Pressure adjustment method, device, electronic device, storage medium and program product

Abstract

The embodiments of the present application relate to the field of wafer polishing technology, and in particular to a pressure adjustment method, device, electronic device, storage medium and program product, wherein the pressure adjustment method comprises: obtaining a mapping relationship between a groove depth of a retaining ring included in a polishing device and a signal output by an eddy current sensor when the polishing device is working, the retaining ring comprises an annular metal part inside the retaining ring, the eddy current sensor and the retaining ring are located on both sides of a polishing pad included in the polishing device, and during the chemical mechanical polishing of the wafer by the polishing device, the metal part is opposite to the eddy current sensor in a direction perpendicular to the polishing pad at least part of the time; during the chemical mechanical polishing of the wafer by the polishing device, the output signal of the eddy current sensor is obtained; according to the mapping relationship and the output signal, the current groove depth of the retaining ring is determined to adjust the pressure between the edge of the wafer and the polishing pad. This solution optimizes the effect of chemical mechanical polishing of the edge of the wafer.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of wafer polishing technology, and in particular to a pressure adjustment method, device, electronic device, storage medium and program product. Background Art

[0002] During the integrated circuit manufacturing process, the wafer surface is flattened through chemical mechanical polishing (CMP), which can be achieved through polishing equipment.

[0003] like Figure 1 and Figure 2 As shown, the polishing equipment includes a carrier head 1, a retaining ring 2 and a polishing pad 3. The carrier head 1 and the retaining ring 2 are both located above the polishing pad 3, and the retaining ring 2 is located below the carrier head 1. One annular surface of the retaining ring 2 is connected to the carrier head 1, and a groove 21 is provided on the other annular surface of the retaining ring 2. The lower end of the carrier head 1 is connected to a pressing member 4, and the retaining ring 2 is arranged outside the pressing member 4. During the use of the polishing equipment, the wafer is first placed in the space surrounded by the retaining ring 2, and the retaining ring 2 is adjusted to abut against the polishing pad 3. At this time, the wafer abuts between the pressing member 4 and the polishing pad 3, and then the pressing member 4 is controlled to provide downward pressure so that the pressure between the wafer and the polishing pad 3 is appropriate. Then the carrier head 1 and the polishing pad 3 are controlled to move relative to each other so that the wafer and the retaining ring 2 move along the upper surface of the polishing pad 3. At the same time, the polishing liquid sprayed on the polishing pad 3 can fully contact the wafer in the retaining ring 2 through the groove 21 of the retaining ring 2, thereby realizing chemical mechanical polishing of the wafer.

[0004] However, after the polishing equipment has been used for a period of time, the retaining ring 2 will be worn more, so that the depth of the groove 21 of the retaining ring 2 will become smaller, and then the pressure between the retaining ring 2 and the polishing pad 3 will become smaller, and the pressure between the edge of the wafer and the polishing pad 3 will also decrease accordingly. In response to this situation, some operators will increase the pressure of the down-pressing member 4 on the edge of the wafer during the polishing process at regular intervals. However, due to the irregular polishing frequency and non-unique polishing conditions, the wear of the retaining ring 2 does not change regularly with the increase in polishing time. As a result, when the pressure of the down-pressing member 4 on the edge of the wafer is increased during the polishing process, it is impossible to determine a reasonable pressure adjustment amount, which can easily cause the pressure between the edge of the wafer and the polishing pad 3 to be too high or too low during the polishing process. Therefore, the effect of chemical mechanical polishing of the edge of the wafer is poor. Summary of the invention

[0005] In view of this, embodiments of the present application provide a pressure adjustment method, device, electronic device, storage medium and program product to at least partially solve the above problems.

[0006] According to a first aspect of an embodiment of the present application, a pressure adjustment method is provided, comprising: obtaining a mapping relationship between a groove depth of a retaining ring included in a polishing device and a signal output by an eddy current sensor when the polishing device is working, wherein the polishing device is used to perform chemical mechanical polishing on a wafer and comprises a polishing pad, the retaining ring comprises an annular metal portion located inside the retaining ring, the groove of the retaining ring is opened on a side of the retaining ring close to the polishing pad, the eddy current sensor and the retaining ring are located on both sides of the polishing pad, and during chemical mechanical polishing of the wafer by the polishing device, the metal portion in the retaining ring is opposite to the eddy current sensor at least part of the time in a direction perpendicular to the polishing pad; during chemical mechanical polishing of the wafer by the polishing device, obtaining an output signal of the eddy current sensor; determining a current groove depth of the retaining ring based on the mapping relationship and the output signal; and adjusting the pressure between the edge of the wafer and the polishing pad based on the current groove depth.

[0007] According to a second aspect of an embodiment of the present application, a pressure adjustment device is provided, comprising: a relationship acquisition unit, for acquiring a mapping relationship between a groove depth of a retaining ring included in a polishing device and a signal output by an eddy current sensor when the polishing device is working, wherein the polishing device is used to perform chemical mechanical polishing on a wafer and comprises a polishing pad, the retaining ring comprises an annular metal portion located inside the retaining ring, the groove of the retaining ring is opened on a side of the retaining ring close to the polishing pad, the eddy current sensor and the retaining ring are located on both sides of the polishing pad, and during the process of chemical mechanical polishing of the wafer by the polishing device, the metal portion in the retaining ring is opposite to the eddy current sensor at least part of the time in a direction perpendicular to the polishing pad; a signal acquisition unit, for acquiring an output signal of the eddy current sensor during the process of chemical mechanical polishing of the wafer by the polishing device; a depth determination unit, for determining a current groove depth of the retaining ring according to the mapping relationship and the output signal; and a pressure adjustment unit, for adjusting the pressure between the edge of the wafer and the polishing pad according to the current groove depth.

[0008] According to the third aspect of an embodiment of the present application, there is provided an electronic device comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; the memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the method of the first aspect described above.

[0009] According to a fourth aspect of an embodiment of the present application, a computer storage medium is provided, on which a computer program is stored, and the program is executed by a processor to perform the method of the first aspect.

[0010] According to a fifth aspect of an embodiment of the present application, a computer program product is provided, comprising computer instructions, wherein the computer instructions instruct a computing device to execute the method of the first aspect described above.

[0011] According to the pressure adjustment scheme provided in the embodiment of the present application, the mapping relationship between the groove depth of the retaining ring and the signal output by the eddy current sensor when the polishing device is working can be obtained, and the output signal of the eddy current sensor is obtained during the chemical mechanical polishing process, and then the current groove depth of the retaining ring is determined according to the obtained mapping relationship and the above output signal, and then the pressure between the edge of the wafer and the polishing pad is adjusted according to the current groove depth. Therefore, after the polishing device is used for a period of time, even if the groove depth of the retaining ring decreases due to wear and other reasons, the current groove depth of the retaining ring can be detected, and the pressure between the edge of the wafer and the polishing pad can be adjusted according to the current groove depth. Compared with the related art that adjusts the pressure between the edge of the wafer polished by the polishing device and the polishing pad at regular intervals, the present application adjusts the pressure according to the specific value of the current groove depth, and then the adjustment timing and adjustment amount of the pressure adjustment are more accurate, which can reduce the possibility of excessive or insufficient pressure between the edge of the wafer and the polishing pad during the polishing process, thereby optimizing the effect of chemical mechanical polishing of the edge of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0013] Figure 1 is a cross-sectional view of a polishing device in the background art;

[0014] Figure 2 It is a structural diagram of the retaining ring;

[0015] Figure 3 is a cross-sectional view of a polishing device according to an embodiment of the present application;

[0016] Figure 4 is a flow chart of a pressure adjustment method according to an embodiment of the present application;

[0017] Figure 5 is a schematic diagram of signal values ​​corresponding to the same target retention ring in one embodiment of the present application;

[0018] Figure 6 is a schematic diagram of signal values ​​corresponding to different target retention rings according to an embodiment of the present application;

[0019] Figure 7 is a schematic diagram of a pressure adjustment device according to an embodiment of the present application;

[0020] Figure 8 It is a schematic block diagram of an electronic device according to an embodiment of the present application.

[0021] Description of reference numerals:

[0022] 1. Carrying head; 2. Retaining ring; 21. Groove; 3. Polishing pad; 31. Polishing surface; 4. Pressing piece; 5. Polishing disk; 51. Eddy current sensor. DETAILED DESCRIPTION

[0023] The embodiment of the present application proposes a pressure adjustment scheme. The entire pressure adjustment scheme can be used to adjust the pressure between the edge of the wafer and the polishing pad during the chemical mechanical polishing process of the wafer. The pressure adjustment scheme can be executed by a data center, a server, a personal computer, an Internet of Things (IoT) device, an embedded device, etc. The pressure adjustment scheme is independent of the hardware deployed by the computing device executing the scheme.

[0024] An embodiment of the present application provides a pressure adjustment method, by which the pressure between the edge of the wafer and the polishing pad can be adjusted during chemical mechanical polishing of a wafer by a polishing device.

[0025] Figure 3 is a cross-sectional view of a polishing device according to an embodiment of the present application. Figure 3 As shown, the polishing device includes a carrier head 1, a retaining ring 2, a polishing pad 3 and a polishing plate 5. The structure of the retaining ring 2 is as shown in FIG. Figure 2As shown, the retaining ring 2 includes a metal part located inside the retaining ring 2, the retaining ring 2 and the metal part are both in annular shape, and the axis of the retaining ring 2 as a whole coincides with the axis of the metal part, the carrier head 1 and the retaining ring 2 are both located above the polishing pad 3, and the retaining ring 2 is located below the carrier head 1. The carrier head 1 presses the wafer onto the polishing pad 3 covered on the surface of the polishing disk 5, and the carrier head 1 performs a rotational motion and reciprocates along the radial direction of the polishing disk 5 so that the surface of the wafer in contact with the polishing pad 3 is gradually polished away. One annular surface of the retaining ring 2 is detachably fixedly connected to the lower end of the carrier head 1, and a plurality of grooves 21 are provided on the other annular surface of the retaining ring 2. The plurality of grooves 21 are distributed along the circumference of the retaining ring 2, and the grooves 21 penetrate from the inner side surface of the retaining ring 2 to the outer side surface of the retaining ring 2; a lower end of the carrier head 1 is also connected to a pressing piece 4, and the retaining ring 2 is arranged outside the pressing piece 4, and the pressing piece 4 can be an air film or the like; the material of the polishing pad 3 is not a metal conductor, and the polishing pad 3 is located above the polishing disk 5, and the polishing pad 3 is fixedly connected to the polishing disk 5 or detachably fixed The polishing surface 31 (that is, the upper surface of the polishing pad 3 in the polishing equipment) of the outer surface of the polishing pad 3 for polishing the wafer is circular, and the diameter of the retaining ring 2 is smaller than the diameter of the polishing surface 31; an eddy current sensor 51 is installed in the polishing disk 5, so that the eddy current sensor 51 and the retaining ring 2 are located on both sides of the polishing pad 3, the eddy current sensor 51 is in contact with the lower side of the polishing pad 3, and the signal output by the eddy current sensor 51 is an eddy current signal, such as a voltage signal or a current signal, etc., which is not limited to the embodiments of the present application.

[0026] During the chemical mechanical polishing process of the polishing equipment, the wafer is first set in the space enclosed by the retaining ring 2, and the retaining ring 2 is adjusted to abut against the polishing surface 31. At this time, the wafer abuts between the lower pressure piece 4 and the polishing pad 3, and then the lower pressure piece 4 is controlled to provide downward pressure so that the pressure between the wafer and the polishing pad 3 is appropriate. Then the carrier head 1 and the polishing pad 3 are controlled to move relative to each other so that the wafer and the retaining ring 2 move along the polishing surface 31 of the polishing pad 3. For example, the carrier head 1 can be controlled to drive the retaining ring 2 and the wafer to rotate around the axis of the retaining ring 2, and the carrier head 1 can be controlled to drive the retaining ring 2 and the wafer to reciprocate along any radius of the polishing surface 31. The polishing disk 5 can also be controlled to drive the polishing pad 3 to rotate around the axis of the polishing surface 31. At the same time, the polishing equipment sprays polishing liquid onto the polishing surface 31 of the polishing pad 3. The polishing liquid can fully contact the wafer in the retaining ring 2 through the groove 21 of the retaining ring 2, thereby realizing chemical mechanical polishing of the wafer.

[0027] During the chemical mechanical polishing process of the wafer by the polishing equipment, the metal part in the ring 2 is kept opposite to the eddy current sensor 51 at least part of the time in the direction perpendicular to the polishing pad 3; when the metal part on the ring 2 and the space enclosed by the metal part are not opposite to the eddy current sensor 51 in the direction perpendicular to the polishing pad 3, that is, the metal part on the ring 2 is not on the straight line passing through the eddy current sensor 51 and perpendicular to the polishing surface 31, and the space enclosed by the metal part in the ring 2 is not on the straight line, the eddy current signal output by the eddy current sensor 51 is small; when the metal part in the ring 2 is kept opposite to the eddy current sensor 51 in the direction perpendicular to the polishing pad 3, that is, the metal part in the ring 2 is on the above-mentioned straight line, the metal part cuts the magnetic field of the eddy current sensor 51, so that the eddy current signal output by the eddy current sensor 51 becomes larger.

[0028] Based on this, the above pressure adjustment method is described in detail below through multiple embodiments.

[0029] Figure 4 FIG. 1 is a flow chart of a pressure adjustment method according to an embodiment of the present application. Figure 4 As shown, the pressure adjustment method includes the following steps:

[0030] Step 401 : Obtain a mapping relationship between a groove depth of a retaining ring 2 included in a polishing device and a signal output by an eddy current sensor 51 when the polishing device is working.

[0031] In a specific embodiment, the mapping relationship can be a mapping relationship between the groove depth of the retaining ring 2 and the maximum signal value output by the eddy current sensor 51 when the polishing equipment is working. For example, the mapping relationship can be the groove depth H=F(B), and the function F(B) is a linear function, a quadratic function or other functional formula, such as H=A*B, where A is the proportionality coefficient, and B is the maximum signal value output by the eddy current sensor 51 when the polishing equipment is working. Multiple sets of corresponding specific values ​​of H and B can be determined in advance by experiments, so as to determine A by fitting or the like.

[0032] Step 402 : Acquire the output signal of the eddy current sensor 51 during the process of chemical mechanical polishing of the wafer by the polishing equipment.

[0033] Step 403: Determine the current groove depth of the retaining ring 2 according to the above mapping relationship and the above output signal.

[0034] In a specific embodiment, during the chemical mechanical polishing of a wafer by a polishing device, when the polishing pad 3 rotates at least one circle around the axis of the polishing surface 31 driven by the polishing disk 5, the current groove depth of the retaining ring 2 is determined based on the above mapping relationship and the above output signal.

[0035] For example, based on the above example of H=A*B, during the chemical mechanical polishing of the wafer by the polishing equipment, the polishing pad 3 rotates around the axis of the polishing surface 31 one circle driven by the polishing disk 5. It can be determined that during the rotation of the polishing pad 3 one circle, the maximum signal value B of the output signal of the eddy current sensor 51 is b, and B=b is substituted into H=A*B to obtain the current groove depth H as A*b.

[0036] Step 404: Adjust the pressure between the edge of the wafer and the polishing pad 3 according to the current groove depth.

[0037] In a specific embodiment, if the current groove depth changes relative to the initial groove depth of the retaining ring 2 , the downward pressure of the pressing member 4 on the edge of the wafer is adjusted to adjust the pressure between the edge of the wafer and the polishing pad 3 .

[0038] In the embodiment of the present application, the mapping relationship between the groove depth of the retaining ring 2 and the signal output by the eddy current sensor 51 when the polishing device is working can be obtained, and the output signal of the eddy current sensor 51 is obtained during the chemical mechanical polishing process, and then the current groove depth of the retaining ring 2 is determined according to the obtained mapping relationship and the above output signal, and then the pressure between the edge of the wafer and the polishing pad 3 is adjusted according to the current groove depth. Therefore, after the polishing device is used for a period of time, even if the groove depth of the retaining ring 2 decreases due to wear and other reasons, the current groove depth of the retaining ring 2 can be detected, and the pressure between the edge of the wafer and the polishing pad 3 can be adjusted according to the current groove depth. Compared with the related art that adjusts the pressure between the edge of the wafer polished by the polishing device and the polishing pad 3 at regular intervals, the present application adjusts the pressure according to the specific value of the current groove depth, and then the adjustment timing and adjustment amount of the pressure adjustment are more accurate, which can reduce the possibility of excessive or insufficient pressure between the edge of the wafer and the polishing pad 3 during the polishing process, thereby optimizing the effect of chemical mechanical polishing of the edge of the wafer.

[0039] In addition, in the embodiment of the present application, since the current groove depth of the retaining ring 2 is determined by the mapping relationship and the output signal of the eddy current sensor 51 during the chemical mechanical polishing process, there is no need to remove the retaining ring 2 and physically measure the groove depth. Therefore, the chemical mechanical polishing of the wafer is faster and more convenient. Moreover, since the current groove depth of the retaining ring 2 can be continuously detected during the chemical mechanical polishing process, compared with the solution of measuring the initial groove depth of the retaining ring 2 and then estimating the current groove depth of the retaining ring 2 based on the initial groove depth and the polishing time, in the present application, even if the polishing environment is more complex and the groove depth of the retaining ring 2 does not change regularly, the error of the current groove depth of the retaining ring 2 relative to the actual groove depth is also smaller.

[0040] In a possible implementation, in the process of obtaining the output signal of the eddy current sensor 51 in the above step 402, the first output signal of the eddy current sensor 51 is obtained when the polishing device is working in the first state, and the second output signal of the eddy current sensor 51 is obtained when the polishing device is working in the second state.

[0041] Among them, the first state is a state in which the metal part in the ring 2 is opposite to the eddy current sensor 51 in the direction perpendicular to the polishing pad 3, that is, the metal part in the ring 2 is located directly above the eddy current sensor 51; the second state is a state in which the metal part in the ring 2 and the space enclosed by the metal part are not opposite to the eddy current sensor 51 in the direction perpendicular to the polishing pad 3, that is, the metal part in the ring 2 is not located above the eddy current sensor 51, and the space enclosed by the metal part is not located above the eddy current sensor 51.

[0042] Based on this, the above step 403 may include the following specific processing: determining the current groove depth of the retaining ring 2 according to the mapping relationship, the first output signal and the second output signal.

[0043] Correspondingly, the mapping relationship is a mapping relationship between the groove depth of the retaining ring 2, the signal output by the eddy current sensor 51 during the polishing device working in the first state, and the signal output by the eddy current sensor 51 during the polishing device working in the second state, based on this:

[0044] In a specific embodiment, during the chemical mechanical polishing of a wafer by a polishing device, the first output signal and the second output signal of the eddy current sensor 51 can be obtained to utilize the mapping relationship to determine the current groove depth of the retaining ring 2 according to the first output signal and the second output signal.

[0045] In the embodiment of the present application, the current groove depth of the retaining ring 2 can be determined based on the first output signal and the second output signal, wherein the first output signal is the output signal of the eddy current sensor 51 when the metal part in the retaining ring 2 is opposite to the eddy current sensor 51 in the direction perpendicular to the polishing pad 3, and the second signal is the output signal of the eddy current sensor 51 when the metal part in the retaining ring 2 and the space enclosed by the metal part are not opposite to the eddy current sensor 51 in the direction perpendicular to the polishing pad 3. Therefore, the detection of the current groove depth of the retaining ring 2 not only takes into account the situation when the output signal of the eddy current sensor 51 is affected by the retaining ring 2, but also takes into account the situation when the output signal of the eddy current sensor 51 is not affected by the retaining ring 2, and further takes into account the interference of other factors other than the retaining ring 2 on the output signal of the eddy current sensor 51, so that the accuracy of detecting the current groove depth of the retaining ring 2 can be improved.

[0046] Before the above step 401, the mapping relationship must be determined first, which can be specifically as follows:

[0047] In one possible implementation, the pressure adjustment method also includes: obtaining the groove depths of multiple target retaining rings with different groove depths; after the target retaining ring is installed in the polishing equipment, controlling the polishing equipment to operate so that the polishing pad 3 in the polishing equipment rotates at least one circle, and when the polishing equipment is operating in the first state, obtaining multiple first signal values ​​output by the eddy current sensor 51 at different times; when the polishing equipment is operating in the second state, obtaining multiple second signal values ​​output by the eddy current sensor 51 at different times; determining the mapping relationship based on the multiple first signal values ​​and the multiple second signal values ​​obtained after each target retaining ring is installed in the polishing equipment, and the groove depth of each target retaining ring.

[0048] The method for obtaining multiple target retaining rings with different groove depths may include preparing multiple retaining rings 2 with different groove depths, and using the multiple retaining rings 2 as target retaining rings; it may also include preparing multiple retaining rings 2 with different groove depths, and then changing the groove depth of the retaining ring 2 by polishing for a certain period of time to cause the retaining ring 2 to wear. For each retaining ring 2, the retaining ring 2 before wear and the retaining ring 2 after wear are respectively determined as target retaining rings to obtain multiple target retaining rings. The same retaining ring 2 can also be worn once or multiple times so that two or more target retaining rings can be obtained based on a prepared retaining ring 2, thereby expanding the number of target retaining rings and making the mapping relationship more accurate. The method of wearing the retaining ring 2 may be manual polishing or installing the retaining ring 2 in a polishing device for chemical mechanical polishing, etc., and the embodiments of the present application are not limited to this.

[0049] In a specific embodiment, for each target retaining ring, after the target retaining ring is obtained, the groove depth of the target retaining ring can be measured by physical means, and then the target retaining ring is installed in the polishing equipment, and then the polishing equipment is controlled to operate so that the polishing pad 3 in the polishing equipment rotates at least one circle, and when the polishing equipment is working in the first state, multiple first signal values ​​output by the eddy current sensor 51 at different times are obtained, and when the polishing equipment is working in the second state, multiple second signal values ​​output by the eddy current sensor 51 at different times are obtained. Finally, the mapping relationship can be determined based on the multiple first signal values ​​and multiple second signal values ​​obtained after each target retaining ring is installed in the polishing equipment, and the groove depth of each target retaining ring.

[0050] It should be noted that, in the process of controlling the operation of the polishing equipment after the target retaining ring is installed in the polishing equipment, the polishing equipment can be controlled to operate in a state with or without a wafer installed. The embodiments of the present application do not limit this. Operating in a state with a wafer installed means performing chemical mechanical polishing on the wafer, and operating in a state with no wafer installed means that the wafer is not installed in the polishing equipment, but each part of the polishing equipment operates in a manner of performing chemical mechanical polishing on the wafer. Operating in a state with no wafer installed can facilitate the acquisition of mapping relationships and reduce the rejection rate of wafers after chemical mechanical polishing.

[0051] For example, for a target retaining ring, the groove depth of the target retaining ring can be measured, and then the retaining ring 2 in the polishing device is replaced with the target retaining ring, and then the polishing device is controlled to work in a state where no wafer is installed until the polishing pad 3 in the polishing device rotates one circle. During the operation of the polishing device, the signal value output by the eddy current sensor 51 is obtained multiple times, and the result of obtaining the signal value is as follows: Figure 5 As shown, Figure 5 The ordinate is the signal value output by the eddy current sensor 51, and the abscissa is the working time of the polishing device. Figure 5 Some of the multiple signal values ​​output by the eddy current sensor 51 are first signal values, and another part of the signal values ​​are second signal values. In addition, Figure 5 The signal value other than the first signal value and the second signal value among the multiple signal values ​​output by the eddy current sensor 51 is the third signal value. The third signal value is the signal value output by the eddy current sensor 51 when the polishing equipment is working in the third state. The third state is a state in which the space enclosed by the metal part in the ring 2 is opposite to the eddy current sensor 51 in a direction perpendicular to the polishing pad 3, that is, the space enclosed by the metal part in the ring 2 is located directly above the eddy current sensor 51.

[0052] In addition, since the groove depths of different target retaining rings are different, after different target retaining rings are installed in the polishing equipment, the maximum first signal value output by the eddy current sensor 51 during the process of controlling the polishing equipment to work in a state where no wafer is installed is also different. For example, Figure 6 This is a schematic diagram of signal values ​​corresponding to different target retention rings according to an embodiment of the present application, such as Figure 6 As shown, the ordinate is the signal value output by the eddy current sensor 51, and the abscissa is the working time of the polishing device. Figure 6 The signal value indicated by the triangular point in is the signal value output by the eddy current sensor 51 during the process of controlling the polishing device to work in a state where no wafer is installed after the first target holding ring is installed on the polishing device. Figure 6The signal value indicated by the circular point in is the signal value output by the eddy current sensor 51 during the process of controlling the polishing device to work in a state where no wafer is installed after the second target holding ring is installed in the polishing device. Figure 6 The signal value indicated by the cross point in the figure is the signal value output by the eddy current sensor 51 during the process of controlling the polishing device to work in a state where no wafer is installed after the third target holding ring is installed on the polishing device. Figure 6 It can be seen that the maximum first signal values ​​corresponding to different target holding rings are different.

[0053] In one possible implementation, in the process of determining the mapping relationship based on multiple first signal values ​​and multiple second signal values ​​obtained after each target retaining ring is installed in the polishing equipment, and the groove depth of each target retaining ring, for the same target retaining ring, among the multiple first signal values ​​obtained after the target retaining ring is installed in the polishing equipment, the average of at least some of the first signal values ​​whose difference with the maximum first signal value is less than the first threshold is determined as the first target signal value corresponding to the target retaining ring, and among the multiple second signal values ​​obtained after the target retaining ring is installed in the polishing equipment, the average of at least some of the second signal values ​​or any second signal value is determined as the second target signal value corresponding to the target retaining ring, and then the mapping relationship is determined based on the difference between the first target signal value and the second target signal value corresponding to each target retaining ring, and the groove depth of each target retaining ring.

[0054] In a specific embodiment, the formula for constructing the mapping relationship is H=F(Sig ring -Sig base ), where H is the groove depth, Sig ring -Sig base For the function F(Sig ring -Sig base )’s independent variable, Sig ring To maintain the first target signal value of ring 2, Sig base To maintain the second target signal value of loop 2, F(Sig ring -Sig base) is an unknown function, and then for each target holding ring, the mean of the first signal values ​​whose difference with the maximum first signal value is less than the first threshold value is determined as the first target signal value corresponding to the target holding ring among the multiple first signal values ​​obtained after the target holding ring is installed in the polishing equipment, and the mean of at least part of the second signal values ​​or any second signal value is determined as the second target signal value corresponding to the target holding ring among the multiple second signal values ​​obtained after the target holding ring is installed in the polishing equipment, and then the first target signal value and the second target signal value corresponding to each target holding ring, as well as the groove depth of each target holding ring are substituted into the above formula, and F(Sig ring -Sig base ), the determined F(Sig ring -Sig base ) is usually a linear function or a quadratic function, etc.

[0055] Therefore, since the first signal value is the signal value output by the eddy current sensor when the metal part in the ring 2 is kept opposite to the eddy current sensor 51 in the direction perpendicular to the polishing pad 3 during the operation of the polishing device; the second signal value is the signal value output by the eddy current sensor when the metal part in the ring 2 and the space enclosed by the metal part are not opposite to the eddy current sensor 51 in the direction perpendicular to the polishing pad 3 during the operation of the polishing device; and the first target signal value Sig ring is determined based on the first signal value, the second target signal value Sig base is determined according to the second signal value, so Sig ring and Sig base The mapping relationship between the difference and the groove depth H of the retaining ring is established, which can reduce the error of the output signal of the eddy current sensor caused by factors such as environmental conditions and improve the accuracy of the mapping relationship.

[0056] The above-mentioned first threshold can be determined as follows: the preset first threshold can be directly obtained, or the smallest first signal value among the preset number of first signal values ​​closest to the maximum first signal value obtained after the target retaining ring is installed on the polishing equipment can be determined as the first threshold. The specific value of the preset number can be set according to actual conditions, and the embodiment of the present application does not limit this.

[0057] The specific processing method for determining any second signal value as the second target signal value corresponding to the target retaining ring can be as follows: the target position of the eddy current sensor 51 can be preset, and when the eddy current sensor 51 is driven by the polishing disk 5 to rotate around the axis of the polishing surface 31 to the target position, the polishing equipment operates in the second state. Based on this, among the multiple second signal values ​​obtained after the target retaining ring is installed on the polishing equipment, the second signal value output by the eddy current sensor 51 when the eddy current sensor 51 is moved to the target position can be determined as the second target signal value corresponding to the target retaining ring.

[0058] In the embodiment of the present application, among the multiple first signal values ​​obtained after the target retaining ring is installed on the polishing device, the mean of at least part of the first signal values ​​whose difference with the largest first signal value is less than the first threshold value is determined as the first target signal value corresponding to the target retaining ring, and among the multiple second signal values ​​obtained after the target retaining ring is installed on the polishing device, the mean of at least part of the second signal values ​​or any second signal value is determined as the second target signal value corresponding to the target retaining ring, and then the mapping relationship is determined according to the first target signal value and the second target signal value corresponding to each target retaining ring, and the groove depth of each target retaining ring. Therefore, since the first target signal value corresponding to the target retaining ring is determined according to the mean of the larger first signal value, the difference between the first target signal value and the second target signal value can more accurately reflect the influence of the metal part in the retaining ring 2 on the output signal of the eddy current sensor 51, and since the second target signal value corresponding to the target retaining ring is determined according to the mean of at least part of the second signal values ​​or any second signal value, the determination logic is simple, computing resources are saved, and the efficiency of determining the mapping relationship is improved.

[0059] Based on this, the above step 402 may include the following specific processing: in the process of chemical mechanical polishing of the wafer by the polishing device, the first target signal value and the second target signal value corresponding to the retaining ring 2 installed in the polishing device are obtained; the above step 403 may include the following specific processing: according to the above mapping relationship and the first target signal value and the second target signal value corresponding to the retaining ring 2 are substituted into the mapping relationship H=F(Sig ring -Sig base ), the obtained H is the current groove depth of the retaining ring 2.

[0060] In a possible implementation, the above step 404 may include the following specific processing: if the current groove depth of the retaining ring 2 is less than the initial groove depth of the retaining ring 2 , increasing the pressure between the edge of the wafer and the polishing pad 3 .

[0061] In a specific embodiment, the difference between the current groove depth and the initial groove depth can be determined, and the corresponding pressure increase can be determined based on the difference, and the pressure between the edge of the wafer and the polishing pad 3 can be increased by the pressure increase. The difference between the current groove depth and the initial groove depth is positively correlated with the pressure increase. For example, the difference between the current groove depth and the initial groove depth is proportional to the pressure increase.

[0062] In the embodiment of the present application, when the current groove depth of the retaining ring 2 is less than the initial groove depth of the retaining ring 2, the pressure between the edge of the wafer and the polishing pad 3 is increased. Thus, when the current groove depth of the retaining ring 2 is small (for example, less than the initial groove depth of the retaining ring 2), the increased pressure between the edge of the wafer and the polishing pad 3 can offset the reduced pressure between the retaining ring 2 and the polishing pad 3 caused by the shallowing of the groove 21 of the retaining ring 2, so that the pressure between the edge of the wafer and the polishing pad 3 is relatively consistent at the beginning, during and at the end of the use of the retaining ring 2 of the polishing equipment, without a large pressure change, so that the effect of chemical mechanical polishing of the wafer is relatively stable.

[0063] In a possible implementation, the pressure adjustment method also includes the following specific processing: during the process of chemical mechanical polishing of the wafer by the polishing equipment, the thickness of the wafer installed in the polishing equipment is determined according to the output signal of the eddy current sensor 51, and when the thickness of the wafer is less than a second threshold, the polishing equipment is controlled to stop working, wherein the surface of the wafer is a metal film layer.

[0064] Among them, the specific value of the second threshold can be set according to actual needs, and the embodiment of the present application does not limit this.

[0065] In a specific embodiment, during the process of chemical mechanical polishing of a wafer by a polishing device, the thickness of the wafer installed in the polishing device can be determined based on the signal value output by the eddy current sensor 51 when the wafer is opposite to the eddy current sensor 51 in a direction perpendicular to the polishing pad 3, by using a table lookup method or a formula calculation method, and when it is determined that the thickness of the wafer is less than a second threshold value, the polishing device is controlled to stop chemical mechanical polishing of the wafer to reduce the possibility of over-polishing of the wafer and improve the quality of polishing the wafer.

[0066] Corresponding to the above method embodiment, Figure 7 A schematic diagram of a pressure adjustment device according to an embodiment of the present application is shown. Figure 7 As shown, the pressure regulating device 700 includes:

[0067] a relationship acquisition unit 701, for acquiring a mapping relationship between a groove depth of a retaining ring 2 included in a polishing device and a signal output by an eddy current sensor 51 when the polishing device is working, wherein the polishing device is used to perform chemical mechanical polishing on a wafer, the retaining ring 2 includes an annular metal portion located inside the retaining ring 2, the groove of the retaining ring 2 is provided on a side of the retaining ring 2 close to the polishing pad 3, the eddy current sensor 51 and the retaining ring 2 are located on both sides of the polishing pad 3 included in the polishing device, and during the process of chemical mechanical polishing of the wafer by the polishing device, the metal portion in the retaining ring 2 is opposite to the eddy current sensor 51 in a direction perpendicular to the polishing pad 3 for at least part of the time;

[0068] The signal acquisition unit 702 is used to acquire the output signal of the eddy current sensor 51 during the chemical mechanical polishing process of the wafer by the polishing equipment;

[0069] A depth determination unit 703, used to determine the current groove depth of the retaining ring 2 according to the mapping relationship and the above output signal;

[0070] The pressure adjustment unit 704 is used to adjust the pressure between the edge of the wafer and the polishing pad 3 according to the current groove depth.

[0071] In an embodiment of the present application, the relationship acquisition unit 701 can obtain the mapping relationship between the groove depth of the retaining ring 2 and the signal output by the eddy current sensor 51 when the polishing equipment is working. The signal acquisition unit 702 obtains the output signal of the eddy current sensor 51 during the chemical mechanical polishing process. The depth determination unit 703 determines the current groove depth of the retaining ring 2 based on the acquired mapping relationship and the above-mentioned output signal. The pressure adjustment unit 704 adjusts the pressure between the edge of the wafer and the polishing pad 3 according to the current groove depth. Therefore, after the polishing equipment has been used for a period of time, even if the groove depth of the retaining ring 2 becomes smaller due to wear or other reasons, the current groove depth of the retaining ring 2 can be detected, and the pressure between the edge of the wafer and the polishing pad 3 can be adjusted according to the current groove depth. Compared with the related art of adjusting the pressure between the edge of the wafer polished by the polishing equipment and the polishing pad 3 at regular intervals, the present application adjusts the pressure according to the specific value of the current groove depth, and thus the timing and amount of the pressure adjustment are more accurate, which can reduce the possibility of excessive or insufficient pressure between the edge of the wafer and the polishing pad 3 during the polishing process, thereby optimizing the effect of chemical mechanical polishing of the edge of the wafer.

[0072] It should be noted that the pressure adjustment device of this embodiment is used to implement the corresponding pressure adjustment method in the aforementioned method embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0073] Figure 8This is a schematic block diagram of an electronic device provided in an embodiment of the present application. The specific embodiment of the present application does not limit the specific implementation of the electronic device. Figure 8 As shown, the electronic device may include: a processor (processor) 802, a communication interface (Communications Interface) 804, a memory (memory) 806, and a communication bus 808. Among them:

[0074] The processor 802 , the communication interface 804 , and the memory 806 communicate with each other via a communication bus 808 .

[0075] The communication interface 804 is used to communicate with other electronic devices or servers.

[0076] The processor 802 is used to execute the program 810, and specifically can execute the relevant steps in any of the aforementioned pressure adjustment method embodiments.

[0077] Specifically, the program 810 may include program codes, which include computer operation instructions.

[0078] The processor 802 may be a CPU, or an application specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application. The one or more processors included in the smart device may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0079] RISC-V is an open source instruction set architecture based on the Reduced Instruction Set (RISC) principle. It can be applied to various aspects such as single-chip microcomputers and FPGA chips. Specifically, it can be applied to the fields of IoT security, industrial control, mobile phones, personal computers, etc., and because it is designed with small, fast, and low-power realities in mind, it is particularly suitable for modern computing devices such as warehouse-scale cloud computers, high-end mobile phones, and tiny embedded systems. With the rise of artificial intelligence Internet of Things (AIoT), the RISC-V instruction set architecture has also received more and more attention and support, and is expected to become the next generation of widely used CPU architecture.

[0080] The computer operation instructions in the embodiment of the present application may be computer operation instructions based on the RISC-V instruction set architecture, and correspondingly, the processor 802 may be designed based on the RISC-V instruction set. Specifically, the chip of the processor in the electronic device provided in the embodiment of the present application may be a chip designed with the RISC-V instruction set, and the chip may execute executable code based on the configured instructions, thereby realizing the pressure adjustment method in the above embodiment.

[0081] The memory 806 is used to store the program 810. The memory 806 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0082] The program 810 may be specifically used to enable the processor 802 to execute the pressure adjustment method in any of the aforementioned embodiments.

[0083] The specific implementation of each step in program 810 can refer to the corresponding description of the corresponding steps and units in any of the above-mentioned pressure adjustment method embodiments, which will not be repeated here. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the above-described devices and modules can refer to the corresponding process description in the above-mentioned method embodiments, which will not be repeated here.

[0084] Through the electronic device of the embodiment of the present application, after the polishing equipment has been used for a period of time, even if the groove depth of the retaining ring 2 becomes smaller due to wear or other reasons, the current groove depth of the retaining ring 2 can be detected, and the pressure between the edge of the wafer and the polishing pad 3 can be adjusted according to the current groove depth. Compared with the related art of adjusting the pressure between the edge of the wafer polished by the polishing equipment and the polishing pad 3 at regular intervals, the present application adjusts the pressure according to the specific value of the current groove depth, and thus the timing and amount of the pressure adjustment are more accurate, which can reduce the possibility of excessive or insufficient pressure between the edge of the wafer and the polishing pad 3 during the polishing process, thereby optimizing the effect of chemical mechanical polishing of the edge of the wafer.

[0085] The present application also provides a computer-readable storage medium storing instructions for causing a machine to execute the pressure adjustment method as described herein. Specifically, a system or device equipped with a storage medium may be provided, on which a software program code for implementing the functions of any of the above-mentioned embodiments is stored, and a computer (or CPU or MPU) of the system or device reads and executes the program code stored in the storage medium.

[0086] In this case, the program code read from the storage medium itself can implement the function of any one of the above embodiments, so the program code and the storage medium storing the program code constitute part of the present application.

[0087] The storage medium embodiments for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer via a communication network.

[0088] An embodiment of the present application also provides a computer program product, including computer instructions, which instruct a computing device to perform any corresponding operation in the above-mentioned multiple method embodiments.

[0089] It should be pointed out that, according to the needs of implementation, the various components / steps described in the embodiments of the present application can be split into more components / steps, or two or more components / steps or partial operations of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of the present application.

[0090] The above-mentioned method according to the embodiment of the present application can be implemented in hardware, firmware, or implemented as software or computer code that can be stored in a recording medium (such as a CD ROM, RAM, floppy disk, hard disk or magneto-optical disk), or implemented as a computer code originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded through a network and to be stored in a local recording medium, so that the method described herein can be stored in such software processing on a recording medium using a general-purpose computer, a special-purpose processor or programmable or special-purpose hardware (such as an ASIC or FPGA). It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component (e.g., RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by a computer, a processor or hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown here, the execution of the code converts the general-purpose computer into a special-purpose computer for executing the method shown here.

[0091] Those of ordinary skill in the art will appreciate that the units and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for specific applications, but such implementation should not be considered to be beyond the scope of the embodiments of the present application.

[0092] The above implementation methods are only used to illustrate the embodiments of the present application, and are not limitations on the embodiments of the present application. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application. The scope of patent protection of the embodiments of the present application should be limited by the claims.

Claims

1. A pressure adjustment method, characterized in that: include: Acquiring a mapping relationship between a groove depth of a retaining ring included in a polishing device and a signal output by an eddy current sensor when the polishing device is working, wherein the polishing device is used to perform chemical mechanical polishing on a wafer and includes a polishing pad, the retaining ring includes an annular metal portion located inside the retaining ring, the groove of the retaining ring is opened on a side of the retaining ring close to the polishing pad, the eddy current sensor and the retaining ring are located on both sides of the polishing pad, and during the process of chemical mechanical polishing of the wafer by the polishing device, the metal portion in the retaining ring is opposite to the eddy current sensor in a direction perpendicular to the polishing pad at least part of the time; During the process of chemical mechanical polishing of the wafer by the polishing equipment, obtaining an output signal of the eddy current sensor; Determining a current groove depth of the retaining ring according to the mapping relationship and the output signal; adjusting the pressure between the edge of the wafer and the polishing pad according to the current groove depth; The obtaining of the output signal of the eddy current sensor comprises: obtaining a first output signal of the eddy current sensor when the polishing device is operating in a first state, and a second output signal of the eddy current sensor when the polishing device is operating in a second state, wherein the first state is a state in which the metal part in the retaining ring is opposite to the eddy current sensor in a direction perpendicular to the polishing pad, and the second state is a state in which the metal part in the retaining ring and the space enclosed by the metal part are not opposite to the eddy current sensor in a direction perpendicular to the polishing pad; Determining the current groove depth of the retaining ring according to the mapping relationship and the output signal includes: determining the current groove depth of the retaining ring according to the mapping relationship, the first output signal, and the second output signal.

2. The method according to claim 1, characterized in that The method further comprises: obtaining groove depths of a plurality of target retaining rings having different groove depths; After the target retaining ring is installed on the polishing device, the polishing device is controlled to work so that the polishing pad in the polishing device rotates at least one circle, and when the polishing device is working in the first state, a plurality of first signal values ​​output by the eddy current sensor at different times are obtained, and when the polishing device is working in the second state, a plurality of second signal values ​​output by the eddy current sensor at different times are obtained; The mapping relationship is determined according to a plurality of first signal values ​​and a plurality of second signal values ​​acquired after each of the target retaining rings is installed in the polishing device, and a groove depth of each of the target retaining rings.

3. The method according to claim 2, characterized in that Determining the mapping relationship according to a plurality of first signal values ​​and a plurality of second signal values ​​obtained after each target retaining ring is installed on the polishing device, and a groove depth of each target retaining ring, comprises: Among a plurality of first signal values ​​acquired after the target holding ring is installed on the polishing device, an average of first signal values ​​whose difference with the largest first signal value is less than a first threshold is determined as a first target signal value corresponding to the target holding ring; Among a plurality of second signal values ​​acquired after the target retaining ring is installed on the polishing device, an average value of at least part of the second signal values ​​or any second signal value is determined as a second target signal value corresponding to the target retaining ring; The mapping relationship is determined according to the difference between the first target signal value and the second target signal value corresponding to each target holding ring and the groove depth of each target holding ring.

4. The method according to claim 1, characterized in that The step of adjusting the pressure between the edge of the wafer and the polishing pad according to the current groove depth includes: If the current groove depth is less than the initial groove depth of the retaining ring, the pressure between the edge of the wafer and the polishing pad is increased.

5. The method according to claim 1, characterized in that The method further comprises: During the process of chemical mechanical polishing of the wafer by the polishing equipment, the thickness of the wafer installed in the polishing equipment is determined according to the output signal of the eddy current sensor, and when the thickness of the wafer is less than a second threshold, the polishing equipment is controlled to stop working, wherein the surface of the wafer is a metal film layer.

6. A pressure regulating device, characterized in that: include: a relationship acquisition unit, used for acquiring a mapping relationship between a groove depth of a retaining ring included in a polishing device and a signal output by an eddy current sensor when the polishing device is working, wherein the polishing device is used for chemical mechanical polishing of a wafer and includes a polishing pad, the retaining ring includes an annular metal portion located inside the retaining ring, the groove of the retaining ring is opened on a side of the retaining ring close to the polishing pad, the eddy current sensor and the retaining ring are located on both sides of the polishing pad, and during the process of chemical mechanical polishing of the wafer by the polishing device, the metal portion in the retaining ring is opposite to the eddy current sensor in a direction perpendicular to the polishing pad at least part of the time; a signal acquisition unit, used for acquiring an output signal of the eddy current sensor during a process in which the polishing device performs chemical mechanical polishing on a wafer, wherein acquiring the output signal of the eddy current sensor comprises: acquiring a first output signal of the eddy current sensor during a process in which the polishing device operates in a first state, and acquiring a second output signal of the eddy current sensor during a process in which the polishing device operates in a second state, wherein the first state is a state in which the metal part in the retaining ring is opposite to the eddy current sensor in a direction perpendicular to the polishing pad, and the second state is a state in which the metal part in the retaining ring and the space enclosed by the metal part are not opposite to the eddy current sensor in a direction perpendicular to the polishing pad; A depth determination unit, configured to determine a current groove depth of the retaining ring according to the mapping relationship and the output signal, comprising: determining a current groove depth of the retaining ring according to the mapping relationship, the first output signal, and the second output signal; The pressure adjustment unit is used to adjust the pressure between the edge of the wafer and the polishing pad according to the current groove depth.

7. An electronic device, characterized in that: The electronic device comprises: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute an operation corresponding to the method according to any one of claims 1 to 5.

8. A computer storage medium, characterized in that: The computer storage medium stores a computer program, which, when executed by a processor, implements the method according to any one of claims 1 to 5.

9. A computer program product, characterized in that The computer program product comprises computer instructions, which instruct a computing device to execute the method according to any one of claims 1-5.

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