Vacuum chuck device, vapor phase growth device and wafer processing method

Abstract

This invention discloses a vacuum chuck device, a vapor phase growth apparatus, and a wafer processing method. The vacuum chuck device includes: a base, comprising a support portion and a stepped portion; the upper surface of the support portion serves as a wafer support surface for supporting the wafer; the stepped portion is disposed below the support portion and extends radially outward along the support portion to form a stepped surface; and a cover ring, comprising a radially extending ring portion and a vertically extending ring portion connected to the radially extending ring portion. During the process, the radially extending ring portion shields the edge upper surface of the wafer, and the vertically extending ring portion is located above the stepped surface. The stepped portion exerts a downward force on the cover ring. This invention can reduce wafer warpage and improve the performance of the grown thin film.

Description

Vacuum chuck device, vapor phase growth device and wafer processing method This invention relates to the field of semiconductor equipment technology, and in particular to a vacuum chuck device, a vapor phase growth device, and a wafer processing method. In semiconductor manufacturing, vacuum chucks are often used as devices to support and hold wafers. When processing wafers using Chemical Vapor Deposition (CVD) / Atomic Layer Deposition (ALD) equipment, the wafer needs to be adsorbed onto the surface of a vacuum chuck device, and then heated by the vacuum chuck device to temperatures exceeding 400°C. In CVD / ALD equipment, the method of fixing wafers using a vacuum chuck device is easier to implement than the method of using an electrostatic chuck. However, because the shape of the wafer warps at high temperatures, it affects the performance of the vacuum chuck and the control of the wafer temperature. As shown in Figure 1, conventional vacuum chuck devices typically include a base 10, the upper surface of which is a wafer-bearing surface used to support the wafer W. Vacuum holes are formed on the wafer carrier surface, providing a vacuum adsorption pressure P1 to the back side of the wafer W. When the base 10 is raised to its highest position, a cover ring 2 surrounds the wafer W. The cover ring 2 includes a radially extending ring portion 20 and a vertically extending ring portion 21 connected thereto. The vertically extending ring portion 21 is located on the stepped surface of the base 10, and the gap G1 between the bottom of the vertically extending ring portion 21 and the stepped surface is 0 mm. Edge purging gas passages are formed on the stepped surface of the base 10 for purging the gap between the wafer W and the cover ring 2. When the base 10 is in the low position, the wafer W is introduced, and then the base 10 carries the wafer W to the high position, lifting the cover ring 2. During this process, due to the rapid increase in temperature, the upper and lower surfaces of the wafer W change from a flat state to a warped state. When the wafer W is in a flat state, there is a gap between the upper surface of the wafer W and the lower surface of the radially extending ring 20. As shown in Figure 2, as the warpage of the wafer W increases, the distance G2 between the upper surface of the wafer W and the lower surface of the radially extending ring 20 may gradually become 0 mm, or even lift the cover ring 2. As a result, on the one hand, the edge purging effect will be worse, and the edge purging gas will not be able to escape from the gap between the wafer W and the cover ring 2 or the flow rate will be severely lost. On the other hand, it will affect the process of growing thin films on the wafer, such as causing defects such as uneven film thickness. The purpose of this invention is to provide a vacuum chuck device, a vapor phase growth device, and a wafer processing method to reduce wafer warpage and improve the performance of the grown thin film. To achieve the above objectives, the present invention provides the following technical solution: A vacuum chuck device, applied within the cavity of a vapor phase growth apparatus, comprising: a base, the base including a support portion and a stepped portion, the upper surface of the support portion being a wafer support surface for supporting the wafer; the stepped portion being disposed below the support portion and extending radially outward along the support portion to form a stepped surface on the stepped portion; and a cover ring, the cover ring including a radially extending ring portion and a vertically extending ring portion connected to the radially extending ring portion; during the process, the radially extending ring portion shields the upper edge surface of the wafer, the vertically extending ring portion is located above the stepped surface, wherein the stepped portion can exert a downward force on the cover ring. Optionally, it further includes: a first vacuum via disposed on the wafer support surface; a first vacuum passage disposed inside the base and communicating with the first vacuum via, for applying a first vacuum pressure P1 to the back side of the wafer to adsorb and fix the wafer; a second vacuum via disposed on the stepped surface of the base, located below the vertically extending ring; and a second vacuum passage disposed inside the base and communicating with the second vacuum via, for applying a second vacuum pressure P2 to the bottom surface of the vertically extending ring to apply a downward force to the cover ring. Optionally, the vapor phase growth apparatus further includes a vacuum channel for evacuating the interior of the cavity at a third vacuum pressure P, wherein the first vacuum pressure P1 is greater than the third vacuum pressure P. Optionally, the bottom of the vertically extending ring is provided with an upwardly recessed annular groove. Optionally, the cross-sectional shape of the annular groove can be any one of a rectangle, a triangle, or a semicircle. Optionally, the base has a groove on its stepped surface and the bottom of the vertically extending ring has a downwardly protruding part; the protruding part matches the groove. Optionally, the cross-section of the protrusion is triangular, and the cross-section of the groove is triangular; and the apex angle of the cross-section of the protrusion is greater than the apex angle of the cross-section of the groove. Optionally, the first vacuum path and the second vacuum path are interconnected, and the second vacuum pressure P2 is equal to the first vacuum pressure P1. Optionally, it further includes: a coil disposed within the stepped portion of the base and located below the stepped surface, through which direct current is applied, and the coil electrostatically attracts the covering ring. Optionally, it further includes: an edge purge gas through-hole, which is formed on the stepped surface of the base and located on the inner side of the lower surface of the vertical extension in the horizontal direction; an edge purge gas passage communicating with the edge purge gas through-hole; and a purge through-hole, which is disposed on the radially extending ring portion for introducing purge gas from the gap between the base and the cover ring into the cavity. Optionally, the purge through-hole is one or any combination of an external oblique hole, a vertical hole, and an internal oblique hole. Optionally, it further includes: a support shaft, one end of which is disposed at the bottom of the base, and the other end passing through the bottom of the cavity and connected to an external drive device. The first vacuum passage, the second vacuum passage, and the edge purge air passage are led out to the outside of the cavity through the inside of the support shaft. On the other hand, the present invention also provides a vapor phase growth apparatus, comprising: a cavity; a gas spray head disposed at the top of the cavity for introducing process gas into the cavity; and a vacuum suction cup device as described above, disposed inside the cavity and disposed opposite to the gas spray head. Optionally, it further includes: an air extraction ring disposed on the radial periphery of the base; the air extraction ring has an annular air extraction channel inside for extracting air from the cavity. In another aspect, the present invention also provides a method for processing a wafer using the vapor phase growth apparatus described above, comprising: when the base is in a low position, placing the wafer on the wafer support surface of the base; applying a first vacuum pressure P1 to the back side of the wafer to adsorb and fix the wafer on the wafer support surface; when the base is raised to a high position, applying a downward force to the cover ring, causing the vertically extending ring portion to contact the stepped surface. The present invention has the following beneficial effects: The present invention applies a downward force to the cover ring by the base, causing the cover ring to move downward, stretching the edge of the warped wafer toward the wafer bearing surface, thereby reducing the warpage of the wafer and improving the performance of the grown film. Specifically, a second vacuum pressure P2 is applied to the bottom surface of the vertically extending ring through a second vacuum passage and a second vacuum through-hole on the base. This causes the vertically extending ring of the cover ring to move towards the stepped surface of the base. Alternatively, a coil can be installed on the base to electrostatically attract the cover ring, thereby applying a downward force to the edge of the wafer and reducing its warpage. As the wafer warpage gradually decreases, the adsorption effect of the first vacuum pressure P1 on the back edge of the wafer gradually increases, further flattening the edge of the wafer. This is a superposition effect of vacuum adsorption and physical clamping. The present invention also achieves the following: by setting an edge purging gas path and an edge purging gas through hole in the cover ring, the gap between the wafer and the cover ring is purged; and by introducing the purging gas between the wafer and the cover ring into the cavity through the provided purging through hole, the edge region of the wafer is purged when the second spacing G2 is 0. The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the vacuum chuck device, vapor phase growth apparatus, and wafer processing method proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the drawings for a clearer understanding of the objectives, features, and advantages of this invention. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to enable those skilled in the art to understand and read them. They are not intended to limit the implementation conditions of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention. The present invention applies a downward force to the cover ring by the base, causing the cover ring to move downward and stretching the edge of the warped wafer toward the wafer bearing surface, thereby reducing the warpage of the wafer and solving the problem of wafer warpage. The present invention will be described in detail below with reference to specific embodiments to provide a better understanding of the invention. As shown in Figure 3, this embodiment provides a vacuum chuck device, including: a base 100, the upper surface of which is a wafer carrier surface for carrying a wafer W; and a cover ring 200, which surrounds the wafer W when the base 100 is raised to the process position. The cover ring 200 includes a radially extending ring portion 201 and a vertically extending ring portion 202 connected thereto; in this embodiment, the radial cross-section of the right side portion of the cover ring 200 is inverted L-shaped, and the left side portion is symmetrical to the right side portion. In this embodiment, the base 100 includes a support portion 101 and a stepped portion 102. The top surface of the support portion 101 is the wafer support surface. The stepped portion 102 extends radially outward along the support portion 101 to form a stepped surface on the top surface of the stepped portion 102. Preferably, the stepped surface is lower than the wafer support surface. In some embodiments, the stepped surface is annular. The vertically extending ring 202 is disposed above the stepped surface of the base 100, and the end of the radially extending ring 201 is located above the edge of the wafer W. During the process, the radially extending ring 201 covers the upper surface of the edge of the wafer W, and the vertically extending ring 202 is located above the stepped surface. The stepped portion 102 can exert a downward force on the covering ring 200. Referring to Figure 3, when the wafer W is not warped, there is a second distance G2 between the bottom surface of the radially extending ring portion 201 and the upper surface of the wafer W. After the wafer W warps, the warped wafer W pushes up the covering ring 200, and there is a first distance G1 between the bottom of the vertically extending ring portion 202 and the stepped surface, where G1 > 0. Referring to Figure 3, the vacuum chuck device further includes: a first vacuum through-hole, which is formed on the wafer carrier surface; and a first vacuum passage 110, which is disposed inside the base 100 and communicates with the first vacuum through-hole, for applying a first vacuum pressure P1 to the back side of the wafer W to adsorb and fix the wafer W. In this embodiment, the first vacuum through-hole and the first vacuum passage 110 may be integrally formed. A second vacuum via is disposed on the stepped surface of the base 100, below the vertically extending ring portion 202; a second vacuum passage 130 is disposed inside the base 100 and communicates with the second vacuum via, for applying a second vacuum pressure P2 to the bottom surface of the vertically extending ring portion 202 to exert a downward force on the edge of the wafer W. In this embodiment, the second vacuum via and the second vacuum passage 130 may be integrally formed. In some embodiments, the first vacuum pressure P1 is greater than the second vacuum pressure P2. As shown in Figure 4, when the wafer W is heated, the warpage of the wafer W will become more and more severe as the temperature increases, and it may come into contact with the radially extended ring portion 201 of the cover ring 200 and lift the cover ring 200, that is, the second spacing G2 is 0. To reduce the warpage of wafer W, a downward force is applied to the vertically extending ring 202. This downward force, combined with the gravity of the covering ring 200, causes the radially extending ring 201 to move downwards, reducing the first gap G1. This applies a downward force to the warped wafer edge until the first gap G1 reaches zero. As the wafer warpage gradually decreases, the adsorption effect of the first vacuum pressure P1 on the back edge of the wafer gradually increases, further flattening the wafer edge. This is a combined effect of vacuum adsorption and physical clamping. Please continue to refer to Figure 3 or Figure 4. This embodiment also includes: an edge purging gas through hole, which is opened on the stepped surface of the base 100, located between the inner side of the cover ring 200 and the outer side of the support part 101. An edge purge gas passage 120, connected to the edge purge gas through-hole, is used to introduce purge gas into the edge purge gas passage 120, wherein the pressure of the purge gas is P0. This purges the gap between the wafer W and the cover ring 200. In this embodiment, the edge purge gas through-hole and the edge purge gas passage 120 are integrated. As shown in Figure 5, this embodiment also includes a support shaft 300, one end of which is fixedly connected to the bottom of the base 100, and the other end passes through the bottom of the cavity of the vapor phase growth device and is connected to an external driving device. The driving device can drive the support shaft 300 to rotate and drive the vacuum suction cup device on the support shaft 300 to move between a low position and a high position. The first vacuum passage 110, the second vacuum passage 130 and the edge purge passage 120 are led out to the outside of the cavity through the inside of the support shaft 300. The first vacuum passage 110 can be connected to a first vacuum pump outside the cavity. The first vacuum pump evacuates the inside of the first vacuum passage 110, so that a vacuum adsorption force of pressure P1 is applied to the back side of the wafer W to adsorb and fix the wafer W on the wafer support surface. The second vacuum passage 130 is also connected to the second vacuum pump outside the cavity. The second vacuum pump evacuates the interior of the second vacuum passage 130, so that a vacuum adsorption force of pressure P2 is applied to the bottom of the vertical extension ring 202. After the vertical extension ring 202 is adsorbed onto the stepped surface of the base 100, the radial extension ring 201 of the cover ring 200 pulls the warped edge of the wafer W closer to the wafer mounting surface, thereby reducing the warpage of the wafer W. When the warpage of the wafer W is reduced to a certain value, the warped wafer W can be adsorbed and fixed on the wafer mounting surface by the action of the first vacuum pressure P1, so that the upper surface of the wafer W is infinitely close to a flat state. The edge purging air passage 120 is connected to an external purging air source, which provides purging gas to the interior of the edge purging air passage 120. As shown in Figures 6-8, this embodiment also includes a purge through-hole 210, which is disposed on the radially extending ring portion 201, for introducing purge gas from the gap between the base 100 and the cover ring 200 into the cavity. This further facilitates the reduction of the warpage of the wafer W and helps the wafer W to be adsorbed and fixed on the wafer mounting surface. As shown in Figure 6, in other embodiments, the purge through hole 210 is an externally inclined hole, that is, a plurality of purge through holes 210 in the shape of externally inclined holes are provided at intervals on the radially extending ring portion 201 along the circumference of the covering ring 200. As shown in Figure 7, in other embodiments, the purge through-hole 210 is a vertical hole, that is, a plurality of purge through-holes 210 in the form of vertical holes are provided at intervals on the radially extending ring portion 201 along the circumference of the covering ring 200. As shown in Figure 8, in other embodiments, the purge through hole 210 is an inwardly oblique hole, that is, a plurality of purge through holes 210 in the shape of inwardly oblique holes are provided at intervals on the radially extending ring portion 201 along the circumference of the covering ring 200. It is understood that in some other embodiments, the purge through-hole 210 can be configured as any combination of an externally inclined hole, a vertical hole, and an internally inclined hole as needed. The configuration of the purge through-hole 210 can solve the problem that when the wafer is warped and there is no gap between it and the radially extending ring portion 201 of the cover ring 200, the purge air path is blocked, making it difficult to adsorb and fix the wafer, and in severe cases, causing mechanical damage to the wafer; it can also enable the top of the radially extending ring portion 201 to be purged. Please continue to refer to Figures 6 and 7. In this embodiment or some other embodiments, the bottom of the vertically extending ring portion 202 is provided with an upwardly recessed annular groove 220. The annular groove 220 can enhance the adsorption effect of the covering ring, ensuring that even when the covering ring is pulled to the bottom, i.e., when the first gap G1=0, a stable second vacuum pressure P2 can still be obtained. Specifically, as shown in Figure 6, the cross-sectional shape of the annular groove 220 can be rectangular. As shown in Figure 7, the cross-sectional shape of the annular groove 220 can be semi-circular. In some other embodiments, the cross-sectional shape of the annular groove 220 can also be triangular, but the present invention is not limited thereto. As shown in Figure 8, in some other embodiments, the bottom of the vertically extending ring 202 has a downwardly protruding protrusion 230; the stepped surface of the base 100 has a groove 140, and the protrusion 230 matches the groove 140. The cross-section of the protrusion 230 is triangular, and the cross-section of the groove 140 is triangular. In this embodiment, the apex angle of the cross-section of the protrusion 230 is greater than the apex angle of the cross-section of the groove 140. That is, when the protrusion 230 is adsorbed into the groove 140, the inclined surface of the protrusion 230 preferentially contacts the top side of the groove 140, while the tip of the protrusion 230 does not contact the bottom of the groove 140, forming a certain sealing gap, which is beneficial for downward adsorption and fixation of the vertically extending ring 202. Furthermore, this arrangement ensures the alignment of the cover ring 200 and the base 100. As shown in Figure 8, the second vacuum through hole communicates with the bottom of the groove portion 140. Alternatively, as shown in Figure 9, the second vacuum through hole communicates with the side of the groove portion 140. Please continue referring to Figures 9 and 10. The first vacuum passage 110 and the second vacuum passage 130 are interconnected, and the second vacuum pressure P2 is equal to the first vacuum pressure P1. That is, by simultaneously applying the first vacuum pressure P1 to the bottom of the vertically extending ring 202 and the back surface of the wafer W, the radially extending ring 201 of the cover ring 200 continuously applies a downward force to the edge of the wafer W, thereby suppressing the warping of the edge of the wafer W. In some other embodiments, in order to apply a downward force to the vertically extending ring 202 and reduce the warpage of the edge of the wafer W, this embodiment can achieve this by applying an electrostatic adsorption force to the vertically extending ring 202. Specifically, the vacuum chuck device includes a coil disposed within the stepped portion 102 of the base 100 and located below the stepped surface. A direct current is passed through the coil, and the coil electrostatically adsorbs the covering ring 200. As shown in Figure 11, this embodiment also provides a vapor phase growth apparatus, including: a cavity 400, a gas spray head 500 disposed at the top of the cavity 400 for introducing process gas 501 into the cavity 400; and a vacuum suction cup device as described above disposed inside the cavity 400, opposite to the gas spray head 500. The support shaft 300 of the vacuum chuck device passes through the bottom of the cavity of the vapor phase growth device and is connected to an external drive device (not shown in Figure 11). The drive device can drive the support shaft 300 to rotate, thereby causing the base 100 to rotate. The drive device can also be used to drive the base 100 on the support shaft 300 to move vertically between a low position and a high position within the cavity 400. When processing wafer W, the base 100 is driven to move wafer W to a high position. When wafer W needs to be picked up or put down, the base 100 is driven to move wafer W back to a low position. The cover ring 200 is supported from below by a support device below the gas spray head 500 and is located in a preset position. When the base 100 is in the high position, the cover ring 200 is lifted by the base 100 or by the warped wafer. Referring to Figure 11, the vapor phase growth apparatus further includes a vacuum ring 600 and a third vacuum pump (not shown in Figure 11), which are disposed between the gas spray head 500 and the top of the cavity 400. When the base 100 is in a high position, the vacuum ring 600 surrounds the base 100. An annular vacuum channel 610 is provided inside the vacuum ring 600, and the third vacuum pump is connected to the vacuum channel 610 to apply a third vacuum pressure P to evacuate the cavity 400. A cover ring 510 is provided between the vacuum ring 600 and the gas spray head 500. The present invention also provides a method for processing a wafer using the vapor phase growth apparatus described above, comprising: placing a wafer W on the wafer support surface of the base 100 when the base 100 is in a low position; and applying a first vacuum pressure P1 to the back side of the wafer W to adsorb and fix the wafer W on the wafer support surface. The base 100 is driven to rise to a high position, and the base 100 applies a downward force to the covering ring 200, causing the vertically extending ring portion to contact the stepped surface. During the process of the base 100 being fed in and rising to a high position, the wafer W is constantly heated, causing the edges of the wafer W to warp. A second vacuum pressure P2 is applied to the bottom of the vertically extending ring, and the radially extending ring of the covering ring 200 begins to press the edges of the wafer downward, reducing the warpage of the wafer until the first spacing G1 = 0 (theoretically). In principle, it is impractical to completely flatten the warped wafer. In the process, the warpage is generally controlled within the range of 0-0.1 mm, which can be achieved in this embodiment by controlling the first spacing G1 and the second spacing G2. The relatively small value of the first spacing G1 determines that the second vacuum pressure P2 does not need to be too high. This is because for wafer W to be adsorbed and fixed, the second vacuum pressure P2 needs to be less than the third vacuum pressure P to ensure that the process gas flow transmitted from the gas spray head is not sucked away from the second vacuum path, but rather that most of it is sucked away by the suction ring. In this way, it is also possible to avoid contamination of the corresponding vacuum path (e.g., the second vacuum path) inside the base due to dirty process gas. This embodiment also includes blowing the gap between the wafer and the cover ring through the provided edge blowing gas path and edge blowing gas through hole; and introducing the blowing gas between the wafer and the cover ring into the cavity through the provided blowing through hole, so as to blow the edge region of the wafer when the second spacing G2 is 0. On the other hand, since the first vacuum path is the main vacuum path, it needs to draw a large area of ​​vacuum from the back of the wafer to ensure the wafer's adsorption and fixation effect. During the dynamic process of the warped wafer edge, sufficient first vacuum pressure P1 needs to be applied to the back of the wafer so that the first vacuum pressure P1 can quickly flatten the back of the wafer and its edge. Therefore, under normal circumstances, the second vacuum pressure P2 needs to be set < the third vacuum pressure P. Under the action of the cover ring, the warped wafer gradually approaches the flat wafer, thereby making the gap between the back of the wafer and the wafer mounting surface smaller and smaller, making it easier and more stable to maintain the vacuum force of the first vacuum pressure P1. It is understood that in some other embodiments, when the first vacuum path and the second vacuum path are interconnected, the first vacuum pressure P1 is equal to the second vacuum pressure P2. The vacuum adsorption force applied to the vertically extending ring when the first vacuum path and the second vacuum path are interconnected can be achieved by applying the first vacuum pressure P1 after placing the wafer on the wafer cross-section of the base when the base is in a low position. Under the action of the first vacuum pressure P1, while adsorbing and fixing the wafer, the second vacuum path is evacuated. When the base rises to a high position, it can directly provide a downward force to the vertical extension ring, causing the vertical extension ring to move downward and stretch the edge of the wafer. As a result, the gap between the back of the wafer and the wafer mounting surface becomes smaller and smaller. During this process, the first vacuum pressure P1 has the ability to quickly flatten the back of the wafer and the edge. Maintaining the vacuum force of the first vacuum pressure P1 becomes easier and more stable. When the second vacuum pressure P2 is equal to the first vacuum pressure P1, it can also ensure that the process airflow transmitted from the gas spray head is not sucked away from the second vacuum path, but is mostly sucked away by the evacuation ring. In some other embodiments, the wafer warpage is reduced by placing a coil in the stepped portion and passing a direct current through the coil to apply an adsorption force to the bottom of the vertically extending ring portion. In summary, the present invention applies a downward force to the cover ring by the base, causing the cover ring to move downward and stretching the edge of the warped wafer toward the wafer bearing surface, thereby reducing the warpage of the wafer and improving the performance of the grown film. This invention applies a second vacuum pressure P2 to the bottom surface of the vertically extending ring through a second vacuum passage and a second vacuum through-hole. This pressure adsorbs the vertically extending ring of the covering ring, causing it to move towards the stepped surface of the base. This, in turn, applies a downward force to the edge of the wafer, reducing its warpage. As the wafer warpage gradually decreases, the adsorption effect of the first vacuum pressure P1 on the back edge of the wafer gradually increases, further flattening the wafer edge. This is a combined effect of vacuum adsorption and physical clamping. This invention purges the gap between the wafer and the cover ring by setting an edge purging gas path and an edge purging gas through hole; and introduces the purging gas between the wafer and the cover ring into the cavity through the purging through hole, so that when the second spacing G2 is 0, the edge area of ​​the wafer is purged, avoiding by-product deposition and contamination. It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the drawings and are only for the convenience of describing the 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, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature. Although the present invention has been described in detail through the preferred embodiments described above, it should be understood that the foregoing description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the foregoing. Therefore, the scope of protection of the present invention should be defined by the appended claims. 10: Base 2: Covering ring 20: Radial extending ring 21: Vertical extending ring G1: Gap G2: Distance P0: Pressure of purge gas P1: Vacuum adsorption pressure W: Wafer 100: Base 101: Supporting part 102: Stepped part 110: First vacuum passage 120: Edge purge gas passage 130: Second vacuum passage 140: Groove part 200: Covering ring 201: Radial extending ring 202: Vertical extending ring 210: Purge through hole 220: Ring groove 230: Protrusion 300: Support shaft 400: Cavity 500: Gas spray head 501: Process gas 510: Cover ring 600: Vacuum ring 610: Vacuum channel G1: First gap G2: Second gap P1: First vacuum pressure P2: Second vacuum pressure P: Third vacuum pressure Figure 1 is a schematic diagram of the structure of a vacuum chuck device after placing a wafer on it, as provided in the prior art; Figure 2 is a schematic diagram of the structure of a wafer placed on a vacuum chuck device after warping, as provided in the prior art; Figure 3 is a schematic diagram of the main structure of a vacuum chuck device provided in the first embodiment of the present invention; Figure 4 is a schematic diagram of the structure of a vacuum chuck device provided in the first embodiment of the present invention when suppressing wafer warping; Figure 5 is a schematic diagram of the vacuum path and purge gas path in the vacuum chuck device provided in the first embodiment of the present invention; Figure 6 is a schematic diagram of the main structure of a vacuum chuck device provided in the second embodiment of the present invention; Figure 7 is a schematic diagram of the main structure of a vacuum chuck device provided in the third embodiment of the present invention; Figure 8 is a schematic diagram of the main structure of a vacuum chuck device provided in the fourth embodiment of the present invention; Figure 9 is a schematic diagram of the main structure of a vacuum chuck device provided in the fifth embodiment of the present invention; Figure 10 is a schematic diagram of the main structure of a vacuum chuck device provided in the sixth embodiment of the present invention; Figure 11 is a schematic diagram of the main structure of a vapor phase growth apparatus provided by the present invention. 100: Base 101: Bearing section 102: Step section 110: First vacuum path 120: Edge purge air path 130: Second vacuum path 200: Coverage Ring 201: Radial extension ring 202: Vertical extension ring G1: First spacing G2: Second spacing P0: Pressure of the purging gas P1: First vacuum pressure P2: Second vacuum pressure W: Wafer

Claims

1. A vacuum chuck device, used within the cavity of a vapor phase growth apparatus, characterized in that it comprises: A base, comprising a support portion and a stepped portion, wherein the upper surface of the support portion is a wafer support surface for supporting a wafer; the stepped portion is disposed below the support portion and extends radially outward along the support portion to form a stepped surface on the stepped portion; a first vacuum through-hole is disposed on the wafer support surface; a first vacuum passage is disposed inside the base and communicates with the first vacuum through-hole, for applying a first vacuum pressure P1 to the back side of the wafer to adsorb and fix the wafer; a cover ring, comprising a radially extending ring portion and a vertically extending ring portion connected to the radially extending ring portion; a second vacuum through-hole is disposed on the stepped surface of the base, located below the vertically extending ring portion; a second vacuum passage is disposed inside the base and communicates with the second vacuum through-hole; During the process, the radially extending ring portion shields the upper surface of the wafer edge, and the vertically extending ring portion is located above the step surface. The step portion can apply a second vacuum pressure P2 to the bottom surface of the vertically extending ring portion through the second vacuum air path and the second vacuum through hole to apply a downward force to the cover ring.

2. The vacuum suction cup device as claimed in claim 1, wherein, The vapor phase growth apparatus further includes a vacuum channel for evacuating the interior of the cavity with a third vacuum pressure P, wherein the first vacuum pressure P1 is greater than the third vacuum pressure P.

3. The vacuum suction cup device as claimed in claim 1, wherein, The bottom of the vertically extending ring is provided with an upwardly recessed annular groove.

4. The vacuum suction cup device as claimed in claim 3, wherein, The cross-sectional shape of the annular groove can be any one of a rectangle, a triangle, or a semicircle.

5. The vacuum suction cup device as claimed in claim 1, wherein, The base has a groove on its stepped surface, and the bottom of the vertically extending ring has a downward protrusion; the protrusion matches the groove.

6. The vacuum suction cup device as claimed in claim 5, wherein, The cross-section of the protrusion is triangular, and the cross-section of the groove is triangular; and the apex angle of the cross-section of the protrusion is greater than the apex angle of the cross-section of the groove.

7. The vacuum suction cup device as claimed in claim 1, wherein, The first vacuum path and the second vacuum path are interconnected, and the second vacuum pressure P2 is equal to the first vacuum pressure P1.

8. The vacuum suction cup device as claimed in claim 1, wherein, It also includes: a coil disposed within the stepped portion of the base and located below the stepped surface, through which direct current is passed, and the coil is electrostatically attracted to the covering ring.

9. The vacuum chuck device as claimed in any one of claims 1 to 8, wherein, It also includes: an edge purge gas through-hole, which is formed on the stepped surface of the base and located on the inner side of the lower surface of the vertical extension in the horizontal direction; an edge purge gas passage, which communicates with the edge purge gas through-hole; and a purge through-hole, which is provided on the radial extension ring for introducing purge gas from the gap between the base and the cover ring into the cavity.

10. The vacuum suction cup device as claimed in claim 9, wherein, The purging through-hole is one or any combination of external oblique holes, vertical holes, and internal oblique holes.

11. The vacuum suction cup device as claimed in claim 10, wherein, It also includes: a support shaft, one end of which is located at the bottom of the base and the other end passes through the bottom of the cavity and is connected to an external drive device; a first vacuum air passage, a second vacuum air passage and the edge purging air passage are led out to the outside of the cavity through the inside of the support shaft.

12. A vapor phase growth apparatus, characterized in that it comprises: A cavity, with a gas spray head disposed at the top of the cavity, for introducing process gas into the cavity; The vacuum suction cup device as described in any one of claims 1 to 11 is disposed inside the cavity and positioned opposite to the gas spray head.

13. The vapor phase growth apparatus as claimed in claim 12, wherein, It also includes: an air extraction ring, which is disposed on the radial periphery of the base; the air extraction ring has an annular air extraction channel inside for extracting air from the cavity.

14. A method for processing a wafer using a vapor phase growth apparatus as described in claim 13, characterized in that it comprises: When the base is in the low position, the wafer is placed on the wafer support surface of the base; a first vacuum pressure P1 is applied to the back side of the wafer to adsorb and fix the wafer on the wafer support surface; when the base is raised to the high position, the base applies a downward force to the cover ring, so that the vertically extending ring contacts the stepped surface.

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