CN214271039U

CN214271039U - Substrate tray and reactor with same

Info

Publication number: CN214271039U
Application number: CN202023270678.1U
Authority: CN
Inventors: 姜勇; 丁伟
Original assignee: Advanced Micro Fabrication Equipment Inc Shanghai
Current assignee: Advanced Micro Fabrication Equipment Inc Shanghai; Advanced Micro Fabrication Equipment Inc
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-09-24
Anticipated expiration: 2030-12-30

Abstract

A substrate tray for supporting a substrate to be processed and a reactor in which the substrate tray is arranged are used for inversely mounting the substrate to perform film growth. The substrate tray comprises a side wall and a central opening formed by surrounding the side wall, the inner side of the side wall comprises a first step part and is used for placing a heat diffusion plate, a second step part is arranged below the first step part, a heat insulation device is arranged on the upper surface of the second step part and is used for supporting a first surface of a substrate to be processed, and the diameter of the inner side wall of the first step part is larger than that of the inner side wall of the second step part.

Description

Substrate tray and reactor with same

Technical Field

The utility model relates to a semiconductor field especially relates to a substrate tray and reactor technical field that is used for compound semiconductor epitaxial material to grow.

Background

There is an increasing demand for compound semiconductor epitaxial materials, typically gallium nitride materials, which can be used in LED and power device fabrication. A commonly used reactor for compound semiconductor materials includes a Metal Organic Chemical Vapor Deposition (MOCVD) reactor, the MOCVD reactor includes a reaction chamber, a rotating substrate tray is arranged at the bottom in the reaction chamber, a heater is arranged below the substrate tray and used for heating the substrate tray, a substrate to be processed is arranged on the substrate tray, an air inlet device is arranged above the inside of the reactor, reaction gas flowing from the air inlet device flows to the substrate arranged on the upper surface of the tray, and a required epitaxial material layer is generated on the upper surface of the substrate by growth. With the development of industrial demands, the requirements of micro/mini LEDs on the uniformity of an epitaxial layer above a substrate are higher and higher, and the requirements on the upper limit of the amount of particulate matters are also higher and higher. The gas inlet device above the substrate in the existing MOCVD reactor can generate a large amount of particles in the reaction process, and the particles move along with the gas flow or are attracted by gravity to fall onto the upper surface of the substrate, so that the structure of the LED chip with tiny size is damaged.

In order to prevent particles from falling onto the substrate, a new substrate tray structure is needed in the industry, so that the particles are reduced when the substrate is subjected to epitaxial growth, the temperature on the substrate has extremely high uniformity, and the substrate is optimally and easily loaded and unloaded, so that the automatic operation in a vacuum environment is realized, and the particles are prevented from being brought in.

Disclosure of Invention

In order to solve the technical problem, the utility model provides a substrate tray for supporting substrate, substrate tray includes that lateral wall and lateral wall center around the central opening that forms, the inboard of lateral wall includes that first step portion is used for placing a thermal diffusion plate, first step portion below includes a second step portion, the upper surface of second step portion is provided with a heat-proof device, heat-proof device is used for supporting the first surface of pending substrate, the inside wall diameter of first step portion is greater than second step portion inside wall diameter.

Optionally, the heat insulation device includes a heat insulation ring, a bottom surface of the heat insulation ring is placed on the second step portion, a top of the second step portion includes a supporting surface for supporting the substrate to be processed, and a vertical sidewall surrounds the supporting surface.

Optionally, the heat shield comprises a heat shield ring, the top of the heat shield ring comprises a plurality of upwardly projecting ribs, and the substrate is placed on the plurality of upwardly projecting ribs.

Optionally, the bottom surface of the heat insulation ring includes a plurality of ribs protruding downward, and the heat insulation ring is in contact with the second stepped portion through the plurality of ribs.

Optionally, the heat insulation device includes a plurality of support claws arranged separately in a circumferential direction, the support claws are arranged on the second step portion, and at least part of the top portion is used for supporting the substrate.

Optionally, the support claw includes a horizontal extension portion and a vertical extension portion, wherein a bottom plane of the horizontal extension portion is placed on the second step portion, and a top cross section of the horizontal extension portion is smaller than the bottom plane.

Optionally, the vertical extension is located outside the horizontal extension, and the cross section of the vertical extension near the central open end of the substrate tray is tapered, so that the contact area of the substrate sidewall and the vertical extension is minimized.

Optionally, the support claw includes a tray connecting portion, a lower extension portion, and a substrate support portion, a bottom surface of the tray connecting portion is supported by a top surface of the second stepped portion, one end of the lower extension portion is connected to the tray connecting portion, the other end of the lower extension portion extends downward and is connected to the substrate support portion, and a top of the substrate support portion is used for supporting the substrate to be processed such that the first surface of the substrate is lower than the top surface of the second stepped portion.

Optionally, the substrate support extends in a horizontal direction, wherein the cross-section of the top portion is smaller than the cross-section of the bottom portion of the substrate support.

Optionally, the lower extension is tapered in cross-section proximate the central open end of the substrate tray such that the contact area of the substrate sidewalls with the vertical extension is minimized.

Optionally, the thermal isolation device is made of a material having a first thermal conductivity and the substrate tray is made of a material having a second thermal conductivity, wherein the first thermal conductivity is less than 1/4 of the second thermal conductivity.

Optionally, the thermal conductivity of the thermal insulation device is less than or equal to 40W/m.k, and the thermal conductivity of the substrate tray is greater than or equal to 150W/m.k.

Further, the utility model also provides a reactor, including a reaction chamber, the reaction intracavity sets up as above the substrate tray.

The utility model has the advantages that: the utility model provides a substrate tray of flip-chip MOCVD reactor and reactor at place thereof, wherein the substrate tray includes that first step portion is used for placing the thermal diffusion plate, still includes second step portion, wherein places a support ring of being made by thermal insulation material on the second step portion to carry out horizontal heat transmission through the conduction between reduction substrate marginal zone and the substrate tray. The diameter of the inner side wall of the first step part is larger than that of the inner side wall of the second step part. The heat insulating material can be made of ceramic materials such as alumina, quartz, sapphire and the like, the heat conduction coefficients of the alumina, the quartz and the sapphire materials are only 4, 20 and 40W/m.k, and the heat conduction coefficients of the traditional substrate tray materials such as graphite and silicon carbide materials can reach 150-490W/m.k. By using the thermal insulation material, the heat conduction between the edge of the substrate and the substrate tray can be greatly reduced, thereby improving the temperature uniformity in the center to edge area of the substrate and improving the uniformity of the growth quality of the epitaxial material on the substrate.

Drawings

Fig. 1 is a schematic structural view of an inverted MOCVD reactor of the present invention;

fig. 2 is a schematic view of a substrate tray for a flip-chip MOCVD reactor of the present invention;

figure 3a is a schematic view of a second embodiment of the present invention of a substrate tray for a flip-chip MOCVD reactor;

FIGS. 3b and 3c are schematic views of a third embodiment of a carrier ring structure for a substrate tray according to the present invention;

fig. 4a and 4b are views of a fourth embodiment of the substrate tray of the present invention for use in a flip-chip MOCVD reactor;

fig. 5a is a schematic view of a fifth embodiment of the substrate tray of the present invention for use in a flip-chip MOCD reactor;

fig. 5b is a schematic view of a fifth embodiment of a substrate holding claw of the substrate tray of fig. 5 a.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Fig. 1 is a schematic structural diagram of a flip-chip MOCVD reactor of the present invention, and as shown in fig. 1, the flip-chip substrate reaction chamber includes a heater in the top cavity 1, which may be a plurality of independent heaters H1, H2 with temperature controlled by zones. The lower part of the heater comprises a substrate tray 8, the inner side of the substrate tray 8 comprises an annular first step part 81 used for placing a heat diffusion plate 9, and a second step part 82 positioned below the first step part and used for placing a substrate to be processed, wherein the back surface of the substrate faces the heat diffusion plate 9, and the edge of the surface to be processed is supported by the second step part 82 and faces the bottom of the lower reaction chamber. Wherein, a gap 11 is also arranged between the heat diffusion plate 9 and the back surface of the substrate, after the heat from the heaters H1 and H2 heats the heat diffusion plate 9 by radiation, the heat diffusion plate 9 radiates and heats the back surface of the substrate 10 below through the gap 11. Wherein the substrate tray 8 and the thermal diffusion plate are made of a highly heat conductive material such as graphite, SiC, etc. Since there is a surface directly contacting the step 82 at the edge region of the processing surface of the substrate 10, a large amount of heat flows laterally between the step 82 and the substrate 10 through the contact surface of the edge, which may cause a large difference between the temperature of the edge region of the substrate and the temperature of the central region, and this temperature difference cannot be compensated by controlling the power of the upper heater. For supporting and driving the substrate tray in rotation, a drive disc 7 is included around the periphery of said substrate tray 8, so that the substrate tray 8 rotates during the process. The bottom of the reaction chamber may also include a plurality of probes S1, S2 for detecting temperature, thickness, degree of deformation, etc. on the substrate above. A controller 12 controls the heating power and the ratio of the upper heater based on the parameters obtained from the probes. One side below the substrate tray 8 and the drive plate 7 comprises a gas inlet means 3 for introducing reaction gas into the reaction space below the substrate tray, and a gas outlet means 4 for discharging the reacted gas out of the reaction chamber is provided at a position opposite to the gas inlet means 3.

In addition, the flip-chip substrate tray has high difficulty in loading and unloading the substrate, and when loading, the substrate needs to be sucked by the suction cup and placed on the second step part 82, and then the heat diffusion plate 9 needs to be sucked and placed on the first step part 81; when unloading, the temperature of the substrate tray needs to be reduced to a certain degree, the sucker is extended into the reaction cavity to suck the thermal diffusion plate 9 and then is moved out of the reaction cavity, then the sucker is used for sucking the substrate from the back of the substrate 10 and then is moved out of the reaction cavity, and the substrate 10 needs to be turned over after being moved out of the reaction cavity, so that the processing surface of the substrate is placed on a corresponding fixing frame after facing upwards. This kind of process action of absorbing repeatedly, removing, upset is very complicated, can't use low-cost arm to accomplish, often uses artifical the completion, and this can lead to a large amount of particulate matters to adsorb on the substrate in substrate transfer process, finally makes the advantage of the few particulate matters that flip-chip substrate reaction chamber brought weaken by a wide margin.

Based on the above-mentioned technical problem, the inventor proposes a novel substrate tray structure. Fig. 2 is a schematic diagram of a substrate tray for a flip-chip MOCVD reactor, wherein the substrate tray 8 comprises a first step portion 81 for placing the thermal diffusion plate 9 and a second step portion 82 ', wherein a support ring 84 made of a thermal insulation material is placed on the second step portion 82' to reduce the lateral heat transfer between the edge region of the substrate and the substrate tray 8 through conduction. Wherein the diameter of the inner sidewall 81S of the first step portion 81 is larger than the diameter of the inner sidewall 82 'S of the second step portion 82'. The heat insulating material can be made of ceramic materials such as alumina, quartz, sapphire and the like, the heat conduction coefficients of the alumina, the quartz and the sapphire materials are only 4, 20 and 40W/m.k, and the heat conduction coefficients of the traditional substrate tray materials such as graphite and silicon carbide materials can reach 150-490W/m.k. By using the thermal insulation material, the heat conduction between the edge of the substrate and the substrate tray can be greatly reduced, thereby improving the temperature uniformity in the center to edge area of the substrate and improving the uniformity of the growth quality of the epitaxial material on the substrate. Support ring 84 comprises an L-shaped cross-section with a bottom surface that mates with second step 82' and an upper surface that includes an insulating step on which the substrate rests.

In order to further reduce the heat conduction between the substrate W and the substrate tray 8, the present invention provides the substrate tray as shown in fig. 3a, wherein the second step portion 82' is provided with a support ring 85 made of heat-insulating ceramic material, and the support ring is still L-shaped in cross section. As shown in fig. 3b and 3c, the bottom surface of the support ring 85 comprises a plurality of elongated ribs 852 protruding from the bottom surface, the inner side of the upper surface of the support ring 85 comprises a plurality of L-shaped raised ribs 851, wherein the raised ribs comprise vertical extensions 851a and horizontal extensions 851b, the edge of the material growth surface of the substrate to be processed is supported by the horizontal extensions 851, and the sidewall of the substrate to be processed may be in contact with the inner sidewall of the vertical extensions 851 b. The lower surface of the support ring 85 is also provided with corresponding ribs 852, which ribs 852 further reduce the actual contact area between the support ring 85 and the substrate 10 and between the support ring 85 and the lower step 82', which also greatly reduces the heat flux between the substrate 10 and the second step. Wherein the inner sidewalls of the vertical extension 851 are not necessarily perfectly 90 degrees perpendicular to the plane of the substrate, but may be inclined downward to allow the substrate to be self-centered with respect to the support ring 85 when the substrate is placed.

In order to simplify the structure of the substrate tray 8 of the present invention, the inventors propose a substrate tray of another embodiment. As shown in fig. 4a, the inner wall of the through hole inside the substrate tray 8 includes a plurality of independent support claws 86 uniformly distributed on the circular ring-shaped support surface of the second stepped portion 82 ″, which eliminates the need for a support ring to be disposed between the substrate and the second stepped portion. The supporting jaw 86 is also made of a heat-insulating ceramic material, and its specific structure is shown in fig. 4b, and includes a vertical extension 86a and a horizontal extension 86 b. The horizontal extension portion 86b has a triangular prism shape, wherein the bottom area is large so that the supporting claw 86 is stably fixed on the second stepped portion 82 ″, and the upper end is a ridge line 86b1, so that only a linear contact region exists between the edge region of the substrate and the supporting claw 86, and the conductive heat between the substrate and the supporting claw 86 is greatly reduced. The vertical extensions 86a are similar in construction to the vertical extensions 86b except that the outer sidewalls have a larger area to allow the outer sidewalls of the support fingers to closely contact the inner walls of the substrate tray above the step 82 ", while the innermost side of the vertical extensions 86a is a ridge 86a1 to allow the substrate sidewalls to contact the support fingers with only linear contact areas, which also reduces heat conduction in the direction of the substrate sidewalls. Wherein the cross-section of the support claws 85 may be other polygonal shapes as well, so long as the area in contact with the substrate has a tapered cross-section to minimize the contact surface between the substrate and the support claws.

The support rings 84, 85 and the support claws 86 can greatly reduce the heat conduction between the edge area of the substrate and the second stepped portion, but the substrate is erected above the second stepped portion and the support rings/claws, the lower surface of the substrate for material layer growth is higher than the bottom surface 80 of the substrate tray 8, which causes the reaction gas to flow through the bottom surface 80 of the substrate tray in the horizontal direction, when reaching the edge of the substrate, the gas flow is diverted upwards to the recessed area, which causes chaotic vortex flow in the edge area of the substrate, and the disturbance of the gas flow distribution causes the non-uniformity of the thickness or crystal structure of the material layer grown on the substrate, thus seriously affecting the growth quality of the material layer on the surface of the substrate 10. In order to further solve the problem of uneven distribution of the airflow on the surface of the substrate, the inventor proposes a substrate tray 8 as shown in fig. 5a, the basic structure of which is the same as that of the previous embodiments, and the main improvement is characterized by a plurality of newly formed support claws 87. As shown in fig. 5b, the support claw 87 includes a tray connecting portion 87a, a lower extension 87b, and a substrate support portion 87 c. Wherein the tray connecting portion 87a is fixed above the second stepped portion 82' ″ of the substrate tray 8, and the lower extension portion 87b extends downward from the inner end of the tray connecting portion by a distance to be connected to the outer end of the substrate supporting portion 87 c. Wherein the top of the substrate support portion 87c includes a raised ridge 87c1 for supporting the substrate to be processed, and the lower extension may be designed to include a ridge 87b1 to minimize heat transfer between the support fingers 87 and the edge regions of the substrate. Wherein the downward extension of the lower extension 87b is optimally designed such that the height of 87c1 is approximately the same as the height of the bottom surface 80 of the substrate tray so that the substrate to be processed, which is held on the substrate support 87c, has substantially the same height as the bottom surface 80 of the substrate tray so that there is a steady distribution of gas flow over the substrate during processing and a high quality layer of material is grown.

In the embodiment shown in fig. 4a, 4b, 5a and 5b of the present invention, a plurality of support claws can be replaced with new support claws or support claws with new shapes can be selected according to the process requirements. The physical properties of the surface materials of the substrate tray and support rings and support jaws gradually change after prolonged use in the MOCVD reactor. Adopt the utility model discloses can replace the change support claw that can be convenient behind the support claw, and need not dismantle whole substrate tray for the reaction chamber can maintain in the best state for a long time. Or when the local area temperature is too high or too low according to the result of the treatment process, the supporting claws at the corresponding positions on the substrate tray are selected to be replaced by the supporting claws with smaller contact surfaces or larger contact surfaces, thus the substrate tray and the optional supporting claws with the structure can also be used as an optional means for adjusting the uniformity of the surface temperature of the substrate.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present invention, and the scope of the present invention is defined by the appended claims.

Claims

1. A substrate tray for supporting a substrate, comprising: the substrate tray comprises a side wall and a central opening formed by surrounding the side wall, the inner side of the side wall comprises a first step part and is used for placing a heat diffusion plate, a second step part is arranged below the first step part, a heat insulation device is arranged on the upper surface of the second step part and is used for supporting a first surface of a substrate to be processed, and the diameter of the inner side wall of the first step part is larger than that of the inner side wall of the second step part.

2. The substrate tray of claim 1, wherein the thermal isolation device comprises an isolation ring having a bottom surface disposed on the second step portion, the top of the second step portion comprising a support surface for supporting the substrate to be processed and a vertical sidewall surrounding the support surface.

3. The substrate tray of claim 1, wherein the thermal shield comprises an insulating ring, a top of the insulating ring comprising a plurality of upwardly projecting ribs, the substrate being placed on the plurality of upwardly projecting ribs.

4. The substrate tray of claim 3, wherein the bottom surface of the thermal ring includes a plurality of downwardly projecting ribs, the thermal ring contacting the second step portion via the plurality of ribs.

5. The substrate tray according to claim 1, wherein the heat insulating means comprises a plurality of support claws arranged separately in a circumferential direction, the support claws being provided on the second stepped portion and at least a part of the top portion being for supporting the substrate.

6. The substrate tray of claim 5, wherein the support claw includes a horizontally extending portion and a vertically extending portion, wherein a bottom plane of the horizontally extending portion is placed on the second stepped portion, and a top cross-section of the horizontally extending portion is smaller than the bottom plane.

7. The substrate tray of claim 6, wherein the vertical extension is positioned outside of the horizontal extension, and wherein the vertical extension has a tapered cross-section proximate the central open end of the substrate tray to minimize the contact area of the substrate sidewall with the vertical extension.

8. The substrate tray according to claim 6, wherein the support claw includes a tray connecting portion, a lower extension portion and a substrate supporting portion, a bottom surface of the tray connecting portion is supported by a top surface of the second stepped portion, the lower extension portion is connected to the tray connecting portion at one end and extends downward at the other end and is connected to the substrate supporting portion at a top portion thereof for supporting the substrate to be processed such that the first surface of the substrate is lower than the top surface of the second stepped portion.

9. The substrate tray of claim 8, wherein the substrate support extends in a horizontal direction, wherein a cross-section of the top portion is smaller than a cross-section of the bottom portion of the substrate support.

10. The substrate tray of claim 8, wherein the lower extension has a tapered cross section proximate the central open end of the substrate tray such that the contact area of the substrate sidewalls with the vertical extension is minimized.

11. The substrate tray of claim 1, wherein the thermal isolation device is formed from a material having a first thermal conductivity and the substrate tray is formed from a material having a second thermal conductivity, wherein the first thermal conductivity is less than 1/4 of the second thermal conductivity.

12. The substrate tray of claim 1, wherein the thermal conductivity of the thermal isolation device is 40W/m.k or less and the thermal conductivity of the substrate tray is 150W/m.k or more.

13. A reactor comprising a reaction chamber, wherein: a substrate tray as claimed in any one of claims 1 to 12 disposed within the reaction chamber.