Grinding pressure detection method

Abstract

The invention provides a grinding pressure detection method which comprises a grinding disc, a grinding pad and a polishing head, the grinding pad is arranged on the grinding disc and can rotate along with the grinding disc, the polishing head is arranged above the grinding pad, and the grinding pressure detection method comprises the following steps that the detection position of the grinding disc is set, a first preset distance is formed between the detection position and the rotating center of the grinding disc, a pressure detection device is arranged in the detection position, the pressure detection device is arranged below the grinding pad, and the pressure detection device can rotate around the axis of the grinding disc along with the grinding disc; according to the detection position of the grinding disc, the first grinding position of the polishing head is set, and the first grinding position can coincide with the detection position; and in the grinding process, the grinding pressure of the polishing head is obtained. The grinding pressure can be accurately detected while grinding is conducted.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a grinding pressure detection method. Background Art

[0002] CMP is a process in which the polishing head applies downward pressure on the back of the wafer and presses the front of the wafer onto a polishing pad made of a special material, thereby removing excess material on the front of the wafer and achieving flattening. There are multiple pressure zones on the polishing head, and different pressure control of each pressure zone is achieved by controlling different air pressures.

[0003] Currently, the grinding pressure is generally controlled indirectly by controlling the input air pressure of the pressure zone. However, in the actual grinding process, there is a certain difference between the grinding pressure applied to the wafer and the input air pressure. The input air pressure cannot accurately reflect the actual grinding pressure of the wafer. The lack of accurate data on the actual grinding pressure of the wafer will cause unevenness during wafer grinding, and the pressure cannot be adjusted in time, affecting the production quality of the wafer.

[0004] In addition, fluctuations in airflow will cause changes in the input air pressure, which in turn will cause changes in the grinding pressure of the wafer. Due to the lack of a detection device to directly measure the actual grinding pressure, changes in the grinding pressure cannot be discovered in time, and appropriate adjustments cannot be made in time. Summary of the invention

[0005] The object of the present invention is to provide a pressure detection method for accurately detecting grinding pressure while grinding.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a grinding pressure detection method, comprising a grinding device, the grinding device comprising a grinding disc, a grinding pad and a polishing head, the grinding pad is arranged on the grinding disc and can rotate with the grinding disc, the polishing head is arranged above the grinding pad, and the grinding pressure detection method comprises the following steps:

[0007] A detection position of the grinding disc is set, wherein a first preset distance is provided between the detection position and the rotation center of the grinding disc, a pressure detection device is provided in the detection position, the pressure detection device is provided below the grinding pad, and the pressure detection device can rotate around the axis of the grinding disc following the grinding disc;

[0008] According to the detection position of the grinding disc, the first grinding position of the polishing head is set, and the first grinding position can coincide with the detection position;

[0009] During the grinding process, the grinding pressure of the polishing head is obtained.

[0010] It can be seen from the above method that by arranging a pressure detection device under the grinding pad, it is convenient to directly detect the grinding pressure of the polishing head during the grinding process, which can more accurately reflect the actual grinding pressure of the wafer compared with the existing technology; by intermittently obtaining the grinding pressure of the polishing head during the grinding process, compared with the method of continuously obtaining detection data, it is conducive to reasonably streamlining the amount of detection data, saving time and energy for subsequent data analysis.

[0011] A further solution is to obtain the grinding pressure of the polishing head once at a first preset time interval according to the angular velocity of the grinding disc, and the first preset time is Where n1 is a positive integer and ω is the angular velocity of the grinding disc.

[0012] It can be seen from the above scheme that when the grinding disc rotates and the polishing head rotates around its own axis in the first grinding position, when the first preset time is separated, the first grinding position just completely coincides with the detection position, and the grinding pressure can be obtained at this time.

[0013] A further solution is that the value range of the first preset time is: [t1-Δt, t1+Δt], Where Δt is the error time, θ is the rotation angle of the grinding disc within the error time range, and ω is the angular velocity of the grinding disc.

[0014] A further solution is to set a second grinding position of the polishing head according to the first grinding position, the second grinding position is at a second preset distance from the first grinding position, and the polishing head can move back and forth in a straight line between the first grinding position and the second grinding position;

[0015] According to the angular velocity of the grinding disc and the moving distance of the polishing head, the grinding pressure of the polishing head is obtained once at a second preset time interval. The second preset time is and Wherein, n1 and n2 are both positive integers, ω is the angular velocity of the grinding disc, V1 is the moving speed of the polishing head, and L is the one-way moving distance of the polishing head.

[0016] It can be seen from the above scheme that when the grinding disc rotates, the polishing head rotates around its axis and moves back and forth between the first grinding position and the second grinding position. When the second preset time is exceeded, the polishing head is just in the first grinding position, and the first grinding position just completely coincides with the detection position. At this time, a grinding pressure can be obtained.

[0017] A further solution is that the value range of the second preset time is: [t2-Δt, t2+Δt], Wherein Δt is the error time, θ is the rotation angle of the grinding disc within the error time range, and ω is the angular velocity of the grinding disc.

[0018] A further solution is to obtain the grinding pressure of the polishing head at a preset number of full revolutions according to the number of revolutions of the grinding disc.

[0019] It can be seen from the above scheme that when the grinding disc rotates and the polishing head rotates around itself in the first grinding position and / or the polishing head moves back and forth in a straight line between the first grinding position and the second grinding position, when the preset number of full circles is reached, the polishing head is just located at the first grinding position and the first grinding position just coincides with the detection position, and a grinding pressure can be obtained at this time.

[0020] A further solution is that a plurality of pressure zones are arranged on the polishing head, and the plurality of pressure zones are arranged coaxially; a plurality of pressure detection devices are arranged in the detection position, and the plurality of pressure detection devices are arranged along the radial direction of the grinding disk, or arranged along a direction parallel to the tangential direction of the grinding disk, or arranged along a direction intersecting the radial direction of the grinding disk; when the detection position coincides with the first grinding position, the plurality of pressure detection devices correspond one by one to the plurality of pressure zones respectively.

[0021] It can be seen from the above scheme that by setting up multiple pressure detection devices corresponding to multiple pressure zones one by one, it is convenient to obtain the grinding pressures of multiple pressure zones respectively.

[0022] A further solution is that when the first grinding position coincides with the detection position, all pressure detection devices detect simultaneously, and the data measured at this time are valid data.

[0023] A further solution is that the grinding pressure detection method further comprises:

[0024] Before grinding, the initial rotation position of the grinding disc is fixed according to the detected position of the grinding disc;

[0025] Controlling the polishing head to drive the polishing object to move to just above the first polishing position;

[0026] Control the polishing head to drive the polishing object to move down to the first polishing position, at which time the first polishing position coincides with the detection position;

[0027] The grinding disc is controlled to rotate about its axis relative to the polishing head, and the polishing head is controlled to rotate about its own axis and / or to move back and forth linearly relative to the grinding disc.

[0028] It can be seen from the above scheme that the above arrangement is conducive to ensuring that the polishing head and the grinding object are both located in the detection position before the grinding disc rotates, so that the grinding pressure can be accurately obtained when needed.

[0029] A further solution is that the grinding device also includes a control module and a display module, the control module is used to receive and analyze the detection data of the pressure detection device, and the display module is used to display the analysis results in the form of numbers, graphics and / or tables.

[0030] It can be seen from the above scheme that, through the above setting, it is convenient to draw an analysis chart based on the obtained grinding pressure, which makes it convenient for the staff to read and adjust the relevant grinding parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of pressure zones of the polishing head in various embodiments of the present invention.

[0032] Figure 2 Schematic diagram of the grinding disc detection position in each embodiment of the present invention.

[0033] Figure 3 Schematic diagram of the grinding disc and the polishing head in the first embodiment of the present invention.

[0034] Figure 4 It is a flowchart of the first embodiment of the present invention.

[0035] Figure 5 Schematic diagram of a grinding disc and a polishing head in a second embodiment of the present invention.

[0036] Figure 6 It is a flowchart of the second embodiment of the present invention.

[0037] Figure 7 It is a flowchart of the third embodiment of the present invention.

[0038] Figure 8 It is a flowchart of the fourth embodiment of the present invention.

[0039] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0040] See also Figure 1 and Figure 2 The grinding pressure detection method of this embodiment includes a grinding device, which includes a grinding disc 2, a grinding pad (not shown in the figure) and a polishing head 1. The grinding pad is arranged on the grinding disc 2 and can rotate with the grinding disc 2. The polishing head 1 is arranged above the grinding pad. The polishing head 1 is used to adsorb the grinding object, that is, the wafer, onto the grinding pad, and apply a certain pressure to the wafer through the gas flow, so that the wafer is ground on the grinding pad. During grinding, the grinding disc 2 will drive the grinding pad to rotate around its axis, and the polishing head 1 can rotate around its own axis.

[0041] The polishing head 1 is provided with a plurality of pressure zones, which are arranged coaxially, and each pressure zone can independently apply pressure. This embodiment takes five pressure zones as an example. For the convenience of explanation, from the periphery of the polishing head 1 to its center, they are the retaining ring pressure zone P1, the first pressure zone Z1, the second pressure zone Z2, the third pressure zone Z3 and the fourth pressure zone Z4. The wafer (not shown in the figure) is adsorbed on the inner side of the retaining ring pressure zone P1, that is, the wafer covers the first pressure zone Z1, the second pressure zone Z2, the third pressure zone Z3 and the fourth pressure zone Z4.

[0042] A detection position 21 is provided on the grinding disc 2, and the detection position 21 is eccentrically arranged with respect to the grinding disc 2, and a first preset distance is provided between the detection position 21 and the rotation center of the grinding disc 2. A plurality of pressure detection devices are provided in the detection position 21, and the plurality of pressure detection devices are all arranged below the grinding pad. The plurality of pressure detection devices are arranged in one-to-one correspondence with the plurality of pressure partitions, and the detection range of each pressure detection device matches the shape of the corresponding pressure partition, and pressure detection can be performed when the pressure partition enters the detection range of the pressure detection device.

[0043] This embodiment takes five pressure detection devices as an example, namely, a first pressure detection device A1, a second pressure detection device A2, a third pressure detection device A3, a fourth pressure detection device A4 and a retaining ring pressure detection device N1. The five pressure detection devices are arranged along the radial direction of the grinding disc 2, or arranged along a direction parallel to the tangential direction of the grinding disc 2, or arranged along a direction intersecting the radial direction of the grinding disc 2, such as Figure 2 As shown. The detection range of the first pressure detection device A1 is set to a ring shape matching the first pressure zone Z1, the detection range of the second pressure detection device A2 is set to a ring shape matching the second pressure zone Z2, the detection range of the third pressure detection device A3 is set to a ring shape matching the third pressure zone Z3, the detection range of the fourth pressure detection device A4 is set to a circle shape matching the fourth pressure zone Z4, and the detection range of the retaining ring pressure detection device N1 is set to a ring shape matching the retaining ring pressure zone P1.

[0044] The grinding device also includes a control module and a display module. The control module is used to receive valid data from each pressure detection device and perform data analysis, and the display module is used to display the analysis results in the form of numbers, graphics and / or tables.

[0045] The first embodiment of the grinding pressure detection method:

[0046] See also Figure 3 and Figure 4The present embodiment provides a grinding pressure detection method. During the grinding process, the grinding disc 2 rotates around its own axis and the polishing head 1 rotates around its own axis. The grinding pressure detection method includes the following steps:

[0047] S1: Set the detection position 21 of the grinding disk 2, and there is a first preset distance between the detection position 21 and the rotation center of the grinding disk 2. The first preset distance can be zero or a positive number; five pressure detection devices are arranged in the detection position 21, and the five pressure detection devices are arranged under the grinding pad. The five pressure detection devices can rotate around the axis of the grinding disk 2 with the grinding disk 2.

[0048] S2: According to the detected position 21 of the grinding disc 2, the initial rotation position of the grinding disc 2 is fixed. At this time, the grinding disc 2 is fixed and does not rotate, so as to prepare for the subsequent polishing head 1 to move the wafer into the grinding chamber.

[0049] S3: According to the detection position 21 of the grinding disc 2, the first grinding position 11 of the polishing head 1 is set, and the first grinding position 11 can coincide with the detection position 21. Specifically, at the initial position of rotation, the first grinding position 11 coincides with the detection position 21, and when the grinding disc 2 rotates, the first grinding position 11 coincides with the detection position 21 intermittently.

[0050] S4: Control the polishing head 1 to absorb the wafer and move the wafer to just above the first grinding position 11.

[0051] S5: Control the polishing head 1 to drive the wafer to move to the first grinding position 11 along the vertical direction, and apply pressure to multiple locations of the wafer through multiple pressure zones.

[0052] S6: Control the grinding disc 2 to rotate around its own axis so that the grinding pad on the grinding disc 2 grinds the wafer, and during the grinding process, the polishing head 1 can rotate around its own axis, and the rotation direction of the polishing head 1 is the same as the rotation direction of the grinding disc 2. Preferably, the grinding disc 2 and the polishing head 1 rotate at a uniform speed.

[0053] In this embodiment, step S6 and step S5 can be arranged sequentially or interchangeably.

[0054] S7: According to the angular velocity of the grinding disc 2, the grinding pressure of the polishing head 1 is obtained once at a first preset time interval. Specifically:

[0055] During the grinding process, the grinding disc 2 rotates counterclockwise at a constant speed. After a first preset time, the first grinding position 11 and the detection position 21 coincide with each other again. At this time, the five pressure detection devices are just opposite to the corresponding pressure zones. The first preset time is Wherein, n1 is a positive integer, and ω is the angular velocity of the grinding disc 2 .

[0056] For example: when the grinding disc 2 starts to rotate, the time is set to t0. When the first preset time t1 is passed, the detection position 21 of the grinding disc 2 just completely overlaps with the first grinding position 11. At this time, the first pressure detection device A1 can just detect the grinding pressure of the first pressure zone Z1, the second pressure detection device A2 can just detect the grinding pressure of the second pressure zone Z2, the third pressure detection device A3 can just detect the grinding pressure of the third pressure zone Z3, the fourth pressure detection device A4 can just detect the grinding pressure of the fourth pressure zone Z4, and the retaining ring pressure detection device N1 can just detect the grinding pressure of the retaining ring pressure zone P1. After that, each pressure detection device obtains the grinding pressure again at every interval of the first preset time t1. Of course, the grinding pressure can also be obtained once at intervals of integer multiples of the first preset time t1.

[0057] In order to improve the accuracy of the detection data, in this embodiment, the value range of the first preset time t1 is: [t1-Δt, t1+Δt], Where Δt is the error time, θ is the rotation angle of the grinding disc within the error time range, and ω is the angular velocity of the grinding disc. Preferably, the value range of θ is: [-10°, 10°]. For example: when θ is equal to -10°,

[0058] The pressure detection device may be activated only when it is necessary to obtain detection data, or the pressure detection device may be in a real-time detection state. The latter is preferred in this embodiment.

[0059] The second embodiment of the grinding pressure detection method:

[0060] See also Figure 5 and Figure 6 The present embodiment provides a grinding pressure detection method. During the grinding process, the grinding disc 2 rotates around its own axis, and the polishing head 1 rotates around its own axis while moving back and forth linearly relative to the grinding disc 2. The pressure detection method includes the following steps:

[0061] S10: Set the detection position 21 of the grinding disk 2, and there is a first preset distance between the detection position 21 and the rotation center of the grinding disk 2. The first preset distance can be zero or a positive number. A pressure detection device is provided in the detection position 21. The pressure detection device is provided below the grinding pad. The pressure detection device can rotate around the axis of the grinding disk 2 following the grinding disk 2.

[0062] S20: According to the detected position 21 of the grinding disc 2, the initial rotation position of the grinding disc 2 is fixed. At this time, the grinding disc 2 is fixed and does not rotate, so as to prepare for the subsequent polishing head 1 to move the wafer into the grinding chamber.

[0063] S30: According to the detection position 21 of the grinding disc 2, the first grinding position 11 and the second grinding position 12 of the polishing head 1 are set, the second grinding position 12 and the first grinding position 11 have a second preset distance, and the first grinding position 11 can overlap with the detection position 21. Specifically, at the initial rotation position, the first grinding position 11 overlaps with the detection position 21, and when the grinding disc 2 rotates, the first grinding position 11 overlaps with the detection position 21 intermittently.

[0064] S40: Control the polishing head 1 to absorb the wafer and move the wafer to just above the first grinding position 11.

[0065] S50: Control the polishing head 1 to drive the wafer to move to the first grinding position 11 along the vertical direction, and apply pressure to multiple locations of the wafer through multiple pressure zones.

[0066] S60: Control the grinding disc 2 to rotate around its own axis, and control the polishing head 1 to rotate around its own axis while moving back and forth between the first grinding position 11 and the second grinding position 12 in a straight line, so that the grinding pad on the grinding disc 2 grinds the wafer. Preferably, the one-way moving distance of the polishing head 1 is equal to the second preset distance, the grinding disc 2 and the polishing head 1 rotate at a uniform speed, and the polishing head 1 moves in a straight line at a uniform speed.

[0067] In this embodiment, step S60 and step S50 can be arranged sequentially or interchangeably.

[0068] S70: According to the angular velocity of the grinding disc 2 and the moving distance of the polishing head 1, the grinding pressure of the polishing head 1 is obtained once at a second preset time interval. Specifically:

[0069] During the grinding process, the grinding disc 2 rotates counterclockwise at a constant speed, and the polishing head 1 moves back and forth between the first grinding position 11 and the second grinding position 12 at a constant speed. When the second preset time is passed, the polishing head 1 is just located in the first grinding position 11, and the first grinding position 11 coincides with the detection position 21 again, the second preset time is and Wherein, n1 and n2 are both positive integers, ω is the angular velocity of the grinding disc 2 , V1 is the moving speed of the polishing head 1 , and L is the one-way moving distance of the polishing head 1 .

[0070] For example: when the grinding disc 2 starts to rotate, the time is set to t0. When the second preset time t2 is passed, the polishing head 1 drives the wafer to be located in the first grinding position 11, and the detection position 21 of the grinding disc 2 just completely overlaps with the first grinding position 11. At this time, the first pressure detection device A1 can just detect the grinding pressure of the first pressure zone Z1, the second pressure detection device A2 can just detect the grinding pressure of the second pressure zone Z2, the third pressure detection device A3 can just detect the grinding pressure of the third pressure zone Z3, the fourth pressure detection device A4 can just detect the grinding pressure of the fourth pressure zone Z4, and the retaining ring pressure detection device N1 can just detect the grinding pressure of the retaining ring pressure zone P1. Thereafter, each pressure detection device obtains the grinding pressure again at every interval of the second preset time t2. Of course, the grinding pressure can also be obtained once at intervals of integer multiples of the second preset time t2.

[0071] The pressure detection device may be activated only when it is necessary to obtain detection data, or the pressure detection device may be in a real-time detection state. The latter is preferred in this embodiment.

[0072] The third embodiment of the grinding pressure detection method:

[0073] Combination Figure 3 and Figure 7 This embodiment provides a grinding pressure detection method. During the grinding process, the grinding disc 2 rotates around its own axis and the polishing head 1 rotates around its own axis. The pressure detection method includes the following steps:

[0074] S100: Set the detection position 21 of the grinding disk 2, and there is a first preset distance between the detection position 21 and the rotation center of the grinding disk 2. The first preset distance can be zero or a positive number. A pressure detection device is provided in the detection position 21. The pressure detection device is provided below the grinding pad. The pressure detection device can rotate around the axis of the grinding disk 2 following the grinding disk 2.

[0075] S200: According to the detection position 21 of the grinding disc 2, the initial rotation position of the grinding disc 2 is fixed. At this time, the grinding disc 2 is fixed and does not rotate, so as to prepare for the subsequent polishing head 1 to move the wafer into the grinding chamber.

[0076] S300: According to the detection position 21 of the grinding disc 2, the first grinding position 11 of the polishing head 1 is set, and at this time, the first grinding position 11 coincides with the detection position 21. Specifically, at the initial rotation position, the first grinding position 11 coincides with the detection position 21, and when the grinding disc 2 rotates, the first grinding position 11 coincides with the detection position 21 intermittently.

[0077] S400: Control the polishing head 1 to absorb the wafer and move the wafer to just above the first grinding position 11.

[0078] S500: Control the polishing head 1 to move the wafer to the first grinding position 11 in the vertical direction, and apply pressure to multiple locations of the wafer through multiple pressure zones.

[0079] S600: Control the grinding disc 2 to rotate around its own axis so that the grinding pad on the grinding disc 2 grinds the wafer, and the polishing head 1 can rotate around its own axis during the grinding process. The rotation direction of the polishing head 1 is the same as the rotation direction of the grinding disc 2. Preferably, the grinding disc 2 and the polishing head 1 rotate at a uniform speed.

[0080] In this embodiment, step S6 and step S5 can be arranged sequentially or interchangeably.

[0081] S700: According to the number of revolutions of the grinding disc 2, the grinding pressure of the polishing head 1 is obtained at intervals of a preset number of revolutions. The preset number of revolutions can be a whole number of revolutions or a number of revolutions with a decimal. The former is preferred in this embodiment. Specifically:

[0082] During the grinding process, the grinding disc 2 rotates at a constant speed, or at a variable speed, which is not limited here. The polishing head 1 preferably rotates at a constant speed.

[0083] When the preset number of full revolutions is reached, the first grinding position 11 and the detection position 21 coincide with each other again, and the grinding pressure of the polishing head 1 can be obtained at this time.

[0084] For example: when the grinding disc 2 starts to rotate, the number of rotations is set to 0. When the interval is a preset number of full turns X, the detection position 21 of the grinding disc 2 just completely overlaps with the first grinding position 11. At this time, the first pressure detection device A1 can just detect the grinding pressure of the first pressure zone Z1, the second pressure detection device A2 can just detect the grinding pressure of the second pressure zone Z2, the third pressure detection device A3 can just detect the grinding pressure of the third pressure zone Z3, the fourth pressure detection device A4 can just detect the grinding pressure of the fourth pressure zone Z4, and the retaining ring pressure detection device N1 can just detect the grinding pressure of the retaining ring pressure zone P1. After that, each pressure detection device obtains the grinding pressure again at every interval of full turns X.

[0085] The fourth embodiment of the grinding pressure detection method:

[0086] Combination Figure 5 and Figure 8 The present embodiment provides a grinding pressure detection method. During the grinding process, the grinding disc 2 rotates around its own axis, and the polishing head 1 rotates around its own axis while moving back and forth linearly between a first grinding position and a second grinding position. The pressure detection method includes the following steps:

[0087] S1000: Set the detection position 21 of the grinding disk 2, there is a first preset distance between the detection position 21 and the rotation center of the grinding disk 2, the first preset distance can be zero or a positive number; a pressure detection device is arranged in the detection position 21, the pressure detection device is arranged under the grinding pad, and the pressure detection device can rotate around the axis of the grinding disk 2 with the grinding disk 2.

[0088] S2000: According to the detection position 21 of the grinding disc 2, the initial rotation position of the grinding disc 2 is fixed. At this time, the grinding disc 2 is fixed and does not rotate, in preparation for the subsequent polishing head 1 to move the wafer into the grinding chamber.

[0089] S3000: According to the detection position 21 of the grinding disc 2, the first grinding position 11 and the second grinding position 12 of the polishing head 1 are set, and there is a second preset distance between the second grinding position 12 and the first grinding position 11, and the second preset distance is a positive number; the first grinding position 11 can overlap with the detection position 21. Specifically, at the initial position of rotation, the first grinding position 11 overlaps with the detection position 21, and when the grinding disc 2 rotates, the first grinding position 11 overlaps with the detection position 21 intermittently.

[0090] S4000: Control the polishing head 1 to adsorb the wafer and move the wafer to just above the first grinding position 11.

[0091] S5000: Control the polishing head 1 to move the wafer to the first grinding position 11 in the vertical direction, and apply pressure to multiple locations of the wafer through multiple pressure zones.

[0092] S6000: Control the grinding disc 2 to rotate around its own axis, and control the polishing head 1 to rotate around its own axis while moving back and forth between the first grinding position 11 and the second grinding position 12 in a straight line, so that the grinding pad on the grinding disc 2 grinds the wafer. Preferably, the one-way moving distance of the polishing head 1 is equal to the second preset distance, the grinding disc 2 and the polishing head 1 rotate at a uniform speed, and the polishing head 1 moves in a straight line at a uniform speed.

[0093] In this embodiment, step S60 and step S50 can be arranged sequentially or interchangeably.

[0094] S7000: According to the number of revolutions of the grinding disc 2, the grinding pressure of the polishing head 1 is obtained at intervals of a preset number of revolutions. The preset number of revolutions can be a whole number of revolutions or a number of revolutions with a decimal. The former is preferred in this embodiment. Specifically:

[0095] During the grinding process, the grinding disc 2 rotates at a constant speed, or at a variable speed, which is not limited here. The polishing head 1 preferably rotates at a constant speed, and the polishing head 1 moves linearly at a constant speed.

[0096] When the preset number of full circles is passed, the first grinding position 11 and the detection position 21 coincide with each other again, and the polishing head 1 is just located in the first grinding position 11 , the grinding pressure of the polishing head 1 can be obtained at this time.

[0097] For example: when the grinding disc 2 starts to rotate, the number of rotations is set to 0. When the interval is a preset number of full turns X, the detection position 21 of the grinding disc 2 just completely overlaps with the first grinding position 11, and the polishing head 1 is just located in the first grinding position 11. At this time, the first pressure detection device A1 can just detect the grinding pressure of the first pressure zone Z1, the second pressure detection device A2 can just detect the grinding pressure of the second pressure zone Z2, the third pressure detection device A3 can just detect the grinding pressure of the third pressure zone Z3, the fourth pressure detection device A4 can just detect the grinding pressure of the fourth pressure zone Z4, and the retaining ring pressure detection device N1 can just detect the grinding pressure of the retaining ring pressure zone P1. After that, each pressure detection device obtains the grinding pressure again at every interval of full turns X.

[0098] In summary, it can be seen that the present invention arranges a pressure detection device under the grinding pad to facilitate the detection of the grinding pressure of the polishing head 1 during the grinding process. Compared with the prior art, it can more accurately reflect the actual grinding pressure of the wafer; by obtaining the grinding pressure of the polishing head 1 only when the first grinding position 11 coincides with the detection position 21, compared with the continuous detection method, it is beneficial to reasonably streamline the amount of detection data, saving time and energy for subsequent data analysis.

[0099] Finally, it should be emphasized that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A grinding pressure detection method, comprising a grinding device, wherein the grinding device comprises a grinding disc, a grinding pad and a polishing head, wherein the grinding pad is arranged on the grinding disc and can rotate with the grinding disc, and the polishing head is arranged above the grinding pad, characterized in that: The grinding pressure detection method comprises the following steps: A detection position of the grinding disk is set, wherein a first preset distance exists between the detection position and the rotation center of the grinding disk, a pressure detection device is arranged in the detection position, the pressure detection device is arranged below the grinding pad, and the pressure detection device can rotate around the axis of the grinding disk following the grinding disk; According to the detected position of the grinding disc, a first grinding position of the polishing head is set, and the first grinding position may coincide with the detected position; During the grinding process, the grinding pressure of the polishing head is obtained.

2. The grinding pressure detection method according to claim 1, characterized in that: According to the angular velocity of the grinding disk, the grinding pressure of the polishing head is obtained once at a first preset time interval, and the first preset time is Wherein, n1 is a positive integer, and ω is the angular velocity of the grinding disc.

3. The grinding pressure detection method according to claim 2, characterized in that: The value range of the first preset time is: [t1-Δt, t1+Δt], Wherein Δt is the error time, θ is the rotation angle of the grinding disc within the error time range, and ω is the angular velocity of the grinding disc.

4. The grinding pressure detection method according to claim 1, characterized in that: According to the first grinding position, setting the second grinding position of the polishing head, the second grinding position and the first grinding position have a second preset distance between them, and the polishing head can move back and forth in a straight line between the first grinding position and the second grinding position; According to the angular velocity of the grinding disc and the moving distance of the polishing head, the grinding pressure of the polishing head is obtained once at a second preset time interval, and the second preset time is and Wherein, n1 and n2 are both positive integers, ω is the angular velocity of the grinding disc, V1 is the moving speed of the polishing head, and L is the one-way moving distance of the polishing head.

5. The grinding pressure detection method according to claim 4, characterized in that: The value range of the second preset time is: [t2-Δt, t2+Δt], Wherein Δt is the error time, θ is the rotation angle of the grinding disc within the error time range, and ω is the angular velocity of the grinding disc.

6. The grinding pressure detection method according to claim 1, characterized in that: According to the number of rotations of the grinding disc, the grinding pressure of the polishing head is obtained once at a preset number of rotations.

7. The grinding pressure detection method according to any one of claims 1 to 6, characterized in that: The polishing head is provided with a plurality of pressure zones, and the plurality of pressure zones are coaxially arranged; A plurality of the pressure detection devices are arranged in the detection position, and the plurality of the pressure detection devices are arranged along the radial direction of the grinding disc, or arranged along a direction parallel to the tangential direction of the grinding disc, or arranged along a direction intersecting the radial direction of the grinding disc; When the detection position coincides with the first grinding position, the plurality of pressure detection devices correspond one-to-one to the plurality of pressure zones, respectively.

8. The grinding pressure detection method according to claim 7, characterized in that: When the first grinding position coincides with the detection position, all the pressure detection devices detect simultaneously, and the data measured at this time are valid data.

9. The grinding pressure detection method according to any one of claims 1 to 6, characterized in that: The grinding pressure detection method also includes: Before grinding, fixing the initial rotation position of the grinding disc according to the detected position of the grinding disc; Controlling the polishing head to drive the polishing object to move to just above the first polishing position; Controlling the polishing head to drive the polishing object to move down to the first polishing position, at which time, the first polishing position coincides with the detection position; The grinding disc is controlled to rotate around its axis, and the polishing head is controlled to rotate around its own axis and / or to move back and forth linearly relative to the grinding disc.

10. The grinding pressure detection method according to any one of claims 1 to 6, characterized in that: The grinding device further comprises a control module and a display module. The control module is used to receive and analyze the detection data of the pressure detection device, and the display module is used to display the analysis results in the form of numbers, graphics and / or tables.

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