A cleaning device, system and method for the groove of the lower plate in double-sided grinding

Abstract

The embodiment of the present invention discloses a cleaning device, system and method for the grooves of the lower fixed plate in double-sided grinding, wherein the cleaning device comprises: a plurality of brushes arranged in a row, wherein the plurality of brushes can move in a set direction to clean particles in the grooves distributed laterally or longitudinally on the lower fixed plate; wherein each of the brushes consists of a brush handle and a brush head; and a plurality of high-pressure water spray pipes, wherein each of the high-pressure water spray pipes is correspondingly arranged directly behind the moving direction of each brush, so as to flush the particles in the grooves by spraying high-pressure pure water during the process of the plurality of brushes cleaning the particles.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of semiconductor manufacturing technology, and in particular to a cleaning device, system and method for cleaning grooves of a lower platen in double-sided grinding. Background Art

[0002] In the process of silicon wafer processing, in order to remove the line marks and mechanical damage layer on the surface of the silicon wafer after wire cutting, the silicon wafer will be subjected to a double-sided grinding process. In this process, the grinding slurry containing high-hardness abrasives (such as silicon oxide and aluminum oxide) contacts the surface of the silicon wafer sandwiched between the upper and lower fixed plates, and then the upper and lower fixed plates thin and grind the silicon wafer at a certain pressure and speed; a large amount of by-products such as silicon slag and grinding slurry residue will be produced during the double-sided grinding process. These by-products will be discharged from the grooves of the lower fixed plate, but after multiple processing, a large amount of solid by-products will accumulate in the grooves to cause the grooves to be blocked, and the silicon slag and grinding slurry residues retained between the fixed plates will scratch the surface of the silicon wafer during the double-sided grinding process, thereby causing the quality of the silicon wafer to decline, so the grooves of the lower fixed plate need to be cleaned regularly. The main cleaning method at present is to clean the grooves with a thin blade and then rinse the lower fixed plate with a water gun. However, the existing cleaning method not only consumes a lot of manpower and time, but also has low cleaning efficiency, and the thin blade may also damage the lower plate during the cleaning process. Summary of the invention

[0003] In view of this, embodiments of the present invention hope to provide a cleaning device, system and method for the grooves of the lower platen during double-sided grinding; the cleaning efficiency of the grooves of the lower platen can be improved, and at the same time, particulate matter in the grooves can be completely removed to ensure the quality of silicon wafers during double-sided grinding.

[0004] The technical solution of the embodiment of the present invention is achieved as follows:

[0005] In a first aspect, an embodiment of the present invention provides a cleaning device for a groove of a lower platen in double-sided grinding, the cleaning device comprising:

[0006] A plurality of brushes are arranged in a row, and the plurality of brushes can move in a set direction to clean particles in grooves distributed transversely or longitudinally on the lower plate; wherein each of the brushes is composed of a brush handle and a brush head;

[0007] A plurality of high-pressure water spray pipes are provided, each of which is correspondingly arranged directly behind the moving direction of each brush, so as to flush the particles in the groove by spraying high-pressure pure water during the process of the plurality of brushes cleaning the particles.

[0008] In a second aspect, an embodiment of the present invention provides a cleaning system for a groove of a lower platen in double-sided grinding, the cleaning system comprising:

[0009] A driving mechanism, the driving mechanism is used to control the cleaning device to move along a set direction at a certain speed to clean particles in the grooves distributed horizontally or vertically on the lower fixed plate;

[0010] The rotating mechanism is used to control the cleaning device to rotate 90° clockwise around the central axis of the rotating mechanism in sequence to complete the cleaning work of the grooves in all the set directions.

[0011] In a third aspect, an embodiment of the present invention provides a method for cleaning the grooves of a lower platen in double-sided grinding, the cleaning method can be applied to the cleaning system described in the second aspect, and the cleaning method comprises:

[0012] The cleaning device is driven by a driving mechanism to move along a set direction at a certain speed to clean particles in the grooves distributed horizontally or vertically on the lower fixed plate;

[0013] When the cleaning device completes the cleaning work in one of the set directions, the cleaning device is controlled by the rotating mechanism to rotate 90° clockwise around the central axis of the rotating mechanism in sequence, so that the cleaning device rotates to the next set direction and starts to clean the groove;

[0014] After the cleaning device completes the cleaning work of the groove along all the set directions, the cleaning device is controlled to rotate to the original position of the cleaning device through the rotating mechanism.

[0015] The embodiment of the present invention provides a cleaning device, system and method for the grooves of the lower fixed plate in double-sided grinding; the cleaning device mainly uses a plurality of brushes arranged in a row to simultaneously clean all the grooves in the horizontal or vertical direction on the lower fixed plate, and at the same time, during the process of the plurality of brushes cleaning the grooves, a high-pressure water spray pipe arranged directly behind the moving direction of each brush will spray high-pressure pure water, so that during the process of the plurality of brushes cleaning the particles in the grooves, the particles in the grooves are flushed by the high-pressure pure water, and at the same time, in the cleaning system provided by the embodiment of the present invention, the cleaning device can realize the movement and rotation of the cleaning device through a driving mechanism and a rotating mechanism to complete the cleaning of all the grooves distributed on the lower fixed plate; through this cleaning system, not only the cleaning efficiency of the grooves can be improved, but also the particles in the grooves can be completely removed, thereby improving the cleanliness of the grooves. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic cross-sectional view of a double-sided polishing device for a silicon wafer provided in an embodiment of the present invention.

[0017] Figure 2 A schematic diagram of the structure of a groove on a lower fixed plate provided in an embodiment of the present invention.

[0018] Figure 3 A schematic structural diagram of a cleaning device for the grooves of a lower platen in double-sided grinding provided by an embodiment of the present invention.

[0019] Figure 4 A schematic diagram of the positional relationship between the high-pressure water spray pipe and the brush provided in an embodiment of the present invention.

[0020] Figure 5 A schematic diagram of the angle between the direction in which high-pressure pure water is sprayed from the high-pressure water spray pipe provided in an embodiment of the present invention and the moving direction of the brush.

[0021] Figure 6 A schematic diagram of the minimum distance data between the bottom position of the brush head and the lower surface of the groove provided in an embodiment of the present invention.

[0022] Figure 7 A schematic diagram of the distance data after the change between the bottom position of the brush head and the lower surface of the groove provided in an embodiment of the present invention.

[0023] Figure 8 A schematic diagram of the position of a cleaning device when cleaning a groove along direction 1 and direction 2 provided by an embodiment of the present invention.

[0024] Fig. 9 A schematic diagram of the position of a cleaning device when cleaning a groove along direction 3 provided by an embodiment of the present invention.

[0025] Fig.10 A schematic diagram of the position of a cleaning device when cleaning a groove along direction 4 provided by an embodiment of the present invention.

[0026] Fig.11 A schematic flow chart of a method for cleaning grooves of a lower platen in double-sided grinding provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0028] See also Figure 1 , which shows a cross-sectional schematic diagram of a double-sided grinding device 1 commonly used for silicon wafers, the double-sided grinding device 1 may include a fixed plate 101, wherein the fixed plate 101 includes an upper fixed plate 101A and a lower fixed plate 101B, a carrier plate 102 and a control mechanism (not shown in the figure). Figure 2, which shows a plurality of transverse and longitudinal vertically staggered grooves 201 arranged in the lower platen 101B. It can be understood that in the double-sided grinding device 1, the upper platen 101A and the lower platen 101B are arranged opposite to each other, the carrier plate 102 is arranged between the upper platen 101A and the lower platen 101B, and a plurality of carrier plate holes 103 are arranged on the carrier plate 102, wherein the silicon wafer to be ground is placed in the carrier plate holes 103; under the action of the control mechanism, the carrier plate 102 can rotate around its own axis and revolve around the central axis of the lower platen 101B, so as to move relative to the upper platen 101A and the lower platen 101B to grind the silicon wafer to be ground. In addition, a plurality of carrier plates 102 may be disposed between the upper platen 101A and the lower platen 101B, and each carrier plate 102 is provided with a plurality of carrier plate holes 103, and a silicon wafer to be ground may be placed in each carrier plate hole 103, so that the double-sided grinding device 1 may grind a plurality of silicon wafers to be ground at the same time. It should be noted that Figure 1 The structure of the double-sided grinding device 1 shown is not specifically limited. In order to clearly illustrate the technical solution of the embodiment of the present invention, other components required for double-sided grinding of silicon wafers are omitted.

[0029] When the double-sided grinding device 1 is used to grind the double-sided of multiple silicon wafers, a large amount of byproducts such as silicon wafer residues and grinding slurry particles will be formed during the grinding process due to the mechanical reaction between the multiple silicon wafers and the grinding slurry and the friction between the platen 101 and the silicon wafers. These byproducts are mostly solid particles, which are difficult to be discharged directly from the edge of the lower platen 101B through the groove 201. With the recycling of the grinding slurry, these solid particles will continue to be recycled or accumulated in the groove 201 of the lower platen 101B, causing the groove 201 to have a problem of poor circulation. This problem will cause more and more silicon wafer residues and grinding slurry particles to accumulate in the groove 201, which will cause scratches on the surface of the silicon wafer during the double-sided grinding process, so that the quality of the double-sided ground silicon wafer will decrease.

[0030] Based on the above explanation, combined with Figure 3 and Figure 4 , which shows a cleaning device 3 for the groove 201 of the lower plate 101B in double-sided grinding provided by an embodiment of the present invention. The cleaning device 3 may specifically include:

[0031] A plurality of brushes 301 are arranged in a row, and the plurality of brushes 301 can move in a set direction to clean particles in the grooves 201 distributed transversely or longitudinally on the lower plate 101B; wherein each of the brushes 301 is composed of a brush handle 301A and a brush head 301B;

[0032] A plurality of high-pressure water spray pipes 302, each of which is correspondingly arranged in the moving direction of each brush 301 (such as Figure 4 The dotted arrow schematically shows the rear of the groove 201 , so that the particles in the groove 201 can be washed by spraying high-pressure pure water during the process of the plurality of brushes 301 cleaning the particles.

[0033] It is understandable that if Figure 3 As shown, the brush head 301B is fixedly disposed on one end of the brush handle 301A, and the other end of the brush handle 301A can be fixedly disposed on the housing 303.

[0034] The cleaning device 3 provided in the embodiment of the present invention can use a plurality of brushes 301 distributed in a row to move simultaneously in a set direction to clean the particles in all grooves 201 distributed horizontally or vertically on the lower fixed plate 101B. In the process of the brush 301 cleaning the particles in the groove 201, the high-pressure pure water is sprayed through the high-pressure water spray pipe 302 to flush the particles in the groove 201, so that the particles in the groove 201 are discharged from the lower fixed plate 101B along the groove 201 under the joint action of the brush 301 and the high-pressure pure water. Therefore, the cleaning device 3 uses a row of brushes 301 and high-pressure pure water to clean the particles in the groove 201 at the same time, shortening the cleaning time of the groove 201 and improving the cleaning efficiency of the groove 201; at the same time, the use of the brush 301 to clean the particles in the groove 201 will not cause damage to the lower fixed plate, saving production costs.

[0035] For the cleaning device 3 , in some examples, the length of the brush head 301B is greater than the depth of the groove 201 , and the shape of the brush head 301B is trapezoidal, so as to thoroughly clean the particles accumulated on the bottom and side walls of the groove 201 .

[0036] Preferably, for the above example, in some specific implementations, the brush head 301B is made of polyetheretherketone.

[0037] It should be noted that if Figure 4 As shown, the high-pressure water spray pipe 302 is composed of a high-pressure water spray port 302A and a high-pressure water spray pipeline 302B, wherein the high-pressure water spray pipeline 302B is connected to a pure water supply device (not shown in the figure).

[0038] In addition, in the embodiment of the present invention, in the process of the brush 301 cleaning the particles in the groove 201, in order to make the particles in the groove 201 be completely cleaned, for the cleaning device 3, in some examples, see Figure 4 and Figure 5 , the direction in which each high-pressure water spray pipe 302 sprays high-pressure pure water ( Figure 5 The angle between the moving direction of the brush 301 (shown by the solid arrow in the figure) and the moving direction of the brush 301 (shown by the dotted arrow in the figure) is an acute angle ( Figure 5α shown in , so that Figure 4 As shown, the high-pressure pure water sprayed by the high-pressure water nozzle 302A will form an inclined water column, and relative to the moving direction of the corresponding brush 301, the above-mentioned inclined water column can be sprayed forward and fall on the brush head 301B, so that while the brush head 301B cleans the particles, the high-pressure pure water sprayed obliquely forward can also provide a certain thrust to move the particles forward, which is conducive to completely discharging the particles in the groove 201 along the groove 201 to the lower fixed plate 101B.

[0039] For cleaning device 3, in some examples, see Figure 3 The cleaning device 3 further includes: a plurality of sensors 304 and a control unit 305 connected to the plurality of sensors 304; wherein,

[0040] Each sensor 304 is correspondingly disposed above each brush head 301B to sense the distance data between the bottom position of each brush head 301B and the lower surface of the groove 201;

[0041] The control unit 305 is configured to determine whether to trigger the high-pressure water spray pipe 302 corresponding to the brush head 301B to spray high-pressure pure water according to the distance data sensed by each sensor 304 .

[0042] It should be noted that if Figure 6 As shown, in the embodiment of the present invention, the minimum distance data between the bottom position of the brush head 301B and the lower surface of the groove 201 is set to L. It can be understood that, as Figure 7 As shown, when the brush head 301B enters the groove 201, the distance data l between the bottom position of the brush head 301B and the lower surface of the groove 201 will change, that is, l is less than the minimum distance data L. Therefore, in order to enable the high-pressure water spray pipe 302 to be turned on to spray high-pressure pure water when the brush head 301B enters the groove 201, in an embodiment of the present invention, a sensor is provided above each brush head 301B for sensing the distance data between the bottom position of the brush head 301B and the lower surface of the groove 201. When the sensed distance data is less than the minimum distance data L, it can be determined that the brush head 301B starts to clean the groove 201. At this time, the high-pressure water spray pipe 302 is triggered by the control unit 305 to spray high-pressure pure water; accordingly, when the brush head 301B completes the cleaning work and moves out of the groove 201, the distance data sensed by the sensor 304 will also change. At this time, the control unit 305 can control the high-pressure water spray pipe 302 to stop spraying water. In this case, production costs can be saved.

[0043] Preferably, for the cleaning device 3, in some examples, the sensor 304 is an eddy current sensor. It can be understood that in the embodiment of the present invention, the material of the lower plate 101B is cast iron, so when the sensor 304 uses an eddy current sensor that is sensitive to metal, when the distance data between the bottom position of the brush head 301B and the lower surface of the groove 201 changes, the sensor 304 can receive a signal and send a signal to the control unit 305, so that the control unit 305 controls the high-pressure water spray pipe 302 to start or stop spraying water according to the signal sent by the sensor 304.

[0044] In addition, the embodiment of the present invention further provides a cleaning system 10 for the groove 201 of the lower plate 101B in double-sided grinding, and the cleaning system 10 may specifically include:

[0045] The cleaning device 3 according to the aforementioned technical solution;

[0046] Figure 3 The driving mechanism 4 shown in the figure is used to control the cleaning device 3 to move at a certain speed along a set direction to clean the particles in the grooves distributed horizontally or vertically on the lower fixed plate;

[0047] Figure 8 The rotating mechanism 5 shown in the figure is used to control the cleaning device 3 to rotate 90° clockwise around the central axis of the rotating mechanism 5 in sequence to complete the cleaning work of the grooves in all the set directions.

[0048] Understandably, if Figure 8 As shown, during the cleaning process of the groove 201, the moving directions of the cleaning device 3 are set to four directions, namely direction 1, direction 2, direction 3 and direction 4, and the four directions are sequentially spaced 90° apart. In the embodiment of the present invention, the original position of the cleaning device 3 is set as Figure 8 The position shown by the solid line in the middle, when the cleaning device 3 is started, the cleaning device 3 first cleans the groove 201 along the direction 1, and the driving mechanism 4 can drive the cleaning device 3 to move at a constant speed along the direction 1. When the cleaning device 3 completes the cleaning work of the groove 201 along the direction 1, the cleaning device 3 moves to Figure 8 At the position indicated by the dotted line in the middle and lower part, the driving mechanism 4 brakes to stop the cleaning device 3 from moving; then, the rotating mechanism 5 controls the cleaning device 3 to rotate 90° clockwise, that is, the cleaning device 3 rotates to Figure 8 At the position indicated by the dotted line on the right side of the middle figure, the cleaning device 3 cleans the groove 201 along the direction 2 under the action of the driving mechanism 4.

[0049] Similarly, after the cleaning device 3 completes the cleaning work of the groove 201 along direction 2, the cleaning device 3 moves to Fig. 9At the position indicated by the dotted line on the left side of the figure, the driving mechanism 4 brakes to stop the cleaning device 3 from moving forward; then, the rotating mechanism 5 controls the cleaning device 3 to rotate 90° clockwise, that is, the cleaning device 3 rotates to Fig. 9 At the position indicated by the dotted line in the lower middle part, the cleaning device 3 cleans the groove 201 along direction 3 under the action of the driving mechanism 4 .

[0050] Similarly, after the cleaning device 3 completes the cleaning work of the groove 201 along the direction 3, the cleaning device 3 moves to Fig.10 At the position shown by the dotted line in the upper middle part, the driving mechanism 4 brakes to stop the cleaning device 3 from moving forward; then, the rotating mechanism 5 controls the cleaning device 3 to rotate 90° clockwise, that is, the cleaning device 3 rotates to Fig.10 At the position indicated by the dotted line on the left side, the cleaning device 3 cleans the groove 201 along the direction 4 under the action of the driving mechanism 4.

[0051] It can be seen that under the joint action of the driving mechanism 4 and the rotating mechanism 5, the cleaning device 3 cleans the groove 201 in direction 1, direction 2, direction 3 and direction 4 in sequence, and finally the cleaning device 3 can be moved to the groove 201 by rotating. Figure 8 The original position shown ( Figure 8 The position shown by the solid line in the middle), thus, the cleaning device 3 completes one cycle of cleaning work on the groove 201. It can be understood that after the cleaning device 3 performs one cycle of cleaning work on the groove 201, it is equivalent to cleaning all the grooves 201 distributed horizontally and / or vertically twice. Therefore, the above cleaning system 10 can not only improve the cleaning efficiency of the groove 201, but also completely remove the particles in the groove 201, thereby improving the cleanliness of the groove 201.

[0052] It should be noted that, in the process of cleaning the groove 201 along the above four directions, the moving direction of the brush 301 is always consistent with the forward direction of the cleaning device 3. Therefore, it can be understood that the water spraying direction of the high-pressure water spray pipe 302 is also always at an acute angle to the forward direction of the cleaning device 3.

[0053] For the cleaning system 10 , in some examples, the moving speed of the cleaning device 3 is 0.02 meters per second (m / s).

[0054] See also Fig.11 , which shows a cleaning method for the groove of the lower platen in double-sided grinding provided by an embodiment of the present invention, the cleaning method can be applied to the cleaning system 10 described in the above technical solution, and the cleaning method includes:

[0055] S1101, driving the cleaning device to move along a set direction at a certain speed through a driving mechanism to clean particles in grooves distributed horizontally or vertically on the lower fixed plate;

[0056] S1102, when the cleaning device completes the cleaning work in one of the set directions, the cleaning device is controlled by the rotating mechanism to rotate 90° clockwise around the central axis of the rotating mechanism in sequence, so that the cleaning device rotates to the next set direction and starts to clean the groove;

[0057] S1103, after the cleaning device completes the cleaning work of the groove along all the set directions, the cleaning device is controlled to rotate to the original position of the cleaning device through the rotating mechanism.

[0058] for Fig.11 In the technical solution shown in the figure, in some examples, the cleaning device is driven by the driving mechanism to move along a set direction at a certain speed to clean the particles in the grooves distributed horizontally or vertically on the lower fixed plate, including:

[0059] Controlling a plurality of brushes by the driving mechanism to clean the particles in the grooves distributed transversely or longitudinally on the lower fixed plate along the set direction;

[0060] When the plurality of brushes clean the particles, high-pressure pure water is sprayed through a high-pressure water spray pipe to wash the particles in the groove.

[0061] It should be noted that the technical solutions described in the embodiments of the present invention can be combined arbitrarily without conflict.

[0062] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A cleaning device for the groove of the lower plate in double-sided grinding, characterized in that: The cleaning device comprises: A plurality of brushes are arranged in a row, and the plurality of brushes can move in a set direction to clean particles in grooves distributed transversely or longitudinally on the lower plate; wherein each of the brushes is composed of a brush handle and a brush head; A plurality of high-pressure water spray pipes, each of which is correspondingly arranged directly behind each of the brushes in the moving direction, so as to flush the particles in the groove by spraying high-pressure pure water during the process of the plurality of brushes cleaning the particles; The angle between the direction in which each high-pressure water spraying pipe sprays high-pressure pure water and the moving direction of the corresponding brush is an acute angle, and the high-pressure pure water sprayed by each high-pressure water spraying pipe forms an inclined water column; In which, the cleaning device can move at a certain speed along the set direction to clean the particles in the grooves distributed horizontally or vertically on the lower fixed plate; and after completing the cleaning work in one of the set directions, the cleaning device can rotate 90° clockwise in sequence to rotate to the next set direction and start cleaning the grooves; wherein the cleaning device corresponds to four moving directions, and the four directions are spaced 90° apart in sequence.

2. The cleaning device according to claim 1, characterized in that The length of the brush head is greater than the depth of the groove, and the shape of the brush head is trapezoidal.

3. The cleaning device according to claim 2, characterized in that: The brush head is made of polyetheretherketone.

4. The cleaning device according to claim 1, characterized in that The cleaning device further comprises: a plurality of sensors and a control unit connected to the plurality of sensors; wherein, Each of the sensors is correspondingly arranged above each of the brush heads to sense the distance data between the bottom position of each of the brush heads and the lower surface of the groove; The control unit is configured to determine whether to trigger the high-pressure water spray pipe corresponding to the brush head to spray high-pressure pure water according to the distance data sensed by each of the sensors.

5. The cleaning device according to claim 4, characterized in that: The sensor is an eddy current sensor.

6. A cleaning system for the grooves of the lower plate in double-sided grinding, characterized in that: The cleaning system comprises: The cleaning device according to any one of claims 1 to 5; A driving mechanism, the driving mechanism is used to control the cleaning device to move along a set direction at a certain speed to clean particles in the grooves distributed horizontally or vertically on the lower fixed plate; The rotating mechanism is used to control the cleaning device to rotate 90° clockwise around the central axis of the rotating mechanism in sequence to complete the cleaning work of the grooves in all the set directions.

7. The cleaning system according to claim 6, characterized in that The moving speed of the cleaning device is 0.02 meters per second.

8. A method for cleaning a lower platen during double-sided grinding, characterized in that: The cleaning method can be applied to the cleaning system according to claim 6 or 7, and the cleaning method comprises: The cleaning device is driven by a driving mechanism to move along a set direction at a certain speed to clean particles in the grooves distributed horizontally or vertically on the lower fixed plate; When the cleaning device completes the cleaning work in one of the set directions, the cleaning device is controlled by the rotating mechanism to rotate 90° clockwise around the central axis of the rotating mechanism in sequence, so that the cleaning device rotates to the next set direction and starts to clean the groove; After the cleaning device completes the cleaning work of the groove along all the set directions, the cleaning device is controlled to rotate to the original position of the cleaning device through the rotating mechanism.

9. The cleaning method according to claim 8, characterized in that: The cleaning device is driven by a driving mechanism to move along a set direction at a certain speed to clean particles in the grooves distributed horizontally or vertically on the lower fixed plate, including: Controlling a plurality of brushes by the driving mechanism to clean the particles in the grooves distributed transversely or longitudinally on the lower fixed plate along the set direction; When the plurality of brushes clean the particles, high-pressure pure water is sprayed through a high-pressure water spray pipe to wash the particles in the groove.

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