The through-hole disk method is to design a circular ring structure according to the outer diameter of the substrate holder and the base, and the substrate holder is nested in the circular ring structure, and the outer diameter of the ring is concentric with the base. The first problem encountered when using the through-hole disk method is that for a specific substrate holder, its outer diameter is fixed. If the outer diameter of the substrate holder changes, the through-hole disk (circular ring structure) needs to be remade; the second problem is that the inner diameter of the through-hole disk and the substrate holder are in circular surface contact. If the contact between them is too tight, it will cause difficulty in operation and excessive wear during use. If there is a gap or the gap is too large, there will be problems such as inaccurate positioning; the third problem is that the substrate holder can only be placed in the center position of the base, not in other positions on the base, unless the through-hole disk is eccentric, which requires the through-hole disk to be remade (the through-hole disk is concentric with the substrate holder by default. If the substrate holder needs to be eccentric with the outer diameter of the base, it is necessary to remake the through-hole disk with an eccentric center hole). Summary of the invention

[0007] The object of the present invention is to provide a positioning device and a positioning method for a substrate holder in an MPCVD device, which is applicable to the situation where the substrate holder is positioned in any form of MPCVD device when the cross section of the base is a plane. The technical solution adopted by the present invention is as follows:

[0008] A positioning device for a substrate support in an MPCVD device, comprising:

[0009] The fixed support 4 is used to position the substrate support 2 and is a circular ring structure, the inner circular ring surface of which is embedded in the outer circular ring surface of the base 1, and the substrate support 2 is located in the hollow area of ​​the fixed support 4;

[0010] At least three positioning units are distributed along the circumference of the fixed support 4, and the movable end of each positioning unit can move along the radial direction of the fixed support 4, and each movable end is higher than the base 1;

[0011] When each moving end is circumscribed with the outer annular surface of the substrate holder 2 , the positioning of the substrate holder 2 is achieved.

[0012] Preferably, the positioning unit is a lead screw 5 , which is installed in the No. 3 threaded hole 4 - 4 , which extends radially along the fixing bracket 4 and is opened on the No. 2 plane of the fixing bracket 4 .

[0013] Preferably, the circular surface on which the lead screw 5 is mounted on the fixing bracket 4 is milled flat to form a second plane, so as to facilitate the measurement of the distance between the front end surface 5 - 1 of the lead screw 5 and the second plane.

[0014] Preferably, the positioning unit is a No. 1 micrometer knob, which is installed on two steps on the No. 1 plane; the two steps are distributed front and back along the radial direction of the fixed bracket 4, and the micrometer screw of the No. 1 micrometer knob is installed in the hole of the front step;

[0015] The nut of the No. 1 micrometer knob is located in the blind hole groove, the blind hole groove is located between the two steps, and is opened on the No. 1 plane of the fixed bracket 4.

[0016] Preferably, the positioning unit comprises:

[0017] A No. 2 micrometer knob is installed on the front step and the rear step on the No. 1 plane; the two steps are distributed front and back along the radial direction of the fixed bracket 4, and the micrometer screw of the No. 2 micrometer knob is installed in the hole of the front step;

[0018] The extension rod comprises a front rod and a rear rod; the diameter of the front rod is smaller than that of the rear rod, and a cylindrical through hole 11-1 is provided on the rear end surface of the rear rod; the front end surface of the micrometer screw of the No. 2 micrometer knob cooperates with the cylindrical through hole 11-1;

[0019] The light hole on the front step includes a front hole, a middle hole and a rear hole which are connected in sequence, and the inner diameters of the holes increase in sequence;

[0020] The front section rod is placed in the front section hole and the middle section hole, and the rear section rod is placed in the rear section hole;

[0021] The spring is sleeved on the front section rod and located in the middle section hole, with one end affixed to the front end surface of the rear section rod and the other end affixed to the front end surface of the middle section hole.

[0022] Preferably, a first threaded hole 4-2 and a second threaded hole 4-3 are provided on the annular surface of the fixing bracket 4, both of which extend along the radial direction of the fixing bracket 4 and are through holes;

[0023] The second threaded hole 4 - 3 is used to install a locking screw or a set screw to fix the fixing bracket 4 to the outer annular surface of the base 1 ;

[0024] The No. 1 threaded hole 4 - 2 is used to install a plunger, and the plunger is used to determine the position of the fixing bracket 4 on the base 1 .

[0025] A method for positioning a substrate support in an MPCVD device comprises the following steps:

[0026] The position of the positioning unit is adjusted, and when the moving end of the positioning unit is in contact with the outer circumferential surface of the substrate holder 2, the position of the substrate holder 2 is fixed;

[0027] The moving distance of the moving end is recorded to achieve positioning consistency of the substrate holder 2 after each positioning.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] 1. When the outer diameter of the substrate holder changes, the fixed holder does not need to be remade, that is, the device supports substrate holders with different outer diameters.

[0030] 2. The position of the substrate holder relative to the center of the base can be adjusted, that is, the eccentricity of the substrate holder can be adjusted to adapt to the eccentricity of the plasma sphere.

[0031] 3. The end face tangent to the substrate holder is freely fitted, that is, the end face tangent to the outer annular surface of the substrate holder does not have an interference fit or a problem of too large or too small a fit clearance.

[0032] 3. The position of the end face (moving end) of the positioning unit can be accurately measured, so that it can be ensured that the substrate holder is placed in the same position each time, that is, the repeatability and consistency of the production process or experiment are guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of the base;

[0034] Figure 2 The figure is a diagram showing the appearance of a substrate support and a growth substrate placed on a base in the MPCVD device in Example 1;

[0035] Figure 3 The structural diagram of the positioning device of the substrate support in the MPCVD device in Example 1, excluding the positioning unit;

[0036] Figure 4 is a structural diagram of the fixing bracket in Example 1;

[0037] Figure 5 This is an internal structural diagram of a positioning device for a substrate support in an MPCVD device in Example 1;

[0038] Figure 6 It is a structural diagram of the lead screw in Example 1;

[0039] Figure 7 This is an internal structural diagram of a positioning device for a substrate support in an MPCVD device in Example 2;

[0040] Figure 8 is a structural diagram of the fixing bracket in Example 2;

[0041] Fig. 9 This is an internal structural diagram of a positioning device for a substrate support in an MPCVD device in Example 3;

[0042] Fig.10 is a structural diagram of the fixing bracket in Example 3;

[0043] Fig.11 A partial cross-sectional view of the positioning device of the substrate support in the MPCVD equipment in Example 3.

[0044] Among them, 1-base, 1-1, wire groove, 1-2, V-shaped groove,

[0045] 2-substrate holder, 3-growth substrate,

[0046] 4-Fixed bracket, 4-1, shallow wire groove, 4-2, threaded hole No. 1, 4-3, threaded hole No. 2, 4-4, threaded hole No. 3,

[0047] 5-lead screw, 11-1-cylindrical through hole. DETAILED DESCRIPTION

[0048] The positioning device and method of the substrate support in the MPCVD device of the present invention will be described in more detail below in conjunction with the schematic diagram, wherein the preferred embodiment of the present invention is shown, and it should be understood that those skilled in the art can modify the present invention described herein and still achieve the advantageous effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation of the present invention.

[0049] Example 1

[0050] like Figure 1 As shown, the base 1 is a component in the MPCVD equipment, and its upper surface is used to place the substrate holder 2. When the vacuum switch is turned on, the following is generated: Figure 1 The vacuum adsorption force 1-3 in the vacuum adsorption device 2 is used to vacuum adsorb the substrate holder 2 to the base 1, so that the substrate holder 2 does not move when the MPCVD equipment is working.

[0051] like Figure 2 As shown, the substrate holder 2 is placed on the base platform 1 , the single crystal seed wafer or the polycrystalline growth substrate 3 is placed on the substrate holder 2 , and the growth substrate 3 is limited by the groove on the substrate holder 2 .

[0052] Several shallow grooves 1 - 1 are etched on the outer circumferential surface of the base 1 to position the fixed bracket 4 , so that the measurement deviation in the rotation direction will not be generated due to the rotation of the fixed bracket 4 .

[0053] The outer circumferential surface of the base 1 may also have several V-shaped grooves 1-2. A plunger is installed on the fixed bracket 4, and the round ball on the plunger is embedded in the V-shaped groove, which can also realize the positioning of the fixed bracket 4.

[0054] The positioning device of the substrate holder in the MPCVD device determines the position of the substrate holder 2 by the principle of determining the tangent circle by two straight lines.

[0055] Specifically, the position of the substrate holder is determined by utilizing three or more surfaces that are tangent to the outer annular surface of the substrate holder 2 .

[0056] The positions of three or more surfaces are known, and the exact position of the substrate holder 2 can be calculated, and the actual position of the substrate holder can also be simulated by three-dimensional software.

[0057] The two faces are tangent to the outer annular surface of the substrate holder 2, so that the position of the substrate holder can be determined. In addition, at least one face is required to assist in positioning, so generally at least three faces are required, and these three faces are not coplanar.

[0058] In the embodiment, the positioning device of the substrate support in the MPCVD device adopts a screw structure, specifically as follows: Figures 3-4 As shown, including:

[0059] The fixed support 4 is used to position the substrate support 2 and is a circular ring structure with steps.

[0060] The inner annular surface of the fixing bracket 4 is embedded in the outer annular surface of the base 1 , and the substrate bracket 2 is located in the hollow area of ​​the fixing bracket 4 .

[0061] Two types of threaded holes are provided on the annular surface of the fixing bracket 4, extending along the radial direction of the fixing bracket 4, and are through-hole threaded holes. The threaded holes include a No. 1 threaded hole 4-2 and a No. 2 threaded hole 4-3.

[0062] Three steps are arranged on the plane (plane No. 1) of the fixing bracket 4. A threaded hole No. 3 4-4 is arranged on each step, and the threaded hole No. 3 4-4 extends along the radial direction of the fixing bracket 4 for installing a lead screw 5.

[0063] Compared with the solution of arranging a whole circular ring on the No. 1 plane of the fixing bracket 4 to install the lead screw 5 , the setting of the step can reduce the weight of the fixing bracket 4 .

[0064] The No. 1 threaded hole 4-2 is used to install a plunger, and the plunger is used to determine the position of the fixing bracket 4 on the base 1. The fixing bracket 4 may also be engraved with a shallow wire groove 4-1 for alignment with the wire groove 1-1 of the base 1.

[0065] The No. 2 threaded hole 4 - 3 is used to install a locking screw or a set screw to fix the fixing bracket 4 to the outer annular surface of the base 1 .

[0066] That is, the position of the fixing bracket 4 on the base is determined by means of engraved lines or plungers, and the fixing bracket 4 is fastened to the outer annular surface of the base 1 by means of locking screws or set screws.

[0067] The third threaded hole 4-4 is used to install the lead screw 5. The circular surface for installing the lead screw is milled flat, which is convenient for measuring the distance between the front end surface 5-1 of the lead screw 5 and the plane (the second plane), so as to determine the accurate position of the substrate holder 2.

[0068] Lead screw 5, such as Figures 5-6As shown, the front end face is the end facing the substrate holder 2. The front end can be a cylindrical shape without threads. If the material can be quenched, surface treatment is required to enhance the hardness and prevent wear. Among them, the base 1 is lower than the lead screw 5 to ensure that the base 1 does not interfere with the lead screw 5.

[0069] The positions of the three lead screws 5 are adjusted by rotation. When the front end faces of the lead screws 5 are in contact with the outer cylindrical surface of the substrate holder 2, the position of the substrate holder 2 is fixed. At this time, the vacuum switch is turned on and the substrate holder 2 is vacuum-adsorbed onto the base 1.

[0070] Measure the distance from the front end face 5-1 of the lead screw 5 to the second plane of the outer circumference of the fixed support 4, record it, and loosen the lead screw 5. Remove the positioning device, and each subsequent installation of the positioning device can determine the position of the substrate support 2 according to the recorded data without losing accurate positioning.

[0071] In this embodiment, the positioning device has the following advantages:

[0072] 1. When the outer diameter of the substrate holder changes, the fixed holder 4 does not need to be remade, that is, the device supports substrate holders with different outer diameters.

[0073] 2. The position of the substrate holder 2 relative to the center of the base 1 can be adjusted by the lead screw 5, that is, the eccentricity of the substrate holder 2 can be adjusted to adapt to the eccentricity of the plasma sphere.

[0074] 3. The end surface of the positioning device tangent to the substrate support is freely fitted, that is, there is no problem of interference fit or too large or too small fit clearance in the fit of the end surface tangent to the outer annular surface of the substrate support.

[0075] 4. The position of the front end surface 5-1 of the lead screw 5 can be accurately measured, so that it can be ensured that each time the substrate holder is placed, it is in the same position, that is, the repeatability and consistency of the production process or experiment are guaranteed.

[0076] Example 2

[0077] Different from Example 1, the positioning device of the substrate holder in the MPCVD equipment adopts a structure in the form of a large-range micrometer knob.

[0078] like Figures 7-8 , the positioning device of the substrate support in the MPCVD equipment includes:

[0079] The fixing bracket 4 is different from the embodiment 1 in that, for a surface tangent to the outer annular surface of the substrate bracket, two steps and a blind hole groove are correspondingly provided. The holes opened on the two steps are light holes, not threaded holes.

[0080] 2 steps are used to install the micrometer knob with a large range, that is, the No. 1 micrometer knob 6, also known as the differential head.

[0081] The front and rear steps are distributed along the radial direction of the fixed support 4, including a front step (a step facing the substrate support 2) and a rear step. A micrometer screw of a No. 1 micrometer knob is installed in the hole of the front step.

[0082] The blind hole groove is located between the two steps. The blind hole groove is used to place the nut for installing the large-range micrometer knob (fix the micrometer knob on the back step), and the groove depth ensures that it does not affect the installation of the nut.

[0083] The micrometer knob, also called the differential head, is made based on the principle of spiral amplification. The specific working method is as follows: when the differential cylinder rotates one circle, the micrometer screw moves forward or backward along the rotation axis by a lead distance; when the differential cylinder rotates one grid, the micrometer screw moves a minimum unit (for example, 0.01mm).

[0084] Similarly, the positions of the micrometer screws in the three micrometer knobs are adjusted by rotating the differential cylinder. When the front end surface of the micrometer screw fits the outer cylindrical surface of the substrate holder 2, the position of the substrate holder 2 is fixed. At this time, the vacuum switch is turned on and the substrate holder 2 is vacuum adsorbed onto the base 1.

[0085] Among them, the micrometer knob can directly read the specific measurement value, that is, the moving distance of the micrometer screw.

[0086] The No. 1 micrometer knob provides accurate measurement and easy adjustment.

[0087] Example 3

[0088] On the basis of Example 2, an extension rod and a spring (in compressed state) are added, the front step is lengthened, and the No. 1 micrometer knob is replaced with a No. 2 micrometer knob (a micrometer knob of normal range).

[0089] like Figures 9-11 The rear end face of the extension rod is provided with a cylindrical through hole 11-1, and the front end face of the micrometer screw of the micrometer knob is placed here, that is, matched with the cylindrical through hole 11-1.

[0090] The extension rod comprises a front section rod and a rear section rod.

[0091] The diameter of the front section rod is smaller than the diameter of the rear section rod, and the cylindrical through hole 11 - 1 is opened on the rear end surface of the rear section rod.

[0092] The light hole on the front step includes a front hole, a middle hole and a rear hole which are connected in sequence, and the inner diameters thereof increase in sequence.

[0093] The front section rod is placed in the front section hole and the middle section hole, and the rear section rod is placed in the rear section hole.

[0094] The spring is sleeved on the front section rod and located in the middle section hole, with one end affixed to the front end surface of the rear section rod and the other end affixed to the front end surface of the middle section hole.

[0095] That is, one side of the spring is attached to the front end face of the middle hole of the fixing bracket 4, and the other side is attached to the end face of the stepped shaft of the extension rod (the front end face of the rear rod).

[0096] When the No. 2 micrometer knob is at the maximum and minimum limit positions, the compression spring maintains a certain elastic force (in a compressed state) to ensure that the extension rod fits onto the micrometer screw of the micrometer knob.

[0097] Because the micrometer screw extending from the micrometer knob is limited in length, an extension rod is connected to the front section, and the rear end face of the extension rod is attached to the front end face of the micrometer screw of the micrometer knob through a spring. When the micrometer screw of the micrometer knob is extended or shortened, the extension rod moves synchronously. The commonly used micrometer knob is generally selected according to the range of the substrate holder to be offset.

[0098] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A positioning device for a substrate support in an MPCVD device, characterized in that: include: The fixed support (4) is used to position the substrate support (2) and is a circular ring structure, the inner circular ring surface of which is embedded in the outer circular ring surface of the base (1), and the substrate support (2) is located in the hollow area of ​​the fixed support (4); At least three positioning units are distributed along the circumference of the fixed support (4), and the movable end of each positioning unit can move along the radial direction of the fixed support (4), and each movable end is higher than the base (1); the base (1) is a component in the MPCVD device, and its upper plane is used to place the substrate support (2); When each movable end is circumscribed with the outer annular surface of the substrate holder (2), the substrate holder (2) is positioned; after the position of the substrate holder (2) is fixed, the positioning device is removed.

2. The positioning device for a substrate support in an MPCVD device according to claim 1, characterized in that: The positioning unit is a lead screw (5), which is installed in a No. 3 threaded hole (4-4). The No. 3 threaded hole (4-4) extends radially along the fixed bracket (4) and is opened on the No. 2 plane of the fixed bracket (4).

3. The positioning device for a substrate support in an MPCVD device according to claim 2, characterized in that: The circular surface of the fixed bracket (4) on which the lead screw (5) is mounted is milled flat to form a second plane, so as to facilitate the measurement of the distance between the front end surface (5-1) of the lead screw (5) and the second plane.

4. The positioning device for a substrate support in an MPCVD device according to claim 1, characterized in that: The positioning unit is a No. 1 micrometer knob, which is installed on two steps on the No. 1 plane; the two steps are distributed front and back along the radial direction of the fixed bracket (4), and the micrometer screw of the No. 1 micrometer knob is installed in the hole of the front step; The nut of the No. 1 micrometer knob is located in the blind hole groove, the blind hole groove is located between the two steps and is opened on the No. 1 plane of the fixed bracket (4).

5. The positioning device for a substrate support in an MPCVD device according to claim 1, characterized in that: The positioning unit comprises: A second micrometer knob is mounted on the front step and the rear step on the first plane; the two steps are distributed front and back along the radial direction of the fixed bracket (4), and the micrometer screw of the second micrometer knob is mounted in the hole of the front step; The extension rod comprises a front rod and a rear rod; the diameter of the front rod is smaller than that of the rear rod, and a cylindrical through hole (11-1) is provided on the rear end surface of the rear rod; the front end surface of the micrometer screw of the No. 2 micrometer knob matches the cylindrical through hole (11-1); The light hole on the front step includes a front hole, a middle hole and a rear hole which are connected in sequence, and the inner diameters of the holes increase in sequence; The front section rod is placed in the front section hole and the middle section hole, and the rear section rod is placed in the rear section hole; The spring is sleeved on the front section rod and located in the middle section hole, with one end affixed to the front end surface of the rear section rod and the other end affixed to the front end surface of the middle section hole.

6. The positioning device for a substrate support in an MPCVD device according to claim 1, characterized in that: A first threaded hole (4-2) and a second threaded hole (4-3) are provided on the annular surface of the fixing bracket (4), both of which extend in the radial direction of the fixing bracket (4) and are through holes; A second threaded hole (4-3) for installing a locking screw or a set screw to fix the fixing bracket (4) to the outer annular surface of the base (1); The No. 1 threaded hole (4-2) is used to install a plunger, and the plunger is used to determine the position of the fixing bracket (4) on the base (1).

7. A method for positioning a substrate support in an MPCVD device, based on the positioning device for a substrate support in an MPCVD device according to any one of claims 1 to 6, characterized in that: The following steps are involved: The position of the positioning unit is adjusted, and when the movable end of the positioning unit is in contact with the outer circumferential surface of the substrate holder (2), the position of the substrate holder (2) is fixed; The moving distance of the moving end is recorded to achieve positioning consistency of the substrate holder (2) after each positioning.

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