Dressing device, dressing method, and chip manufacturing method

Abstract

To provide a dressing device, a dressing method, and a tip manufacturing method capable of suitably controlling relative movement of a dresser board and a grinding wheel in a direction crossing a sliding surface during dressing or a load applied between them during dressing.SOLUTION: The dressing apparatus includes a board holding part that holds the dresser board, a moving part that moves the board holding part and the grindstones relative to each other in a direction intersecting sliding surfaces of the grindstones and the dresser board, and a measuring part that measures a load applied to the dresser board.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for dressing a grinding wheel, and a method for manufacturing inserts using the same. [Background technology]

[0002] Device chips such as integrated circuits (ICs) are essential components in various electronic devices such as mobile phones and personal computers. These chips are manufactured, for example, by thinning a semiconductor wafer on which multiple devices are formed, and then dividing the semiconductor wafer into regions containing individual devices.

[0003] Thinning of a semiconductor wafer as a workpiece is performed, for example, by grinding the backside of the workpiece using a grinding device. This type of grinding device includes, for example, a chuck table that holds the workpiece with its front side facing downward, and a spindle on which a grinding wheel equipped with grinding stones is attached. The grinding wheel is an annular component with multiple grinding stones attached to its underside, and the spindle is a component with the grinding wheel attached to its lower end and rotating together with the grinding wheel.

[0004] Each grinding stone attached to the grinding wheel is, for example, a grinding stone configured with abrasive grains embedded in a bond material. The bond material may be, for example, a vitrified bond containing air bubbles, a resin bond, etc. Abrasive grains such as diamond or cubic boron nitride are dispersed in the bond material to form the grinding stone.

[0005] The workpiece (semiconductor wafer) is thinned in a grinding device, for example, by the following procedure.

[0006] First, the workpiece is held on a holding surface provided on the upper surface of the chuck table. At this time, the workpiece is held with the front surface on which the device is provided facing downward and facing the upper surface (holding surface) of the chuck table. In other words, the workpiece is held with the back surface on which the device is not provided exposed upward.

[0007] A grinding wheel with a grinding stone attached to its underside is positioned above a workpiece with its back side facing up. In this state, the grinding wheel attached to a spindle and the chuck table holding the workpiece each rotate about a vertical axis, and as this rotation occurs, the chuck table and spindle are moved closer to each other in the vertical direction. When the grinding stone attached to the underside of the rotating grinding wheel comes into contact with the backside of the workpiece held on the top surface of the chuck table, the abrasive grains exposed on the underside of the grinding stone grind the backside of the workpiece.

[0008] By performing this process continuously while moving the chuck table and spindle relative to each other in the vertical direction, a portion of the back side of the workpiece that corresponds to a predetermined thickness is removed, thereby thinning the workpiece.

[0009] In this process, grinding generates chips that can adhere to the grinding surface of the grinding wheel and cause clogging. For smooth grinding of the workpiece, a moderate amount of abrasive grains must be exposed from the bond material on the underside (grinding surface) of the grinding wheel that comes into contact with the workpiece. However, if the chips get caught between the abrasive grains, the amount of exposed abrasive grains will be insufficient. Furthermore, repeated grinding of the workpiece can cause the abrasive grains exposed on the grinding surface of the grinding wheel to wear out (become dull).

[0010] In order to eliminate clogging and glazing and restore the grinding ability of the grinding wheel, grinding machines often perform a process of grinding the grinding surface (lower surface) of the grinding wheel at appropriate times to prepare it in a condition suitable for grinding. This process is called dressing (see, for example, Patent Document 1).

[0011] Grinding ability can also be restored by replacing the grinding wheel, but after replacement, there may be a discrepancy in the position (height) of the grinding surfaces of the multiple grinding stones attached to the underside of the wheel. In such cases, dressing is also effective in aligning the positions of the grinding surfaces between the grinding stones.

[0012] Dressing of a grinding wheel is performed, for example, by the following procedure. First, a dresser board is held below the grinding wheel attached to the spindle. The dresser board is, for example, a grinding wheel-like member provided with abrasive grains having a hardness sufficient to grind at least the bond material of the grinding wheel.

[0013] Next, while both the dresser board and the grinding wheel are rotated, the dresser board and the spindle are brought closer together in the vertical direction, so that the grinding surface of the grinding wheel comes into contact with the upper surface of the dresser board. As the grinding wheel and the dresser board slide against each other, the upper surface of the dresser board is ground by the abrasive grains exposed on the grinding surface of the grinding wheel, and the grinding surface of the grinding wheel is also ground by the abrasive grains exposed on the upper surface of the dresser board.

[0014] In the dressing process described above, it is desirable to appropriately control the relative movement between the dresser board and the grinding wheel in the vertical direction (the direction intersecting the sliding direction) and the load generated between them.

[0015] During dressing, the dresser board and the grinding wheel need to be pressed against each other with an appropriate amount of force. If this force is too weak or if the dresser board and the grinding wheel are not in contact, dressing will not be performed smoothly. Conversely, if the force is too strong, the amount of wear on the dresser board and the grinding wheel will be greater than necessary, resulting in premature wear.

[0016] Furthermore, when dressing begins, the dresser board and the grinding wheel must be brought close to each other, but if the relative movement speed between the dresser board and the grinding wheel is too slow, it may take a long time to start dressing, which may have a negative impact on productivity, whereas if the movement speed is too fast, there is a risk of the dresser board and the grinding wheel colliding with each other. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Patent Publication No. 2021-121464 Summary of the Invention [Problem to be solved by the invention]

[0018] An object of the present invention is to provide a dressing device, a dressing method, and a method for manufacturing chips that can suitably control the relative movement between a dresser board and a grinding wheel in a direction intersecting the sliding surface during dressing, or the load applied between them during dressing. [Means for solving the problem]

[0019] According to one aspect of the present invention, there is provided a dressing device that dresses a grinding wheel that grinds a workpiece by sliding the grinding wheel and a dresser board relative to each other, the dressing device having a board holding section that holds the dresser board, a moving section that moves the board holding section and the grinding wheel relative to each other in a direction that intersects with the sliding surface between the grinding wheel and the dresser board, and a measuring section that measures the load applied to the dresser board.

[0020] Preferably, in the dressing device, the moving unit is configured to move the board holding unit relative to the grinding wheel, and the dressing device further includes a measurement reference unit positioned on a trajectory of movement of the dresser board by the moving unit.

[0021] Preferably, the dressing device has an actuator in the moving section that moves the board holding section relative to the grinding wheel, and further has a guide section that limits the movement of the board holding section in a direction intersecting the movement direction of the board holding section by the actuator.

[0022] Preferably, the dressing device further comprises a workpiece holding section for holding the workpiece, and a grinding operation section to which a grinding wheel equipped with the grinding stone is rotatably mounted, and is configured to be able to grind the workpiece held in the workpiece holding section by rotating the grinding stone by operating the grinding wheel and bringing the grinding stone into contact with the workpiece, and is configured to be able to dress the grinding stone by rotating the grinding stone by operating the grinding wheel and bringing the grinding stone into contact with the dresser board held in the board holding section.

[0023] Preferably, the dressing device is configured to bring the dresser board into contact with the grinding wheel, which is rotating due to the operation of the grinding wheel, and to dress the grinding wheel, both in a state where the workpiece is not being ground by the grinding wheel and in a state where the workpiece held in the workpiece holding portion is being ground by the grinding wheel.

[0024] Preferably, the dressing device further includes a liquid supply nozzle for supplying liquid to the dresser board held by the board holding portion.

[0025] Preferably, the dressing device further includes a cleaning nozzle that supplies fluid to the grinding wheel, and the grinding wheel, the workpiece holding portion, and the board holding portion are arranged so that the trajectory of the grinding wheel, which rotates as the grinding wheel rotates, partially overlaps the workpiece held in the workpiece holding portion and partially overlaps the dresser board held in the board holding portion, when viewed from a direction perpendicular to the rotational plane of the grinding wheel, and the cleaning nozzle is arranged to supply fluid at a position on the trajectory of the grinding wheel that does not overlap either the workpiece held in the workpiece holding portion or the dresser board held in the board holding portion, when viewed from a direction perpendicular to the rotational plane of the grinding wheel.

[0026] According to another aspect of the present invention, there is provided a dressing method that includes a board holding section that holds a dresser board, and that performs a dressing step of dressing a grinding wheel using a dressing device that slides the dresser board held by the board holding section and a grinding wheel that grinds a workpiece relative to each other, wherein the dressing step includes a measuring step of measuring the load applied to the dresser board, and a load adjusting step of pressing the board holding section and the grinding wheel against each other in a direction that intersects with the sliding surfaces of the grinding wheel and the dresser board so that the value of the load measured in the measuring step falls within a predetermined numerical range.

[0027] Preferably, in the dressing method, the dressing device further includes a moving unit that moves the board holding unit relative to the grinding wheel in a direction that intersects with the sliding surface between the grinding wheel and the dresser board, and a measurement standard unit that is positioned on the trajectory of movement of the dresser board by the moving unit, and the dressing method performs a board thickness detection process in which the moving unit moves the board holding unit and records information regarding the position of the board holding unit at the time when the dresser board held by the board holding unit comes into contact with the measurement standard unit, and a distance adjustment process in which the amount of movement of the board holding unit by the moving unit is controlled based on the information regarding the position of the board holding unit recorded in the board thickness detection process.

[0028] Preferably, in the dressing method, the dressing device further includes a moving unit that moves the board holding unit relative to the grinding wheel in a direction that intersects with the sliding surface between the grinding wheel and the dresser board, and the board holding unit is moved by the moving unit, and a grinding wheel thickness detection process is carried out in which information regarding the position of the board holding unit at the time of contact between the board holding unit or the dresser board held by the board holding unit and the grinding wheel is recorded, and a distance adjustment process is carried out in which the amount of movement of the board holding unit by the moving unit is controlled based on the information regarding the position of the board holding unit recorded in the grinding wheel thickness detection process.

[0029] Preferably, the dressing step is performed by bringing the dresser board into contact with the grinding wheel while grinding the workpiece, or by bringing the dresser board into contact with the grinding wheel while not grinding the workpiece.

[0030] According to yet another aspect of the present invention, there is provided a method for producing chips by dividing a workpiece, the method comprising: a dressing step of dressing a grinding wheel using a dressing device having a board holding section for holding a dresser board and causing the dresser board held by the board holding section and a grinding wheel for grinding the workpiece to slide relative to each other; a grinding step of grinding the workpiece with the grinding wheel dressed in the dressing step, or dressing the grinding wheel in the dressing step and grinding the workpiece with the grinding wheel at the same time; and a dividing step of dividing the workpiece to form chips after the grinding step, wherein the dressing step includes a measuring step of measuring a load applied to the dresser board; and a load adjusting step of pressing the board holding section and the grinding wheel against each other in a direction intersecting the contact surface between the grinding wheel and the dresser board so that the value of the load measured in the measuring step falls within a predetermined numerical range.

[0031] Preferably, a workpiece having division starting points formed thereon is used as the workpiece, and in the dividing step, the workpiece is divided along the division starting points to form chips. [Effects of the Invention]

[0032] According to the dressing device, dressing method, and chip manufacturing method of each aspect of the present invention, by measuring the load applied to the dresser board, it is possible to suitably control the relative movement between the dresser board and the grinding wheel in a direction intersecting the sliding surface during dressing, or the load applied between them during dressing. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a perspective view schematically showing a part of the configuration of the dressing device. [Figure 2] FIG. 2 is a perspective view schematically showing the configuration of a dressing section of the dressing device of FIG. [Figure 3] FIG. 3 is a front view of the dressing portion of FIG. [Figure 4] 4 is a side cross-sectional view of the dress portion of FIG. 2, and corresponds to a view taken along the line IV-IV of FIG. [Figure 5] 5 is a front cross-sectional view showing the configuration of a moving part of the dressing part of FIG. 2. FIG. [Figure 6] FIG. 6 is a front view schematically showing the positional relationship between the grinding wheel handling section, the workpiece handling section, and the dressing section in the dressing device of FIG. [Figure 7] FIG. 7 is a plan view of FIG. [Figure 8] FIG. 8 is a flowchart showing an example of a procedure relating to the dressing method and the chip manufacturing method. [Figure 9] FIG. 9 is a side view schematically showing the positional relationship of each part in the board thickness detection process. [Figure 10] FIG. 10 is a side view schematically showing the positional relationship of each part in the grindstone thickness detection process. [Figure 11] FIG. 11 is a side view schematically showing the dividing step. DETAILED DESCRIPTION OF THE INVENTION

[0034] An embodiment of the present invention will be described with reference to the accompanying drawings. First, a dressing device used in this embodiment will be described. Note that, although the dressing device described here is a type in which a dressing function is incorporated into a grinding device (i.e., a dressing device that functions as both a dressing device and a grinding device), the dressing device may also be configured as a device separate and independent from the grinding device.

[0035] Fig. 1 is a perspective view showing a part of the configuration of the dressing device. Figs. 2 to 4 are a perspective view, a front view, and a side cross-sectional view showing the configuration of the dressing section of the dressing device shown in Fig. 1. For convenience of explanation, Fig. 4 omits the illustration of some parts such as the transmission section 36 and the guide section 42.

[0036] The dressing device 2 includes a grinding wheel handling section 4, a workpiece handling section 6, and a dressing section 8.

[0037] The grinding wheel handling unit 4 includes a spindle 10 as a grinding operation unit, and a moving unit 12 that moves the spindle 10 in the vertical direction.

[0038] 1, the spindle 10 is a generally cylindrical member extending along an axis in the vertical direction (Z direction), and has a grinding wheel 14 attached to its lower end. The grinding wheel 14 is attached to the spindle 10 so that the axis of the generally cylindrical spindle 10 coincides with its rotation axis, and is rotated along a horizontal plane (XY plane) around the rotation axis by the operation of a motor or the like (not shown) provided on the spindle 10.

[0039] In this specification, expressions such as "along the vertical direction (Z direction)" or "along the horizontal plane" may be used, but these do not only mean that the orientation of an object or its axis, etc., strictly coincides with the vertical direction (Z direction) or the horizontal plane, etc., but also include cases where the object is slightly inclined or curved relative to the vertical or horizontal direction.

[0040] The grinding wheel 14 is a disk-shaped component to which multiple grinding stones 16 are attached. The multiple grinding stones 16 are arranged in an annular shape on one side of the grinding wheel 14, and the grinding wheel 14 is attached to the lower end of the spindle 10 with the side on which the grinding stones 16 are attached facing downward.

[0041] The moving unit 12 is a mechanism that relatively moves the grinding wheel 16 and the workpiece 18 that is the object to be ground, in a direction (along the Z direction) that intersects with the sliding surface between the grinding wheel 16 and the workpiece 18 when grinding the workpiece 18. The moving unit 12 also functions as a mechanism that relatively moves the grinding wheel 16 and a dresser board 24 that dresses the grinding wheel 16, in a direction (along the Z direction) that intersects with the sliding surface between the grinding wheel 16 and the dresser board 24 when dressing the grinding wheel 16.

[0042] The moving part 12 provided in the grinding wheel handling part 4 is capable of moving the spindle 10 up and down by, for example, a ball screw arranged along the vertical direction and a mechanism (not shown) with a pulse motor that rotates the ball screw. However, the mechanism by which the moving part 12 moves the grinding operation part (spindle) 10 is not limited to this, and various mechanisms can be adopted as the moving part 12.

[0043] In addition, the moving unit, which is a mechanism for moving the grinding wheel 16 and the workpiece 18 relative to each other along the Z direction, may be equipped with a mechanism for moving the workpiece 18 instead of or in addition to the mechanism (moving unit 12) for moving the grinding wheel 16 side (spindle 10) as described above.

[0044] In this embodiment, in addition to the above-described moving unit 12 that moves the grinding wheel 16 (spindle 10), the dressing unit 8 is provided with a mechanism (moving unit 30) that moves the dresser board 24 side as a moving unit that moves the grinding wheel 16 and the dresser board 24 relatively in the Z direction. The configuration and function of the moving unit 30 will be described in detail later.

[0045] As shown in FIG. 1, the workpiece handling section 6 includes a chuck table 20 serving as a workpiece holding section for holding the workpiece 18, and a support base 22 for supporting the chuck table 20.

[0046] The workpiece 18 is, for example, a disk-shaped wafer made of a semiconductor material such as silicon, but there are no limitations on the material, shape, structure, size, type, or use of the workpiece 18. For example, the workpiece 18 may be a wafer made of a semiconductor other than silicon (GaAs, InP, GaN, SiC, etc.), glass, ceramics, resin, metal, etc. Furthermore, the workpiece 18 may be an article other than a wafer. Various articles that can be ground by the grinding wheel 16 can be considered as the workpiece 18.

[0047] The chuck table 20, which serves as a workpiece holder, has an upper surface as a holding surface 20a, and holds the disk-shaped workpiece 18 by suctioning the underside of the workpiece 18 onto the holding surface 20a. The chuck table 20 has a built-in mechanism (not shown) that generates negative pressure between the chuck table 20 and the article on the holding surface 20a, thereby suctioning the workpiece 18 to the holding surface 20a.

[0048] The support table 22 in this embodiment is a rotary table having a chuck table 20 on its upper surface. The support table 22, which is a rotary table, is configured to rotate around a rotation axis that is aligned in the vertical direction (Z direction). The support table 22 may also be configured to move up and down along the Z direction.

[0049] The installation position of the chuck table 20 on the support base 22 is offset from the position of the rotation axis of the support base 22 when viewed from the Z direction. In other words, the position of the chuck table 20 varies with the rotation of the support base 22, and this makes it possible to move the position of the chuck table 20 in the horizontal plane (XY plane) relative to the spindle 10 and grinding wheel 14 provided in the grinding wheel handling unit 4.

[0050] The chuck table 20 is supported by a support base 22 so as to be rotatable about a rotation axis extending in the vertical direction (Z direction).

[0051] As shown in Figures 1 to 4, the dressing section 8 includes a chuck table 26 as a board holding section that holds the dresser board 24, a support base 28 that supports the chuck table 26, a moving section 30 that moves the chuck table 26 and the support base 28 in the vertical direction (Z direction) relative to the grinding wheel 14 and the grinding stone 16, and an auxiliary support section 38 that supports the support base 28.

[0052] The support base 28 is a base that is supported by the auxiliary support unit 38 and is movable up and down in the vertical direction (Z direction) by the moving unit 30, and in the example shown here is a plate-like member that forms a surface along a horizontal plane (XY plane). The configurations of the auxiliary support unit 38 and the moving unit 30 will be described in detail later.

[0053] The main body of the chuck table 26, which serves as a board holding section, protrudes above the support base 28, and its upper surface forms the holding surface 26a. A sealing unit 32 is provided on the opposite side (lower side) of the surface of the plate-shaped support base 28 from the chuck table 26. The sealing unit 32 is a structure for connecting the chuck table 26 to a negative pressure source (not shown) that generates negative pressure on the article on the holding surface 26a of the chuck table 26.

[0054] The sealing unit 32 is divided into a lower structure (non-rotating portion) and an upper structure (rotating portion) that is rotatable about an axis that is perpendicular to the lower structure. A chuck table 26 is attached to the upper part of the rotating portion, and rotation of the rotating portion causes the chuck table 26 to rotate relative to the support base 28.

[0055] Inside the seal unit 32, a flow path that communicates with the inside of the chuck table 26 is provided across the rotating and non-rotating parts, and at the connection part between the rotating and non-rotating parts in the flow path, a connection structure using a magnetic fluid, an O-ring, etc., allows rotation between the rotating and non-rotating parts while maintaining the airtightness of the flow path.

[0056] The non-rotating portion constituting the lower side of the seal unit 32 is connected to an external negative pressure source (not shown) via a pipe, which is further connected to a positive pressure source (not shown) via a valve.

[0057] The negative pressure source is, for example, an ejector, and the positive pressure source is, for example, a mechanism for supplying compressed air. The valve is configured to switch the object to which the piping attached to the seal unit 32 communicates between the negative pressure source and the positive pressure source.

[0058] When the sealing unit 32 is connected to the negative pressure source by switching the valve, negative pressure is applied to the chuck table 26, and the dresser board 24 is adsorbed to the holding surface 26a. On the other hand, when the sealing unit 32 is connected to the positive pressure source, air is blown from the holding surface 26a of the chuck table 26, which allows the dresser board 24 to be easily removed from the chuck table 26.

[0059] The main body of the chuck table 26 (the portion that protrudes above the support base 28 and holds the dresser board 24 on its upper surface (holding surface 26a)) is configured to rotate about a rotation axis that is aligned in the vertical direction (Z direction) relative to the support base 28. A servo motor 34 is attached to the underside of the support base 28 as a rotation drive unit for driving the rotation of the main body of the chuck table 26.

[0060] The servo motor 34 and the chuck table 26 are connected by an endless belt 36, which serves as a transmission unit for transmitting rotation, below the support base 28. When the servo motor 34 is driven, its rotational force is transmitted to the chuck table 26 via the belt 36, and the chuck table 26 rotates together with the dresser board 24 held on the holding surface 26a.

[0061] A base 40 that forms the bottom of the dressing section 8 is located below the support stand 28. The base 40 is a plate-like member that is placed on the floor or the like of the internal space of the dressing device 2 and forms the base of the dressing section 8.

[0062] A moving unit 30 and an auxiliary support unit 38 are attached along the vertical direction (Z direction) between a plate-shaped support base 28 and a base base 40, which are arranged one above the other to form a surface along a horizontal plane (XY plane), and these devices interconnect the support base 28 and the base base 40.

[0063] The auxiliary support part 38 is, for example, a fluid pressure cylinder such as an air cylinder, which expands and contracts due to the pressure of the fluid contained inside, and is capable of applying a load along the expansion and contraction direction to an object connected to both ends in the expansion and contraction direction.

[0064] The auxiliary support part 38, which is a fluid pressure cylinder, is attached between the support stand 28 and the base stand 40 in a position where the extension direction is along the vertical direction (Z direction). The same applies to the moving part 30.

[0065] In this embodiment, the fluid pressure cylinder (auxiliary support part) 38 freely expands and contracts in accordance with the expansion and contraction of the moving part 30, and is controlled so as to apply a load equivalent to the weight of the support base 28 and the various devices and parts supported by the support base 28 (the chuck table 26, the seal unit 32, the servo motor 34, the belt 36, and the sheath part 42a of the guide part 42 described below, the guide pin 30g and pressing body 30h that constitute the moving part 30, the load sensor 30b, etc.) upward to the support base 28.

[0066] For ease of explanation, the "weight of the support base 28 and the various devices and parts supported by the support base 28" will be referred to simply as the "weight of the support base 28."

[0067] Here, the load required to support the support table 28 ("the weight of the support table 28") varies depending on, for example, the weight of the dresser board 24 held on the chuck table 26, the inclination of the support table 28, etc., but the load applied upward from the fluid pressure cylinder 38 to the support table 28 does not need to strictly match the weight of the support table 28. It is sufficient if the fluid pressure cylinder 38 can support most of the weight of the support table 28.

[0068] Furthermore, below the support base 28, a guide unit 42 is provided to maintain the posture of the chuck table 26 and the support base 28 as the support base 28 moves up and down and is supported by the moving unit 30 and the auxiliary support unit 38. The dressing unit 8 of this embodiment is provided with a total of two guide units 42, sandwiching the auxiliary support unit 38 in a plan view.

[0069] Each guide portion 42 is configured with a sheath portion 42a and a pillar portion 42b. The sheath portion 42a is a cylindrical member extending downward from the underside of the support base 28, with its bottom end surface open. The pillar portion 42b is a rod-shaped member extending upward from the base 40 below the support base 28, with its upper portion inserted into the sheath portion 42a. The cross-sectional shape and dimensions of the sheath portion 42a along the XY plane and the cross-sectional shape and dimensions of the pillar portion 42b along the XY plane are approximately the same, so that the sheath portion 42a and the pillar portion 42b slide relative to each other in the Z direction but barely move relative to each other in the XY directions.

[0070] In this way, the sheath portion 42a, which is a member fixed to the support base 28 side, and the pillar portion 42b, which is a member fixed to the base 40 side, restrict each other's movement, so that the guide portion 42 restricts the movement of the chuck table 26 in a direction (direction along the XY plane) that intersects the direction of movement of the chuck table 26 by the moving portion 30 (direction along the Z direction).

[0071] In the dressing unit 8 having the above-described mechanism, the weight of the support base 28 is supported mainly by the fluid pressure cylinder 38. The point of application of the load applied to the support base 28 by the fluid pressure cylinder 38 does not necessarily coincide with the center of gravity of the support base 28's own weight, but even if the support base 28 attempts to tilt due to a moment generated by eccentricity, movement of the support base 28 in a direction intersecting the Z direction is restricted by the guide unit 42, and this function keeps the support base 28 in a position along the horizontal plane (XY plane).

[0072] Furthermore, since the fluid pressure cylinder 38 expands and contracts in response to the expansion and contraction of the moving part 30, the fluid pressure cylinder 38 applies approximately the same load to the support base 28 at any height, regardless of the expansion or contraction state of the moving part 30. Furthermore, when the moving part 30 and the fluid pressure cylinder 38 expand and contract, fluctuations in the load applied by these may generate a moment that tends to tilt the support base 28, but even in that case, the guide part 42 works to maintain the same posture of the support base 28.

[0073] The specific configuration of the auxiliary support unit may be any configuration that allows movement of the support base 28 in the vertical direction (Z direction) and that can urge the support base 28 with an appropriate force in a direction away from the base 40 in the vertical direction (Z direction). For example, instead of a fluid pressure cylinder, a mechanism using a helical spring or the like can also be used as the auxiliary support unit. However, a fluid pressure cylinder is particularly suitable as the auxiliary support unit because it allows for free adjustment of the load along with the length.

[0074] Furthermore, the configuration of the guide unit 42 is not limited to the example shown here. For example, a mechanism may be used in which holes are provided that penetrate the support table 28 from top to bottom, and columnar members extending in the vertical direction are fixed to the base 40 and passed through the holes, or a mechanism may be used in which the entire support table 28 in a plan view is surrounded by a wall or fence-like structure. A mechanism that limits the tilt or movement of the support table 28 by magnetic force or the resilience of a spring or the like is also theoretically conceivable.

[0075] The mechanism of the moving unit 30 will now be described. Fig. 5 is a front cross-sectional view showing the configuration of the main parts of the moving unit 30. The moving unit 30 is equipped with an actuator 30a that extends and retracts up and down along the vertical direction (Z direction) and moves the chuck table 26 and the support base 28 relative to the grinding wheel 16 (see Fig. 1), and a load sensor 30b as a measuring unit that detects the load applied to the dresser board 24 held by the chuck table 26.

[0076] The actuator 30a is a mechanism that expands and contracts in the vertical direction (Z direction; a direction that intersects with the sliding surface between the grinding wheel 16 and the dresser board 24 during dressing) and generates a biasing force along the expansion and contraction direction. Various mechanisms for generating force are possible, such as an electromagnetic type, a fluid pressure type, or a rack-and-pinion type mechanism.

[0077] The load sensor 30b is, for example, a load cell, and is attached to the underside of the support base 28. When another object (here, a pressing body 30h, which will be described later) comes into contact with this load sensor 30b from below, the load applied by the object is detected and input to the controller 50, which will be described later.

[0078] That is, the load sensor 30b is a sensor provided to detect the load applied to the dresser board 24 held on the chuck table 26, but in this embodiment, the load is detected as a load applied from the actuator 30a to the support base 28.

[0079] The actuator 30a comprises a cylindrical main body 30c and a rod 30d partially inserted into the main body 30c. The rod 30d moves in and out of the main body 30c from one end along the central axis by electromagnetic force, fluid pressure, etc., which allows the actuator 30a as a whole to expand and contract in the longitudinal direction.

[0080] The actuator 30a is attached to the base 40 on the side of the main body 30c where the rod 30d does not move in and out, and is attached between the support base 28 and the base 40 with the tip 30e of the rod 30d facing the upper support base 28. The load sensor 30b is located on the extension line of the rod 30d.

[0081] Here, as the actuator 30a extends, the tip 30e of the rod 30d may come into direct contact with the load sensor 30b, but in this embodiment, a buffer section 30f is provided between the rod 30d and the load sensor 30b, so that the rod 30d and the load sensor 30b do not come into direct contact with each other.

[0082] The configuration of this buffer section 30f will be described below. The buffer section 30f includes a guide pin 30g, a pressing body 30h, and a biasing body 30j.

[0083] A plurality of guide pins 30g are provided around the load sensor 30b provided on the underside of the support base 28 so as to protrude downward from the underside of the support base 28. A pressing body 30h is supported by the plurality of guide pins 30g.

[0084] The pressing body 30h is a plate-like member that is supported below the load sensor 30b and above the tip 30e of the rod 30d in a position that forms a surface along the horizontal plane (XY plane). An upward protrusion is formed in the center of the top surface of the pressing body 30h, and this protrusion comes into contact with the load sensor 30b as the actuator 30a extends, as described below.

[0085] Holes that penetrate the plate-shaped pressing body 30h from top to bottom are provided on the periphery of the pressing body 30h at positions that correspond to the arrangement of the multiple guide pins 30g on the underside of the support base 28, and the pressing body 30h is installed by passing each guide pin 30g through each of the holes. The lower ends of the guide pins 30g that protrude downward from the support base 28 are provided with heads that have a larger diameter than the rest of the body, and when the pressing body 30h is not pushed up from below by the rod 30d of the actuator 30a (the state shown by the solid line in FIG. 5), the pressing body 30h is suspended from the guide pins 30g at the positions of the heads provided on the multiple guide pins 30g.

[0086] A separator 30i is provided on the lower surface of the pressing body 30h so as to protrude downward from the lower surface. The separator 30i is a cylindrical member provided so as to surround the tip 30e of the rod 30d in a plan view (view from the Z direction), and the tip 30e is inserted into the separator 30i from below.

[0087] Furthermore, a biasing member 30j is provided between the separating portion 30i and the rod 30d, and biases the pressing member 30h and the rod 30d in a direction that separates them from each other along the extension / contraction direction of the actuator 30a.

[0088] In this embodiment, biasing body 30j is a helical spring (although, of course, other mechanisms may be used as the biasing body depending on the configuration of the actuator, etc.). In actuator 30a of this embodiment, the diameter of tip portion 30e of rod 30d is set smaller than the diameter of other portions (hereinafter referred to as "thin diameter portion" for convenience), and biasing body 30j, which is a helical spring, is disposed so as to surround tip portion 30e configured as this thin diameter portion.

[0089] A part of the tip 30e, which is the thin diameter portion, is located within the separated portion 30i, and the upper end of the biasing body 30j surrounding the thin diameter portion (tip) 30e contacts the lower end of the separated portion 30i, while the lower end of the biasing body 30j contacts the step surface between the tip 30e of the rod 30d, which is configured as the thin diameter portion, and the other portion with a larger diameter.

[0090] In this embodiment, the buffer section 30f configured in this manner is interposed between the rod 30d and the load sensor 30b, and when the actuator 30a attempts to push up the support base 28, the force is applied via the biasing member 30j and the pressing member 30h.

[0091] Here, the dressing part 8 of this embodiment is provided with an auxiliary support part (fluid pressure cylinder) 38 as a mechanism for supporting the support base 28 on the base 40, and the weight of the support base 28 is mainly supported by the auxiliary support part, the fluid pressure cylinder 38. As a result, when the actuator 30a of the moving part 30 is in a contracted state, the tip of the rod 30d is positioned sufficiently below the underside of the support base 28 and the load sensor 30b attached thereto.

[0092] In this state, the pressing body 30h constituting the buffer portion 30f is supported in a manner that it is suspended from the lower surface of the support base 28 by a guide pin 30g, as shown by the solid line in FIG.

[0093] As the actuator 30a is extended from here, the rod 30d extends upward, and as shown by the dashed line in Figure 5, with the pressing body 30h placed on the tip 30e of the rod 30d via the biasing body 30j, the pressing body 30h rises along the longitudinal direction of the guide pin 30g, and the central protrusion of the pressing body 30h comes into contact with the load sensor 30b.

[0094] When the actuator 30a is further extended, a force is applied from the rod 30d via the biasing member 30j and the pressing member h to the load sensor 30b and the support base 28 in a manner that pushes them up from below. At this time, the load sensor 30b detects the load applied from the rod 30d.

[0095] Furthermore, the dressing unit 8 is equipped with a measurement reference unit 44 for detecting the position of the board holding unit (chuck table) 26 in the vertical direction (Z direction) by the moving unit 30. The measurement reference unit 44 in this embodiment is a rod-shaped member whose base is attached to the base 40, extends upward from the base 40 around the support base 28, bends at a height above the holding surface 26a of the chuck table 26, and extends above the holding surface 26a.

[0096] The tip of the measurement reference portion 44 is located above the chuck table 26, that is, on the trajectory of movement of the dresser board 24 held on the holding surface 26a of the chuck table 26 when the dresser board 24 is held on the holding surface 26a of the chuck table 26 and the chuck table 26 is moved in the vertical direction (Z direction). This position is also on the trajectory of movement of the holding surface 26a of the chuck table 26 itself along the Z direction.

[0097] Since the tip of the measurement reference portion 44 is located in this position, when the support base 28 and the chuck table 26 are raised by the moving portion 30, the holding surface 26a of the chuck table 26, or the dresser board 24 held on the holding surface 26a, comes into contact with the tip of the measurement reference portion 44 at a specific position.

[0098] Furthermore, the measurement reference part 44 is arranged in a position where the part located above the chuck table 26 does not overlap with the grinding wheel 14 or the grinding stone 16 in a plan view (view from the Z direction) so as not to interfere with the dressing operation described below. Alternatively, the measurement reference part 44 may be configured so that it can be moved or removed, for example, to move away from the trajectory of the chuck table 26 or the dresser board 24 as needed.

[0099] The measurement reference unit is not limited to the examples given here, and various configurations are possible. The measurement reference unit may have any configuration as long as at least a portion thereof is located on the trajectory of the dresser board 24 that accompanies the movement of the holding surface 26a of the chuck table 26 in the vertical direction (Z direction), and its position in the vertical direction (Z direction) can be fixed relative to the base 40 (the main body 30c that does not move together with the rod 30d as the actuator 30a expands and contracts, the housing of the dressing device 2 on which the dressing unit 8 is installed, etc.).

[0100] The dressing unit 8 also includes a liquid supply nozzle 46 that supplies a liquid such as water to the grinding wheel 16 and the dresser board 24, which slide against each other, during dressing. In the example shown in Figures 3 and 4, the discharge port of the liquid supply nozzle 46 is located above the chuck table 26, which is the board holding unit, and the liquid required for dressing (dressing liquid) is supplied from here during dressing.

[0101] For convenience of drawing, the measurement reference portion 44 and the liquid supply nozzle 46 are omitted from FIGS.

[0102] 6 and 7 show examples of the arrangement of a nozzle (cleaning nozzle 48) having a function similar to that of the liquid supply nozzle 46. Figures 6 and 7 show a schematic diagram of the positional relationship between the grinding wheel handling unit 4, the workpiece handling unit 6, and the dressing unit 8 in the dressing device of Figure 1, with Figure 6 being a front view and Figure 7 being a plan view.

[0103] In the dressing device 2 of this embodiment, the grinding wheel handling unit 4, the dressing unit 8, and the chuck table 20 of the workpiece handling unit 6 can be positioned as shown in Figures 6 and 7 by rotating the support base 22 of the workpiece handling unit 6. In the positional relationship shown here, by rotating the support base 22 of the workpiece handling unit 6, the chuck table 20 serving as a workpiece holding unit attached to the support base 22 and the chuck table 26 serving as a board holding unit attached to the support base 28 of the adjacent dressing unit 8 are brought into close proximity.

[0104] When the chuck tables 20 and 26 are close to each other in this manner, as shown in Figure 7, the grinding wheel 14 can be positioned so that, in a plan view (view from the Z direction), part of the rotation range of the grinding wheel 16 attached to the grinding wheel 14 of the grinding wheel handling unit 4 overlaps with the chuck table 20 as the workpiece holding unit, and another part overlaps with the chuck table 26 as the board holding unit.

[0105] In other words, the grinding wheel 14, the workpiece holding portion 20 and the board holding portion 26 are positioned so that the trajectory of the grinding wheel 16, which rotates as the grinding wheel 14 rotates, partially overlaps with the workpiece 18 held in the workpiece holding portion 20 and partially overlaps with the dresser board 24 held in the board holding portion 26 when viewed from a direction perpendicular to the rotation plane of the grinding wheel 16 (a direction along the Z direction).

[0106] In this positional relationship, some of the multiple grinding stones 16 provided on the grinding wheel 14 are in contact with the workpiece 18 on the chuck table 20, and another part is in contact with the dresser board 24 on the chuck table 26. By rotating the grinding wheel 14 in this state, it is possible to simultaneously grind the workpiece 18 and dress the grinding stones 16. At this time, the chuck tables 20 and 26 are also rotated about an axis along the Z direction together with the workpiece 18 and the dresser board 24 held on the holding surfaces 20a and 26a, respectively.

[0107] Assuming that grinding and dressing are performed simultaneously using this positional relationship, in the example shown in Figures 6 and 7, the cleaning nozzle 48 that supplies fluid to the grinding wheel 16 is positioned so that it supplies fluid to a position on the trajectory of the grinding wheel 16 that does not overlap with either the workpiece 18 held on the chuck table 20 as a workpiece holder or the dresser board 24 held on the chuck table 26 as a board holder, when viewed from a direction perpendicular to the rotation plane of the grinding wheel 16 (direction along the Z direction).

[0108] That is, the cleaning nozzle 48 has a discharge port at this position, from which a fluid such as water or air is sprayed onto the grinding wheel 16. When a fluid is supplied to the rotating grinding wheel 16 at this position, the grinding wheel 16 can be cleaned with the fluid at a position where the grinding wheel 16 does not overlap either the workpiece 18 or the dresser board 24.

[0109] It is also possible to retract the chuck table 20 and rotate the grinding wheel 14 so that the grinding stone 16 attached to the grinding wheel 14 is in contact only with the dresser board 24 on the chuck table 26, thereby dressing the grinding stone 16 only without grinding the workpiece 18.

[0110] In other words, in the dressing device 2 of this embodiment, by adjusting the relative positions of the grinding wheel handling section 4, the workpiece handling section 6 and the dressing section 8, it is possible to bring the dresser board 24 into contact with the grinding wheel 16, which is rotating due to the operation of the grinding wheel 14, and to dress the grinding wheel 16, both in a state where the workpiece 18 is not being ground by the grinding wheel 16 and in a state where the workpiece 18 held in the workpiece holding section 20 is being ground by the grinding wheel 16.

[0111] A controller 50 that controls the operation of each component of the dressing device 2 is connected to the dressing device 2 (see FIG. 1). The controller 50 is configured, for example, by a computer, and includes a calculation unit 50a that performs various calculations necessary for the operation of the dressing device 2, and a storage unit 50b that stores various information (data, programs, etc.) used for the operation of the dressing device 2. The calculation unit 50a includes a processor such as a CPU (Central Processing Unit). The storage unit 50b includes memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0112] In addition, the controller 50 includes a communication unit 50c that communicates with each unit of the dressing device 2 and inputs control signals thereto. The communication unit 50c inputs various control signals to the grinding wheel handling unit 4, the workpiece handling unit 6, and the dressing unit 8 through wired or wireless communication.

[0113] The controller 50 controls, for example, the following operations based on a program: Of course, the controller 50 may also control operations other than those listed here.

[0114] (Grinding wheel handling section 4) Rotation of the grinding wheel 14 Movement of the spindle 10, the grinding wheel 14 and the grinding stone 16 along the Z direction by the moving part 12

[0115] (Workpiece handling department 6) Rotation of the support base 22 Chuck table 20 rotation - Adsorption of the workpiece 18 on the chuck table 20

[0116] (Dress Section 8) Adjustment of the extension and contraction of the actuator 30a in the moving part 30 and the load Adjustment of extension and contraction of the fluid pressure cylinder 38 and load Rotation of the chuck table 26 (operation of the servo motor 34 which is the rotation drive unit) The dresser board 24 is attracted to the chuck table 26 ( Supply of liquid from the liquid supply nozzle 46 Fluid supply from the cleaning nozzle 48 An input / output unit 50d is connected to the controller 50. The input / output unit 50d is a user interface such as a keyboard or a monitor display, and an operator operating the dressing device 2 can operate each part of the dressing device 2 via the controller 50 by inputting operations to the input / output unit 50d.

[0117] The dressing and grinding procedures performed by the dressing unit 8 and the dressing device 2 equipped with the dressing unit 8 will be described with reference to Figures 8 to 10 as appropriate. Figure 8 is a flowchart showing an example of the procedure for the dressing method. Figures 9 and 10 are side views schematically showing the positional relationships of the various parts in the board thickness detection step and the grindstone thickness detection step, respectively, in the procedure of Figure 8.

[0118] Dressing of the grinding wheel 16 is performed by bringing the grinding wheel 16 and the dresser board 24 into contact with each other and sliding them relative to each other. When performing this dressing operation in the dressing device 2 and dressing section 8 described above, it is first necessary to adjust the distance between the grinding wheel 16 and the dresser board 24 and bring them into contact with each other. This process is the distance adjustment process (step S20), and furthermore, in the procedure shown in FIG. 8, a board thickness detection process (step S10) is performed as a process for acquiring information used in the distance adjustment process.

[0119] In step S10 (board thickness detection process), the actuator 30a of the moving unit 30 moves the chuck table 26, which is the board holding unit of the dressing unit 8, along the Z direction, and information regarding the position of the board holding unit (chuck table) 26 at the time when the dresser board 24 held on the chuck table 26 comes into contact with the tip of the measurement reference unit 44 is recorded.

[0120] 9, the actuator 30a (see FIG. 5) of the moving unit 30 is first contracted, and the chuck table 26 is retracted downward, and the dresser board 24 is held on the holding surface 26a of the chuck table 26. With the dresser board 24 placed on the holding surface 26a, a negative pressure is applied to the inside of the chuck table 26 from a negative pressure source (not shown) connected to the sealing unit 32 (see FIG. 3), and the dresser board 24 is adsorbed to the holding surface 26a.

[0121] Next, the actuator 30a is extended, and the chuck table 26 rises as shown by the arrow in Fig. 9. At this time, the tip of the measurement reference part 44 is positioned above the chuck table 26, while the grinding wheel 14 is retracted upward by the operation of the moving part 12 so that the cutting edge (lower end) of the grinding stone 16 is positioned above the underside of the tip of the measurement reference part 44.

[0122] When the actuator 30a extends, as shown by the broken line in FIG. 9, the dresser board 24 held on the holding surface 26a of the chuck table 26 comes into contact with the measurement reference portion 44. The fact that the dresser board 24 has come into contact with the measurement reference portion 44 is detected by the load sensor 30b (see FIG. 5) or a change in the detected value of the load.

[0123] As described above, the weight of the support base 28 is almost entirely supported by the auxiliary support portion 38, and the auxiliary support portion 38 expands and contracts in response to the expansion and contraction of the moving portion 30 due to the operation of the actuator 30a. Therefore, until the dresser board 24 comes into contact with the measurement reference portion 44, the load detected by the load sensor 30b is zero or a very small value.

[0124] When the dresser board 24 comes into contact with the measurement reference portion 44, the measurement reference portion 44 prevents the support base 28 from rising. When the actuator 30a extends further from this state, the pressing body 30h, which has been suspended by the guide pin 30g on the underside of the support base 28, is pushed up by the tip portion 30e of the rod 30d and rises, coming into contact with the load sensor 30b (see FIG. 5).

[0125] The detected value of the load by the load sensor 30b changes due to contact of the pressing body 30h. Since the detected value from the load sensor 30b is input to the controller 50 (see FIG. 1), the controller 50 can recognize the contact of the pressing body 30h with the load sensor 30b as a change in the detected value of the load by the load sensor 30b.

[0126] At this point, the controller 50 records information relating to the position of the chuck table 26. "Information relating to the position of the chuck table 26" refers to information itself indicating the position of the chuck table 26 in the Z direction, or related information from which the position of the chuck table 26 in the Z direction can be determined.

[0127] That is, the "information relating to the position of the chuck table 26" may be, for example, a numerical value representing the position of the chuck table 26 in the Z direction or the position of the support base 28 to which it is attached (the position relative to the base 40 or the floor of the dressing device 2, etc.), or it may be the extension amount of the actuator 30a or the fluid pressure cylinder 38 at that time, or the control amount therefor, etc. Alternatively, the thickness of the dresser board 24 calculated using the procedure described below may also fall under the "information relating to the position of the chuck table 26 at the time when the dresser board 24 held by the chuck table 26 comes into contact with the tip of the measurement reference portion 44."

[0128] Before or after the above-described operation of raising the support base 28 with the dresser board 24 held on the chuck table 26 and bringing the dresser board 24 into contact with the measurement reference portion 44, the support base 28 is raised without the dresser board 24 held on the chuck table 26, bringing the holding surface 26a into contact with the measurement reference portion 44, and the positions of the support base 28 or chuck table 26 in the Z direction at that time, or the extension amounts of the actuator 30a and the fluid pressure cylinder 38, etc., are recorded. By comparing this data with the "information regarding the position of the chuck table 26 at the time when the dresser board 24 held on the chuck table 26 came into contact with the tip of the measurement reference portion 44" recorded in the previous operation, the thickness of the dresser board 24 can be determined.

[0129] Specifically, for example, if the difference in the position of the chuck table 26 in the Z direction at both points in time is calculated, this directly corresponds to the thickness of the dresser board 24.

[0130] Here, in this embodiment, a fluid pressure cylinder 38 is provided as an auxiliary support unit separate from the moving unit 30 as a mechanism for supporting the support base 28, so that almost no load is generated between the moving unit 30 and the support base 28 until the chuck table 26 or the item (dresser board 24) held on the chuck table 26 comes into contact with another object above, etc.

[0131] In this way, during the board thickness detection process (step S10) described above and the grinding wheel thickness detection process (step S70) described later, the timing when the dresser board 24 or the chuck table 26 comes into contact with the measurement reference portion 44 or the grinding wheel 16 can be grasped as the point in time when the load detection value of the load sensor 30b changes significantly to the positive side from a state of zero or close to zero, thereby enabling accurate detection of such contacts.

[0132] Furthermore, for most of the time during the board thickness detection process (step S10), grinding wheel thickness detection process (step S70), and movement adjustment process (step S20), almost no load is applied to the moving unit 30. Furthermore, during the dressing process (step S30), the moving unit 30 does not need to support the weight of the support table 28, and the actuator 30a only needs to generate the load necessary to press the dresser board 24 against the grinding wheel 16, so a small, low-output device is sufficient as a power source such as a motor provided in the actuator 30a.

[0133] However, contact detection based on the same principle as the mechanism described above is possible without providing the auxiliary support part 38. In this case, for example, the entire weight of the support base 28 is borne by the moving part 30. In the actuator 30a that constitutes the moving part 30, the tip end 30e of the rod 30d is in direct contact with the load sensor 30b at all times.

[0134] When such a configuration is adopted, the load sensor 30b detects a load corresponding to the weight of the support base 28 at the start of the grindstone thickness detection process (step S30), but the value of the load increases when the dresser board 24 comes into contact with the measurement reference portion 44. This makes it possible to detect the contact.

[0135] Next, a distance adjustment process (step S20) is performed to control the amount of movement of the chuck table 26 by the moving unit 30 based on information regarding the position of the board holding unit (chuck table) 26 recorded in the board thickness detection process (step S10).

[0136] When dressing, the cutting edge (lower end) of the grinding stone 16 attached to the grinding wheel 14 is brought into contact with the upper surface of the dresser board 24 held by the chuck table 26, but to prevent the two from colliding or excessive force being applied between them, it is necessary to avoid the two from approaching each other at too high a speed when they come into contact. On the other hand, moving the two at a low speed from positions too far apart takes time, which may affect production efficiency.

[0137] Therefore, when bringing the grinding wheel 16 and the dresser board 24 closer to each other, it is effective to move them at a high speed until they are as close as possible, and then slow down the speed of their movement once they are sufficiently close.

[0138] A slow movement performed for this purpose is sometimes called an air cut. Therefore, in the following, when two objects (here, for example, the grinding wheel 16 and the dresser board 24 are assumed) are brought close to each other and brought into contact, the relatively slow movement performed just before contact will be referred to as an air cut, and the relatively fast movement performed before the air cut will be referred to as a forward movement, for the sake of convenience.

[0139] The timing for switching from forward movement to air cut, or the distance between the two at that time, can be determined based on measurement errors, the accuracy of the operation of each part, etc., as "the timing or distance that allows the two to get as close as possible without causing an unexpected collision between the two."

[0140] For this purpose, it is effective to use information about the thickness of the dresser board 24 held by the chuck table 26. If the position of the cutting edge (lower end) of the grinding wheel 16 in the Z direction can be determined and, in addition, the thickness of the dresser board 24 (i.e., the distance between the holding surface 26a of the chuck table 26 and the upper surface of the dresser board 24) can be determined, it can be determined how far the chuck table 26 needs to be moved before the two come into contact.

[0141] In a mechanism such as that of this embodiment in which the dresser board 24 is held on the chuck table 26 and moved along the Z direction, the "information about the thickness of the dresser board 24" is equivalent to the "information about the position of the chuck table 26" recorded in the previous step S10. Therefore, in the distance adjustment process of step S20, the information recorded in step S10 is used to control the movement of the chuck table 26 by the moving unit 30.

[0142] For example, as shown in Figure 10, first, the moving part 12 (see Figure 1) of the grinding wheel handling part 4 moves the position of the grinding wheel 14 in the Z direction to a position where the grinding wheel 16 can be dressed (lowered toward the chuck table 26 of the dressing part 8 located below).

[0143] Next, the actuator 30a (see FIG. 5) provided on the moving part 30 of the dressing part 8 is extended, causing the chuck table 26 to rise as shown by the arrow in FIG. 10, and the dresser board 24 is brought closer to and into contact with the grinding wheel 16. During this movement of the chuck table 26, the timing for switching between forward movement and air cutting is adjusted based on the information recorded in step S10.

[0144] The dressing process (step S30) begins when the dresser board 24 and the chuck table 26 come into contact with each other, as indicated by the dashed line in Fig. 10. A load is applied from below to the support base 28 by the actuator 30a (see Fig. 5), and the dresser board 24 on the chuck table 26 is pressed against the grinding wheel 16 located above it, while the grinding wheel 14 and the chuck table 26 are each rotated about their orientation along the Z direction.

[0145] The dresser board 24 held by the chuck table 26 and the grinding wheel 16 are slid relative to each other to dress the grinding wheel 16. At this time, a liquid for dressing is supplied to the dresser board 24 from a liquid supply nozzle 46 (see FIGS. 3 and 4).

[0146] In this dressing step (step S30), a measuring step (step S40) and a load adjusting step (step S50) are further performed.

[0147] In the measurement step (step S40), the load applied to the dresser board 24 is continuously measured. This load can be grasped as a detected value by the load sensor 30b (see FIG. 5).

[0148] In the load adjustment step (step S50), the load output of the actuator 30a is adjusted based on the load measured in the measurement step (step S40). The chuck table 26 and the grinding wheel 16 are pressed against each other in a direction intersecting the sliding surface between the grinding wheel 16 and the dresser board 24 (direction along the Z direction) so that the load value detected by the load sensor 30b falls within a predetermined numerical range.

[0149] In this way, in the dressing section 8 of this embodiment, the grinding wheel 16 can be dressed by the dresser board 24 while adjusting the load between the grinding wheel 16 and the dresser board 24 to an appropriate value.

[0150] Furthermore, at this time, grinding of the workpiece 18 can also be performed simultaneously with the grinding wheel 16 (grinding process; step S60). The workpiece 18 is held on the holding surface 20a of the chuck table 20 of the workpiece handling unit 6, and the support base 22 is operated to position the chuck table 20 holding the workpiece 18 below the grinding wheel 14. In other words, the grinding wheel 14 of the grinding wheel handling unit 4, the chuck table 20 of the workpiece handling unit 6, and the chuck table 26 of the dressing unit 8 are positioned as shown in Figures 6 and 7.

[0151] In this state, the grinding wheel 14 and the chuck tables 20, 26 are rotated about an axis along the Z direction while the workpiece 18 on the chuck table 20 and the dresser board 24 on the chuck table 26 are both in contact with the lower end of the grinding stone 16 attached to the underside of the grinding wheel 14. This causes the dressing step (step S30) and the grinding step (step S60) to be performed simultaneously. At this time, a cleaning fluid is sprayed onto the grinding stone 16 from the cleaning nozzle 48 (see FIG. 7).

[0152] As grinding of the workpiece 18 progresses, the workpiece 18 becomes thinner, and accordingly, the surface of the workpiece 18 ground by the grinding wheel 16 moves downward. The position of the grinding wheel 14, which grinds the upper surface of the workpiece 18 by bringing the grinding wheel 16 into contact with the upper surface of the workpiece 18, moves in the Z direction (downward) toward the chuck table 20 by the operation of the moving part 12 provided in the grinding wheel handling part 4.

[0153] When dressing is performed simultaneously with grinding, the movement of the grinding surface (the sliding surface between the grinding wheel 16 and the workpiece 18) also means the movement of the dressing surface (the sliding surface between the grinding wheel 16 and the dresser board 24). Therefore, it is conceivable to retract the actuator 30a provided on the moving part 30 of the dressing unit 8 in accordance with the lowering of the dressing surface, thereby moving the dresser board 24 and the chuck table 26 downward.

[0154] However, the amount of descent of the grinding surface in one grinding operation (the amount of movement along the Z direction) is small. Therefore, in this embodiment, the movement of the dressing surface due to grinding performed simultaneously with dressing is absorbed by the operation of the biasing member 30j of the buffer unit 30f provided in the moving unit 30. In other words, instead of compressing the actuator 30a, the biasing member 30j, which is a helical spring, compresses, thereby pressing down the support base 28.

[0155] At this time, the pressing force generated between the grinding wheel 16 and the dresser board 24 increases as the biasing body 30j is compressed, but since the amount of descent of the grinding surface is small as described above, the amount of compression of the biasing body 30j is also small, and the change in pressing force can be ignored.

[0156] When adjusting the position of the chuck table 26 in the Z direction by a small distance by extending or retracting the actuator 30a, high precision is required for the extension or retraction of the actuator 30a. In this embodiment, instead, by providing a biasing member 30j, it is possible to eliminate the need for delicate control of the actuator 30a while allowing the dressing surface to move and allowing for suitable dressing to continue.

[0157] During the dressing step (step S30), for example, by retracting the chuck table 20 of the workpiece handling unit 6 downward relative to the grinding wheel 14, it is possible to dress only the grinding wheel 16 without grinding the workpiece 18. In other words, the dressing step (step S30) can be performed by bringing the dresser board 24 into contact with the grinding wheel 16 that is currently grinding the workpiece 18, or by bringing the dresser board 24 into contact with the grinding wheel 16 that is not currently grinding the workpiece 18.

[0158] Alternatively, the workpiece 18 can be brought into contact with the grinding wheel 16, but not with the dresser board 24, so that the workpiece 18 can be ground without dressing the grinding wheel 16.

[0159] In addition, using a procedure similar to the board thickness detection process (step S10), it is also possible to measure the value related to the thickness of the grinding wheel 16 (the distance from the bottom surface of the grinding wheel 14 to the bottom end of the grinding wheel 16) (grinding wheel thickness detection process; step S70), and use this in the distance adjustment process (step S20).

[0160] In the grinding wheel thickness detection process (step S70), the board holding unit (chuck table) 26 is moved in the Z direction by the moving unit 30, and information regarding the position of the chuck table 26 at the time when the chuck table 26 or the dresser board 24 held thereon comes into contact with the grinding wheel 16 is recorded.

[0161] The specific method is generally similar to the board thickness detection process (step S10), except that the grinding wheel 16 is assumed to be the object of contact as the chuck table 26 moves, instead of the measurement reference portion 44.

[0162] Alternatively, a similar procedure may be performed without holding the dresser board 24 on the chuck table 26, and instead of recording information regarding the position of the chuck table 26 at the time when the dresser board 24 comes into contact with the grinding wheel 16, information regarding the position of the chuck table 26, which is the board holding portion, at the time when the grinding wheel 16 comes into contact with the chuck table 26 may be recorded.

[0163] The grindstone thickness detection step (step S70) is performed, for example, in the following procedure before or after the grinding step (S60) or the grinding step simultaneous with the dressing step (steps S30 to S60) when these steps are repeatedly performed.

[0164] First, after one dressing and grinding process (steps S30 to S60) has been performed, or immediately after the grinding wheel 14 has been replaced, the grindstone thickness detection process (step S70) is performed once.

[0165] With the actuator 30a of the moving part 30 retracted, the dresser board 24 is held on the holding surface 26a of the chuck table 26. The position of the grinding wheel 14 in the Z direction is set to a position where the grinding stone 16 can grind the workpiece 18.

[0166] Next, the actuator 30a is extended. The dresser board 24 held by the chuck table 26 comes into contact with the lower end of the grinding wheel 16. The load sensor 30b detects the load, and the controller 50 records information about the position of the chuck table 26 at this time.

[0167] Subsequently, the dressing and grinding process (steps S30 to S60) is further performed, and then the grinding wheel thickness detection process (step S70) is performed again using the same procedure as above. In the first grinding wheel thickness detection process and the second grinding wheel thickness detection process, the position of the grinding wheel 14 in the Z direction is the same.

[0168] By comparing the information about the position of the chuck table 26 recorded in the first grinding wheel thickness detection process with the information about the position of the chuck table 26 recorded in the second grinding wheel thickness detection process, it is possible to determine the amount of wear of the grinding wheel 16 and the dresser board 24 in one dressing and grinding process (steps S30 to S60). This value can be used, for example, in determining the timing of switching between forward movement and air cutting in the distance adjustment process (step S20) performed before the dressing process (step S30).

[0169] In other words, for example, if one dressing and grinding process is performed and then another dressing and grinding process is performed, and the grinding wheel 14 is set to the same position in the Z direction in the first and second dressing and grinding processes, in the distance adjustment process before the second dressing and grinding process, the position of the chuck table 26 where the grinding wheel 16 and the dresser board 24 come into contact will be higher by the amount equal to the sum of the amounts of wear of the grinding wheel 16 and the dresser board 24 compared to the distance adjustment process before the first dressing and grinding process.

[0170] Therefore, when the dressing and grinding process (steps S30 to S60) is repeated using the same grinding wheel 16 and dresser board 24, it is advisable to delay the timing of switching between forward movement and air cutting in the previous distance adjustment process (step S20) each time by an amount corresponding to the amount of wear determined in the above-mentioned grinding wheel thickness detection process (step S70).

[0171] Alternatively, it is also possible to measure the thickness of the grinding wheel 16 itself, for example, by the grinding wheel thickness detection step (step S70). In this case, first, without the grinding wheel 16 attached to the grinding wheel 14, the chuck table 26 or the dresser board 24 held thereon is brought into contact with the grinding wheel 14 in the same manner as above, and information regarding the position of the chuck table 26 at that time is recorded.

[0172] Next, with the grinding wheel 16 attached to the grinding wheel 14, the chuck table 26 or the dresser board 24 is brought into contact with the grinding wheel 16 in the same manner, and information about the position of the chuck table 26 at that time is recorded. By comparing the information obtained at both times, the thickness of the grinding wheel 16 can be calculated.

[0173] After the grinding wheel 16 is dressed in the above-described dressing step and the workpiece 18 is ground by the grinding wheel 16, or after the grinding step is performed simultaneously with the dressing step and the workpiece 18 is ground by the grinding wheel 16, the workpiece 18, which is a semiconductor wafer, is divided into individual chips to manufacture the chips (dividing step; step S80). Figure 11 is a side view schematically showing one stage (dividing step) in the manufacture of chips.

[0174] In the dividing step (step S80), for example, a laser processing device 52 as shown in FIG. 11 is used, and the workpiece (wafer) 18 is divided by irradiating it with a laser beam.

[0175] The laser processing device 52 includes an irradiation unit 54 that irradiates the wafer 18 with a laser beam, and a holding mechanism 56 that holds the wafer 18 .

[0176] The irradiation unit 54 is a mechanism that guides and focuses a laser beam emitted from a laser oscillator (not shown) through an optical system including optical elements such as lenses and mirrors (not shown), and irradiates the laser beam onto the wafer 18 held by the holding mechanism 56.

[0177] The holding mechanism 56 is, for example, a chuck table, and is configured to hold the wafer 18, which is the workpiece, by suction. An upper surface 56a of the holding mechanism 56 forms a holding surface that holds the wafer 18. A negative pressure is supplied to the holding surface 56a from a suction source (not shown), thereby adsorbing the wafer 18, which is the workpiece, onto the holding surface 56a. A rotation mechanism (not shown) that rotates the holding mechanism 56 around a rotation axis that is aligned in the vertical direction is connected to the lower part of the holding mechanism 56.

[0178] In the example shown here, the wafer 18 is handled in the form of a frame unit attached to an annular frame via adhesive tape. The frame unit including the wafer 18 is held on the holding surface 56a of the holding mechanism 56, and a laser beam of a wavelength that is absorbed by the material of the wafer 18 is irradiated. The laser beam is adjusted by a condenser lens provided in the irradiation unit 54 to have a focal point at a target position on the wafer 18, and then irradiated.

[0179] While the laser beam is being irradiated onto the wafer 18, the holding mechanism 56 and the irradiation unit 54 move relatively in a direction along the holding surface 56a, thereby subjecting the wafer 18 to ablation processing along the planned dividing lines set in a grid pattern on the wafer 18. In this way, the wafer 18 is divided into individual chips, and the chips are manufactured.

[0180] In the dividing step (step S80), grooves along the planned dividing lines may be formed in the wafer 18 by laser ablation processing, and then the wafer 18 may be divided along the grooves by applying an external force, or a modified layer along the planned dividing lines may be formed in the material of the wafer 18 by irradiating it with a laser beam, and then the wafer 18 may be divided along the modified layer. In this case, the grooves or modified layer formed in the wafer 18 function as dividing starting points.

[0181] The step of forming the division starting points on the wafer 18 may be performed at any time before the dividing step. For example, the division starting points may be formed after the grinding step (step S50), or the grinding step may be performed on the wafer 18 on which the division starting points have been formed in advance.

[0182] Alternatively, the dividing step (step S80) may be performed using a cutting device, which includes, for example, a cutting unit and a holding mechanism.

[0183] The cutting unit includes a spindle to which a cutting blade is attached and a housing that rotatably supports the spindle. The cutting blade includes, for example, an annular base and an annular cutting edge attached along the outer periphery of the base.

[0184] The spindle is cylindrical, has one end equipped with a blade mount to which the cutting blade is attached, and has the other end equipped with a rotational drive source such as a motor. The cylindrical spindle is housed in a housing with its axis aligned horizontally, and when the rotational drive source is activated, it rotates together with the cutting blade around the horizontal axis.

[0185] During cutting, the cutting blade cuts into the wafer 18 held by the holding mechanism while rotating together with the spindle. While the cutting blade cuts into the wafer 18, the cutting unit and the holding mechanism move relatively in a direction along the holding surface, thereby dividing the wafer 18 along the planned dividing line. Alternatively, after the cutting blade forms a cutting groove in the wafer 18 along the planned dividing line, the wafer 18 may be divided along the cutting groove by a method such as applying an external force.

[0186] Other division methods include, for example, a method in which a wafer 18 having grooves formed on its surface by laser ablation, cutting, or other methods is ground from the surface (back surface) opposite to the surface on which the grooves are formed (front surface) to thin the wafer 18 to a thickness that exposes the grooves on the back surface. Alternatively, a wafer 18 having grooves or modified layers formed thereon can be similarly ground, and in addition to thinning the wafer 18, an external force is applied to the wafer 18 during grinding, causing the wafer 18 to be divided from the grooves or modified layers as starting points. When division is performed by these methods, the division process and the grinding process are carried out simultaneously.

[0187] Furthermore, when chips are manufactured from the wafer 18, other processes such as ultraviolet irradiation and film formation may be carried out as appropriate before or after division.

[0188] The procedure shown in FIG. 8 is merely an example, and the steps described here may be rearranged, omitted, or additional steps may be added, or the content of the steps may be changed. For example, the board thickness detection step (step S10) and the grindstone thickness detection step (step S70) may be performed at any timing other than those described above. Although the dividing step (step S80) is shown after the stone thickness detection step (step S70), the dividing step may be performed before the detection step, or may be performed in parallel with the detection step. As explained above, the dividing step may also be performed simultaneously with the grinding step.

[0189] In each of the above steps shown in FIG. 8, for example, the extension and contraction operation of the actuator 30a in the board thickness detection step (step S10) and the grinding wheel thickness detection step (step S70), the adjustment of the pressing force by the actuator 30a in the load adjustment step (step S50), the setting of the movement speed of the chuck table 26 in the distance adjustment step (step S20), and the setting of the position or timing to start air cutting may be performed by a human (operator) inputting an operation through the input / output unit 50d, or may be performed automatically by the controller 50.

[0190] When the controller 50 executes these processes, for example, information relating to the position of the chuck table 26 obtained in the board thickness detection process (step S10) and the grindstone thickness detection process (step S70) is stored in the memory unit 50b, and the calculation unit 50a uses this information to set the start position of the air cut in the distance adjustment process (step S20), etc. Based on this, the controller 50 adjusts the operation and output of each unit, inputs control signals to each unit through the communication unit 50c, and executes the distance adjustment process (step S20), dressing process (step S30), load adjustment process (step S50), etc.

[0191] The structures, methods, etc. according to the above-described embodiments are not limited to the above-described embodiments, and may be modified as appropriate without departing from the scope of the object of the present invention. [Explanation of symbols]

[0192] 2: Dressing device, 4: Grinding wheel handling section, 6: Workpiece handling section, 8: Dressing section 10: Grinding operation part (spindle), 12: Moving part, 14: Grinding wheel, 16: Grinding stone 18: Workpiece (wafer) 20: workpiece holding portion (chuck table), 20a: holding surface 22: Support stand 24: Dresser board, 26: Board holding part (chuck table), 26a: Holding surface 28: Support stand, 30: Moving unit, 30a: Actuator, 30b: Measuring unit (load sensor) 30c: Main body, 30d: Rod, 30e: Tip (thin diameter part), 30f: Buffer part 30g: guide pin, 30h: pressing body, 30i: spacing portion, 30j: biasing body 32: Seal unit, 34: Rotation drive unit (servo motor) 36: Transmission unit (belt), 38: Auxiliary support unit (fluid pressure cylinder), 40: Base 42: Guide portion, 42a: Sheath portion, 42b: Pillar portion, 44: Measurement reference portion 46: Liquid supply nozzle, 48: Cleaning nozzle 50: Controller, 50a: Calculation unit, 50b: Storage unit, 50c: Communication unit 50d: Input / output section 52: laser processing device, 54: irradiation unit, 56: holding mechanism, 56a: holding surface

Claims

1. A dressing device that dresses a grinding wheel that grinds a workpiece by sliding the grinding wheel and a dresser board relative to each other, a board holding portion that holds the dresser board; a moving unit that moves the board holding unit and the grinding wheel relatively in a direction that intersects with a sliding surface between the grinding wheel and the dresser board; A measuring unit that measures a load applied to the dresser board. Dressing device.

2. the moving portion is configured to move the board holder relative to the grinding wheel; Further provided is a measurement reference portion disposed on a trajectory of movement of the dresser board by the moving portion. The dressing device according to claim 1 .

3. The moving unit includes an actuator that moves the board holding unit relative to the grinding wheel, a guide portion that limits movement of the board holding portion in a direction intersecting a direction in which the actuator moves the board holding portion, The dressing device according to claim 1 or 2.

4. a workpiece holder that holds the workpiece; a grinding operation unit to which a grinding wheel having the grinding stone is rotatably mounted, The grinding wheel is configured to rotate the grinding stone and bring the grinding stone into contact with the workpiece held by the workpiece holder, thereby grinding the workpiece; and The dresser is configured to be able to dress the grinding wheel by bringing the grinding wheel into contact with the dresser board held by the board holding part while rotating the grinding wheel by operating the grinding wheel. The dressing device according to claim 1 or 2.

5. The dresser board is configured to bring the grinding wheel, which rotates due to the operation of the grinding wheel, into contact with the dresser board, so as to dress the grinding wheel, in either a state in which the workpiece is not being ground by the grinding wheel, or a state in which the workpiece held in the workpiece holding section is being ground by the grinding wheel. The dressing device according to claim 4.

6. a liquid supply nozzle that supplies liquid to the dresser board held by the board holder; The dressing device according to claim 1 or 2.

7. Further, a cleaning nozzle is provided for supplying a fluid to the grinding wheel; the grinding wheel, the workpiece holding portion, and the board holding portion are arranged so that a locus of the grinding stone, which rotates as the grinding wheel rotates, partially overlaps the workpiece held in the workpiece holding portion and partially overlaps the dresser board held in the board holding portion when viewed from a direction perpendicular to the rotation plane of the grinding stone; the cleaning nozzle is arranged to supply fluid at a position on the trajectory of the grinding wheel that does not come into contact with either the workpiece held in the workpiece holding section or the dresser board held in the board holding section, when viewed from a direction perpendicular to the rotation plane of the grinding wheel. The dressing device according to claim 1 or 2.

8. A dressing method for performing a dressing step of dressing a grinding wheel using a dressing device that includes a board holding unit that holds a dresser board and that slides the dresser board held by the board holding unit and a grinding wheel that grinds a workpiece relative to each other, comprising: In the dressing step, a measuring step of measuring a load applied to the dresser board; a load adjusting step of pressing the board holding part and the grinding wheel against each other in a direction intersecting the sliding surfaces of the grinding wheel and the dresser board so that the value of the load measured in the measuring step falls within a predetermined numerical range; How to dress.

9. The dressing device includes: a moving unit that moves the board holding unit relative to the grinding wheel in a direction that intersects with a sliding surface between the grinding wheel and the dresser board; a measurement reference unit disposed on a trajectory of movement of the dresser board by the moving unit; a board thickness detection step of moving the board holding unit by the moving unit and recording information about the position of the board holding unit at the time when the dresser board held by the board holding unit comes into contact with the measurement reference unit; and a distance adjustment step of controlling the amount of movement of the board holding unit by the movement unit based on information about the position of the board holding unit recorded in the board thickness detection step. The dressing method according to claim 8.

10. The dressing device includes: a dressing device further including a moving part that moves the board holding part relative to the grinding wheel in a direction that intersects with a sliding surface between the grinding wheel and the dresser board; a grinding wheel thickness detection step of moving the board holding unit by the moving unit and recording information about the position of the board holding unit at the time when the board holding unit or the dresser board held by the board holding unit comes into contact with the grinding wheel; and a distance adjustment step of controlling the amount of movement of the board holding unit by the movement unit based on information about the position of the board holding unit recorded in the grindstone thickness detection step. The dressing method according to claim 8.

11. The dressing step includes: by contacting the dresser board with the grinding wheel while grinding the workpiece; or The dresser board is brought into contact with the grinding wheel when the grinding wheel is not grinding the workpiece. The dressing method according to claim 8.

12. A method for producing chips by dividing a workpiece, comprising the steps of: a dressing step in which the dressing device includes a board holding section for holding a dresser board, and the dresser board held by the board holding section and the grinding wheel for grinding a workpiece are dressed using the dressing device by sliding the dresser board held by the board holding section relative to each other; a grinding step in which the workpiece is ground with the grinding wheel dressed in the dressing step, or in which the grinding wheel is dressed in the dressing step and the workpiece is ground with the grinding wheel at the same time; a dividing step of dividing the workpiece to form chips after the grinding step; Equipped with In the dressing step, a measuring step of measuring a load applied to the dresser board; a load adjusting step of pressing the board holding part and the grinding wheel against each other in a direction intersecting a contact surface between the grinding wheel and the dresser board so that the value of the load measured in the measuring step falls within a predetermined numerical range; How chips are manufactured.

13. The method for manufacturing a chip according to claim 12, wherein in the dividing step, the workpiece is divided along dividing starting points formed on the workpiece to form chips.

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