Method and device for reducing fragment rate of IGBT epitaxial wafer

Abstract

The invention belongs to the technical field of semiconductor manufacturing, and particularly relates to a method and device for reducing the fragment rate of an IGBT epitaxial wafer, and the method comprises the following steps: S1, loading and positioning: placing a wafer in a supporting disc at the top of a base main body in an epitaxial machine, and positioning the wafer through a stop block on the supporting disc; s2, process execution: starting and implementing an epitaxial growth process; and S3, active separation: after the epitaxial growth is completed, starting a separation assembly arranged on the supporting disc to enable the separation assembly to generate vibration acting on the wafer so as to enable the wafer to be separated from the adhesion part of the supporting disc. According to the invention, the stop blocks are arranged to position the wafer, so that the wafer is prevented from being adhered to the inner wall of the side step due to volume increase in the epitaxial growth process, and the risk of fragmentation caused by small gaps at the adhesion part during wafer taking is reduced.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing technology, specifically a method and apparatus for reducing the breakage rate of IGBT epitaxial wafers. Background Technology

[0002] IGBTs (Insulated Gate Bipolar Transistors), as core power semiconductor devices, are widely used in key fields such as new energy vehicles, rail transportation, smart grids, and power electronic converters due to their excellent performance, including high voltage withstand capability, low conduction loss, and fast switching. The quality and manufacturing stability of IGBTs directly determine the operational reliability of downstream equipment. Epitaxial wafers, as the core basic structure of IGBT devices, have a crucial manufacturing process, and thick epitaxial substrates have become the mainstream choice because they can meet the performance requirements of IGBT devices under high voltage and high current conditions.

[0003] However, in the existing IGBT thick epitaxial wafer fabrication process, wafer breakage has long constrained the improvement of production efficiency and product yield, becoming a technical bottleneck that urgently needs to be solved in the industry. Industry practice and research have found that wafer breakage mainly occurs during the epitaxial growth stage and subsequent clamping processes, and its core causes include the following two aspects: On the one hand, during epitaxial growth, the stepped structure between the wafer end face and the crystal growth substrate is prone to atomic-level adhesion. Since IGBT epitaxial wafers commonly use crystal orientations... <111> The atomic density between crystal planes is significantly lower than that of other crystal orientations. The number of atomic bonds is small and the bonding force is weak, making this crystal orientation region a mechanical weak point of the wafer. Especially for wafers with the

[100] crystal orientation and the notch located on the {100} crystal plane, the cracks are concentrated in the X direction in actual production. The probability of the base step in this direction sticking to the wafer end face is extremely high. When taking off the wafer, the sticking point is prone to generate a small notch. The notch expands rapidly under stress, eventually leading to wafer breakage.

[0004] On the other hand, the thick epitaxial growth process itself will cause the wafer diameter to be larger than that of the initial substrate. In subsequent sorting, transfer and other processes, the chuck needs to clamp the wafer, which can easily lead to uneven mechanical stress during clamping, and thus crush the wafer.

[0005] Therefore, the present invention provides a method and apparatus for reducing the breakage rate of IGBT epitaxial wafers. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by this invention to solve its technical problem is: a method for reducing the breakage rate of IGBT epitaxial wafers, comprising the following steps: S1. Wafer mounting and positioning: The wafer is placed in the support plate on the top of the base body inside the epitaxial machine, and the wafer is positioned by the blocks on the support plate; S2. Process Execution: Start and implement the epitaxial growth process; S3. Active separation: After epitaxial growth is completed, the separation component set on the support disk is activated, so that the separation component generates vibrations acting on the wafer, thereby separating the wafer from the adhesive part of the support disk.

[0008] An apparatus for reducing the breakage rate of IGBT epitaxial wafers, the apparatus being applicable to the aforementioned method for reducing the breakage rate of IGBT epitaxial wafers, wherein the separation component in step S3 includes a piezoelectric ceramic block, the piezoelectric ceramic block being embedded in a mounting groove opened on the surface of the support disk.

[0009] Preferably, multiple stops are provided and are evenly distributed on the inner wall of the support plate.

[0010] Preferably, the piezoelectric ceramic block is configured as an annular shape, and an air blowing component is connected to its central hole for introducing gas into the contact area between the wafer and the support disk.

[0011] Preferably, the air blowing assembly includes a cavity disposed inside the support plate, the bottom of the cavity is connected to an air inlet pipe, and its side is connected to the central hole of the piezoelectric ceramic block through a connecting channel.

[0012] Preferably, a movable block is movably disposed in the central hole of the piezoelectric ceramic block, and the upper end surface of the movable block is flush with the upper end surface of the piezoelectric ceramic block to block the central hole; a driving component is provided in the cavity to drive the movable block to move to open or close the central hole.

[0013] Preferably, the drive assembly includes a movable plate, the bottom of which is fixedly and slidably inserted into the air intake pipe; a pull rope is connected to the side of the movable plate, the other end of which passes through the connecting channel and is connected to the bottom of the movable block.

[0014] Preferably, the inner wall of the central hole of the piezoelectric ceramic block is provided with a movable cavity, and the side wall of the movable block is provided with a limiting block, which limits the sliding within the movable cavity; a spring is provided in the movable cavity below the limiting block.

[0015] Preferably, the movable plate and the connecting block have a through hole at their center, a vertical rod is slidably inserted through the through hole, and its top end is fixed to the top of the cavity. A spring is sleeved on the vertical rod.

[0016] Preferably, multiple support plates are provided, and each is embedded in the surface of the base body; a main pipe is provided at the center of the base body, and the main pipe is connected to the bottom of each support plate through multiple branch pipes, and the air inlet pipe at the bottom of each support plate is correspondingly inserted into the branch pipe.

[0017] The beneficial effects of this invention are as follows: 1. The method and apparatus for reducing the breakage rate of IGBT epitaxial wafers according to the present invention uses baffles to position the wafer. During the wafer placement process, the crystal orientation parts that are prone to breakage during the epitaxial growth process are oriented towards the gap between adjacent baffles, which avoids the wafer from sticking to the inner wall of the side steps due to the increase in volume during the epitaxial growth process, thereby reducing the risk of breakage due to small gaps at the adhesion points when the wafer is removed. In addition, for thick epitaxial processes, selecting a wafer (substrate) with a smaller diameter for epitaxial growth can effectively reduce the diameter of the epitaxial wafer.

[0018] 2. The method and apparatus for reducing the breakage rate of IGBT epitaxial wafers according to the present invention generate vibrations acting on the wafer by setting a separation component. The vibrations are transmitted to the wafer, causing the adhesion between the wafer and the support pad caused by the epitaxial growth process to gradually loosen and separate. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a top view of the base body and support plate in this invention; Figure 3 This is a schematic diagram of the wafer being placed inside the support disk in this invention; Figure 4 This is a schematic diagram of the support disk structure in this invention; Figure 5 This is a cross-sectional view of the support disk in this invention; Figure 6 yes Figure 5 Enlarged view of point A in the middle; Figure 7 yes Figure 5 Enlarged view at point B in the middle; Figure 8 This is a schematic diagram of the structure of the movable block, the limiting block, and the spring in this invention; Figure 9 This is a cross-sectional view of the base body in this invention.

[0021] In the diagram: 1. Base body; 2. Support plate; 3. Stop block; 4. Wafer; 5. Mounting slot; 6. Piezoelectric ceramic block; 7. Movable cavity; 8. Movable block; 9. Limiting block; 10. Pull rope; 11. Connecting channel; 12. Spring 1; 13. Cavity; 14. Movable plate; 15. Connecting block; 16. Through hole; 17. Air inlet pipe; 18. Vertical rod; 19. Spring 2; 20. Main pipe; 21. Branch pipe. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0023] Example 1: As Figure 1 As shown in the embodiment of the present invention, a method for reducing the breakage rate of IGBT epitaxial wafers includes the following steps: S1. Wafer mounting and positioning: Place the wafer 4 in the support plate 2 on the top of the base body 1 inside the epitaxial machine, and position the wafer 4 by the stop block 3 on the support plate 2. S2. Process Execution: Start and implement the epitaxial growth process; the epitaxial growth process is an existing technology and will not be described in detail here. Its function is to grow a specific material layer on the surface of wafer 4 to form an IGBT epitaxial wafer. S3. Active separation: After epitaxial growth is completed, the separation component set on the support disk 2 is activated, so that the separation component generates vibration acting on the wafer 4, so as to separate the wafer 4 from the adhesive part of the support disk 2.

[0024] like Figures 2 to 9 As shown, the present invention provides an apparatus for reducing the breakage rate of IGBT epitaxial wafers. This apparatus is applicable to the above-mentioned method for reducing the breakage rate of IGBT epitaxial wafers. In step S3, the separation component includes a piezoelectric ceramic block 6, which is embedded in a mounting groove 5 opened on the surface of the support disk 2.

[0025] During operation, the upper surface of the piezoelectric ceramic block 6 is flush with the bottom surface of the support disk 2 so that the wafer 4 can be placed stably on the support disk 2. When the separation component needs to be activated, an alternating voltage of a specific frequency is applied to the piezoelectric ceramic block 6. Under the action of the alternating voltage, the piezoelectric ceramic block 6 generates high-frequency vibration. This vibration is transmitted to the wafer 4, causing the adhesive parts between the wafer 4 and the support disk 2 caused by the epitaxial growth process to gradually loosen and separate.

[0026] Multiple baffles 3 are provided and evenly distributed on the inner wall of the support disk 2. During operation, the baffles 3 are used to position the wafer 4. During the placement of the wafer 4, the crystal orientation parts of the wafer 4 that are prone to breakage during epitaxial growth are oriented towards the gap between adjacent baffles 3. This prevents the wafer 4 from sticking to the inner wall of the side steps due to the increase in volume during epitaxial growth, thereby reducing the risk of breakage due to small gaps at the adhesion points when removing the wafer. In addition, for thick epitaxial processes, selecting a wafer 4 (substrate) with a smaller diameter for epitaxial growth can effectively reduce the diameter of the epitaxial wafer.

[0027] The piezoelectric ceramic block 6 is configured as a ring, and an air blowing component is connected to its central hole for introducing gas into the contact area between the wafer 4 and the support disk 2.

[0028] The air blowing assembly includes a cavity 13 disposed inside the support plate 2. The bottom of the cavity 13 is connected to an air inlet pipe 17, and its side is connected to the center hole of the piezoelectric ceramic block 6 through a connecting channel 11.

[0029] During operation, when the piezoelectric ceramic block 6 vibrates and loosens the adhesion between the wafer 4 and the support disk 2, the air blowing component is activated. External gas enters the cavity 13 through the air inlet pipe 17, then enters the center hole of the piezoelectric ceramic block 6 through the connecting channel 11, and finally blows towards the contact area between the wafer 4 and the support disk 2, further promoting the separation of the wafer 4 from the support disk 2. This reduces manual separation operations, lowers the risk of wafer 4 breakage, and improves production efficiency and product yield. In addition, when the airflow passes through the central hole of the piezoelectric ceramic block 6, it can simultaneously carry away... The heat generated by the piezoelectric ceramic block 6 during operation plays a certain role in cooling the piezoelectric ceramic block 6, which helps maintain the working stability and service life of the piezoelectric ceramic block 6.

[0030] A movable block 8 is movably disposed in the central hole of the piezoelectric ceramic block 6, and the upper end surface of the movable block 8 is flush with the upper end surface of the piezoelectric ceramic block 6 to block the central hole; a driving component is provided in the cavity 13 to drive the movable block 8 to move to open or close the central hole.

[0031] During operation, in the initial state, the movable block 8, the piezoelectric ceramic block 6, and the upper surface of the support plate 2 remain flush, thus ensuring that the wafer 4 can be placed stably. When the air blowing assembly needs to be activated, the drive assembly moves the movable block 8 downward, opening the central hole so that the gas can pass through smoothly and blow onto the contact area between the wafer 4 and the support plate 2. After the air blowing is completed, the movable block 8 is reset and the central hole is sealed again to maintain the flatness of the surface of the support plate 2. This ensures that the air blowing assembly can work normally when needed, without affecting the normal placement of the wafer 4 and the epitaxial growth process.

[0032] The drive assembly includes a movable plate 14, and a connecting block 15 is fixedly and slidably inserted into the air intake pipe 17 at the bottom of the movable plate 14; a pull rope 10 is connected to the side of the movable plate 14, and the other end of the pull rope 10 passes through the connecting channel 11 and is connected to the bottom of the movable block 8.

[0033] The piezoelectric ceramic block 6 has a movable cavity 7 on the inner wall of the central hole, and a limiting block 9 is provided on the side wall of the movable block 8. The limiting block 9 is limited to sliding within the movable cavity 7. A spring 12 is provided in the movable cavity 7 below the limiting block 9.

[0034] During operation, when an air blowing operation is required, air is supplied to the air inlet pipe 17 through an external air source. The airflow pushes the connecting block 15 and the movable plate 14 towards the center of the cavity 13. At the same time, the pull rope 10 pulls the movable block 8 towards the center hole of the piezoelectric ceramic block 6. When the movable block 8 moves into the range of the movable cavity 7, the connecting block 15 will completely move out of the range of the air inlet pipe 17. At this time, the airflow enters the cavity 13 through the air inlet pipe 17, then flows in from the bottom of the center hole through the connecting channel 11, passes through the movable cavity 7, and finally exits from the top of the center hole, blowing towards the contact area between the wafer 4 and the support disk 2. After the air blowing operation is completed, the air supply to the air inlet pipe 17 is stopped. Under the elastic force of the spring 12, the movable block 8 moves upward to reset and seals the center hole again. In addition, the movable block 8 can be limited by the limit block 9 to ensure that the movable block 8 can be accurately aligned with the center hole; at the same time, the limit block 9 is restricted inside the movable cavity 7, so that the movable block 8 is prevented from falling out of the center hole after each reset, and its top end can be kept flush with the upper surface of the support plate 2.

[0035] The movable plate 14 and the connecting block 15 have a through hole 16 at their center. A vertical rod 18 is slidably inserted through the through hole 16, and its top end is fixed to the top of the cavity 13. A second spring 19 is sleeved on the vertical rod 18. During operation, when air is supplied to the air inlet pipe 17 for blowing, the connecting block 15 and the movable plate 14 move towards the center of the cavity 13 under the push of the airflow. At this time, the vertical rod 18 slides in the through hole 16, which guides the movement of the movable plate 14 and the connecting block 15 and ensures the accuracy of their movement direction. At the same time, the second spring 19 is compressed. When the blowing operation is completed, the air supply to the air inlet pipe 17 is stopped. Under the rebound action of the second spring 19, the movable plate 14 and the connecting block 15 are pushed to move back to the direction of the air inlet pipe 17.

[0036] Example 2: Figure 2As shown in the comparative embodiment one, another embodiment of the present invention is as follows: multiple support plates 2 are provided, and each is embedded in the surface of the base body 1; a main pipe 20 is provided at the center of the base body 1, and the main pipe 20 is connected to the bottom of each support plate 2 through multiple branch pipes 21, and the air inlet pipe 17 at the bottom of each support plate 2 is correspondingly inserted into the branch pipe 21. During operation, multiple support disks 2 are evenly embedded on the surface of the base body 1, allowing multiple wafers 4 to undergo epitaxial growth processes simultaneously, thus improving production efficiency. When the air blowing assembly needs to be activated, external air enters through the main pipe 20, and then is delivered to the air inlet pipe 17 below the corresponding support disk 2 via each branch pipe 21. The air then enters the cavity 13 inside each support disk 2, and is finally blown from the central hole of the piezoelectric ceramic block 6 to the contact area between the wafer 4 and the support disk 2, enabling the simultaneous separation of multiple wafers 4 and further improving the automation and efficiency of the overall production process. Moreover, this centralized air supply method facilitates unified control and adjustment of parameters such as gas flow rate and pressure, ensuring consistent air blowing effects on each support disk 2, which is beneficial to improving the stability of product quality.

[0037] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on the perspective of the observer, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0038] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for reducing the breakage rate of IGBT epitaxial wafers, characterized in that: Includes the following steps: S1. Wafer positioning: Place the wafer (4) in the support plate (2) on top of the base body (1) inside the epitaxial machine, and position the wafer (4) by the stop block (3) on the support plate (2); S2. Process Execution: Start and implement the epitaxial growth process; S3. Active separation: After the epitaxial growth is completed, the separation component set on the support disk (2) is activated, so that the separation component generates vibrations that act on the wafer (4) to separate the wafer (4) from the adhesive part of the support disk (2).

2. An apparatus for reducing the breakage rate of IGBT epitaxial wafers, the apparatus being applicable to the method for reducing the breakage rate of IGBT epitaxial wafers as described in claim 1, characterized in that: The separation component in step S3 includes a piezoelectric ceramic block (6), which is embedded in the mounting groove (5) opened on the surface of the support plate (2).

3. The apparatus for reducing the breakage rate of IGBT epitaxial wafers according to claim 2, characterized in that: Multiple blocks (3) are provided and are evenly distributed on the inner wall of the support plate (2).

4. The apparatus for reducing the breakage rate of IGBT epitaxial wafers according to claim 3, characterized in that: The piezoelectric ceramic block (6) is configured as an annular shape, and an air blowing component is connected to its central hole for introducing gas into the contact area between the wafer (4) and the support disk (2).

5. The apparatus for reducing the breakage rate of IGBT epitaxial wafers according to claim 4, characterized in that: The air blowing assembly includes a cavity (13) disposed inside the support plate (2), the bottom of the cavity (13) is connected to an air inlet pipe (17), and its side is connected to the center hole of the piezoelectric ceramic block (6) through a connecting channel (11).

6. The apparatus for reducing the breakage rate of IGBT epitaxial wafers according to claim 5, characterized in that: A movable block (8) is movably disposed in the central hole of the piezoelectric ceramic block (6). The upper end face of the movable block (8) is flush with the upper end face of the piezoelectric ceramic block (6) to block the central hole. A driving component is provided in the cavity (13) to drive the movable block (8) to move to open or close the central hole.

7. The apparatus for reducing the breakage rate of IGBT epitaxial wafers according to claim 6, characterized in that: The drive assembly includes a movable plate (14), the bottom of which is fixed with a sealing sliding insertion block (15) inserted into the air intake pipe (17); a pull rope (10) is connected to the side of the movable plate (14), the other end of which passes through the connecting channel (11) and is connected to the bottom of the movable block (8).

8. The apparatus for reducing the breakage rate of IGBT epitaxial wafers according to claim 6, characterized in that: The piezoelectric ceramic block (6) has a movable cavity (7) on the inner wall of the central hole, and a limiting block (9) is provided on the side wall of the movable block (8). The limiting block (9) is limited to sliding within the movable cavity (7). A spring (12) is provided in the movable cavity (7) below the limiting block (9).

9. The apparatus for reducing the breakage rate of IGBT epitaxial wafers according to claim 7, characterized in that: The movable plate (14) and the connecting block (15) have a through hole (16) at their center. A vertical rod (18) is slidably inserted through the through hole (16) and its top end is fixed to the top of the cavity (13). A spring (19) is sleeved on the vertical rod (18).

10. The apparatus for reducing the breakage rate of IGBT epitaxial wafers according to claim 5, characterized in that: The support plate (2) is provided in multiple ways and is embedded in the surface of the base body (1); the base body (1) is provided with a main pipe (20) at its center, and the main pipe (20) is connected to the bottom of each support plate (2) through multiple branch pipes (21), and the air inlet pipe (17) at the bottom of each support plate (2) is inserted into the branch pipe (21).

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