Polishing apparatus dressing method, polishing apparatus, and chemical mechanical polishing apparatus

Abstract

This invention provides a polishing device dressing method, a polishing device, and a chemical mechanical polishing (CMP) apparatus. The polishing device includes a polishing pad and a dressing device, wherein the dressing device is equipped with a dressing head corresponding to the polishing pad. The dressing method includes: obtaining the wear amount at various positions of the polishing pad; dividing the surface of the polishing pad into multiple dressing regions based on the diameter of the dressing head, and selecting one of the dressing regions as a reference dressing region; calculating a first average wear amount in each dressing region based on the wear amount; and adjusting the rotational speed of the dressing head within each dressing region based on the correspondence between the first average wear amount of each dressing region and the reference dressing region. By changing the rotational speed of the dressing head, the non-uniformity generated on the surface of the polishing pad during the polishing process is eliminated. The rotational speed adjustment process of the dressing head is relatively fast and has the advantage of short delay, resulting in a better dressing effect on the surface of the polishing pad.

Description

Technical Field

[0001] This invention relates to the technical field of chemical mechanical polishing (CMP) of wafers, specifically to a polishing device dressing method, a polishing device, and a CMP equipment. Background Technology

[0002] Chemical mechanical polishing (CMP) equipment is mainly used for wafer planarization processes. The wafer and polishing pad move relative to each other in a polishing slurry environment, relying on chemical etching and mechanical friction to achieve wafer planarization. During the wafer polishing process, the polishing pad experiences wear. Because the relative movement trajectory between the polishing pad and the wafer is uneven, the amount of wear on the polishing pad surface is also uneven. This unevenness on the polishing pad surface can easily cause polishing defects on the wafer surface. Therefore, a dressing device is needed to real-time dress the polishing pad surface to eliminate this unevenness.

[0003] In existing technologies, during the swinging process of the dressing device, the operator often sets the pressure of the dressing head at different positions on the polishing pad based on experience in order to reduce the unevenness of the polishing pad wear. However, the pressure of the dressing head on the polishing pad is applied by a cylinder or air bag, and the process of changing the pressure has a certain delay, resulting in poor dressing effect. Summary of the Invention

[0004] Therefore, in order to overcome the shortcomings of the prior art in terms of poor effect on the surface unevenness of polishing pads, the present invention provides a polishing device trimming method, a polishing device, and a chemical mechanical polishing device.

[0005] In a first aspect, the present invention provides a method for dressing a polishing apparatus, the polishing apparatus comprising a polishing pad and a dressing device, the dressing device being configured with a dressing head corresponding to the polishing pad, the dressing method comprising the following steps:

[0006] Obtain the wear amount at each position of the polishing pad;

[0007] Based on the diameter of the dressing head, the surface of the polishing pad is divided into multiple dressing areas, and one of the dressing areas is selected as the reference dressing area.

[0008] Calculate the first average loss amount in each of the trimming areas based on the loss amount;

[0009] Based on the correspondence between the first average loss of each trimming region and the reference trimming region, the rotational speed of the trimming head in each trimming region is adjusted.

[0010] Optionally, adjusting the rotational speed of the dressing head within each of the dressing regions based on the correspondence between the first average loss of each dressing region and the reference dressing region includes:

[0011] The dressing head is located in a dressing region. If it is located in the reference dressing region, the rotation speed of the dressing head in the reference dressing region is adjusted to the first reference rotation speed. If it is located in another dressing region, the first ratio of the first average loss of the dressing region to the first average loss of the reference dressing region is calculated, and the rotation speed of the dressing head in the other dressing region is adjusted based on the first ratio and the first reference rotation speed.

[0012] Optionally, determining the trimming area where the trimming head is located includes:

[0013] A reference coordinate system is established on the surface of the polishing pad with the center of the polishing pad as the origin;

[0014] Determine the first coordinate value of the support axis of the trimming device in the reference coordinate system;

[0015] Obtain the rotation angle of the polishing pad, and calculate the real-time coordinate system after the rotation of the reference coordinate system;

[0016] Obtain the swing angle of the dressing arm of the polishing device, and calculate the second coordinate value of the dressing head in the real-time coordinate system based on the axial distance between the support shaft and the dressing head.

[0017] Based on the second coordinate value, the absolute position of the trimming head on the polishing pad is determined, and the trimming area where the trimming head is located is obtained.

[0018] Optionally, obtaining the wear amount at each location of the polishing pad includes:

[0019] During the process of obtaining the dressing head dressing the polishing pad, the amount of displacement in the direction perpendicular to the surface of the polishing pad at each of the said positions;

[0020] Based on the displacement, the wear of the trimming head at each position on the polishing pad is calculated.

[0021] Optionally, selecting one of the trimming areas as the reference trimming area includes:

[0022] Compare the magnitude of the first average loss in each of the described trimming areas;

[0023] The trimming area with the largest or smallest average loss is selected as the reference trimming area.

[0024] Optionally, the trimming method further includes:

[0025] Determine whether the trimming head has moved to an abnormal area;

[0026] When the trimming head moves to the abnormal area, the rotational speed of the trimming head is adjusted based on the second average loss of the abnormal area;

[0027] The process of determining the abnormal region includes:

[0028] Multiple detection areas are divided within the same trimming area;

[0029] Calculate the second average loss for each of the detection regions;

[0030] Determine whether the second average loss within the same trimming area exceeds a preset abnormal threshold.

[0031] If the second average loss exceeds the preset abnormal threshold, the detection area corresponding to the second average loss is set as an abnormal area.

[0032] Optionally, determining whether the second average loss exceeds a preset abnormal threshold includes:

[0033] Calculate the absolute value of the difference between the second average loss of the detection area and the first average loss of the trimming area where the detection area is located.

[0034] Calculate the second ratio of the absolute value to the first average loss;

[0035] Determine whether the second ratio exceeds the abnormal threshold.

[0036] Optionally, adjusting the rotational speed of the dressing head based on the second average loss amount in the abnormal region includes:

[0037] The rotational speed of the trimming head in the trimming area where the abnormal area is located is taken as the second reference rotational speed.

[0038] Calculate the third ratio between the first average loss of the repair area where the abnormal area is located and the second average loss of the abnormal area.

[0039] When the trimming head moves into the abnormal area, the speed of the trimming head is adjusted based on the second reference speed and the third ratio.

[0040] Secondly, the present invention provides a polishing apparatus, wherein the polishing apparatus uses the polishing apparatus trimming method described in any of the above embodiments to trim a polishing pad.

[0041] Thirdly, the present invention also provides a chemical mechanical polishing apparatus, which includes the polishing device described in any of the above embodiments.

[0042] The technical solution of this invention has the following advantages:

[0043] 1. The dressing method provided by the present invention acquires the wear amount at each position of the polishing pad at all times, and adjusts the rotation speed of the dressing head according to the magnitude of the first average wear amount in the dressing area when the dressing head enters different dressing areas. This causes the dressing head to slow down in the dressing area with a large first average wear amount and speed up in the dressing area with a small first average wear amount, thereby eliminating the unevenness generated by the polishing pad during the grinding process. The speed adjustment process of the dressing head is faster, the delay time of the control process is shorter, and the dressing effect on the surface of the polishing pad is better.

[0044] 2. The dressing method provided by the present invention selects a reference dressing area, adapts the dressing head to the corresponding rotation speed when dressing in the reference dressing area, and then adjusts the rotation speed of the dressing head according to the first ratio of the first average loss of each other dressing area to the reference dressing area, so that the control of the dressing head rotation speed is more reasonable and can better adapt to the first average loss of each dressing area.

[0045] 3. The dressing method provided by the present invention divides the same dressing area into multiple detection areas and compares the second average loss of each detection area with the first average loss of the dressing area to find abnormal areas with abnormal protrusions or depressions on the surface of the polishing pad. This allows the dressing head to eliminate abnormal parts by adjusting the rotation speed when entering the abnormal area, thereby further improving the dressing effect on the surface of the polishing pad.

[0046] 4. The dressing method provided by the present invention utilizes a reference coordinate system established on the surface of the polishing pad to obtain a real-time coordinate system through the rotation angle of the polishing pad. This allows for accurate calculation of the absolute position of the polishing head on the surface of the polishing pad at any given time. The calculation method is simple and reliable, and the process of obtaining the position of the polishing head is short, further reducing the delay in adjusting the rotation speed of the polishing head.

[0047] 5. The polishing device provided by the present invention adjusts the rotation speed of the dressing head to dress the surface of the polishing pad, which has the advantages of small delay and better dressing effect, and better effect on reducing the unevenness of the polishing pad surface.

[0048] 6. The chemical mechanical polishing equipment provided by the present invention uses a polishing pad prepared by the polishing device of the above-mentioned preparation method to grind and polish the wafer. The surface unevenness of the polishing pad is small, which can better grind and polish the wafer and improve the finished product quality of the wafer. Attached Figure Description

[0049] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the polishing device provided in an embodiment of the present invention;

[0051] Figure 2 This is a flowchart of the polishing method of the polishing apparatus provided in the embodiments of the present invention;

[0052] Figure 3 This is a schematic diagram of the structure for dividing the polishing pad surface into trimming areas in an embodiment of the present invention;

[0053] Figure 4 This is a schematic diagram of the structure for dividing the polishing pad surface trimming area into detection areas in an embodiment of the present invention.

[0054] Explanation of reference numerals in the attached figures:

[0055] 1. Polishing pad; 2. Polishing table; 3. First motor; 4. First encoder; 5. Fixing ring; 6. Fixing shaft; 7. Support shaft; 8. Second motor; 9. Second encoder; 10. Trimming arm; 11. Trimming shaft; 12. Trimming head; 13. Sensor; 14. Monitoring device; 15. Third motor; 16. Pressure device. Detailed Implementation

[0056] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0058] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0059] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0060] This embodiment provides a method for dressing a polishing apparatus. (Refer to...) Figure 1 As shown, the polishing apparatus includes: a polishing pad 1, a polishing table 2, a first motor 3, a fixing ring 5, a fixing shaft 6, and a dressing device. The polishing pad 1 is connected to the polishing table 2. The first motor 3 drives the polishing table 2 and the polishing pad 1 to rotate around their own axis. The fixing ring 5 is used to fix the wafer. The fixing ring 5 is connected above the polishing pad 1 through the fixing shaft 6, so that the wafer contacts the surface of the polishing pad 1. The wafer is ground and polished by the rotation of the polishing pad 1.

[0061] Reference Figure 1 As shown, the dressing device further includes: a support shaft 7, a second motor 8, a dressing arm 10, a dressing shaft 11, a dressing head 12, a third motor 15, and a pressure device 16. The support shaft 7 is located on one side of the polishing pad 1. The dressing arm 10 is connected to the top of the support shaft 7 and extends above the polishing pad 1. The dressing head 12 is rotatably connected to the lower side of the dressing arm 10 via the dressing shaft 11. The third motor 15 is connected to the dressing shaft 11 and is used to drive the dressing shaft 11 and the dressing head 12 to rotate. The second motor 8 is connected to the support shaft 7 and is used to drive the support shaft 7 and the support arm to swing, causing the dressing head 12 to reciprocate in the radial direction of the polishing pad 1. The dressing shaft 11 can slide vertically on the polishing pad 1. The pressure device 16 is connected to the top of the dressing shaft 11. The pressure device 16 provides downward pressure to the dressing shaft 11 and the dressing head 12, so that the dressing head 12 contacts the surface of the polishing pad 1. The polishing pad 1 is frictionally dressed by the relative rotation of the dressing head 12 and the polishing pad 1.

[0062] In the prior art, the dressing head 12 dresses the surface of the polishing pad 1 by having the operator set the pressure of the dressing head 12 at different positions on the polishing pad 1 based on experience, in order to reduce the unevenness of the wear on the surface of the polishing pad 1. However, the process of changing the pressure has a certain delay, while the oscillation speed of the dressing head 12 is relatively fast. Therefore, eliminating unevenness by changing the pressure is not very effective.

[0063] To solve the above problems, refer to Figure 2 As shown, the trimming method provided in this embodiment includes the following steps:

[0064] Step S1: Obtain the wear amount at each position of polishing pad 1.

[0065] Here, each position of polishing pad 1 refers to any point on the surface of polishing pad 1 used for grinding the wafer, and the loss amount refers to the difference between the initial thickness value of polishing pad 1 and the thickness of polishing pad 1 after grinding the wafer. By obtaining the loss amount at each position of polishing pad 1, the surface loss distribution of polishing pad 1 at any time can be obtained. Furthermore, in practical applications, a surface loss distribution map of polishing pad 1 at any time can be generated based on this surface loss distribution according to requirements, so that relevant personnel can view it.

[0066] Step S2: Divide the surface of polishing pad 1 into multiple trimming areas, and select one of the trimming areas as the reference trimming area.

[0067] The trimming area is divided based on the radius of the trimming head 12, and any one of the trimming areas can be selected as the reference trimming area.

[0068] Reference Figure 3 In this embodiment, the trimming area is divided into multiple trimming areas along the radial direction of the polishing pad 1, starting from the center and moving towards its edge. Specifically, the trimming area at the center is circular, while the remaining trimming areas are annular. The width of each trimming area is half the radius of the trimming head 12. As the trimming head 12 oscillates radially along the polishing pad 1, it passes through each trimming area sequentially. Furthermore, the trimming head 12 can cover at least two adjacent trimming areas, resulting in a smooth transition at the boundary between adjacent trimming areas.

[0069] Step S3: Calculate the first average loss amount in each trimming area based on the loss amount.

[0070] In this embodiment, based on the surface loss distribution map of the polishing pad 1 obtained in real time in step S1, the measured points and their corresponding loss values ​​located in the same trimming area are added together and divided by the number of measured loss location points to obtain the first average loss in each trimming area.

[0071] Step S4: Based on the correspondence between the first average loss of each trimming zone and the reference trimming zone, adjust the rotational speed of the trimming head 12 in each trimming zone.

[0072] The trimming area where the trimming head 12 is located refers to the trimming area where the projection point of the axis of the trimming head 12 on the polishing pad 1 is located.

[0073] The dressing head 12 maintains constant pressure on the polishing pad 1, and the dressing time for each dressing area is consistent. The thickness of the polishing pad 1 removed by the dressing head 12 varies at different rotation speeds. The faster the rotation speed of the dressing head 12, the greater the thickness of the polishing pad 1 removed; conversely, the slower the rotation speed of the dressing head 12, the smaller the thickness of the polishing pad 1 removed. Therefore, by controlling the rotation speed of the dressing head 12 to increase in areas with lower average wear and decrease in areas with higher wear, the surface unevenness of the polishing pad 1 can be reduced.

[0074] The rotational speed of the dressing head 12 is controlled by the third motor 15. The rotational speed of the dressing head 12 can be set between 0 rpm and 120 rpm. During the dressing process, the rotational speed of the dressing head 12 is usually between 60 rpm and 90 rpm. The rotational acceleration of the dressing head 12 is 1000 rpm / s. If the rotational speed of the dressing head 12 changes by 10 rpm, it only takes 0.01 seconds. Therefore, when the dressing head 12 moves in different dressing areas, the change in rotational speed of the dressing head 12 is relatively sensitive and has the advantage of short delay, which can better reduce the unevenness of the polishing pad 1 surface and achieve a better dressing effect.

[0075] In this embodiment, the process of selecting one of the trimming areas as the reference trimming area includes the following steps:

[0076] Compare the magnitude of the first average loss in each trimmed area;

[0077] The trimming area with the largest or smallest average loss is selected as the reference trimming area.

[0078] As an alternative implementation, the reference trimming area can also be selected as the innermost or outermost trimming area, or selected in other ways. It can be adjusted according to actual needs, and the present invention is not limited thereto.

[0079] In this embodiment, adjusting the rotational speed of the dressing head 12 within each dressing region, based on the correspondence between the first average loss of each dressing region and the reference dressing region, includes the following steps:

[0080] Determine the trimming area where the trimming head 12 is located. If it is located within the reference trimming area, adjust the rotation speed of the trimming head 12 within the reference trimming area to the first reference rotation speed.

[0081] If located in other trimming areas, calculate the first ratio of the first average loss of the trimming area to the first average loss of the reference trimming area, and adjust the rotational speed of the trimming head 12 located in other trimming areas based on the first ratio and the first reference rotational speed.

[0082] For example: combining Figure 2As shown, the trimming area with the largest first average wear value is selected as the reference area. From the center of polishing pad 1 to the outside, the trimming areas are A1, A2, ..., A... N The first average loss in each repair area is W1, W2, ..., W... N Among them, the first average wear value W2 is the largest in trimming area A2. Based on the operator's experience, the rotational speed of trimming head 12 when the first average wear value is W2 is set to ω2, that is, the first reference rotational speed is ω2. The first ratio of the first wear value of the reference trimming area to other trimming areas is W2 / W1 = 1.1, W2 / W3 = 1.15, ..., W2 / W3 = 1.05. Therefore, the rotational speed of trimming head 12 in other trimming areas is ω1 = ω2 * 1.1, ω3 = ω2 * 1.15, ..., ω n =ω2*1.05, thereby increasing or decreasing the rotational speed of the dressing head 12 according to the magnitude of the first average loss in the dressing area.

[0083] Furthermore, the process of obtaining the position of the trimming head 12 includes the following steps:

[0084] A reference coordinate system is established on the surface of polishing pad 1 with the center of polishing pad 1 as the origin;

[0085] Determine the first coordinate value of the support axis 7 of the polishing device in the reference coordinate system;

[0086] Obtain the rotation angle of polishing pad 1, and calculate the real-time coordinate system after the reference coordinate system is rotated;

[0087] The swing angle of the trimming arm 10 of the polishing device is obtained, and the second coordinate value of the trimming head 12 in the real-time coordinate system is obtained based on the distance between the projections of the axis of the support shaft 7 and the axis of the trimming shaft 11 on the surface of the polishing pad 1.

[0088] Based on the second coordinate value, the absolute position of the trimming head 12 on the polishing pad 1 is determined, and the trimming area where the trimming head 12 is located is obtained.

[0089] Specifically, in combination Figure 3 As shown, the center point of the surface of the polishing pad 1 is set as the origin O, and two straight lines that are radially perpendicular to each other along the polishing pad 1 are distributed as the X-axis and Y-axis, thereby forming a plane rectangular coordinate system X-Y, i.e., the reference coordinate system, on the surface of the polishing pad 1.

[0090] The first motor 3 has a first encoder 4. The first encoder 4 can obtain the rotation angle α of the polishing pad 1 compared with the initial state in real time. By the rotation angle α, the real-time coordinate system X-Y after rotation can be obtained from the reference coordinate system X-Y to the real-time coordinate system X1-Y1.

[0091] The first coordinate value of the support shaft 7 in the reference coordinate system refers to the first coordinate value (X-Y) of the projection point P of the axis of the support shaft 7 onto the surface of the polishing pad 1 in the reference coordinate system. p Y p The second motor 8 has a second encoder 9, which can provide feedback on the rotation angle β of the trimming arm 10 at any time. The projection point of the axis of the trimming shaft 11 on the surface of the polishing pad 1 is N, and the rotation angle β is the angle between the line connecting the origin 0 and the projection point P of the support shaft 7 and the line connecting the projection point N of the trimming shaft 11 and the projection point P of the support shaft 7.

[0092] The distance R between projection points N and P is fixed. The coordinates (X, Y, F, Z) of projection point P in the reference coordinate system are determined by the support axis 7. p Y p This allows us to calculate the dynamic coordinates (X, Y) of the projection point N within the reference coordinate system at any given time. N Y N Furthermore, the correspondence between the coordinate values ​​of projection point P and projection point N within the same coordinate system can be obtained. Then, based on the obtained real-time coordinate system X1-Y1, the second coordinate value (X...) of projection point N within the real-time coordinate system X1-Y1 can be calculated. N1 Y N1 ), to determine the absolute position of the trimming head 12 on the polishing pad 1.

[0093] Among them, X N1 =X N cos(-θ)+Y N sin(-θ), Y N1 =-X N sin(-θ)+Y N cos(-θ).

[0094] Finally, based on the second coordinate value (X) of the projection point N of the axis of the dressing head 12 onto the surface of the polishing pad 1, N1 Y N1 Then, based on the size and position of the trimmed area divided in step S2, determine the second coordinate value (X). N1 Y N1 By determining which trimming area the polishing head is located in, we can identify the trimming area.

[0095] Furthermore, the process of obtaining the wear amount at each location of polishing pad 1 includes the following steps:

[0096] The amount of displacement perpendicular to the surface of the polishing pad 1 at each position during the process of trimming the polishing pad 1 by the trimming head 12;

[0097] Based on the displacement, the wear of the trimming head 12 at each position on the polishing pad 1 is calculated.

[0098] By setting a preset pressure value, the dressing head 12 maintains a constant pressure on the polishing pad 1. During its movement, the dressing head 12 moves perpendicular to the surface of the polishing pad 1 due to varying wear levels. The amount of wear on the polishing pad 1 surface compared to its initial state can be calculated from the displacement of the dressing head 12. Combined with the coordinates of the absolute position of the dressing head 12 on the polishing pad 1, the wear level of the dressing head 12 at each position on the polishing pad 1 is recorded in real time during the dressing process. The wear distribution map on the surface of the polishing pad 1 also changes in real time. The rotational speed of the dressing head 12 when it passes the same dressing area again will change according to the real-time wear changes on the surface of the polishing pad 1, thereby better eliminating the unevenness of the polishing pad 1 surface.

[0099] In this embodiment, refer to Figure 1 A sensor 13 is provided on the trimming shaft 11. The sensor 13 obtains the displacement of the trimming head 12 by monitoring the distance between itself and the trimming arm 10.

[0100] For example, when the polishing pad 1 is not worn, the dressing head 12 acts on the surface of the polishing pad 1 with a preset pressure value, and the distance between the sensor 13 and the dressing arm 10 is L0. After the polishing pad 1 is worn, when the dressing head 12 acts on the surface of the polishing pad 1 with the same preset pressure, the sensor 13 moves downward with the dressing shaft 11. At this time, the distance between the sensor 13 and the dressing arm 10 is L1. Then, the wear amount of the polishing pad 1 at the current position is W = L1 - L0.

[0101] During the polishing process of the polishing pad 1, there may be abnormal protrusions or depressions on the surface of the polishing pad 1. The wear of these abnormal parts is significantly different from that of other parts, which will affect the first average wear value of the trimmed area. Moreover, when the trimming head 12 trims the abnormal parts with the rotation speed corresponding to the first average wear value of the trimmed area, it cannot effectively eliminate the inhomogeneity of the abnormal parts.

[0102] To address the issue of abnormal areas on the surface of polishing pad 1, the trimming method in this embodiment further includes the following steps:

[0103] Determine whether trimming head 12 has moved to an abnormal area;

[0104] When the dressing head 12 moves to the abnormal area, the rotational speed of the dressing head 12 is adjusted based on the second average loss amount of the abnormal area.

[0105] The abnormal area refers to the location within the trimming area where the loss value is abnormal. The process of determining the abnormal area includes:

[0106] Multiple detection areas are divided within the same trimming area;

[0107] Calculate the second average loss for each of the detection regions;

[0108] Determine whether the second average loss within the same trimming area exceeds a preset abnormal threshold; if the second average loss exceeds the preset abnormal threshold, set the detection area corresponding to the second average loss as an abnormal area.

[0109] Specifically, refer to Figure 4 The detection area is divided along the circumference of the polishing pad 1, that is, the annular trimming area is divided into multiple fan-shaped detection areas. The number of detection areas is determined according to the diameter of the polishing pad 1, and the size of each detection area can be the same or different.

[0110] Similar to the method for obtaining the first average loss amount in each trimming area in step S3 above, the second average loss amount in each detection area is calculated. Based on the magnitude of the second average loss amount of each detection area within the same trimming area, if the second average loss amount of a certain detection area is too large or too small, it indicates that there is an abnormal part in the detection area, and therefore the detection area can be set as an abnormal area.

[0111] Furthermore, the step of determining whether the second average loss exceeds the abnormal threshold includes the following steps:

[0112] Calculate the absolute value of the difference between the second average loss of the detection area and the first average loss of the trimming area where the detection area is located.

[0113] Calculate the second ratio of the absolute value to the first average loss;

[0114] Determine whether the second ratio exceeds the abnormal threshold.

[0115] For example: combining Figure 4 As shown, in the trimming region A2, the first average loss is W2, and the anomaly threshold is set to 20%. The annular trimming region A2 is divided into twelve identical fan-shaped detection regions, each named A in a clockwise direction. 21 A 22 ... A 212 The average loss corresponding to each detection area is W, in order. 21 W 22 ... W 212 .

[0116] If for detection area A 22 |W2-W 22 If | / W2>20%, then the detection area A 22 The second average loss exceeded the preset abnormal threshold, and the detection area A...22 This is an abnormal region.

[0117] Furthermore, the process of adjusting the rotational speed of the dressing head 12 based on the second average loss in the abnormal region includes the following steps:

[0118] The rotational speed of the trimming head 12 in the trimming area where the abnormal area is located is taken as the second reference rotational speed;

[0119] When the trimming head 12 moves into the abnormal area, the rotational speed of the trimming head 12 is adjusted to the second reference rotational speed multiplied by the second ratio.

[0120] For example, the second reference rotational speed of the dressing head 12 within the dressing region A2 is ω2. When the dressing head 12 enters the abnormal region A... 22 During this time, adjust the rotation speed of the dressing head 12 to ω2*(W2 / W). 22 This allows the trimming head 12 to trim abnormal areas accordingly.

[0121] This embodiment also provides a polishing apparatus, see reference. Figure 1 The polishing apparatus includes a monitoring device 14. The first encoder 4, the second encoder 9, and the sensor 13 described in any of the above embodiments are all communicatively connected to the monitoring device 14. The monitoring device 14 can acquire the rotation angle of the polishing pad 1, the swing angle of the trimming arm 10 acquired by the second encoder 9, and the surface wear of the polishing pad 1 monitored by the sensor 13 at any given time. The monitoring device 14 is also communicatively connected to a third motor 15. The monitoring device 14 controls the rotation speed of the third motor 15 by executing the trimming method described in any of the above embodiments, causing the trimming head 12 to trim the corresponding trimming area at the corresponding rotation speed. This polishing apparatus trims the polishing pad using the trimming method described in any of the above embodiments to better eliminate the unevenness of the polishing pad 1 surface.

[0122] This embodiment also provides a chemical mechanical polishing apparatus, which includes the polishing device described above. The polishing device is used to grind and polish the wafer. The dressing head 12 adjusts the rotation speed by means of the dressing method described in any of the above embodiments to reduce the unevenness of the surface of the polishing pad 1, so that the polishing pad 1 can better grind and polish the wafer and improve the finished quality of the wafer.

[0123] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method of conditioning a polishing apparatus, the polishing apparatus comprising a polishing pad and a conditioning apparatus, the conditioning apparatus having a conditioning head configured to correspond to the polishing pad, the method comprising: rotating the conditioning head at a first rotational speed; and rotating the conditioning head at a second rotational speed different from the first rotational speed. The method comprises the following steps: obtaining the loss amount of each position of the polishing pad; the obtaining of the loss amount of each position of the polishing pad specifically comprises: obtaining the displacement amount in the direction perpendicular to the surface of the polishing pad during the process of the trimming head trimming the polishing pad at each position; and calculating the loss amount of the trimming head at each position of the polishing pad based on the displacement amount; dividing the surface of the polishing pad into multiple trimming regions based on the diameter of the trimming head, and selecting one of the trimming regions as a reference trimming region; calculating the first average loss amount in each trimming region based on the loss amount; adjusting the rotating speed of the trimming head in each trimming region based on the corresponding relationship between the first average loss amount of each trimming region and the reference trimming region; wherein the adjusting of the rotating speed of the trimming head in each trimming region based on the corresponding relationship between the first average loss amount of each trimming region and the reference trimming region comprises: judging the trimming region where the trimming head is located, if the trimming head is located in the reference trimming region, adjusting the rotating speed of the trimming head in the reference trimming region to a first reference rotating speed, if the trimming head is located in other trimming regions, calculating the first ratio of the first average loss amount of the trimming region to the first average loss amount of the reference trimming region, and adjusting the rotating speed of the trimming head in other trimming regions based on the first ratio and the first reference rotating speed; the trimming method further comprises: judging whether the trimming head moves to an abnormal region; when the trimming head moves to the abnormal region, adjusting the rotating speed of the trimming head based on the second average loss amount of the abnormal region; wherein the process of determining the abnormal region comprises: dividing multiple detection regions in the same trimming region; calculating the second average loss amount of each detection region; judging whether the second average loss amount located in the same trimming region exceeds a preset abnormal threshold; if the second average loss amount exceeds the preset abnormal threshold, setting the detection region corresponding to the second average loss amount as an abnormal region.

2. The polishing apparatus dressing method according to claim 1, wherein the judging of the trimming region where the trimming head is located comprises: establishing a reference coordinate system on the surface of the polishing pad with the center of the polishing pad as the origin; calculating the first coordinate value of the support shaft of the trimming device in the reference coordinate system; obtaining the rotating angle of the polishing pad, and calculating the real-time coordinate system after the rotation of the reference coordinate system; obtaining the swing angle of the trimming arm of the polishing device, and calculating the second coordinate value of the trimming head in the real-time coordinate system based on the distance between the support shaft and the axis of the trimming head; based on the second coordinate value, determining the absolute position of the trimming head on the polishing pad, and obtaining the trimming region where the trimming head is located.

3. The polishing apparatus dressing method according to Claim 1, wherein the selecting of one of the trimming regions as the reference trimming region comprises: comparing the first average loss amount of each trimming region; selecting the trimming region with the maximum or minimum first average loss amount as the reference trimming region.

4. The polishing apparatus dressing method according to Claim 1, wherein the judging of whether the second average loss amount exceeds the preset abnormal threshold comprises: obtaining an absolute value of a difference between a second average loss amount of the detection area and a first average loss amount of a dressing area where the detection area is located; obtaining a second ratio of the absolute value to the first average loss amount; determining whether the second ratio exceeds the abnormality threshold value.

5. The polishing apparatus dressing method according to Claim 4, wherein the adjusting the rotation speed of the dressing head based on the second average loss amount of the abnormal area includes: taking a rotation speed of the dressing head in a dressing area where the abnormal area is located as a second reference rotation speed; obtaining a third ratio of a first average loss amount of the dressing area where the abnormal area is located to the second average loss amount of the abnormal area; adjusting the rotation speed of the dressing head based on the second reference rotation speed and the third ratio when the dressing head moves into the abnormal area.

6. A polishing apparatus characterized by comprising: The polishing apparatus is dressed using the polishing apparatus dressing method according to any one of claims 1 to 5.

7. A chemical mechanical polishing apparatus characterized by comprising: The polishing apparatus includes the polishing apparatus according to claim 6.

Images