JP2016020017A - Grinding unit and grinding processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide grinding processing equipment and component devices thereof which can more simply and highly accurately adjust an angle of a rotary shaft of a grinding surface in relation to a ground surface of a substrate.SOLUTION: A grinding head section includes a grinding stone 20 and an inclination adjustment mechanism for inclining a rotary shaft of the grinding stone 20 so as to change a relative angle of a grinding stone grinding surface in relation to a ground surface of a substrate W. The inclination adjustment mechanism includes: an adjuster 24 arranged at one intersection point position of two intersection points in which a horizontal line passing a center of the grinding stone grinding surface and a grinding stone grinding surface peripheral edge intersect each other; and adjusters 22 and 23 which are arranged at the grinding stone grinding surface peripheral edge and are arranged at positions forming each equal spaced angle with the center of the grinding stone grinding surface by using the arrangement position of the adjuster 24 as a reference. The inclination adjustment mechanism determines change amount for changing the relative angle of the grinding stone grinding surface in relation to the ground surface on the basis of the shape of the ground surface processed most recently, and operates only the adjuster 24 of the adjusters 22, 23 and 24 according to the change amount.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a grinding unit and a grinding processing apparatus for grinding and flattening a substrate such as a semiconductor wafer or a glass substrate.

2. Description of the Related Art In recent years, in the semiconductor device manufacturing process, with the high integration of a substrate, a technology for planarizing the surface of the substrate has become increasingly important. Among the planarization techniques, the most important technique is chemical mechanical polishing (CMP). In this chemical mechanical polishing, a substrate is slid onto the polishing pad while supplying a polishing liquid containing abrasive grains such as silica (SiO ₂ ) onto the grinding pad using a polishing processing apparatus (also called a polishing apparatus). Polishing treatment is performed in contact. Similarly, high precision is also required for a grinding substrate which is a pre-processing of CMP processing.

  GBIR (Global Backsurface-referenced Ideal plane / Range), SFQR (Site Frontsurface referenced) are used as evaluation indices (flatness evaluation indices) of the flatness of the surface to be ground (hereinafter referred to as “surface to be ground”). least sQuares / Range). GBIR is a back-referenced global flatness index and is used to evaluate the flatness of the entire wafer surface defined excluding the peripheral edge. GBIR is defined as the width of the maximum and minimum thickness deviation of the surface of the semiconductor wafer with respect to the reference surface when the back surface of the semiconductor wafer is the reference surface.

  From the viewpoint of improving the quality of the substrate, there is a wafer grinding apparatus disclosed in Patent Document 1. This grinding apparatus has a grinding unit equipped with a grinding wheel, an inclination adjusting mechanism for inclining the grinding unit relative to the surface to be ground of the wafer, and grinding condition storage means. Conditions and the inclination angle of the grinding means corresponding to each grinding condition are stored in the grinding condition storage means, and the inclination angle corresponding to the grinding condition is selected by selecting the grinding condition when grinding the wafer. It is to be done.

  According to this grinding apparatus, even if an inexperienced worker does not require skill, if the grinding means is tilted along the inclination angle selected by the grinding condition storage means, the wafer thickness is made uniform. It can be finished.

  Further, there is a wafer grinding apparatus disclosed in Patent Document 2 from the viewpoint of inclining the angle of the rotating shaft on the holding means (for example, chuck table) side that holds the wafer.

JP 2009-90389 A JP 2008-258554 A

However, in the grinding apparatus disclosed in Patent Document 1, the tilt adjustment mechanism controls the grinding unit to tilt in the front and rear and left and right directions so that a desired tilt is obtained. It becomes difficult to control the fine tilt of the order. As a result, there remains a problem that GBIR or the like cannot be improved in a specific portion on the surface to be ground.
Moreover, in the grinding apparatus disclosed in Patent Document 2, it is necessary to provide an inclination adjusting means for each chuck table that holds a wafer. This increases the complexity of the apparatus and the manufacturing cost, and increases the cost for each chuck table. Therefore, there is a problem that productivity cannot be improved in the single-wafer compatible type.
Furthermore, in this grinding machine, the angle of the grindstone rotating shaft is adjusted by three adjusters arranged at 120 ° intervals. However, the geometric relationship between the three points is complicated, and advanced control technology is required. Yes, there remains a problem that sub-micron control is difficult with this method.

  The present invention provides a grinding apparatus capable of adjusting the angle of a rotation axis of a grindstone grinding surface (hereinafter referred to as “grinding surface”) with respect to a surface to be ground of a substrate more easily and with high accuracy, and a component apparatus thereof. Is the main issue. Also provided are a grinding apparatus capable of improving GBIR and the like on the substrate surface, and a component apparatus therefor.

  A grinding unit of the present invention that solves the above problems is a grinding unit provided in a grinding processing apparatus having a holding mechanism that holds a substrate to be ground and rotates horizontally, and has a rotating grinding surface. A grinding means for sliding a part of the ground surface in sliding contact with a part of the ground surface of the substrate held by the holding mechanism; and a rotating shaft of the grinding means is inclined to the ground surface. An adjustment mechanism that changes a relative angle of the grinding surface, and the adjustment mechanism is one of two intersections at which a horizontal line passing through the center of the grinding surface intersects with the periphery of the grinding surface. A first adjusting means provided at the intersection point; and a position provided at a peripheral edge of the grinding surface, and at an angle of equal intervals with respect to a center of the grinding surface with respect to a deployment position of the first adjusting means. Deployed second and third adjusting means; The amount of change for changing the angle is determined based on the shape of the surface to be ground of the substrate that has been most recently ground, and the first of the first, second, and third adjustment means. Only one adjusting means operates according to the amount of change and changes the relative angle.

  Further, the grinding processing apparatus of the present invention is a grinding processing apparatus having a grinding unit and a holding mechanism that holds the substrate to be ground and rotates horizontally, and the grinding unit has a rotating grinding surface. A grinding means for slidingly contacting a part of the ground surface with a part of the ground surface of the substrate held by the holding mechanism, and tilting a rotation shaft of the grinding means An adjustment mechanism that changes a relative angle of the grinding surface with respect to a surface, and the adjustment mechanism includes a horizontal line that passes through a center of the grinding surface and a crossing point of a peripheral edge of the grinding surface. A first adjusting means provided at one of the intersecting points; and provided at a peripheral edge of the grinding surface, and each of the first adjusting means has an equally spaced angle with respect to the center of the grinding surface with reference to the provided position of the first adjusting means. Second and third adjusting means arranged in position; The amount of change for changing the angle is determined based on the shape of the surface to be ground of the substrate that has been most recently ground, and the first of the first, second, and third adjustment means. Only one adjusting means operates according to the amount of change and changes the relative angle.

  According to the grinding unit of the present invention, the angle of the rotation axis (grindstone grinding axis) of the grinding surface with respect to the ground surface of the substrate can be adjusted more simply and with high accuracy. Thereby, further improvement of GBIR etc. of a substrate surface can be aimed at.

The schematic block diagram of the grinding processing apparatus which concerns on this embodiment. The figure for demonstrating the structure for adjusting the inclination of a grinding head part. (A), (b), (c) is a figure for demonstrating the geometric structure of the grindstone and a board | substrate at the time of a grinding process. The figure which shows the specific example of the sliding contact position of a grindstone and a board | substrate at the time of a grinding process, and the arrangement | positioning relationship of an adjuster. (A), (b) is a figure for demonstrating an example of the height adjustment mechanism of an adjuster, and the thickness measurement point of the board | substrate after grinding. (A), (b), (c), (d) is a figure for demonstrating that the grinding surface of a general grinding surface and the to-be-ground surface of the board | substrate W are formed in (omega) shape. (A), (b), (c) is a figure for demonstrating the feedback correction | amendment which a grinding processing apparatus performs. Explanatory drawing of the main control procedures by the control part at the time of performing a grinding process.

  Embodiments of the present invention will be described below with reference to the drawings.

The single wafer processing type grinding processing apparatus described in the present embodiment targets a substrate such as a semiconductor wafer or a glass substrate as a grinding target. In this specification, the surface of this substrate is referred to as a circular or substantially circular surface to be ground. Moreover, it is called a grindstone grinding surface (grinding surface) with respect to the surface to be ground of the substrate.
In addition, the grinding processing apparatus is provided with a turntable on which a plurality of chuck tables that rotate horizontally by sucking and holding a substrate to be ground are mounted, and a grindstone (cup-type grindstone) that serves as a grinding member is attached. On the other hand, it is assumed that it has a grinding head portion that moves in the vertical direction while rotating the grindstone.
In the grinding processing apparatus, for example, the grinding unit descends toward the substrate W and presses the grindstone against the surface to be ground of the substrate W. Then, the surface to be ground is ground by rotating the chuck table and the grindstone while supplying the grinding liquid to the surface to be ground. Hereinafter, embodiments of the grinding processing apparatus will be described.

[Embodiment]
FIG. 1 is a schematic configuration diagram of a grinding processing apparatus according to the present embodiment. 1 is roughly divided into a grinding mechanism (grinding unit 2) including a grinding head portion 21 to which a grindstone for grinding a substrate is mounted, and a substrate to be ground by suction. A holding mechanism including a chuck table 31 is provided. Each of these mechanisms is provided on a base 10 as shown in FIG.
The grinding unit 2 includes a grinding head portion 21 for mounting the grindstone 20 at one end thereof, and adjusters 22, 23, 24 for adjusting the inclination of the grinding head portion 21 through a flange portion 21 a formed on the grinding head portion 21. An adjuster base 25 provided with an adjuster, a back plate 26 that holds the adjuster base 25, and a bush rod 27 connected to the back plate 26 are configured. Further, the back plate 26 is formed with a constricted portion 28 serving as a fulcrum of inclination when setting a heel angle described later. The bush rod 27 is connected to a heel angle adjusting mechanism (not shown), and is configured to be able to swing the back plate 26 forward or backward (Y-axis direction) in the direction of the grinding head portion 21 with the constricted portion 28 as a fulcrum. Is done. Moreover, the grinding head part 21 is provided with the feed mechanism for making the grindstone 20 cut into the to-be-ground surface.
In the description of the present embodiment, the description will be given on the assumption that the initially set heel angle remains fixed at the optimum angle.

The holding mechanism includes a turntable 30 and a chuck table 31 provided on the turntable 30 by a predetermined number (three in FIG. 1) for holding the substrate W by suction. The turntable 30 is rotated by a driving force transmitted from a motor (not shown), and moves the substrate W to be processed, which is chucked and held by the chuck table 31, to a predetermined grinding position.
The chuck table 31 is, for example, a vacuum suction type chuck table connected to a suction mechanism (not shown). Further, in the grinding processing apparatus 1, a nozzle (not shown) for supplying a grinding liquid toward the surface to be ground of the substrate W, a motor (not shown) for rotating the grindstone 20 and the chuck table 31 horizontally, A control unit 40 including a motor (not shown) for moving the grinding head unit 21 in the vertical direction, a grinding fluid supply mechanism (not shown) connected to the nozzle, and a computer for controlling each drive unit including the motor. It is comprised including.

  The grindstone 20 is, for example, a grindstone formed in a columnar shape or a pan shape (cup shape), and the radius thereof is larger than the radius of the surface to be ground of the substrate W. Further, the grindstone 20 is formed including, for example, diamond abrasive grains, and the content of abrasive grains per unit volume of the grindstone, the grain diameter of the abrasive grains, the density and hardness of the grindstone, etc., as appropriate depending on the substrate W to be treated Is determined. Further, in this mechanism, the rotational speed of the grindstone 20 and the chuck table 31 is changed, and the relative grinding speed in the substrate W surface can be adjusted. Thus, the structure including the grindstone 20 and the grinding head portion 21 functions as a grinding means. In the grinding apparatus 1, the grinding process is performed by bringing a part of the ground surface into sliding contact with a part of the ground surface of the substrate W.

The control unit 40 controls the rotation speed of the grinding wheel spindle motor, the feed speed of the grinding wheel spindle (Z axis), the rotation speed of the chuck table, the tilt control of the grinding head section 21, the positioning of the nozzle, and the supply start or stop control of the grinding fluid from the nozzle. The main control is the supply amount control per unit time of the grinding fluid sprayed from the nozzle, the start and stop of the motor. The rotational force of the motor controlled by the control unit 40 is transmitted to the chuck table 31 via a drive unit (not shown). As a result, the chuck table 31 rotates horizontally or stops rotating.
The rotational force of the motor is also transmitted to the grinding head unit 21 via a drive unit (not shown) (for example, a universal joint). As a result, the grindstone 20 mounted on the grinding head portion 21 rotates horizontally or stops rotating. Further, signal processing from the thickness detection sensor and a control command to the adjuster 24 are executed.

  Here, the rotation direction of the chuck table 31 and the rotation direction of the grindstone 20 are generally the same direction. The grinding liquid is supplied from the nozzle toward the surface to be processed of the substrate W at the grinding processing position for a predetermined time in a state where the rotation speed of the chuck table 31 reaches a predetermined value under the control of the control unit 40. Details of the control procedure by the controller 40 will be described later.

  Next, the structure for adjusting the inclination of the grinding head part 21 with which the grinding processing apparatus 1 is provided is demonstrated in detail. FIG. 2 is a diagram for explaining a configuration for adjusting the inclination of the grinding head portion 21.

  As shown in FIG. 1, the grinding head portion 21 is, for example, a flange portion extending in the circumferential direction (perpendicular to the rotation axis of the grinding surface) at a predetermined portion on the outer surface of the casing formed in a columnar shape. 21a is formed. As shown in FIG. 2, each adjuster is arranged such that the upper bottom surface of each adjuster is in contact with the lower bottom surface of the flange portion 21 a and the lower bottom surface of each adjuster is in contact with the upper bottom surface of the adjuster base 25. Each adjuster arranged in this way constitutes an inclination adjusting mechanism. The adjuster 24 functions as first adjusting means. The adjuster 23 functions as a second adjusting unit, and the adjuster 22 functions as a third adjusting unit. In addition, as shown in FIG. 2, each adjuster and the grinding head unit 21 interfere with each other when adjusting the inclination by arranging the adjusters so that the center of the upper bottom surface of each adjuster is positioned at the periphery of the flange portion 21a. Can be prevented.

Further, the adjuster base 25 on which the adjusters 22, 23, and 24 are provided has a hole into which the grinding head portion 21 is inserted, and the grinding head portion 21 is inclined to a predetermined inclination via the adjusters 22, 23, and 24. It is comprised so that it can hold | maintain (X-axis direction).
Each adjuster 22, 23 has a zero backlash ball seat bearing (not shown), and is connected to a socket (not shown) provided at a predetermined portion of the flange 21a. Is configured to be able to act as a fulcrum when pushing up (Z-axis direction) upward or down. Thereby, the relative height of the collar part 21a with respect to the adjuster base 25, that is, the distance between the collar part 21a and the adjuster base 25 can be relatively changed at the place where each adjuster is provided.

  The adjusters 22 and 23 are fixed at a predetermined height so as to be a reference value (reference distance) for the distance between the flange 21a and the adjuster base 25 in the tilt adjustment. That is, the adjusters 22 and 23 support the flange portion 21a at each deployment position, and the adjuster 24 pushes the flange portion 21a upward or pulls it downward with the supported portion of the flange portion 21a as a fulcrum. Therefore, the adjuster 24 includes a height adjusting mechanism that adjusts the distance between the flange portion 21a and the adjuster base 25 in accordance with the latest grinding result to be described later. Details of the height adjustment mechanism of the adjuster 24 will be described later with reference to FIG.

In this way, the adjuster 24 changes the distance between the flange portion 21a and the adjuster base 25 to change the inclination of the grinding head portion 21, that is, the inclination of the grinding surface relative to the surface to be ground of the substrate W. And the inclination can be adjusted. Further, for example, when grinding a plurality of substrates W continuously, only the height adjusting mechanism of the adjuster 24 is operated to adjust the inclination of the grinding surface until a series of processing is completed.
Hereinafter, the positional relationship between the substrate W and the grindstone 20 during the grinding process will be described in detail with reference to FIGS.

  FIG. 3 is a diagram for explaining the geometric configuration of the grindstone 20 and the substrate W during the grinding process. In FIG. 3, for convenience of explanation, the grindstone 20 (grinding surface) is schematically represented in a ring shape. 3A is a plan view, FIG. 3B is a front view when viewed from the B direction shown in FIG. 3A, and FIG. 3C is a side view when viewed from the C direction. It is.

In the grinding processing apparatus 1 according to the present embodiment, a processing position is a position where a part of the surface to be processed of the substrate W and a part of the grinding surface of the grindstone 20 overlap as shown in FIG. Is set.
Further, the rotation axes of both the grindstone 20 and the substrate W are in different positions in the X-axis and Y-axis directions, as shown in FIGS.
As shown in FIG. 3B, the inclination adjustment value β (inclination angle β) is the relative inclination of the grinding surface with respect to the surface to be ground of the substrate W, and is adjusted by the adjuster 24 as described above. As shown in FIG. 3C, the heel angle is set when the bush rod 27 connected to the heel angle adjusting mechanism (not shown) tilts the back plate 26 in the Y-axis direction. By providing the heel angle α, it is possible to simplify the accuracy adjustment near the rotation center and the outer periphery of the substrate W.

FIG. 4 is a diagram showing a specific example of the geometric configuration of the grindstone 20 and the substrate W during the grinding process. In FIG. 4, the radius of the grindstone 20 is indicated as Gr, and the radius of the substrate W is indicated as Wr.
As shown in FIG. 4, in the turntable 30 of FIG. 1, when the center (O) of the grindstone 20 is the coordinate origin (0, 0), the center (Ws) of the substrate W is coordinates: X = Gr · SIN30. The rotation is stopped at the position of [°], Y = −Gr · COS 30 [°], and then the grinding of the surface to be ground is started. In the case of such control, the adjuster 24 is arranged on the Y = 0 line (X = R) on the periphery of the grinding surface. Further, the adjuster 22 is disposed at a position specified by X = −Gr · SIN 30 [°] and Y = Gr · COS 30 [°] on the periphery of the grinding surface. The adjuster 23 is disposed at a position specified by X = −Gr · SIN30 [°] and Y = −Gr · COS30 [°] on the periphery of the grinding surface.
Further, as described above, in the grinding processing apparatus 1 according to the present embodiment, the heel angle is fixed at a preset optimum angle, and is not operated until a series of processing ends. That is, only the height adjustment mechanism of the adjuster 24 is operated to adjust the inclination of the grinding surface in the X-axis direction.

The relationship between the positions of the adjusters shown in FIG. 4 is merely an example, and the adjusters can be disposed at mirror facing positions with reference to the Y-axis direction including the center of the grindstone 20.
For example, in FIG. 4, the case where the size of the grinding surface is formed to be approximately the same size as the size of the surface to be ground of the substrate W is taken as an example. In this case, the adjuster 24 is disposed at one of the two intersections where the grinding surface periphery and the surface to be ground intersect when the grindstone 20 and the substrate W are in sliding contact with each other. Further, the adjuster 23 is deployed at the other one of the intersection positions different from the deployment position of the adjuster 24. The adjuster 22 is a position where the bisector of the line segment connecting the deployment position of the adjuster 24 and the deployment position of the adjuster 23 intersects with the periphery of the grinding surface, and an intersection point relatively far from the adjuster 24 and the adjuster 23. Deploy in position. Such a geometric configuration can also be adopted. That is, the adjuster 24 may be disposed at one of the two intersections where the horizontal line passing through the center of the grinding surface and the periphery of the grinding surface intersect. Further, the adjusters 22 and 23 may be disposed on the periphery of the grinding surface at a position where each of the adjusters 22 and 23 forms an equally spaced angle with respect to the center of the grinding surface on the basis of the position where the adjuster 24 is disposed.
Hereinafter, the height adjusting mechanism of the adjuster 24 will be described in detail.

FIG. 5 is a view for explaining an example of the height adjusting mechanism of the adjuster 24. FIG. 5A is a diagram schematically showing the configuration of this tilt adjustment mechanism, and FIG. 5B shows an example of a thickness detection point that is performed on the substrate that has been subjected to the most recent grinding process. FIG.
The height adjustment mechanism (24a) of the adjuster 24 includes an arm 50, rollers 51 and 52, coil springs 53 and 54, a slider 55 formed in a wedge shape, and a ball screw type for moving the slider 55 by a predetermined amount in a predetermined direction. The feed mechanism 56 is included. The ball screw type feeding mechanism 56 is electrically connected to the sensor control unit 58. The sensor control unit 58 performs a predetermined process based on the detection result (measurement result) of the thickness detection sensor 57 for detecting the thickness of the substrate after the grinding process. The processing result is transmitted to the ball screw type feed mechanism 56.

  The arm 50 is configured to be swingable in conjunction with the slide operation of the slider 55 via the roller 52. The thickness detection sensor 57 uses, for example, a spectral interference type thickness sensor that can measure the thickness between the front and back sides only by measurement from the surface side of the substrate, and measures the thickness of the surface to be ground for each detection point. Measure the thickness of the surface to be ground. That is, the thickness shape of the surface to be processed after grinding is measured by the thickness detection sensor 57. Further, the thickness detection sensor 57 is connected to a drive mechanism (not shown) and is configured to be movable to each detection point shown in FIG. 5 (for example, 17 points indicated by mesh circles in the figure). Note that the thickness shape of the substrate W that has been ground most recently is configured to be measured while being held on the chuck table 31, for example, or configured to be measured after being taken out from the chuck table 31. be able to.

  The adjuster 24 is formed with a protrusion 60 at a predetermined portion on the outer peripheral surface thereof. As shown in FIG. 5, the upward or downward swinging motion of the arm 50 is transmitted to the protrusion 60 via the roller 51. As a result, the distance between the flange 21 a and the adjuster base 25 is adjusted via the adjuster 24. This adjustment is performed by the sensor control unit 58 based on the measurement result at each detection point as shown in FIG. To decide. The ball screw type feed mechanism 56 moves the slider 55 in the horizontal direction according to the accepted inclination angle β. The arm 50 swings upward or downward in conjunction with the amount of movement of the slider 55. In this way, the grinding processing apparatus 1 performs feedback correction for adjusting the inclination according to the latest grinding result.

Each detection point is set according to the size of the substrate to be detected, the inclination adjustment accuracy of the desired grinding head unit 21, and the like. The relative deployment positions of the roller 51 and the roller 52 with respect to the arm 50 are determined in accordance with the inclination resolution accuracy of the grinding head unit 21, the feed accuracy of the ball screw type feed mechanism 56, and the like. Further, the material of the coil springs 53 and 54, the spring coefficient, etc. are determined according to the grinding wheel grinding resistance.
As a result, the height adjustment mechanism of the adjuster 24 is more accurate than the conventional tilt adjustment performed by the ball screw shaft and the nut, in which the adjustment accuracy is affected by, for example, “backlash” generated between components. The inclination of the grinding surface according to the surface (surface to be ground) profile can be adjusted. This point will be described in detail with reference to FIGS.

FIG. 6 is a diagram for explaining that the ground surface of the substrate is formed in a ω shape in the grinding process.
6A is a plan view showing a grinding model when a heel angle is given to the grindstone rotating shaft, FIG. 6B is a view (front view) when viewed from the arrow B, and FIG. 6C is an arrow C. It is a figure (side view) when it sees from. In this configuration, if only the radius part of the substrate is ground without rotating the substrate, the ground portion will have a concave cross-sectional shape, but in a normal grinding state, the substrate is also rotated, so the surface to be ground after grinding is An axisymmetric ω shape as shown in FIG.

  In addition, height Hz shown in FIG.6 (d) represents the difference of the minimum thickness of the board | substrate after a grinding process, and the thickness of a center convex part. This height Hz depends on a preset heel angle α and inclination angle β. However, even in the case where a heel angle is provided and geometric adjustment is performed near the rotation center and the outer periphery, in a grinding process using a general grinding head, there is a large variation in the height Hz. May occur.

FIG. 7 is a diagram for explaining feedback correction performed by the grinding processing apparatus 1.
For example, FIG. 7A shows a case where the center thickness of the substrate after the grinding process becomes thicker than the thickness of the peripheral edge, and the difference is indicated as “+ Cz”. FIG. 7B shows a case where the center thickness of the substrate after the grinding process is thinner than the peripheral thickness, and the difference is indicated as “−Cz”. As described with reference to FIG. 6, the difference Cz may vary in the surface to be ground after grinding for each substrate. FIG. 7C shows an ideal surface to be ground (β = 0) having the same thickness at the center and the periphery after grinding, and Hz is determined by the heel angle α and the grindstone radius Gr. Is done.

For example, when the surface to be processed of the substrate that has been most recently ground is in a state as shown in FIG. 7A, the central portion is compared with the state of the ideal surface to be ground shown in FIG. It can be seen that the grinding amount is small. Further, when the surface to be processed of the substrate that has been subjected to the most recent grinding processing is in a state as shown in FIG. 7B, the central portion is compared with the state of the ideal surface to be ground shown in FIG. It can be seen that the amount of grinding is large.
In the grinding processing apparatus 1 according to the present embodiment, the heel angle is not subject to angle control, and the inclination of the grinding surface is adjusted by the height adjustment mechanism of the adjuster 24 based on the detection result of the thickness detection sensor 57, thereby grinding. Suppresses variations in the surface to be ground later. At that time, the amount of change for changing the angle of the grinding surface, that is, the inclination angle β used for the inclination adjustment can be calculated by the following equation (1).

  β = ± Cz / 2 / R (R is the radius of the substrate W) (1)

  By performing feedback correction by the height adjustment mechanism of the adjuster 24 based on the inclination angle β determined in this way, it is possible to easily and precisely control the fine inclination of the grinding head portion 21 in the submicron order. .

[Control procedure for grinding]
Next, the grinding processing procedure by the grinding processing apparatus 1 of this embodiment will be described. FIG. 8 is an explanatory diagram of main control procedures by the control unit 40 when executing the grinding method.
The control unit 40 starts control upon receiving an input of a start instruction by the operator of the grinding processing apparatus 1 (S100). After predetermined initial processing, suction holding of the substrate W to the chuck table 31 by the holding mechanism is started.

The control unit 40 starts suction by the suction mechanism (S101). The control unit 40 determines whether a specified time (first specified time) has elapsed since the start of suction (S102). Whether or not the first specified time has elapsed is determined by a first timer (not shown).
When it is determined that the specified time has elapsed (S102: Yes), the control unit 40 rotates the turntable 30 and moves the substrate W to be ground to the grinding start position (S103). Otherwise (S102: No), the suction is continued until the specified time has elapsed.

  Further, the control unit 40 issues an instruction to the height adjustment mechanism of the adjuster 24, starts thickness measurement for each detection point of the substrate that has been subjected to the latest grinding process, and performs tilt adjustment (feedback correction) (S104). . Thereafter, the control unit 40 determines whether or not the feedback correction according to the measurement result is completed (S105). If it is determined that the process has been completed (S105: Yes), the process proceeds to step S106. If not (S105: No), it waits until feedback correction is completed.

  The controller 40 gives an instruction to a motor (not shown) to start rotation of the chuck table 31 and the grindstone 20 at the start position of the grinding process (S106).

After instructing rotation start of the chuck table 31 and the grindstone 20, the control unit 40 instructs positioning of the nozzle and instructs the grinding fluid supply mechanism to start supplying the grinding fluid (S107). As a result, the grinding liquid is supplied from the nozzle toward the surface to be ground.
The control unit 40 instructs the descent speed: −Vz of the grinding head unit 21 after the start of supplying the grinding liquid to bring the grinding surface and the surface to be ground into sliding contact. In this way, grinding of the surface to be ground is started.
When the control unit 40 detects that the specified grinding time (second specified time) has elapsed by a second timer (not shown) (S108: Yes), it instructs the grinding fluid supply mechanism to stop supplying the grinding fluid. Then, the rising speed of the grinding head unit 21: + Vz is instructed (S109). Thereafter, the control unit 40 instructs a motor (not shown) to stop the rotation of the chuck table 31 and the grindstone 20 (S110).

  The control unit 40 rotates the turntable 30 again to separate the ground substrate W from the grinding position. The control unit 40 then releases (ends) the suction holding in response to the fact that the ground substrate W has moved to the transport position for the next process (S111). Thereby, a series of grinding processes are completed.

  Here, the case where the feedback correction (steps S104 and S105) is performed before the start of the grinding process for the next substrate has been described as an example. In addition, while performing the grinding process on the next substrate, for example, feedback correction for adjusting the inclination between the start of the descent of the grinding head unit 21 and the stop of the descent can be performed. As described above, the feedback correction execution timing can be set in consideration of the characteristics of the substrate to be ground, the total number of substrates to be ground continuously, the time required for grinding a single substrate, and the like.

As described above, the grinding apparatus 1 according to the present embodiment calculates the inclination angle β based on the state of the surface to be ground of the substrate that has been most recently ground, and adjusts the inclination of the grinding head portion 21 based on this (feedback correction). ) This adjustment is performed by the height adjustment mechanism of the adjuster 24. As a result, it is possible to control a fine tilt on the order of submicron, and it is possible to more easily and accurately prevent the occurrence and variation of grinding unevenness of the substrate. Moreover, further improvement of GBIR on the substrate surface can be achieved.
Furthermore, by providing the adjusting mechanism on the grinding mechanism side, it is possible to reduce the cost of manufacturing the apparatus by simplifying the mechanism as compared with the case where the adjusting mechanism is provided on the holding mechanism side.

  The embodiment described above is for explaining the present invention more specifically, and the scope of the present invention is not limited to these examples.

  DESCRIPTION OF SYMBOLS 1 ... Grinding processing apparatus, 2 ... Grinding unit, 10 ... Base, 20 ... Grinding wheel, 21 ... Grinding head part, 21a ... Gutter part, 22, 23, 24 ... Adjuster, 24a: Adjuster 24 height adjustment mechanism, 25: Adjuster base, 26: Back plate, Bush rods 27, 28 ... Constriction, 30 ... Turntable, 31 ... -Chuck table, 40 ... control unit, 50 ... arm, 51, 52 ... roller, 53, 54 ... coil spring, 55 ... slider, 56 ... ball screw type feed mechanism, 57... Thickness detection sensor, 58... Sensor control unit, 60.

Claims (7)

A grinding unit provided in a grinding processing apparatus having a holding mechanism that holds a substrate to be ground and rotates horizontally,
A grinding means that has a rotating grinding surface, and that slidably contacts a partial region of the ground surface with a partial region of the ground surface of the substrate held by the holding mechanism;
An adjustment mechanism that changes the relative angle of the grinding surface with respect to the surface to be ground by inclining the rotation axis of the grinding means,
The adjustment mechanism is
First adjusting means arranged at one of the two intersections where the horizontal line passing through the center of the grinding surface and the periphery of the grinding surface intersect;
Second and third adjusting means provided on the periphery of the grinding surface and provided at positions that are equally spaced with respect to the center of the grinding surface with reference to the position of the first adjusting means; It is composed including
The amount of change for changing the angle is determined based on the shape of the surface to be ground of the substrate that has been most recently ground, and only the first adjustment unit among the first, second, and third adjustment units is the change amount. According to the above, and the relative angle is changed.
Grinding unit. The grinding means includes a line segment connecting the center of the grinding surface and the center of the surface to be ground, and a line segment connecting the deployment position of the first adjustment means and the deployment position of the second adjustment means. Characterized in that a part of the ground surface is slidably contacted with a part of the ground surface to be orthogonal,
The grinding unit according to claim 1. The adjusting mechanism operates only the first adjusting means during the period from the start to the end of the grinding process.
The grinding unit according to claim 1 or 2. The grinding means has a flange extending in a direction perpendicular to the rotation axis,
In the adjusting mechanism, the second and third adjusting means support the collar portion at each deployment position, and the first adjusting means raises the collar portion upward with a portion of the supported collar portion as a fulcrum. The relative angle of the grinding surface with respect to the ground surface is changed by pushing up or pulling down,
The grinding unit according to claim 1, 2 or 3. The first adjusting means moves a slider configured to be movable in the horizontal direction in accordance with the amount of change, and pushes the collar up or down in conjunction with the amount of movement of the slider. It is configured as follows,
The grinding unit according to claim 4. The size of the grinding surface of the grinding means is formed to be approximately the same size as the size of the surface to be ground of the substrate,
The first adjusting means is arranged at one of the two intersections at which the periphery of the grinding surface and the periphery of the surface to be ground intersect when the sliding contact is made,
The second adjusting means is arranged at the other one of the intersection positions different from the deployment position of the first adjusting means,
The third adjustment means is a position where a bisector of a line segment connecting the deployment position of the first adjustment means and the deployment position of the second adjustment means intersects the periphery of the grinding surface, and , Characterized in that it is arranged at an intersection point far from the first and second adjusting means,
The grinding unit according to any one of claims 1 to 5. A grinding processing apparatus having a grinding unit and a holding mechanism that holds a substrate to be ground and rotates horizontally,
The grinding unit is
A grinding means that has a rotating grinding surface, and that slidably contacts a partial region of the ground surface with a partial region of the ground surface of the substrate held by the holding mechanism;
An adjustment mechanism that changes the relative angle of the grinding surface with respect to the surface to be ground by inclining the rotation axis of the grinding means,
The adjustment mechanism is
First adjusting means arranged at one of the two intersections where the horizontal line passing through the center of the grinding surface and the periphery of the grinding surface intersect;
Second and third adjusting means provided on the periphery of the grinding surface and provided at positions that are equally spaced with respect to the center of the grinding surface with reference to the position of the first adjusting means; It is composed including
The amount of change for changing the angle is determined based on the shape of the surface to be ground of the substrate that has been most recently ground, and only the first adjustment unit among the first, second, and third adjustment units is the change amount. According to the above, and the relative angle is changed.
Grinding processing equipment.