A boat slot spacing adjustment device for an LPCVD apparatus

Abstract

The application discloses a wafer boat slot interval adjusting device for an LPCVD device, belongs to the technical field of semiconductor manufacturing equipment, and is applied to wafer bearing interval adjustment in a vertical LPCVD device. In view of the problem that in the existing LPCVD device, a fixed slot interval structure is usually adopted for the wafer boat, the relative positions between wafers cannot be adjusted in the deposition process, and the film deposition uniformity in different areas is difficult to improve, the application adopts an in-furnace bearing module, a cross-vacuum boundary transmission module and an out-of-furnace driving module, supports a wafer bearing structure through a quartz push rod, realizes in-furnace and out-of-furnace isolation by using a bellows sealing structure, and independently adjusts the wafer boat slot interval. The application improves the stability of the wafer bearing system and realizes high-precision adjustment of the wafer boat slot interval.

Description

Technical Field

[0001] This invention relates to the field of semiconductor integrated circuit manufacturing equipment technology, and more specifically to a crystal boat slot spacing adjustment device for LPCVD equipment. Background Technology

[0002] Low-pressure chemical vapor deposition (LPCVD) equipment is an important process equipment used for thin film deposition in semiconductor manufacturing, and is widely used in the preparation of thin films such as silicon nitride, polycrystalline silicon, and oxides. In the LPCVD process, multiple wafers are typically loaded into a wafer boat at a certain spacing and then fed as a whole into a high-temperature reaction chamber to complete the thin film deposition.

[0003] Because the reactive gas is gradually consumed as it flows along the axial direction of the wafer boat, the reactant concentration varies at different locations on the wafer surface. This can easily lead to inconsistent thin film deposition rates and decreased film thickness uniformity between wafers. Therefore, adjusting the slot spacing between wafers in different areas of the wafer boat to make the reactive gas distribution more uniform is an effective technical solution to improve the consistency of mass wafer deposition.

[0004] However, existing LPCVD equipment typically employs a fixed boat structure, meaning the wafer carrier trench spacing cannot be adjusted during deposition based on reactant gas distribution and process requirements. Because reactant gases are consumed as they flow along the boat, reactant concentrations vary across different wafer locations, and a fixed trench spacing cannot compensate for this variation. This leads to inconsistent film deposition rates between wafers, affecting film thickness uniformity. Furthermore, existing fixed boat structures lack high-precision, low-contamination spacing adjustment mechanisms, failing to meet the requirements of deposition uniformity and process adaptability in advanced semiconductor manufacturing. Therefore, a boat trench spacing adjustment device for LPCVD equipment is needed to adjust the wafer spacing and improve film deposition uniformity. Summary of the Invention

[0005] The purpose of this invention is to provide a wafer boat spacing adjustment device for LPCVD equipment, so as to solve the problem that the wafer boat in the existing LPCVD equipment usually adopts a fixed spacing structure, which cannot adjust the wafer spacing according to the changes in the distribution of reactive gas during the deposition process, resulting in insufficient deposition uniformity in different areas of the wafer.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A wafer boat spacing adjustment device for LPCVD equipment includes an in-furnace support module, a cross-vacuum boundary transmission module, and an out-of-furnace drive module. The in-furnace support module includes a quartz top plate (1), a quartz guide rod (2), a wafer support structure (3), a quartz pusher (4), and an in-furnace bottom plate (5). The quartz top plate (1) and the in-furnace bottom plate (5) are connected by the quartz guide rod (2) to form a support frame. The wafer support structure (3) is slidably arranged along the axial direction of the quartz guide rod (2) to support the wafer and realize wafer spacing adjustment. There are multiple sets of wafer support structures (3), and each set of wafer support structures (3) is independently supported and driven by the quartz pusher (4). The quartz pusher (4) adopts a multi-point concentric arrangement, and each set of quartz pushers (4) is evenly distributed along the circumference, so that the wafer support structure (3) is subjected to uniform support force, improving the stability during the movement. The cross-vacuum boundary transmission module includes an adapter sleeve (6), a vacuum flange (7), a bellows (8), and a metal drive shaft (9). Furthermore, to ensure the reliability of the device under high-temperature conditions, the upper end of the adapter sleeve (6) is provided with a socket, and the lower end of the quartz push rod (4) is inserted into the socket with a clearance fit. A high-temperature buffer pad is placed at the bottom of the socket. The adapter sleeve (6) and the quartz push rod (4) are connected by a transversely inserted high-temperature resistant pin. The hole on the quartz push rod (4) for the high-temperature resistant pin to pass through is a long, narrow hole or an enlarged hole with a pre-reserved thermal expansion gap, thereby absorbing the thermal expansion difference under high-temperature conditions and preventing damage to the quartz push rod due to thermal stress. The upper end of the metal drive shaft (9) is connected to the lower end of the adapter sleeve (6) by a threaded connection, and a locking pin is provided laterally at the threaded connection to prevent the metal drive shaft (9) and the adapter sleeve (6) from rotating and loosening relative to each other under thermal cycling conditions, thereby achieving stable and reliable transmission of external driving force to the quartz actuator inside the furnace. The bellows (8) is sleeved on the outside of the metal drive shaft (9), and the upper end of the bellows (8) is sealed to the adapter sleeve (6), and the lower end is sealed to the vacuum flange (7), so that the adapter sleeve (6), the bellows (8) and the vacuum flange (7) together form a sealed isolation structure to isolate the process atmosphere inside the reaction chamber from the external ambient air and maintain the vacuum state of the reaction chamber. The external drive module includes a shaped synchronous support plate (10), a linear guide rail (11), a lead screw (12) and a motor (13). The lower end of the metal drive shaft (9) is connected to the irregular synchronous support plate (10). The motor (13) drives the lead screw (12) to rotate, so that the irregular synchronous support plate (10) moves along the direction of the linear guide rail (11). Through the metal drive shaft (9), the adapter sleeve (6) and the quartz push rod (4), the wafer support structure (3) is lifted and lowered to realize the adjustment of the gap between the crystal boat slots.

[0008] Furthermore, the irregularly shaped synchronous tray (10) adopts a stepped arrangement structure, with the transmission mechanisms at different heights staggered to avoid spatial interference between multiple sets of drive mechanisms.

[0009] Compared with the prior art, the present invention has the following beneficial effects:

[0010] (1) By setting up an isolated power transmission structure between the quartz push rod inside the furnace and the metal transmission shaft outside the furnace, the present invention enables the high-temperature reaction zone to mainly use quartz material for motion transmission, thereby reducing the impact of metal parts on the process environment.

[0011] (2) The present invention forms a sealed structure by means of a bellows, a transition sleeve and a vacuum flange, so as to maintain the stability of the vacuum environment of the reaction chamber while realizing motion transmission.

[0012] (3) The present invention uses a multi-point concentric support structure to make the wafer support structure more uniformly stressed, avoiding the tilting and deformation caused by traditional single-point support.

[0013] (4) The present invention uses multiple independent driving structures to adjust the wafer trench spacing in different regions, thereby improving the uniformity of LPCVD thin film deposition. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall three-dimensional isometric structure of a crystal boat tank spacing adjustment device for LPCVD equipment provided in an embodiment of the present invention.

[0015] Figure 2 This is a wafer support structure diagram of a wafer boat spacing adjustment device for LPCVD equipment provided in an embodiment of the present invention.

[0016] Figure label:

[0017] 1. Quartz top plate; 2. Quartz guide rod; 3. Wafer support structure; 4. Quartz push rod; 5. Furnace bottom plate; 6. Adapter sleeve; 7. Vacuum flange; 8. Bellows; 9. Metal drive shaft; 10. Irregular synchronous support plate; 11. Linear guide rail; 12. Lead screw; 13. Motor.

[0018] 31. Wafer support teeth; 32. Arc-shaped connecting rod; 33. Vertical column; 34. Bottom connecting column. Detailed Implementation

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings. Figure 1As shown, this embodiment provides a wafer carrier spacing adjustment device for LPCVD equipment. This device is applied in a vertical low-pressure chemical vapor deposition (LPCVD) equipment to adjust the wafer carrier spacing during the deposition process. The device includes an in-furnace carrier module, a cross-vacuum boundary transmission module, and an external drive module. The in-furnace carrier module is located inside the LPCVD reaction chamber and includes a quartz top plate (1), quartz guide rods (2), a wafer carrier structure (3), a quartz push rod (4), and an in-furnace bottom plate (5). The quartz top plate (1) and the in-furnace bottom plate (5) are fixedly connected by three quartz guide rods (2) evenly distributed circumferentially to form a stable carrier frame. The wafer carrier structure (3) is sleeved on the outside of the quartz guide rods (2) and can slide up and down along the axial direction of the quartz guide rods (2). The wafer support structure (3) includes an upper wafer support structure, a middle wafer support structure and a lower wafer support structure arranged in the vertical direction. Each wafer support structure is used to support the wafer at the corresponding position and is supported and driven by an independently set quartz push rod (4), thereby realizing independent adjustment of the wafer support height in different areas. To improve the stability of the wafer support structure (3) during movement, the quartz pushers (4) in this embodiment adopt a multi-point concentric support structure, with a total of nine quartz pushers (4). The nine quartz pushers (4) are arranged in three concentric circles along the radial direction. The three quartz pushers in the inner circle are distributed at 90° intervals along the circumference to support the lower wafer support structure; the three quartz pushers in the middle circle are distributed at 90° intervals along the circumference to support the middle wafer support structure; and the three quartz pushers in the outer circle are distributed at 90° intervals along the circumference to support the upper wafer support structure. Through the above-mentioned multi-point concentric support structure, the wafer support structure (3) receives a uniformly distributed support force during the lifting and adjusting process, avoiding the tilting, jamming, and wafer position displacement problems caused by the traditional single-point support method. Figure 2 As shown, the wafer support structure (3) is preferably an integrally formed quartz structure, which specifically includes wafer support teeth (31), arc-shaped connecting rods (32), vertical columns (33), and bottom connecting columns (34). Among them, there are three vertical columns (33), which are distributed at intervals along the circumference; adjacent vertical columns (33) are connected by two arc-shaped connecting rods (32) that are arranged vertically and vertically to form an overall support frame; multiple wafer support teeth (31) extend from the inner side of each vertical column (33) at equal intervals along the vertical direction, and the three wafer support teeth (31) at the same horizontal height cooperate to form a support groove for stably supporting a single wafer; the bottom connecting column (34) extends downward to the bottom end of the vertical column (33) and is used to concentrically insert with the corresponding quartz push rod (4) below, thereby stably receiving the lifting driving force from the quartz push rod (4) and improving the adjustment accuracy of the wafer boat groove spacing.

[0020] The cross-vacuum boundary transmission module is located between the in-furnace support module and the external drive module, and includes a transition sleeve (6), a vacuum flange (7), a bellows (8), and a metal drive shaft (9). The vacuum flange (7) is installed below the in-furnace bottom plate (5) and is sealed to the bottom of the reaction chamber to maintain the vacuum environment inside the LPCVD reaction chamber. The metal drive shaft (9) passes vertically through the vacuum flange (7), with its upper end connected to the transition sleeve (6) and its lower end connected to the external drive module. The transition sleeve (6) serves as a connection and conversion component between the external metal transmission structure and the in-furnace quartz actuator. Its upper end is connected to the quartz push rod (4), and its lower end is connected to the metal drive shaft (9), enabling the transmission of external driving force to the in-furnace quartz actuator. Furthermore, to adapt to the high-temperature working conditions inside the LPCVD equipment, the upper end of the adapter sleeve (6) is provided with a socket, the lower end of the quartz push rod (4) is inserted into the socket, and a high-temperature resistant buffer pad is provided at the bottom of the socket to reduce the impact stress generated during the thermal cycle. At the same time, the quartz push rod (4) and the adapter sleeve (6) are connected by a high-temperature resistant pin, and the pin hole on the quartz push rod (4) is set as a long hole structure or a reserved thermal expansion compensation gap, so that the quartz push rod (4) can release thermal stress when it generates thermal expansion in a high-temperature environment, and avoid structural damage. The bellows (8) is sleeved on the outside of the metal drive shaft (9). Its upper end is sealed to the adapter sleeve (6) and its lower end is sealed to the vacuum flange (7). The adapter sleeve (6), the bellows (8) and the vacuum flange (7) together form an axially expandable and scalable sealed isolation structure. During the movement of the metal drive shaft (9), the vacuum environment inside the reaction chamber is kept stable. At the same time, the metal transmission mechanism outside the furnace is isolated from the high-temperature deposition area, reducing the risk of metal contamination.

[0021] The external drive module is located outside the reaction chamber and includes a shaped synchronous support plate (10), a linear guide rail (11), a lead screw (12), and a motor (13). The lower end of a metal drive shaft (9) is connected to the shaped synchronous support plate (10), which is mounted on the linear guide rail (11) and can move up and down along the guide direction of the linear guide rail (11). The motor (13) is connected to the lead screw (12), and the shaped synchronous support plate (10) has an internal threaded hole, which is threadedly engaged with the lead screw (12). By controlling the rotation of the motor (13) to drive the lead screw (12) to rotate, the shaped synchronous support plate (10) moves along the direction of the linear guide rail (11) using the threaded transmission principle. The metal drive shaft (9), the adapter sleeve (6), and the quartz push rod (4) drive the corresponding wafer support structure (3) to rise and fall, thereby adjusting the spacing between the wafer trays. The irregularly shaped synchronous tray (10) adopts a stepped arrangement structure, so that multiple sets of transmission mechanisms are staggered in the spatial direction to avoid mechanical interference between different drive mechanisms.

[0022] In actual operation, based on the concentration changes caused by the reaction gas flowing along the axial direction of the crystal boat during LPCVD deposition, the control system sends adjustment commands to the motors (13) in the corresponding areas. The motors (13) drive the lead screws (12) to rotate, causing the irregularly shaped synchronous support plate (10) to generate axial displacement. This displacement is then carried by the metal drive shaft (9), the adapter sleeve (6), and the quartz push rod (4) to move the wafer support structures (3) in different areas, thereby changing the spacing between wafers at different positions. By adjusting the distance between the upper, middle, and lower wafer support structures respectively, the concentration gradient changes caused by the consumption of reaction gas can be compensated, making the supply of reactants on the wafer surface at different positions more uniform, improving the consistency of thin film deposition rate and the uniformity of film thickness. This invention, through the combined design of the in-furnace quartz actuator, the cross-vacuum boundary isolation transmission mechanism, and the external precision drive mechanism, achieves high precision and adjustment of the crystal boat spacing while ensuring the stability of the vacuum environment in the reaction chamber, thus improving the uniformity of thin film deposition and the process adaptability of the LPCVD equipment.

[0023] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A crystal boat spacing adjustment device for LPCVD equipment, the device comprising an in-furnace support module, a cross-vacuum boundary transmission module, and an external drive module; characterized in that, The furnace support module includes a quartz top plate (1), quartz guide rods (2), multiple sets of wafer support structures (3), multiple sets of quartz push rods (4), and a furnace bottom plate (5). The quartz top plate (1) and the furnace bottom plate (5) are connected by multiple quartz guide rods (2). The wafer support structure (3) can slide along the axial direction of the quartz guide rods (2). The multiple sets of wafer support structures (3) are divided into upper, middle and lower wafer support structures arranged in the vertical direction, and are independently supported by quartz push rods (4) at corresponding positions. The multiple sets of quartz push rods (4) are concentrically distributed in the radial direction. The quartz push rods (4) distributed in the outer ring support the upper wafer support structure, the quartz push rods (4) distributed in the middle ring support the middle wafer support structure, and the quartz push rods (4) distributed in the inner ring support the lower wafer support structure. The cross-vacuum boundary transmission module includes an adapter sleeve (6), a vacuum flange (7), a bellows (8), and a metal drive shaft (9); the vacuum flange (7) is located below the furnace bottom plate (5) to seal the bottom of the reaction chamber; the metal drive shaft (9) passes through the vacuum flange (7), the upper end of the metal drive shaft (9) is connected to the lower end of the adapter sleeve (6), and the upper end of the adapter sleeve (6) is connected to the lower end of the quartz push rod (4); the bellows (8) is sleeved on the outside of the metal drive shaft (9), the upper end of the bellows (8) is sealed to the adapter sleeve (6), and the lower end is sealed to the vacuum flange (7) to maintain the vacuum environment inside the reaction chamber during the axial movement of the metal drive shaft (9); The external drive module includes a shaped synchronous support plate (10), a linear guide rail (11), a lead screw (12), and a motor (13). The lower end of the metal drive shaft (9) is connected to the shaped synchronous support plate (10). The shaped synchronous support plate (10) is provided with a threaded hole that matches the lead screw (12). The lead screw (12) passes through the threaded hole and is threadedly engaged with it. The motor (13) drives the lead screw (12) to rotate, so that the shaped synchronous support plate (10) moves along the direction of the linear guide rail (11). The corresponding wafer support structure (3) is lifted and lowered through the metal drive shaft (9), the adapter sleeve (6), and the quartz push rod (4), so as to realize independent adjustment of the wafer boat slot spacing.

2. The crystal boat spacing adjustment device for LPCVD equipment according to claim 1, characterized in that: The wafer support structure (3) includes a vertical column (33), an arc-shaped connecting rod (32) connecting adjacent vertical columns (33), and 10 wafer support teeth (31) disposed on the inner side of the vertical column (33); multiple wafer support teeth (31) at the same horizontal height cooperate to form a wafer support groove; the bottom of the vertical column (33) is provided with a bottom connecting column (34), and the bottom connecting column (34) is concentrically inserted and connected to the upper end of the quartz push rod (4).

3. The crystal boat spacing adjustment device for LPCVD equipment according to claim 1, characterized in that: The upper end of the adapter sleeve (6) is provided with a socket, and the lower end of the quartz push rod (4) is inserted into the socket with clearance fit, and the bottom of the socket is provided with a high temperature resistant graphite buffer pad; the adapter sleeve (6) and the quartz push rod (4) are connected by a horizontally inserted high temperature resistant pin, and the pin hole on the quartz push rod (4) for passing through the high temperature resistant pin is a long strip hole or an enlarged hole with a reserved thermal expansion compensation gap.

4. The crystal boat spacing adjustment device for LPCVD equipment according to claim 1, characterized in that: The upper end of the metal drive shaft (9) is connected to the lower end of the adapter sleeve (6) by a threaded connection, and a locking pin is provided laterally at the threaded connection.

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