Wafer uniformity adjustment method and device, computer device, and storage medium

Abstract

The present application relates to the technical field of chemical mechanical planarization process, and discloses a wafer uniformity adjusting method and device, computer equipment and a storage medium, comprising: performing main grinding test and edge grinding test on the wafer, and recording the main grinding rate and the edge grinding rate of the wafer; based on the main grinding rate and the edge grinding rate, and in combination with the edge grinding time corresponding to the edge grinding test, the comprehensive grinding rate of the test wafer and the uniformity parameter value corresponding to the comprehensive grinding rate are calculated; the minimum value of the uniformity parameter value is taken as the optimal uniformity parameter value, and based on the optimal uniformity parameter value, the optimal grinding condition corresponding to the optimal uniformity parameter value is determined; the wafer is subjected to main grinding, and the wafer is subjected to edge grinding by using the optimal grinding condition. The present application grinds the edge region of the wafer of the same size after main grinding, avoids the occurrence of the thick edge thickness of the ground wafer, meets the demand of the production process, and achieves the optimal effect of wafer planarization.

Description

Technical Field

[0001] This invention relates to the field of chemical mechanical planarization technology, specifically to wafer uniformity adjustment methods, apparatus, computer equipment, and storage media. Background Technology

[0002] With the development of semiconductor chip manufacturing technology, chip sizes are becoming smaller and technology nodes are becoming more advanced, placing increasingly higher demands on the planarization role and requirements of chemical mechanical planarization (CMP) in chip production. The grinding process of a CMP machine involves a grinding head carrying a wafer on a polishing pad. The grinding head applies downward pressure to the wafer, and the grinding head rotates relative to the grinding pad, along with a suitable polishing slurry, to grind the wafer. Currently, mainstream 150mm or 200mm grinding heads control the grinding downward pressure in three zones (RR, Zone 1, Zone 2), applying pressure to the entire wafer surface. The retaining ring zone (RR) is used to fix the wafer and prevent it from scratching the head during grinding; Zone 2 applies downward pressure across the entire wafer surface; and Zone 1 controls the grinding speed at the wafer edges.

[0003] In related technologies, because the polishing head has an air-bag structure, its pressure control over the wafer edge is relatively weak, especially in the outermost 5mm region, resulting in a thicker wafer edge after CMP polishing. This affects subsequent etching or bonding processes. Most existing polishing methods employ a single main polishing step, with the polishing head's three zones having pressures of (x, y, z). The velocity difference between the wafer edge and center can be controlled within 1000A, ideally reaching around 600A, but this still does not meet the requirements of manufacturing processes. Summary of the Invention

[0004] In view of this, the present invention provides a wafer uniformity adjustment method, apparatus, computer equipment and storage medium to solve the problem of excessively thick wafer edges caused by the large speed difference between the wafer edge and the center region due to existing grinding head processing.

[0005] In a first aspect, the present invention provides a method for adjusting wafer uniformity, the method comprising:

[0006] Perform a main grinding test on the test wafer and record the main grinding rate at several points uniformly distributed along the diameter of the test wafer.

[0007] The edge grinding test was performed on the test wafer, and the edge grinding rate of several points evenly distributed on the diameter of the test wafer was recorded.

[0008] Based on the main grinding rate and the edge grinding rate, combined with the edge grinding time corresponding to the edge grinding test, the comprehensive grinding rate of the test wafer and the uniformity parameter value corresponding to the comprehensive grinding rate are calculated.

[0009] The minimum value of the uniformity parameter is selected as the optimal uniformity parameter value. Based on the optimal uniformity parameter value, the optimal grinding conditions corresponding to the optimal uniformity parameter value are determined.

[0010] The wafer to be ground is subjected to primary grinding, and edge grinding is performed on the wafer under optimal grinding conditions. The wafer to be ground has the same dimensions as the test wafer.

[0011] In this invention, by performing full-area main grinding and edge grinding on the wafer, recording the main grinding rate during main grinding and the edge grinding rate during edge grinding, calculating the overall rate and uniformity parameter value, the optimal edge grinding time and optimal edge grinding pressure can be determined. Using the optimal edge grinding time and optimal edge grinding pressure, the edge areas of wafers of the same size are ground after main grinding, realizing automatic adjustment of wafer uniformity, improving the uniformity of wafer grinding, avoiding excessive thickness at the edge of the ground wafer, meeting the requirements of the production process, and achieving the optimal effect of wafer planarization.

[0012] In one alternative implementation, the test wafer includes: a holding ring region, an edge region, and a center region;

[0013] An edge grinding test was performed on the test wafer, and the edge grinding rates at several points uniformly distributed along the diameter of the test wafer were recorded, including:

[0014] A first test pressure is applied to the holding ring region of the test wafer, a second test pressure is applied to the edge region of the test wafer, and a third test pressure is applied to the center region of the test wafer. The first test pressure, the second test pressure, and the third test pressure are considered as a group of edge test pressures, wherein the first test pressure is greater than the second test pressure, and the third test pressure is the lowest pressure that the grinding machine can tolerate.

[0015] Keeping the third test pressure unchanged, set different first and second test pressures to construct several edge test pressure groups;

[0016] Using different edge test pressure groups, edge grinding tests were performed on the test wafer, and the edge grinding rate of each point on the test wafer was recorded under different edge test pressure groups.

[0017] In this method, the rate in the central region of the wafer approaches zero by applying the minimum tolerable pressure of the machine in the central region. A first test pressure is applied to the holding ring region of the wafer, and a second test pressure is applied to the edge region of the test wafer. This is used to collect and record the pressure applied to the edge region to achieve uniformity of wafer grinding. The first test pressure is set to be greater than the second test pressure to prevent the wafer from being thrown out of the grinding table, thus avoiding wafer damage and errors in rate data. By setting different edge test pressure groups, the edge grinding rate of each point of the test wafer under different edge test pressure groups is obtained, which facilitates subsequent wafer uniformity analysis.

[0018] In one optional implementation, based on the main grinding rate and the edge grinding rate, combined with the edge grinding time corresponding to the edge grinding test, the overall grinding rate of the test wafer and the uniformity parameter value corresponding to each set of overall grinding rates are calculated, including:

[0019] Calculate the product of edge grinding rate and edge grinding time, and sum the product with the main grinding rate to obtain the comprehensive grinding rate of each point on the test wafer.

[0020] Calculate the standard deviation and average value of the overall polishing rate at each point on the test wafer, and calculate the quotient of the standard deviation and average value to obtain the uniformity parameter value corresponding to each set of overall polishing rates.

[0021] In this method, the overall grinding rate at each point is calculated, and the uniformity parameter value of each group is further calculated. This makes it easier to determine the optimal uniformity, and then to use the optimal uniformity to determine the optimal grinding conditions in order to achieve wafer planarization.

[0022] In one optional implementation, the calculation of the overall polishing rate of the test wafer and the uniformity parameter value corresponding to each set of overall polishing rates further includes:

[0023] By changing the edge grinding time, calculate and record the overall grinding rate of the test wafer under different edge grinding times and the uniformity parameter value corresponding to each set of overall grinding rates.

[0024] In this method, by calculating the comprehensive grinding rate and corresponding uniformity under different grinding times, the corresponding uniformity parameter values ​​for different grinding times are sorted out, which makes it easier to determine the optimal grinding time for the edge region.

[0025] In one optional implementation, the calculation of the overall polishing rate of the test wafer and the uniformity parameter value corresponding to each set of overall polishing rates further includes:

[0026] Change the edge test pressure group, calculate and record the overall grinding rate of the test wafer under different edge test pressure groups and the uniformity parameter value corresponding to each group of overall grinding rate.

[0027] In this method, by calculating the comprehensive grinding rate and corresponding uniformity under different edge test pressures, the corresponding uniformity parameter values ​​for different edge test pressures are sorted out, which facilitates the determination of the optimal edge grinding pressure for the edge region.

[0028] In one optional implementation, the optimal grinding conditions include: optimal edge grinding pressure and optimal edge grinding time;

[0029] Using optimal grinding conditions, the edges of the wafer to be ground are ground, including:

[0030] The retaining ring region and edge region of the wafer to be ground are ground using the optimal edge grinding pressure and optimal edge grinding time.

[0031] In this method, after the main grinding, an additional step is added to grind the wafer holding ring region and edge region with the optimal edge grinding pressure and the optimal edge grinding time. This achieves automatic adjustment of wafer uniformity, improves the uniformity of wafer grinding, avoids excessive thickness at the edge of the ground wafer, meets the requirements of the production process, and achieves the optimal effect of wafer planarization.

[0032] In a second aspect, the present invention provides a wafer uniformity adjustment device, the device comprising:

[0033] The main grinding test module is used to perform main grinding tests on the test wafer and record the main grinding rate at several points evenly distributed on the diameter of the test wafer.

[0034] The edge grinding test module is used to perform edge grinding tests on the test wafer and record the edge grinding rate of several points evenly distributed on the diameter of the test wafer.

[0035] The uniformity parameter value calculation module is used to calculate the overall grinding rate of the test wafer and the uniformity parameter value corresponding to the overall grinding rate based on the main grinding rate and the edge grinding rate, combined with the edge grinding time corresponding to the edge grinding test.

[0036] The optimal grinding condition determination module is used to select the minimum value of the uniformity parameter as the optimal uniformity parameter value, and based on the optimal uniformity parameter value, determine the optimal grinding conditions corresponding to the optimal uniformity parameter value.

[0037] The wafer grinding module is used to perform main grinding on the wafer to be ground. It uses optimal grinding conditions to perform edge grinding on the wafer to be ground, wherein the size of the wafer to be ground is the same as that of the test wafer.

[0038] Thirdly, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to perform the wafer uniformity adjustment method of the first aspect or any corresponding embodiment described above.

[0039] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions for causing a computer to perform the wafer uniformity adjustment method of the first aspect or any corresponding embodiment described above.

[0040] Fifthly, the present invention provides a computer program product, including computer instructions for causing a computer to execute the wafer uniformity adjustment method of the first aspect or any corresponding embodiment described above. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a schematic flowchart of a wafer uniformity adjustment method according to an embodiment of the present invention.

[0043] Figure 2 This is a schematic diagram of the longitudinal section of a grinding head and a wafer according to an embodiment of the present invention.

[0044] Figure 3 This is a schematic diagram showing the distribution and rate trend of each point in a main grinding step according to an embodiment of the present invention.

[0045] Figure 4 This is a schematic diagram showing the distribution and rate trend of each point in an edge grinding step according to an embodiment of the present invention.

[0046] Figure 5 This is a schematic diagram illustrating the trend of the overall grinding rate of various points on a wafer under different edge grinding times according to an embodiment of the present invention.

[0047] Figure 6 This is a schematic diagram of an optimal edge grinding condition and optimal edge time according to an embodiment of the present invention.

[0048] Figure 7 This is a schematic flowchart of another wafer uniformity adjustment method according to an embodiment of the present invention.

[0049] Figure 8 This is a schematic flowchart of another wafer uniformity adjustment method according to an embodiment of the present invention.

[0050] Figure 9 This is a structural block diagram of a wafer uniformity adjustment device according to an embodiment of the present invention.

[0051] Figure 10 This is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] In related technologies, because the polishing head has an air-bag structure, its pressure control over the wafer edge is relatively weak, especially in the outermost 5mm region, resulting in a thicker wafer edge after CMP polishing. This affects subsequent etching or bonding processes. Most existing polishing methods employ a single main polishing step, with the polishing head's three zones having pressures of (x, y, z). The velocity difference between the wafer edge and center can be controlled within 1000A, ideally reaching around 600A, but this still does not meet the requirements of manufacturing processes.

[0054] To address the aforementioned problems, this invention provides a wafer uniformity adjustment method for use in a computer device. It should be noted that the executing entity can be a wafer uniformity adjustment device, which can be implemented as part or all of the computer device through software, hardware, or a combination of both. The computer device can be a terminal, client, or server. The server can be a single server or a server cluster composed of multiple servers. In this embodiment, the terminal can be a smartphone, personal computer, tablet computer, or other intelligent hardware device. The following method embodiments will use a computer device as the executing entity for illustration.

[0055] The computer equipment in this embodiment is suitable for use in CMP (Chip Polishing) machines for wafer grinding. The wafer uniformity adjustment method provided by this invention performs full-area main grinding and edge grinding on the wafer, records the main grinding rate during main grinding and the edge grinding rate during edge grinding, calculates the overall rate and uniformity parameter values, and thus determines the optimal edge grinding time and pressure for the edge regions. Using the optimal edge grinding time and pressure, the edge regions of wafers of the same size are ground after main grinding, achieving automatic adjustment of wafer uniformity, improving wafer grinding uniformity, avoiding excessive thickness at the wafer edges, meeting the requirements of the production process, and achieving the optimal wafer planarization effect.

[0056] According to an embodiment of the present invention, a wafer uniformity adjustment method is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0057] This embodiment provides a wafer uniformity adjustment method, which can be used in the computer equipment used for grinding control in the aforementioned CMP machine. Figure 1 This is a flowchart of a wafer uniformity adjustment method according to an embodiment of the present invention, such as... Figure 1 As shown, the process includes the following steps:

[0058] Step S101: Perform a main grinding test on the test wafer and record the main grinding rate of several points evenly distributed on the diameter of the test wafer.

[0059] In one example, Figure 2 This is a schematic diagram of a longitudinal section of a grinding head and a wafer according to an embodiment of the present invention, as shown below. Figure 2 As shown, the polishing head is divided into a holding ring region (RR), an edge region (Zone 1), and a full region (Zone 2) to control the polishing pressure applied to the entire wafer. RR is used to fix the wafer and prevent it from slipping out of the polishing head during polishing; Zone 2 applies pressure to the entire wafer; and Zone 1 controls the polishing rate at the wafer's edge. By applying pressure (x, y, z) to the holding ring region (RR), the edge region (Zone 1), and the full region (Zone 2), the main polishing rate data for the main polishing step is obtained. In this invention, 49 uniformly distributed points are set on the wafer diameter as an example; the number of points is not limited in this invention. Figure 3 This is a schematic diagram showing the distribution and rate trend of various points in a main grinding step according to an embodiment of the present invention, as shown below. Figure 3As shown, the horizontal axis represents the distance from the wafer center to the points evenly distributed across the 49 wafer diameters, and the vertical axis represents the main grinding rate RR of the points evenly distributed across the 49 wafer diameters. Main (i), i = 1 to 49.

[0060] Step S102: Perform an edge grinding test on the test wafer and record the edge grinding rate of several points evenly distributed on the diameter of the test wafer.

[0061] In one example, various edge grinding rates were obtained by repeatedly adjusting the pressure applied by the grinding head to the holding ring region (RR) and the edge region (Zone 1). Figure 4 This is a schematic diagram illustrating the distribution and rate trend of each point in an edge grinding step according to an embodiment of the present invention, as shown below. Figure 4 As shown, taking two sets of pressures (a1,b1,c1) and (a2,b2,c2) applied to the holding ring region (RR) and the edge region (Zone1) as examples, the horizontal axis represents the distance of the points uniformly distributed on the 49 wafer diameters from the wafer center, and the vertical axis represents the edge grinding rate RR of the points uniformly distributed on the 49 wafer diameters. Edge-n (i), i = 1 to 49, n = 1, 2, 3..., where n is the number of tests, which is not limited in this scheme.

[0062] Step S103: Based on the main grinding rate and the edge grinding rate, and combined with the edge grinding time corresponding to the edge grinding test, calculate the comprehensive grinding rate of the test wafer and the uniformity parameter value corresponding to the comprehensive grinding rate.

[0063] In one example, the combined grinding rate is calculated under different edge grinding times and different pressures applied by the grinding head to the holding ring region and the edge region, and the uniformity parameter value is obtained by calculating the combined grinding rate. Figure 5 This is a schematic diagram illustrating the trend of the overall grinding rate at various points on a wafer under different edge grinding times according to an embodiment of the present invention, as shown below. Figure 5 As shown, for different edge grinding times, taking time parameters of 1.2, 0.5, and 0.1 as examples, the horizontal axis represents the distance from the wafer center to the points uniformly distributed on the 49 wafer diameters, and the vertical axis represents the combined grinding rate RR(i) obtained by the main grinding and edge grinding of the points uniformly distributed on the 49 wafer diameters. RR(i) = RR Main (i)+K*RR Edge-n (i), where K is the edge grinding time parameter.

[0064] Step S104: Select the minimum value of the uniformity parameter as the optimal uniformity parameter value, and determine the optimal grinding conditions corresponding to the optimal uniformity parameter value based on the optimal uniformity parameter value.

[0065] In one example, the minimum uniformity parameter value is taken as the optimal uniformity parameter value, and the edge grinding time and edge grinding pressure corresponding to the optimal uniformity parameter value are taken as the optimal grinding conditions.

[0066] Step S105: Perform main grinding on the wafer to be ground, and perform edge grinding on the wafer to be ground using the optimal grinding conditions.

[0067] In this embodiment of the invention, the size of the wafer to be ground is the same as that of the test wafer.

[0068] In one example, Figure 6 This is a schematic diagram illustrating an optimal edge grinding condition and optimal edge grinding time according to an embodiment of the present invention, as shown below. Figure 6 As shown, the optimal edge grinding conditions and optimal edge grinding time obtained through the above steps are as follows: In the main grinding step, the main grinding time is 60s, the pressure applied to the guard ring region RR is x Psi, the pressure applied to the edge region Zone1 is y Psi, and the pressure applied to the entire region Zone2 is z Psi; In the edge grinding step, the edge grinding time is 30s, the pressure applied to the guard ring region RR is a2 Psi, the pressure applied to the edge region Zone1 is b2 Psi, and the pressure applied to the entire region Zone2 is c2 Psi. Figure 6 The examples shown are for illustrative purposes only. In this invention, there are no restrictions on the edge grinding conditions or edge grinding time.

[0069] The wafer uniformity adjustment method provided in this embodiment performs full-area main grinding and edge grinding of the wafer, records the main grinding rate during main grinding and the edge grinding rate during edge grinding, calculates the overall rate and uniformity parameter value, and then determines the optimal edge grinding time and optimal edge grinding pressure for the edge region. Using the optimal edge grinding time and optimal edge grinding pressure, the edge region of wafers of the same size is ground after the main grinding, realizing automatic adjustment of wafer uniformity, improving the uniformity of wafer grinding, avoiding excessive thickness at the edge of the ground wafer, meeting the requirements of the production process, and achieving the optimal effect of wafer planarization.

[0070] This embodiment provides a wafer uniformity adjustment method, which can be used in the computer equipment used for grinding control in the aforementioned CMP machine. Figure 7 This is a flowchart of another wafer uniformity adjustment method according to an embodiment of the present invention, such as... Figure 7 As shown, the process includes the following steps:

[0071] Step S701: Perform a main grinding test on the test wafer and record the main grinding rate at several points uniformly distributed along the diameter of the test wafer. For details, please refer to [link to relevant documentation]. Figure 1 Step S101 of the illustrated embodiment will not be described again here.

[0072] Step S702: Perform an edge grinding test on the test wafer and record the edge grinding rate of several points uniformly distributed on the diameter of the test wafer.

[0073] Specifically, the test wafer includes: a holding ring region, an edge region, and a center region; step S702 above includes:

[0074] Step S7021: Apply a first test pressure to the holding ring region of the test wafer, apply a second test pressure to the edge region of the test wafer, and apply a third test pressure to the center region of the test wafer, and combine the first test pressure, the second test pressure and the third test pressure as a group of edge test pressures.

[0075] Step S7022: Keep the third test pressure unchanged, set different first test pressures and second test pressures, and construct several edge test pressure groups.

[0076] Step S7023: Using different edge test pressure groups, perform edge grinding tests on the test wafer and record the edge grinding rate of each point on the test wafer under different edge test pressure groups.

[0077] In this embodiment of the invention, the first test pressure is greater than the second test pressure, and the third test pressure is the lowest pressure that the grinding machine can tolerate.

[0078] In one example, various edge grinding rates are obtained by repeatedly adjusting the pressure applied by the grinding head to the retaining ring region (RR) and the edge region (Zone 1). Taking two sets of pressures (a1, b1, c1) and (a2, b2, c2) applied to the retaining ring region (RR) and the edge region (Zone 1) as examples, c1 and c2 are the lowest tolerable pressures of the grinding machine. The pressures a and b applied to the retaining ring region (RR) and the edge region (Zone 1) can be changed simultaneously or randomly. In this invention, the adjustment method is not limited. It is necessary to maintain pressure a greater than pressure b.

[0079] In this method, the rate in the central region of the wafer approaches zero by applying the minimum tolerable pressure of the machine in the central region. A first test pressure is applied to the holding ring region of the wafer, and a second test pressure is applied to the edge region of the test wafer. This is used to collect and record the pressure applied to the edge region to achieve uniformity of wafer grinding. The first test pressure is set to be greater than the second test pressure to prevent the wafer from being thrown out of the grinding table, thus avoiding wafer damage and errors in rate data. By setting different edge test pressure groups, the edge grinding rate of each point of the test wafer under different edge test pressure groups is obtained, which facilitates subsequent wafer uniformity analysis.

[0080] Step S703: Based on the main grinding rate and the edge grinding rate, and combined with the edge grinding time corresponding to the edge grinding test, calculate the comprehensive grinding rate of the test wafer and the uniformity parameter value corresponding to each group of comprehensive grinding rates.

[0081] Specifically, step S703 includes:

[0082] Step S7031: Calculate the product of edge grinding rate and edge grinding time, and sum the product with the main grinding rate to obtain the comprehensive grinding rate of each point on the test wafer.

[0083] Step S7032: Calculate the standard deviation and average value of the comprehensive grinding rate at each point on the test wafer, and calculate the quotient of the standard deviation and the average value to obtain the uniformity parameter value corresponding to each set of comprehensive grinding rates.

[0084] Step S7033: Change the edge grinding time, calculate and record the overall grinding rate of the test wafer under different edge grinding times and the uniformity parameter value corresponding to each set of overall grinding rates.

[0085] Step S7034: Change the edge test pressure group, calculate and record the comprehensive grinding rate of the test wafer under different edge test pressure groups and the uniformity parameter value corresponding to each comprehensive grinding rate group.

[0086] In one example, using the formula: RR(i) = RR Main (i)+K*RR Edge-n (i), i=1~49, n=1,2,3…, calculate the comprehensive grinding rate RR(i) under different edge grinding times and different pressures applied by the grinding head in the holding ring region and edge region, and obtain multiple sets of comprehensive grinding rates RR(i). Wherein, RR(i) is the comprehensive grinding rate, RR… Main (i) Main grinding rate, RR Edge-n (i) Edge grinding rate, K is a decimal between 0 and 2, used to convert the edge grinding time. k = 1 means edge grinding for 60s, k = 0.5 means edge grinding for 30s.

[0087] The uniformity parameter value NU corresponding to each group of comprehensive grinding rates is calculated using the formula: NU = stdev[RR(i)] / average[RR(i)], i = 1~49. Here, NU is the uniformity parameter value, stdev[] is the standard deviation, and average[] is the average value. Table 1 shows the comprehensive grinding rate and uniformity parameter values ​​under different edge grinding times and different pressures applied by the grinding head to the holding ring region and edge region.

[0088]

[0089] In this method, the overall grinding rate at each point is calculated, and the uniformity parameter value for each group is further calculated. This facilitates the determination of the optimal uniformity, which in turn facilitates the determination of the optimal grinding conditions to achieve wafer planarization. By calculating the overall grinding rate and corresponding uniformity at different grinding times, the corresponding uniformity parameter values ​​for different grinding times are compiled, facilitating the determination of the optimal grinding time for the edge region. By calculating the overall grinding rate and corresponding uniformity at different edge test pressures, the corresponding uniformity parameter values ​​for different edge test pressures are compiled, facilitating the determination of the optimal edge grinding pressure for the edge region.

[0090] Step S704: Select the minimum value of the uniformity parameter as the optimal uniformity parameter value. Based on the optimal uniformity parameter value, determine the optimal grinding conditions corresponding to the optimal uniformity parameter value. For details, please refer to... Figure 1 Step S104 of the illustrated embodiment will not be described again here.

[0091] Step S705: Perform main grinding on the wafer to be ground, using optimal grinding conditions to perform edge grinding on the wafer. For details, please refer to [link to details]. Figure 1 Step S105 of the illustrated embodiment will not be described again here.

[0092] The wafer uniformity adjustment method provided in this embodiment applies a minimum tolerable pressure to the center region of the wafer to bring the grinding rate to near zero. A first test pressure is applied to the holding ring region of the wafer, and a second test pressure is applied to the edge region of the test wafer. This is used to collect and record the pressure applied to the edge region to achieve wafer grinding uniformity. The first test pressure is set to be greater than the second test pressure to prevent the wafer from being thrown off the grinding table, thus avoiding wafer damage and errors in rate data. By setting different edge test pressure groups, the edge grinding rate of each point on the test wafer under different edge test pressure groups is obtained, facilitating subsequent wafer uniformity analysis. By calculating the comprehensive grinding rate at each point, the uniformity parameter value for each group is further calculated, facilitating the determination of the optimal uniformity situation. This, in turn, facilitates the determination of the optimal grinding conditions using the optimal uniformity to achieve wafer planarization. By calculating the comprehensive grinding rate and corresponding uniformity at different grinding times, the corresponding uniformity parameter values ​​for different grinding times are compiled, facilitating the determination of the optimal grinding time for the edge region. By calculating the overall grinding rate and corresponding uniformity under different edge test pressures, and compiling the corresponding uniformity parameter values ​​for different edge test pressures, it is easier to determine the optimal edge grinding pressure for the edge region.

[0093] This embodiment provides a wafer uniformity adjustment method, which can be used in the computer equipment used for grinding control in the aforementioned CMP machine. Figure 8 This is a flowchart of another wafer uniformity adjustment method according to an embodiment of the present invention, such as... Figure 8 As shown, the process includes the following steps:

[0094] Step S801: Perform a main grinding test on the test wafer and record the main grinding rate at several points uniformly distributed along the diameter of the test wafer. For details, please refer to [link to relevant documentation]. Figure 7 Step S701 of the illustrated embodiment will not be described again here.

[0095] Step S802: Perform an edge grinding test on the test wafer and record the edge grinding rate at several points uniformly distributed along the diameter of the test wafer. For details, please refer to [link to relevant documentation]. Figure 7 Step S702 of the illustrated embodiment will not be described again here.

[0096] Step S803: Based on the main grinding rate and the edge grinding rate, combined with the edge grinding time corresponding to the edge grinding test, calculate the overall grinding rate of the test wafer and the uniformity parameter value corresponding to the overall grinding rate. For details, please refer to... Figure 7 Step S703 of the illustrated embodiment will not be described again here.

[0097] Step S804: Select the minimum value of the uniformity parameter as the optimal uniformity parameter value. Based on the optimal uniformity parameter value, determine the optimal grinding conditions corresponding to the optimal uniformity parameter value. For details, please refer to... Figure 7 Step S704 of the illustrated embodiment will not be described again here.

[0098] Step S805: Perform main grinding on the wafer to be ground, and use the optimal grinding conditions to perform edge grinding on the wafer to be ground.

[0099] Specifically, the optimal grinding conditions include: optimal edge grinding pressure and optimal edge grinding time; step S805 above includes:

[0100] Step S8051: Using the optimal edge grinding pressure and optimal edge grinding time, the holding ring region and edge region of the wafer to be ground are ground.

[0101] In one example, during the main grinding step, the main grinding time is 60s, the pressure applied to the guard ring region RR is xPsi, the pressure applied to the edge region Zone1 is yPsi, and the pressure applied to the entire region Zone2 is zPsi; during the edge grinding step, the edge grinding time is 30s, the pressure applied to the guard ring region RR is a2Psi, the pressure applied to the edge region Zone1 is b2Psi, and the pressure applied to the entire region Zone2 is c2Psi.

[0102] In this method, after the main grinding, an additional step is added to grind the wafer holding ring region and edge region with the optimal edge grinding pressure and the optimal edge grinding time. This achieves automatic adjustment of wafer uniformity, improves the uniformity of wafer grinding, avoids excessive thickness at the edge of the ground wafer, meets the requirements of the production process, and achieves the optimal effect of wafer planarization.

[0103] The wafer uniformity adjustment method provided in this embodiment achieves automatic adjustment of wafer uniformity by adding a step after the main grinding to grind the wafer holding ring region and edge region with the optimal edge grinding time using the optimal edge grinding pressure. This improves the uniformity of wafer grinding, avoids excessive thickness at the edge of the ground wafer, meets the requirements of the production process, and achieves the optimal effect of wafer planarization.

[0104] This embodiment also provides a wafer uniformity adjustment device for implementing the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0105] This embodiment provides a wafer uniformity adjustment device, such as... Figure 9 As shown, it includes:

[0106] The main grinding test module 901 is used to perform main grinding tests on the test wafer and record the main grinding rate at several points uniformly distributed along the diameter of the test wafer. For details, please refer to [link to relevant documentation]. Figure 1 Step S101 of the illustrated embodiment will not be described again here.

[0107] The edge grinding test module 902 is used to perform edge grinding tests on the test wafer and record the edge grinding rate at several points uniformly distributed along the diameter of the test wafer. For details, please refer to [link to details]. Figure 1 Step S102 of the illustrated embodiment will not be described again here.

[0108] The uniformity parameter calculation module 903 is used to calculate the overall grinding rate of the test wafer and the corresponding uniformity parameter value based on the main grinding rate and the edge grinding rate, combined with the edge grinding time corresponding to the edge grinding test. For details, please refer to [link to module 903]. Figure 1 Step S103 of the illustrated embodiment will not be described again here.

[0109] The optimal grinding condition determination module 904 is used to select the minimum value of the uniformity parameter as the optimal uniformity parameter value, and based on the optimal uniformity parameter value, determine the optimal grinding conditions corresponding to the optimal uniformity parameter value. For details, please refer to [link to module 904]. Figure 1 Step S104 of the illustrated embodiment will not be described again here.

[0110] The wafer polishing module 905 is used for the main polishing of the wafer to be polished. It utilizes optimal polishing conditions to perform edge polishing on the wafer, whose dimensions are the same as the test wafer. For details, please refer to [link to details]. Figure 1 Step S105 of the illustrated embodiment will not be described again here.

[0111] In some alternative implementations, the test wafer includes: a holding ring region, an edge region, and a center region; the edge grinding test module 902 includes:

[0112] The pressure application unit is used to apply a first test pressure to the holding ring region of the test wafer, a second test pressure to the edge region of the test wafer, and a third test pressure to the center region of the test wafer. The first test pressure, the second test pressure and the third test pressure are used as a group of edge test pressures, wherein the first test pressure is greater than the second test pressure and the third test pressure is the lowest pressure that the grinding machine can tolerate.

[0113] The pressure group construction unit is used to maintain the third test pressure unchanged, set different first test pressures and second test pressures, and construct several edge test pressure groups.

[0114] The edge grinding test unit is used to perform edge grinding tests on the test wafer using different edge test pressure groups, and to record the edge grinding rate of each point on the test wafer under different edge test pressure groups.

[0115] In some optional implementations, the uniformity parameter value calculation module 903 includes:

[0116] The comprehensive grinding rate calculation unit is used to calculate the product of the edge grinding rate and the edge grinding time, and then sum the product with the main grinding rate to obtain the comprehensive grinding rate of each point on the test wafer.

[0117] The uniformity parameter calculation unit is used to calculate the standard deviation and average value of the comprehensive grinding rate at each point of the test wafer, and calculate the quotient of the standard deviation and the average value to obtain the uniformity parameter value corresponding to each set of comprehensive grinding rates.

[0118] In some optional implementations, the uniformity parameter value calculation module 903 further includes:

[0119] The first uniformity parameter value calculation unit is used to change the edge grinding time, calculate and record the overall grinding rate of the test wafer under different edge grinding times and the uniformity parameter value corresponding to each set of overall grinding rates.

[0120] In some optional implementations, the uniformity parameter value calculation module 903 further includes:

[0121] The second uniformity parameter value calculation unit is used to change the edge test pressure group, calculate and record the comprehensive grinding rate of the test wafer under different edge test pressure groups and the uniformity parameter value corresponding to each comprehensive grinding rate group.

[0122] In some optional implementations, the optimal polishing conditions include: optimal edge polishing pressure and optimal edge polishing time; the wafer polishing module 905 includes:

[0123] The wafer grinding unit is used to grind the holding ring area and edge area of ​​the wafer to be ground using optimal edge grinding pressure and optimal edge grinding time.

[0124] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0125] In this embodiment, the wafer uniformity adjustment device is presented in the form of a functional unit. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0126] This invention also provides a computer device having the above-described features. Figure 9 The wafer uniformity adjustment device shown.

[0127] Please see Figure 10 , Figure 10 This is a schematic diagram of the structure of a computer device provided in an optional embodiment of the present invention, such as... Figure 10 As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 10 Take a processor 10 as an example.

[0128] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0129] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0130] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0131] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0132] The computer device also includes an input device 30 and an output device 40. The processor 10, memory 20, input device 30, and output device 40 can be connected via a bus or other means. Figure 10 Taking the example of a connection between China and Israel via a bus.

[0133] Input device 30 can receive input numerical or character information, and generate key signal inputs related to user settings and function control of the computer device, such as a touchscreen, keypad, mouse, trackpad, touchpad, joystick, one or more mouse buttons, trackball, joystick, etc. Output device 40 may include display devices, auxiliary lighting devices (e.g., LEDs), and haptic feedback devices (e.g., vibration motors). The aforementioned display devices include, but are not limited to, liquid crystal displays, light-emitting diodes, displays, and plasma displays. In some alternative embodiments, the display device may be a touchscreen.

[0134] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code, which, when accessed and executed by the computer, processor, or hardware, implements the methods shown in the above embodiments.

[0135] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0136] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for adjusting wafer uniformity, characterized in that, The method includes: A main grinding test is performed on the test wafer, and the main grinding rate of several points uniformly distributed on the diameter of the test wafer is recorded. The test wafer includes: a holding ring region, an edge region, and a center region. An edge grinding test is performed on the test wafer, and the edge grinding rate of several points uniformly distributed along the diameter of the test wafer is recorded, including: A first test pressure is applied to the holding ring region of the test wafer, a second test pressure is applied to the edge region of the test wafer, and a third test pressure is applied to the center region of the test wafer. The first test pressure, the second test pressure, and the third test pressure are considered as a group of edge test pressures, wherein the first test pressure is greater than the second test pressure, and the third test pressure is the lowest pressure that the grinding machine can tolerate. While keeping the third test pressure constant, set different first test pressures and second test pressures to construct several edge test pressure groups; Using different edge test pressure groups, the test wafer is subjected to edge grinding tests, and the edge grinding rate of each point of the test wafer is recorded under different edge test pressure groups; Based on the main grinding rate and the edge grinding rate, and combined with the edge grinding time corresponding to the edge grinding test, the comprehensive grinding rate of the test wafer and the uniformity parameter value corresponding to the comprehensive grinding rate are calculated. The minimum value of the uniformity parameter is selected as the optimal uniformity parameter value, and the optimal grinding conditions corresponding to the optimal uniformity parameter value are determined based on the optimal uniformity parameter value. The wafer to be polished is subjected to main polishing, and the edge polishing of the wafer to be polished is performed using the optimal polishing conditions, wherein the size of the wafer to be polished is the same as that of the test wafer; Specifically, based on the main grinding rate and the edge grinding rate, and combined with the edge grinding time corresponding to the edge grinding test, the comprehensive grinding rate of the test wafer and the uniformity parameter value corresponding to each group of comprehensive grinding rates are calculated, including: Calculate the product of the edge grinding rate and the grinding time, and sum the product with the main grinding rate to obtain the comprehensive grinding rate of each point on the test wafer; Calculate the standard deviation and average value of the overall polishing rate at each point on the test wafer, and calculate the quotient of the standard deviation and average value to obtain the uniformity parameter value corresponding to each set of overall polishing rates.

2. The method according to claim 1, characterized in that, The calculation of the overall polishing rate of the test wafer and the uniformity parameter value corresponding to each group of overall polishing rates also includes: By changing the grinding time, the overall grinding rate of the test wafer under different grinding times and the uniformity parameter value corresponding to each set of overall grinding rates are calculated and recorded.

3. The method according to claim 1, characterized in that, The calculation of the overall polishing rate of the test wafer and the uniformity parameter value corresponding to each group of overall polishing rates also includes: Change the edge test pressure group, calculate and record the overall grinding rate of the test wafer under different edge test pressure groups and the uniformity parameter value corresponding to each group of overall grinding rates.

4. The method according to claim 1, characterized in that, The optimal grinding conditions include: optimal edge grinding pressure and optimal edge grinding time; The process of edge grinding of the wafer to be ground using the optimal grinding conditions includes: The retaining ring region and edge region of the wafer to be ground are ground using the optimal edge grinding pressure and optimal edge grinding time.

5. A wafer uniformity adjustment device, characterized in that, The device includes: The main grinding test module is used to perform main grinding tests on the test wafer and record the main grinding rate of several points evenly distributed on the diameter of the test wafer. The test wafer includes: a holding ring region, an edge region, and a center region. The edge grinding test module is used to perform edge grinding tests on the test wafer and record the edge grinding rates at several points uniformly distributed along the diameter of the test wafer. Specifically, it is used for: A first test pressure is applied to the holding ring region of the test wafer, a second test pressure is applied to the edge region of the test wafer, and a third test pressure is applied to the center region of the test wafer. The first test pressure, the second test pressure, and the third test pressure are considered as a group of edge test pressures, wherein the first test pressure is greater than the second test pressure, and the third test pressure is the lowest pressure that the grinding machine can tolerate. While keeping the third test pressure constant, set different first test pressures and second test pressures to construct several edge test pressure groups; Using different edge test pressure groups, the test wafer is subjected to edge grinding tests, and the edge grinding rate of each point of the test wafer is recorded under different edge test pressure groups; The uniformity parameter value calculation module is used to calculate the overall grinding rate of the test wafer and the uniformity parameter value corresponding to the overall grinding rate based on the main grinding rate and the edge grinding rate, combined with the edge grinding time corresponding to the edge grinding test. The optimal grinding condition determination module is used to select the minimum value of the uniformity parameter as the optimal uniformity parameter value, and determine the optimal grinding conditions corresponding to the optimal uniformity parameter value based on the optimal uniformity parameter value. A wafer grinding module is used to perform main grinding on the wafer to be ground, and to perform edge grinding on the wafer to be ground using the optimal grinding conditions, wherein the size of the wafer to be ground is the same as that of the test wafer; Specifically, the uniformity parameter value calculation module is used for: Calculate the product of the edge grinding rate and the grinding time, and sum the product with the main grinding rate to obtain the comprehensive grinding rate of each point on the test wafer; Calculate the standard deviation and average value of the overall polishing rate at each point on the test wafer, and calculate the quotient of the standard deviation and average value to obtain the uniformity parameter value corresponding to each set of overall polishing rates.

6. A computer device, characterized in that, include: A memory and a processor are communicatively connected, the memory stores computer instructions, and the processor executes the computer instructions to perform the wafer uniformity adjustment method according to any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing a computer to perform the wafer uniformity adjustment method according to any one of claims 1 to 4.

8. A computer program product, characterized in that, Includes computer instructions for causing a computer to perform the wafer uniformity adjustment method according to any one of claims 1 to 4.

Images