TWI896473B - Pressure adjustment method, pressure adjustment apparatus, electronic apparatus, computer storage medium, and computer program product - Google Patents

Abstract

A pressure adjustment method, a pressure adjustment apparatus, an electronic equipment, a computer storage medium and a computer program product are provided in the embodiments of the present disclosure. The method includes obtaining the mapping relationship between a groove depth of a retaining ring included in a polishing device and a signal output by an eddy current sensor during operation of the polishing device. The eddy current sensor and the retaining ring are disposed on opposite sides of a polishing pad included in the polishing device. A metal portion included in the holding ring is at least partially opposite to the eddy current sensor in a direction perpendicular to the polishing pad in a process of chemical mechanical polishing of a wafer by the polishing device; obtaining an output signal of the eddy current sensor during the process of chemical mechanical polishing of the wafer by the polishing device; determining a current groove depth of the retaining ring based on the mapping relationship and the output signal to adjust the pressure between an edge of the wafer and the polishing pad.

Description

Pressure adjustment method, pressure adjustment device, electronic equipment, computer storage medium and computer program product

This application relates to the field of wafer polishing technology, and more particularly to a pressure adjustment method, a pressure adjustment device, an electronic device, a computer storage medium, and a computer program product.

During the integrated circuit manufacturing process, chemical mechanical polishing (CMP) is used to flatten the wafer surface. CMP can be achieved through polishing equipment.

As shown in Figures 1 and 2, the polishing equipment includes a carrier head 1, a holding ring 2 and a polishing pad 3. The carrier head 1 and the holding ring 2 are both located above the polishing pad 3. The holding ring 2 is located below the carrier head 1. One annular surface of the holding ring 2 is connected to the carrier head 1. A groove 21 is provided on the other annular surface of the holding ring 2. The lower end of the carrier head 1 is connected to a lower pressing member 4. The holding ring 2 is arranged outside the lower pressing member 4. In the process of using the polishing equipment, the wafer is first placed in the space enclosed by the holding ring 2 and adjusted. The entire retaining ring 2 is brought into contact with the polishing pad 3. The wafer now abuts between the lower pressure member 4 and the polishing pad 3. The lower pressure member 4 is then controlled to provide a downward pressure to ensure an appropriate level of pressure between the wafer and the polishing pad 3. The carrier head 1 and the polishing pad 3 are then controlled to move relative to each other, causing the wafer and retaining ring 2 to move along the upper surface of the polishing pad 3. Simultaneously, the polishing liquid sprayed onto the polishing pad 3 can fully contact the wafer within the retaining ring 2 through the grooves 21 of the retaining ring 2, achieving chemical mechanical polishing of the wafer.

However, after the polishing equipment has been used for a period of time, the retaining ring 2 will be worn out, so that the depth of the groove 21 of the retaining ring 2 will decrease. In turn, the pressure between the retaining ring 2 and the polishing pad 3 will decrease, and the pressure between the edge of the wafer and the polishing pad 3 will also decrease. In response to this situation, some operators will increase the pressure of the lower pressure member 4 on the edge of the wafer during the polishing process at regular intervals. However, due to the varying polishing frequencies, the pressure of the lower pressure member 4 on the edge of the wafer will not increase. Due to reasons such as irregularities in the polishing process and the non-unique polishing conditions, the wear of the retaining ring 2 does not change regularly with increasing polishing time. As a result, when the pressure of the lower 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. This 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, resulting in a poor chemical mechanical polishing effect on the edge of the wafer.

In view of this, the present application provides a pressure adjustment method, a pressure adjustment device, an electronic device, a computer storage medium and a computer program product to at least partially solve the above problems.

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 electro-vortex flow sensor when the polishing device is in operation, 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 formed on a side surface of the retaining ring close to the polishing pad, the electro-vortex flow sensor and the retaining ring are located On both sides of the polishing pad, during chemical mechanical polishing of the wafer by the polishing equipment, the metal portion within the retaining ring is opposite the electro-eddy current sensor in a direction perpendicular to the polishing pad for at least part of the time; during chemical mechanical polishing of the wafer by the polishing equipment, an output signal of the electro-eddy current sensor is obtained; a current trench depth of the retaining ring is determined based on the mapping relationship and the output signal; and the pressure between the edge of the wafer and the polishing pad is adjusted based on the current trench depth.

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 electro-vortex flow sensor when the polishing device is in operation, wherein the polishing device is used to perform chemical mechanical polishing on wafers and includes a polishing pad; the retaining ring includes an annular metal portion located within the retaining ring; the groove of the retaining ring is formed on a side surface of the retaining ring adjacent to the polishing pad; the electro-vortex flow sensor and the retaining ring are located on both sides of the polishing pad; During chemical mechanical polishing of the wafer by the polishing apparatus, the metal portion within the retaining ring is opposed to the electro-eddy current sensor at least partially in a direction perpendicular to the polishing pad. A signal acquisition unit is configured to acquire an output signal from the electro-eddy current sensor during chemical mechanical polishing of the wafer by the polishing apparatus. A depth determination unit is configured to determine a current trench depth of the retaining ring based on the mapping relationship and the output signal. A pressure adjustment unit is configured to adjust the pressure between the edge of the wafer and the polishing pad based on the current trench depth.

According to a third aspect of the embodiments of the present application, an electronic device is provided, 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 causes the processor to execute an operation corresponding to the method described in the embodiment of the first aspect above.

According to a fourth aspect of the embodiments 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 described in the embodiment of the first aspect above.

According to a fifth aspect of the embodiment of the present application, a computer program product is provided, comprising computer instructions, which instruct a computing device to execute the method described in the embodiment of the first aspect above.

According to the pressure adjustment scheme provided in the embodiment of the present application, a mapping relationship can be obtained between the groove depth of the retaining ring and the signal output by the electro-vortex sensor when the polishing equipment is operating. During the chemical mechanical polishing process, the output signal of the electro-vortex sensor is obtained. Then, based on the obtained mapping relationship and the above-mentioned output signal, the current groove depth of the retaining ring is determined. Then, based on the current groove depth, the pressure between the edge of the wafer and the polishing pad is adjusted. Therefore, after the polishing equipment has been used for a period of time, even if the groove depth of the retaining ring becomes smaller due to wear and tear, 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 of adjusting the edge of the wafer polished by the polishing equipment at regular intervals, the pressure between the edge of the wafer polished by the polishing equipment can be adjusted at regular intervals. The pressure between the edge of the wafer and the polishing pad is adjusted according to the specific value of the current groove depth. As a result, the timing and amount of 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. Therefore, the effect of chemical mechanical polishing on the edge of the wafer is optimized.

To help those skilled in the art better understand the technical solutions in the embodiments of this application, the following will provide a clear and complete description of the technical solutions in the embodiments of this application, in conjunction with the diagrams in the embodiments of this application. Obviously, the described embodiments are only a portion of the embodiments of this application, not all of them. All other embodiments derived by those skilled in the art based on the embodiments of this application should fall within the scope of protection of the embodiments of this application.

Application environment of this application

This application embodiment proposes a pressure adjustment scheme. The entire pressure adjustment scheme can be used to adjust the pressure between the edge of a wafer and a polishing pad during chemical mechanical polishing of the wafer. The pressure adjustment scheme can be executed by data centers, servers, personal computers, Internet of Things (IoT) devices, embedded devices, and the like. The pressure adjustment scheme is independent of the hardware deployed in the computing device executing the scheme.

Pressure adjustment method

The present application provides a pressure adjustment method for adjusting the pressure between the edge of the wafer and the polishing pad during chemical mechanical polishing of the wafer by a polishing device.

Figure 3 is a cross-sectional view of a polishing apparatus according to an embodiment of the present application. As shown in Figure 3, the polishing apparatus comprises a carrier head 1, a retaining ring 2, a polishing pad 3, and a polishing plate 5. The structure of retaining ring 2 is as shown in Figure 2. Retaining ring 2 includes a metal portion located within retaining ring 2. Both retaining ring 2 and the metal portion are annular in shape, and the axis of retaining ring 2 as a whole coincides with the axis of the metal portion. Both carrier head 1 and retaining ring 2 are located above polishing pad 3, while retaining ring 2 is located below carrier head 1. The carrier head 1 presses the wafer onto the polishing pad 3 covering the surface of the polishing plate 5. The carrier head 1 rotates and reciprocates along the radial direction of the polishing plate 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 supporting 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 pass through from the inner side surface of the retaining ring 2 to the outer side surface of the retaining ring 2; the lower end of the supporting head 1 is also connected to a pressing member 4, and the retaining ring 2 is arranged outside the pressing member 4, and the pressing member 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. The polishing pad 3 is fixedly connected to the polishing disk 5 or detachably fixed. The polishing pad 3 has a circular outer surface, a polishing surface 31 (i.e., the upper surface of the polishing pad 3 in the polishing equipment) for polishing wafers, and the retaining ring 2 has a diameter smaller than the diameter of the polishing surface 31. An eddy current sensor 51 is mounted within the polishing plate 5, such that the eddy current sensor 51 and the retaining ring 2 are located on either side of the polishing pad 3. The eddy current sensor 51 is in contact with the lower side of the polishing pad 3. The signal output by the eddy current sensor 51 is an eddy current signal, such as a voltage signal or a current signal, which is not limited in this embodiment of the present application.

During the chemical mechanical polishing process of the polishing equipment, the wafer is first placed in the space surrounded by the holding ring 2, and the holding ring 2 is adjusted to abut against the polishing surface 31. At this time, the wafer abuts between the lower pressure member 4 and the polishing pad 3. The lower pressure member 4 is then 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 holding ring 2 move along the polishing surface 31 of the polishing pad 3. For example, the carrier head 1 can be controlled to move relative to the polishing pad 3. The support head 1 drives the holding ring 2 and the wafer to rotate around the axis of the holding ring 2, and controls the support head 1 to drive the holding ring 2 and the wafer to reciprocate along any radius of the polishing surface 31. The polishing plate 5 also controls 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 holding ring 2 through the grooves 21 of the holding ring 2, thereby realizing chemical mechanical polishing of the wafer.

During the chemical mechanical polishing process of the wafer by the polishing equipment, the metal portion in the ring 2 is kept facing the eddy current sensor 51 at least part of the time in the direction perpendicular to the polishing pad 3; when the metal portion on the ring 2 and the space enclosed by the metal portion are not facing the eddy current sensor 51 in the direction perpendicular to the polishing pad 3, that is, the metal portion on the ring 2 is not in the straight line passing through the eddy current sensor 51 and perpendicular to the polishing surface 31. When the metal portion of the ring 2 is kept on the straight line and the space enclosed by the metal portion of 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 portion of the ring 2 is kept opposite to the eddy current sensor 51 in a direction perpendicular to the polishing pad 3, that is, when the metal portion of the ring 2 is kept on the straight line, the metal portion 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.

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

FIG4 is a flow chart of a pressure adjustment method according to an embodiment of the present application. As shown in FIG4 , the pressure adjustment method includes the following steps:

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

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 electro-eddy current sensor 51 when the polishing device is operating. For example, the mapping relationship can be: groove depth H = F(B), where the function F(B) is a linear function, a quadratic function, or another functional expression, such as H = A*B, where A is a proportionality factor and B is the maximum signal value output by the electro-eddy current sensor 51 when the polishing device is operating. Multiple sets of corresponding specific values of H and B can be determined in advance through experiments, and A can be determined through fitting or other methods.

Step 402: During the chemical mechanical polishing process of the wafer by the polishing equipment, the output signal of the electric eddy current sensor 51 is obtained.

Step 403: Determine the current groove depth of retaining ring 2 based on the mapping relationship and the output signal.

In one embodiment, during chemical mechanical polishing of a wafer by a polishing apparatus, each time the polishing pad 3 rotates at least one revolution around the axis of the polishing surface 31 driven by the polishing plate 5, the current groove depth of the retaining ring 2 is determined based on the mapping relationship and the output signal.

For example, based on the above example of H=A*B, during chemical mechanical polishing of a wafer by a polishing apparatus, each time the polishing pad 3 rotates around the axis of the polishing surface 31 under the drive of the polishing plate 5, the maximum signal value B of the output signal of the electro-eddy current sensor 51 during this rotation of the polishing pad 3 can be determined to be b. Substituting B=b into H=A*B yields the current trench depth H as A*b.

Step 404: Adjust the pressure between the edge of the wafer and the polishing pad 3 according to the current trench depth.

In one 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.

In this embodiment of the present application, a mapping relationship can be obtained between the groove depth of the retaining ring 2 and the signal output by the electro-vortex sensor 51 when the polishing equipment is operating. During the chemical mechanical polishing process, the output signal of the electro-vortex sensor 51 is obtained. Then, based on the obtained mapping relationship and the above-mentioned output signal, the current groove depth of the retaining ring 2 is determined. Then, based on the current groove depth, the pressure between the edge of the wafer and the polishing pad 3 is adjusted. Therefore, after the polishing equipment has been used for a period of time, even if the groove depth of the holding ring 2 becomes smaller due to wear or other reasons, the current groove depth of the holding 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 of the wafer polished by the polishing equipment at regular intervals, the pressure of the wafer polished by the polishing equipment can be adjusted at regular intervals. The pressure between the edge and the polishing pad 3 is adjusted in this application based on the specific value of the current groove depth. This allows for more precise adjustment timing and amount, reducing the possibility of excessive or insufficient pressure between the wafer edge and the polishing pad 3 during the polishing process. This optimizes the chemical mechanical polishing effect on the wafer edge.

In addition, in the embodiment of the present application, since the current groove depth of the holding 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 holding ring 2 and then physically measure the groove depth. Therefore, the chemical mechanical polishing of the wafer is faster and more convenient. In addition, since the current groove depth of the holding ring 2 can be continuously detected during the chemical mechanical polishing process, the current groove depth of the holding ring 2 can be determined by the mapping relationship and the output signal of the eddy current sensor 51. The current groove depth of the retaining ring 2 is measured. Therefore, compared to the solution of measuring the initial groove depth of the retaining ring 2 and then inferring the current groove depth of the retaining ring 2 based on the initial groove depth and the polishing time, in this application, even if the polishing environment is more complex and causes the groove depth of the retaining ring 2 to change irregularly, the error of the current groove depth of the retaining ring 2 relative to the actual groove depth is smaller.

In one possible implementation, in the process of obtaining the output signal of the electro-eddy current detector 51 in step 402, a first output signal of the electro-eddy current detector 51 is obtained when the polishing device is operating in the first state, and a second output signal of the electro-eddy current detector 51 is obtained when the polishing device is operating in the second state.

The first state is a state in which the metal portion within the ring 2 is maintained opposite to the eddy current sensor 51 in a direction perpendicular to the polishing pad 3, that is, the metal portion within the ring 2 is maintained directly above the eddy current sensor 51. The second state is a state in which the metal portion within the ring 2 and the space enclosed by the metal portion are maintained opposite to the eddy current sensor 51 in a direction perpendicular to the polishing pad 3, that is, the metal portion within the ring 2 is maintained not above the eddy current sensor 51, and the space enclosed by the metal portion is also not located above the eddy current sensor 51.

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.

Correspondingly, the mapping relationship is the mapping relationship between the groove depth of the ring 2, the signal output by the electro-eddy current detector 51 during the operation of the polishing device in the first state, and the signal output by the electro-eddy current detector 51 during the operation of the polishing device in the second state, based on this:

In a specific embodiment, during the chemical mechanical polishing process of the wafer by the polishing equipment, the first output signal and the second output signal of the electric eddy current sensor 51 can be obtained, so as to utilize the mapping relationship to determine the current trench depth of the retaining ring 2 according to the first output signal and the second output signal.

In this embodiment of the present application, the current groove depth of the ring 2 can be determined based on a first output signal and a second output signal. The first output signal is the output signal of the eddy current detector 51 when the metal portion within the ring 2 is maintained opposite to the eddy current detector 51 in a direction perpendicular to the polishing pad 3. The second output signal is the output signal of the eddy current detector 51 when the metal portion within the ring 2 and the space enclosed by the metal portion are not opposite to the eddy current detector 51 in a 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 electro-eddy current sensor 51 is affected by the retaining ring 2, but also takes into account the situation when the output signal of the electro-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 electro-eddy current sensor 51, thereby improving the accuracy of detecting the current groove depth of the retaining ring 2.

Before step 401, the mapping relationship must be determined first, which can be as follows:

In one possible implementation, the pressure adjustment method further includes: obtaining the groove depths of multiple target retaining rings having different groove depths; after the target retaining rings are installed in the polishing equipment, controlling the operation of the polishing equipment so that the polishing pad 3 in the polishing equipment rotates at least one revolution, and obtaining multiple first signal values output by the electro-eddy current sensor 51 at different times when the polishing equipment operates in the first state, and obtaining multiple second signal values output by the electro-eddy current sensor 51 at different times when the polishing equipment operates in the second state; and determining a 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, as well as the groove depth of each target retaining ring.

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; or the method may include preparing multiple retaining rings 2 with different groove depths, and then changing the groove depth of the retaining rings 2 by polishing for a certain period of time so as to cause the retaining rings 2 to wear, and for each retaining ring 2, determining the retaining ring 2 before wear and the retaining ring 2 after wear as The target retaining ring can be obtained by grinding a plurality of 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. Among them, the method of grinding the retaining ring 2 can be manual grinding or installing the retaining ring 2 in a polishing device for chemical mechanical polishing, etc., and this embodiment of the application is not limited to this.

In a specific embodiment, for each target retaining ring, after obtaining the target retaining ring, 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 rotate the polishing pad 3 in the polishing equipment for at least one revolution. During the process of the polishing equipment working in the first state, the eddy current is obtained. The sensor 51 outputs multiple first signal values at different times. When the polishing device is operating in the second state, multiple second signal values are output by the electro-eddy current sensor 51 at different times. Finally, a 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 device, as well as the groove depth of each target retaining ring.

It should be noted that, in the process of controlling the operation of the polishing equipment after the target holding ring is installed in the polishing equipment, the polishing equipment can be controlled to operate with or without a wafer installed. The embodiment of the present application does not limit this. Operating with a wafer installed means chemical mechanical polishing of the wafer, and operating with no wafer installed means that no wafer is installed in the polishing equipment. However, each part of the polishing equipment operates in a manner of chemical mechanical polishing of the wafer. Operating with no wafer installed can facilitate the acquisition of the mapping relationship and reduce the rejection rate of wafers after chemical mechanical polishing.

For example, for a target holding ring, the groove depth of the target holding ring can be measured, and then the holding ring 2 in the polishing equipment is replaced with the target holding ring. Then, the polishing equipment is controlled to operate in a state where no wafer is installed until the polishing pad 3 in the polishing equipment rotates one circle. During the operation of the polishing equipment, the signal value output by the electric eddy current detector 51 is obtained multiple times. The result of obtaining the signal value is shown in Figure 5. The vertical coordinate in Figure 5 is the signal value output by the electric eddy current detector 51, and the horizontal coordinate is the working time of the polishing equipment. The multiple signal values output by the electric eddy current detector 51 in Figure 5 are shown in Figure 5. Some of the signal values in FIG5 are first signal values, and other signal values are second signal values. In addition, among the multiple signal values output by the electro-eddy current sensor 51 in FIG5 , signal values other than the first and second signal values are third signal values. The third signal value is the signal value output by the electro-eddy current sensor 51 when the polishing device is operating in the third state. The third state is a state in which the space enclosed by the metal portion within the ring 2 is maintained opposite to the electro-eddy current sensor 51 in a direction perpendicular to the polishing pad 3, that is, the space enclosed by the metal portion within the ring 2 is maintained directly above the electro-eddy current sensor 51.

In addition, since the groove depths of different target holding rings are different, the maximum first signal value output by the electric eddy current sensor 51 during the process of controlling the polishing equipment to operate without a wafer mounted thereon after the different target holding rings are mounted thereon is also different. For example, FIG6 is a schematic diagram of the signal values corresponding to different target holding rings in one embodiment of the present application. As shown in FIG6 , the vertical coordinate is the signal value output by the electric eddy current sensor 51, and the horizontal coordinate is the time during which the polishing equipment operates. The signal value indicated by the triangle point in FIG6 is the signal value output by the electric eddy current sensor 51 after the first target holding ring is mounted thereon, and the polishing equipment is controlled to operate with a wafer mounted thereon. The signal values output by the electric eddy current sensor 51 during operation without a wafer mounted on the polishing apparatus are shown in Figure 6 . The circular points in Figure 6 indicate the signal values output by the electric eddy current sensor 51 during operation without a wafer mounted on the polishing apparatus after the second target holding ring is mounted on the polishing apparatus. The cross points in Figure 6 indicate the signal values output by the electric eddy current sensor 51 during operation without a wafer mounted on the polishing apparatus after the third target holding ring is mounted on the polishing apparatus. As can be seen from Figure 6 , the maximum first signal values corresponding to different target holding rings are different.

In one possible implementation, in a process of determining a mapping relationship based on a plurality of first signal values and a plurality of second signal values obtained after each target retaining ring is mounted on the polishing apparatus, and the groove depth of each target retaining ring, for the same target retaining ring, among the plurality of first signal values obtained after the target retaining ring is mounted on the polishing apparatus, an average of at least some of the first signal values whose difference from the maximum first signal value is less than a first threshold value is taken as the average value. The target holding ring is determined as the first target signal value corresponding to the target holding ring, and among the multiple second signal values obtained after the target holding ring is installed in the polishing equipment, the average 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, and then 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.

In a specific embodiment, the mapping relationship can be constructed as a formula H=F(Sig _ring -Sig _base ), where H is the groove depth, Sig _ring -Sig _base is the argument of the function F(Sig _ring -Sig _base ), Sig _ring is the first target signal value of the holding ring 2, and Sig _base is the second target signal value of the holding ring 2. In this case, F(Sig _ring -Sig _base ) is an unknown function, and then for each target retaining ring, among multiple first signal values obtained after the target retaining ring is installed in the polishing equipment, the average 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 multiple second signal values obtained after the target retaining ring is installed in the polishing equipment, the average 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 first target signal value and the second target signal value corresponding to each target retaining ring, as well as the groove depth of each target retaining ring are substituted into the above formula, and F(Sig _ring -Sig _base ) is determined by fitting or the like. The determined F(Sig _ring -Sig _base ) is usually a linear function or a quadratic function, etc.

Therefore, since the first signal value is the signal value output by the eddy current detector when the metal portion in the ring 2 is kept opposite to the eddy current detector 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 detector when the metal portion in the ring 2 and the space enclosed by the metal portion are not opposite to the eddy current detector 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, and the second target signal value Sig _base is determined based on the second signal value, therefore, the Sig _ring and Sig base are used. The difference between _{the base} and the groove depth H of the holding ring is used to establish a mapping relationship. This can reduce the error in the output signal of the electric eddy current sensor caused by factors such as environmental conditions and improve the accuracy of the mapping relationship.

The first threshold value may be determined as follows: a preset first threshold value may be directly obtained, or the smallest first signal value among a preset number of first signal values closest to the largest first signal value among multiple first signal values obtained after the target retaining ring is installed in the polishing equipment may be determined as the first threshold value. The specific value of the preset number may be set according to actual circumstances, and this embodiment of the application does not limit this.

The specific processing method for determining any second signal value as the second target signal value corresponding to the target holding ring can be as follows: a target position of the electro-eddy current sensor 51 can be preset. When the electro-eddy current sensor 51 is driven by the polishing disk 5 to rotate about 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 holding ring is installed in the polishing equipment, the second signal value output by the electro-eddy current sensor 51 when the electro-eddy current sensor 51 moves to the target position can be determined as the second target signal value corresponding to the target holding ring.

In this embodiment of the application, among the multiple first signal values obtained after the target holding ring is installed on 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 value is determined as the first target signal value corresponding to the target holding ring, and among the multiple second signal values obtained after the target holding ring is installed on 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 holding 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 holding ring, and the groove depth of each target holding ring. Therefore, since the first target signal value corresponding to the target holding ring is determined based on the average of the larger first signal values, the difference between the first target signal value and the second target signal value can more accurately reflect the impact of the metal part in the holding ring 2 on the output signal of the electro-vortex flow sensor 51. Furthermore, since the second target signal value corresponding to the target holding ring is determined based on the average 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.

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

In one possible implementation, 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.

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

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 relatively small (e.g., 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 decreased pressure between the retaining ring 2 and the polishing pad 3 caused by the shallowing of the groove 21 of the retaining ring 2. This allows the pressure between the edge of the wafer and the polishing pad 3 to be relatively consistent at the beginning, during, and end of use of the retaining ring 2 of the polishing equipment, without significant pressure fluctuations. This ensures a more stable chemical mechanical polishing effect on the wafer.

In one possible implementation, the pressure adjustment method further 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 based on 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.

The specific value of the second threshold can be set according to actual needs and is not limited in this embodiment of the application.

In one specific embodiment, while the polishing equipment is performing chemical mechanical polishing on a wafer, the thickness of the wafer mounted in the polishing equipment can be determined by a lookup table or formula calculation based on the signal value output by the eddy current sensor 51 when the wafer and the eddy current sensor 51 are facing each other in a direction perpendicular to the polishing pad 3. When it is determined that the thickness of the wafer is less than a second threshold, the polishing equipment is controlled to stop chemical mechanical polishing on the wafer, thereby reducing the possibility of over-polishing the wafer and improving the quality of the wafer polishing.

Pressure adjustment device

Corresponding to the above method embodiment, FIG7 shows a schematic diagram of a pressure adjustment device according to an embodiment of the present application. As shown in FIG7 , the pressure adjustment device 700 includes:

The relationship acquisition unit 701 is used to obtain the mapping relationship between the groove depth of the holding ring 2 included in the polishing device and the signal output by the electric eddy current sensor 51 when the polishing device is working, wherein the polishing device is used to perform chemical mechanical polishing on the wafer, the holding ring 2 includes an annular metal part located inside the holding ring 2, and the holding ring 2 A groove is formed on the side of the retaining ring 2 near the polishing pad 3. The electro-eddy current sensor 51 and the retaining ring 2 are located on both sides of the polishing pad 3 included in the polishing equipment. During the chemical mechanical polishing process of the polishing equipment on the wafer, the metal portion within the ring 2 is maintained perpendicular to the polishing pad 3 and faces the electro-eddy current sensor 51 at least partially.

The signal acquisition unit 702 is used to obtain the output signal of the electric eddy current sensor 51 during the chemical mechanical polishing process of the polishing equipment on the wafer;

A depth determination unit 703 is used to determine the current groove depth of the retaining ring 2 based on the mapping relationship and the output signal;

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 trench depth.

In this embodiment of the present application, the relationship acquisition unit 701 can obtain a mapping relationship between the groove depth of the holding ring 2 and the signal output by the electro-eddy current sensor 51 when the polishing equipment is operating. The signal acquisition unit 702 obtains the output signal of the electro-eddy current sensor 51 during the chemical mechanical polishing process. The depth determination unit 703 determines the current groove depth of the holding ring 2 based on the obtained 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 based on the current groove depth. Therefore, after the polishing equipment has been used for a period of time, even if the groove depth of the holding ring 2 becomes smaller due to wear or other reasons, the current groove depth of the holding 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 of the wafer polished by the polishing equipment at regular intervals, the pressure of the wafer polished by the polishing equipment can be adjusted at regular intervals. The pressure between the edge and the polishing pad 3 is adjusted in this application based on the specific value of the current groove depth. This allows for more precise adjustment timing and amount, reducing the possibility of excessive or insufficient pressure between the wafer edge and the polishing pad 3 during the polishing process. This optimizes the chemical mechanical polishing effect on the wafer edge.

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 elaborated here.

electronic equipment

FIG8 is a schematic block diagram of an electronic device provided in an embodiment of the present application. The specific embodiments of the present application do not limit the specific implementation of the electronic device. As shown in FIG8 , the electronic device may include: a processor 802, a communications interface 804, a memory 806, and a communication bus 808. Among them:

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

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

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.

Specifically, the program 810 may include program codes, which include computer operating instructions.

Processor 802 may be a CPU, an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. The one or more processors included in a smart device may be processors of the same type, such as one or more CPUs, or may be processors of different types, such as one or more CPUs and one or more ASICs.

RISC-V is an open-source instruction set architecture based on the Reduced Instruction Set Architecture (RISC) principles. It can be applied to various fields, including microcontrollers and FPGA chips. Specifically, it has applications in areas such as IoT security, industrial control, mobile phones, and personal computers. Designed with small size, high speed, and low power consumption in mind, it is particularly well-suited for modern computing devices such as warehouse-scale cloud computers, high-end mobile phones, and tiny embedded systems. With the rise of artificial intelligence (AI) and the Internet of Things (AIoT), the RISC-V instruction set architecture is gaining increasing attention and support, and is expected to become the next generation of widely used CPU architecture.

The computer operating instructions in the embodiments of the present application may be computer operating instructions based on the RISC-V instruction set architecture. Accordingly, the processor 802 may be designed based on the RISC-V instruction set. Specifically, the processor chip in the electronic device provided in the embodiments of the present application may be a chip designed using the RISC-V instruction set. This chip may execute executable code based on the configured instructions, thereby implementing the pressure adjustment method in the above-described embodiments.

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, such as at least one disk memory.

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

The specific implementation of each step in program 810 can be found in the corresponding descriptions of the corresponding steps and units in any of the aforementioned pressure adjustment method embodiments and will not be repeated here. Those skilled in the art will clearly understand that for ease and brevity of description, the specific operating processes of the aforementioned devices and modules can be referenced to the corresponding process descriptions in the aforementioned method embodiments and will not be repeated here.

By using the electronic device of the embodiment of the present application, after the polishing device has been used for a period of time, even if the groove depth of the retaining ring 2 becomes smaller due to wear and tear, 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 polishing device at regular intervals, the pressure between the edge of the wafer and the polishing pad 3 can be adjusted at regular intervals. The pressure between the edge of the wafer and the polishing pad 3 is adjusted according to the specific value of the current groove depth. As a result, the timing and amount of 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. Therefore, the effect of chemical mechanical polishing on the edge of the wafer is optimized.

Computer storage media

This application also provides a computer-readable storage medium storing instructions for causing a machine to execute the pressure adjustment method described herein. Specifically, a system or device equipped with a storage medium may be provided. The storage medium stores software program code that implements the functionality of any of the above-described embodiments, and a computer (or CPU or MPU) in the system or device reads and executes the program code stored in the storage medium.

In this case, the program code read from the storage medium can itself implement the functions of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of this application.

Examples of storage media for providing the program code include floppy disks, hard disks, magneto-optical disks, optical disks (e.g., CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, the program code can be downloaded from a server computer via a communications network.

Computer program products

The present application embodiment 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.

It should be noted that, according to the needs of implementation, the various components/steps described in the embodiments of this 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 this application.

The above-described methods according to the embodiments of the present application can be implemented in hardware, firmware, or 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 as computer code that is originally stored in a remote recording medium or a non-temporary machine-readable medium downloaded via a network and is to be stored in a local recording medium, so that the methods described herein can be stored in such software processing on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It will be understood that a computer, processor, 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. When the software or computer code is accessed and executed by the computer, processor, or hardware, the methods described herein are implemented. In addition, when a general-purpose computer accesses the code for implementing the methods shown herein, the execution of the code transforms the general-purpose computer into a special-purpose computer for performing the methods shown herein.

Those skilled in the art will appreciate that the various exemplary units and method steps described in conjunction with the embodiments disclosed herein can be implemented using electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented using hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for specific applications, but such implementations should not be considered beyond the scope of the embodiments of this application.

The above embodiments are only used to illustrate the embodiments of this application and are not intended to limit the embodiments of this application. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the scope of patent protection of the embodiments of this application shall be limited by the scope of the patent application.

1: Carrier head 2: Retaining ring 21: Groove 3: Polishing pad 31: Polished surface 4: Lower pressing member 5: Polishing plate 51: Electromagnetic eddy current sensor 401-404: Steps 700: Pressure adjustment device 701: Relationship acquisition unit 702: Signal acquisition unit 703: Depth determination unit 704: Pressure adjustment unit 802: Processor 804: Communication interface 806: Memory 808: Communication bus 810: Program

To more clearly illustrate the embodiments of this application or the technical solutions in the prior art, the following briefly introduces the diagrams required for use in the embodiments or the prior art descriptions. Obviously, the diagrams described below are only some of the embodiments described in the embodiments of this application. Those skilled in the art can derive other diagrams based on these diagrams. Figure 1 is a cross-sectional view of a prior art polishing apparatus; Figure 2 is a structural diagram of a retaining ring of a prior art polishing apparatus; Figure 3 is a cross-sectional view of a polishing apparatus according to an embodiment of the present application; Figure 4 is a flow chart of a pressure adjustment method according to an embodiment of the present application; Figure 5 is a schematic diagram of signal values corresponding to the same target retaining ring according to an embodiment of the present application; Figure 6 is a schematic diagram of signal values corresponding to different target retaining rings according to an embodiment of the present application; Figure 7 is a schematic diagram of a pressure adjustment device according to an embodiment of the present application; Figure 8 is a schematic block diagram of an electronic device according to an embodiment of the present application.

401~404: Steps

Claims (9)

A pressure adjustment method, comprising: Obtaining a mapping relationship between the groove depth of a retaining ring included in a polishing device and the signal output by an electro-vortex flow sensor when the polishing device is in operation, wherein the polishing device is used to perform chemical mechanical polishing on wafers and includes a polishing pad. The retaining ring includes an annular metal portion located within the retaining ring. The groove of the retaining ring is formed on a side surface of the retaining ring adjacent to the polishing pad. The electro-vortex flow sensor and the retaining ring are located on both sides of the polishing pad. During chemical mechanical polishing of the wafer by the polishing device, the metal portion within the retaining ring is opposite the electro-vortex flow sensor in a direction perpendicular to the polishing pad for at least part of the time. During chemical mechanical polishing of a wafer by the polishing apparatus, an output signal from the electro-eddy current sensor is obtained; Based on the mapping relationship and the output signal, a current trench depth of the retaining ring is determined; Based on the current trench depth, the pressure between the edge of the wafer and the polishing pad is adjusted; Obtaining the output signal of the electro-eddy current detector includes: obtaining a first output signal of the electro-eddy current detector when the polishing device is operating in a first state, and a second output signal of the electro-eddy current detector when the polishing device is operating in a second state, wherein the first state is a state in which the metal portion within the retaining ring is opposite to the electro-eddy current detector in a direction perpendicular to the polishing pad, and the second state is a state in which neither the metal portion within the retaining ring nor the space enclosed by the metal portion is opposite to the electro-eddy current detector in a direction perpendicular to the polishing pad; Determining the current groove depth of the retaining ring based on the mapping relationship and the output signal includes: determining the current groove depth of the retaining ring based on the mapping relationship, the first output signal, and the second output signal. The method of claim 1 further includes: obtaining groove depths of multiple target retaining rings having different groove depths; after the target retaining rings are installed in the polishing apparatus, controlling the polishing apparatus to rotate the polishing pad in the polishing apparatus at least one revolution, and obtaining multiple first signal values output by the electro-eddy current sensor at different times while the polishing apparatus is operating in the first state, and obtaining multiple second signal values output by the electro-eddy current sensor at different times while the polishing apparatus is operating in the second state; determining the mapping relationship based on the multiple first signal values and multiple second signal values obtained after each target retaining ring is installed in the polishing apparatus, and the groove depth of each target retaining ring. The method of claim 2, wherein 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 apparatus, as well as the groove depth of each target retaining ring, comprises: Determining, among the multiple first signal values obtained after the target retaining ring is installed in the polishing apparatus, the average of the first signal values whose difference from the largest first signal value is less than a first threshold as the first target signal value corresponding to the target retaining ring; Determining, among the multiple second signal values obtained after the target retaining ring is installed in the polishing apparatus, the average of at least some of the second signal values or any second signal value as the second target signal value corresponding to the target retaining ring; 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 holding ring, and the groove depth of each target holding ring. The method of claim 1, wherein adjusting the pressure between the edge of the wafer and the polishing pad based on the current groove depth comprises: If the current groove depth is less than an initial groove depth of the retaining ring, increasing the pressure between the edge of the wafer and the polishing pad. The method of claim 1 further comprises: During the process of chemical mechanical polishing of a wafer by the polishing apparatus, determining the thickness of the wafer mounted in the polishing apparatus based on the output signal of the electro-eddy current sensor, and controlling the polishing apparatus to stop operating when the thickness of the wafer is less than a second threshold, wherein the surface of the wafer comprises a metal film layer. A pressure regulating device comprising: A relationship acquisition unit is configured to acquire a mapping relationship between the groove depth of a retaining ring included in a polishing device and a signal output by an electro-vortex flow sensor when the polishing device is in operation. The polishing device is configured to perform chemical mechanical polishing on wafers and includes a polishing pad. The retaining ring includes an annular metal portion located within the retaining ring. The groove of the retaining ring is formed on a side surface of the retaining ring adjacent to the polishing pad. The electro-vortex flow sensor and the retaining ring are located on both sides of the polishing pad. During chemical mechanical polishing of wafers by the polishing device, the metal portion within the retaining ring is opposed to the electro-vortex flow sensor at least partially at a time in a direction perpendicular to the polishing pad. A signal acquisition unit is configured to acquire an output signal from the electro-vortex flow sensor during chemical mechanical polishing of the wafer by the polishing apparatus. Acquiring the output signal from the electro-vortex flow sensor includes acquiring a first output signal from the electro-vortex flow sensor when the polishing apparatus operates in a first state, and a second output signal from the electro-vortex flow sensor when the polishing apparatus operates in a second state. The first state is a state in which the metal portion within the retaining ring faces the electro-vortex flow sensor in a direction perpendicular to the polishing pad, and the second state is a state in which neither the metal portion within the retaining ring nor the space enclosed by the metal portion faces the electro-vortex flow sensor in a direction perpendicular to the polishing pad. A depth determination unit is configured to determine a current trench depth of the retaining ring based on the mapping relationship and the output signal, wherein determining the current trench depth of the retaining ring based on the mapping relationship and the output signal includes determining the current trench depth of the retaining ring based on the mapping relationship, the first output signal, and the second output signal. A pressure adjustment unit is configured to adjust the pressure between the edge of the wafer and the polishing pad based on the current trench depth. 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 configured to store at least one executable instruction, wherein the executable instruction causes the processor to perform an operation corresponding to the method described in any one of claims 1-5. A computer storage medium, wherein a computer program is stored on the computer storage medium, and when the computer program is executed by a processor, the method as described in any one of claims 1 to 5 is implemented. A computer program product, wherein the computer program product comprises computer instructions, wherein the computer instructions instruct a computing device to execute the method as described in any one of claims 1-5.