Hydrostatic pads, polishing equipment, and silicon wafers

Abstract

Embodiments of the present disclosure disclose a static pressure pad, a polishing machine, and a silicon wafer, wherein the static pressure pad is used to clamp both sides of the silicon wafer in pairs in a silicon wafer double-sided polishing machine, and the static pressure pad comprises: a base having a fixed plane facing the silicon wafer; a plurality of static pressure blocks uniformly distributed along a direction perpendicular to the fixed plane and protruding from the fixed plane, providing static pressure to the silicon wafer through a fluid to support one side of the silicon wafer non-contactually; and a driving module configured to drive each static pressure block to move along a direction perpendicular to the fixed plane when the first plane formed by the end of each static pressure block is not parallel to the target plane where the silicon wafer is located, so that the first plane becomes parallel to the target plane.

Description

Technology Field

[0001] [Reference to related applications]

[0002] The present disclosure claims priority to application No. 202310340170.3, filed with the Chinese Intellectual Property Office on March 31, 2023, and incorporates the entire contents thereof by reference into the present application.

[0003] The present disclosure relates to the field of semiconductor manufacturing technology, and in particular to a static pressure pad, a polishing device, and a silicon wafer. Background Technology

[0004] The semiconductor silicon wafer production process generally includes processing steps such as growing, wire cutting, grinding, and polishing. Double-sided grinding is a single grinding process used to simultaneously grind two major surfaces of a silicon wafer to ensure the wafer has a very flat surface. During the double-sided grinding process, it is necessary to fix the silicon wafer using a dedicated device so that the grinding wheel can simultaneously grind the two major surfaces of the silicon wafer. Typically, such a fixing device includes a pair of opposing hydrostatic bearings, and the silicon wafer is installed between the two hydrostatic bearings along the longitudinal direction. The hydrostatic bearings form a fluid barrier between themselves and the major surfaces of the silicon wafer, allowing the silicon wafer to stand upright without contacting the two hydrostatic bearings, while simultaneously grinding the two major surfaces of the silicon wafer using the opposing grinding wheels. Compared to physical clamping, the fluid clamping method of hydrostatic bearings reduces damage to the silicon wafer and allows the silicon wafer to move (rotate) with less friction in the tangential direction compared to the hydrostatic bearing surfaces.

[0005] In a double-sided polishing machine, the angles of a pair of opposing polishing wheels must be adjusted to correct the flatness of the silicon wafer. During the process of adjusting the polishing wheels, if the deflection angle of the left and right pair of polishing wheels is too large, the silicon wafer tilts when the polishing wheels come into direct contact with the silicon wafer, or tilts due to mechanical structural instability when the silicon wafer is fixed using the aforementioned dedicated device. In this case, since the gap between the pair of static pressure supports is fixed and the distance between the static pressure support on one side and the silicon wafer is fixed, the silicon wafer comes into contact with the static pressure support, causing friction between the silicon wafer and the static pressure support, which can worsen the flatness of the silicon wafer and even cause fragmentation.

[0006] After polishing is completed, the silicon wafer is unloaded by contacting a static pressure support via an unloading device. A dedicated device for fixing the silicon wafer is driven to move the silicon wafer until it contacts the static pressure support, and one side of the silicon wafer in contact with the static pressure support is adsorbed and fixed by the support. If processing residue is sputtered onto the static pressure support during the processing process or if the cleanliness of the silicon wafer surface is poor, the silicon wafer surface becomes contaminated when it contacts the support, resulting in a large number of pit-shaped defects appearing on the silicon wafer surface.

[0007] To solve the aforementioned technical problem, the embodiment of the present application provides a static pressure pad, a polishing device, and a silicon wafer. By changing the configuration of the static pressure pad in real time during a double-sided polishing process to adjust the gap between the static pressure pad and the silicon wafer, the stability of the polishing process is ensured and product quality is improved. At the same time, the surface damage to the silicon wafer is improved by reducing the area where the static pressure pad adsorbs the silicon wafer.

[0008] The technical solution of the present application is implemented as follows:

[0009] In a first aspect, the present application provides a static pressure pad, said static pressure pad is used to clamp both sides of a silicon wafer in pairs in a silicon wafer double-sided polishing machine, said static pressure pad comprises: a base having a fixed plane facing the silicon wafer; a plurality of static pressure blocks uniformly distributed along a direction perpendicular to the fixed plane and protruding from the fixed plane, providing static pressure to the silicon wafer through a fluid to support one side of the silicon wafer non-contactually; and a driving module configured to drive each static pressure block to move along a direction perpendicular to the fixed plane when the first plane formed by the end of each static pressure block is not parallel to the target plane where the silicon wafer is located, so that the first plane becomes parallel to the target plane.

[0010] Optionally, the static pressure pad further comprises a support block installed on the fixed plane, the support block may move along a direction perpendicular to the fixed plane and protrude from the fixed plane, and the support block is configured such that the protrusion height of the support block relative to the fixed plane is greater than the protrusion height of any one of the plurality of static pressure blocks.

[0011] Optionally, a plurality of adsorption holes are installed at the end of the support block, and the adsorption holes are configured to adsorb the silicon wafer through a vacuum.

[0012] Optionally, the static pressure pad further includes a sensor and a controller, the sensor is used to detect the spatial position of the target plane, the controller transmits a control signal to the driving module based on the spatial position of the target plane, and the driving module drives the movement of the plurality of static pressure blocks according to the control signal so that the first plane is parallel to the target plane.

[0013] Optionally, the sensor is a pressure sensor, and the pressure sensor is used to detect changes in the silicon wafer subjected to the static pressure to obtain the spatial orientation of the silicon wafer.

[0014] Optionally, the sensor is a distance sensor, and the distance sensor is used to detect the distance between the silicon wafer and the first plane to obtain the spatial orientation of the silicon wafer.

[0015] Optionally, a plurality of via holes are installed at the end of each static pressure block, and the via holes are configured to allow the fluid to flow out and support the silicon wafer in a non-contact manner.

[0016] Optionally, the drive module includes a hydraulic drive unit or a pneumatic drive unit for driving the movement of the static pressure block.

[0017] In a second aspect, the present application provides a polishing device, said polishing device for polishing both sides of a silicon wafer, said polishing device comprising: a carrier for supporting said silicon wafer along a vertical direction; two polishing wheels symmetrically installed with respect to said carrier; and two of the above-described hydrostatic pads symmetrically installed with respect to said carrier.

[0018] In a third aspect, the present application provides a silicon wafer, said silicon wafer is obtained using the polishing apparatus described above.

[0019] Embodiments of the present application provide a static pressure pad, a polishing device, and a silicon wafer. The static pressure pad comprises a base, a plurality of static pressure blocks extendable and retractable to protrude from the surface of the base, and a driving module for driving the movement of the static pressure blocks. A first plane formed by the ends of the plurality of static pressure blocks is used to fix the silicon wafer by providing static pressure to the silicon wafer. The static pressure pad can change the spatial position of the first plane by adjusting the extension and retraction lengths of the plurality of static pressure blocks according to the target plane where the silicon wafer is located, thereby making the first plane and the target plane parallel. Thus, when the silicon wafer is significantly tilted, the static pressure pad is ensured not to come into contact with the silicon wafer, thereby avoiding a situation in which fragmentation and / or damage to the static pressure pad occurs. Additionally, damage to the back surface of the silicon wafer is improved by reducing the adsorption area of ​​the static pressure pad on the silicon wafer through a support block. Brief explanation of the drawing

[0020] FIG. 1 is a structural schematic diagram of a vertical grinding machine among related technologies; FIG. 2 is a structural schematic diagram of a polishing pad of an embodiment of the present application; FIG. 3 is a schematic diagram of clamping a tilted silicon wafer using a polishing pad of an embodiment of the present application; FIG. 4 is a schematic diagram of the shape of a polishing pad of an embodiment of the present application. Specific details for implementing the invention

[0021] The technical solution in the embodiment of the present application will be explained clearly and completely below by associating it with the drawings of the embodiment of the present application.

[0022] As the diameter of silicon wafers increases while the characteristic size of integrated circuits decreases, the requirements for the flatness and cleanliness of the silicon wafer surface increase, and at the same time, the requirements for the degree of surface damage of the silicon wafer also increase. Double-sided polishing refers to the process of polishing both sides of a silicon wafer simultaneously to produce a wafer with a very flat surface. During double-sided polishing using a vertical polishing machine, a silicon wafer clamping device must be used to maintain the upright position of the silicon wafer. The clamping device generally includes a pair of fluid hydrostatic pads, and the pair of fluid hydrostatic pads are configured to support the silicon wafer in a non-contact manner by simultaneously applying fluid pressure to the two sides of the silicon wafer placed between them. Among the vertical polishing machines, the polishing device for polishing the silicon wafer includes a pair of opposing polishing wheels, and when the silicon wafer is supported by the pair of polishing wheels, the pair of polishing wheels simultaneously polish the two sides of the silicon wafer along a predetermined polishing path.

[0023] When performing double-sided polishing on a silicon wafer using a vertical polishing device, the silicon wafer may tilt as desired or undesirably. For example, if the flatness of the silicon wafer needs to be adjusted, the flatness of the silicon wafer surface is adjusted by adjusting the deflection angle of the pair of polishing wheels. Specifically, referring to FIG. 1, FIG. 1 illustrates a structural schematic diagram of a vertical polishing device among the relevant technologies. Here, the vertical polishing device (30) includes a pair of polishing wheels (31) and a pair of fluid static pressure pads (32). The pair of fluid static pressure pads (32) support the silicon wafer (W) non-contactually through a fluid (L). To adjust the surface flatness of the silicon wafer, the pair of fluid static pressure pads (32) must be deflected in the same direction. In this case, the pair of polishing wheels (31) deflect the silicon wafer (W) at the same deflection angle. At this time, the silicon wafer (W) and the surface of the pair of static pressure pads (32) Contact may affect the quality of the silicon wafer (W) or cause fragmentation.

[0024] After processing is finished, the pair of grinding wheels (31) retract to an initial position away from the silicon wafer (W) along their own central axis, and the silicon wafer (W) is adsorbed to one of the pair of static pressure pads (32) by vacuum pressure. After waiting until the robot arm used for unloading adsorbs the silicon wafer (W) from the opposite side, the static pressure pad stops adsorbing and wafer acquisition is completed. However, during the processing process, a large amount of residue is sputtered onto the pair of static pressure pads (32), and since the pair of static pressure pads (32) do not have a self-cleaning function, a large amount of pit-shaped defects occur on the surface of the silicon wafer (W) when the silicon wafer (W) and the static pressure pad come into contact, and contaminants attached to the surface of the silicon wafer (W) can also cause the same problem.

[0025] To solve the technical problem described above, with reference to FIGS. 2 to 4, the present application provides a static pressure pad (10), wherein the static pressure pad (10) can determine the position of a target plane (C) where the silicon wafer (W) is located based on the spatial orientation of the silicon wafer (W), and the static pressure pad (10) adjusts the orientation of the static pressure pad (10) based on the target plane (C) so that the static pressure pad (10) is parallel to the target plane (C), thereby avoiding the silicon wafer (W) tilting and coming into contact with the static pressure pad (10), which would affect the quality of the silicon wafer (W) or cause fragmentation, and at the same time, the static pressure pad (10) reduces the contact area for supporting the silicon wafer (W) during the silicon wafer (W) unloading process, thereby reducing damage to the back surface of the silicon wafer (W).

[0026] Specifically, referring to FIGS. 2 and FIGS. 3, the static pressure pad (10) comprises a base (11), a plurality of static pressure blocks (12), and a driving module (not shown), wherein the base (11) has a fixed plane (A) facing the silicon wafer (W), the plurality of static pressure blocks (12) are uniformly distributed along the vertical direction on the fixed plane (A), and the plurality of static pressure blocks (12) can be moved in a direction perpendicular to the fixed plane (A) through the driving module so that a first plane (B) formed by the end of each of the plurality of static pressure blocks (12) is parallel to a target plane (C) where the silicon wafer (W) is located, wherein the number of the plurality of static pressure blocks (12) is at least two. The above-described static pressure pad (10) changes the spatial orientation of the first plane (B) by changing the height at which the plurality of static pressure blocks (12) protrude from the fixed plane (A), and changes the spatial orientation of the first plane (B) in a timely manner through the structure described above when the silicon wafer (W) is tilted so that the first plane (B) becomes parallel to the target plane (C).

[0027] Optionally, the static pressure pad (10) further includes a support block (not shown) for supporting the silicon wafer (W), and the support block can protrude from a fixed plane (A) of the base (11) under the drive of the drive module, and when the silicon wafer (W) is unloaded by a robot arm, the silicon wafer (W) moves until it comes into contact with the static pressure pad (10), and the support block protrudes from the fixed plane (A), and the protrusion height of the support block relative to the fixed plane (A) is greater than the protrusion height of the plurality of static pressure blocks (12), so that the support block comes into contact with the silicon wafer (W) before each of the plurality of static pressure blocks (12) and provides support to the silicon wafer (W), thereby reducing the surface area of ​​the static pressure pad (10) for supporting the silicon wafer (W) and thus avoiding damage to the back surface of the silicon wafer (W).

[0028] In order to avoid affecting the quality of the silicon wafer (W) or causing fragments to be generated when the silicon wafer (W) is tilted during the polishing process due to the movement of the related parts for polishing the silicon wafer (W), the pressure pad (10) provided in the embodiment of the present application, unlike a general fluid pressure pad, changes the configuration of the related parts on one side of the pressure pad (10) facing the silicon wafer (W) so that the surface of the pressure pad (10) facing the silicon wafer (W) always remains parallel to the silicon wafer (W), and at the same time, to avoid the surface of the silicon wafer (W) being scratched and damaged during the process of unloading the silicon wafer (W), the pressure pad (10) also reduces the area of ​​the related parts for supporting the silicon wafer (W).

[0029] Specifically, in order to stably support each component of the static pressure pad (10) so that the static pressure pad (10) stably supports the silicon wafer (W), the base (11) is generally made of metal, and with reference to FIGS. 2 and 3, the base (11) has a fixed plane (A) and a central axis (not shown), the fixed plane (A) is a surface of the base (11) facing the silicon wafer (W), the fixed plane (A) is located in a vertical plane, the central axis is perpendicular to the fixed plane (A), the plurality of static pressure blocks (12) are uniformly distributed in the vertical direction on the fixed plane (A) and protrude from the fixed plane (A), with reference to FIGS. 2 to 4, the plurality of static pressure blocks (12) are configured with equal lengths in the vertical direction, and with reference to FIG. 4, the plurality of static pressure blocks (12) are joined to match the shape of the base (11) on the fixed plane (A).

[0030] Before the silicon wafer (W) is tilted, the plurality of static pressure blocks (12) provide static pressure to the silicon wafer (W) in a manner that protrudes at the same height from the fixed plane (A) to support the silicon wafer (W), and the first plane (B) is parallel to the target plane (C). Referring to FIG. 2, the first plane (B) is located within a vertical plane, where the plurality of static pressure blocks (12) support one side of the silicon wafer (W) non-contactually through a fluid. When the silicon wafer (W) is tilted, the spatial orientation of the silicon wafer (W) changes, and a change occurs in the position of the target plane (C) where the silicon wafer (W) is located. For example, referring to FIG. 3, the silicon wafer (W) is tilted clockwise, and when a standard fluid static pressure pad is used, the silicon wafer (W) is tilted and comes into contact with the static pressure pad, which causes the polishing quality of the silicon wafer (W) to deteriorate or causes fragmentation. However, in an embodiment of the present application, when the silicon wafer (W) is tilted clockwise, the first plane (B) and the target plane (C) are no longer parallel, and the plurality of static pressure blocks (12) are extended along the central axis of the base (11) under the drive of the drive module so that the first plane (B) becomes parallel to the target plane (C), thereby avoiding contact between the silicon wafer (W) and the static pressure blocks, which would otherwise affect the quality of the silicon wafer (W) or cause fragmentation.

[0031] Specifically, when the first plane (B) and the target plane (C) are no longer parallel, the plurality of static pressure blocks (12) are protruded by different distances from the fixed plane (A) along the central axis direction under the drive of the drive module, thereby changing the spatial position of the first plane (B) formed by the ends of each static pressure block among the plurality of static pressure blocks (12) by moving to different positions along the central axis. For example, referring to FIGS. 2 and 3, the plurality of static pressure blocks (12) include a total of five static pressure blocks from top to bottom in the vertical direction, and before the silicon wafer (W) is tilted, the five static pressure blocks are installed on the fixed plane (A) in such a way that they protrude at the same height from the fixed plane (A), and the first plane (B) formed by the ends of the five static pressure blocks is located within the vertical plane and supports one side of the silicon wafer (W) with static pressure by spraying fluid toward one side of the silicon wafer (W). When the silicon wafer (W) is tilted as shown in FIG. 3, the five static pressure blocks extend toward the silicon wafer (W) along the central axis in such a way that the extension distance increases uniformly from top to bottom sequentially, causing the first plane (B) formed by the ends of the five static pressure blocks to also tilt clockwise. It should be noted that the five static pressure blocks are not limited to extending toward the silicon wafer (W) along the central axis under the driving of the driving module, and any of the five static pressure blocks may contract away from the silicon wafer (W) along the direction of the central axis, thereby achieving the effect of changing the spatial position of the first plane (B).

[0032] It should be noted that in a double-sided polishing device, a hydrostatic pad (10) is installed on both different sides of a silicon wafer (W) to provide fluid hydrostatic pressure and support the silicon wafer (W). As will be easily understood by those skilled in the art, when it is required that the hydrostatic pads (10) on both sides of the silicon wafer (W) be tilted, the tilt direction and tilt angle of each first plane (B) of the two hydrostatic pads (10) are consistent, but the extension and contraction states of the hydrostatic blocks used to implement the above-mentioned tilt are different. For example, referring to FIG. 3, the first plane (B) formed by a plurality of hydrostatic blocks (12) installed on the right side of the silicon wafer (W) is tilted clockwise, and the first plane (B) formed by a plurality of hydrostatic blocks (12) installed on the left side of the silicon wafer (W) is likewise tilted clockwise, but the extension and contraction states of the plurality of hydrostatic blocks (12) for implementing the tilt of each of the two first planes (B) are different.

[0033] The above drive module includes a drive unit for driving the movement of each static pressure block, and the drive unit may be selected as a hydraulic drive unit, a pneumatic drive unit, or other drive unit capable of implementing the movement of the static pressure block, and, for example, the drive unit uses a screw device driven by a motor, the screw device is installed within the base (11), and one end of the screw of the screw device is connected to one end of the static pressure block (12) located away from the silicon wafer (W), and the screw device is capable of extending and retracting in the direction of the central axis under the drive of the motor, thereby causing the static pressure block to move in the direction of the central axis.

[0034] In order to accurately obtain the specific spatial location of the target plane (C) which serves as the standard for the extension and contraction of the above static pressure block, the static pressure pad (10) further includes a sensor (not shown) and a controller (not shown). The sensor is used to detect the spatial orientation of the silicon wafer (W) to obtain specific location information of the target plane (C), and the controller is used to transmit a control signal to the driving module according to the location information of the target plane (C). Each driving unit in the driving module extends and contracts the corresponding static pressure block to realize the inclination of the first plane (B), thereby making the first plane (B) and the target plane (C) parallel.

[0035] Specifically, the sensor is a pressure sensor, and the pressure sensor is used to detect the static pressure received by the silicon wafer (W), and the static pressure is stably provided by the plurality of static pressure blocks (12), that is, the fluid discharged by the plurality of static pressure blocks (12) applies static pressure to one side of the silicon wafer (W) as a supporting force supporting the silicon wafer (W). When the first plane (B) and the target plane (C) are parallel, the static pressure received by each point of the silicon wafer (W) is identical in magnitude and direction; When the silicon wafer (W) is tilted, the pressure sensor detects a change in static pressure received by the silicon wafer (W), and the pressure sensor determines that the silicon wafer (W) is tilted by detecting a static pressure distribution of different sizes, and also recognizes a change in the silicon wafer (W) relative to its previous position based on the static pressure distribution of different sizes received by the silicon wafer (W), and thus obtains the spatial position of a new target plane (C) after the silicon wafer (W) is tilted, and the controller transmits a control signal to the driving module based on the new target plane (C), and the driving module controls the extension and contraction of each driving unit according to the control signal so that each corresponding static pressure block extends and contracts along the central axis direction, thereby tilting until the first plane (B) is parallel to the target plane (C).

[0036] In another embodiment of the present application, the sensor is a distance sensor, and the distance sensor is used to directly measure the distance between each point on the silicon wafer (W) and the fixed plane (A) of the base (11), wherein the distance refers to the straight-line distance between each point on the silicon wafer (W) and the fixed plane (A), and the straight line is a horizontal straight line. When the distance between each point on the silicon wafer (W) and the fixed plane (A) does not match, it is determined that the silicon wafer (W) is tilted, and the distance sensor obtains a narrow angle between the target plane (C) and the fixed plane (A) according to the distance between each point on the silicon wafer (W) and the fixed plane (A), and the controller transmits a control signal to the driving module based on the narrow angle, and the driving module controls the extension and contraction of each driving unit based on the control signal so that each corresponding static pressure block extends and contracts in the direction of the central axis, thereby tilting until the first plane (B) is parallel to the target plane (C).

[0037] Optionally, referring to FIG. 4, a plurality of via holes (T) are uniformly installed in each static pressure block, and the via holes (T) allow fluid to pass through the cross-section of the static pressure block under the action of pressure and be injected toward one side of the silicon wafer (W) toward the static pressure block, thereby enabling the silicon wafer (W) to be supported by fluid static pressure. It should be noted that fluid static pressure is provided to both different sides of the silicon wafer (W) in a double-sided polishing device, and as shown in FIG. 3, the static pressure pad (10) and another static pressure pad (20) according to an embodiment of the present application are each installed on different sides of the silicon wafer (W) to jointly provide fluid static pressure to the silicon wafer (W).

[0038] Optionally, the static pressure block includes a fluid pressure drive unit, and the fluid pressure drive unit is configured as follows: when the static pressure block applies static pressure to the surface of the silicon wafer (W) located on the target plane (C), the fluid pressure drive unit controls the pressure of the fluid in each static pressure block so that each static pressure block always applies a constant static pressure of the same magnitude to the surface of the silicon wafer (W) located on the target plane (C). Specifically, the fluid pressure drive unit includes a pressure cylinder for receiving fluid, a pressurizing unit, and a sensor, wherein the pressurizing unit is used to spray fluid at a constant pressure from the via hole (T), and the sensor is configured to detect the reaction force of the silicon wafer (W) against the fluid, and furthermore, the pressurizing unit controls the pressure when the fluid is sprayed from the via hole (T) based on the detection result of the sensor so that each static pressure block always applies a constant static pressure to the surface of the silicon wafer (W) located on the target plane (C).

[0039] After the silicon wafer (W) completes the polishing process through the aforementioned static pressure pad (10), the silicon wafer (W) is unloaded by a clamping method by a robot arm, and the robot arm drives the silicon wafer (W) to approach the static pressure pad (10) and also fixes the silicon wafer (W) by bringing it into contact with the static pressure pad (10) using a vacuum suction method. In order to avoid physical damage defects caused by friction of foreign substances or scratches occurring when the silicon wafer (W) comes into contact with the surface of one side of the static pressure pad (10), the static pressure pad (10) further includes a support block, the support block is used to protrude from the fixed plane (A) and come into contact with the silicon wafer (W) when the silicon wafer (W) comes into contact with the static pressure pad (10), the support block is installed on one side of the base (11) close to the silicon wafer (W), i.e., on the fixed plane (A), and the support block can extend and contract along the central axis direction under the drive of the drive module. When the plurality of static pressure blocks (12) fix the silicon wafer (W), the support block is retracted into the base (11) to avoid affecting the stability of the fluid used by the plurality of static pressure blocks (12) to fix the position of the silicon wafer (W), and at the same time, the attachment of residue and / or debris to the cross-section of the support block is reduced; when the silicon wafer (W) requires unloading, the support block extends outward from the fixing plane (A) of the base (11) and comes into contact with the silicon wafer (W).To ensure that the support block contacts the silicon wafer (W) before the plurality of static pressure blocks (12), the support block is configured as follows: with respect to the fixed plane (A), the height at which the support block protrudes from the fixed plane (A) is greater than the height at which any one of the plurality of static pressure blocks (12) protrudes from the fixed plane (A).

[0040] Optionally, to further increase the contact safety between the support block and the silicon wafer (W), a vacuum device is connected to one end of the support block located far from the silicon wafer (W), and a plurality of adsorption holes are installed at one end of the support block located close to the silicon wafer (W), and the support block adsorbs the silicon wafer (W) through the adsorption holes using a vacuum adsorption method.

[0041] Optionally, one end of the support block close to the silicon wafer (W) may be made of rubber or other soft material or wrapped with the aforementioned material to further prevent the surface of the silicon wafer (W) from being scratched.

[0042] An embodiment of the present application discloses a static pressure pad (10), wherein the static pressure pad (10) comprises a base (11), a plurality of static pressure blocks (12), and a driving module, wherein a via hole (T) is installed at the end of each static pressure block among the static pressure blocks (12) close to the silicon wafer (W), and the via hole (T) is used to support the silicon wafer (W) in a non-contact manner through which fluid flows out, and the driving module comprises a driving unit for driving the movement of each static pressure block, and each static pressure block may move closer to or further away from the silicon wafer (W) under the driving of the driving unit, and the static pressure pad (10) further comprises a sensor and a controller, and is characterized in that when the silicon wafer (W) is tilted due to a desired or unwanted cause, the target plane (C) where the silicon wafer (W) is located in space changes, the sensor is used to detect a change occurring in the silicon wafer (W) and to obtain a new spatial position of the target plane (C), and the controller is the A control signal is transmitted to the driving module based on the new spatial position of the target plane (C), and the driving module drives the plurality of static pressure blocks (12) to move in a horizontal direction based on the control signal until the first plane (B) formed by the end of each static pressure block and the target plane (C) located after the silicon wafer (W) is tilted become parallel.

[0043] Through the above-described static pressure pad (10), the distance between the static pressure pad (10) and the silicon wafer (W) can be adjusted in real time, and by maintaining the static pressure pad (10) and the silicon wafer (W) in parallel at all times, the stability of the polishing process is ensured and the product quality is improved. It should be noted that when using the above-described static pressure pad (10), the static pressure pad (10) is installed on both different sides of the silicon wafer (W) to provide fluid static pressure and support the silicon wafer (W), and the adjustment principle of the static pressure pads (10) located on both sides of the silicon wafer (W) is the same, and the technical effect ultimately achieved is to ensure that the static pressure pad (10) and the silicon wafer (W) are parallel.

[0044] Based on the silicon wafer (W) described above, embodiments of the present application further provide a polishing device, said polishing device for polishing both sides of the silicon wafer (W), said polishing device comprises a carrier, a pair of polishing wheels, and a pair of the aforementioned static pressure pads (10). The carrier is for fixing the silicon wafer (W) along a vertical direction; said pair of polishing wheels are symmetrically installed on both sides of the silicon wafer (W) relative to the carrier; and said pair of the aforementioned static pressure pads (10) are symmetrically installed on both sides of the silicon wafer (W) relative to the carrier. Specifically, referring to FIG. 4, the external shape of the static pressure pad (10) is configured in a crescent shape, which is to install a grinding wheel in a circular notch in a double-sided polishing device for a silicon wafer (W). The pair of polishing wheels rotate around a common rotation axis to polish two main surfaces of the silicon wafer (W) that are fixed by the carrier and supported by the pair of static pressure pads (10), and the polishing wheels can retract into the circular notch of the polishing pad when not polishing the silicon wafer (W).

[0045] Based on the polishing device described above, an embodiment of the present application further provides a silicon wafer (W), said silicon wafer (W) is obtained using the polishing device described above.

[0046] It should be explained that the technical solutions described in the embodiments of this application may be combined arbitrarily where there is no conflict.

[0047] The foregoing describes merely specific embodiments of the present application and is not limited thereto. Any modifications or substitutions that a person skilled in the art could readily conceive within the scope of the technology disclosed in this application should be included within the scope of protection of the present application. Accordingly, the scope of protection of the present application is based on the scope of protection of the above claims.

Claims

Claim 1 A static pressure pad, wherein the static pressure pad is used to clamp both sides of a silicon wafer in pairs in a silicon wafer double-sided polishing machine, and the static pressure pad comprises: a base having a fixed plane facing the silicon wafer; a plurality of static pressure blocks uniformly distributed along a direction perpendicular to the fixed plane and protruding from the fixed plane, providing static pressure to the silicon wafer through a fluid to support one side of the silicon wafer non-contactually; and a driving module configured to drive each static pressure block to move along a direction perpendicular to the fixed plane when the first plane formed by the cross-section of each static pressure block facing the silicon wafer is not parallel to the target plane where the silicon wafer is located, so that the first plane becomes parallel to the target plane. Claim 2 In claim 1, the static pressure pad further comprises a support block installed on the fixed plane, wherein the support block can move along a direction perpendicular to the fixed plane and protrude from the fixed plane, and the support block is configured such that the protrusion height of the support block relative to the fixed plane is greater than the protrusion height of any one of the plurality of static pressure blocks; and a plurality of adsorption holes are installed at one end of the support block close to the silicon wafer, and the adsorption holes are configured to adsorb the silicon wafer through a vacuum. Claim 3 In claim 1, the static pressure pad further comprises a sensor and a controller, wherein the sensor is used to detect the spatial position of the target plane, the controller transmits a control signal to the driving module based on the spatial position of the target plane, and the driving module drives the movement of the plurality of static pressure blocks according to the control signal so that the first plane is parallel to the target plane; the sensor is a pressure sensor, and the pressure sensor is used to detect a change in the silicon wafer receiving the static pressure to obtain the spatial orientation of the silicon wafer; or, the sensor is a distance sensor, and the distance sensor is used to detect the distance between the silicon wafer and the first plane to obtain the spatial orientation of the silicon wafer. Claim 4 A static pressure pad according to claim 1, wherein a plurality of via holes are installed at one end of each static pressure block close to the silicon wafer, and the via holes are configured to support the silicon wafer in a non-contact manner through which the fluid flows out. Claim 5 In claim 1, the drive module comprises a static pressure pad including a hydraulic drive unit or a pneumatic drive unit for driving the movement of the static pressure block. Claim 6 A polishing device, wherein the polishing device is for polishing both sides of a silicon wafer, and the polishing device comprises: a carrier for supporting the silicon wafer along a vertical direction; two polishing wheels symmetrically installed with respect to the carrier; and two hydrostatic pads according to any one of claims 1 to 5 symmetrically installed with respect to the carrier. Claim 7 In the case of a silicon wafer, the silicon wafer is a silicon wafer obtained using a polishing device according to claim 6. Claim 8 delete Claim 9 delete Claim 10 delete

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