TWI821766B - Thin film growth systems and substrate tray and carrier ring elements - Google Patents

Abstract

The invention provides a substrate tray, a carrier ring element and a film growth system for supporting a substrate. The substrate tray includes side walls and a heating chamber surrounded by the side walls. The top of the side walls includes a cover plate, and the top cover is used to radiate heat downward; the inner side of the side wall below the top cover includes a plurality of Support chambers separated from each other, and a lifting chamber adjacent to each support chamber, the bottom of the lifting chamber extends downward and passes through the bottom surface of the side wall of the substrate tray, so that the lifting chamber is connected with the space below the substrate tray Communicated, the bottom plane of the support cavity is higher than the bottom surface of the substrate tray. When matched with the corresponding carrier ring component, the substrate can be picked up and placed from the bottom of the substrate tray, simplifying the process of picking and placing the substrate.

Description

Thin film growth systems and substrate tray and carrier ring elements

The present invention relates to the technical field of semiconductors, and in particular to a thin film growth system for compound semiconductor epitaxial material growth, as well as a substrate tray and a carrier ring element.

The demand for compound semiconductor epitaxial materials is becoming more and more widespread. Typical materials such as gallium nitride can be used in LED and power component manufacturing. Commonly used compound semiconductor material reactors include metal organic chemical vapor phase reactors (MOCVD). The MOCVD reactor includes a reaction chamber with a rotating substrate tray at the bottom and a heater below the substrate tray for heating the substrate tray. , the substrate to be processed is set on the substrate tray, and the upper part of the reactor includes an air inlet device. The reaction gas flowing in from the air inlet device flows to the substrate set on the upper surface of the tray, and grows on the upper surface of the substrate to produce the required epitaxial material. layer. With the development of industrial needs, micro/mini LEDs have increasingly higher requirements for the uniformity of the epitaxial layer above the substrate, and at the same time, the requirements for the upper limit of the number of particulate matter are also getting higher and higher. The air inlet device located above the substrate in the existing MOCVD reactor will produce a large amount of particles during the reaction process. These particles move with the air flow or are attracted by gravity and fall to the upper surface of the substrate, causing structural damage to the tiny LED chip.

In order to prevent particles from falling onto the substrate, the industry needs a new substrate tray structure that can reduce particles during epitaxial growth of the substrate. At the same time, the temperature on the substrate has extremely high uniformity. It also needs to be easy to load and unload. Substrate to achieve automated operation in a vacuum environment and avoid the introduction of particulate matter.

In order to solve the above technical problems, the present invention provides a substrate tray that supports a substrate. The substrate tray includes side walls and a heating chamber surrounded by the side walls. The top of the side walls includes a cover plate, and the cover plate is used to The inner side of the side wall below the cover plate includes a plurality of recessed cavities, the plurality of cavities include a plurality of mutually separated support cavities, and a lifting cavity adjacent to each support cavity. , the bottom of the lifting cavity extends downward and passes through the bottom surface of the side wall of the substrate tray, so that the lifting cavity is connected to the space below the substrate tray, and the bottom plane of the support cavity is higher than the bottom surface of the substrate tray .

Preferably, the bottom of the side wall further includes an annular groove connected to the lifting chamber for accommodating an annular carrier ring.

Preferably, the top of the side wall includes a step portion, and the cover plate is a heat diffusion plate set up on the step portion.

Preferably, the cover plate includes a combination of at least one ring and a circular plate, wherein at least one ring or circular plate is replaceable.

Preferably, a transfer chamber is further included between the support chamber and the lifting chamber, wherein the height of the bottom surface of the transfer chamber is higher than the height of the bottom surface of the support chamber.

Preferably, the support chamber, transfer chamber, and lifting chamber are arranged along the circumferential direction on the inner wall of the substrate tray, and together form a support unit, and multiple support units are spaced apart from each other at the bottom of the side wall of the substrate tray.

Preferably, the bottom surface of the support cavity includes a convex part or a recessed part.

Furthermore, the present invention also provides a carrier ring element for supporting a substrate. The carrier ring element includes: a carrier ring; a plurality of carrier ring supporting claws arranged on the carrier ring at intervals, each of the carrier rings One end of the support claw is fixed to the carrier ring, and the other end extends toward the outside of the carrier ring; and a plurality of substrate support claws spaced apart from each other on the carrier ring, one end of each substrate support claw is fixed to the carrier ring, and the other end Extends toward the inside of the carrier ring to support the substrate.

Preferably, at least one of the carrier ring, carrier ring support claw, and substrate support claw is made of low thermal conductivity material with a thermal conductivity of less than or equal to 40W/m.k, and the other parts are made of high thermal conductivity material with a thermal conductivity of greater than or equal to 150W/m.k. coefficient material.

Preferably, the substrate supporting claws are made of low thermal conductivity material.

Preferably, the substrate support claw includes a fixed section fixed to the carrier ring, a horizontal support section for supporting the substrate, and a transition section connected between the fixed section and the horizontal support section, wherein the transition section is from the fixed section to the support ring. The segment extends downward.

Preferably, the top section of the horizontal support section is tapered with a smaller top and a larger bottom, so as to minimize the contact surface between the top of the horizontal support section and the substrate.

Preferably, the bottom surface of the carrier ring support claw includes a convex portion or a recessed portion to prevent the carrier ring support claw from sliding.

Further, the present invention also provides a thin film growth system. The thin film growth system includes a reaction chamber. The reaction chamber includes a substrate tray as described above located on the top of the reaction chamber. The bottom of the substrate tray includes an air inlet. A device for inputting reaction gas and growing a material layer at the bottom of the substrate tray, and a heater is included above the substrate tray for heating the cover plate of the substrate tray.

Preferably, the thin film growth system further includes a transfer chamber, the transfer chamber includes a mechanical transfer device, the mechanical transfer device includes a transfer head, and the transfer head is used to support the above-mentioned carrier ring. element, and drives the carrier ring support part in the carrier ring element to enter the lifting cavity in the substrate tray and rotate a preset angle along the circumferential direction of the carrier ring.

The advantage of the present invention is that the present invention provides an inverted substrate tray for supporting substrates. The substrate tray includes side walls and a heating chamber surrounded by the side walls. The top of the side walls includes a cover plate, and the top cover Used to radiate heat downward; the inner side of the side wall below the top cover includes a plurality of mutually separated support chambers, and a lifting chamber adjacent to each support chamber, the bottom of the lifting chamber extends downward and Passing through the bottom surface of the side wall of the substrate tray, the lifting cavity is connected to the space below the substrate tray, and the bottom plane of the support cavity is higher than the bottom of the substrate tray. noodle. When matched with the corresponding carrier ring component, the substrate can be picked up and placed from the bottom of the substrate tray, simplifying the process of picking and placing the substrate.

1:Top cavity

10. W: substrate

11: Gap

12:Controller

180:Open your mouth

181:Transfer chamber

181a: Bottom surface of transfer chamber

182:Carrying Ring

183:Support cavity

183a: Bottom surface of support cavity

188:Substrate support claw

188a: Fixed segment

188b: Horizontal support section

189:Carrying ring support claw

3: Air intake device

4:Exhaust device

7:Driver disk

8:Substrate tray

80:Bottom of substrate tray

81:The first step

82: The second step

9: Thermal diffusion plate

9a: Ring-shaped heat diffusion plate

9b: Circular heat diffusion plate

H1, H2: heater

S1, S2: probe

Figure 1 is a schematic structural diagram of a flip-chip MOCVD reactor of the present invention; Figures 2a and 2b are side cross-sectional views and top views of the carrier ring element used in the flip-chip MOCVD reactor; Figure 3a is the same as shown in Figures 2a and 2b The bottom view of the carrier ring component and the corresponding substrate tray after assembly; Figure 3b is a cross-sectional view of the substrate carrier ring and substrate tray assembly at X in Figure 3a; Figure 3c is the substrate carrier ring and substrate in Figure 3a Cross-sectional view of the sheet tray assembly at Y.

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those with ordinary skill in the technical field to which the present invention belongs without making any progressive changes shall fall within the scope of protection of the present invention.

Figure 1 is a schematic structural diagram of a flip-chip MOCVD reactor of the present invention. As shown in Figure 1, the flip-chip substrate reaction chamber includes a heater in the top cavity 1. The heater can be multiple independent heaters with zoned temperature control. H1, H2. A substrate tray 8 is included below the heater. The inner side of the substrate tray 8 includes an annular first step portion 81 for placing the heat diffusion plate 9, and a second step portion 82 located below the first step portion 81. , used to place the substrate to be processed, where the back side of the substrate faces the thermal diffusion plate 9, and the edge of the surface to be processed is supported by the second step portion 82 and faces the bottom of the reaction chamber below. There is also a gap 11 between the thermal diffusion plate 9 and the back of the substrate. After the heat from the heaters H1 and H2 heats the thermal diffusion plate 9 through radiation, the thermal diffusion plate 9 radiates downward through the gap 11 to heat the back of the substrate 10 below. . The substrate tray 8 and the thermal diffusion plate 9 are both made of high thermal conductivity materials, such as graphite, SiC, etc. In the edge area of the processing surface of the substrate 10 due to the presence of the second The step portion 82 is in direct contact with the surface, so a large amount of heat flows laterally between the second step portion 82 and the substrate 10 through the edge contact surface. This will cause the temperature difference between the edge area and the central area of the substrate 10 to be too large, and this Temperature differences cannot be compensated by controlling the power of the heater above. In order to support and drive the substrate tray 8 to rotate, a driving disk 7 is included around the periphery of the substrate tray 8 so that the substrate tray 8 rotates during process processing. The bottom of the reaction chamber may also include multiple probes S1 and S2 for detecting parameters such as temperature, thickness, degree of deformation, etc. on the upper substrate. A controller 12 controls the heating power and proportion of the upper heater based on the parameters obtained by these probes S1, S2. The side below the substrate tray 8 and the drive plate 7 includes an air inlet device 3 for inputting the reaction gas into the reaction space below the substrate tray 8. The position opposite to the air inlet device 3 includes an exhaust device 4 to remove the reaction gas. The gas is discharged from the reaction chamber.

In addition, this kind of flip-chip substrate tray is also very difficult to load and unload the substrate. When loading, it is necessary to use a suction cup to suck the substrate and put it on the second step part 82, and then suck the heat diffusion plate 9 and put it on the first step part 82. On the step part 81; when unloading, you need to wait for the temperature of the substrate tray to drop to a certain level, insert the suction cup into the reaction chamber to suck the heat diffusion plate 9 and then move it out of the reaction chamber, and then use the suction cup to suck the substrate from the back of the substrate 10 After 10 seconds, the substrate 10 is removed from the reaction chamber. After the substrate 10 is removed from the reaction chamber, the substrate 10 is turned over so that the processed surface of the substrate 10 faces upward and then placed on the corresponding fixing rack. This process of repeatedly sucking, moving, and flipping is very complicated and cannot be completed using low-cost robotic arms. It is often completed manually. This will cause a large amount of particles to be adsorbed to the substrate during the substrate transfer process, eventually causing the flip-chip substrate to react. The advantage of less particulate matter brought by the cavity is greatly reduced.

Based on the technical problems disclosed above, the inventor proposed a new type of substrate tray structure. The invention can effectively solve the problem of difficulty in loading/unloading substrates in a flip-chip substrate tray. To this end, the inventor proposed an improved embodiment. Figures 2a and 2b are side cross-sectional views and top views of a substrate carrier ring element used in a flip-chip MOCVD reactor. This embodiment includes a carrier ring 182, and a plurality of substrate supporting claws 188 are provided inside the carrier ring 182, and the substrate supporting claws 188 are used to support the substrate W. The substrate support claw 188 includes a fixing section 188a for being fixed to the carrier ring 182, and a horizontal support section 188b. There is also a transition section between the two, so that the height of the horizontal support section 188b is is lower than the fixed section 188a. The outer side of the carrier ring 182 also includes a set of carrier ring support claws 189 evenly distributed on the circumference. The inner end of the carrier ring support claws 189 is fixed on the carrier ring 182, and the outer end is used to be set up in the support cavity opened on the inner wall of the substrate tray. . Figure 2b is a top view of the carrier ring element when the substrate is placed on the carrier ring 182. At least one of the carrier ring supporting claws 189, the carrier ring 182 and the substrate supporting claws 188 is made of ceramic material with low thermal conductivity, and other components may be made of high thermal conductive materials. Optimally, the substrate supporting claws 188 are made of low thermal conductivity materials such as quartz, and the remaining parts can be made of graphite and silicon carbide. Typically, the substrate is made of graphite and coated with a silicon carbide coating on the outer surface.

Figure 3a shows a bottom view of the substrate tray 8 after the carrier ring element has installed the substrate into the internal cavity of the substrate tray. The inner wall of the substrate tray 8 is provided with a plurality of openings corresponding to the carrier ring support claws 189. 180 as the lifting chamber. The opening 180 in the substrate tray 8 communicates with an adjacent transfer chamber 181 and a support chamber 183 . The bottom of the transfer chamber 181 includes a bottom surface 181a, the height of which is greater than the height of the substrate tray bottom surface 80. The bottom surface 183a of the support chamber 183 is used to support the carrier ring support claw 189 on the carrier ring element. The height of the bottom surface 183a of the support chamber 183 is lower than that of the transfer chamber. The height of the bottom surface 181a of 181 is higher than the height of the bottom surface 80 of the substrate tray. During the execution of the MOCVD process, the substrate to be processed first needs to be placed on the substrate supporting claws 188 of the ring-carrying element so that the processing area of the substrate faces downward. Then, the carrier ring is transferred to the bottom of the substrate tray through the robot arm, so that the carrier ring support claw 189 is opposite to the opening 180 on the bottom surface 80 of the substrate tray, and then the carrier ring position is lifted through the robot arm, so that the height of the carrier ring support claw 189 is high. at the height of the bottom surface 181a of the transfer chamber 181, and then the transfer head on the robot arm rotates or the substrate tray 8 rotates to cause the carrier ring support claw 189 to rotate in the circumferential direction across the transfer chamber 181 and enter the support chamber 183, and finally the robot arm moves toward The downward movement causes the ring-carrying support claws 189 on the ring-carrying element to drop to the bottom surface 183a of the support cavity 183, thereby realizing a method of loading substrates onto the substrate tray from below. The bottom surface 181a of the transfer chamber 181 is higher than the bottom surface 183a of the support chamber 183 so that the ring support claws 189 will not slide during the rotation of the substrate tray. The lateral width of the transfer chamber 181 can be very small, as long as it can prevent the ring support claws from sliding. The object of the present invention can be achieved by moving 189 horizontally.

Figure 3b is a cross-sectional view at the point On the bottom surface 183a, the horizontal support section 188b of the substrate support claw 188 is located below the substrate tray bottom surface 80, so that the upper surface of the horizontal support section 188b, that is, the substrate processing surface, is substantially flush with the substrate tray bottom surface 80.

Figure 3c is a cross-sectional view at Y in Figure 3a, in which the bottom surface of the inner wall of the substrate tray is provided with a plurality of openings 180 penetrating the bottom surface 80 of the substrate tray, a support cavity 183 and a transfer cavity 181. The inner side of the side wall above the support cavity 183 also includes a step portion for placing the heat diffusion plate 9 . Due to the structure of the substrate tray 8 of the present invention, substrates are loaded/unloaded through the opening 180 at the bottom of the substrate tray 8, so the top thermal diffusion plate 9 can be fixed to the substrate tray 8, or the thermal diffusion plate 9 Integrated with the top of the substrate tray 8 and manufactured as one component, or the size of the step portion of the thermal diffusion plate 9 and the substrate tray 8 can have a larger design space, and there is no need to consider frequent removal of the thermal diffusion plate 9 and the substrate below. The piece needs to pass through the space surrounded by the above-mentioned step part. The thermal diffusion plate 9 can also be composed of multiple parts as shown in Figure 3c, in which the thermal diffusion plate 9 is located at the peripheral annular thermal diffusion plate 9a and the circular thermal diffusion plate 9b erected on the annular portion. The area ratio and material composition of the annular thermal diffusion plate 9a9a and the circular thermal diffusion plate 9b can be optimized and selected according to the process requirements. For example, when the first process is executed, the central circular thermal diffusion plate 9b has the first thermal conductivity. In the second process, a different temperature distribution is required, so the circular heat diffusion plate 9b with another thermal conductivity can be replaced.

When the substrate needs to be unloaded to complete the MOCVD process, the opposite operation can be performed: extend the robotic arm under the carrier ring in the reaction chamber, lift the robotic arm to raise the carrier ring to a certain height, and select the height to avoid the carrier ring support claw 189 When colliding with the top surface of the support cavity 183, the bottom surface of the carrier ring support claw 189 must be higher than the height of the bottom surface of the transfer cavity 181. Then, one of the ring-carrying element or the substrate tray is rotated so that the two are relatively displaced, and then the ring-carrying support claw 189 moves to a position corresponding to the opening 180 . Finally, the mechanical arm is driven to descend, so that the ring-carrying element is separated from the substrate tray 8 . The carrier ring components are then transferred to other cavities of the thin film deposition system through the robotic arm, and then the Other mechanical devices turn the substrate over and separate the substrate from the carrier ring element. For example, the carrier ring and the substrate are transferred to the storage chamber or cooling chamber through a robotic arm, so that the temperature of the substrate is reduced to a temperature suitable for sucking by the suction cup, and then the suction cup is used to adsorb and fix the back of the substrate, and then the direction of the suction cup is flipped so that the processing side of the substrate faces superior. By adopting the structure of the substrate tray and the ring-carrying element of the present invention, the substrate can be removed from the reaction chamber under a high temperature state and a new substrate and ring-carrying element can be delivered. The processed high-temperature substrate can be placed in the reaction chamber. Waiting for cooling in the cooling chamber does not require waiting for cooling in the reaction chamber and then taking out the substrate through a complicated movement process, which improves the actual utilization of the reaction chamber.

In addition to being applicable to a reaction chamber with only one substrate tray, the present invention can also be applied to a reaction chamber with multiple substrate trays, but the above-mentioned mechanical arm or substrate tray rotation driving device needs to adapt to the structure of multiple substrate trays. For example, multiple substrate trays 8 are fixed on one substrate tray. Rotating the substrate tray causes the multiple substrate trays 8 to revolve. The robotic arm extends into the reaction chamber, and each time the aforementioned loading/unloading method is used to pick up and place a piece. The substrate and carrier ring components are then rotated so that the next substrate tray is close to the robotic arm and the next substrate and carrier ring component are removed. Finally, a robotic arm is used to process multiple substrates on a substrate carrier. Picking and placing tablets.

Among them, the carrier ring 182 needs to be made of a highly thermally conductive material such as graphite or silicon carbide, and the substrate support claw 188 needs to be made of a heat-insulating material. This design can ensure uniform uniformity on the carrier ring 182 during the MOCVD process. Temperature distribution, the edge of the substrate and the carrier ring 182 have a uniform radiation heat distribution, while reducing direct contact heat conduction between the substrate and the carrier ring 182, and ultimately obtaining the best substrate temperature distribution effect. Thermal insulation materials can be made of ceramic materials such as alumina, quartz, and sapphire. The thermal conductivity of alumina, quartz, and sapphire materials is only 4, 20, and 40W/m.k. The thermal conductivity of traditional substrate tray materials, graphite and silicon carbide materials, is The coefficient can reach 150-490W/m.k. By using thermal insulation materials, the heat conduction between the edge of the substrate and the substrate tray can be greatly reduced, thereby improving the temperature uniformity from the center to the edge of the substrate and improving the uniformity of the growth quality of the epitaxial material on the substrate. The carrier ring supporting claws 189 can be made of suitable materials to increase the temperature of the carrier ring 182 so that the temperatures of the carrier ring 182 and the substrate are close to each other, reducing the risk of Less lateral heat transfer. The substrate support claw 188, the carrier ring 182 and the carrier ring support claw 189 can be sintered as one integral part, or can be fixed by other methods, such as the fixed section 188a of the substrate support claw 188 being inserted into the inner wall of the carrier ring 182 The fixing holes provided on the carrier ring 189 can be fixed. Similarly, the carrier ring support claw 189 can also be mechanically fixed to the carrier ring 182 in this way.

Furthermore, in the present invention, the bottom surface of the carrier ring support claw 189 can be provided with a wedge-shaped groove/protrusion extending in the radial direction to match the protrusion/groove of the bottom surface 183a of the support cavity 183 in the substrate tray, wherein the groove The radial arrangement enables the ring support claws 189 to automatically align themselves when placed downwards, and the ring support claws 189 will not slip and move when the substrate tray is accelerating or decelerating. When the carrier ring support claw 189 is provided with a fixed mounting surface, the above-mentioned transfer cavity 181 can also be omitted, and the support cavity 183 is directly connected to the opening 180. Such a design can further simplify the structure of the substrate tray.

The bottom surface of the carrier ring 182 can also be provided with a plurality of convex portions or recessed portions used to cooperate with the robot arm support head, so that the two surfaces can be accurately positioned when combined with each other, and avoid slipping during horizontal movement.

In the present invention, the optimal requirement between the ring supporting claws 189 and the substrate supporting claws 188 is to be alternately staggered, so that the heat introduced by the ring supporting claws 189 from the bottom surface of the support cavity 183 will arrive via a longer path. The substrate supporting claws 188 prevent the temperature of the substrate around the substrate supporting claws 188 from being too high. The cross section of the substrate supporting claw 188 may be polygonal, such as a triangle, in which the upper surface of the substrate supporting claw 188 is a convex prism, so that the contact surface between the substrate supporting claw 188 and the substrate is a line contact. , minimizing the heat conduction.

Although the present invention is disclosed as above, the present invention is not limited thereto. Anyone with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be based on the scope defined by the patent application scope.

182:Carrying Ring

188:Substrate support claw

189:Carrying ring support claw

Claims (5)

A ring-carrying element for supporting a substrate, wherein: the ring-carrying element includes: a ring; a plurality of ring-carrying support claws spaced apart from each other on the ring; one end of each ring-carrying claw is fixed to The other end of the carrier ring extends to the outside of the carrier ring; and a plurality of substrate support claws are spaced apart from each other on the carrier ring. One end of each substrate support claw is fixed to the carrier ring, and the other end is toward the carrier ring. The inner side of the carrier ring extends to support the substrate; at least one of the carrier ring, the carrier ring support claw, and the substrate support claw is made of a low thermal conductivity material with a thermal conductivity of less than or equal to 40W/m.k, and the other parts are made of Made of high thermal conductivity material with thermal conductivity greater than or equal to 150W/m.k. The carrier ring element of claim 1, wherein the substrate supporting claw is made of low thermal conductivity material. The carrier ring element of claim 1, wherein the substrate support claw includes a fixed section fixed to the carrier ring, and a horizontal support section for supporting the substrate, connected between the fixed section and the horizontal support section a transition section, wherein the transition section extends downwardly from the fixed section. The carrier ring element of claim 1, wherein the top section of the horizontal support section is tapered with a smaller top and a larger bottom, so that the contact surface between the top of the horizontal support section and the substrate is minimized. The ring-carrying element according to claim 1, wherein the bottom surface of the ring-carrying supporting claw includes a convex portion or a recessed portion to prevent the ring-carrying supporting claw from sliding.