Substrate processing apparatus, grinding component finishing method, and recording media

Abstract

The substrate processing apparatus of the present invention, which polishes a substrate by sliding contact with a polishing member, comprises: a trimmer that trims the polishing member by oscillating on the polishing member, and whose oscillation speed is adjustable in a plurality of scanning areas set on the polishing member along the radial direction; a height detection unit that generates a pad profile by measuring the surface height of the polishing member along the radial direction of the polishing member; a trimmer load setting unit that sets the trimmer load imposed on the polishing member by the trimmer; a pad height correction unit that calculates a correction amount for the change in the surface height of the polishing member with respect to a reference load according to the trimmer load throughout the radial direction, and corrects the pad profile by correcting the measured value of the surface height with the correction amount; and a movement speed calculation unit that adjusts the oscillation speed of the trimmer in each scanning area based on the corrected pad profile.

Description

[Technical Field]

[0001] This invention relates to a method for controlling the trimming of a grinding component on a grinding substrate and a substrate processing apparatus. [Previous Technology]

[0002] One method for planarizing the surface of a substrate used to form a semiconductor device is grinding using a chemical mechanical polishing (CMP) apparatus. The CMP apparatus includes: a polishing member (polishing cloth, polishing pad, etc.); and a holding part (upper annular rotating disk, polishing head, chuck, etc.) for holding the object to be polished, such as a substrate. Then, the surface of the object to be polished (the surface to be polished) is pressed against the surface of the polishing member, and a polishing fluid (grinding fluid, reagent, slurry, pure water, etc.) is supplied between the polishing member and the object to be polished. By causing relative movement between the polishing member and the object to be polished, the surface of the object to be polished flat.

[0003] The material of the grinding component is usually foamed resin or non-woven fabric. Micro-uneven surfaces are formed on the surface of the grinding component, which effectively function as chip pockets to prevent clogging and reduce grinding resistance. However, when the grinding component is continuously used to grind the object, the micro-uneven surfaces on the surface of the grinding component wear down, resulting in a decrease in grinding efficiency. Therefore, a dresser using many abrasive particles, such as electrodeposited diamond particles, is used periodically to dress (reshape) the surface of the grinding component, thereby re-forming the micro-uneven surfaces on the surface of the grinding component.

[0004] A dressing method for the grinding component involves moving a rotating dressing device (in an arc or linear reciprocating motion, or oscillation) and pressing the dressing surface against the rotating grinding component for dressing. During dressing, the surface of the grinding component is slightly removed. Therefore, if dressing is not performed appropriately, inappropriate undulations will occur on the surface of the grinding component, resulting in variations in the grinding ratio on the ground surface. Since variations in the grinding ratio are a cause of poor grinding, appropriate dressing is necessary to prevent inappropriate undulations on the surface of the grinding component. Variations in the grinding ratio can be suppressed by adjusting the rotational speed of the grinding component, the rotational speed of the dressing device, and the moving speed of the dressing device (dressing conditions).

[0005] For example, the grinding apparatus described in Japanese Patent Application Publication No. 2014-161944 sets a plurality of swing intervals along the swing direction of the dresser, and calculates the difference between the current profile of the grinding pad obtained from the measurement value of the surface height of the grinding member in each swing interval and the profile of the grinding pad that is the target, and corrects the moving speed of the dresser in each swing interval to eliminate the difference.

[0006] Furthermore, the grinding apparatus described in Japanese Patent Application Publication No. 2020-28955 corrects the measured value of the height of the dressing device (grinding pad height) by calculating the correction amount based on the change in the load (dressing load) applied to the grinding pad during dressing. [Summary of the Invention]

[0007] (The problem that the invention aims to solve)

[0008] When the dressing load is changed (e.g., when the dressing load is increased), the measured value of the grinding pad height decreases because the grinding pad is pressed to that extent. However, the amount of change in the grinding pad height is inconsistent across the entire grinding pad; for example, the amount of height change at the center and the outer perimeter of the grinding pad will differ. Therefore, when the dressing load is changed, the desired height profile cannot be obtained in the radial direction, including the grinding component. (Means of solving the problem)

[0009] One aspect of the present invention is a substrate processing apparatus that grinds a substrate by sliding contact with a grinding member, and includes: a trimmer that trims the grinding member by oscillating on the grinding member, and whose oscillation speed is adjustable in a plurality of scanning areas set on the grinding member along the radial direction; a height detection unit that generates a pad profile by measuring the surface height of the grinding member along the radial direction of the grinding member; a trimmer load setting unit that sets the trimmer load imposed on the grinding member by the trimmer; a pad height correction unit that calculates a correction amount for the change in the surface height of the grinding member with respect to a reference load according to the trimmer load throughout the radial direction, and corrects the pad profile by correcting the measured value of the surface height with the correction amount; and a movement speed calculation unit that adjusts the oscillation speed of the trimmer in each scanning area based on the corrected pad profile.

[0010] One aspect of the present invention involves oscillating a trimmer on a polishing member of a polishing apparatus used on a substrate to trim the polishing member. The trimmer is adjustable in oscillation speed in a plurality of scanning areas set on the polishing member along the oscillation direction. The method includes: a measurement step, which generates a pad profile by measuring the surface height of the polishing member along the radial direction of the polishing member; a trimmer load setting step, which sets the trimmer load imposed on the polishing member by the trimmer; a pad height correction step, which calculates a correction amount for the change in the surface height of the polishing member relative to a reference load based on the trimmer load throughout the radial direction, and corrects the pad profile by correcting the measured value of the surface height with the correction amount; and a movement speed calculation step, which adjusts the oscillation speed of the trimmer in each scanning area based on the corrected pad profile.

Implementation Method

[0012] Figure 1 is a top view showing the overall configuration of the substrate processing apparatus. The substrate processing apparatus 10 is divided into a loading / unloading unit 12, a polishing unit 13, and a cleaning unit 14, which are disposed inside the frame 11. In addition, the substrate processing apparatus 10 is equipped with a device control unit 15 for controlling the operation of substrate transport, polishing, cleaning and other processing.

[0013] The loading / unloading unit 12 includes: a front loading section 20 for loading and storing substrate cassettes containing a plurality of substrates W, a traveling mechanism 21, and a transfer robot 22. The transfer robot 22 has two arms, one above the other, and moves on the traveling mechanism 21 to remove the substrates W placed in the substrate cassettes of the front loading section 20 and deliver them to the grinding section 13. It also performs the action of returning the substrates that have been processed from the cleaning section 14 to the substrate cassettes. The substrates W can typically be circular wafers.

[0014] The polishing section 13 is provided with a plurality of polishing devices 13A to 13D for polishing (planarization) the substrate, and these polishing devices are arranged along the length of the substrate processing apparatus. A first and a second linear conveyor 16 and 17 are provided between the polishing section 13 and the cleaning section 14 as a conveying mechanism for transporting the substrate W. The first linear conveyor 16 can move freely between a first position for receiving the substrate W from the loading / unloading section 12; a second and a third position for transferring the substrate W between the polishing devices 13A and 13B; and a fourth position for delivering the substrate W to the second linear conveyor 17.

[0015] The second linear conveyor 17 is movable between a fifth position for receiving substrate W from the first linear conveyor 16 and a sixth and seventh position for transferring substrate W between the polishing units 13C and 13D. Between these conveyors 16 and 17 is a swing conveyor 23 for conveying substrate W from the fourth and fifth positions to the cleaning unit 14 and from the fourth position to the fifth position.

[0016] The cleaning unit 14 includes: a first substrate cleaning device 30, a second substrate cleaning device 31, a substrate drying device 32, and transfer robots 33 and 34 for transferring substrates between these devices. The substrate W, which has undergone polishing treatment by the polishing unit, is cleaned by the first substrate cleaning device 30 (first cleaning), and then further cleaned by the second substrate cleaning device 31 (processing cleaning). The cleaned substrate is transferred from the second substrate cleaning device 31 to the substrate drying device 32 for spin drying. The dried substrate W is removed by the transfer robot 22 and returned to the substrate cassette loaded in the front loading unit 20.

[0017] As shown in FIG2, each of the grinding devices 13A to 13D provided in the grinding section 13 includes: a grinding unit 40 for grinding the substrate W; and a trimming unit 41 for adjusting (adjusting) the grinding pad 43 used for grinding the substrate W. The grinding unit 40 and the trimming unit 41 are provided on the base 42.

[0018] The polishing unit 40 includes: a polishing pad (polishing component) 43; a polishing table 44 for holding the polishing pad 43; an upper annular turntable (substrate holding part) 45 connected to the lower end of the upper annular turntable shaft 46; and a polishing liquid supply nozzle 47 for supplying polishing liquid to the polishing pad 43.

[0019] The upper annular turntable 45 is configured to hold the substrate W below it by vacuum suction. The upper annular turntable shaft 46 is driven by a motor (not shown) to rotate, thereby rotating the upper annular turntable 45 and the substrate W. The upper annular turntable shaft 46 is connected to a rotatable upper annular turntable support arm 48, which is driven by a motor (not shown) to rotate, and the upper annular turntable 45 moves between a grinding position for grinding the substrate W and a loading / unloading position for loading and unloading the substrate W. In addition, the upper annular turntable 45 can move the polishing pad 43 up and down by an up-and-down movement mechanism (not shown) (e.g., an up-and-down movement mechanism composed of a servo motor and a ball screw).

[0020] The polishing table 44 rotates around its axis by a motor (not shown) disposed below it. A polishing pad 43 is attached to the polishing table 44, and the polishing surface 43a of the polishing substrate W is formed on the surface of the polishing pad 43. The polishing pad 43 is made of, for example, foamed resin or non-woven fabric, and has fine bumps and depressions formed on its surface (polishing surface 43a) to effectively play the role of pores to prevent clogging or reduce polishing resistance.

[0021] The substrate W is polished using the polishing pad 43 as follows: The upper annular turntable 45 and the polishing table 44 are rotated, and polishing slurry is supplied to the polishing pad 43 from the polishing slurry supply nozzle 47. In this state, the upper annular turntable 45 holding the substrate W is lowered, and the substrate W is further pressed against the polishing surface 43a of the polishing pad 43 by a pressurizing mechanism (not shown) consisting of an air bladder provided in the upper annular turntable 45. The substrate W and the polishing pad 43 slide into contact with each other in the presence of polishing slurry, thereby polishing and planarizing the surface of the substrate W.

[0022] A film thickness sensor (film thickness measuring machine) 49 for measuring the film thickness of the substrate W is disposed inside the polishing table 44. The film thickness sensor 49 can be a non-contact sensor such as an eddy current sensor or an optical sensor, and its detection surface is disposed facing the surface of the substrate W held on the upper annular turntable 45. As the polishing table 44 rotates, the film thickness sensor 49 moves through the surface of the substrate W and measures the film thickness of the substrate W. The measured film thickness value is sent to a polishing control unit (not shown) to generate the film thickness profile of the substrate W (film thickness distribution along the radial direction of the substrate W), and the polishing process of the substrate W ends when a specified film thickness value is reached.

[0023] The dressing unit 41 includes: a dresser 51 that contacts the grinding surface 43a of the grinding pad 43; a dresser shaft 53 connected to the dresser 51 via a universal joint 52; an air cylinder 54 located at the upper end of the dresser shaft 53; and a dresser support arm 55 that rotatably supports the dresser shaft 53. Abrasive grains such as diamond particles are fixed below the dresser 51. The lower part of the dresser 51 forms the dressing surface for dressing the grinding surface 43a of the grinding pad 43.

[0024] The shape of the dressing surface can be a circular dressing surface (a dressing surface with abrasive grains fixed on the entire underside of the dresser 51); an annular dressing surface (a dressing surface with abrasive grains fixed on the periphery of the underside of the dresser 51); or a plurality of circular dressing surfaces (a plurality of small-diameter circular discs with abrasive grains fixed on their surfaces, arranged at approximately equal intervals around the center of the dresser 51). In addition, the dresser 51 in this embodiment is provided with a circular dressing surface.

[0025] The dressing shaft 53 and the dressing 51 are configured to move the dressing arm 55 up and down. The air cylinder 54 is a device that applies pressure (dresser load) to the dressing 51 on the grinding pad 43, and the dressing load can be adjusted by adjusting the air pressure supplied to the air cylinder 54 by the dressing control unit 60 described later.

[0026] The dresser arm 55 is configured to be driven by a motor 57 and to swing around a support shaft 56 as a center. The dresser shaft 53 is rotated by a motor (not shown) installed in the dresser arm 55, thereby causing the dresser 51 to rotate around its axis. The air cylinder 54 presses the dresser 51 against the grinding surface 43a with a specified dresser load via the dresser shaft 53. The universal joint 52 is configured to allow the dresser 51 to tilt and to transmit the rotation of the dresser shaft 53 to the dresser 51. In this way, even if the dresser shaft 53 is slightly tilted relative to the surface of the grinding pad 43, the lower surface (dressing surface) of the dresser 51 can still be properly pressed against the grinding pad 43.

[0027] The dressing of the grinding surface 43a is performed as follows. The grinding table 44 and the grinding pad 43 are rotated, and dressing fluid (e.g., pure water) is supplied to the grinding surface 43a of the grinding pad 43 from a dressing fluid supply nozzle (not shown). Further, the dresser 51 is rotated around its axis. The dresser 51 is pressed against the grinding surface 43a by a designated dresser load via an air cylinder 54, causing the dressing surface of the dresser 51 to contact the grinding surface 43a. In this state, the dresser arm 55 is rotated, causing the dresser 51 in contact with the grinding pad 43 to swing in the approximate radial direction of the grinding pad 43. Thereby, the rotating dresser 51 removes the grinding surface 43a of the grinding pad 43, thus re-forming the fine irregularities of the grinding surface 43a.

[0028] A pad height sensor (surface height measuring machine) 58 for measuring the height of the grinding surface 43a is fixed on the dresser arm 55. In addition, a sensor marker 59 is fixed on the dresser shaft 53 opposite to the pad height sensor 58. The sensor marker 59 is configured to move up and down integrally with the dresser shaft 53 and the dresser 51, but the vertical position of the pad height sensor 58 is fixed.

[0029] The pad height sensor 58 is, for example, a displacement sensor, and detects the height of the trimmer 51 connected to the sensor mark 59 by measuring the displacement of the sensor mark 59. Since the trimmer 51 is in contact with the polishing pad 43, the height (thickness of the polishing pad 43) of the polishing surface 43a of the polishing pad 43 during the trimming process can be indirectly measured by measuring the trimmer 51. The pad height sensor 58 can use any type of sensor, such as a linear displacement sensor, a laser sensor, an ultrasonic sensor, or an eddy current sensor.

[0030] When measuring the height of the polishing surface 43a using the pad height sensor 58, the measurement is performed in a plurality of designated areas ("monitoring areas" in FIG. 5) divided in the radial direction of the polishing pad 43. The average height of the polishing surface 43a in the area (designated monitoring area) in contact with the underside (polishing surface) of the dresser shaft 51 is measured by the pad height sensor 58. By measuring the height of the polishing pad 43 in the plurality of monitoring areas, the height profile of the polishing pad 43 (the cross-sectional shape of the height of the polishing surface 43a) can be obtained.

[0031] The pad height sensor 58 is connected to the dresser control unit 60, and the output signal of the pad height sensor 58 (that is, the measured value of the height of the polishing pad 43) is sent to the dresser control unit 60. The dresser control unit 60 has the function of obtaining the outline of the polishing pad 43 from the measured value of the height of the polishing surface 43a, and further determining whether the polishing pad 43 is being dressed correctly.

[0032] The dressing unit 41 further includes: a table rotary encoder 61 for measuring the rotation angle of the grinding table 44 and the grinding pad 43; and a dressing rotary encoder 62 for measuring the rotation angle of the dressing device 51. These table rotary encoders 61 and dressing rotary encoders 62 are absolute encoders that measure the absolute value of the angle and are connected to the dressing device control unit 60. The dressing device control unit 60 can obtain information on the rotation angle of the grinding table 44 and the grinding pad 43, and the rotation angle of the dressing device 51, when the height of the grinding surface 43a is measured by the pad height sensor 58.

[0033] A pad roughness measuring device 63 for measuring the surface roughness of the polishing pad 43 is disposed above the polishing pad 43. The pad roughness measuring device 63 can be a conventional non-contact surface roughness measuring device such as an optical type. The pad roughness measuring device 63 is connected to the dressing control unit 60, and the measured value of the surface roughness of the polishing pad 43 is sent to the dressing control unit 60.

[0034] The trimmer control unit 60 is connected to the device control unit 15. In addition to receiving control signals from the device control unit 15 to trim the polishing pad, it also performs the polishing pad contour control processing described later. The device control unit 15 is connected to an input unit 65 such as a keyboard, microphone, or tablet; and an output unit 66 such as a display or speaker. The control program for controlling the operation of the substrate processing device 10 can be pre-installed on the computer constituting the device control unit 15, or it can be stored in a memory medium such as a CD-ROM or DVD-ROM. Alternatively, it can be installed on the device control unit 15 via the Internet. Furthermore, the device control unit 15 can be installed on the substrate processing device 10, or it can be configured to be connected to the substrate processing device 10 via a network.

[0035] Next, the swing of the dresser 51 will be explained with reference to FIG3. The dresser arm 55 (shown as a straight line for simplicity) rotates clockwise and counterclockwise by a specified angle with point J as the center. The position of point J corresponds to the center position of the support shaft 56 (see FIG2). Then, by rotating the dresser arm 55, the rotation center of the dresser 51 swings in the radial direction of the polishing pad 43 within the range shown by the arc L.

[0036] Figure 4 is a partially enlarged view of the polishing surface 43a of the polishing pad 43. The swing range (swing amplitude L) of the dresser 51 is divided into a plurality of (7 in the example of Figure 4) scanning areas (swing intervals) S1 to S7. These scanning areas S1 to S7 are virtual intervals preset on the polishing surface 43a and are arranged along the swing direction of the dresser 51 (i.e., the radial direction of the polishing pad 43). The center of the dresser 51 moves through these scanning areas S1 to S7, while simultaneously polishing the polishing pad 43. The lengths of these scanning areas S1 to S7 may be the same or different.

[0037] Figure 5 is an explanatory diagram showing the positional relationship between the scanning areas S1 to S7 and the monitoring areas M1 to M10 of the polishing pad 43, and the horizontal axis of the figure represents the distance from the center of the polishing pad 43. This embodiment is based on the example of having 7 scanning areas and 10 monitoring areas; however, these numbers can be appropriately changed. In addition, since it is difficult to control the pad profile in the width area from both ends of the scanning area to the radius of the trimmer 51, a monitoring exclusion width is provided on the inner side (the area R1 to R3 from the center of the pad) and the outer side (the area R4 to R2 from the center of the pad); however, it is not necessary to set the exclusion width.

[0038] The moving speed of the trimmer 51 when it oscillates on the polishing pad 43 can be preset or appropriately adjusted in each scanning area S1 to S7. The moving speed distribution of the trimmer 51 indicates the moving speed of the trimmer 51 in each scanning area S1 to S7.

[0039] The moving speed of the dresser 51 is one of the determining factors of the pad height profile of the grinding pad 43. The cutting rate of the grinding pad 43 represents the amount (thickness) of the grinding pad 43 removed by the dresser 51 per unit time. When the dresser moves at a constant speed, the cutting rate values ​​of each scanning area are different because the thickness of the grinding pad 43 removed in each scanning area is usually different. However, since the pad profile should generally maintain its initial shape, the moving speed is adjusted by reducing the difference in the amount of cutting in each scanning area.

[0040] Here, increasing the moving speed of the dresser 51 means shortening the dwell time of the dresser 51 on the polishing pad 43, that is, reducing the cutting amount of the polishing pad 43. Conversely, decreasing the moving speed of the dresser 51 means increasing the dwell time of the dresser 51 on the polishing pad 43, that is, increasing the cutting amount of the polishing pad 43. Therefore, by increasing the moving speed of the dresser 51 in a certain scanning area, the cutting amount in that scanning area can be reduced; by decreasing the moving speed of the dresser 51 in a certain scanning area, the cutting amount in that scanning area can be increased. This allows adjustment of the overall pad height profile of the polishing pad.

[0041] The trimmer control unit 60 is a general-purpose or dedicated computer device equipped with a control program for trimming the polishing pad 43 and controlling the contour of the polishing pad as described later. This control program can be pre-installed on the computer constituting the trimmer control unit 60, or it can be stored on a memory medium such as a CD-ROM or DVD-ROM. Alternatively, it can be installed on the device control unit 15 via the Internet. Furthermore, the trimmer control unit 60 can also be located on the substrate processing device 10, or it can be connected to the substrate processing device 10 via a network.

[0042] As shown in FIG6, the dressing control unit 60 includes: a dressing model setting unit 71, a basic contour calculation unit 72, a cutting rate calculation unit 73, an evaluation index generation unit 74, a moving speed calculation unit 75, a pad height detection unit 76, a dressing load setting unit 77, a pad height correction unit 78, a correction data memory unit 79, and a setting input unit 80. It obtains the contour of the grinding pad 43 and sets the moving speed of the dressing 51 in the scanning area to the optimal value at a specified time.

[0043] The trimming model setting unit 71 sets a trimming model S for calculating the wear amount of the abrasive pad 43 in the scanning area. The trimming model row S is a real number row and column of m rows and n columns when the number of divisions of the monitoring area is set to m (10 in this embodiment) and the number of divisions of the scanning area is set to n (7 in this embodiment), and is determined by various parameters described later.

[0044] When the scanning speed of the trimmer in each scanning area set on the polishing pad 43 is set to V = [v1, v2, ..., vn], and the width of each scanning area is set to W = [w1, w2, ..., wn], the dwell time of the trimmer (center) in each scanning area is expressed as T = W / V = ​​[w1 / v1, w2 / v2, ..., wn / vn]. At this time, when the pad wear amount in each monitoring area is set to U = [u1, u2, ..., um], the pad wear amount U is calculated by performing a row and column operation of U = ST using the aforementioned trimming model row and column S and the dwell time T in each scanning area.

[0045] When exporting the trimming model row S, for example, considering the elements of 1) cutting rate model, 2) trimmer diameter, and 3) scanning speed control, they can be appropriately combined. Regarding the cutting rate model, it is set based on the premise that each element of the trimming model row S is proportional to the dwell time in the monitoring area or proportional to the scraping distance (moving distance).

[0046] Furthermore, regarding the dresser diameter, the elements of the dressing model row S are set with or without considering the diameter of the dresser 51 (including the entire effective area of ​​the dresser, with the grinding pad wearing at the same cutting rate) or without considering the diameter of the dresser 51 (only considering the cutting rate at the center position of the dresser 51). By considering the dresser diameter, even for a dresser with annularly coated diamond particles, a suitable dressing model can be defined. Regarding the scanning speed control, the elements of the dressing model row S are set according to whether the change in the dresser's moving speed is stepped or ramped. By appropriately combining these parameters, a more realistic cutting amount can be calculated from the dressing model S, and the correct profile expectation value can be obtained.

[0047] The pad height detection unit 76 detects the pad height in each monitored area by corresponding the height data of the polishing pad 43 continuously measured by the pad height sensor 58 with the measurement coordinate data on the polishing pad. The correction of the profile of the pad height (pad height profile) according to the load of the dressing device will be described later.

[0048] The basic profile calculation unit 72 calculates the target profile (basic profile Htg(j)) of the pad height at convergence at a specified timing or at the time when a specified condition is met (T1) (see Figure 7). The basic profile is used to calculate the target cutting amount used by the moving speed calculation unit 75 described later. The basic profile can also be calculated based on the height distribution (Diff(j)) of the grinding pad in the initial state of the pad and the measured pad height, or it can be assigned as a set value. In addition, without setting the basic profile, the target cutting amount for the grinding pad 43 to have a flat shape can also be calculated.

[0049] The basic usage of the target cutting amount displays the pad height profile Hp(j) [j=1,2…m] of each monitored area (T2), and the additionally set target reduction amount Atg at convergence, and calculates it using the following formula: min{Hp(j)}-Atg. Furthermore, the target cutting amount for each monitored area, considering the aforementioned basic profile, can be calculated using the following formula: min{Hp(j)}-Atg+Diff(j).

[0050] The cutting rate calculation unit 73 calculates the cutting rate of the dressing device in each monitored area. For example, the cutting rate can also be calculated from the slope of the change in pad height in each monitored area.

[0051] The evaluation index generation unit 74 optimizes the movement speed of the dresser in each scanning area by calculating and correcting the optimal dwell time (oscillation time) in the scanning area using the evaluation index described later. This evaluation index is based on 1) the deviation from the target cutting amount; 2) the deviation from the dwell time in the reference scheme; and 3) the speed difference between adjacent scanning areas, and is a function of the dwell time T = [w1 / v1, w2 / v2, ..., wn / vn] in each scanning area. Then, by setting the dwell time T in each scanning area to minimize this evaluation index, the movement speed of the dresser is optimized. 1) Deviation from the target cutting amount

[0052] When the target cutting amount of the dressing device is set to U0 = [U01, U02, ..., U0m], the deviation from the target cutting amount is calculated by taking the square of the difference between the pad wear amount U (=ST) in each of the aforementioned monitoring areas (|U-U0|2). Furthermore, the profile of the target cutting amount can be determined at any time after the grinding pad is started, or it can be determined based on a manually set value. 2) Deviation from the dwell time of the reference scheme.

[0053] As shown in Figure 8, by calculating the square of the difference (ΔT) between the dresser's moving speed (reference speed (reference dwell time T0) and the dresser's moving speed (dwell time T) in each scanning area, based on the reference scheme set in each scanning area (ΔT2=|T-T0|2), the deviation from the dwell time in the reference scheme can be calculated. Here, the reference speed is the moving speed estimated to obtain a flat cutting rate in each scanning area, and is a value obtained in advance through experiments or simulations. When the reference speed is calculated by simulation, for example, it can be found that the dresser's scraping distance (dwell time) is proportional to the cutting amount of the grinding pad. In addition, the reference speed can be appropriately updated according to the actual cutting rate when using the same grinding pad. 3) Speed ​​difference between adjacent scanning areas

[0054] The polishing apparatus of this embodiment further suppresses the influence of rapid changes in moving speed on the polishing apparatus by suppressing the speed difference between adjacent scanning areas. That is, by calculating the square value of the speed difference between adjacent scanning areas (|ΔVinv|²), the index of the speed difference between adjacent scanning areas can be calculated. Here, as shown in FIG8, the speed difference between scanning areas can be the difference of reference speed (Δinv) or the moving speed of the trimmer (Δv). In addition, since the width of the scanning area is a fixed value, the index of the speed difference depends on the dwell time of the trimmer in each scanning area.

[0055] The evaluation index creation unit 74 defines the evaluation index J as shown in the following formula based on these three indicators. J = γ|U-U0|2+λ|T-T0|2+η|ΔVinv|2 Here, the first, second and third terms on the right side of the evaluation index J are respectively caused by the deviation from the target cutting amount, the deviation from the dwell time of the reference scheme, and the speed difference between adjacent scanning areas, and all depend on the dwell time T of the dresser in each scanning area.

[0056] Then, the moving speed calculation unit 75 performs an optimization calculation to minimize the value of the evaluation index J, and calculates the dwell time T of the trimmer in each scanning area to correct the moving speed of the trimmer. The optimization calculation method can use a quadratic calculation method, but it can also use convergence calculation by simulation or PID control.

[0057] In the above evaluation index J, γ, λ and η are specified weighted values ​​and can be appropriately changed during the use of the same polishing pad. By changing these weighted values, the indicators that need to be emphasized can be appropriately adjusted according to the characteristics of the polishing pad or dressing tool or the operating condition of the device.

[0058] Furthermore, when determining the moving speed of the trimmer, the total trimming time should be kept within a specified value. Here, the total trimming time refers to the moving time of the trimmer across its entire swing range (scanning areas S1 to S7 in this embodiment). Because an extended total trimming time (the time required for trimming) may affect other processes such as the substrate polishing or transport processes, the moving speed in each scanning area should be appropriately adjusted so that this value does not exceed a specified value. In addition, because the device has mechanical limitations, the moving speed of the trimmer should still be set within a set value for the maximum (and minimum) moving speed of the trimmer and the ratio of the maximum speed (minimum speed) to the initial speed.

[0059] Furthermore, when a new dresser and grinding pad are combined and the appropriate dressing conditions are unclear, or when the dresser or grinding pad has been replaced and the reference speed (reference dwell time T0) of the dresser has not yet been determined, the moving speed calculation unit 75 can also use only the deviation condition from the target cutting amount to determine the evaluation index J (described below), thereby optimizing the moving speed of the dresser in each scanning area (initial setting). J = |U - U0|2

[0060] The dresser load setting unit 77 sets the load (dresser load) applied from the dresser 51 to the grinding surface 43a of the grinding pad 43, and adjusts the dresser load on the grinding pad 43 by changing the position of the air cylinder 54. When the dresser load changes from the reference value (reference dresser load), the amount of pressure applied to the grinding pad 43 by the dresser 51 changes. For example, when the dresser load increases, the height of the grinding pad 43 decreases because the grinding pad 43 is pressed further. Conversely, when the dresser load decreases, the height of the grinding pad 43 increases. As a result, due to the change in the position of the grinding surface 43a, the height (wear) of the grinding pad 43 cannot be calculated.

[0061] The pad height correction unit 78 calculates a pad height correction value corresponding to the change in pad height caused by the change in the load of the dresser in order to eliminate the change in pad height caused by the change in the load of the dresser. Since the change in pad height varies depending on the position of the grinding pad 43 in the radial direction, it is configured to calculate a plurality of pad height correction values ​​based on the position of the grinding pad 43 in the radial direction.

[0062] Figure 9 is an example curve showing the distribution of the polishing pad height when the wearer load changes. The horizontal axis represents the radial position of the polishing pad, and the point where it intersects the vertical axis indicates a radius position of zero (the center of the polishing pad). Furthermore, the pad height shows the relative height to a predetermined reference value; a larger value indicates a higher polishing surface 43a of the polishing pad 43. The curve in Figure 9 shows that as the wearer load increases, the pad height decreases. Additionally, the larger the radius position (closer to the outer periphery of the polishing pad 43), the lower the pad height. This pad height data was measured by pre-testing at multiple radius positions (the example in Figure 9 shows 7 points from 50mm to 350mm from the center of the polishing pad) for each wearer load, and is stored in the correction data memory unit 79 as reference data for pad height at different loads / radii.

[0063] The measurement of pad height with different loads / radii can be performed statically (with the grinding table 44 and dresser 51 stopped) or dynamically (with the grinding table 44 and dresser 51 rotated and the dresser 51 oscillating, in a state of actual approach to the dressing of the grinding pad 43). During dynamic measurement, it is preferable to continuously obtain data at multiple radius positions. Furthermore, the load and radius positions are not limited to the examples described above and can be appropriately changed, as long as they are close to the actual usage range; however, the load and radius positions should each have at least three points.

[0064] The calculation of the pad height correction amount in the pad height correction unit 78 can be performed as follows: When the adjuster load set in the adjuster load setting unit 77 is DFx, two adjuster loads (DF1, DF2) close to DFx and the pad height reference data (PadH1, PadH2) corresponding to the adjuster load are read from the pad height reference data of different loads / radii stored in the correction data memory unit 79, and the pad height PadHx for the set adjuster load DFx is calculated by interpolation using the following formula.

[0065] PadHx=(PadH1-PadH2) / (DF1-DF2)×(DFx-DF2)+PadH2, but DF1<DFx<DF2

[0066] In addition to the linear interpolation mentioned above, the interpolation formula can also be obtained by spline interpolation, for example.

[0067] For example, as shown in Figure 9, for every 10N dresser load, the reference data for pad height at different loads / radii is stored in the correction data memory unit 79. When DFx is set to 15N, DF1 is 10N and DF2 is 20N. Therefore, the pad height reference data corresponding to dresser loads of 10N and 20N are read from the correction data memory unit 79, and the pad height Hx at the radius position of each polishing pad is calculated. The pad height correction unit 78 calculates the pad height PadHx calculated by the above formula at each polishing pad radius position for both the specified reference load and the dresser load used for actual dressing (measured load). The calculated pad height PadHx value is stored in the correction data memory unit 79.

[0068] The graph in Figure 10 arranges the pad height values ​​calculated by interpolation along the radius of the grinding pad, and displays the pad height PadHbDF under the reference load (e.g., 25N) and the pad height PadHmDF under the measured load (e.g., 15N). Here, since the reference load and the measured load are independent and mostly constant, they can be pre-calculated and stored in the correction data memory unit 79. This shortens the pad height correction process.

[0069] The pad height correction unit 78 calculates the correction amount PadHdelta(r) for transforming the pad height PadHmDF(r) of the measured load into the reference load PadHbDF(r) for each radius position of the grinding pad using the following formula: PadHdelta(r) = PadHmDF(r) - PadHbDF(r). Next, the pad height correction unit 78 performs interpolation processing on the correction amount value obtained from each radius position to generate a function F(DF, r) of the correction amount for the radius position of the grinding pad.

[0070] Figure 11 is an example curve of the correction function F(DF, r). Each point represents a discrete value of the correction PadHdelta(r) calculated by the above formula (for example, 7 points every 50 mm to 350 mm from the center of the grinding pad). The curve represents an example of the function F obtained by spline interpolation based on the discrete values, and the straight line represents an example of the function F obtained by linear interpolation from adjacent discrete values. When obtaining the function F, an appropriate difference formula can be used. However, when the difference between adjacent discrete values ​​is large, it is advisable to obtain the function F by linear interpolation.

[0071] Here, the formula for calculating the pad height measurement data and correction value should be made according to the type (hardness) of the polishing pad used for dressing. In addition, it can also be made for each combination of polishing pad and dressing device. Furthermore, the formula for calculating the pad height measurement data and correction value can also be set inherently in the polishing table.

[0072] The pad height correction unit 78 uses the function F(DF, r) obtained as described above to calculate the pad height for pad control (and then set as the pad height for the reference load) PadH(r) from the height (measured height) PadHmeasure(r) of the grinding pad measured at a certain radius position, using the following formula: PadH(r) = PadHmeasure(r) + PadHdelta(r)

[0073] The setting input unit 80 is, for example, an input device such as a keyboard and mouse, and inputs the values ​​of each component of the dressing model row S, the setting of the constraint conditions, the cutting rate update cycle, and various parameters such as the travel speed update cycle. In addition, the program data constituting the operation of each component of the dressing control unit 60, the values ​​of each component of the dressing model row S, the target outline, the weighted value of the evaluation index J, and the setting value of the travel speed of the dressing are stored in a non-illustrated memory provided in the dressing control unit 60.

[0074] Figure 12 is a flowchart showing the procedure for grinding and cleaning multiple substrates W and controlling the movement speed of the trimmer after replacing the grinding pad. When the device control unit 15 detects that the grinding pad 43 has been replaced (step S10) by resetting the pad usage time, the trimming model setting unit 71 considers the cutting rate model, trimmer diameter, and scanning speed control parameters, and derives the trimming model row S (step S11). In addition, if the grinding pads 43 before and after replacement are of the same type, the same trimming model row can continue to be used.

[0075] Next, it is determined whether to calculate the reference speed of the dresser (for example, whether to input the purpose of calculating the reference speed through the setting input unit 80) (step S12). If the reference speed is calculated, in the movement speed calculation unit 75, the movement speed (dwell time T) of the dresser in each scanning area is set by taking the target cutting amount U0 of the dresser and the pad wear amount U in each monitoring area as the minimum value of the following evaluation index J (step S13). Alternatively, the calculated reference speed can be set as the initial value of the movement speed. J = |U - U0|2

[0076] Then, when setting the substrate W, the substrate W is ground and cleaned (step S14), and the basic contour is calculated when specified conditions are met. In addition, when other conditions are met, the cutting rate is calculated or the dressing speed is updated (see Figure 13). The pad replacement indicator can also be determined by the number of substrate W to be processed, or it can be automatically determined based on the height of the grinding pad.

[0077] Figure 13 is a flowchart of the processing procedure for the display substrate W. When the device control unit 15 outputs a substrate start processing command (step S30), the trimmer control unit 60 determines whether the specified conditions are met (the example in Figure 13 is whether the cutting rate calculation cycle has been reached (for example, grinding a specified number of substrates W)) (step S31). When reached, the reference load pad height described later is calculated (step S32). Furthermore, in the cutting rate calculation unit 73, the cutting rate of the trimmer in each scanning area is calculated and updated (step S33). In addition, if the conditions are not met, the cutting rate update process is skipped.

[0078] Further, the trimmer control unit 60 determines whether a specified condition is met (in the example of Figure 13, whether the moving speed update cycle has been reached (e.g., grinding a specified number of substrates W)) (step S34). When reached, the reference load pad height is calculated (step S35), and in the moving speed calculation unit 75, the trimmer moving speed in each scanning area is optimized by calculating the dwell time of the trimmer that minimizes the evaluation index J (step S36). Then, the optimized moving speed value is set, and the trimmer moving speed (trimming scheme) is updated (step S37).

[0079] Figure 14 is a flowchart showing the calculation process of the reference load pad height in step S35 (and step S32). The pad height correction unit 78 reads the measured value data of the pad height stored in the correction data storage unit 79 (step S50). Next, the pad height correction unit 78 takes the average value of the measured values ​​at the corresponding radius position for each monitoring area of ​​the grinding pad and calculates the average pad height of each monitoring area (step S51), which is used as the measured value of the pad height PadHmeasure(r) (step S51). Alternatively, instead of calculating the average value of each monitoring area, the measured value at each radius position is used as PadHmeasure(r).

[0080] Next, the pad height correction unit 78 reads two adjuster loads (DF1, DF2) that are close to the adjuster load (measured load) DFx set by the adjuster load setting unit 77, and the pad height reference data (PadH1, PadH2) corresponding to the adjuster loads (step S52). Similarly, it reads two adjuster loads that are close to the reference load, and the corresponding pad height reference data.

[0081] The pad height correction unit 78 calculates the radius position of each grinding pad from the read dressing weight and pad height reference data by interpolating the reference weight and the pad height corresponding to the measured weight (step S53). Then, it generates a calculation formula F(DF, r) for the correction amount of the pad height to the measured weight from the pad height information obtained by interpolation (step S54).

[0082] Next, the pad height correction unit 78 calculates the correction amount PadHdelta(r) of the radius position corresponding to the measured value PadHmeasure(r) of the pad height from the obtained calculation formula F(DF, r) (step S55), and calculates the reference load pad height PadH(r) from the correction amount (step S56).

[0083] In Figure 13, the reference load pad height PadH(r) is calculated. When the calculation is completed according to the calculation conditions, the substrate W set on the substrate polishing unit is polished (step S38). The polishing of the substrate W can be carried out until the preset film thickness is reached or the substrate layer is exposed. When the polished substrate W is taken out from the substrate polishing unit, the trimmer control unit 60 drives the trimmer 51 to perform the trimming process of the polishing pad 43 according to the set trimming scheme (step S39). When the polishing pad 43 is trimmed, the height of the polishing surface 43a (pad height) is measured by the pad height sensor 58 (step S40), and the measured data is stored in the memory of the trimmer control unit 60 (step S41). The polished substrate W is sent to the cleaning unit 14 (first substrate cleaning device 30, second substrate cleaning device 31, substrate drying device 32) for substrate cleaning and drying (step S42), and then taken out from the substrate processing device 10.

[0084] In Figure 12, when the substrate processing is completed, it is determined whether the conditions for obtaining the basic contour are met (for example, grinding a specified number of substrates W) (step S15). If the conditions are met, the target contour (basic contour) of the pad height at convergence is calculated in the basic contour calculation unit 72 (step S16). If the conditions for obtaining the basic contour are not met (when the specified number of substrates W are not ground), the process returns to step S14, and the next substrate W is ground and cleaned.

[0085] When setting the basic outline, the next substrate W is ground and cleaned (step S17). Since this grinding and cleaning process is the same as that described in the flowchart of FIG13, detailed explanation is omitted. Then, before the cutting amount of the grinding pad increases and falls below the replacement reference value (step S18), the substrate processing continues in step S17. Then, when the height of the grinding pad falls below the replacement reference value (step S18 is "Yes (Y)"), the device control unit 15 instructs the operator to replace the grinding pad via the output unit 66 (step S19).

[0086] Figure 15 is an example graph showing the relationship between pad height and the radius position of the grinding pad when the dresser load is changed from 12N to 24N. Without pad height correction (Figure 15(a)), when the dresser load increases to 24N, the measured value of the pad height profile (compared to 12N) decreases, making it impossible to accurately calculate the dresser's movement speed. In contrast, with pad height correction (Figure 15(b)), even with an increase in dresser load, the measured value of the pad height profile (compared to 12N) remains almost unchanged, allowing for a more accurate calculation of the dresser's movement speed.

[0087] Because the thickness of the polishing pad 43 varies depending on the pad's thickness, elastic coefficient (pad hardness), and cross-sectional area, the reference weighting correction data should be pre-set for each polishing pad. In addition, since the polishing pad 43 only wears slightly each time it is dressed, when the number of dressings increases, a significant change in wear will occur when comparing the thickness of the polishing pad after replacement.

[0088] Therefore, when calculating the reference load pad height PadH(r) (step S56), an adjustment coefficient f(t) based on the pad's usage time (or the amount of wear) can also be added to calculate the pad height. In this case, the reference load pad height PadH(r) can be calculated using the following formula: PadH(r) = PadHmeasure(r) + f(t) × PadHdelta(r)

[0089] Here, the adjustment coefficient f(t) can be set by prior testing. Here, it can also be set as a function of the use time t of the polishing pad, with the number of times the dressing device processes the polishing pad as the argument.

[0090] The above embodiments are described with the aim of enabling those skilled in the art to implement the present invention. Those skilled in the art can naturally create various modifications to the above 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, but should be interpreted according to the broadest scope of the technical concept defined by the claims. [Simplified Explanation of the Diagram]

[0011] Figure 1 is a schematic top view showing the configuration of a substrate processing apparatus according to one embodiment of the present invention. Figure 2 is a schematic diagram showing a polishing apparatus for polishing a substrate. Figure 3 is a schematic top view showing a trimmer and a polishing pad. Figure 4 is an example diagram showing a scanning area set on the polishing pad. Figure 5 is an explanatory diagram showing the relationship between the scanning area and the monitoring area of ​​the polishing pad. Figure 6 is an example block diagram showing the functional block configuration of the trimmer control unit. Figure 7 is an example explanatory diagram showing the contour change of the polishing pad height in each scanning area. Figure 8 is an example explanatory diagram showing the trimmer movement speed and reference value in each scanning area. Figure 9 is an example graph showing the relationship between the pad height and the polishing pad radius position when the trimmer load changes. Figure 10 is an example graph showing the relationship between the pad height and the polishing pad radius position when the set value (measured load) of the trimmer load changes from the reference load. Figure 11 is an example graph showing the correction amount of the pad height to the polishing pad radius position. Figure 12 is a flowchart illustrating an example of the operation of a substrate processing apparatus on a polishing pad. Figure 13 is a flowchart illustrating an example of a substrate processing procedure. Figure 14 is a flowchart illustrating an example of the calculation process for the reference load pad height. Figure 15 is a graph illustrating an example of the relationship between the pad height and the radius position of the polishing pad when the load of the trimmer is changed, (a) showing the case without pad height correction, and (b) showing the case with pad height correction.

Claims

1. A substrate processing apparatus for polishing a substrate by sliding contact with a polishing member, comprising: a trimmer that trims the polishing member by oscillating on the polishing member, and whose oscillation speed is adjustable in a plurality of scanning areas set on the polishing member along the radial direction; a height sensor that measures the height of the trimmer; a pad height detection unit that generates a pad profile by measuring the surface height of the polishing member in contact with the trimmer along the radial direction of the polishing member based on the height of the trimmer measured by the height sensor; a trimmer load setting unit that sets a trimmer load imposed on the polishing member by the trimmer; and a pad height correction unit that calculates a correction amount for the change in the surface height of the polishing member relative to a reference load based on the trimmer load at a plurality of points along the radial direction, and corrects the pad profile by correcting the measured surface height values ​​at a plurality of points along the radial direction of the polishing member with the correction amount. The moving speed calculation unit adjusts the oscillation speed of the dresser in each scanning area based on the corrected pad profile described above; and the correction data memory unit stores multiple pad height reference data along the radial direction described above for each reference dresser load. The aforementioned correction amount is not the same in the radial direction of the aforementioned grinding member, and the aforementioned pad height correction part is calculated by interpolating the aforementioned surface height correction amount from the aforementioned pad height reference data corresponding to the aforementioned reference dresser load that is close to the set aforementioned dresser load and the aforementioned pad height reference data corresponding to the aforementioned reference dresser load that is close to the aforementioned reference load.

2. The substrate processing apparatus of claim 1, wherein the aforementioned pad height reference data is set for each of the aforementioned grinding members and / or the aforementioned trimmers.

3. The substrate processing apparatus of claim 1, wherein the aforementioned pad height correction unit corrects the aforementioned surface height by means of a correction coefficient based on the usage time of the aforementioned grinding member or the number of times the aforementioned dressing device has been dressed.

4. The substrate processing apparatus of claim 1, wherein the aforementioned height detection unit measures the surface height of the aforementioned polishing member in a plurality of monitoring areas pre-set along the radial direction of the aforementioned polishing member.

5. The substrate processing apparatus of claim 1, comprising: a trimming model row generation unit that generates trimming model rows defined by a plurality of monitoring areas, scanning areas and trimming models; and an evaluation index generation unit that calculates a height profile prediction value using the trimming model and the oscillation speed or dwell time in each scanning area, and sets an evaluation index based on the difference between the height profile of the polishing member and the target value; and a movement speed calculation unit that calculates the oscillation speed of the trimmer in each scanning area based on the evaluation index.

6. A method for trimming a polishing member, comprising trimming the polishing member by oscillating a trimmer on a polishing member of a polishing apparatus used on a substrate, wherein the trimmer can adjust the oscillation speed of the trimmer at a plurality of scanning areas set on the polishing member along the oscillation direction, and the trimming method comprising: a trimmer height measurement step, wherein the height of the trimmer is measured by a height sensor; a pad height measurement step, wherein a pad profile is generated by measuring the surface height of the polishing member in contact with the trimmer along the radial direction of the polishing member based on the height of the trimmer measured by the height sensor; a trimmer load setting step, wherein a trimmer load is set by the trimmer to be applied to the polishing member; and a pad height correction step, wherein a correction amount is calculated for the change in the surface height of the polishing member relative to the trimmer load relative to a reference load at a plurality of points along the radial direction, and the pad profile is corrected by correcting the measured surface height values ​​at a plurality of points along the radial direction of the polishing member with the correction amount. The moving speed calculation step involves adjusting the oscillation speed of the dresser in each scanning area based on the corrected previously described pad profile; and the data correction and memory step involves corresponding to the load of a plurality of reference dressers to memorize a plurality of pad height reference data along the previously described radial direction of the aforementioned grinding member; wherein... The aforementioned correction amount is not the same in the radial direction of the aforementioned grinding member, and the aforementioned pad height correction step is calculated by interpolating the aforementioned surface height correction amount from the aforementioned pad height reference data corresponding to the aforementioned reference dresser load close to the set aforementioned dresser load and the aforementioned pad height reference data corresponding to the aforementioned reference dresser load close to the aforementioned reference load.

7. A non-transitory computer-readable recording medium, for a computer of a polishing apparatus that uses a trimmer to trim a polishing member for polishing a substrate by oscillating the trimmer, wherein the trimmer's oscillation speed can be adjusted in a plurality of scanning areas set on the polishing member along the oscillation direction, includes execution code for performing the following steps: a trimmer height measurement step, wherein the height of the trimmer is measured by a height sensor; a pad height measurement step, wherein a pad profile is generated by measuring the surface height of the polishing member in contact with the trimmer along the radial direction of the polishing member based on the height of the trimmer measured by the height sensor; and a trimmer load setting step, wherein the trimmer load imposed on the polishing member by the trimmer is set. The pad height correction step involves calculating a correction amount for the surface height of the grinding component, based on the variation of the dresser load with the reference load, at multiple points along the aforementioned radial direction. The pad profile is corrected by adjusting the measured surface height values ​​at multiple points along the radial direction of the grinding component using this correction amount. The movement speed calculation step adjusts the oscillation speed of the dresser in each scanning area based on the corrected pad profile. The correction data memory step stores multiple pad height reference data along the aforementioned radial direction of the grinding component, corresponding to multiple reference dresser loads. The aforementioned correction amount is not the same in the radial direction of the aforementioned grinding member, and the aforementioned pad height correction step is calculated by interpolating the aforementioned surface height correction amount from the aforementioned pad height reference data corresponding to the aforementioned reference dresser load close to the set aforementioned dresser load and the aforementioned pad height reference data corresponding to the aforementioned reference dresser load close to the aforementioned reference load.

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