Continuous growth method for silicon carbide epitaxial furnace

Abstract

The invention discloses a continuous growth method for a silicon carbide epitaxial furnace, which is characterized in that manual wafer placement is replaced by the design of a transmission chamber provided with a wafer transfer mechanism, a plurality of wafers can be introduced at one time and continuously grow, so that the production efficiency is improved, and manual interference is reduced due to full mechanization of wafer placement and transfer. The product yield is improved; the production cost is reduced; meanwhile, a substrate slice temporary storage box and an epitaxial wafer temporary storage box which are communicated with the transmission chamber are arranged, the temporary storage boxes can store substrates or epitaxial wafers, gate valves are arranged between the chambers, and when the temporary storage boxes are opened, the gate valves rise to isolate the outside from being in contact with the transmission chamber, so that the cleanliness of the chambers is guaranteed; after the temporary storage box is closed, the gate valve falls down to achieve communication of the cavity.

Description

Technical Field

[0001] The invention belongs to the technical field of silicon carbide epitaxial growth, and in particular, relates to a continuous growth method for a silicon carbide epitaxial furnace. Background Art

[0002] A silicon carbide epitaxial furnace is a device used to produce silicon carbide epitaxial wafers. In the production of silicon carbide epitaxial wafers, the substrate wafer needs to be transferred multiple times. The usual operation method is that the operator uses a vacuum suction pen to transfer a single wafer into the loading chamber. On the one hand, manual wafer placement in this process is inconsistent due to the inconsistent techniques of different operators and even the different operating techniques of the same operator in different states, which easily causes the risk of substrate wafer falling and scratching, resulting in poor epitaxial quality or even scrapping; on the other hand, manual wafer placement increases labor costs, and cannot grow continuously, the efficiency is extremely low, and the accuracy of wafer placement by human eye is poor.

[0003] Therefore, there is an urgent need to provide a method that can achieve continuous growth of epitaxial wafers and improve production efficiency and product yield. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a continuous growth method for a silicon carbide epitaxial furnace, which aims to achieve continuous growth of epitaxial wafers and improve production efficiency and product yield.

[0005] To achieve the above object, the present invention adopts the following technical solution: a continuous growth method for a silicon carbide epitaxial furnace, comprising the following steps: 1) A continuous growth device for a silicon epitaxial furnace is provided, the continuous growth device comprising a transmission chamber, a substrate sheet temporary storage box, a substrate sheet assembly chamber, an epitaxial wafer temporary storage box, an epitaxial wafer cooling chamber and a reaction chamber, the substrate sheet temporary storage box is connected to the transmission chamber via the substrate sheet assembly chamber, the epitaxial wafer temporary storage box is connected to the transmission chamber via the epitaxial wafer cooling chamber, the reaction chamber is connected to the transmission chamber, and a first separation table and a carrying ring are provided in the substrate sheet assembly chamber, a second separation table is provided in the epitaxial wafer cooling chamber, and a wafer transfer mechanism is provided in the transmission chamber; first to fourth gate valves are provided respectively between the substrate sheet temporary storage box and the substrate sheet assembly chamber, between the substrate sheet assembly chamber and the transmission chamber, between the epitaxial wafer temporary storage box and the epitaxial wafer cooling chamber, and between the epitaxial wafer cooling chamber and the transmission chamber; 2) Open the substrate sheet temporary storage box, place the first plug with the substrate sheet placed in the designated position of the substrate sheet temporary storage box, close the substrate sheet temporary storage box, balance the pressure of the substrate sheet temporary storage box, the substrate sheet assembly chamber and the transfer chamber, and then open the first gate valve and the second gate valve; 3) Start the wafer transfer mechanism to take the substrate. When the substrate reaches the substrate assembly chamber, close the second gate valve, and the wafer transfer mechanism lifts the substrate to the specified position of the substrate assembly chamber; 4) The first separation platform rises up until the substrate is lifted, at which time the wafer transfer mechanism retracts, and then the first separation platform descends to complete the splicing of the substrate and the carrier ring; 5) The wafer transfer mechanism moves to lift the substrate and the carrier ring and transfer them to the transfer chamber, and the first gate valve is closed. Then, the wafer transfer mechanism transfers the substrate and the carrier ring to the reaction chamber to start growth; 6) After the growth is completed, the third gate valve is opened, and the wafer transfer mechanism places the epitaxial wafer and the carrier ring on the second separation table, and then the third gate valve is closed to cool the epitaxial wafer and the carrier ring in the epitaxial wafer cooling chamber; 7) At the same time, the wafer transfer mechanism moves again and repeats steps 3)-5). During this period of time, the epitaxial wafer and the carrier ring in the epitaxial wafer cooling chamber are cooled down, the second separation table rises up and holds up the epitaxial wafer, and the epitaxial wafer and the carrier ring are separated. The wafer transfer mechanism holds up the epitaxial wafer again, the second separation table descends, the fourth gate valve is opened, and the wafer transfer mechanism puts the grown epitaxial wafer into the second plug in the epitaxial wafer temporary storage box; 8) The wafer transfer mechanism retracts and steps 3) to 7) are repeated until all substrate sheets in the first plug are grown and the continuous growth process ends.

[0006] Preferably, after the growth is completed, the temperature of the epitaxial wafer is cooled to 900° C. before performing step 5).

[0007] Preferably, the first separation platform and the second separation platform both include a lifting boss and a periphery arranged outside the lifting boss, and the carrying ring is placed on the periphery. The splicing and separation of the substrate sheet and the carrying ring and the separation of the epitaxial wafer and the carrying ring are achieved by rising or falling the lifting boss.

[0008] Preferably, the wafer transfer mechanism adopts a multi-axis robotic arm, and the multi-axis robotic arm is provided with a finger structure suitable for clamping the wafer and the carrier ring to realize the wafer transfer.

[0009] Preferably, the cross section of the transfer chamber is a regular octagon, and the substrate sheet temporary storage box, the epitaxial wafer temporary storage box and the reaction chamber are respectively arranged on three non-adjacent sides of the transfer chamber.

[0010] Preferably, a maintenance window is provided on the top of the transmission chamber, a maintenance end cover is provided on the maintenance window, and a maintenance end cover opening and closing mechanism is provided on the fourth side of the transmission chamber, and the maintenance end cover opening and closing mechanism is connected to the maintenance end cover.

[0011] Preferably, the substrate sheet temporary storage box and the epitaxial wafer temporary storage box are both provided with an upper end cover for opening or closing the substrate sheet temporary storage box and the epitaxial wafer temporary storage box to put in or take out the first plug or the second plug.

[0012] Preferably, the first plug and the second plug can assemble multiple substrate wafers and epitaxial wafers at one time.

[0013] The present invention adopts the above technical solution, which has the following advantages: 1. The present invention replaces manual wafer placement by designing a transfer chamber with a robotic arm, which can import multiple wafers at one time and grow them continuously to improve production efficiency. The full mechanization of wafer placement and transfer reduces manual interference, improves product yield and reduces production costs.

[0014] 2. The present invention is provided with a substrate sheet temporary storage box and an epitaxial wafer temporary storage box connected to the transfer chamber. The temporary storage box can store substrates or epitaxial wafers. At the same time, a gate valve is arranged between each chamber. When the temporary storage box is opened, the gate valve rises to isolate the contact between the outside and the transfer chamber to ensure the cleanliness of the chamber; after the temporary storage box is closed, the gate valve falls to realize the connection between the chambers. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Throughout the accompanying drawings, the same reference numerals are used to represent the same components. In the accompanying drawings: Figure 1 A schematic diagram of the explosion structure of a continuous growth device provided by one embodiment of the present invention; Figure 2 An assembly diagram of the continuous growth device provided for this embodiment of the present invention.

[0016] The reference numerals in the figures are as follows: 1-transfer chamber; 2-substrate assembly chamber; 3-first gate valve; 4-substrate temporary storage box; 5-first plug; 6-substrate; 7-second gate valve; 8-carrying ring; 9-first separation table; 10-mechanical arm; 11-epitaxial wafer cooling chamber; 12-second separation table; 13-epitaxial wafer; 14-second plug; 15-epitaxial wafer temporary storage box; 16-third gate valve; 17-fourth gate valve; 18-maintenance end cover; 19-maintenance end cover opening and closing mechanism; 20-upper end cover. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present invention clearer, the specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0018] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0019] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0020] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0022] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0023] The present invention provides a continuous growth method for a silicon carbide epitaxial furnace. The method replaces manual wafer placement by designing a transmission chamber with a wafer transfer mechanism, and can introduce multiple wafers at one time and grow them continuously, thereby improving production efficiency. The full mechanization of wafer placement and transfer reduces manual interference, improves product yield and reduces production costs. At the same time, the present invention is provided with a substrate wafer temporary storage box and an epitaxial wafer temporary storage box connected to the transmission chamber. The temporary storage box can store substrates or epitaxial wafers, and gate valves are arranged between the chambers. When the temporary storage box is opened, the gate valve rises to isolate the outside from contact with the transmission chamber, thereby ensuring the cleanliness of the chamber. After the temporary storage box is closed, the gate valve falls to achieve communication between the chambers.

[0024] The continuous growth method for a silicon carbide epitaxial furnace provided by an embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0025] The continuous growth method for a silicon carbide epitaxial furnace provided in this embodiment is based on the following Figure 1 , Figure 2The continuous growth device for a silicon carbide epitaxial furnace is shown, and the continuous growth device includes: a transfer chamber 1 for providing an environment for transferring wafers; a substrate sheet temporary storage box 4, which is arranged on the first side of the transfer chamber 1, and the substrate sheet temporary storage box 4 is used to accommodate a first plug 5, in which a plurality of substrate sheets 6 are placed; a substrate sheet assembly chamber 2, which is arranged between the substrate sheet temporary storage box 4 and the transfer chamber 1, one end of the substrate sheet assembly chamber 2 is connected to the transfer chamber 1, and a first gate valve 3 is arranged at the connection point between the two, and the other end of the substrate sheet assembly chamber 2 is connected to the substrate sheet temporary storage box 4, and a second gate valve 7 is arranged at the connection point between the two; a first separation table 9, which is arranged in the substrate sheet assembly chamber 2, and the first separation table 9 has a lifting action end; a carrying ring 8, which is suitable for carrying the substrate sheet 6 and is arranged on the first separation table 9, and the first separation table 9 is lifted and lowered to realize the splicing and separation of the substrate sheet 6 and the carrying ring 8; an epitaxial wafer temporary storage box 15, The epitaxial wafer temporary storage box 15 is arranged at the second side of the transmission chamber 1, and is used to accommodate the second plug 14, and the second plug 14 is used to place the epitaxial wafer 13 that has been grown; the epitaxial wafer cooling chamber 11 is arranged between the epitaxial wafer temporary storage box 15 and the transmission chamber 1, one end of the epitaxial wafer cooling chamber 11 is connected to the transmission chamber 1, and a third gate valve 16 is arranged at the connection point between the two, and the other end of the epitaxial wafer cooling chamber 11 is connected to the epitaxial wafer temporary storage box 15, and a fourth gate valve 17 is arranged at the connection point between the two; the second separation platform 12 is arranged in the epitaxial wafer cooling chamber 11, and the second separation platform 12 also has a lifting and lowering action end, and the epitaxial wafer 13 and the carrying ring 8 are separated by lifting and lowering the second separation platform 12; the robot arm 10 is arranged in the transmission chamber 1, and is used to realize the transfer of the substrate 6 and the epitaxial wafer 13; the reaction chamber (not shown in the figure) is arranged on the third side of the transmission chamber 1, and is used to provide an environment for the growth of the substrate 6.

[0026] Specifically, the continuous growth method for a silicon carbide epitaxial furnace provided in this embodiment includes the following steps: 1) Open the substrate sheet temporary storage box 4, place the first plug 5 with the substrate sheet 6 placed in the specified position of the substrate sheet temporary storage box 4, close the substrate sheet temporary storage box 4, balance the pressure of the substrate sheet temporary storage box 4, the substrate sheet assembly chamber 2 and the transfer chamber 1, and then open the first gate valve 3 and the second gate valve 7; 2) Start the robot arm 10 to take the substrate sheet 6. When the substrate sheet 6 reaches the substrate sheet assembly chamber 2, close the first gate valve 3 (to reduce the impact on the ungrown substrate sheet 6 in the first plug 5), and the robot arm 10 lifts the substrate sheet 6 to the specified position of the substrate sheet assembly chamber 2; 3) The first separation table 9 rises up until it lifts the substrate sheet 6 to a certain height, at which time the robot arm 10 retracts a short distance (without affecting the cooperation between the substrate sheet 6 and the carrier ring 8 when they descend), and then the first separation table 9 descends to complete the splicing of the substrate sheet 6 and the carrier ring 8; 4) The robot arm 10 moves to lift the substrate sheet 6 and the carrier ring 8 and transfers them to the transfer chamber 1, and closes the second gate valve 7. Then, the robot arm 10 transfers the substrate sheet 6 and the carrier ring 8 to the reaction chamber to start growth; 5) After the growth is completed and the temperature of the epitaxial wafer 13 is lowered to 900° C., the robot arm 10 places the epitaxial wafer 13 and the carrier ring 8 on the second separation table 11. At this time, the third gate valve 16 is closed to cool the epitaxial wafer 13 and the carrier ring 8 in the epitaxial wafer cooling chamber 2; 6) At the same time, the robot arm 10 moves again and repeats steps 2)-4). During this period, the epitaxial wafer 13 and the carrier ring 8 in the epitaxial wafer cooling chamber are cooled, the second separation table 11 rises upward and holds up the epitaxial wafer 13, and the epitaxial wafer 13 and the carrier ring 8 are separated. The robot arm 10 holds up the epitaxial wafer 13 again, the second separation table 11 descends, and the robot arm 10 puts the grown epitaxial wafer 13 into the second plug 14 in the epitaxial wafer temporary storage box 15; 7) The robot arm 10 retracts and steps 2) to 6) are repeated until all substrate sheets 6 in the first plug 5 are grown, and the continuous growth process ends.

[0027] In the above embodiment, preferably, the first separation table 9 and the second separation table 12 both include a lifting boss and a periphery arranged outside the lifting boss, and the carrying ring 8 is placed on the periphery. The splicing and separation of the substrate sheet 6 and the carrying ring 8 and the separation of the epitaxial wafer 13 and the carrying ring 8 are achieved by rising or falling the lifting boss.

[0028] In the above embodiment, preferably, the robot 10 is a multi-axis robot, and the multi-axis robot is provided with a finger structure suitable for clamping the wafer (ie, the substrate wafer 6 or the epitaxial wafer 13) and the carrying ring 8 to realize the transfer of the wafer.

[0029] In the above embodiment, preferably, the cross section of the transfer chamber 1 is a regular octagon, and the substrate temporary storage box 4 , the epitaxial wafer temporary storage box 15 and the reaction chamber are respectively arranged on three non-adjacent sides of the transfer chamber 1 .

[0030] In the above embodiment, preferably, a maintenance window is provided on the top of the transmission chamber 1, a maintenance end cover 18 is provided on the maintenance window, and a maintenance end cover opening and closing mechanism 19 is provided on the fourth side of the transmission chamber 1, and the maintenance end cover opening and closing mechanism 19 is connected to the maintenance end cover 18, so that the maintenance end cover 18 can be opened to maintain or clean the transmission chamber 1 and the robot arm 10.

[0031] In the above embodiment, preferably, both the substrate temporary storage box 4 and the epitaxial wafer temporary storage box 15 are provided with an upper end cover 20 for opening or closing the substrate temporary storage box 4 and the epitaxial wafer temporary storage box 15 to put in or take out the first plug 5 or the second plug 14 .

[0032] In the above embodiment, preferably, the first plug 5 and the second plug 14 can assemble multiple substrate wafers 6 and epitaxial wafers 13 at one time.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A continuous growth method for a silicon carbide epitaxial furnace, characterized in that: The following steps are involved: 1) A continuous growth device for a silicon epitaxial furnace is provided, the continuous growth device comprising a transmission chamber, a substrate sheet temporary storage box, a substrate sheet assembly chamber, an epitaxial wafer temporary storage box, an epitaxial wafer cooling chamber and a reaction chamber, the substrate sheet temporary storage box is connected to the transmission chamber via the substrate sheet assembly chamber, the epitaxial wafer temporary storage box is connected to the transmission chamber via the epitaxial wafer cooling chamber, the reaction chamber is connected to the transmission chamber, and a first separation table and a carrying ring are provided in the substrate sheet assembly chamber, a second separation table is provided in the epitaxial wafer cooling chamber, and a wafer transfer mechanism is provided in the transmission chamber; first to fourth gate valves are provided respectively between the substrate sheet temporary storage box and the substrate sheet assembly chamber, between the substrate sheet assembly chamber and the transmission chamber, between the epitaxial wafer temporary storage box and the epitaxial wafer cooling chamber, and between the epitaxial wafer cooling chamber and the transmission chamber; 2) Opening the substrate sheet temporary storage box, placing the first plug with the substrate sheet placed in the designated position of the substrate sheet temporary storage box, closing the substrate sheet temporary storage box, balancing the pressure of the substrate sheet temporary storage box, the substrate sheet assembly chamber and the transfer chamber, and then opening the first gate valve and the second gate valve; 3) Start the wafer transfer mechanism to take the substrate. When the substrate reaches the substrate assembly chamber, close the second gate valve, and the wafer transfer mechanism lifts the substrate to the specified position of the substrate assembly chamber; 4) The first separation platform rises up until the substrate is lifted, at which time the wafer transfer mechanism retracts, and then the first separation platform descends to complete the splicing of the substrate and the carrier ring; 5) The wafer transfer mechanism moves to lift the substrate and the carrier ring and transfer them to the transfer chamber, and the first gate valve is closed. Then, the wafer transfer mechanism transfers the substrate and the carrier ring to the reaction chamber to start growth; 6) After the growth is completed, the third gate valve is opened, and the wafer transfer mechanism places the epitaxial wafer and the carrier ring on the second separation table, and then the third gate valve is closed to cool the epitaxial wafer and the carrier ring in the epitaxial wafer cooling chamber; 7) At the same time, the wafer transfer mechanism moves again and repeats steps 3)-5). During this period of time, the epitaxial wafer and the carrier ring in the epitaxial wafer cooling chamber are cooled down, the second separation table rises up and holds up the epitaxial wafer, and the epitaxial wafer and the carrier ring are separated. The wafer transfer mechanism holds up the epitaxial wafer again, the second separation table descends, the fourth gate valve is opened, and the wafer transfer mechanism puts the grown epitaxial wafer into the second plug in the epitaxial wafer temporary storage box; 8) The wafer transfer mechanism retracts and steps 3) to 7) are repeated until all substrate sheets in the first plug are grown and the continuous growth process ends.

2. The continuous growth method according to claim 1, characterized in that: After the growth is completed, the epitaxial wafer is cooled to 900°C and then step 5 is performed).

3. The continuous growth method according to claim 1, characterized in that: The first separation platform and the second separation platform both include a lifting boss and a periphery arranged outside the lifting boss, and the carrying ring is placed on the periphery. The lifting boss is raised or lowered to achieve the splicing and separation of the substrate sheet and the carrying ring, and the separation of the epitaxial wafer and the carrying ring.

4. The continuous growth method according to claim 1, characterized in that: The wafer transfer mechanism adopts a multi-axis mechanical arm, and the multi-axis mechanical arm is provided with a finger structure suitable for clamping the wafer and the carrying ring to realize the wafer transfer.

5. The continuous growth method according to any one of claims 1 to 4, characterized in that: The cross section of the transmission chamber is a regular octagon, and the substrate sheet temporary storage box, the epitaxial wafer temporary storage box and the reaction chamber are respectively arranged on three non-adjacent sides of the transmission chamber.

6. The continuous growth method according to claim 5, characterized in that: A maintenance window is arranged on the top of the transmission chamber, a maintenance end cover is arranged on the maintenance window, and a maintenance end cover opening and closing mechanism is arranged on the fourth side of the transmission chamber, and the maintenance end cover opening and closing mechanism is connected to the maintenance end cover.

7. The continuous growth method according to any one of claims 1 to 4, characterized in that: The substrate temporary storage box and the epitaxial wafer temporary storage box are both provided with an upper end cover for opening or closing the substrate temporary storage box and the epitaxial wafer temporary storage box to put in or take out the first plug or the second plug.

8. The continuous growth method according to any one of claims 1 to 4, characterized in that: The first plug and the second plug can assemble multiple substrate wafers and epitaxial wafers at one time.

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