Epitaxial growth apparatus and multi-layer gas supply module used therein

Abstract

To provide an epitaxial growth apparatus which forms the uniform gas distribution in the entire region of a large-area substrate to uniformly grow an epitaxial layer and a gas supply module therefor.SOLUTION: An apparatus includes: a reaction chamber; a susceptor 150 positioned in the reaction chamber and configured to seat a wafer W thereon; and a multi-layer gas supply module 200 configured to supply a gas to the reaction chamber to form an epitaxial layer on the wafer, wherein the multi-layer gas supply module includes an injector 210 including ports 211-213 of a plurality of layers, each of which discharges a different gas for each layer, the ports of each layer including a center port 216 corresponding to a central region of the wafer, and a pair of edge ports 217 corresponding to both edge regions of the wafer, and the injector further includes a flow distribution unit configured to distribute gas flows input to the center port and the edge port among the ports of each layer independently from each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an epitaxial growth apparatus and its gas supply module used to grow epitaxial layers on wafers. [Background technology]

[0002] Generally, epitaxial growth is the process of depositing new layers on a seed wafer using a single-crystal growth method while maintaining the lattice direction. Epitaxial growth requires a growth device that applies gas to the wafer.

[0003] The gas supply system of an epitaxial growth apparatus is composed of an injector, a baffle, an insert, and a liner, according to the procedure in which gas is injected into the chamber from a gas tank.

[0004] The key to gas supply is to achieve uniform gas distribution within the chamber. This allows for a uniform epitaxial layer thickness to be achieved on large-area substrates (substrates with a size of 6 inches or larger). The uniformity of the epitaxial layer is preferably 1% or less.

[0005] However, in conventional gas supply systems, multiple gases are injected into the chamber through a single inlet, making it difficult to achieve uniform gas distribution. This is especially difficult for large-area substrates. Furthermore, gas distribution is not uniform between the center and edge of the substrate. This results in thickness non-uniformity of the grown epitaxial layer of 5% or more. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an epitaxial growth apparatus and a multi-layer gas supply module used therein, which can form a uniform gas distribution over the entire area of ​​a substrate in order to grow a uniform epitaxial layer on the large-area substrate. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided an epitaxial growth apparatus including: a reaction chamber; a susceptor positioned within the reaction chamber and configured to seat a wafer; and a multi-layer gas supply module configured to supply gas to the reaction chamber to form an epitaxial layer on the wafer, the multi-layer gas supply module having a plurality of layers of ports for discharging different gases for different layers, each of the plurality of ports including a center port corresponding to a central region of the wafer, a pair of edge ports corresponding to edge regions on both sides of the wafer, and a pair of middle ports respectively disposed between the center port and the pair of edge ports; an injector; a single inlet line through which the gas is input from a source module; a plurality of branch lines branching from the single inlet line and directly connected to each of the ports; and a mass flow controller connected to each of the ports. a flow rate distribution unit including a flow controller and configured to distribute the gas independently to the ports; and a baffle located in front of the injector and including passage holes for passing the gas discharged from the ports, wherein the passage holes corresponding to ports in at least one layer of the multiple layers of ports are formed in different shapes.

[0008] Here, the center port, the middle port, and the edge port may have the same width.

[0009] Here, the ports of the multiple layers may include a port of a first layer that discharges a raw material gas for forming the epitaxial layer; and a port of a second layer that is located above the port of the first layer and discharges a blocking gas that blocks upward diffusion of the raw material gas.

[0010] Here, the ports in the plurality of layers may further include a third port disposed below the first port and configured to discharge a purge gas for purifying by-products generated during growth of the epitaxial layer.

[0011] Here, the passage holes include passage holes in a first layer corresponding to the ports in the first layer; passage holes in a second layer corresponding to the ports in the second layer; and passage holes in a third layer corresponding to the ports in the third layer, and the passage holes in the second layer may have a cylindrical shape, and the passage holes in the first layer and the third layer may have a mixed cylindrical and conical shape.

[0012] Here, the through holes of the first layer and the through holes of the third layer corresponding to the center port may have a cylindrical shape, the through holes of the first layer and the through holes of the third layer corresponding to the edge port may have a cone shape, and the through holes of the third layer may have a smaller cross-sectional area than the through holes of the first layer.

[0013] According to another aspect of the present invention, a supply control module for an epitaxial growth apparatus may include a multi-layer gas supply module for supplying gases to be introduced into a reaction chamber of the epitaxial growth apparatus, the multi-layer gas supply module including a plurality of ports for discharging different gases to different layers, each of the plurality of ports including a center port corresponding to a central region of a wafer, a pair of edge ports corresponding to edge regions on both sides of the wafer, and a pair of middle ports respectively disposed between the center port and the pair of edge ports; a flow distribution unit including a single inlet line through which the gas is input from a source module that generates the gas, a plurality of branch lines branching from the single inlet line and directly connected to each of the ports, and mass flow controllers connected to each of the ports, and configured to independently distribute the gas to the ports; and a baffle located in front of the injector and including passage holes for passing gases discharged from the ports, wherein the passage holes corresponding to ports of at least one layer of the plurality of ports among the passage holes have different shapes.

[0014] Here, the center port, the middle port, and the edge port may have the same width.

[0015] Here, the ports in the multiple layers may include a port in a first layer that discharges a raw material gas for forming an epitaxial layer; and a port in a second layer that is located above the port in the first layer and discharges a blocking gas that blocks the upward diffusion of the raw material gas.

[0016] Here, the passage holes include passage holes of a first layer corresponding to the ports of the first layer; and passage holes of a second layer corresponding to the ports of the second layer, and the passage holes of the second layer may have a cylindrical shape, and the passage holes of the first layer may be a mixture of cylindrical and conical shapes.

[0017] According to another aspect of the present invention, an epitaxial growth apparatus includes a reaction chamber; a susceptor located within the reaction chamber and configured to seat a wafer; and a multi-layer gas supply module configured to supply gas to the reaction chamber to form an epitaxial layer on the wafer, the multi-layer gas supply module including a plurality of ports for discharging different gases for each layer, each port of the plurality of ports including a center port corresponding to a central region of the wafer and a pair of edge ports corresponding to edge regions on both sides of the wafer; and a flow rate distribution unit configured to independently distribute gas flow rates input to the center port and the edge ports of the ports of each layer.

[0018] Here, the ports of each layer of the multiple layers of ports may further include a pair of middle ports respectively disposed between the center port and the pair of edge ports, and the flow rate distribution unit may be configured to distribute the gas flow rate input to the middle ports independently of the gas flow rates input to the center port and the edge ports. [Effects of the Invention]

[0019] According to the epitaxial growth apparatus and multi-layer gas supply module used therein configured as described above, the multi-layer gas supply module for supplying gas to a wafer seated on a susceptor in a reaction chamber has multiple layers of ports that output different gases for each layer. The ports for each layer are provided with injectors that independently distribute the gas flow rate to each port, and each port has a center port and a pair of edge ports located on either side of the center port. This allows for uniform gas distribution across the entire area of ​​a large-area substrate, thereby enabling uniform growth of an epitaxial layer. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a conceptual diagram of an epitaxial growth apparatus according to an embodiment of the present invention; [Figure 2]FIG. 2 is a perspective view showing a partial configuration of the epitaxial growth apparatus of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view showing the injector-related configuration of FIG. 2. [Figure 4] FIG. 3 is a front view of the baffle and injector of FIG. 2. [Figure 5] 5 is a cross-sectional view showing the shape of the center port and the corresponding through hole of FIG. 4. FIG. [Figure 6] 5 is a cross-sectional view showing the shape of the middle port and the corresponding through hole of FIG. 4. FIG. [Figure 7] 5 is a cross-sectional view showing the shape of the edge port and the corresponding through hole of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an epitaxial growth apparatus and a multi-layer gas supply module used therein according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this specification, the same or similar reference numerals are used to refer to the same or similar components even in different embodiments, and the description thereof supersedes the first description.

[0022] FIG. 1 is a conceptual diagram of an epitaxial growth apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a partial configuration of the epitaxial growth apparatus of FIG.

[0023] Referring to this figure, an epitaxial growth apparatus 100 includes a reaction chamber 110 , a susceptor 150 , a multi-layer gas supply module 200 , and a source module 300 .

[0024] The reaction chamber 110 has a reaction space where an epitaxial reaction occurs. The reaction space is simply represented by a rectangular box in the drawings, but may specifically be a stack of a lower housing (not shown) and an upper housing (not shown). The upper and lower housings may be made of a transparent material such as quartz glass. Gas may be supplied to the left side of the reaction space by a multi-layer gas supply module 200, and gas may be exhausted to the right side of the reaction space.

[0025] The susceptor 150 is located in the reaction space and is a target on which the wafer W is fixed. The susceptor 150 may have a flat disk shape. The susceptor 150 may be made of carbon graphite or a material in which carbon graphite is coated with silicon carbide. The wafer W has a size of 6 inches or 8 inches or more and is therefore classified as a large-area wafer.

[0026] The multi-layer gas supply module 200 is configured to provide gases and regulate the flow of the gases into the reaction chamber 110. The multi-layer gas supply module 200 may include an injector 210, a flow rate distribution unit 230, a baffle 250, an insert 270, and a liner 290.

[0027] The injector 210 is configured to discharge the gas input from the source module 300 in a direction toward the reaction chamber 110. The injector 210 may include multiple ports 211, 212, and 213 that output different gases for different layers.

[0028] The port 211 of the first layer discharges a source gas for forming an epitaxial layer on the wafer W. The port 211 of the first layer may be located 0.5 to 1 mm above the surface of the wafer W. The gas injected into the chamber 110 through the port 211 of the first layer is adsorbed onto the surface of the wafer W by the heat of the wafer W. For example, when forming a silicon carbide epitaxial layer, the source gas may be silicon or carbon. These are discharged from the port 211 of the first layer together with hydrogen gas as a carrier gas, and nitrogen and aluminum may also be discharged.

[0029] The silicon source gas may be any silicon-containing gas, such as SiH4, SiHCl3, SiHCl2, SiCl4, or Si2H6. The carbon source gas may be a hydrocarbon gas containing carbon and hydrogen, such as C2H2, C2H4, CH4, C2H5OH, CH3OH, or C3H8. Nitrogen is used as an impurity for N-type, and aluminum is used for P-type. The impurity gas is discharged from the port 211 of the first layer simultaneously with the source gas or with a slight time lag. In addition, the port 211 of the first layer may also discharge gases necessary for SiC growth, such as HCl, N2, Al, or Ar.

[0030] The port 212 of the second layer is located above the port 211 of the first layer. The port 212 of the second layer discharges a blocking gas that prevents the source gas from dispersing upward. The blocking gas may be, for example, hydrogen gas in a silicon carbide epitaxial layer growth process. The hydrogen gas forms a hydrogen blocking film (hydrogen dome) above the wafer W. The gas discharged from the port 211 of the first layer is blocked by the hydrogen blocking film and does not diffuse into the upper space of the chamber 110. The hydrogen blocking film allows the source gas to act only on the wafer W, thereby maintaining a high gas concentration of the source gas acting on the wafer W. This allows the growth rate of the silicon carbide epitaxial layer to be 25 μm per minute or more. The port 212 of the second layer may be located 1.5 to 3 mm above the surface of the wafer W. In this case, the discharged hydrogen gas is not adsorbed on the surface of the wafer W, effectively forming a blocking film above the wafer W.

[0031] The port 213 of the third layer is disposed below the port 211 of the first layer. The port 213 of the third layer discharges a purge gas for purifying by-products generated during the growth of an epitaxial layer. The purge gas may be argon gas. The purge gas may be introduced at the beginning of the end of the growth of the epitaxial layer. The port 213 of the third layer may be disposed 0.2 to 0.4 mm above the surface of the wafer W.

[0032] Port 213 in the third layer is for hydrogen and CH X Hydrocarbon gas (mainly C3H8) can also be discharged. When growing P-type, N-type, or semi-insulating SiC, the process variable that must be considered is the C / S1 ratio. If the ratio of silicon to hydrocarbon discharged from port 211 of the first layer is not appropriate, the C / S1 ratio can be adjusted by discharging additional carbon gas from port 213 of the third layer. By adjusting the C / S1 ratio between 0.6 and 2.7, P-type, N-type, and semi-insulating SiC can be grown according to the application. Here, hydrogen plays the role of transporting the carbon gas.

[0033] In the first layer port 211 to the third layer port 213, the ports of each layer are divided into ports 216, 217, and 218 corresponding to the areas of the wafer W. This will be described with reference to FIG.

[0034] The flow rate distribution unit 230 distributes the gas flow rate input to the injector 210 to each port of the injector 210. The gas flow rates for each region may be independent of each other, which will also be described in detail with reference to FIG.

[0035] 1 and 2, the baffle 250 has through holes 251, 253, and 255 through which gas input via the injector 210 passes. The shapes of the through holes 251, 253, and 255 may vary depending on the ports 211, 212, 213 / 216, 217, and 218 of the injector 210. This will be explained in more detail with reference to FIGS. 4 to 7.

[0036] 1 and 2, insert 270 is disposed between baffle 250 and liner 290 and has a configuration that guides gas that has passed through baffle 250 to liner 290. Insert 270 may also have multiple regions that allow gas to pass through.

[0037] The liner 290 surrounds the susceptor 150 and guides the gas to flow toward the wafer W. To this end, the liner 290 may have a generally ring-like shape. One side of the liner 290 may have a portion for discharging gas toward the wafer W, and the other side may have a portion for discharging gas away from the wafer W.

[0038] The source module 300 may be a gas tank that stores gases that must be supplied to the reaction chamber 110, or may be an intermediate distributor connected thereto.

[0039] The injector 210 and the flow rate distribution unit 230 will be described below with reference to Fig. 3. Fig. 3 is a cross-sectional view showing the injector-related configuration of Fig. 2.

[0040] With additional reference to this figure, the injector 210, and specifically its individual layer ports 211, 212, 213, includes a center port 216, an edge port 217, and a middle port 218.

[0041] The center port 216 is located corresponding to the central region of the wafer W. The edge ports 217 may be provided in pairs corresponding to the edge regions on both sides of the wafer W. The middle port 218 may be located between the center port 216 and the edge port 217. The middle ports 218 may also be provided in pairs, located on both the left and right sides of the center port 216. The left and right portions of the center port 216, the pair of edge ports 217, and the pair of middle ports 218 may be symmetrical with respect to an imaginary line L passing through the center of the center port 216. The center port 216, the edge ports 217, and the middle ports 218 may have the same width (length in the left-right direction in the drawing) or volume. Furthermore, the wafer W may be configured with only the center port 216 and the pair of edge ports 217, without the middle port 218. In this case, the areas of the center port 216 and the edge ports 217 may be large enough to cover the middle port 218.

[0042] The flow rate distribution unit 230 has an inlet line 231 and a branch line 235. The inlet line 231 is a single line that communicates with the source module 300 and through which gas is input. On the other hand, the branch line 235 branches off from the inlet line 231 and is connected to each of the ports 211, 212, 213 / 216, 217, and 218.

[0043] The flow rate distribution unit 230 may include a mass flow controller (not shown) connected to each of the ports 211, 212, 213 / 216, 217, and 218. The gas input amount to each port 211, 212, 213 / 216, 217, and 218 can be independently distributed by setting each of the mass flow controllers. For example, the gas input amount to the center port 216 may be the lowest, and the gas input amount to the pair of edge ports 217 may be the highest. The gas input amount to the pair of middle ports 218 may be an intermediate level between the pair of edge ports 217 and the pair of middle ports 218. The flow rate distribution unit 230 may also distribute gas so that the input amounts from the pair of edge ports 217 and the pair of middle ports 218 are symmetrical with respect to the center port 216.

[0044] Next, the baffle 250, which allows the gases separated into a plurality of regions and discharged through the injector 210 to pass toward the reaction chamber 110, will be described with reference to FIGS.

[0045] First, FIG. 4 is a front view of the baffle 250 and the injector 210 shown in FIG.

[0046] Referring to this figure, gas discharged from each of the ports 211 , 212 , 213 / 216 , 217 , and 218 passes through the passage holes 251 , 253 , and 255 of the baffle 250 .

[0047] The through holes 251, 253, and 255 include a first layer through hole 251, a second layer through hole 253, and a third layer through hole 255. The first layer through hole 251 is located corresponding to the first layer port 211. The second layer through hole 253 is located corresponding to the second layer port 212, and the third layer through hole 255 is located corresponding to the third layer port 213.

[0048] The second layer of passing holes 253 have uniform sizes at positions corresponding to the center port 216, the middle port 218, and the edge port 217. In contrast, the first layer of passing holes 251 and the third layer of passing holes 255 may have smaller sizes from those corresponding to the center port 216 to those corresponding to the edge port 217. This configuration allows a large amount of blocking gas passing through the second layer of passing holes 253 to be injected into the chamber 110 regardless of the region, and allows the source gas and purge gas passing through the first layer of passing holes 251 and the third layer of passing holes 255 to be injected at different rates depending on the region of the wafer W. Specifically, because the gas flow rate is slower at the edge of the wafer W than at the center, the size of the passing holes can be reduced from the center port 216 to the positions corresponding to the edge port 217 to compensate for the flow rate of the gas passing therethrough.

[0049] Next, Figure 5 is a cross-sectional view showing the shape of the center port and corresponding pass-through hole of Figure 4, Figure 6 is a cross-sectional view showing the shape of the middle port and corresponding pass-through hole of Figure 4, and Figure 7 is a cross-sectional view showing the shape of the edge port and corresponding pass-through hole of Figure 4.

[0050] Referring to this figure, in all of the ports 211 on the first layer to the ports 213 on the third layer, the center port 216, middle port 218, and edge port 217 may have uniform sizes. In addition, the passing holes 253 on the second layer corresponding to the center port 216, middle port 218, and edge port 217 may also have the same sizes. Because they have a cylindrical shape, there is no change in width (diameter) from their input end to their output end.

[0051] The first layer of through holes 251 and the third layer of through holes 255 are a mixture of cylindrical and cone-shaped through holes. For example, the through holes 251 and 255 corresponding to the center port 216 are cylindrical, while the through holes 251 and 255 corresponding to the edge port 217 and the middle port 218 may be cone-shaped.

[0052] The width of the passage holes 251, 253, and 255 corresponding to the center port 216 decreases in the direction from the passage hole 253 in the second layer, through the passage hole 251 in the first layer, to the passage hole 255 in the third layer. This relationship also applies to the passage holes 251, 253, and 255 corresponding to the middle port 218 and the passage holes 251, 253, and 255 corresponding to the edge port 217. This relationship indicates that the velocity of the injected gas increases as the height approaches the wafer W.

[0053] The epitaxial growth apparatus and the multi-layer gas supply module used therein are not limited to the configurations and operation methods of the above-described embodiments, and various modifications can be made by selectively combining all or part of the embodiments. [Explanation of symbols]

[0054] 100 Epitaxial growth equipment 110 Reaction Chamber 150 susceptor 200 Multi-layer Gas Supply Module 210 Injector 230 Flow Distribution Unit 250 Baffle 270 insert 290 Liner

Claims

1. A reaction chamber; a susceptor positioned within the reaction chamber and configured to seat a wafer; and a multi-layer gas supply module configured to supply gas to the reaction chamber to form an epitaxial layer on the wafer; Including, The multi-layer gas supply module comprises: an injector having a plurality of layers of ports for discharging different gases for different layers, the plurality of layers of ports each including a center port corresponding to a central region of the wafer, a pair of edge ports corresponding to edge regions on both sides of the wafer, and a pair of middle ports respectively disposed between the center port and the pair of edge ports; a mass flow distribution unit including a single inlet line through which the gas is input from a source module, a plurality of branch lines branching from the single inlet line and directly connected to each of the ports, and a mass flow controller connected to each of the ports, configured to distribute the gas independently to the ports; and a baffle including a passage hole located in front of the injector for passing gas discharged from the port, the passage hole corresponding to at least one port of the plurality of layers of ports among the passage holes being formed to have different shapes; Including, The multi-layer port includes: a first layer port for discharging a source gas for forming the epitaxial layer; and a second layer port located above the first layer port and discharging a blocking gas that blocks upward diffusion of the source gas.

2. The center port, the middle port, and the edge port are 2. The epitaxial growth apparatus of claim 1, wherein the widths of the epitaxial growth apparatus are the same as each other.

3. The multi-layer port includes:

2. The epitaxial growth apparatus according to claim 1, further comprising a third layer port disposed below the first layer port for discharging a purge gas for purifying by-products generated during growth of the epitaxial layer.

4. The passage hole is a first layer through hole corresponding to said first layer port; a second layer through hole corresponding to the second layer port; and a third layer through hole corresponding to said third layer port; Including, The second layer of through holes is It has a cylindrical shape, The first layer through hole and the third layer through hole are 4. The epitaxial growth apparatus according to claim 3, wherein cylindrical and conical shapes are mixed.

5. the through hole of the first layer and the through hole of the third layer corresponding to the center port have a cylindrical shape, 5. The epitaxial growth apparatus according to claim 4, wherein the through holes of the first layer and the through holes of the third layer corresponding to the edge ports have a cone shape.

6. The third layer of through holes is 5. The epitaxial growth apparatus of claim 4, wherein the first layer has a cross-sectional area smaller than that of the via holes.

7. 1. A multi-layer gas supply module for supplying gases to be input into a reaction chamber of an epitaxial growth apparatus, comprising: an injector having a plurality of layers of ports for discharging different gases for different layers, the plurality of layers of ports each including a center port corresponding to a central region of a wafer, a pair of edge ports corresponding to edge regions on both sides of the wafer, and a pair of middle ports respectively disposed between the center port and the pair of edge ports; a single inlet line through which the gas is input from a source module that generates the gas; a plurality of branch lines branching from the single inlet line and directly connected to each of the ports; and a mass flow controller connected to each of the ports, the mass flow distribution unit being configured to independently distribute the gas to the ports; and a baffle including a passage hole located in front of the injector for passing gas discharged from the port, the passage holes corresponding to at least one port of the plurality of layers of ports being formed to have different shapes; Including, The multi-layer port includes: A port in the first layer for discharging a source gas for forming an epitaxial layer; and a second layer port located above the first layer port and discharging a blocking gas that blocks upward diffusion of the source gas.

8. The center port, the middle port, and the edge port are 8. The multi-layer gas supply module for an epitaxial growth apparatus according to claim 7, having the same width as each other.

9. The passage hole is a first layer through hole corresponding to the first layer port; and a second layer through hole corresponding to the second layer port; The second layer of through holes is It has a cylindrical shape, The first layer of through holes is 8. The multi-layer gas supply module for an epitaxial growth apparatus according to claim 7, wherein the cylindrical and conical shapes are mixed.

10. A reaction chamber; a susceptor positioned within the reaction chamber and configured to seat a wafer; and a multi-layer gas supply module configured to supply gas to the reaction chamber to form an epitaxial layer on the wafer; Including, The multi-layer gas supply module comprises: an injector having multiple layers of ports for discharging different gases for different layers, each layer of the ports having a center port corresponding to a central region of the wafer and a pair of edge ports corresponding to edge regions on both sides of the wafer; and a flow rate distribution unit configured to distribute gas flow rates input to the center port and the edge port among the ports of each layer independently of each other; Including, The multi-layer port includes: a first layer port for discharging a source gas for forming the epitaxial layer; and a second layer port located above the first layer port and discharging a blocking gas that blocks upward diffusion of the source gas.

11. The ports of each layer among the multiple layers are: a pair of middle ports respectively disposed between the center port and the pair of edge ports; The flow rate distribution unit includes:

11. The epitaxial growth apparatus according to claim 10, wherein the gas flow rate input to the middle port is allocated independently of the gas flow rates input to the center port and the edge port.

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