TW449789B - Furnace for semiconductor manufacture - Google Patents

Abstract

This invention provides a furnace for semiconductor manufacture with two outer tubes. The furnace consists of a plate, a quartz outer tube, a heat buffer layer, a silicon carbide outer tube, a silicon carbide inner tube and a wafer boat in the order from outside to inside arranged on the plate. The quartz outer tube is used to isolate the furnace apparatus from the outside ambience, the employment of the silicon carbide outer tube is to prevent particle from remaining on the inner surface of the quartz outer tube and the heat buffer layer is capable of reducing the thermal stress between two outer tubes and preventing gas leakage from the silicon carbide inner tube.

Description

449 789 V. Description of the invention U) Field of the invention The present invention provides a semiconductor furnace tube device having a double-layer outer tube, in particular a type having a quartz outer tube and a silicon carbide, SiC) semiconductor furnace tube device with double outer tube outer tube. Background Description Chemical vapor deposition (CVD) is currently the most important method of thin film deposition in semiconductor processes. A typical CVD system includes a reactor, a set of gas delivery systems, an exhaust system, and a process control system. CVD reactors (reaction chamber / reactor) have many types according to their different applications and designs, such as atmospheric pressure (AP), low pressure (LP) and plasma (PE) reactors. With the advancement of the semiconductor process, in order to increase throughput, most of the batch process design is used today, so that the furnace-type reactor has become the most commonly used hot wall. A hot wal 1 reactor is used to perform the deposition process of polysilicon, siiiC0I1 dioxide, and silicon nitride. Please refer to Fig. 1 '-a schematic diagram of a conventional semiconductor furnace tube device 10. The conventional semiconductor furnace tube device 10 mainly includes an intake chamber 12, a stone 449 789, and a description of the invention _ (2)

British outer tube 16, a carbonized, inner tube 18 (stone tube) and a boat (22). The air inlet chamber 12 is provided at the bottom of the furnace tube device 10 so that the process gas can be sent into the furnace tube device 10 from the inlet of the air inlet chamber 12. The top of the air intake trap 12 is composed of a flat plate 14, and the inner tube 18 of the broken fossil evening tube is placed on the flat plate 14. The quartz outer tube 16 is provided at the outermost layer 'of the furnace tube device 10 and is sealed with a ring-shaped gasket (0-r i n g) 2 6' to avoid leakage of process gas. In addition, the wafer boat 2 2 within the carbonized inner tube 18 is a metallurgical tool used to insert or remove batches (about 25 to 200 pieces) of wafers in the furnace during the deposition reaction process. High-purity quartz or processed carbonite (S i C) is made 'to reduce particulate pollution (partic 1e). It is conventionally known that in the process of depositing polycrystalline silicon, silanium (Si lane) (SiH4) is decomposed by heating and then introduced into a furnace tube device 10. Silane gas flows along the direction of the airflow 28 in Figure 1, and enters the compound silicon inner tube 18 through the top of the air intake chamber 12 to make the wafers (not shown) placed on the wafer boat 2 2 uniform. The ground is in an atmosphere of silicon methane. The process gas will then flow to the top of the silicon carbide inner tube 18, then flow out through the top opening of the silicon carbide inner tube 18, and flow down the gap between the silicon carbide inner tube 18 and the quartz outer tube 16. 8 Finally, the remaining process gas is extracted by an extraction device connected to the air outlet 24. During the chemical vapor deposition (CVD) process of polycrystalline silicon, the temperature at the time of the initial introduction of silicon methane is about 640 ° C, and then after repeated temperature rise and fall processes, it will eventually drop to about 30 ° C. . However, the conventional furnace tube device 10

Page 5 449789 ^ 49 78 9 _; _ 5. Description of the invention '(3) Use carbonized crushed and quartz as materials for the inner tube 18 and outer tube 16' Carbonite thermal expansion coefficient at 6 0 (TC (CTE) is about 4.19 X 1 0 -6 / ° C, the thermal expansion coefficient of quartz is about 0.5 5 to 0.7 (x 1 0 -6 wide C), and the thermal expansion coefficient of polycrystalline silicon is about 2 Between 5 and 4.5 (X 1 0 -6 / ° c), the thermal expansion coefficient of quartz is very large, and it is closer to the thermal expansion coefficient of silicon carbide at 60 OeC. Therefore, during the aforementioned temperature reduction process, The quartz outer tube 16 will cause tensile stress (ie, tension) on the polycrystalline silicon film attached to the tube wall. However, the tensile stress of polycrystalline silicon is only 497 0 Psi ', which is much smaller than the compression stress (compression) 7500 Psi, so it will cause polycrystalline silicon film. The occurrence of spalling makes subsequent polycrystalline silicon deposited on the crack openings easy to form a considerable number of polycrystalline dream particles. That is, the polycrystalline silicon film attached to the quartz outer tube 16 will be affected by the furnace tube device 10 Heating, cooling, and continuous peeling, which directly causes particles on the wafer surface particle) pollution, or the cleanliness of the wafer 'surface and the furnace tube device 10 as the gas flow of the process gas circulates in the furnace tube device 10. In order to solve the particulate pollution that occurs in the furnace tube device 10 above, At present, the inner tube 18 and the crystal boat 22 have already adopted the thermal expansion coefficient U Huamiao as the production material. However, the outer tube 1δ:

The carbonized material is mainly because two problems cannot be made. The Θ dagger is a porous material. If the material of the outermost tube of carbide 3 is used, it will not be able to form a relatively closed hollow dagger:

Page 6 449789 V. Description of the invention (4) The inside of the pipe device 10 is completely isolated from the outside. During the deposition of polycrystalline silicon, the toxic silicon dioxide gas may leak out because of this, so it is possible to directly use silicon carbide as the material of the outer tube. On the other hand,

As far as I technology is concerned, it is not yet possible to make a single-piece silicon carbide outer tube. It can only be joined by several hollow ingot-like silicon carbides, but the tightness of the joint must not be able to achieve a completely sealed process gas. (2) The thermal conductivity of carbonized stone is about 36 W / m ° C, and the thermal conductivity of quartz is only 0.14 W / m ° C. Therefore, when using an annular gasket 26 to seal the outer tube, if silicon carbide is used as the material of the outer tube 16, it is easy for the thermal conductivity of the silicon carbide to be too good, so that the heat energy is quickly conducted from the main body of the outer tube 16 to the annular seal. The gasket 26 deteriorates and damages the ring-shaped gasket 26 and destroys the sealing vacuum degree of the furnace tube device 10. SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide a semiconductor furnace tube device having a quartz outer tube and a silicon carbide outer tube double-layer outer tube to solve the problems of the conventional technology. In a preferred embodiment of the present invention, the furnace tube includes a flat plate, and a quartz outer tube, a thermal buffer layer, a silicon carbide outer tube, a silicon carbide inner tube, and a wafer boat are sequentially arranged from the outside to the inside. On the tablet. The quartz outer tube is used to isolate the furnace tube device from the outside, the silicon carbide outer tube is used to prevent particles from remaining on the inner wall surface of the quartz outer tube, and the thermal buffer layer is used for 449789 V. Description of the invention ( 5) Reducing the thermal stress between the two outer tubes and avoiding the drag of the gas in the silicon carbide inner tube. The design of the present invention is to use a silicon carbide outer tube to avoid the generation of polycrystalline silicon particles to ensure the cleanliness of the wafer surface and the furnace tube device, thereby reducing the number of cleaning and purification of the furnace tube device. In addition, the thermal buffer layer formed by passing nitrogen gas between the double-layer outer tubes can not only slow down the thermal stress caused by the temperature difference between the silicon carbide outer tube and the quartz outer tube, but also avoid the silicon carbide inner tube. The intermediate process gas is leaked between the silicon carbide outer tube and the quartz outer tube. Detailed description of the invention Please refer to FIG. 2. FIG. 2 is a schematic diagram of a semiconductor furnace tube device 40 of the present invention. The furnace tube device 40 of the present invention mainly includes an air inlet chamber 42, a quartz outer tube 46, a carbonized petrified tube 50, a carbonized petrified tube 48, and a wafer boat 52. Located at the bottom of the furnace tube device 40, the process gas can be sent into the furnace tube device 40 from the inlet of the air inlet cabin 42. The 42th part of the air intake cabin is composed of a flat plate 4 4, and a silicon carbide inner tube 4 8 is placed on the flat plate 4 4. The wafer boat 5 2 within the silicon carbide inner tube 4 8 is a metallurgical tool used to insert or pull out batches (about 25 to 200 pieces) of wafers in the furnace during the deposition reaction process, usually with high purity. Made of quartz or processed silicon carbide (S i C) to reduce particulate contamination β

Page 8 4 49 78 9 V. Description of the invention (6) The quartz outer tube 46 is provided on the outermost layer of the furnace tube device 40, and is used to isolate the furnace tube device from the outside. A ring seal (0-ri ng ) 5 6 Seal to avoid leakage of process gas. The furnace tube device 40 of the present invention further includes a silicon carbide outer tube 50 disposed between the silicon carbide inner tube 48 and the quartz outer tube 46 to prevent polycrystalline silicon particles from remaining on the inner wall of the quartz outer tube 46. When the device of the present invention is used to perform the polycrystalline silicon deposition process, the silicon sintered (3) -18116, 3 丨 114) is first passed through the air inlet chamber 42 into the furnace tube device 40 for heating and dissociation. Since the top opening of the air intake chamber 4 2 is tightly connected to the bottom of the silicon carbide inner tube 4 8, the silicon gas burned in will enter the silicon carbide inner tube 4 6 along the flow direction 5 8 in FIG. 2. The wafers placed on the wafer boat 22 can be evenly placed in a silicon methane atmosphere. Then the process gas will flow to the top of the silicon carbide inner tube 48, and then flow out along the top opening, and flow down along the silicon carbide inner tube 48 and the silicon carbide outer tube 50. Finally, a gas extraction device (not shown) connected to the gas outlet 54 is used to extract the remaining process gas. The furnace tube device 40 of the present invention includes a thermal buffer layer 62 between the silicon carbide outer tube 50 and the quartz outer tube 46. The thermal buffer layer 62 is composed of a region filled with nitrogen gas, and the gas pressure in the region is greater than or equal to the pressure of the gas in the silicon carbide inner tube to form a gas barrier, so that the outer wall of the silicon carbide outer tube 50 The pressure of the gas (nitrogen) is greater than the pressure of the gas (silicon methane) on the inner wall, thereby preventing the process gas in the silicon carbide inner tube 48 from leaking to the carbon.

Page 9 i 449 789 V. Description of the invention (7) '' Between the silicon outer tube 50 and the quartz outer tube 46, and between the quartz outer tube 46; a polycrystalline silicon film is formed on the inner wall, and even the furnace tube device leaks out Other than 4 0. The output of the thermal buffer layer 62 can be connected to the same pumping device as the process gas to pump out nitrogen.丨.

I! In another embodiment of the present invention, the silicon carbide outer tube 50 and the quartz outer tube 46 may also be combined into a composite outer tube, that is, between the quartz outer tube 46 and the silicon carbide outer tube 50 (composite Middle layer of the outer tube) using a material that can reduce the thermal stress between the quartz outer tube 46 and the silicon carbide outer tube 50 to make the thermal buffer layer 62, or first coat the outer wall of the silicon carbide outer tube 50 After distributing a high-density material, it is combined with the quartz outer tube 4 6 to form a composite outer tube. The middle of the silicon carbide outer tube 50 and (::: quartz outer tube 4 6 is evacuated or filled with a gas as The thermal buffer layer 62 forms the composite outer tube. Because the thermal expansion coefficient (CTE) of the silicon carbide material is similar to that of polycrystalline silicon (at 60 ° C, the thermal expansion coefficient of silicon carbide is approximately 4.1 9χ 1 0 -6 / ° C, and the thermal expansion coefficient of polycrystalline silicon is about 2.5x 1 0 -6 / ° C to 4 · 5 X 1 0 _6 / ° C), so the temperature rise and fall in polycrystalline silicon chemical vapor deposition (C VD) process In the process, not only the generation of polycrystalline silicon particles can be reduced, but also the number of contention of the furnace tube is less, so it is widely used in the industry to make half The rule of precursor process ends. However, in a high temperature furnace tube devices, limited by the foregoing (back, .., King described) two hard solid can not break through the outer tube can not be directly applied to produce silicon carbide.

Page 10

J 449789 V. Description of the invention (8) However, the design of the double-layer outer tube (and silicon carbide outer tube) in the furnace tube device 40 of the present invention has the following advantages: (1) The thermal expansion coefficient of quartz is about 0.5 5 to 0.7 (X 1 0 _ is far from the thermal expansion coefficient of the polycrystalline silicon to be deposited. It is clear that the silicon carbide material with a coefficient of thermal expansion (CTE) similar to that of polycrystalline silicon has an inner tube and an outer tube. The deposition process flows along the direction 58 in Figure 2. The main contact is less likely to generate micro-stone inner tube 50, and the outer wall of carbonized carbide outer tube 50 has a nitrogen gas to form a buffer layer 62. Therefore, the flow of silicon methane is very low. The outer wall of the quartz outer tube 4 6 should avoid polycrystalline silicon particles generated on the inner wall of the quartz outer tube 4 6 and affect or clean the furnace tube device 40. (2) The outer outer layer 4 6 is still made of quartz as the material. The inside of the valve is completely isolated from the outside, and the siloxane gas of polysilicon precipitation does not leak out. On the other hand, the heat transfer of quartz is low, so when the outer tube 4 6 is sealed with a ring seal 6, the ring is sealed. Completeness of gasket 5 6 and sealing of furnace tube device 40 Compared with the conventionally made furnace tube device 10, the present invention uses a double-layer outer tube design of tube 50 and quartz outer tube 46. The use of carbonization avoids the generation of polycrystalline silicon particles to ensure the wafer surface and the furnace tube. Clarity, thereby reducing the number of times of cleaning and purification of the furnace tube device. In addition, a thermal buffer layer formed by passing nitrogen gas between the outer tubes can not only convert the heat generated by the temperature difference between the silicon outer tube and the quartz outer tube, but also avoid carbonization The process gas of the silicon inner tube is leaked out to the silicon carbide quartz outer tube 6/0 C), so when the present + production dual, the carbonized gas barrier of the gas flow particles contacted the hot wall, and when the furnace surface was assembled on the wafer surface The use of the derivative coefficient can ensure the degree. Silicon carbide outside the silicon tube to clean the device, double-layer to slow down the carbon force, and more between the outer tube and the 449 78 9 5 'Invention Note (9) Quartz outer tube. The above are only the preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the scope of the patent application of the present invention shall fall within the scope of the patent of the present invention.

Page 12 449 789-Simple illustration of the diagram Simple illustration of the diagram Figure 1 is a schematic diagram of a conventional semiconductor furnace tube device. FIG. 2 is a schematic diagram of a semiconductor furnace tube device according to the present invention. Symbols shown in the figure 10, 40 furnace tube device 12, 42 intake air grab 14, 44 flat plate 1 6 '46 quartz outer tube 18' 48 silicon carbide inner tube 22 '52 wafer boat 24 > 54 air outlet 26, 5 6 Annular gasket, v. F ί._) '28' 58 Gas direction 50 Silicon carbide outer tube 1 * 62 Thermal buffer layer

Page 13

Claims (1)

4 4 9 789 VI. Scope of patent application 1. — A furnace tube device with a double-layer outer tube used to pass in a process gas; a body to form a thin film layer on the surface of a wafer, the furnace The tube device includes: a flat plate; a quartz outer tube provided on the flat plate to isolate the furnace tube device from the outside; a silicon carbide (SiC) outer tube 1 is provided on the flat plate and in the quartz outer tube to prevent particles of the process gas from remaining on the inner wall of the quartz outer tube; a carbonized carbide inner tube (i ner tube) is provided on the flat plate And in the silicon carbide outer tube; and a boat disposed on the flat plate and in the silicon carbide inner tube to carry the wafer. 2. For the device according to item 1 of the patent application scope, wherein the furnace tube further includes an air intake, the flat plate is the top surface of the air inlet face, and the flat plate includes an opening tightly connected to the bottom of the silicon carbide inner tube. , Used to make the incoming process gas enter the silicon carbide inner tube. 3. For the device in the scope of patent application, the silicon carbide outer tube and the quartz outer tube further include a thermal buffer layer for slowing down the temperature difference between the silicon carbide outer tube and the quartz outer tube. Impact. 4. For the device in the scope of patent application item 3, wherein the thermal buffer layer is composed of Page 14 449789 VI. Patent application enclosure; a region filled with gas, and the pressure in this region is greater than or equal to the pressure of the gas in the silicon carbide inner tube f to avoid the following in the silicon carbide inner tube: The gas is leaked between the silicon carbide outer tube and the quartz outer tube. 5. The device according to item 4 of the patent application, wherein the furnace tube device is separately packaged. It contains an air extraction device connected to the outlet of the thermal buffer layer for extracting the filling body. 6. The device according to item 4 of the patent application, wherein the filling gas system is; nitrogen. 7. For the device in the scope of patent application, the furnace tube device further comprises a closing device provided between the quartz outer tube and the flat plate for closing the furnace tube device so that the furnace tube device can reach An approximate vacuum state. 1 8. The device according to item 1 of the scope of patent application, wherein the furnace tube device is used to perform a polycrystalline silicon (ρ Ο I y S i 1 i C ο η) deposition process, and the silicon carbide; the outer tube system is used To prevent the polycrystalline silicon particles from remaining on the inner wall surface of the quartz outer tube. 9. A semiconductor furnace tube device comprising: a flat plate; a composite outer tube is disposed on the flat plate, and the composite outer tube consists of The outer part contains a quartz outer tube composed of a quartz layer, a thermal buffer layer, and ^ 4978 9_; __________ VI. Application for a patent liyuan 丨 'and-silicon carbide (S i C) an outer tube, wherein the thermal buffer layer is used to reduce the stress between the quartz outer tube and the silicon carbide outer tube; ~ a carbonized carbide inner tube (i ner tube), disposed on the flat plate and the A composite outer tube; and a wafer boat (b oat), which is disposed on the flat plate and in the silicon carbide inner tube and is used to carry a wafer. I 1 0. The device according to item 9 of the patent application scope, wherein the furnace tube further comprises an air inlet chamber, the flat plate is the top surface of the air inlet chamber, and the flat plate includes an opening and the bottom of the silicon carbide inner tube The tight connection is used to allow the incoming process gas to enter the silicon carbide inner tube. I 1 1. The device according to item 9 of the scope of patent application, wherein the thermal buffer layer is composed of a region filled with i gas, and the pressure in the region is greater than or equal to the pressure of the gas in the inner tube of silicon carbide, To prevent the gas in the silicon carbide inner tube from leaking out between the silicon carbide outer tube and the quartz outer tube. 12. The device according to item 11 of the scope of patent application, wherein the furnace tube device further comprises an air extraction device connected to the outlet of the thermal buffer layer for extracting the filled gas body. I " 1 3. The device according to item 11 of the patent application scope, wherein the filling gas system is nitrogen. Page 16 4 4 9 7as _______; __ VI. Scope of patent application and a silicon carbide (S i C) outer tube composed of a silicon carbide layer, wherein the thermal buffer layer is used to reduce the quartz outer tube and the carbonization Stress between silicon outer tubes; a carbonized petrol inner tube (i η nertube) provided on the plate and in the composite outer tube; and a wafer boat (b 0a ΐ) provided on the plate The upper part and the inner part of the silicon carbide tube are used to carry the wafer. 10. The device according to item 9 of the scope of patent application, wherein the furnace tube further comprises an air inlet chamber, the flat plate is a top surface of the air inlet chamber, and the flat plate includes an opening closely contacting the bottom of the silicon carbide inner tube Connected to allow the incoming process gas to enter the silicon carbide inner tube. 1 1. The device according to item 9 of the scope of patent application, wherein the thermal buffer layer is composed of a region filled with gas, and the pressure in the region is greater than or equal to the pressure of the gas in the inner tube of silicon carbide to avoid the The gas in the silicon carbide inner tube leaks out between the silicon carbide outer tube and the quartz outer tube. 12. The device according to item 11 of the scope of patent application, wherein the furnace tube device additionally includes an air extraction device connected to the outlet of the thermal buffer layer for extracting the filled gas body. 1 3. The device according to item 11 of the scope of patent application, wherein the filling gas system is nitrogen. Page 16 4 4 9 78 9-VI. Application for patent scope 1 4. For the device of scope 9 of the patent application, the furnace tube device further includes a closed device located between the quartz outer tube and the flat plate. The furnace tube device is closed so that the furnace tube device can reach an approximate vacuum state. 15. The device of item 9 in the scope of the patent application, wherein the furnace tube device is used to perform a polycrystalline silicon (ρ ο 1 ysi 1 ic ο η) deposition process, and the silicon carbide outer tube is used to avoid the polycrystalline silicon Particles remain on the inner wall of the outer quartz tube. Page 17