Substrate polishing method and substrate polishing apparatus

Abstract

The invention relates to a substrate polishing method and a substrate polishing apparatus. A first dressing for dressing a polishing member with a plurality of preset setting dressing conditions is performed, a first cutting rate of the polishing member is measured based on a measured value of a surface height of the polishing member for each setting dressing condition, and the setting dressing conditions and the first cutting rate are stored as correlation data in association with each other. On the basis of the correlation data, a first dressing condition corresponding to the target cutting rate is applied to polish the substrate, and a second cutting rate of the polishing member is measured on the basis of a measured value of the surface height of the polishing member. And acquiring a second finishing condition corresponding to the target cutting rate based on the change of the second cutting rate relative to the target cutting rate and the correlation data, and grinding the substrate by applying the second finishing condition.

Description

Technical Field

[0001] The present invention relates to a substrate polishing method and a substrate polishing device for polishing substrates such as wafers. Background Art

[0002] As one of the methods for flattening the surface of a substrate for a semiconductor device, there is polishing based on a chemical mechanical polishing (CMP) device. The chemical mechanical polishing device has: a polishing component (polishing cloth, polishing pad, etc.), and a holding part (top ring, polishing head, chuck, etc.) for holding a polishing object such as a substrate. In addition, the surface of the polishing object (polished surface) is pressed against the surface of the polishing component, and a polishing liquid (polishing liquid, chemical liquid, slurry, pure water, etc.) is supplied between the polishing component and the polishing object, and the polishing component and the polishing object are moved relative to each other, thereby polishing the surface of the polishing object to be flat.

[0003] As the material of such a grinding part, a foamed resin or a nonwoven fabric with fine concavoconvex formed on the surface is generally used. Such fine concavoconvex acts as a chip groove that effectively prevents clogging and reduces the grinding resistance. However, when the grinding part continues to grind the object, the fine concavoconvex on the surface of the grinding part is crushed, causing a decrease in the grinding rate. Therefore, a dresser that charges a majority of abrasive particles such as diamond particles is used to dress (grind) the surface of the grinding part, and fine concavoconvex is formed again on the surface of the grinding part.

[0004] In the dressing of the grinding part, the rotating dresser is moved in the radial direction of the grinding part while being pressed against the grinding part, so that a small amount of the surface of the grinding part is scraped off. Therefore, if the dressing is not performed properly, inappropriate undulations will occur on the surface of the grinding part, which will cause the deviation of the grinding rate relative to the grinding rate of the substrate on the grinding surface, and it is necessary to perform dressing properly.

[0005] For example, Japanese Patent Gazette No. 2010-162688 describes a dressing method for a polishing pad, which includes a cutting rate measuring means for measuring the cutting rate of a polishing pad by a dresser (the amount of wear of the polishing pad per unit time), and the measured cutting rate of the polishing pad is fed back to a dressing condition based on a dresser drive control means.

[0006] In the above-mentioned patent documentation, there is no record of any cutting rate for the grinding pad measured, specifically how to feed back to the dressing condition. The adjustment of the dressing condition is carried out by adjusting the moving speed (the moving speed in the radial direction of the grinding pad) of the dresser on the grinding pad, but in order to prevent the decline in productivity, it is necessary to keep the total moving time of the dresser constant. Therefore, when improving the moving speed of the dresser at the radial position on the grinding pad, it is necessary to reduce the dresser moving speed at other positions, and it is difficult to properly keep the cutting rate of the grinding pad.

[0007] In addition, when the same dressing conditions are applied to polishing pads of the same specifications, it is ideal that the cutting rates are the same. However, in reality, due to factors such as individual differences in polishing pads, water absorption distribution of polishing pads, and the environment during dressing, the cutting rates of polishing pads may deviate. In addition, due to repeated dressing, the polishing pads and dressers wear, which may cause the cutting rates of polishing pads to deviate. Therefore, considering the deviation in cutting rates, the polishing pads need to be replaced before reaching the specified wear amount. Summary of the invention

[0008] One embodiment of the present invention is a substrate grinding method, which grinds the substrate by bringing a grinding component used in a substrate grinding device into contact with a substrate, and performs a first dressing process of dressing the grinding component according to a plurality of pre-set dressing conditions. For each of the dressing conditions, a first cutting rate of the grinding component is measured based on a measured value of a surface height of the grinding component, and the dressing condition is associated with the first cutting rate and stored as correlation data. The substrate is ground using the first dressing condition corresponding to a target cutting rate, and a second cutting rate of the grinding component is measured based on the measured value of the surface height of the grinding component. The correlation data is corrected based on a change in the second cutting rate relative to the target cutting rate, and a second dressing condition corresponding to the target cutting rate is obtained based on the corrected correlation data, and the substrate is ground using the second dressing condition.

[0009] One embodiment of the present invention is a substrate grinding method, which grinds the substrate by bringing a grinding component used in a substrate grinding device into contact with a substrate, and performs a first dressing process of dressing the grinding component according to a plurality of pre-set dressing conditions. For each of the dressing conditions, a first cutting rate of the grinding component is measured based on a measured value of a surface height of the grinding component, and the dressing condition is associated with the first cutting rate and stored as correlation data. The substrate is ground using the first dressing condition corresponding to a target cutting rate, and a second cutting rate of the grinding component is measured based on the measured value of the surface height of the grinding component. The target cutting rate is changed based on a change in the second cutting rate relative to the target cutting rate, and a second dressing condition is obtained based on the correlation data corresponding to the changed target cutting rate, and the substrate is ground using the second dressing condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram schematically showing the structure of a substrate polishing device.

[0011] Figure 2 It is a top view schematically showing a dresser and a polishing pad.

[0012] Figure 3 This is a diagram showing an example of a scanning area set on a polishing pad.

[0013] Figure 4 This is a block diagram showing an example of functional blocks of a dresser control unit that controls the operation of the dresser.

[0014] Figure 5 This is an explanatory diagram for explaining an example of the dresser deformation amount (wear amount) when the dressing load and the dressing rotation speed are changed.

[0015] Figure 6 This is an explanatory diagram showing an example of the dressing rotation speed and the cutting rate.

[0016] Figure 7 This is an explanatory diagram showing an example of the relationship between the dressing rotation speed and the dressing load corresponding to the target cutting rate.

[0017] Figure 8 This is an explanatory diagram showing an example of changing the dressing conditions.

[0018] Fig. 9 This is a flowchart showing an example of the cutting rate setting process.

[0019] Fig.10 This is a flow chart showing an example of substrate polishing and dressing processing.

[0020] Fig.11 This is a flowchart showing another example of substrate polishing and trimming processing. DETAILED DESCRIPTION

[0021] An embodiment of the present invention will be described with reference to the drawings. Figure 1 1 is a schematic diagram showing a polishing device for polishing a substrate such as a wafer. The polishing device is provided in a substrate processing apparatus capable of performing a series of steps of polishing, cleaning, and drying a substrate W.

[0022] like Figure 1 As shown, the polishing device includes: a polishing unit 10 for polishing a substrate W; a polishing table 12 for holding a polishing pad (polishing component) 11; a polishing liquid supply nozzle 13 for supplying polishing liquid to the polishing pad 11; and a dressing unit 14 for adjusting (dressing) the polishing pad 11 used in polishing the substrate W.

[0023] The polishing unit 10 includes a top ring (substrate holding portion) 20 connected to the lower end of a top ring shaft 21. The top ring 20 is configured to hold the substrate W on its lower surface by vacuum adsorption. The top ring shaft 21 is driven to rotate by a motor (not shown), and the top ring 20 and the substrate W rotate by the rotation of the top ring shaft 21. The top ring shaft 21 moves up and down relative to the polishing pad 11 by a vertical movement mechanism composed of, for example, a servo motor and a ball screw.

[0024] The polishing table 12 is connected to a motor (not shown) disposed below the polishing table 12. The polishing table 12 is rotated around its axis by the motor. The polishing pad 11 is attached to the upper surface of the polishing table 12. The upper surface of the polishing pad 11 forms a polishing surface 11a that contacts the substrate W.

[0025] The polishing of the substrate W is performed as follows. The top ring 20 and the polishing table 12 are rotated respectively, and the polishing liquid is supplied to the polishing pad 11. In this state, the top ring 20 holding the substrate W is lowered, and the substrate W is further pressed against the polishing surface 11a of the polishing pad 11 by a pressurizing mechanism (not shown) composed of an air bag provided in the top ring 20. The substrate W and the polishing pad 11 are in sliding contact with each other in the presence of the polishing liquid, thereby polishing the surface of the substrate W to make it flat.

[0026] The dressing unit 14 includes: a dresser 23 in contact with the polishing pad 11; a dresser shaft 24 connected to the dresser 23; a cylinder 25 provided at the upper end of the dresser shaft 24; and a dresser arm 26 rotatably supporting the dresser shaft 24. Abrasive grains such as diamond particles are fixed to the lower surface of the dresser 23. The lower surface of the dresser 23 constitutes a dressing surface for dressing the polishing pad 11.

[0027] The dresser shaft 24 and the dresser 23 are movable up and down relative to the dresser arm 26. The air cylinder 25 is a device for applying a load (dressing load) to the polishing pad 11 by the dresser 23. The dressing load is adjusted by the air pressure supplied to the air cylinder 25.

[0028] The dresser arm 26 is configured to be driven by a motor 30 and to swing around a support shaft 31. The dresser shaft 24 is rotated by a motor (not shown) provided in the dresser arm 26, and the dresser 23 rotates about its axis by the rotation of the dresser shaft 24. The cylinder 25 presses the dresser 23 against the polishing surface 11a of the polishing pad 11 via the dresser shaft 24 with a predetermined load.

[0029] The dressing of the grinding surface 11a of the grinding pad 11 is performed in the following method. The grinding table 12 and the grinding pad 11 are rotated by a motor, and a dressing liquid (for example, pure water) is supplied to the grinding surface 11a of the grinding pad 11 from a dressing liquid supply nozzle not shown in the figure. Further, the dresser 23 is rotated around its axis. The dresser 23 is pressed against the grinding surface 11a by the cylinder 25, so that the lower surface (dressing surface) of the dresser 23 is in sliding contact with the grinding surface 11a. In this state, the dresser arm 26 is rotated to swing the dresser 23 on the grinding pad 11 in the approximate radial direction of the grinding pad 11. The surface of the grinding pad 11 is cut by the rotating dresser 23.

[0030] A pad height sensor (surface height measuring device) 32 for measuring the height of the grinding surface 11a is fixed to the dresser arm 26. In addition, a sensor target 33 is fixed to the dresser shaft 24 opposite to the pad height sensor 32. The sensor target 33 moves up and down integrally with the dresser shaft 24 and the dresser 23, while the position of the pad height sensor 32 in the up and down direction is fixed. The pad height sensor 32 is a displacement sensor, and by measuring the displacement of the sensor target 33, the height of the grinding surface 11a (the thickness of the grinding pad 11) can be indirectly measured. The sensor target 33 is connected to the dresser 23, so that the pad height sensor 32 can measure the height of the grinding surface 11a during the adjustment of the grinding pad 11. In addition, the pad height sensor 32 may not be a displacement sensor for measuring the displacement of the sensor target 33, but may be a distance sensor for directly measuring the distance to the grinding pad 11.

[0031] The height of the polishing surface 11a is measured by the pad height sensor 32 in a plurality of predetermined areas (monitoring areas M1 to M7) divided in the radial direction of the polishing pad. Figure 3 Reference). The pad height sensor 32 indirectly measures the grinding surface 11a from the position in the up-down direction of the dresser 23 in contact with the grinding surface 11a. Thus, the average height of the grinding surface 11a corresponding to the area (monitoring area) in contact with the lower surface (dressing surface) of the dresser 23 is measured by the pad height sensor 32, and the height of the grinding pad is measured in multiple monitoring areas, thereby obtaining the profile of the grinding pad (the cross-sectional shape of the grinding surface 11a). As the pad height sensor 32, any type of sensor such as a linear scale sensor, a laser sensor, an ultrasonic sensor, or an eddy current sensor can be used.

[0032] The pad height sensor 32 is connected to a dresser control device (control unit) 35, and an output signal of the pad height sensor 32 (i.e., a measured value of the height of the grinding surface 11a) is sent to the dresser control device 35. The dresser control device 35 has the following functions: obtaining a height profile of the grinding pad 11 from the measured value of the height of the grinding surface 11a to calculate the cutting rate of the grinding pad 11, and controlling the dressing conditions (dressing load, rotation speed) of the dresser 23 described later.

[0033] The polishing device includes a table rotary encoder 36 for measuring the rotation angle of the polishing table 12 and the polishing pad 11, and a dresser rotary encoder 37 for measuring the swing angle of the dresser 23. The table rotary encoder 36 and the dresser rotary encoder 37 are absolute encoders for measuring the absolute value of the angle. The rotary encoders 36 and 37 are connected to a dresser control device 35, and the dresser control device 35 obtains the rotation angle of the polishing table 12 and the polishing pad 11 when the height of the polishing surface 11a is measured by the pad height sensor 32, and also obtains information on the swing angle of the dresser 23.

[0034] The dresser shaft 24 connected to the dresser 23 is rotatably supported by the dresser arm 26. The dresser 23 is in contact with the polishing pad 11 through the dresser arm 26. Figure 2 As shown, the polishing pad 11 moves (oscillates) in the radial direction. The dresser unit 14 is electrically connected to a dresser control device 35 that calculates the sliding distance and sliding speed of the dresser 23 .

[0035] Abrasive grains such as diamond particles are fixed to the lower surface of the dresser 23. The portion to which the abrasive grains are fixed constitutes a dressing surface for dressing the grinding surface 11a of the grinding pad 11. As the dressing surface, a circular dressing surface (a dressing surface to which abrasive grains are fixed to the entire lower surface of the dresser 23), an annular dressing surface (a dressing surface to which abrasive grains are fixed to the peripheral portion of the lower surface of the dresser 23), or a plurality of circular dressing surfaces (a dressing surface to which abrasive grains are fixed to the surfaces of a plurality of small-diameter particles arranged at approximately equal intervals around the center of the dresser 23) can be applied. In addition, the dresser 23 of the present embodiment is provided with a circular dressing surface.

[0036] A film thickness sensor (film thickness measuring device) 38 for measuring the film thickness of the substrate W is arranged in the polishing table 12. The film thickness sensor 38 is arranged toward the surface of the substrate W held by the top ring 20. The film thickness sensor 38 is a film thickness measuring device that measures the film thickness of the substrate W while moving across the surface of the substrate W as the polishing table 12 rotates. As the film thickness sensor 38, a non-contact type sensor such as an eddy current sensor and an optical sensor can be applied. The measured value of the film thickness is sent to a control device (not shown) to generate a film thickness profile of the substrate W (film thickness distribution along the radial direction of the substrate W). Based on the film thickness profile, it is determined whether the polishing of the substrate W is completed.

[0037] Figure 2 The figure is used to explain the moving range of the dresser 23. The dresser arm 26 is driven by the motor 30 to rotate clockwise and counterclockwise by a predetermined angle. The dresser 23 moves radially of the polishing pad 11 within the range indicated by the dotted line in the figure by the rotation of the dresser arm 26.

[0038] Figure 3 1 is an explanatory diagram showing the polishing of the substrate W and the dressing of the polishing pad 11 by the dresser 23. The top ring 20 holds the substrate W on the lower surface and rotates in the direction of arrow G around a rotation axis (not shown), thereby rotating the substrate W on the polishing pad 11. The top ring 20 is provided with a retaining ring 39 at its lower end outer periphery, and annular pressure chambers M1 to M4 composed of diaphragms are formed inside the retaining ring 39. By adjusting the pressure of each pressure chamber M1 to M4, the pressing force of the substrate W abutting against the polishing pad 11 can be controlled.

[0039] exist Figure 3 In the embodiment, the dresser 23 is made to contact the polishing table 12 and the polishing pad 11 rotating in the direction of arrow A with a predetermined pressing force while rotating in the direction of arrow C. Figure 2 ) swings, and the dresser 23 dresses the polishing pad 11 while moving along the D direction in the figure (the radial direction of the polishing pad).

[0040] The moving range of the trimmer 23 is divided into a plurality of ( Figure 3 In the example, there are seven scanning areas (swinging intervals) S1 to S7. These scanning areas S1 to S7 are imaginary intervals pre-set on the grinding surface 11a, and are arranged along the moving direction of the dresser 23 (i.e., the approximate radial direction of the grinding pad 11). The dresser 23 dresses the grinding pad 11 while moving across these scanning areas S1 to S7. The lengths of these scanning areas S1 to S7 can be the same as each other, or they can be different. The dresser control device 35 uses the measured values ​​of the height of the grinding pad 11 in each scanning area S1 to S7 measured by the pad height sensor 32 to measure the profile of the grinding amount in the radial direction of the grinding pad 11 (grinding profile).

[0041] The moving speed of the dresser 23 when swinging on the polishing pad 11 is pre-set according to each of the scanning areas S1 to S7, or can be adjusted appropriately. In addition, the pressing force of the dresser 23 on the polishing pad 11 and the rotation speed of the dresser 23 are pre-set or can be adjusted appropriately. By increasing (decreasing) the moving speed of the dresser 23, the residence time of the dresser 23 on the polishing pad 11 becomes shorter (side length), and as a result, the cutting amount of the polishing pad 11 becomes smaller (larger). In addition, as described later, by adjusting the pressing force of the dresser 23 and the rotation speed of the dresser 23, the cutting amount (and cutting rate) of the polishing pad 11 based on the dresser 23 can be adjusted.

[0042] The trimmer control device 35 is a special or general-purpose computer, such as Figure 4 As shown, the dresser control device includes functional blocks such as a dresser driving unit 40, a pad height measuring unit 41, a cutting rate calculating unit 42, a dressing condition setting unit 43, a dressing condition data storage unit 44, and a dressing condition data generating unit 45. The dresser control device controls the operation of the dresser 23 and sets the dressing conditions based on the measured value of the cutting amount (cutting rate) of the polishing pad 11 so that the cutting rate becomes constant.

[0043] The dresser driving unit 40 controls the driving of various motors for driving the dresser 23 , and controls the driving of the dresser 23 under preset conditions (movement speed, dressing load, rotation speed).

[0044] The pad height calculation unit 41 calculates the height of the polishing pad 11 based on the measured value of the pad height sensor 32. The height of the polishing pad 11 calculated by the pad height calculation unit 41 may be calculated for each scanning area S1 to S7, or may be calculated as an average value of the scanning areas S1 to S7. The cutting rate calculation unit 42 calculates the cutting amount (wear amount) of the polishing pad 11 per constant time as the cutting rate based on the change in the height information of the polishing pad calculated by the pad height calculation unit 41.

[0045] The dressing condition setting unit 43 sets the dressing condition (the pressing force and rotation speed of the dresser 23) of the polishing pad 11 by the dresser 23. The dressing condition data storage unit 44 stores information on the cutting rate corresponding to the dressing condition. As described later, the dressing condition data generation unit 45 generates the dressing condition corresponding to the prescribed cutting rate by interpolation or the like, and changes the dressing condition to correct the amount of change when the actual cutting rate changes with the dressing.

[0046] Figure 5 1 is an explanatory diagram showing an example of the deformation amount (wear amount) of the dresser when the dressing load and the dressing speed are changed. Figure 5In (A) to (C), the horizontal axis represents the number of times the dresser 23 moves back and forth (scans) on the polishing pad 11 (dressing scan number), and the amount of cutting (wear) of the polishing pad 11 increases as the number of dressing scans increases. Figure 5 In the description, the case where the number of dressing scans is divided into a plurality of sections (eight sections from 0 to N8) is taken as an example. One section of the number of dressing scans is set so that the amount of polishing pad removed can be measured with high accuracy before and after the section.

[0047] Figure 5 (A) shows an example in which the dressing speed is increased each time the number of dressing scans reaches a certain value (N1 to N4), and this process is repeated twice. Figure 5 (B) shows an example of increasing the dressing load when the number of dressing scans reaches a certain value (N4). In each interval of the number of dressing scans (for example, the interval of the number of dressing scans from 0 to N1), the dressing conditions (based on the pressing force of the dresser 23 and the rotation speed of the dresser 23) are constant. Figure 5 In (A), the value of the dressing rotation speed in each section where the number of dressing scans is 0 to N4 and the value of the dressing rotation speed in each section where the number of dressing scans is N4 to N8 are set to the same value.

[0048] Figure 5 (C) means Figure 5 The graph is an example of the measured values ​​of the deformation amount (the change in the height of the polishing pad 11) of the polishing pad 11 when the polishing is performed under the dressing conditions (based on the pressing force of the dresser 23 and the rotation speed of the dresser 23) in (A) and (B). It shows that as the number of dressing scans increases, the deformation increases and the polishing pad 11 gradually wears out. Figure 5 In the example (C), the deformation amount of the polishing pad 11 was measured for a total of eight dressing conditions, namely, four dressing rotation speeds and two dressing loads.

[0049] The deformation amount in each interval represents the wear amount of the polishing pad when the load and the rotation speed are constant. The dressing conditions in each interval (based on the pressing force and the rotation speed of the dresser 23) are constant, so the cutting rate becomes constant. Here, in each interval with a dressing scan number of 0 to N4 (and each interval with a dressing scan number of N4 to N8), the slope of the deformation amount increases, indicating that the cutting rate increases as the dressing rotation speed increases.

[0050] exist Figure 5In (C), for example, if the interval of dressing scan number N1 to N2 is compared with the interval of N5 to N6, the cutting rate of the grinding pad in the latter is larger. This is because the dressing load is increased in the interval of dressing scan number N5 to N6. In addition, the deformation amount of the grinding pad is discontinuous when the dressing scan number becomes N4 because the deformation amount of the grinding pad 11 increases with the increase of the dressing load. Therefore, when calculating the cutting rate of the grinding pad, this deformation amount needs to be considered.

[0051] Figure 6 is based on Figure 5 Graph of the calculated cutting rate for each dressing condition. Figure 6 The example shows the cutting rate relative to the dressing speed change ( Figure 5 The number of trimming scans is 0 to N4 in each interval). Figure 6 In the table, “low trim load” means the trim load is low ( Figure 5 The number of dressing scans in (B) is in the range of 0 to N4), and "high dressing load" indicates a case where the dressing load is high ( Figure 5 The number of trimming scans of (B) is in the range of N4 to N8). Figure 6 The graph shows that as the dressing speed and the dressing load increase, the cutting rate tends to increase.

[0052] Here, the cutting rate was measured at each point of the dressing rotation speed ( Figure 6 The line connecting the points shown by the circle and triangle ( Figure 6 The curve in ( ) can be calculated by interpolation methods such as spline interpolation. The approximate formulas of the dressing speed and cutting rate associated with these "low dressing load" and "high dressing load" can be a form of data representing the correlation of the cutting rate calculation value with respect to the dressing speed.

[0053] The cutting rate calculation unit 42 changes the dressing load and the dressing speed during the grinding pad running-in or the dresser replacement to perform the dressing process of the grinding pad, calculates the cutting rate based on the measured value of the cutting amount of the grinding pad, establishes the correspondence between the calculated cutting rate data and the dressing load and the dressing speed, and stores them in the dressing condition data storage unit 44. The dressing condition data generation unit 45 calculates the data indicating the correlation between the calculated cutting rate value and the dressing speed and the dressing load, for example, by interpolation, and stores them in the dressing condition data storage unit 44.

[0054] For example, when the dressing process is performed and the cutting rate is calculated using three conditions (10N, 20N, 30N) of dressing loads and four conditions (50rpm, 60rpm, 70rpm, 80rpm) of dressing speeds, data corresponding to twelve conditions are obtained. Using these data, the cutting rate of any condition (e.g., 15N / 65rpm) within the conditions can be calculated by interpolation. The cutting rate data calculated in this way is associated with the data of the corresponding dressing condition and stored in the dressing condition data storage unit 44.

[0055] Here, the grinding of the grinding pad refers to a process of sticking a new grinding pad to a grinding table, and only performing a dressing process (not performing grinding of the substrate) at the beginning. Usually after the grinding, the pad is set to a state most suitable for grinding the substrate by grinding a dummy substrate (dummy grinding). During the grinding period, the substrate (product substrate) is not ground, so there is no influence that is unfavorable to the grinding of the product substrate.

[0056] Figure 7 It is a graph showing an example of the relationship between the dressing conditions corresponding to a certain cutting rate (target cutting rate), and the points on the graph correspond to the same target cutting rate. The dressing condition data generating unit 45 calculates the dressing conditions corresponding to a certain target cutting rate by interpolation or the like based on the data (cutting rate data corresponding to the dressing conditions) stored in the dressing condition data storing unit 44. The dressing condition setting unit 43 sets the dressing conditions corresponding to the target cutting rate by determining the dressing conditions (dressing speed and dressing load) corresponding to any point on the graph. Thus, the grinding of the substrate after the virtual grinding can be started with the dressing conditions that become the target cutting rate, and the grinding process performance can be stabilized by eliminating the individual differences of the dressers.

[0057] Here, even when the dressing conditions are kept constant, the cutting rate of the polishing pad 11 by the dresser 23 changes due to the addition of dressing during polishing. This is because the abrasive grains on the dresser surface become rounded / clogged, and the polishing pad 11 contains moisture. Therefore, even when the setting value of the dressing conditions is kept constant, it is difficult to keep the actual cutting rate of the polishing pad constant.

[0058] Therefore, in this embodiment, the dressing conditions corresponding to the target cutting rate are changed at a constant timing, thereby suppressing the change in cutting rate. In this embodiment, the change rate of the current cutting rate (calculated value) is calculated based on the target cutting rate, and when the change rate exceeds the set value, the dressing conditions (dressing load and dressing rotation number) are set in such a way that the change rate decreases (or becomes zero). Here, the change rate refers to the difference between the cutting rate (for example, a decrease from the initial value due to a change in the dresser) when grinding is performed and dressing is performed under certain dressing conditions and the dressing rate (for example, a decrease from the initial value due to a change in the dresser) according to the change in the dressing condition. Figure 5The data obtained by the method described in the above are the variation rates between the cutting rates that can be obtained under the same dressing conditions.

[0059] In this embodiment, the actual cutting rate is 80% of the target cutting rate (i.e., the actual cutting rate is reduced by 20% as a result of the substrate grinding process and trimming). Figure 5 The dressing condition corresponding to a cutting rate of 125% (=1 / 0.8) of the target cutting rate is calculated by, for example, interpolation from the data related to the dressing condition and the cutting rate obtained by the method described in the above (data stored in the dressing condition data storage unit 44 (data related to the cutting rate corresponding to the dressing condition)). Alternatively, the dressing condition corresponding to a cutting rate of 125% of the target cutting rate may be determined based on an approximate formula of the dressing speed or the dressing load and the cutting rate obtained from the data related to the dressing condition and the cutting rate.

[0060] Alternatively, based on the data related to the dressing conditions and the cutting rate stored in the dressing condition data storage unit 44, a plurality of dressing conditions corresponding to a cutting rate of 125% of the target cutting rate (the changed target cutting rate) are calculated, and based on the calculated plurality of dressing conditions, an approximate formula between the dressing rotation speed and the dressing load is obtained, and the most suitable dressing condition is determined based on the approximate formula. Figure 8 : is a graph showing an example of a method of changing the dressing condition corresponding to the target cutting rate after the change. The change of the dressing condition can be set to the dressing condition ( Figure 8 (1)), or you can just increase the trimming load ( Figure 8 (2)), or you can just increase the dressing speed ( Figure 8 (3)).

[0061] Alternatively, the trimming condition data generating unit 45 may generate the trimming condition data according to the Figure 5 In the data (correlation data) related to the dressing conditions and the cutting rate acquired by the method described above, the obtained cutting rate is multiplied by 0.8 to correct the correlation data. That is, the correlation data is corrected based on the change rate of the calculated cutting rate relative to the target cutting rate, and the dressing conditions for obtaining the target cutting rate are obtained based on the corrected correlation data. When the correlation data is corrected so that the cutting rate becomes 0.8 times, the dressing conditions (dressing load, rotation speed) for obtaining the same cutting rate (target cutting rate) as before the correction are relatively increased.

[0062] During grinding, the dresser (speed or bluntness) changes, so if dressing is performed under the dressing conditions obtained by the above method, the actual cutting rate becomes the target cutting rate (or a value close to the target cutting rate). The parameters of the changed dressing conditions are stored in the dressing condition data storage unit 44, and are changed (or corrected) to the dressing conditions relative to the target cutting rate.

[0063] In addition to the case where the difference between the measured cutting rate and the target value exceeds the specified value, the above-mentioned dressing conditions can also be changed when the number of polishing sheets of the substrate W reaches a specified value, when the wear amount of the polishing pad reaches a specified value, or when a specified time has passed since the last change in dressing conditions, or when the polishing rate of the substrate decreases.

[0064] Fig. 9 1 is a flowchart showing an example of a cutting rate setting process in a grinding device based on the above structure. When the grinding pad or the dresser is replaced (step S11), the dressing condition setting unit 43 changes the dressing condition (dressing load, rotation speed) to a specified value (step S12). Then, the dressing control device 15 makes the dresser 23 move back and forth a specified number of times (dressing scan times) to perform a running-in process of the grinding pad 11 (step S13). After that, the height of the grinding pad 11 is measured by the pad height measuring unit 41, and the cutting rate is calculated by the cutting rate calculation unit 42 (step S14). The information of the calculated cutting rate is stored in the dressing condition data storage unit 44 corresponding to the dressing condition. For all combinations of setting the dressing conditions (dressing load, rotation speed), it is determined whether the cutting rate calculation is performed (step S15). If the calculation is performed (yes), it is transferred to step S16. If the calculation is not performed (no), it returns to step S12 and sets different dressing conditions to calculate the cutting rate.

[0065] In step S16, the dressing condition data generation unit 45 calculates and generates the cutting rate corresponding to other dressing conditions by interpolation or other processing based on the information of the calculated value of the cutting rate for the set dressing conditions (dressing load, rotation speed) stored in the dressing condition data storage unit 44 (step S16). The information of the calculated cutting rate data is stored in the dressing condition data storage unit 44 as relational data in correspondence with the dressing conditions.

[0066] Afterwards, the dressing condition setting unit 43 sets the cutting rate (target cutting rate) of the grinding pad 11 used in the substrate grinding process (step S17), and sets the corresponding dressing conditions (dressing load, rotation speed) based on the cutting rate data stored in the dressing condition data storage unit 44 (step S18).

[0067] In the present embodiment, the target cutting rate is a cutting rate determined in advance, for example, empirically or in consideration of polishing performance or based on productivity of one polishing pad.

[0068] Fig.10 1 is a flowchart showing an example of a process of changing the dressing conditions. When the substrate polishing process starts, the substrate polishing device drives the top ring 20 to polish the substrate W set in the device to a predetermined film thickness. Thereafter, the dresser 23 is driven to dress the polishing pad 11 after the polishing process, thereby grinding the polishing pad 11 (step S21).

[0069] After that, the height of the polishing pad 11 is measured by the pad height measuring unit 41, and the cutting rate is calculated by the cutting rate calculating unit 42 (step S22). In addition, the cutting rate in step S22 can be obtained by measuring the pad height at the end of dressing after grinding, and dividing the pad wear amount by the total dressing time until a certain pad wear amount is reached.

[0070] Afterwards, it is determined whether the difference between the calculated cutting rate and the target cutting rate exceeds the set value. If it exceeds the set value (yes), it is determined that the cutting rate of the polishing pad is reduced by repeated dressing treatment, and the correlation data is corrected in a manner corresponding to the reduction amount from the target cutting rate (step S24). Afterwards, the dressing condition setting unit 43 changes the dressing condition in a manner that the reduction amount becomes zero (while maintaining the value of the target cutting rate) (step S25). In this way, the actual cutting rate can be suppressed from changing from the target cutting rate.

[0071] On the other hand, when the difference between the calculated cutting rate and the target cutting rate is within the set value ("No" in step S22), it is determined that the cutting rate of the polishing pad has not decreased, and the polishing process for the next substrate W is continued without changing the dressing conditions.

[0072] In addition, the target cutting rate may be set to the cutting rate (initial cutting rate) measured in step S14 in correspondence with the predetermined (standard) dressing condition. That is, although the preset value is not set as the target cutting rate, the dressing condition may be corrected in such a way that the initial cutting rate can be obtained even if the dresser is changed during grinding. Thus, the cutting rate can be stabilized during the use of one dresser, and thus the grinding performance can be stabilized.

[0073] In addition, Fig. 9 In the flowchart of FIG. 1 , in step S16, the cutting rates corresponding to other dressing conditions are calculated and generated, and the dressing conditions corresponding to the target cutting rate are set on this basis, but the dressing conditions corresponding to the cutting rates corresponding to the set dressing conditions (step S14) may be set to the cutting rates close to the target cutting rate. In this case, step S16 is omitted.

[0074] Fig.11 This indicates the case where the dressing conditions are changed by changing the target cutting rate. Figure 8 Flow chart of an example of a process for changing the trimming conditions in the embodiment shown in FIG. Fig.10 Step S21 is the same as step S22, so the description is omitted. In step S33, it is determined whether the difference between the calculated cutting rate and the target cutting rate exceeds the set value. In the case of exceeding the set value (yes), it is determined that the cutting rate of the grinding pad is reduced by repeatedly performing the dressing process, and the dressing condition data generating unit 45 changes the target cutting rate in such a way that the reduction amount becomes zero (step S34). Then, the dressing condition setting unit 43 sets the dressing conditions corresponding to the changed target cutting rate (step S35). Thereby, it is possible to suppress the actual cutting rate from varying from the target cutting rate.

[0075] In the above-mentioned embodiment, the method of measuring the cutting rate according to each of the multiple dressing conditions during the running-in process after the new pad is attached to the grinding table is described, but it is not limited to this. It can also be performed in the middle of using the grinding pad while the grinding of the substrate is in progress. It can also be performed on the grinding pad after the use of the grinding pad in the grinding of the substrate is completed. In addition, the process of measuring the cutting rate of each of the multiple dressing conditions and the process of changing the dressing conditions can also be performed separately according to each of the multiple scanning areas of the dresser. In addition, it is not limited to the method of dressing while swinging on the grinding pad. The present invention can also be applied in the method of using a larger diameter dresser in a fixed position in the shape of a grinding pad.

[0076] The above-mentioned embodiments are recorded for the purpose of enabling a person with general knowledge in the technical field to which the present invention belongs to implement the present invention. It is of course possible for a person skilled in the art to implement various variations of the above-mentioned embodiments, and the technical concept of the present invention can also be applied to other embodiments. The present invention is not limited to the described embodiments, and should be interpreted in the broadest sense according to the technical concept defined in the scope of the patent claim.

Claims

1. A substrate polishing method, comprising: bringing a polishing member used in a substrate polishing device into contact with a substrate to polish the substrate, wherein: performing a first dressing process of dressing the grinding member under a plurality of preset dressing conditions, For each set dressing condition, a first cutting rate of the grinding member is measured based on a measured value of the surface height of the grinding member, storing the set dressing condition and the first cutting rate in association with each other as correlation data, polishing the substrate by applying a first dressing condition corresponding to a target cutting rate, and measuring a second cutting rate of the polishing member based on a measured value of a surface height of the polishing member, Based on the change of the second cutting rate relative to the target cutting rate, the correlation data is corrected, and based on the corrected correlation data, a second dressing condition corresponding to the target cutting rate is obtained, The second dressing condition is applied to polish the substrate.

2. The substrate polishing method according to claim 1, wherein: Based on the set dressing condition and the first cutting rate, a cutting rate corresponding to a dressing condition different from the set dressing condition is calculated and stored as correlation data.

3. The substrate polishing method according to claim 1, wherein: The target cutting rate is a predetermined value.

4. The substrate polishing method according to claim 1, wherein: The target cutting rate is a first cutting rate obtained when a first dressing is performed under a predetermined first dressing condition.

5. The substrate polishing method according to claim 1, wherein: The second dressing condition is acquired when the rate of change of the second cutting rate with respect to the target cutting rate exceeds a predetermined value.

6. The substrate polishing method according to claim 1, wherein: The dressing conditions are the rotation speed of the dresser and the dressing load.

7. The substrate polishing method according to claim 6, wherein: The second dressing condition is set by correcting both the rotation speed and the dressing load of the dresser.

8. A substrate polishing method, comprising: bringing a polishing member used in a substrate polishing device into contact with a substrate to polish the substrate, wherein: performing a first dressing process of dressing the grinding member under a plurality of preset dressing conditions, For each set dressing condition, a first cutting rate of the grinding member is measured based on a measured value of the surface height of the grinding member, storing the set dressing condition and the first cutting rate in association with each other as correlation data, polishing the substrate by applying a first dressing condition corresponding to a target cutting rate, and measuring a second cutting rate of the polishing member based on a measured value of a surface height of the polishing member, based on a change in the second cutting rate relative to the target cutting rate, changing the target cutting rate, acquiring a second dressing condition based on the correlation data corresponding to the changed target cutting rate, The second dressing condition is applied to polish the substrate.

9. The substrate polishing method according to claim 8, wherein: Based on the set dressing condition and the first cutting rate, a cutting rate corresponding to a dressing condition different from the set dressing condition is calculated and stored as correlation data.

10. The substrate polishing method according to claim 8, wherein: The target cutting rate is a predetermined value.

11. The substrate polishing method according to claim 8, wherein: The target cutting rate is a first cutting rate obtained when a first dressing is performed under a predetermined first dressing condition.

12. The substrate polishing method according to claim 8, wherein: The second dressing condition is acquired when the rate of change of the second cutting rate with respect to the target cutting rate exceeds a predetermined value.

13. The substrate polishing method according to claim 8, wherein: The dressing conditions are the rotation speed of the dresser and the dressing load.

14. The substrate polishing method according to claim 13, wherein: The second dressing condition is set by correcting both the rotation speed and the dressing load of the dresser.

15. A substrate polishing device for polishing a substrate by making the substrate slide in contact with a polishing member, characterized in that: have: a dresser that performs a first dressing of the grinding component with a plurality of preset dressing conditions; a cutting rate measuring unit that measures a first cutting rate of the grinding member based on a measured value of a surface height of the grinding member for each set dressing condition; a storage unit storing the set dressing condition and the first cutting rate in association with each other as correlation data, a dressing condition setting unit configured to set a dressing condition for the dresser; as well as a dressing condition data generating unit for generating a second dressing condition corresponding to the target cutting rate, grinding a substrate by applying a first dressing condition corresponding to a target cutting rate, measuring a second cutting rate of the grinding component based on a measured value of a surface height of the grinding component, correcting the correlation data based on a change in the second cutting rate relative to the target cutting rate, and generating a second dressing condition corresponding to the target cutting rate based on the corrected correlation data, The second dressing condition is applied to polish the substrate.

16. A substrate polishing device for polishing a substrate by making the substrate slide in contact with a polishing member, characterized in that: have: a dresser that performs a first dressing of the grinding component with a plurality of preset dressing conditions; a cutting rate measuring unit that measures a first cutting rate of the grinding member based on a measured value of a surface height of the grinding member for each set dressing condition; a storage unit storing the set dressing condition and the first cutting rate in association with each other as correlation data, a dressing condition setting unit configured to set a dressing condition for the dresser; as well as a dressing condition data generating unit for generating a second dressing condition corresponding to the target cutting rate, applying a first dressing condition corresponding to a target cutting rate to grind a substrate, measuring a second cutting rate of the grinding member based on a measured value of a surface height of the grinding member, changing the target cutting rate based on a change in the second cutting rate relative to the target cutting rate, and generating a second dressing condition based on the correlation data corresponding to the changed target cutting rate, The second dressing condition is applied to polish the substrate.

Images