Wafer grinding device and slurry flow control system

Abstract

The utility model provides a wafer grinding device which comprises a polishing plate, a slurry circulating plate and a slurry circulating device, the polishing plate comprises a polishing face, a back face opposite to the polishing face and a plurality of slurry supply holes, the polishing face is used for polishing wafers, and the slurry supply holes penetrate from the polishing face to the back face opposite to the polishing face; the slurry circulating plate comprises a path for circulating the slurry, a plurality of slurry supply ports communicated with the plurality of slurry supply holes in a one-to-one correspondence manner on the path, a slurry injection port for injecting the slurry into the path and a slurry discharge port for discharging the slurry from the path; the slurry circulating device is used for injecting slurry into the slurry injection port and receiving the slurry discharged from the slurry discharge port, so that the slurry is circulated on a path; the plurality of slurry supply ports supply slurry to the polishing surface through the plurality of slurry supply holes. The slurry circulation device is used for controlling the slurry to circulate in the slurry circulation path, and meanwhile, the slurry is supplied to the grinding surface of the polishing plate from the plurality of slurry supply holes, so that the slurry can be uniformly supplied to the whole grinding surface, and the grinding rate of the surface of a wafer and the uniformity of the grinding amount are improved.

Description

Technical Field

[0001] The present application relates to a polishing device and a slurry flow control system for CMP processing, and in particular to a wafer polishing device using a semiconductor wafer or the like as a polishing object and a slurry flow control system using the wafer polishing device. Background Art

[0002] When forming device structures such as transistors or wiring structures on the surface of various semiconductor wafers such as silicon (Si), silicon carbide (SiC), and gallium nitride (GaN), it is necessary to use an exposure device to transfer the pattern of the area that determines the device structure or wiring structure onto the wafer.

[0003] At this time, if the wafer surface is not flat, the pattern cannot be transferred correctly, which eventually leads to abnormalities in the formed device structure or wiring structure. Therefore, a CMP (chemical mechanical polishing) device is needed to flatten the wafer surface.

[0004] Furthermore, in the manufacturing process of semiconductor devices, it is sometimes necessary to stack structures such as transistor elements and wiring on the surface of a wafer, and a polishing process based on CMP processing is also required in the process of forming this stacked structure.

[0005] When using a CMP device for CMP processing, it is necessary to impregnate the polishing pad with slurry, press the polishing head holding the wafer onto the polishing plate, and make the polishing head and the polishing plate slide against each other while rotating. The slurry used in the CMP process contains abrasives or abrasive particles formulated according to the composition or structure of the polishing object and the purpose of polishing. The surface of the wafer is flattened by mechanical polishing combined with the chemical reaction of the abrasive and abrasive particles with the wafer surface.

[0006] Normally, during the grinding process of a CMP device, a slurry is sprayed onto the grinding pad surface of the polishing plate through a nozzle arranged near the grinding head. However, this method cannot spread the slurry over the entire wafer surface (especially the central part of the wafer), so the deviation of the grinding rate, grinding amount, and temperature of the wafer surface will become larger.

[0007] In order to solve this problem, Patent Document 1 (JPH11285962) discloses a polishing device that supplies slurry from the bottom of a polishing plate that carries a polishing pad to the top of the polishing pad via a polishing slurry supply pipe (a main supply pipe and a sub-supply pipe) inside the polishing plate and a through hole inside the polishing pad. In this way, slurry can also be supplied to the center of the wafer, and the slurry can be spread over the entire surface of the wafer.

[0008] In addition, in the grinding device of patent document 1, a valve is provided inside the through hole for supplying slurry to the grinding pad, and the valve is opened only when the polishing surface including the through hole is pressed by the wafer. Thus, a sufficient amount of slurry can be supplied only to the part of the polishing surface of the grinding pad that contacts the wafer.

[0009] In the polishing device of Patent Document 1, the slurry is supplied from the lower part of the polishing plate (platform) to the polishing slurry main supply pipe inside the polishing plate (platform), and then distributed to a plurality of polishing slurry auxiliary supply pipes, and supplied to the upper surface of the polishing pad through the through-hole inside the polishing pad. That is, after the slurry is distributed to the plurality of polishing slurry auxiliary supply pipes, it is not merged again, and is directly supplied to the polishing surface of the polishing pad through the through-hole provided in the polishing pad.

[0010] Therefore, in the polishing device of Patent Document 1, after the slurry is distributed to multiple polishing slurry sub-supply pipes, the characteristics of the slurry inside each polishing slurry sub-supply pipe may change, and then these uneven slurries with different characteristics are supplied to the polishing surface from different through holes.

[0011] In particular, in Patent Document 1, when there is no wafer on a certain area of ​​the polishing pad, the valve corresponding to the through hole for supplying slurry to the area remains closed, and the above-mentioned problem occurs.

[0012] In such a polishing device, the opening and closing frequency of the valve corresponding to the through hole provided on the polishing pad changes according to the change in the contact frequency between the wafer and the polishing surface area including the through hole. Therefore, in the through hole where the valve opening frequency is low and the through hole where the valve opening frequency is high, the slurry is retained, and there is a possibility that the slurry solidifies and the slurry temperature rises, compared with the through hole where the slurry is continuously supplied to the polishing surface of the polishing pad.

[0013] Therefore, the slurry supplied to different through holes lacks uniformity in terms of concentration and temperature, which may eventually cause deviations in the polishing rate and polishing amount on the wafer surface. Utility Model Content

[0014] The present application aims to address the problem that when the existing wafer grinding apparatus supplies slurry through different through holes from under the grinding plate, the concentration and temperature of the slurry at different positions lack uniformity, thereby causing deviations in the grinding rate and grinding amount produced on the wafer surface. The present application provides a wafer grinding apparatus that can improve the uniformity of the grinding rate and grinding amount produced on the wafer surface.

[0015] The technical solution of this application is as follows:

[0016] In a first aspect, the present application provides a wafer grinding device, which comprises: a polishing plate, a slurry circulation plate, and a slurry circulation device, wherein:

[0017] The polishing plate comprises a polishing surface, a back surface opposite to the polishing surface, and a plurality of slurry supply holes, wherein the polishing surface is used for polishing the wafer, and the plurality of slurry supply holes penetrate from the polishing surface to the back surface opposite to the polishing surface;

[0018] The slurry circulation plate includes a path for circulating the slurry, a plurality of slurry supply ports on the path that are connected to the plurality of slurry supply holes in a one-to-one correspondence, a slurry injection port for injecting slurry into the path, and a slurry discharge port for discharging slurry from the path;

[0019] The slurry circulation device is used to inject slurry into the slurry injection port and receive the slurry discharged from the slurry discharge port, thereby circulating the slurry on the path;

[0020] The plurality of slurry supply ports supply slurry to the polishing surface through the plurality of slurry supply holes.

[0021] The slurry is injected into the slurry injection port through the slurry circulation device, and the slurry discharged from the slurry discharge port is received, thereby making the slurry circulate on the path within the slurry circulation plate. At the same time, by supplying slurry to the grinding surface of the polishing plate from multiple slurry supply holes, the slurry can be evenly supplied to the entire grinding surface, thereby improving the grinding rate and the uniformity of the grinding amount of the chip surface.

[0022] Optionally, the path is composed of a plurality of separate sub-paths, and each of the plurality of separate sub-paths is provided with a corresponding slurry supply port, a slurry injection port and a slurry discharge port.

[0023] By setting a plurality of separate sub-paths, the effect of individually controlling a plurality of areas of the slurry circulation plate can be achieved.

[0024] Optionally, the plurality of separated sub-paths include at least a first path and a second path, the first path is formed in a central portion of the slurry circulation plate, and the second path is formed in a peripheral portion of the slurry circulation plate.

[0025] By providing the first path and the second path, the central portion and the peripheral portion of the slurry circulation plate can be controlled and adjusted individually.

[0026] Optionally, multiple separated sub-paths are each connected to a slurry circulation device that is independently arranged. Different slurry circulation devices inject slurry into the corresponding sub-paths from their respective connected slurry injection ports, and receive the discharged slurry from their respective connected slurry discharge ports, thereby allowing the slurry to circulate on the corresponding sub-paths.

[0027] By independently setting up different slurry circulation devices to connect with the sub-paths, the slurry in each sub-path can be independently controlled and adjusted.

[0028] Optionally, the slurry injection port and the slurry discharge port are both located on the lower surface of the slurry circulation plate, the slurry supply port is located on the upper surface of the slurry circulation plate, and the slurry injection port, the slurry discharge port and the slurry supply port are all connected through a path.

[0029] The slurry feeding and circulating transportation are realized by arranging the slurry injection port, the slurry discharge port and the slurry supply port which are interconnected.

[0030] Optionally, the path includes a plurality of first channels and second channels, the first channels are arranged in an annular or arc shape inside the slurry circulation plate, and the second channels extend radially along the slurry circulation plate and are used to connect adjacent first channels.

[0031] By providing a plurality of first channels and a plurality of second channels, it is possible to more easily achieve uniform circulation of the slurry in the slurry circulation plate.

[0032] Optionally, the slurry injection port and the slurry discharge port are equidistantly distributed on the path; the slurry supply holes are equidistantly distributed in a circular shape on a plurality of concentric circles with the center of the polishing plate as the center.

[0033] By equidistantly arranging the slurry injection port, slurry discharge port and slurry supply hole, the slurry supplied to the polishing surface is made more uniform, thereby improving the uniformity of the grinding rate and grinding amount of the wafer surface.

[0034] Optionally, the slurry circulation device is also used to control at least one parameter of the type, concentration, temperature and flow rate of the slurry flowing into the slurry circulation plate.

[0035] At least one parameter of the slurry flowing into the slurry circulation plate is controlled by the slurry circulation device to improve the compatibility and grinding effect of the equipment.

[0036] Optionally, the multiple slurry supply holes are further configured with a cover plate with a variable opening size to adjust the flow rate of the slurry flowing out of the multiple slurry supply holes.

[0037] The flow rate of the slurry flowing out of the slurry supply hole is adjusted by the cover plate, so as to adjust the temperature and amount of the slurry on the polishing plate.

[0038] In a second aspect, the present application further provides a slurry flow control system, which includes a flow monitor, a control unit and the above-mentioned wafer polishing device, wherein:

[0039] The flow monitor is used to monitor the flow of slurry on the polishing surface in real time;

[0040] The control unit controls the wafer grinding device according to the output information of the flow monitor to make the flow deviation of the slurry on the polishing surface uniform.

[0041] The flow monitor monitors the slurry flow on the polishing surface in real time. The control unit cooperates with the wafer grinding device to implement parameters such as the flow rate, concentration and temperature of the slurry during the wafer grinding process, further improving the grinding rate and uniformity of the wafer surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic diagram of a grinding device in a first embodiment of the present application;

[0043] Figure 2 A top view of a polishing plate in the first embodiment of the present application;

[0044] Figure 3 A top view of a slurry circulation plate in the first embodiment of the present application;

[0045] Figure 4 A cross-sectional view of a polishing plate in the first embodiment of the present application;

[0046] Figure 5 A top view of a slurry circulation plate in a second embodiment of the present application;

[0047] Figure 6 A cross-sectional view of a polishing plate in a second embodiment of the present application;

[0048] Figure 7 This is a schematic diagram of a slurry flow control system in the third embodiment of the present application.

[0049] Figure 1 to Figure 7 Including:

[0050] 1. Grinding device; 2. Grinding head unit; 3. Polishing plate unit; 10. Grinding head; 11. Wafer holding part; 12. Holding ring; 13. Grinding head rotating spindle; 14. Polishing plate; 15. Slurry circulation plate; 16. Polishing plate rotating spindle; 200. Slurry supply hole; 201, 202, 203, 204, 205, 206 circles; 300. Slurry supply port; 301, path; 302. Slurry injection port; 303. Slurry discharge port; 310, support surface; 31, first part; 32, second part; 33, first dot-dash line; 34, second dot-dash line; 304, first path; 305, second path; 4, slurry flow control system; 47, flow monitor; 46, control unit; 44, slurry circulation device; 43, first motor; 40, second motor; 42, first drive shaft; 41, second drive shaft; 45, cooling medium circulation passage; 48, slurry flow regulating device. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0052] The first embodiment of the present application is described below:

[0053] Figure 1 Schematic diagram of a polishing device in a first embodiment of the present application. The polishing device 1 is used for CMP (chemical mechanical polishing) of a disc-shaped polishing object such as a semiconductor wafer. The polishing device 1 is composed of a polishing head unit 2 and a polishing plate unit 3.

[0054] The grinding head unit 2 is used to hold the semiconductor wafer (hereinafter referred to as the wafer) during the grinding process, and press the wafer on the platform formed by the grinding pad of the polishing plate unit 3, and drive the wafer to rotate or even swing. The polishing plate unit 3 is configured to polish the wafer using the platform formed by the polishing pad on the polishing plate by rotating the polishing plate.

[0055] First, the specific structure of the polishing head unit 2 will be described below. The polishing head unit 2 includes a polishing head 10 , a wafer holding portion 11 , and a holding ring 12 .

[0056] The main part of the grinding head unit 2 is a grinding head 10. A grinding head rotating spindle 13 for driving the grinding head 10 to rotate is provided at the upper end of the grinding head 10. A driving shaft for driving the grinding head 10 to rotate is installed inside the grinding head rotating spindle 13, and the driving shaft is driven by a motor.

[0057] A wafer holding portion 11 for holding a wafer is provided at the lower end of the polishing head unit 2. In order to hold the wafer, a ceramic plate, a sealing gasket, a film, etc. may be mounted on the wafer holding portion 11 as a tool for holding the wafer.

[0058] When the wafer holding part 11 holds the wafer by means of a ceramic plate, an adhesive such as wax needs to be applied to the opposite side of the wafer grinding surface so that the wafer is adhered and held on the ceramic plate. When the wafer holding part 11 holds the wafer by means of a sealing pad, wax is not required, but the wafer is held on the sealing pad by adsorption.

[0059] The wafer holding part 11 further includes a flexible member, such as a film, disposed on the upper end of the ceramic plate or the sealing pad. The pressure applied by the chamber inside the polishing head 10 is absorbed and adjusted by the flexible member.

[0060] An annular holding ring 12 is provided at a peripheral position of the wafer below the wafer holding portion 11. The holding ring 12 is provided around the wafer to be polished to hold the wafer.

[0061] The polishing plate unit 3 is described in detail below. The polishing plate unit 3 includes a polishing plate 14, a slurry circulation plate 15 for circulating the slurry supplied to the polishing plate 14, and a polishing plate rotation spindle 16. In addition, the polishing plate unit in this embodiment is generally also called a platen (pressing plate).

[0062] The polishing plate 14 is a disk-shaped component for polishing the wafer pressed by the grinding head 10. A polishing pad is installed on the upper end of the polishing plate 14, that is, on the polishing surface for polishing the wafer. The polishing pad can be made of hard materials such as polyurethane or soft materials such as non-woven fabrics and suede.

[0063] The polishing plate 14 has slurry supply holes extending from the upper surface (polishing surface) to the lower surface (back surface opposite to the polishing surface) of the polishing plate 14. The polishing plate 14 is made of a hard material such as metal except for the polishing pad.

[0064] A slurry circulation plate 15 for supplying slurry to the polishing plate 14 and circulating the slurry is provided on the back side of the polishing plate 14 , that is, on the side opposite to the polishing surface.

[0065] The slurry circulation plate 15 has a support surface for supporting the back side of the polishing plate 14. Inside the slurry circulation plate 15, there is a path for circulating the slurry on the support surface side (i.e., the upper side). A slurry supply port for supplying slurry to the slurry supply hole of the polishing plate 14 is provided on the upper side of the path for circulating the slurry. In addition, a slurry injection port for injecting slurry into the path for circulating the slurry and a slurry discharge port for discharging slurry from the path for circulating the slurry are provided on the lower side of the path for circulating the slurry. The detailed structure will be described later.

[0066] In addition, a passage for circulating slurry is provided below the polishing plate unit 3 .

[0067] The polishing plate 14 and the slurry circulation plate 15 are supported by a polishing plate rotating shaft 16. A drive shaft for controlling the rotation of the polishing plate 14 and the slurry circulation plate 15 is arranged inside the polishing plate rotating shaft 16, and the drive shaft is driven by a motor. A passage (such as a rotary joint, etc.) for circulating the slurry between the slurry circulation plate 15 and the slurry circulation device arranged outside is also arranged inside the polishing plate rotating shaft 16.

[0068] Figure 2 This is a top view (grinding surface side) of the polishing plate 14 in the first embodiment of the present application. The polishing plate 14 is approximately disc-shaped. The polishing plate 14 is provided with a slurry supply hole 200 extending from the upper surface (polishing surface) of the polishing plate 14 to the lower surface (back surface) of the polishing plate 14. The number of the slurry supply holes 200 can be one or more.

[0069] The slurry supply hole 200 can be provided at any position of the polishing plate 14. For example, preferably, the slurry supply hole 200 is provided in a circumferential shape on a concentric circle with the center of the polishing plate 14 as the center. In addition, the slurry supply hole 200 can also be provided at the center of the polishing plate 14.

[0070] Optionally, the aperture of the slurry supply hole can be from 0.1 mm to several tens of millimeters. In addition, optionally, each slurry supply hole is respectively provided with a cover plate that can be opened and closed and the size of the opening is variable. The supply amount of the slurry is adjusted by adjusting the opening size of the cover plate. In one possible implementation, the cover plate of the slurry supply hole is combined with a correspondingly arranged pressure sensor. When the pressure sensor senses that there is no grinding object (i.e., no wafer) at the position corresponding to the slurry supply hole, the slurry supply hole is completely closed by closing the cover plate opening.

[0071] See also Figure 2 ,like Figure 2 As shown, optionally, on the same polishing plate 14, four slurry supply holes 200 are arranged on a concentric circle 201 with the center of the polishing plate 14 as the center, eight slurry supply holes are arranged on a circle 202, four slurry supply holes are arranged on a circle 203, four slurry supply holes are arranged on a circle 204, eight slurry supply holes are arranged on a circle 205, and eight slurry supply holes are arranged on a circle 206. In addition, Figure 2 The concentric circles 200 to 206 shown in FIG. 1 are for the convenience of explanation and are not actually depicted on the polishing plate 14 .

[0072] Figure 3 It is a top view of the slurry circulation plate 15 in the first embodiment of the present application. Figure 4 This is a cross-sectional view of the polishing plate unit 3 in the first embodiment of the present application ( Figure 3 X-X' section in the figure).

[0073] Optionally, the polishing plate 14 and the slurry circulation plate 15 are both in the shape of discs with the same diameter. The polishing plate 14 is installed above the slurry circulation plate 15, and the polishing plate 14 and the slurry circulation plate 15 have the same rotation axis, and the center of the polishing plate 14 is consistent with the center of the slurry circulation plate 15.

[0074] In a possible embodiment, a path 301 for supplying slurry is provided on the slurry circulation plate 15. The slurry circulation plate 15 has a support surface 310 for supporting the back of the polishing plate 14. The path 301 of the slurry circulation plate 15 is provided with a slurry supply port 300 for supplying slurry to the slurry supply hole 200 of the polishing plate 14, a slurry injection port 302 for injecting slurry into the path 301, and a slurry discharge port 303 for discharging the slurry in the path 301. In addition, a passage for circulating the slurry is provided below the slurry circulation plate 15, and the passage is connected to the slurry supply port 300 and the slurry discharge port 301, respectively.

[0075] Path 301 includes Figure 2 The circles 201, 202, 203, 204, 205, and 206 shown in the figure form a plurality of annular or arc-shaped first channels and a plurality of second channels extending radially for connecting the first channels. The path 301 is arranged on one side of the support surface 310 of the slurry circulation plate 15. Of course, the path 301 can also adopt other structures, which will not be described in detail here.

[0076] Moreover, path 301 is also provided with Figure 2 The slurry supply ports 300 corresponding to the slurry supply holes 200 opened on the circles 201, 202, 203, 204, 205, and 206 are correspondingly arranged directly below the slurry supply holes 200. A plurality of slurry supply ports 300 are arranged on one side of the path 301 close to the supporting surface 310, and each slurry supply port 300 is connected to the corresponding slurry supply hole 200. In the present application, slurry is supplied to the slurry supply hole 200 through the slurry supply port 300, so as to supply slurry to the grinding surface of the polishing plate 14.

[0077] In addition, a slurry injection port 302 for injecting slurry into the path 301 and a slurry discharge port 303 for discharging slurry from the path 301 are provided on the lower side of the path 301 .

[0078] In one possible implementation, Figure 3 and Figure 4 As shown, three slurry injection ports 302 and four slurry discharge ports 303 are provided on the path 301 of the slurry circulation plate 15. In addition, the slurry injection port 302 is provided at the central part of the slurry circulation plate 15, and the slurry discharge ports 303 are provided at the peripheral part of the slurry circulation plate 15.

[0079] When the slurry circulation plate 15 rotates, the slurry is exerted with a centrifugal force outward in the radial direction. At this time, the annular or arc-shaped first channel is equivalent to a stopper, which is used to prevent the slurry from moving rapidly outward in the radial direction. The slurry first moves circumferentially on the annular or arc-shaped first channel, and then moves along a plurality of second channels extending radially and connecting these first channels.

[0080] By setting the slurry injection port 302 at the central part of the slurry circulation plate 15 and setting the slurry discharge port 303 at the peripheral part of the slurry circulation plate 15, the slurry can be smoothly circulated. However, in other embodiments, the number of the slurry injection port 302 and the slurry discharge port 303 can also be set to any number. In addition, the positions of the slurry injection port 302 and the slurry discharge port 303 can also be set at any position of the path 301. Moreover, by setting a plurality of slurry injection ports 302 and slurry discharge ports 303 at equal intervals on the path 301, the slurry can be circulated at a more uniform flow rate.

[0081] A connected recovery channel is provided below the slurry circulation plate 15 of the polishing plate unit 3 and on the polishing plate rotating shaft 16, and the slurry is injected into the slurry circulation plate 15 from the slurry injection port 302 through the slurry circulation device provided outside. In addition, the slurry is discharged from the slurry discharge port 303, collected through the recovery channel and returned to the slurry circulation device. Thus, the slurry is circulated in the path 301 via the slurry circulation device.

[0082] Utilizing the above structure, slurry is injected into the slurry injection port 302 through the slurry circulation device, and then the slurry is discharged from the slurry discharge port 303 to the slurry circulation device. Thus, the slurry can circulate in the path 301 of the slurry circulation plate 15, and the effect of supplying slurry from the multiple slurry supply ports 300 through the multiple slurry supply holes 200 of the polishing plate 14 to the grinding surface of the polishing plate 14 is achieved.

[0083] Here, in the CMP process, by circulating the slurry in the path 301 in the slurry circulation plate 15 in the polishing plate unit 3 while supplying the slurry to the grinding surface of the polishing plate from a plurality of slurry supply holes, it is possible to supply the abrasive to the central portion of the wafer so that the abrasive spreads over the entire wafer surface, thereby improving the grinding rate and uniformity of the grinding amount on the wafer surface.

[0084] The second embodiment of the present application is described below: Since the first embodiment and the second embodiment are basically the same in structure except for the slurry circulation plate 15, only the slurry circulation plate 15 in the second embodiment of the present application is described below.

[0085] In the second embodiment of the present application, the structure of the slurry circulation plate 15 is as follows: Figure 5 and Figure 6shown. Figure 5 It is a top view of the slurry circulation plate 15 in the second embodiment of the present application. Figure 6 For use Figure 5 When the slurry circulation plate 15 is shown, the cross-sectional view of the polishing plate unit 3 ( Figure 5 X-X' section in the figure).

[0086] Figure 5 The slurry circulation plate 15 shown includes a first portion 31 corresponding to the central area of ​​the polishing plate 14 and a second portion 32 corresponding to the peripheral area of ​​the polishing plate 14. The first portion 31 can be configured to be a disc in accordance with the central area of ​​the polishing plate 14, and the second portion 32 can be configured to be a ring in accordance with the peripheral area of ​​the polishing plate 14.

[0087] The second embodiment is the same as the first embodiment, and the polishing plate 14 and the slurry circulation plate 15 are both in the shape of a disk with the same diameter. In addition, the polishing plate 14 is installed above the slurry circulation plate 15, and the rotation axes of the polishing plate 14 and the slurry circulation plate 15 are consistent, and the center of the polishing plate 14 is consistent with the center of the slurry circulation plate 15.

[0088] like Figure 5 As shown, the first portion 31 is located inside the area surrounded by the first dotted line 33, and the second portion 32 is located in the area between the first dotted line 33 and the second dotted line 34. The first portion 31 is provided with a first path 304 for supplying slurry to the central area of ​​the polishing plate 14. The second portion 32 is provided with a second path 305 for supplying slurry to the peripheral area of ​​the polishing plate 14. It should be noted that Figure 5 The first dot-dash line 33 and the second dot-dash line 34 are shown for convenience of explanation and are not actually depicted on the slurry circulation plate 15 .

[0089] In this embodiment, the first path 304 includes Figure 2 The positions of the circles 201 and 202 shown in the figure correspond to the formation of a plurality of first circular channels and a first straight channel extending in the radial direction for connecting the first circular channels. Figure 2 The positions of the circles 203, 204, 205, and 206 shown correspond to the multiple second circular channels and arc channels formed and the multiple second straight channels extending radially for connecting the second circular channels or arc channels. It should be noted that the first path 304 and the second path 305 are separated, and the slurry flowing through them does not merge on the slurry circulation plate 15.

[0090] Furthermore, specifically, the polishing plate 14 corresponds to Figure 2A plurality of slurry supply holes 200 are provided above the circles 201 and 202 shown. A plurality of slurry supply ports 300 for supplying slurry to the grinding surface of the polishing plate 14 are provided on the first path 304 . Each slurry supply port 300 is connected to a slurry supply hole 200 .

[0091] Similarly, polishing plate 14 corresponds to Figure 2 A plurality of slurry supply holes 200 are also provided above the circles 203, 204, 205 and 206 shown. A plurality of slurry supply ports 300 for supplying slurry to the grinding surface of the polishing plate 14 are provided on the second path 305. Each slurry supply port 300 is connected to a slurry supply hole 200, respectively.

[0092] The slurry supply port 300 supplies slurry to the slurry supply hole 200 , and the slurry supply hole 200 supplies slurry to the polishing surface of the polishing pad 14 .

[0093] like Figure 5 As shown, in an achievable implementation, a slurry injection port 302 and two slurry discharge ports 303 are provided on the first path 304 of the slurry circulation plate 15. Of course, the number of the slurry injection ports 302 and the slurry discharge ports 303 on the first path 304 can also be set to any number. In addition, the positions of the slurry injection ports 302 and the slurry discharge ports 303 are not limited and can be set at any position of the first path 304.

[0094] See also Figure 5 , two injection ports 302 and two slurry discharge ports 303 are provided on the second path 305 of the slurry circulation plate 15. Of course, the number of the slurry injection ports 302 and the slurry discharge ports 303 on the second path 305 can also be set to any number. The positions where the slurry injection ports 302 and the slurry discharge ports 303 are provided are also not limited, and they can be provided at any position of the second path 305. In addition, when a plurality of slurry injection ports 302 and slurry discharge ports 303 are provided respectively, by arranging the plurality of slurry injection ports 302 and slurry discharge ports 303 at equal intervals on the first path 304 and the second path 305, the slurry can be more easily circulated at a uniform flow rate.

[0095] The slurry circulation device provided outside supplies slurry to the slurry injection port 302 through a passage connecting the slurry circulation plate 15 provided below the polishing plate unit 3 and the polishing plate rotating spindle 16. In addition, the slurry discharged from the slurry discharge port 303 is returned to the slurry circulation device via the passage provided below the slurry circulation plate 15 of the polishing plate unit 3 and the polishing plate rotating spindle 16. Thus, the slurry is circulated in the first path 304 and the second path 305 via the slurry circulation device.

[0096] In a feasible implementation, slurry can be supplied to the slurry injection port 302 on the first path 304 and the slurry injection port 302 on the second path 305 respectively through independently arranged slurry circulation devices that are not connected to each other. In this case, the slurry discharge port 303 on the first path 304 and the slurry discharge port 303 on the second path 305 are each returned to the corresponding slurry circulation device. Then, through these corresponding slurry circulation devices, the slurry is independently circulated in the first path 304 and the second path 305.

[0097] Therefore, by individually controlling the temperature, flow rate, type, etc. of the slurry flowing through the first path 304 and the second path 305 , the slurry supplied to the central area and the peripheral area of ​​the polishing pad 14 can be freely adjusted.

[0098] In addition, when the slurry circulation plate 15 rotates, the slurry is exerted with a centrifugal force outward in the radial direction, and the annular or arc-shaped first channel becomes a stopper to prevent the slurry from rapidly moving outward in the radial direction. The slurry first moves circumferentially on the annular or arc-shaped first channel, and then moves along a plurality of second channels extending in the radial direction and connecting the first channels.

[0099] Therefore, by setting the slurry injection port 302 on the inner side of the first path 304 and the second path 305, and setting the slurry discharge port 303 on the outer side of the path 304 and the path 305, the slurry can be smoothly circulated. However, irrelevant to the above, the number of the slurry injection port 302 and the slurry discharge port 303 can also be set to any number. In addition, the position where the slurry injection port 302 and the slurry discharge port 303 are set can also be any corresponding position on the first path 304 and the second path 305. Moreover, when a plurality of slurry injection ports 302 and slurry discharge ports 303 are respectively set on the first path 304 and the second path 305, it will be easier to achieve uniform circulation of the slurry by arranging the plurality of slurry injection ports 302 and slurry discharge ports 303 on the first path 304 and the second path 305 at equal intervals.

[0100] By adopting the above structure, the slurry circulation device for circulating the slurry injects slurry into the slurry injection port 302, and then discharges the slurry from the slurry discharge port 303 to the slurry circulation device, so that the slurry can circulate in the first path 303 and the second path 304 of the slurry circulation plate 15, and can supply the slurry to the grinding surface of the polishing plate 14 through the multiple slurry supply ports 300 and the corresponding multiple slurry supply holes 200 on the polishing plate 14.

[0101] In summary, while the slurry circulates in the first path 303 and the second path 304 in the slurry circulation plate 15 of the polishing plate unit 3, the slurry is supplied to the polishing surface of the polishing plate from the plurality of slurry supply holes, thereby, in the CMP process, the abrasive can also be supplied to the central part of the wafer so that the abrasive spreads over the entire wafer surface, thereby improving the polishing rate and uniformity of the polishing amount on the wafer surface.

[0102] Furthermore, by individually controlling the temperature, flow rate, type, etc. of the slurry flowing through the first path 304 and the second path 305 , the slurry supplied to the central area and the peripheral area of ​​the polishing pad 14 can be freely adjusted.

[0103] The third embodiment of the present application is described below:

[0104] like Figure 7 , which is a schematic diagram of a slurry flow control system 4 in a third embodiment. The slurry flow control system 4 includes a grinding device 1, a slurry circulation device 44, a control unit 46 and a flow monitor 47. Optionally, the grinding device 1 in the third embodiment may also have the same structure as the grinding device 1 in the first or second embodiment.

[0105] The grinding device 1 includes the grinding head unit 2 and the polishing plate unit 3 as described above. The first drive shaft 42 is the drive shaft of the polishing plate rotation spindle 16 and is also the rotation shaft of the polishing plate 14. The first motor 43 is used to drive the first drive shaft 42 to rotate. The second drive shaft 41 is the drive shaft of the grinding head 10 and is also the rotation shaft of the grinding head 10. The second motor 40 is used to drive the second drive shaft 41 to rotate.

[0106] The slurry circulation device 44 is also used to circulate the cooling medium in the slurry circulation plate 15. Optionally, only one slurry circulation device may be provided, and the cooling medium circulates in a plurality of paths separated from each other in the slurry circulation plate 15 through a common slurry circulation device, or a plurality of slurry circulation devices may be provided so that the cooling medium circulates separately with respect to each path.

[0107] The cooling medium circulation passage 45 is a passage for circulating the slurry between the slurry circulation plate 15 and the slurry circulation device 44. The cooling medium circulation passage 45 is provided with a slurry flow rate adjustment device 48 for adjusting the slurry flow rate. Optionally, the slurry flow rate adjustment device includes a solenoid valve.

[0108] The flow monitor 47 is used to monitor the flow of the slurry on the wafer surface. Optionally, the flow monitor 47 can be in any form as long as it is a device that can be used to detect the flow of the slurry. Optionally, during the CMP process, the flow monitor 47 can monitor the flow of the slurry in real time or intermittently. Then, the flow monitor 47 sends the flow information of the slurry on the polishing surface to the control unit 46.

[0109] The control unit 46 is configured to control the entire polishing device 1 , and is also configured to transmit and receive signals between the first motor 43 and the second motor 40 , the slurry circulation device 44 , the flow rate monitor 47 , and the slurry flow rate adjustment device 48 .

[0110] In one possible embodiment, the control unit 46 sends a signal to the slurry flow adjustment device 48 for uniformizing the deviation of the slurry amount on the polishing surface of the polishing plate or the surface of the chip based on the slurry flow information on the polishing surface of the polishing plate sent by the flow monitor 47, thereby adjusting the flow of the slurry supplied to the slurry circulation plate 15.

[0111] In addition, by sending the signal to the slurry circulation device 44, the concentration, temperature, type, etc. of the slurry can also be controlled. Next, a signal can be sent to the first motor 43 and the second motor 40 to control the rotation speed of the polishing plate or the grinding head.

[0112] Alternatively, the control unit 48 may be implemented by computer hardware or a combination of computer hardware and software. The software may be stored in a non-temporary storage medium as a program for executing a predetermined process and executed by a CPU in the computer hardware.

[0113] In summary, the wafer grinding apparatus provided in the present application can adjust the flow rate of the slurry on the grinding surface as the CMP process of the semiconductor wafer proceeds.

[0114] The present application is described in sufficient detail above with certain particularity. It should be understood by those skilled in the art that the description in the embodiments is merely exemplary, and all changes made without departing from the true spirit and scope of the present application should fall within the scope of protection of the present application. The scope of protection claimed in the present application is defined by the claims, rather than by the above description in the embodiments.

Claims

1. A wafer grinding device, characterized in that: The wafer grinding device comprises: a polishing plate, a slurry circulation plate, and a slurry circulation device, wherein: The polishing plate comprises a polishing surface, a back surface opposite to the polishing surface, and a plurality of slurry supply holes, wherein the polishing surface is used for polishing a wafer, and the plurality of slurry supply holes penetrate from the polishing surface to the back surface opposite to the polishing surface; The slurry circulation plate includes a path for circulating the slurry, a plurality of slurry supply ports on the path that are connected to the plurality of slurry supply holes in a one-to-one correspondence, a slurry injection port for injecting slurry into the path, and a slurry discharge port for discharging slurry from the path; The slurry circulation device is used to inject slurry into the slurry injection port and receive the slurry discharged from the slurry discharge port, thereby allowing the slurry to circulate on the path; The plurality of slurry supply ports supply slurry to the polishing surface through the plurality of slurry supply holes.

2. The wafer grinding device according to claim 1, characterized in that: The path is composed of a plurality of separated sub-paths, each of which is provided with a corresponding slurry supply port, a slurry injection port and a slurry discharge port.

3. The wafer grinding device according to claim 2, characterized in that: The plurality of separated sub-paths include at least a first path formed at a central portion of the slurry circulation plate and a second path formed at a peripheral portion of the slurry circulation plate.

4. The wafer grinding device according to claim 2, characterized in that: The multiple separated sub-paths are each connected to a corresponding slurry circulation device that is independently arranged. The different slurry circulation devices inject slurry into the corresponding sub-paths from the respectively connected slurry injection ports, and receive the discharged slurry from the respectively connected slurry discharge ports, thereby allowing the slurry to circulate on the corresponding sub-paths.

5. The wafer grinding device according to claim 1, characterized in that: The slurry injection port and the slurry discharge port are both located on the lower surface of the slurry circulation plate, the slurry supply port is located on the upper surface of the slurry circulation plate, and the slurry injection port, the slurry discharge port and the slurry supply port are all connected through the path.

6. The wafer grinding device according to claim 1, wherein: The path includes a plurality of first channels and second channels. The first channels are arranged in a circular ring or arc shape inside the slurry circulation plate. The second channels extend radially along the slurry circulation plate and are used to connect adjacent first channels.

7. The wafer grinding device according to claim 1, characterized in that: The slurry injection port and the slurry discharge port are respectively distributed on the path at equal distances; The slurry supply holes are equidistantly distributed in a circumferential shape on a plurality of concentric circles with the center of the polishing plate as the center.

8. The wafer grinding device according to claim 1, wherein: The slurry circulation device is also used to control at least one parameter of the type, concentration, temperature and flow rate of the slurry flowing into the slurry circulation plate.

9. The wafer grinding apparatus according to claim 1, wherein: The plurality of slurry supply holes are further provided with a cover plate with a variable opening size to adjust the flow rate of the slurry flowing out of the plurality of slurry supply holes.

10. A slurry flow control system, characterized in that: The slurry flow control system comprises a flow monitor, a control unit and a wafer grinding device as claimed in any one of claims 1 to 9, wherein: The flow monitor is used to monitor the flow of the slurry on the polishing surface in real time; The control unit controls the wafer polishing device to make the flow deviation of the slurry on the polishing surface uniform according to the output information of the flow monitor.

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