Method for synchronously detecting cutting rate of dresser and roughness of polishing pad

Abstract

The invention belongs to the field of wafer manufacturing, and relates to a method for synchronously detecting the cutting rate of a trimmer and the roughness of a polishing pad, which comprises the following steps of: (1) selecting the polishing pad with a groove, and measuring the initial groove depth of the polishing pad by adopting a depth gauge; (2) grinding the polishing pad by using a dresser, stopping the operation at intervals in the grinding process, measuring the groove depth of the polishing pad by using the depth gauge again, and measuring the surface roughness of the polishing pad by using a roughness meter at the same time; and (3) calculating the cutting rate of the dresser according to the groove depth variable quantity of the polishing pad and the corresponding polishing time, and completing synchronous detection of the cutting rate of the dresser and the roughness of the polishing pad. According to the method provided by the invention, synchronous detection of the cutting rate of the trimmer and the roughness of the polishing pad is realized, and a unified delivery inspection standard and a use anomaly analysis basis are provided for the trimmer.

Description

Technical Field

[0001] This invention belongs to the field of wafer manufacturing and relates to a method for simultaneously detecting the cutting rate of a dresser and the roughness of a polishing pad. Background Technology

[0002] Chemical mechanical polishing (CMP) is a key process in semiconductor manufacturing for achieving global wafer planarization, and its polishing accuracy directly determines the integration density and reliability of wafer devices. Diamond disks, as crucial consumables in the CMP process, play a vital role in removing the enamel layer from the polishing pad, restoring surface roughness and trench structure, and ensuring stable polishing rates. Their performance is highly correlated with wafer production yield and efficiency. With the evolution of semiconductor processes towards the nanoscale and ultra-nanoscale, and the application of multi-metal interconnect materials such as copper, cobalt, and ruthenium, the industry has placed stringent demands on the nanoscale morphology control, dynamic cutting stability, and cross-material dressing compatibility of diamond disks.

[0003] However, existing dressers still suffer from numerous technical shortcomings in their fabrication and application, and their performance defects have become a significant factor restricting the improvement of CMP process accuracy. Regarding diamond preparation and arrangement, current processes lack sufficient sorting precision for diamond particles, resulting in natural differences in particle size and shape. Combined with process deviations in coating and sintering, this leads to poor diamond leveling on the dresser disk, with height differences reaching tens of micrometers. In the initial dressing stage, only a few high-quality particles contact the polishing pad, causing uneven polishing pressure distribution, rapid decay of wafer removal rate, and severely impacting planarization consistency. Furthermore, traditional random arrangement methods result in a low proportion of effective cutting particles, poor adaptability to different metal materials, and difficulty in simultaneously meeting the dual requirements of polishing pad groove restoration and surface roughness control.

[0004] Furthermore, at the substrate-interface bonding level, mainstream metal substrates (such as stainless steel) are prone to corrosion in the acidic / alkaline polishing slurry system of CMP, leading to a weakening of the bonding force between diamond and the substrate. The interface layer formed by electroplating or brazing is prone to electrochemical corrosion, accelerating diamond detachment and significantly shortening the lifespan of the dresser. At the same time, controlling the flatness and dimensional tolerance of the substrate processing is difficult, and significant batch-to-batch performance fluctuations occur during mass production, resulting in inconsistent polishing pad wear rates and further affecting the stability of wafer removal rates. In actual dressing processes, detached diamond particles and metal debris easily remain on the polishing pad surface, becoming the main source of defects such as wafer micro-scratches. Advanced processes at 5nm and below have almost zero tolerance for defects, and this type of contamination directly leads to a decrease in wafer yield. If wear debris cannot be removed in time, it can easily clog the micropores and trenches of the polishing pad, causing uneven distribution of the polishing slurry and further reducing polishing efficiency and quality stability.

[0005] More importantly, the semiconductor industry's testing system for dresser performance is currently incomplete. There is a lack of standardized testing methods that can accurately quantify the dresser's cutting rate on the polishing pad, and there are no unified factory inspection indicators or usage anomaly analysis criteria. Existing tests are mostly offline sampling inspections, and can only judge some appearance indicators, making it impossible to predict the cutting uniformity of the dresser in actual use. At the same time, there is no integrated testing method in the industry to simultaneously test the cutting rate and the surface roughness of the polishing pad. In addition, the traditional dresser disassembly and assembly methods are cumbersome and the testing efficiency is low, making it difficult to adapt to the testing needs of industrial mass production.

[0006] It is evident that the performance defects of the aforementioned trimmers and the technological gaps in the testing system together prevent the trimmers from fully playing their role in the CMP process, posing a severe challenge to wafer production yield and cost control, and urgently requiring targeted technical solutions. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for simultaneously detecting the cutting rate of a dresser and the roughness of a polishing pad, thereby enabling simultaneous detection of these two parameters and providing a unified factory inspection standard and a basis for analyzing usage anomalies in dressers.

[0008] To achieve this objective, the present invention adopts the following technical solution: This invention provides a method for simultaneously detecting the cutting rate of a dresser and the roughness of a polishing pad, comprising the following steps: (1) Select a grooved polishing pad and measure the initial groove depth of the polishing pad using a depth gauge; (2) Use a dressing tool to grind the polishing pad, and stop the operation intermittently during the grinding process. Use a depth gauge to measure the groove depth of the polishing pad again, and use a roughness meter to measure the surface roughness of the polishing pad. (3) Calculate the cutting rate of the dresser based on the change in groove depth of the polishing pad and the corresponding polishing time, and complete the synchronous detection of the dresser cutting rate and the roughness of the polishing pad.

[0009] The method provided by this invention enables simultaneous detection of cutting rate and roughness during the polishing process of the dresser, improves the performance consistency of batch processing of the dresser, reduces subsequent additional sorting and inspection procedures, breaks through the current situation in the industry where the two types of indicators are detected separately and the process is fragmented, and to a certain extent balances production efficiency and processing costs, and provides a unified factory inspection standard and a basis for analyzing usage anomalies for the dresser.

[0010] Preferably, the groove type of the polishing pad in step (1) includes cross-shaped grooves and / or concentric circle grooves, and more preferably cross-shaped grooves.

[0011] Preferably, the number of measurement points for the initial trench depth in step (1) is 2 to 20.

[0012] Preferably, the measurement points for the initial groove depth in step (1) are evenly distributed on the surface of the polishing pad.

[0013] Preferably, the polishing fluid used in step (2) includes deionized water.

[0014] Preferably, the liquid supply rate of the grinding process in step (2) is 50~150mL / min.

[0015] Preferably, during the polishing process in step (2), the dressing device applies a pressure of 2 to 15 lbs to the polishing pad.

[0016] Preferably, during the polishing process in step (2), the dressing device rotates and oscillates back and forth along a preset trajectory.

[0017] Preferably, the rotational speed of the trimmer is 50~100rpm, and the reciprocating oscillation stroke range is 60~80mm.

[0018] Preferably, during the polishing process in step (2), the polishing pad is in a rotating state, and the rotation direction of the polishing pad is the same as or opposite to the rotation direction of the dressing tool.

[0019] Preferably, the polishing pad rotates at a speed of 80-150 rpm.

[0020] Preferably, during the polishing process described in step (2), the operation is stopped once every 5 to 15 minutes, and the number of times the operation is stopped is ≥3.

[0021] Preferably, the cutting rate of the dressing device in step (3) is the change in the groove depth of the polishing pad divided by the corresponding polishing time.

[0022] Preferably, the change in groove depth of the polishing pad is the difference between the initial groove depth of the polishing pad and the groove depth after polishing.

[0023] Preferably, the number of dressing devices in step (2) is 2, and the 2 dressing devices are controlled simultaneously to polish the polishing pad.

[0024] Preferably, during the polishing process in step (2), the dresser is simultaneously run-in, and the unbonded particles on the dresser disc are reduced by polishing.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The method provided by this invention enables simultaneous detection of cutting rate and roughness during the polishing process of the dresser, improves the performance consistency of batch processing of the dresser, reduces subsequent additional sorting and inspection procedures, breaks through the current situation in the industry where the two types of indicators are detected separately and the process is fragmented, and to a certain extent balances production efficiency and processing costs, and provides a unified factory inspection standard and a basis for analyzing usage anomalies for the dresser. Attached Figure Description

[0026] Figure 1 This is a top view schematic diagram of the polishing pad with cross-shaped grooves selected in Example 1.

[0027] Figure 2 This is a schematic diagram of the PadCondition control system used in the method provided in Example 1.

[0028] Figure 3 This is a schematic diagram of the detection of the polishing pad surface by the depth gauge and roughness tester in the method provided in Example 1.

[0029] Figure 4 This is a top view schematic diagram of the polishing pad with concentric circular grooves selected in Example 2.

[0030] Figure 5 This is a top view schematic diagram of the polishing pad structure selected in Example 3, which combines cross-shaped grooves and concentric circular grooves.

[0031] Figure 6 This is a schematic diagram of grinding and reducing the diamond particles that are not firmly sintered on the surface of the dressing disc in the methods provided in Examples 1 to 3. Detailed Implementation

[0032] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0033] One embodiment of the present invention provides a method for simultaneously detecting the cutting rate of a dresser and the roughness of a polishing pad, comprising the following steps: (1) Select a grooved polishing pad and measure the initial groove depth of the polishing pad using a depth gauge; (2) Use a dressing tool to grind the polishing pad, and stop the operation intermittently during the grinding process. Use a depth gauge to measure the groove depth of the polishing pad again, and use a roughness meter to measure the surface roughness of the polishing pad. (3) Calculate the cutting rate of the dresser based on the change in groove depth of the polishing pad and the corresponding polishing time, and complete the synchronous detection of the dresser cutting rate and the roughness of the polishing pad.

[0034] The method provided by this invention enables simultaneous detection of cutting rate and roughness during the polishing process of the dresser, improves the performance consistency of batch processing of the dresser, reduces subsequent additional sorting and inspection procedures, breaks through the current situation in the industry where the two types of indicators are detected separately and the process is fragmented, and to a certain extent balances production efficiency and processing costs, and provides a unified factory inspection standard and a basis for analyzing usage anomalies for the dresser.

[0035] In some embodiments, the groove type of the polishing pad in step (1) includes cross-shaped grooves and / or concentric circular grooves, preferably cross-shaped grooves.

[0036] Among them, cross-shaped grooves and concentric circular grooves are the two mainstream polishing pad groove styles in CMP processes, adaptable to the testing needs of different process scenarios, ensuring the versatility and practicality of the testing method. However, compared to concentric circular grooves, cross-shaped grooves can ensure a more uniform distribution of polishing fluid during the testing process, ensuring the stability of the polishing and testing process, and further improving the reliability of the testing results.

[0037] In some embodiments, the number of measurement points for the initial trench depth in step (1) is 2 to 20, for example, 2, 4, 6, 8, 10, 12, 14, 16, 18 or 20, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] This invention allows for the selection of 2 to 20 measurement points to adapt to different detection needs. Fewer points enable rapid initial inspection and improve detection efficiency, while more points enable refined inspection, ensuring the accuracy of initial depth data and balancing detection efficiency and accuracy.

[0039] In some embodiments, the measurement points for the initial trench depth in step (1) are evenly distributed on the surface of the polishing pad.

[0040] Among them, the measurement points evenly distributed on the surface of the polishing pad can avoid the accidental deviation of local point measurement, truly reflect the initial groove depth of the polishing pad as a whole, and provide objective and comprehensive basic data for the comparison of groove depth changes after subsequent grinding and the calculation of cutting rate, which significantly improves the reliability and scientificity of the entire test results.

[0041] In some embodiments, the polishing fluid used in step (2) includes deionized water.

[0042] In some embodiments, the liquid supply rate of the grinding process in step (2) is 50~150 mL / min, for example, it can be 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min, 90 mL / min, 100 mL / min, 110 mL / min, 120 mL / min, 130 mL / min, 140 mL / min or 150 mL / min, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0043] In some embodiments, during the polishing process described in step (2), the dressing applies a pressure of 2 to 15 lbs to the polishing pad, for example, 2 lbs, 3 lbs, 4 lbs, 5 lbs, 6 lbs, 7 lbs, 8 lbs, 9 lbs, 10 lbs, 11 lbs, 12 lbs, 13 lbs, 14 lbs or 15 lbs, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0044] In some embodiments, during the polishing process described in step (2), the dressing device is in a rotating state and oscillates back and forth along a preset trajectory.

[0045] The rotational state provides the basic cutting action for the dresser, avoiding excessive grinding at a single point; the reciprocating oscillation ensures that the dresser's working range covers different areas of the polishing pad, eliminating grinding blind spots, making the overall groove wear and surface roughness changes of the polishing pad more uniform, avoiding local data deviations, and further improving the accuracy of subsequent cutting rate calculations and roughness detection results.

[0046] In some embodiments, the rotational speed of the trimmer is 50-100 rpm, for example, 50 rpm, 55 rpm, 60 rpm, 65 rpm, 70 rpm, 75 rpm, 80 rpm, 85 rpm, 90 rpm, 95 rpm or 100 rpm, and the reciprocating stroke range is 60-80 mm, for example, 60 mm, 62 mm, 64 mm, 66 mm, 68 mm, 70 mm, 72 mm, 74 mm, 76 mm, 78 mm or 80 mm, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0047] In some embodiments, during the polishing process in step (2), the polishing pad is in a rotating state, and the rotation direction of the polishing pad is the same as or opposite to the rotation direction of the dressing tool.

[0048] The method provided by this invention is compatible with both co-rotation and counter-rotation modes of the polishing pad and the dresser, which can be adapted to the actual operating parameters and testing requirements of different semiconductor CMP processes, match diverse process scenarios, and expand the scope of application.

[0049] Furthermore, by adjusting the rotation direction, the contact cutting mode and force distribution between the polishing pad and the dresser can be changed, avoiding local over-polishing or under-polishing of the polishing pad caused by a single rotation direction. This makes the overall groove wear and surface roughness changes of the polishing pad more uniform, reduces local deviations in the detection data, and further improves the accuracy of cutting rate and roughness detection results.

[0050] In some embodiments, the rotational speed of the polishing pad is 80 to 150 rpm, for example, 80 rpm, 85 rpm, 90 rpm, 95 rpm, 100 rpm, 105 rpm, 110 rpm, 115 rpm, 120 rpm, 125 rpm, 130 rpm, 135 rpm, 140 rpm, 145 rpm or 150 rpm, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0051] In some embodiments, during the polishing process described in step (2), the operation is stopped once every 5 to 15 minutes, and the number of times the operation is stopped is ≥3. For example, the interval time can be 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 15 minutes, and the number of times the operation is stopped can be 3, 4, 5, 6, 7, 8, 9 or 10, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0052] This invention limits the number of times to three or more, which can obtain multiple sets of polishing pad groove depth and surface roughness data, avoid the random deviation of a single test, provide a sufficient sample size for cutting rate calculation, and make the test results more referential. Moreover, the interval time can be flexibly adjusted according to actual test needs. Short intervals can accurately capture the dynamic changes of the dresser cutting rate, while long intervals can improve the overall test efficiency and adapt to the test scenarios of different types of dressers.

[0053] In addition, multiple sets of interval test data can intuitively reflect whether the cutting rate of the dresser is uniform during continuous grinding, accurately judge the actual working state of the dresser, and ensure that the test results can not only accurately reflect the cutting rate, but also provide a basis for analyzing the stability of the dresser's use, which is more in line with the actual needs of factory inspection and anomaly analysis.

[0054] In some embodiments, the cutting rate of the dressing device in step (3) is the change in the groove depth of the polishing pad divided by the corresponding polishing time.

[0055] In some embodiments, the change in groove depth of the polishing pad is the difference between the initial groove depth of the polishing pad and the groove depth after polishing.

[0056] In some embodiments, the number of dressing devices in step (2) is two, and the two dressing devices are controlled to grind the polishing pads simultaneously, thereby achieving synchronous detection of the cutting rate of the dual dressing devices and the roughness of the polishing pads.

[0057] In some embodiments, during the polishing process described in step (2), the dresser is simultaneously run-in. The polishing process reduces the particles (such as diamond) that are not firmly sintered on the dresser disk, thereby preventing the particles from falling off during the subsequent CMP process, preventing the clogging of the micropores and grooves of the polishing pad, and further improving the uniformity of the polishing fluid distribution and the consistency of wafer planarization.

[0058] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0059] Example 1 This embodiment provides a method for simultaneously detecting the cutting rate of a dresser and the roughness of a polishing pad, specifically including the following steps: (1) Select a polishing pad with a cross-shaped groove (groove width can accommodate the insertion of a depth gauge probe) (outer diameter 254mm, top view structure see) Figure 1 The initial groove depth of the polishing pad is measured using a depth gauge with an accuracy of 0.01 mm. There are a total of 10 to 20 measurement points for the initial groove depth, which are evenly distributed on the surface of the polishing pad. The arithmetic mean of the initial groove depth of all measurement points is calculated and denoted as D0.

[0060] (2) Install the dresser and polishing pad into the PadCondition control system (see Figure 2 The liquid supply unit is activated, using deionized water as the polishing fluid, with a supply rate set to 100 mL / min. The polishing program is started to use a dresser to polish the polishing pad. During polishing, the dresser applies a pressure of 10 lbs to the polishing pad. The dresser rotates at 80 rpm and oscillates along a preset trajectory with a stroke range of 70 mm. The polishing pad rotates at 120 rpm, with the rotation direction of the polishing pad being the same as that of the dresser. The operation is stopped every 10 minutes, and during the stop, the groove depth of the polishing pad is measured again using a depth gauge (arithmetic mean of 10-20 measurement points) and recorded as D. n (n represents the nth stop of operation, and n = 1, 2, 3…), with a total of 3 stops. Finally, the surface roughness of the polishing pad is measured using a roughness tester and recorded as Ra (see Table 1 below). The table shows the inspection results of the polishing pad surface using a depth gauge and roughness tester. Figure 3.

[0061] (3) Based on the change in groove depth ΔD of the polishing pad n =D n -D n-1 Given a corresponding grinding time Δt = 10 min, calculate the cutting rate F of the dresser within 30 min. n =△D n / △t (see Table 1 below) completes the synchronous detection of the dressinger cutting rate and the polishing pad roughness.

[0062] Example 2 This embodiment provides a method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad, except that the groove type of the polishing pad is changed to concentric circular grooves (see...). Figure 4 The pressure applied by the dressing device to the polishing pad was changed to 5 lbs. The remaining steps and conditions were the same as in Example 1, so they will not be described in detail here.

[0063] Example 3 This embodiment provides a method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad, except that the groove type of the polishing pad is changed to a combination of cross-shaped grooves and concentric circular grooves (see...). Figure 5 The pressure applied by the dressing device to the polishing pad was changed to 15 lbs. The remaining steps and conditions were the same as in Example 1, so they will not be described in detail here.

[0064] Table 1 In addition, during the polishing process in Examples 1-3, the dresser is simultaneously run-in, and the polishing reduces any loosely sintered diamond particles on the dresser's surface (see...). Figure 6 The dashed circle area in the image prevents diamond particles from falling off during subsequent CMP processes, avoids clogging of the polishing pad's micropores and trenches, and further improves the uniformity of polishing fluid distribution and wafer planarization consistency.

[0065] Therefore, the method provided by this invention enables simultaneous detection of cutting rate and roughness during the polishing process of the dressing device, improves the performance consistency of batch processing of the dressing device, reduces subsequent additional sorting and inspection procedures, breaks through the current situation of separate detection of two types of indicators and process fragmentation in the industry, balances production efficiency and processing costs to a certain extent, and provides a unified factory inspection standard and usage anomaly analysis basis for the dressing device.

[0066] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for simultaneously detecting the cutting rate of a dresser and the roughness of a polishing pad, characterized in that, The method includes the following steps: (1) Select a grooved polishing pad and measure the initial groove depth of the polishing pad using a depth gauge; (2) Use a dressing tool to grind the polishing pad, and stop the operation intermittently during the grinding process. Use a depth gauge to measure the groove depth of the polishing pad again, and use a roughness meter to measure the surface roughness of the polishing pad. (3) Calculate the cutting rate of the dresser based on the change in groove depth of the polishing pad and the corresponding polishing time, and complete the synchronous detection of the dresser cutting rate and the roughness of the polishing pad.

2. The method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad according to claim 1, characterized in that, The groove type of the polishing pad in step (1) includes cross-shaped grooves and / or concentric circle grooves, preferably cross-shaped grooves.

3. The method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad according to claim 1, characterized in that, The number of measurement points for the initial trench depth in step (1) is 2 to 20; And / or, the measurement points of the initial trench depth in step (1) are evenly distributed on the surface of the polishing pad.

4. The method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad according to any one of claims 1 to 3, characterized in that, The polishing fluid used in step (2) includes deionized water; And / or, the liquid supply rate for the grinding process in step (2) is 50~150mL / min.

5. The method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad according to any one of claims 1 to 3, characterized in that, During the polishing process described in step (2), the dressing tool applies a pressure of 2 to 15 lbs to the polishing pad; And / or, during the polishing process described in step (2), the dressing device is in a rotating state and swings back and forth along a preset trajectory; The rotational speed of the trimmer is 50~100rpm, and the reciprocating oscillation stroke range is 60~80mm.

6. The method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad according to claim 5, characterized in that, During the polishing process described in step (2), the polishing pad is in a rotating state, and the rotation direction of the polishing pad is the same as or opposite to the rotation direction of the dressing tool; The polishing pad rotates at a speed of 80-150 rpm.

7. The method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad according to any one of claims 1 to 3, characterized in that, During the polishing process described in step (2), the operation is stopped once every 5 to 15 minutes, and the number of times the operation is stopped is ≥3.

8. The method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad according to any one of claims 1 to 3, characterized in that, The cutting rate of the dressing device in step (3) is the change in the groove depth of the polishing pad divided by the corresponding polishing time. The change in groove depth of the polishing pad is the difference between the initial groove depth and the groove depth after polishing.

9. The method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad according to any one of claims 1 to 3, characterized in that, In step (2), there are two dressing devices, and the two dressing devices are controlled simultaneously to polish the polishing pad.

10. The method for simultaneously detecting the cutting rate of the dresser and the roughness of the polishing pad according to any one of claims 1 to 3, characterized in that, During the polishing process described in step (2), the dresser is simultaneously run-in, and the unbonded particles on the dresser disc are reduced by polishing.

Images