Substrate polishing apparatus, substrate processing apparatus, method, program and storage medium

Abstract

To achieve good profile control of the polishing material. [Solution] The substrate polishing apparatus is a dresser that dresses a polishing member by oscillating on the polishing member, and comprises a dresser capable of adjusting the load and rotation speed in a plurality of scan areas set on the polishing member along the direction of oscillation, a height detection unit that measures the surface height of the polishing member in a plurality of monitor areas set in advance on the polishing member along the direction of oscillation of the dresser, a dress model matrix creation unit that creates a dress model matrix defined from the plurality of monitor areas, scan areas and dress model, an evaluation index creation unit that calculates a height profile prediction value using the dress model and the oscillation speed or stay time of the dresser in each scan area and creates an evaluation index based on the difference from the target value of the height profile of the polishing member, and a calculation unit that calculates the load and rotation speed of the dresser in each scan area of ​​the dresser based on the evaluation index.

Description

[Technical Field]

[0001] The present invention relates to a substrate polishing apparatus, a substrate processing apparatus, a method, a program, and a storage medium. [Background technology]

[0002] As semiconductor devices become more highly integrated, circuit wiring becomes smaller, and the dimensions of the integrated devices are also becoming smaller. Therefore, a process is needed to polish wafers, which have a film of, for example, metal, formed on their surface, to flatten the wafer surface. One method of this flattening is polishing using a chemical mechanical polishing (CMP) apparatus. A chemical mechanical polishing apparatus has polishing members (polishing cloth, polishing pad, etc.) and a holding part (top ring, polishing head, chuck, etc.) that holds the object to be polished, such as a wafer. The surface of the object to be polished (the surface to be polished) is pressed against the surface of the polishing members, and while supplying a polishing liquid (abrasive fluid, chemical solution, slurry, pure water, etc.) between the polishing members and the object to be polished, the polishing members and the object to be polished are moved relative to each other to polish the surface of the object to be polished flat.

[0003] The materials used for abrasive components in such chemical mechanical polishing equipment are generally foamed resins or nonwoven fabrics. The surface of the abrasive component has fine irregularities, which act as chip pockets that are effective in preventing clogging and reducing polishing resistance. However, if the polishing of the workpiece is continued with the abrasive component, the fine irregularities on the surface of the abrasive component become flattened, causing a decrease in the polishing rate of the workpiece. Therefore, the surface of the abrasive component is dressed (sharpened) with a dresser to which a large number of abrasive grains such as diamond particles are electroplated, and the fine irregularities on the surface of the abrasive component are reformed.

[0004] One method for dressing abrasive materials involves moving a rotating dresser (in an arc-shaped or linear reciprocating motion, or oscillating motion) while pressing the dressing surface against the rotating abrasive material. During the dressing process, a small amount of material is removed from the surface of the abrasive material. Therefore, if dressing is not performed properly, an inappropriate undulation will occur on the surface of the abrasive material, causing variations in the polishing rate of the object being polished. Since variations in the polishing rate can lead to polishing defects, it is necessary to control the profile of the abrasive material by performing proper dressing to prevent the formation of inappropriate undulations on the surface of the abrasive material. In other words, it is necessary to avoid variations in the cutting rate of the abrasive material and prevent the formation of inappropriate undulations by performing dressing at an appropriate movement speed of the dresser.

[0005] However, when the dressing time is short, the movement speed of the dresser cannot be changed, which presents a problem in that it is not possible to properly control the profile of the polishing material under such constraints. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-99966 [Overview of the project] [Problems that the invention aims to solve]

[0007] The objective of this invention is to effectively control the profile of the polishing member. [Means for solving the problem]

[0008] [1] A substrate polishing apparatus according to one aspect of the present invention is A substrate polishing apparatus that polishes a substrate by sliding it against an abrasive member, A dresser that dresses the polishing member by swinging on the polishing member, the dresser being capable of adjusting the load and rotational speed in a plurality of scan areas set on the polishing member along the swinging direction. A height detection unit that measures the surface height of the polishing member in a plurality of monitor areas preset on the polishing member along the swinging direction of the dresser. A dress model matrix creation unit that creates a dress model matrix defined from a plurality of monitor areas, scan areas, and dress models. An evaluation index creation unit that calculates a predicted value of the height profile using the dress model and the swinging speed or residence time of the dresser in each scan area, and creates an evaluation index based on the difference from the target value of the height profile of the polishing member. A calculation unit that calculates the load and rotational speed of the dresser in each scan area of the dresser based on the evaluation index. It is provided with.

[0009] [2] The substrate polishing apparatus according to one aspect of the present invention is as described in [1] above, The polishing member is dressed by simultaneously changing the load and rotational speed of the dresser calculated by the calculation unit.

[0010] [3] The substrate polishing apparatus according to one aspect of the present invention is as described in [1] or [2] above, The polishing member is dressed in a state where the swinging speed of the dresser is constant.

[0011] [4] The substrate polishing apparatus according to one aspect of the present invention is as described in any one of [1] to [3] above, The evaluation index includes a first parameter corresponding to the load of the dresser and a second parameter corresponding to the rotational speed of the dresser, The evaluation index creation unit creates the evaluation index so that the weight of the second parameter is greater than the weight of the first parameter.

[0012] [5] A substrate processing apparatus according to one aspect of the present invention comprises a substrate polishing apparatus as described in any of [1] to [4] above.

[0013] [6] A method according to one aspect of the present invention is A method for adjusting the load and rotation speed in a plurality of scan areas set on a polishing member, along the direction of oscillation of a dresser that dresses a polishing member by oscillating on the polishing member for polishing a substrate, The surface height of the polishing member is measured in a plurality of pre-set monitoring areas on the polishing member along the oscillation direction of the dresser, Creating a dress model matrix defined from multiple monitor areas, scan areas, and dress models, The method involves calculating a predicted height profile using the dressing model and the oscillation speed or residence time of the dresser in each scan area, and creating an evaluation index based on the difference from the target value of the height profile of the polishing member. Based on the evaluation index, the load and rotational speed of the dresser in each scan area of ​​the dresser are calculated, Includes.

[0014] [7] A program according to one aspect of the present invention is a program that causes a computer to execute the method described in [6] above.

[0015] [8] A storage medium according to one aspect of the present invention is a storage medium that is readable by a computer storing the program described in [7] above. [Effects of the Invention]

[0016] According to the present invention, the profile of the polishing member can be controlled effectively. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic diagram showing a polishing apparatus used to polish substrates such as wafers. [Figure 2]This is a schematic plan view showing the dresser and polishing pad. [Figure 3] This figure shows an example of a scan area set on a polishing pad. [Figure 4] This is an explanatory diagram showing the relationship between the scanning area and the monitoring area of ​​the polishing pad. [Figure 5] This is a block diagram showing an example of the configuration of a dresser monitoring device. [Figure 6] This is an explanatory diagram showing an example of the profile change in polishing pad height in each scan area. [Figure 7] This flowchart shows an example of the procedure for adjusting the parameters of a dresser. [Figure 8] This figure shows a comparison of the current profile and the target profile. [Modes for carrying out the invention]

[0018] An embodiment of the present invention will be described with reference to the drawings. Figure 1 is a schematic diagram showing a polishing apparatus for polishing substrates such as wafers. The polishing apparatus is provided in a substrate processing apparatus that can perform a series of processes including polishing, cleaning, and drying the wafer.

[0019] As shown in Figure 1, the polishing apparatus comprises a polishing unit 10 for polishing a wafer W, a polishing table 12 for holding a polishing pad (polishing member) 11, a polishing liquid supply nozzle 13 for supplying polishing liquid onto the polishing pad 11, and a dressing unit 14 for conditioning (dressing) the polishing pad 11 used for polishing the wafer W. The polishing unit 10 and the dressing unit 14 are mounted on a base 15.

[0020] The polishing unit 10 includes a top ring (substrate holding part) 20 connected to the lower end of the top ring shaft 21. The top ring 20 is configured to hold the wafer W on its lower surface by vacuum suction. The top ring shaft 21 rotates by the drive of a motor (not shown), and the rotation of the top ring shaft 21 causes the top ring 20 and the wafer W to rotate. The top ring shaft 21 moves up and down relative to the polishing pad 11 by a vertical movement mechanism (not shown) (for example, a vertical movement mechanism consisting of a servo motor and a ball screw).

[0021] The polishing table 12 is connected to a motor (not shown) located below it. The polishing table 12 is rotated around its axis by the motor. A polishing pad 11 is attached to the upper surface of the polishing table 12, and the upper surface of the polishing pad 11 constitutes the polishing surface 11a for polishing the wafer W.

[0022] The wafer W is polished as follows: The top ring 20 and the polishing table 12 are rotated, and polishing fluid is supplied onto the polishing pad 11. In this state, the top ring 20 holding the wafer W is lowered, and a pressurizing mechanism (not shown) consisting of an airbag installed inside the top ring 20 presses the wafer W against the polishing surface 11a of the polishing pad 11. The wafer W and the polishing pad 11 are brought into sliding contact with each other in the presence of the polishing fluid, thereby polishing and flattening the surface of the wafer W.

[0023] The dressing unit 14 includes a dresser 23 that contacts the polishing surface 11a of the polishing pad 11, a dresser shaft 24 connected to the dresser 23, an air cylinder 25 provided at the upper end of the dresser shaft 24, and a dresser arm 26 that rotatably supports the dresser shaft 24. Abrasive particles such as diamond particles are fixed to the lower surface of the dresser 23. The lower surface of the dresser 23 constitutes the dressing surface for dressing the polishing pad 11.

[0024] 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 that applies a dressing load to the polishing pad 11 to the dresser 23. The dressing load can be adjusted by the air pressure supplied to the air cylinder 25.

[0025] The dresser arm 26 is driven by a motor 30 and is configured to swing about a pivot shaft 31. The dresser shaft 24 is rotated by a motor (not shown) installed inside the dresser arm 26, and the rotation of this dresser shaft 24 causes the dresser 23 to rotate about its axis. The air cylinder 25 presses the dresser 23 against the polishing surface 11a of the polishing pad 11 with a predetermined load via the dresser shaft 24.

[0026] Conditioning of the polishing surface 11a of the polishing pad 11 is performed as follows: The polishing table 12 and the polishing pad 11 are rotated by a motor, and a dressing liquid (e.g., pure water) is supplied to the polishing surface 11a of the polishing pad 11 from a dressing liquid supply nozzle (not shown). Furthermore, the dresser 23 is rotated around its axis. The dresser 23 is pressed against the polishing surface 11a by an air cylinder 25, and the lower surface (dressing surface) of the dresser 23 is brought into sliding contact with the polishing surface 11a. In this state, the dresser arm 26 is rotated, causing the dresser 23 on the polishing pad 11 to swing in approximately the radial direction of the polishing pad 11. The polishing pad 11 is scraped by the rotating dresser 23, thereby conditioning the polishing surface 11a.

[0027] A pad height sensor (surface height measuring device) 32 is fixed to the dresser arm 26 to measure the height of the polishing surface 11a. A sensor target 33 is fixed to the dresser shaft 24, facing the pad height sensor 32. The sensor target 33 moves up and down together with the dresser shaft 24 and the dresser 23, while the vertical position of the pad height sensor 32 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 polishing surface 11a (thickness of the polishing pad 11) can be measured indirectly. Since the sensor target 33 is connected to the dresser 23, the pad height sensor 32 can measure the height of the polishing surface 11a while the polishing pad 11 is being conditioned.

[0028] The height of the polishing surface 11a is measured by the pad height sensor 32 in multiple predetermined areas (monitor areas) divided in the radial direction of the polishing pad. The pad height sensor 32 indirectly measures the polishing surface 11a from the vertical position of the dresser 23 that is in contact with the polishing surface 11a. Therefore, the average height of the polishing surface 11a in the area (a certain monitor area) in contact with the lower surface (dressing surface) of the dresser 23 is measured by the pad height sensor 32, and by measuring the height of the polishing pad in multiple monitor areas, the profile of the polishing pad (cross-sectional shape of the polishing surface 11a) can be obtained. Any type of sensor can be used as the pad height sensor 32, such as a linear scale sensor, a laser sensor, an ultrasonic sensor, or an eddy current sensor.

[0029] The pad height sensor 32 is connected to the dressing monitoring device 35, and the output signal of the pad height sensor 32 (i.e., the measured height of the polishing surface 11a) is sent to the dressing monitoring device 35. The dressing monitoring device 35 has the function of obtaining a profile of the polishing pad 11 from the measured height of the polishing surface 11a and further determining whether the polishing pad 11 has been conditioned correctly.

[0030] The polishing apparatus includes a table rotary encoder 36 for measuring the rotation angles of the polishing table 12 and polishing pad 11, and a dresser rotary encoder 37 for measuring the rotation angle of the dresser 23. These table rotary encoders 36 and dresser rotary encoders 37 are absolute encoders that measure the absolute value of the angle. These rotary encoders 36 and 37 are connected to a dressing monitoring device 35, which can acquire the rotation angles of the polishing table 12 and polishing pad 11, as well as the rotation angle of the dresser 23, when the height of the polishing surface 11a is measured by the pad height sensor 32.

[0031] The dresser 23 is connected to the dresser shaft 24 via a universal joint 17. The dresser shaft 24 is connected to a motor (not shown). The dresser shaft 24 is rotatably supported by a dresser arm 26, and this dresser arm 26 allows the dresser 23 to swing radially around the polishing pad 11 while in contact with the polishing pad 11, as shown in Figure 2. The universal joint 17 is configured to transmit the rotation of the dresser shaft 24 to the dresser 23 while allowing the dresser 23 to tilt. The dressing unit 14 is composed of the dresser 23, universal joint 17, dresser shaft 24, dresser arm 26, and a rotating mechanism (not shown). A dressing monitoring device 35 that calculates the sliding distance and sliding speed of the dresser 23 is electrically connected to this dressing unit 14. A dedicated or general-purpose computer can be used as this dressing monitoring device 35.

[0032] Abrasive particles, such as diamond particles, are fixed to the lower surface of the dresser 23. The portion where these abrasive particles are fixed constitutes the dressing surface that dresses the polishing surface of the polishing pad 11. The dressing surface can be configured as a circular dressing surface (a dressing surface in which abrasive particles are fixed to the entire lower surface of the dresser 23), a ring-shaped dressing surface (a dressing surface in which abrasive particles are fixed to the peripheral edge of the lower surface of the dresser 23), or multiple circular dressing surfaces (a dressing surface in which abrasive particles are fixed to the surface of multiple small-diameter pellets arranged at approximately equal intervals around the center of the dresser 23). In this embodiment, the dresser 23 is provided with a circular dressing surface.

[0033] When dressing the polishing pad 11, as shown in Figure 1, the polishing pad 11 is rotated at a predetermined rotational speed in the direction of the arrow, and the dresser 23 is rotated at a predetermined rotational speed in the direction of the arrow by a rotation mechanism (not shown). In this state, the dressing surface of the dresser 23 (the surface on which the abrasive grains are arranged) is pressed against the polishing pad 11 with a predetermined dressing load to dress the polishing pad 11. In addition, the dresser 23 is oscillated on the polishing pad 11 by the dresser arm 26, thereby dressing the area of ​​the polishing pad 11 used for polishing (the polishing area, i.e., the area on which the object to be polished, such as a wafer, is polished).

[0034] Since the dresser 23 is connected to the dresser shaft 24 via a universal joint 17, the dressing surface of the dresser 23 will properly contact the polishing pad 11 even if the dresser shaft 24 is slightly tilted relative to the surface of the polishing pad 11. Above the polishing pad 11, a pad roughness measuring instrument 38 is positioned to measure the surface roughness of the polishing pad 11. As this pad roughness measuring instrument 38, a known non-contact type surface roughness measuring instrument such as an optical type can be used. The pad roughness measuring instrument 38 is connected to a dressing monitoring device 35, and the measured values ​​of the surface roughness of the polishing pad 11 are sent to the dressing monitoring device 35.

[0035] A film thickness sensor (film thickness measuring device) 39 for measuring the film thickness of the wafer W is positioned inside the polishing table 12. The film thickness sensor 39 is positioned facing the surface of the wafer W held by the top ring 20. The film thickness sensor 39 is a film thickness measuring device that measures the film thickness of the wafer W while moving across the surface of the wafer W as the polishing table 12 rotates. Non-contact type sensors such as eddy current sensors and optical sensors can be used as the film thickness sensor 39. The measured film thickness is sent to the dressing monitoring device 35. The dressing monitoring device 35 is configured to generate a film thickness profile of the wafer W (film thickness distribution along the radial direction of the wafer W) from the measured film thickness.

[0036] Next, the oscillation of the dresser 23 will be explained with reference to Figure 2. The dresser arm 26 rotates clockwise and counterclockwise by a predetermined angle around point J. The position of point J corresponds to the center position of the support shaft 31 shown in Figure 1. As a result of the rotation of the dresser arm 26, the rotation center of the dresser 23 oscillates radially in the range indicated by the arc L of the polishing pad 11.

[0037] Figure 3 is an enlarged view of the polishing surface 11a of the polishing pad 11. As shown in Figure 3, the oscillation range (oscillation width L) of the dresser 23 is divided into several (seven in the example of Figure 3) scan areas (oscillation sections) S1 to S7. These scan areas S1 to S7 are pre-set virtual sections on the polishing surface 11a and are aligned along the oscillation direction of the dresser 23 (i.e., roughly in the radial direction of the polishing pad 11). The dresser 23 dresses the polishing pad 11 while moving across these scan areas S1 to S7. The lengths of these scan areas S1 to S7 may be the same or different.

[0038] Figure 4 is an explanatory diagram showing the positional relationship between the scan areas S1 to S7 and the monitor areas M1 to M10 of the polishing pad 11, with the horizontal axis of the figure representing the distance from the center of the polishing pad 11. In this embodiment, the case where seven scan areas and ten monitor areas are set is used as an example, but these numbers can be changed as appropriate. In addition, since it is difficult to control the pad profile in the area corresponding to the radius of the dresser 23 from both ends of the scan area, monitor exclusion widths are provided on the inside (areas R1 to R3 in Figure 4) and outside (areas R4 to R2 in Figure 4), but it is not always necessary to provide exclusion widths. In other words, the scan area and the monitor area may be the same.

[0039] The movement speed of the dresser 23 while it is oscillating on the polishing pad 11 is predetermined for each scan area S1 to S7, and can be adjusted as needed if there are no constraints on the dressing time.

[0040] The movement speed of the dresser 23 is one of the determining factors for the pad height profile of the polishing pad 11. The cut rate of the polishing pad 11 represents the amount (thickness) of the polishing pad 11 that is removed by the dresser 23 per unit time. When the dresser is moved at a constant speed, the thickness of the polishing pad 11 removed in each scan area is usually different, so the cut rate value will also differ for each scan area. However, since it is usually preferable to maintain the initial shape of the pad profile, the movement speed is adjusted so that the difference in the amount of material removed in each scan area is small.

[0041] Increasing the movement speed of the dresser 23 means shortening the time the dresser 23 stays on the polishing pad 11, that is, reducing the amount of material removed from the polishing pad 11. On the other hand, decreasing the movement speed of the dresser 23 means lengthening the time the dresser 23 stays on the polishing pad 11, that is, increasing the amount of material removed from the polishing pad 11. Therefore, by increasing the movement speed of the dresser 23 in a certain scan area, the amount of material removed in that scan area can be reduced, and by decreasing the movement speed of the dresser 23 in a certain scan area, the amount of material removed in that scan area can be increased. This allows for adjustment of the overall pad height profile of the polishing pad.

[0042] However, when there are constraints on the dressing time, it is difficult to change the movement speed of the dresser. Therefore, in this embodiment, instead of adjusting the movement speed of the dresser, the profile of the polishing pad 11 is controlled by adjusting the load and rotation speed of the dresser.

[0043] Figure 8 shows the relationship between the pad radius position (radial position of the polishing member) and the pad height. As shown in Figure 8, there is a difference between the current profile of the polishing pad and the target profile. In this embodiment, the load and rotation speed of the dresser are adjusted to minimize this difference.

[0044] Next, the functional configuration of the dressing monitoring device 35 according to this embodiment will be described.

[0045] As shown in Figure 5, the dressing monitoring device 35 includes a dressing model setting unit 41, a base profile calculation unit 42, a cut rate calculation unit 43, an evaluation index creation unit 44, a parameter value calculation unit 45, a setting input unit 46, a memory 47, and a pad height detection unit 48. It acquires a profile of the polishing pad 11 and, at a predetermined timing, sets the movement speed of the dresser 23 in the scan area to be optimal.

[0046] The dress model setting unit 41 sets a dress model S for calculating the amount of wear of the polishing pad 11 in the scan area. The dress model S is an m x n real matrix where the number of divisions of the monitor area is m (10 in this embodiment) and the number of divisions of the scan area is n (7 in this embodiment), and is determined by various parameters described later. If the scan area and the monitor area are the same, the dress model S is S = [s1, s2, ..., s n ]

[0047] The scan speed of the dresser in each scan area set by the polishing pad 11 is V = [v1, v2, ..., v n ], the width of each scan area is W=[w1, w2, ..., w n When this is the case, the time spent at the dresser (center) in each scan area is: T=W / V=[w1 / v1, w2 / v2, …, w n / v n ] It is expressed as follows: In this case, the amount of pad wear in each monitor area is U = [u1, u2, ..., u m When this is the case, using the aforementioned dress model S and the time spent in each scan area T, U=ST The pad wear amount U is calculated by performing a matrix operation.

[0048] In deriving the dress model matrix S, for example, the following elements can be considered and combined as appropriate: 1) cut rate model, 2) dresser diameter, and 3) scan speed control. Regarding the cut rate model, it is assumed that each element of the dress model matrix S is proportional to the time spent in the monitor area, or proportional to the scratching distance (travel distance).

[0049] Also, regarding the dresser diameter, each element of the dressing model matrix S is set on the premise of considering the diameter of the dresser (the polishing pad wears according to the same cutting rate over the entire effective area of the dresser) or not considering it (adopting the cutting rate only at the center position of the dresser). Considering the dresser diameter enables defining an appropriate dressing model even for a dresser with diamond particles coated in a ring shape, for example. Further, regarding the scan speed control, each element of the dressing model matrix S is set according to whether the change in the moving speed of the dresser is step-shaped or slope-shaped. By appropriately combining these parameters, a cutting amount closer to the actual situation can be calculated from the dressing model S to obtain a correct profile prediction value.

[0050] The pad height detection unit 48 associates the height data of the polishing pad continuously measured by the pad height sensor 32 with the measurement coordinate data on the polishing pad to detect the pad height in each monitor area.

[0051] The base profile calculation unit 42 calculates the target profile (base profile) of the pad height at the time of convergence (see FIG. 6). The base profile is used for calculating the target cutting amount to be used by the parameter value calculation unit 45 described later. The base profile may be calculated based on the height distribution (Diff(j)) of the polishing pad in the initial state of the pad and the measured pad height, or may be given as a set value. Also, when not setting the base profile, the target cutting amount for making the shape of the polishing pad flat may be calculated.

[0052] The basis of the target cutting amount is the pad height profile H p (j) [j = 1, 2…m] of the pad height for each monitor area at the current time and the separately set target depletion amount A tg and is calculated by the following formula.

[0053] min{H p (j)} - A tg Furthermore, the target cut amount for each monitoring area can be calculated using the following formula, taking into account the base profile mentioned above.

[0054] min{H p (j) -A tg +Diff(j) The cut rate calculation unit 43 calculates the cut rate of the dresser in each monitor area. For example, the cut rate may be calculated from the slope of the change in pad height in each monitor area (the amount of change in pad height per unit time).

[0055] The evaluation index creation unit 44 optimizes the parameter values ​​of the dresser in each scan area using the evaluation index described later.

[0056] This evaluation index includes at least parameter values ​​corresponding to 1) deviation from the target cut amount, 2) deviation from the load in the standard recipe, and 3) deviation from the rotation speed in the standard recipe. The dresser load and rotation speed are optimized by determining the parameter values ​​in each scan area so that this evaluation index is minimized.

[0057] 1) Deviation from the target cut amount The target cut amount for the dresser is U0 = [U 01 , U 02 , ..., U 0m When this is the case, the square of the difference between the pad wear amount U (=ST) in each monitor area mentioned above (|U-U0|) 2 The deviation from the target cutting amount is calculated by determining the ) value. The target profile for determining the target cutting amount can be determined at any time after the start of use of the polishing pad, or it may be determined based on a manually set value.

[0058] 2) Deviation from the load in the standard recipe The square of the difference (ΔDRP) between the dresser load (reference load (reference pressure DRP0)) based on the reference recipe set in each scan area and the dresser load DRP in each scan area (ΔDRP)2 =|DRP-DRP0| 2 By determining the (first parameter), the deviation from the load in the reference recipe can be calculated. Here, the reference load is the load at which a flat cut rate is expected to be obtained in each scan area, and is a value obtained in advance through experiments or simulations. When determining the reference load by simulation, for example, it can be determined by assuming that the load of the dresser and the amount of cutting by the polishing pad are proportional. Note that the reference load may be updated as needed in accordance with the actual cut rate while using the same polishing pad.

[0059] 3) Deviation from the rotation speed in the standard recipe The square of the difference (ΔDRR) between the dresser rotation speed (reference rotation speed DRR0) based on the reference recipe set in each scan area and the dresser rotation speed DRR in each scan area (ΔDRR) 2 =|DRR-DRR0| 2 By determining the (second parameter), the deviation from the rotation speed in the reference recipe can be calculated. Here, the reference rotation speed is the rotation speed at which a flat cut rate is expected to be obtained in each scan area, and is a value obtained in advance through experiments or simulations. When determining the reference rotation speed by simulation, for example, it can be determined by assuming that the rotation speed of the dresser and the cutting amount of the polishing pad are proportional. Note that the reference rotation speed may be updated as needed in accordance with the actual cut rate while using the same polishing pad.

[0060] The evaluation indicator creation unit 44 defines the evaluation indicator J shown in the following formula based on these three indicators.

[0061] J=|U-U0| 2 +λ 2 |DRP-DRP0| 2 +γ 2 |DRR-DRR0| 2 Here, the first, second, and third terms on the right-hand side of evaluation index J are indices that include at least parameter values ​​corresponding to the deviation from the target cut amount, the deviation from the load in the standard recipe, and the deviation from the rotational speed in the standard recipe, respectively.

[0062] Then, the parameter value calculation unit 45 performs an optimization calculation to minimize the value of the evaluation index J and determines the parameter values ​​of the dresser (dresser load and rotation speed) in each scan area. A quadratic programming method can be used for the optimization calculation, but convergence calculations using simulation or PID control may also be used.

[0063] In the above evaluation index J, λ and γ are predetermined weighting values ​​(coefficients) that can be changed as appropriate while using the same polishing pad. By changing these weighting values, the indicators that should be emphasized can be adjusted as appropriate according to the characteristics of the polishing pad and dresser and the operating conditions of the equipment. For example, the parameter value related to the load of the dresser (ΔDRP 2 =|DRP-DRP0| 2 Rather than the weight λ of ), the parameter value related to the dresser rotation speed (ΔDRR 2 =|DRR-DRR0| 2 The weight γ of ) may be increased. This can suppress the dresser from digging into the polishing material.

[0064] In this way, by optimizing the load (pressure) and rotation speed of the dresser, it becomes possible to control the profile of the polishing material even when there are constraints that prevent the dresser's movement speed from being changed.

[0065] The setting input unit 46 is an input device such as a keyboard or mouse, and is used to input various parameters such as the values ​​of each component of the dressing model matrix S, the setting of constraint conditions, the cut rate update cycle, and the parameter value update cycle. The memory 47 stores data for the program that operates each component of the dressing monitoring device 35, as well as various data such as the values ​​of each component of the dressing model matrix S, the target profile, the weighting values ​​of the evaluation index J, and the set values ​​of the dresser's movement speed, load, and rotation speed.

[0066] Figure 7 is a flowchart showing the processing procedure for controlling the parameter values ​​of the dresser. When it is detected that the polishing pad 11 has been replaced (step S11), the dress model setting unit 41 derives a dress model matrix S, taking into account the parameters for the cut rate model, dresser diameter, and scan speed control (step S12). Note that if the same type of pad is used, the dress model matrix can be used continuously.

[0067] Next, it is determined whether to calculate the reference values ​​for the dresser (reference load and / or reference rotation speed) (whether an input indicating that reference value calculation should be performed has been made by the setting input unit 46) (step S13). If the reference values ​​are to be calculated, the parameter value calculation unit 45 sets the load and rotation speed of the dresser in each scan area so that the following evaluation index J is minimized, based on the target cut amount U0 of the dresser and the pad wear amount U in each monitor area (step S14). The calculated reference values ​​may be set as initial values.

[0068] J=|U-U0| 2 +λ 2 |DRP-DRP0| 2 +γ 2 |DRR-DRR0| 2 Subsequently, as the wafer W is polished, the polishing pad 11 is dressed, and the height of the polishing surface 11a (pad height) is measured by the pad height sensor 32 (step S15). Then, it is determined whether the conditions for acquiring the base profile (for example, polishing a predetermined number of wafers W) have been met (step S16), and if the conditions are met, the base profile calculation unit 42 calculates the target profile of the pad height at the time of convergence (base profile) (step S17).

[0069] Subsequently, as the wafer W is polished and the polishing pad 11 is dressed, the pad height sensor 32 measures the height of the polishing surface 11a (pad height) (step S18). Then, it is determined whether a predetermined cut rate calculation cycle (for example, polishing a predetermined number of wafers W) has been reached (step S19), and if so, the cut rate calculation unit 43 calculates the cut rate of the dresser in each scan area (step S20).

[0070] Step S21 determines whether the dresser parameter value update cycle (for example, polishing a predetermined number of wafers W) has been reached. If it has been reached, the parameter value calculation unit 45 optimizes the parameter values ​​(dresser load and rotation speed) in each scan area so that the evaluation index J is minimized (Step S22). The parameters are then updated to the optimized values ​​(Step S23). After this, the process returns to Step S18 and is repeated until the polishing pad 11 is replaced.

[0071] The above describes an example of optimizing the dresser load (pressure) and rotation speed by determining the parameter values ​​in each scan area so that the evaluation index, which includes at least parameter values ​​corresponding to 1) deviation from the target cut amount, 2) deviation from the load in the standard recipe, and 3) deviation from the rotation speed in the standard recipe, is minimized. However, the monitoring target is not limited to the polishing pad height; the surface roughness of the polishing pad can also be measured and the dresser load (pressure) and rotation speed that makes the surface roughness uniform can be calculated. In this case, the following formula may be used as the evaluation index. J = |Ra - Ra0| 2 +λ 2 |DRP-DRP0| 2 +γ 2 |DRR-DRR0| 2 Here, Ra0 is the arithmetic mean roughness of the dresser based on the reference recipe set for each scan area, and Ra is the arithmetic mean roughness of the dresser in each scan area. The embodiments described above are intended to enable persons with ordinary skill in the art to carry out the present invention. Various modifications of the above embodiments can be made naturally by those skilled in the art, and the technical idea of ​​the present invention can be applied to other embodiments as well. The present invention is not limited to the embodiments described and should be interpreted in the broadest sense according to the technical idea defined by the claims. [Explanation of symbols]

[0072] 10 polishing units 11 Polishing pads 14 Dressing Unit 23 Dresser 26 Dresser Arm 32 Pad height sensor 35 Dressing monitoring device 41 Dress Model Setting Section 42 Base Profile Calculation Unit 43. Cut Rate Calculation Unit 44 Evaluation Metric Creation Department 45 Parameter Value Calculation Unit S1~S7 Scan Area M1-M10 Monitor Area

Claims

1. A substrate polishing apparatus that polishes a substrate by sliding it against an abrasive member, A dresser that dresses the polishing member by oscillating on the polishing member, the dresser having adjustable load and rotation speed in a plurality of scan areas set on the polishing member along the direction of oscillation, A height detection unit measures the surface height of the polishing member in a plurality of pre-set monitoring areas on the polishing member along the oscillation direction of the dresser, A dress model matrix creation unit that creates a dress model matrix defined from multiple monitor areas, scan areas, and dress models, An evaluation index creation unit calculates a height profile prediction value using the dressing model and the oscillation speed or residence time of the dresser in each scan area, and creates an evaluation index based on the difference from the target value of the height profile of the polishing member. A calculation unit that calculates the load and rotational speed of the dresser in each scan area of ​​the dresser based on the evaluation index, A substrate polishing apparatus equipped with the following features.

2. The dressing of the polishing member is performed by simultaneously changing the load and rotation speed of the dresser calculated by the calculation unit. The substrate polishing apparatus according to claim 1.

3. The dressing of the polishing member is performed while the oscillation speed of the dresser is constant. The substrate polishing apparatus according to claim 1.

4. The evaluation index includes a first parameter corresponding to the load of the dresser and a second parameter corresponding to the rotational speed of the dresser. The evaluation index creation unit creates the evaluation index such that the weight of the second parameter is greater than the weight of the first parameter. The substrate polishing apparatus according to claim 1.

5. A substrate processing apparatus comprising a substrate polishing apparatus according to any one of claims 1 to 4.

6. A method for adjusting the load and rotation speed in a plurality of scan areas set on a polishing member, along the direction of oscillation of a dresser that dresses a polishing member by oscillating on the polishing member for polishing a substrate, The surface height of the polishing member is measured in a plurality of pre-set monitoring areas on the polishing member along the oscillation direction of the dresser, Creating a dress model matrix defined from multiple monitor areas, scan areas, and dress models, The method involves calculating a predicted height profile using the dressing model and the oscillation speed or residence time of the dresser in each scan area, and creating an evaluation index based on the difference from the target value of the height profile of the polishing member. Based on the evaluation index, the load and rotational speed of the dresser in each scan area of ​​the dresser are calculated, Methods that include...

7. A program that causes a computer to perform the method described in claim 6.

8. A computer-readable storage medium storing the program described in claim 7.

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