JP7715604B2 - Grinding equipment - Google Patents

Description

The present invention relates to a grinding device that includes a holding unit and a grinding wheel, and that moves the holding unit, which holds a workpiece, under the grinding wheel that moves on a circular track, and grinds the workpiece with the grinding wheel.

The manufacturing process for device chips used in electronic devices such as mobile phones and personal computers begins with preparing multiple chips made of semiconductors or other materials, each equipped with devices such as ICs (Integrated Circuits) and LSIs (Large-scale Integration). The multiple chips are then aligned and integrated by sealing them with molding resin. The resulting package substrate is then divided into individual chips, forming the individual device chips.

In recent years, there has been a significant trend toward space-saving electronic devices equipped with device chips, and demand for thinner device chips is also increasing. Therefore, in order to manufacture thinner device chips, the package substrate is ground from the back side (the mold resin side) to thin it before being separated. The grinding device used to grind the package substrate includes a holding unit (e.g., a chuck table) that can hold the workpiece by suction, and grinding wheels arranged in a ring shape.

In a grinding device, for example, a grinding process known as creep feed grinding is performed on a workpiece. When performing creep feed grinding, the bottom surface of the grinding wheel is first lowered below the height of the workpiece's surface (top surface), and the grinding wheel is rotated in a plane approximately parallel to the top surface of the holding unit. The holding unit holding the workpiece is then moved below the rotating grinding wheel, and the side and bottom surfaces of the grinding wheel are brought into contact with the workpiece to perform grinding (see Patent Document 1).

When a workpiece is ground, the grinding wheel gradually wears down and becomes thinner, causing the bottom surface of the grinding wheel to rise. As a result, if left unchecked, the height of the bottom surface of the grinding wheel at the end of grinding will be higher than the height of the bottom surface of the grinding wheel at the start of grinding the workpiece's surface. Therefore, a method has been developed to reduce unevenness in the thickness of the ground workpiece by checking the wear tendency of the grinding wheel in advance and gradually lowering the grinding wheel by an amount corresponding to the amount of wear during creep feed grinding (see Patent Document 2).

A method is also known in which multiple workpieces are placed on a holding unit and creep feed grinded to different thicknesses (see Patent Document 3). In this method, the height of the grinding wheel is changed to match the finish thickness set for each workpiece to be ground.

To achieve this type of grinding, a large gap must be provided between two adjacent workpieces on the holding unit. Otherwise, when grinding one workpiece, the grinding wheel may come into contact with the other workpiece, resulting in the other workpiece being thinned to a thickness different from the finish thickness set for that workpiece.

JP 2010-16181 A Japanese Patent Application Laid-Open No. 2016-2598 Japanese Patent Application Laid-Open No. 2020-89930

However, if the holding unit is made relatively large to ensure sufficient distance between multiple workpieces when they are placed on it, the grinding device itself will also become larger. Large grinding devices have relatively high manufacturing and operating costs. Furthermore, for example, if a grinding device installed in a clean room becomes large, it will not only take up space in the clean room but also increase the operating costs of the clean room. Therefore, there is a demand for a smaller grinding device that performs creep feed grinding to grind multiple workpieces to different thicknesses.

The present invention was made in consideration of these problems, and its purpose is to provide a compact grinding device that can creep feed grind multiple workpieces so that each has a different thickness.

According to one aspect of the present invention, there is provided a grinding apparatus comprising: a holding unit having a holding surface for holding a plurality of workpieces; a grinding unit in which grinding wheels are disposed for grinding the upper surfaces of the plurality of workpieces held by the holding unit; and a lifting unit for raising and lowering the grinding unit in a direction perpendicular to the holding surface, wherein the holding unit comprises a plurality of accommodating recesses exposed on the holding surface, a plurality of holding tables respectively accommodated in the accommodating recesses , a plurality of table lifting mechanisms accommodated in the plurality of accommodating recesses respectively for raising and lowering the respective holding tables in a direction perpendicular to the holding surface, and a lifting unit for relatively moving the holding unit and the grinding unit in a direction parallel to the holding surface. and a horizontal movement unit configured to move the holding units so as to hold the plurality of workpieces placed on the upper surfaces of the respective holding tables, and to operate the respective table lifting mechanisms to independently adjust the heights of the plurality of holding tables in accordance with the finished thicknesses of the workpieces held by the respective holding tables , and to operate the horizontal movement units to creep feed grind the upper surfaces of the plurality of workpieces held on the respective holding tables from one end side to the other end side with the grinding wheels , thereby enabling each of the workpieces, the upper surfaces of which are not uniform in height before creep feed grinding, to be brought to the respective finished thicknesses.

Preferably, the holding unit further includes an inclination adjustment mechanism for adjusting the inclination of the upper surface of the holding table relative to the grinding wheel.

Also, preferably, the workpiece has a first layer and a second layer overlying the first layer,
The workpieces are held by the respective holding tables from the first layer side, and the heights of the respective holding tables are adjusted so that the thicknesses of the second layers of all the workpieces are uniform when the workpieces are creep feed ground with the grinding wheels, and the workpieces are creep feed ground with the grinding wheels.

Preferably, the grinding unit can simultaneously creep feed grind two or more of the plurality of workpieces held by the holding unit with the grinding wheel.

In one aspect of the grinding device of the present invention, a holding unit is provided with multiple holding tables, each of which can be adjusted in height independently. Multiple workpieces are held by each holding table, and the height of each holding table is adjusted according to the finish thickness set for each workpiece. The grinding unit then creep feed grinds the top surface of each workpiece. As a result, each workpiece has a thickness that corresponds to the distance between each holding table and the grinding wheel. In other words, the grinding device of this aspect of the present invention can simultaneously grind multiple workpieces to different finish thicknesses.

In this case, there is no need to change the height of the grinding unit for each workpiece to be ground, and no problems arise even if two or more workpieces are ground simultaneously with the grinding wheel. Therefore, there is no need to ensure large gaps between each holding table, and there is no need to enlarge the holding unit. As a result, there is no need to enlarge the grinding device.

Therefore, the present invention provides a compact grinding device that can creep feed grind multiple workpieces to different thicknesses.

FIG. 2 is a perspective view schematically showing a grinding device. FIG. 2 is a perspective view schematically showing a holding unit. FIG. 2 is a cross-sectional view schematically showing a holding unit. FIG. 4(A) is a perspective view schematically showing a table lifting mechanism, FIG. 4(B) is a perspective view schematically showing a tilt adjustment mechanism, and FIG. 4(C) is a perspective view schematically showing a table adjustment mechanism. FIG. 3 is a cross-sectional view schematically showing a holding unit that holds a workpiece. FIG. 2 is a cross-sectional view schematically showing a workpiece that has been creep feed ground.

An embodiment of the present invention will be described with reference to the drawings. Figure 1 is a perspective view showing a grinding device 2 according to this embodiment. The grinding device 2 according to this embodiment is capable of creep feed grinding multiple workpieces 1 simultaneously. First, the workpieces 1 to be ground by the grinding device 2 will be described.

The workpiece 1 is a rectangular package substrate comprising a substrate made of Si (silicon), SiC (silicon carbide), or other semiconductor material with devices such as ICs or LSIs mounted on its surface, and a molding resin that seals the substrate. For example, the package substrate can be ground to a predetermined thickness and then divided into individual devices to obtain individual device chips. However, the workpiece 1 is not limited to this.

Next, we will explain the grinding device 2 according to this embodiment. Figure 1 is a perspective view that schematically shows the grinding device 2. The grinding device 2 has a roughly rectangular parallelepiped base 4 that supports each component. A recess 4a is formed on the top surface of the base 4 along the Y-axis direction. The recess 4a is provided with a holding unit 6 that is movable in the Y-axis direction and can hold multiple workpieces 1, and a dust-proof and drip-proof cover 4b that covers the opening of the recess 4a while exposing the holding unit 6. The top surface of the holding unit 6 forms a holding surface 38 on which the workpieces 1 rest.

A Y-axis movement mechanism (not shown) that movably supports the holding unit 6 is disposed inside the recess 4a. For example, the Y-axis movement mechanism is a ball screw type movement mechanism that functions to move the holding unit 6 in the Y-axis direction. Alternatively, the grinding device 2 may be equipped with a Y-axis movement mechanism that moves the grinding unit 8 (described below) in the Y-axis direction instead of the holding unit 6.

That is, the Y-axis movement mechanism (horizontal movement unit) moves the holding unit 6 and the grinding unit 8 relatively in a direction parallel to the holding surface 38 (the Y-axis direction). The holding unit 6 will be described in more detail below.

The grinding device 2 includes a grinding unit 8 that grinds the workpiece 1 held by the holding unit 6, and a lifting unit 12 that raises and lowers the grinding unit 8. A support part 10 is erected at the rear of the grinding device 2, and this support part 10 supports the grinding unit 8 via the lifting unit 12. A pair of guide rails 14 are provided on the front of the support part 10, extending along the Z-axis direction (vertical direction). A movable plate 16 is slidably attached to each guide rail 14.

A nut (not shown) is provided on the back side (rear side) of the moving plate 16, and a ball screw 18 parallel to the guide rail 14 is threadedly engaged with this nut. A pulse motor 20 is connected to one end of the ball screw 18. When the pulse motor 20 rotates the ball screw 18, the moving plate 16 moves in the Z-axis direction along the guide rail 14.

A grinding unit 8, which performs grinding on the workpiece 1, is fixed to the front side of the movable plate 16. By operating the lifting unit 12 to move the movable plate 16, the grinding unit 8 can move along the Z-axis direction. In other words, the lifting unit 12 has the function of raising and lowering the grinding unit 8 in a direction approximately perpendicular to the holding surface 38 of the holding unit 6.

The grinding unit 8 has a cut cylindrical holding member 22. The holding member 22 is fixed to the front surface of the moving plate 16. A spindle housing 24 is provided inside the holding member 22. The spindle housing 24 is supported on the bottom wall of the holding member 22 via an annular buffer member (not shown) made of rubber or the like.

A portion of the spindle 26 is rotatably housed in the spindle housing 24. A rotation drive mechanism (not shown), such as a motor, is connected to the upper end of the spindle 26. When the rotation drive mechanism is operated, the spindle 26 rotates. Note that the orientation of the spindle 26 does not need to be strictly along the Z-axis direction; the tilt angle of the spindle 26 from the Z-axis direction may be set to a predetermined value. For example, the tilt angle of the grinding unit 8 from the direction perpendicular to the holding surface 38 of the holding unit 6 is adjustable.

The lower end of the spindle 26 is located below the bottom of the holding member 22. The upper surface of a disk-shaped wheel mount 28 is connected to the lower end of the spindle 26. The upper surface of an annular grinding wheel 30 is attached to the lower surface of the wheel mount 28.

The grinding wheel 30 has an annular wheel base 32. The wheel base 32 is made of a metal such as aluminum and has a diameter corresponding to the diameter of the holding surface 38 of the holding unit 6. The upper surface of this wheel base 32 is connected to the lower surface of the wheel mount 28. In other words, the grinding wheel 30 is attached to the spindle 26 via the wheel mount 28.

A plurality of grinding wheels 34 are provided on the underside of the wheel base 32. Each grinding wheel 34 is formed by mixing abrasive grains such as diamond or cBN (cubic boron nitride) with a binder such as vitrified or resinoid, and then sintering the mixture. When the spindle 26 is rotated to rotate the grinding wheel 30, the grinding wheels 34 rotate and move on an annular orbit.

Creep feed grinding is known as a method for grinding the workpiece 1 to a predetermined thickness. In creep feed grinding, the bottom surface of the grinding wheel 34 is first positioned lower than the surface (top surface) of the workpiece 1 to be ground, and the grinding wheel 34 is rotated in a plane approximately parallel to the holding surface 38 of the holding unit 6. The holding unit 6, which holds the workpiece 1, is then moved in a direction parallel to the holding surface 38 (Y-axis direction) to be placed below the rotating grinding wheel 34, and the sides and bottom of the grinding wheel 34 are brought into contact with the workpiece 1 to perform grinding.

A known method involves placing multiple workpieces 1 of different thicknesses on the holding surface 38 of the holding unit 6 and performing creep feed grinding to achieve different thicknesses. In this method, the height of the grinding wheel 34 is adjusted to match the workpiece 1 being ground. That is, when the grinding wheel 34 overlaps the unmachined workpiece 1 while the holding unit 6 is being moved, the lifting unit 12 is operated to change the height of the bottom surface of the grinding wheel 34. The height of the bottom surface of the grinding wheel 34 at this time is determined based on the finished thickness of the workpiece 1.

If, during creep feed grinding of a workpiece 1 with a certain finish thickness, the grinding wheel 34 comes into contact with another workpiece 1 with a thicker finish thickness, the other workpiece 1 will be excessively thinned. Therefore, in order to grind multiple workpieces 1 with different finish thicknesses, it is necessary to ensure a wide gap between two adjacent workpieces 1 on the holding unit 6. This gap is set to a size that prevents the grinding wheel 34 grinding one workpiece 1 from coming into contact with the other workpiece 1 as it rotates around the circular orbit.

However, in a holding unit 6 capable of holding multiple workpieces 1, if the workpieces 1 need to be spaced apart sufficiently, the holding surface 38 of the holding unit 6 must be made larger. Increasing the size of the holding unit 6 results in the grinding device 2 itself becoming larger, increasing the area occupied by the grinding device 2. For example, if the grinding device 2 is placed in a clean room, it will take up space in the clean room, making it difficult to install other devices. This reduces the operating efficiency of the clean room. Furthermore, a large grinding device 2 requires significant manufacturing and operation costs.

Therefore, there is a demand for a more compact grinding device 2 that performs creep feed grinding on multiple workpieces 1 so that each has a different thickness. Therefore, the grinding device 2 according to this embodiment was developed as a grinding device that can creep feed grind multiple workpieces 1 so that each has a different thickness without increasing the size of the device configuration.

Figure 2 is a perspective view schematically showing the holding unit 6 of the grinding device 2 according to this embodiment. Figure 3 is a cross-sectional view schematically showing the holding unit 6. In the grinding device 2 according to this embodiment, the holding unit 6 includes multiple holding tables 40, each exposed on the holding surface 38. In the example shown in Figure 2 and other figures, the holding unit 6 includes a first holding table 40a, a second holding table 40b, and a third holding table 40c, and is capable of holding three workpieces 1. However, the number of holding tables 40 is not limited to this.

The holding unit 6 includes a frame 36 made of aluminum, stainless steel, or the like that houses each component. The frame 36 includes storage recesses 46a, 46b, and 46c exposed on a holding surface 38 that can house the holding tables 40a, 40b, and 40c, respectively. A suction source 48, such as a pump or ejector, is connected to the frame 36 via a suction path 52. One end of the suction path 52 is connected to the suction source 48, and the other end branches off, connects to the bottom of the frame 36, and leads to the bottom of the storage recesses 46a, 46b, and 46c.

Each of the branched suction paths 52 is provided with on-off valves 50a, 50b, and 50c, such as solenoid valves. Activating the on-off valves 50a, 50b, and 50c switches between supplying and halting the negative pressure generated by the suction source 48 to each of the storage recesses 46a, 46b, and 46c.

The holding unit 6 also includes multiple table lifting mechanisms 54a, 54b, and 54c for raising and lowering the respective holding tables 40a, 40b, and 40c in a direction perpendicular to the holding surface 38 (the Z-axis direction). Furthermore, the holding unit 6 further includes multiple tilt adjustment mechanisms 62a, 62b, and 62c for adjusting the tilt of the holding surface 38 (the upper surfaces of the respective holding tables 40a, 40b, and 40c) relative to the grinding wheel 34.

Table lifting mechanisms 54a, 54b, 54c are supported and housed in the respective storage recesses 46a, 46b, 46c by the frame 36, and tilt adjustment mechanisms 62a, 62b, 62c are supported and housed by the table lifting mechanisms 54a, 54b, 54c. The holding tables 40a, 40b, 40c are supported by the tilt adjustment mechanisms 62a, 62b, 62c and housed in the storage recesses 46a, 46b, 46c.

Figure 4(A) is a perspective view schematically illustrating a portion of the table lifting mechanisms 54a, 54b, and 54c supported by the frame 36 at the bottom of the storage recesses 46a, 46b, and 46c. The table lifting mechanisms 54a, 54b, and 54c include piezoelectric actuators 56a, 56b, and 56c provided in the center of the bottom.

Piezoelectric actuators 56a, 56b, and 56c are electrically connected to a control unit (not shown) of the grinding device 2, and expand and contract in response to electrical signals supplied from the control unit. Base plates 58a, 58b, and 58c (see Figure 4(B)) of tilt adjustment mechanisms 62a, 62b, and 62c are placed on the upper ends of piezoelectric actuators 56a, 56b, and 56c, and when each piezoelectric actuator 56a, 56b, and 56c is operated, base plates 58a, 58b, and 58c rise and fall.

Figure 4(B) is a perspective view schematically showing the tilt adjustment mechanisms 62a, 62b, and 62c supported by the table lifting mechanisms 54a, 54b, and 54c. The tilt adjustment mechanisms 62a, 62b, and 62c include three piezoelectric actuators 64a, 64b, and 64c that are not aligned in a straight line on the upper surfaces of the base plates 58a, 58b, and 58c. These three piezoelectric actuators 64a, 64b, and 64c are electrically connected to the control unit of the grinding device 2 and expand and contract in response to electrical signals supplied from the control unit.

Holding tables 40a, 40b, and 40c are placed on the upper ends of the three piezoelectric actuators 64a, 64b, and 64c, respectively. By operating each piezoelectric actuator 64a, 64b, and 64c and independently controlling its length, the tilt of holding tables 40a, 40b, and 40c can be adjusted.

Figure 3 and other figures show cross-sectional views of the holding tables 40a, 40b, and 40c supported by the tilt adjustment mechanisms 62a, 62b, and 62c. The holding tables 40a, 40b, and 40c have porous members 42a, 42b, and 42c exposed on the holding surface 38, and table frames 44a, 44b, and 44c that house the porous members 42a, 42b, and 42c.

In addition, vertically penetrating ventilation holes 66a, 66b, 66c are formed in the bottom plates of the table frames 44a, 44b, 44c. Vertically penetrating ventilation holes 60a, 60b, 60c are also formed in the base plates 58a, 58b, 58c. There are no restrictions on the positions of the ventilation holes 66a, 66b, 66c and the ventilation holes 60a, 60b, 60c.

As shown in Figure 5, when workpieces 1a, 1b, and 1c are placed on each holding table 40a, 40b, and 40c and suction source 48 is activated, negative pressure is applied to workpieces 1a, 1b, and 1c through vents 60a, 60b, and 60c and vents 66a, 66b, and 66c. In other words, workpieces 1a, 1b, and 1c can be held by suction on each holding table 40a, 40b, and 40c of holding unit 6.

In the grinding device 2 according to this embodiment, the heights of the multiple holding tables 40a, 40b, and 40c can be adjusted independently by operating the respective table lifting mechanisms 54a, 54b, and 54c. Figures 2 and 5 schematically show a holding unit 6 in which the heights of the holding tables 40a, 40b, and 40c are adjusted independently of one another.

Next, a method for simultaneously grinding multiple workpieces 1a, 1b, 1c having different finished thicknesses using the grinding device 2 according to this embodiment will be described with reference to Figures 5 and 6. Here, each workpiece 1a, 1b, 1c has, for example, a first layer 3a, 3b, 3c and a second layer 5a, 5b, 5c that overlaps the first layer 3a, 3b, 3c. For example, the first layers 3a, 3b, 3c are wiring boards, and the second layers 5a, 5b, 5c are semiconductor chips. However, the type of each workpiece 1a, 1b, 1c and the number of layers provided are not limited to these.

These layers vary in thickness. In this explanation, creep feed grinding is performed so that the thicknesses of the second layers 5a, 5b, and 5c of all workpieces 1a, 1b, and 1c are uniform when the workpieces 1a, 1b, and 1c are ground.

First, before each workpiece 1a, 1b, 1c is loaded into the grinding device 2, the thickness of each layer of each workpiece 1a, 1b, 1c is measured using a thickness gauge. Next, each workpiece 1a, 1b, 1c is loaded into the holding unit 6 and placed on each holding table 40a, 40b, 40c. Then, the suction source 48 is activated, and each holding table 40a, 40b, 40c holds the workpieces 1a, 1b, 1c from the side of the first layers 3a, 3b, 3c.

Then, the table lifting mechanisms 54a, 54b, and 54c are operated to adjust the height of each holding table 40a, 40b, and 40c. For example, when multiple workpieces 1a, 1b, and 1c are ground with the grinding wheel 34, the height of each holding table 40a, 40b, and 40c is adjusted so that the thicknesses of the second layers 5a, 5b, and 5c of all workpieces 1a, 1b, and 1c are uniform.

Furthermore, if there is thickness non-uniformity in the first layers 3a, 3b, 3c or second layers 5a, 5b, 5c of the workpieces 1a, 1b, 1c, the tilt of the workpieces 1a, 1b, 1c may be adjusted to reduce the effect of this non-uniformity on the processing results. In this case, the tilt of the holding tables 40a, 40b, 40c is adjusted by independently operating the multiple piezoelectric actuators 64a, 64b, 64c that make up the tilt adjustment mechanisms 62a, 62b, 62c.

Figure 5 shows a schematic of holding tables 40a, 40b, and 40c with their heights adjusted. At this time, the lifting unit 12 is operated so that the bottom end of the grinding wheel 54 is positioned at a height position 9 that is higher than the bottom end of the second layers 5a, 5b, and 5c by the finishing thickness 7 of the second layers 5a, 5b, and 5c. Here, the finishing thickness of each workpiece 1a, 1b, and 1c changes by the difference in thickness between the first layers 3a, 3b, and 3c.

Furthermore, the tilt of the spindle 26 is adjusted so that the spindle 26 is tilted at a predetermined angle from the direction perpendicular to the holding surface 38 of the holding unit 6 (Z-axis direction). Tilting the spindle 26 tilts the circular orbit of the grinding wheel 34 that rotates when the spindle 26 is rotated. In this case, the grinding wheel 34 grinds the workpiece 1 when passing through a relatively low position on the circular orbit, and is less likely to come into contact with the workpiece 1 when passing through a relatively high position on the circular orbit. This may improve the flatness of the ground surface of the workpiece 1.

Alternatively, the tilt of the spindle 26 can be adjusted to align the spindle 26 perpendicular to the holding surface 38 of the holding unit 6 (in the Z-axis direction). In this case, the circular orbit of the grinding wheel 34 that rotates when the spindle 26 is rotated becomes parallel to the holding surface 38. When the workpiece 1 is ground with the grinding wheel 34 in this state, the flatness of the ground surface of the workpiece 1 may be improved.

Next, as shown in Figure 6, the spindle 26 is rotated to rotate the grinding wheel 34 on the circular orbit, and the Y-axis movement mechanism (horizontal movement unit) is operated to move the holding unit 6 from its initial position and pass below the grinding wheel 34. Figure 6 schematically shows the state in which the holding unit 6 has been returned to its initial position after each workpiece 1a, 1b, 1c has been ground by the grinding wheel 34 to its respective finishing thickness.

More specifically, first, the rotating grinding wheel 34 comes into contact with the second layer 5c of the third workpiece 1c, grinding the third workpiece 1c. Then, the grinding wheel 34 comes into contact with the second layer 5b of the second workpiece 1b, grinding the second workpiece 1b. At this time, there is no problem if the rotating grinding wheel 34 comes into contact with the third workpiece 1c as it passes over it.

Furthermore, the grinding wheel 34 then comes into contact with the second layer 5a of the first workpiece 1a, grinding the first workpiece 1a. At this time, there is no problem if the grinding wheel 34 comes into contact with the second workpiece 1b as it passes over it. In this way, the top surfaces of the workpieces 1a, 1b, and 1c are creep feed ground by the grinding wheel 34 from one end to the other.

In other words, in the grinding device 2 according to this embodiment, the grinding wheels 34 grind the multiple workpieces 1a, 1b, and 1c held on the respective holding tables 40a, 40b, and 40c, thereby grinding each of the workpieces 1a, 1b, and 1c to their respective finishing thicknesses. At this time, the grinding unit 8 can simultaneously grind two or more of the multiple workpieces 1a, 1b, and 1c held by the holding unit 6 with the grinding wheels 34.

As explained above, when using the grinding device 2 according to this embodiment, when simultaneously creep feed grinding multiple workpieces 1 with different finish thicknesses, there is no need to change the height of the grinding unit 8 for each workpiece 1. Furthermore, because there is no problem if the grinding wheel 34 grinding one workpiece 1 comes into contact with another adjacent workpiece 1, there is no need to ensure large gaps between the holding tables 40a, 40b, and 40c, and there is no need to enlarge the holding unit 6. Therefore, there is no need to enlarge the grinding device 2.

The present invention is not limited to the above embodiment and can be implemented with various modifications. For example, in the above embodiment, the holding unit 6 is described as including table lifting mechanisms 54a, 54b, and 54c that adjust the height of each holding table 40a, 40b, and 40c, and tilt adjustment mechanisms 62a, 62b, and 62c that adjust the tilt. However, the grinding device 2 according to one aspect of the present invention is not limited to this.

For example, the grinding device 2 may be equipped with a table adjustment mechanism 68 that combines the functions of a table lifting mechanism and an inclination adjustment mechanism. Figure 4(C) is a perspective view that schematically shows the table adjustment mechanism 68. As shown in Figure 4(C), the table adjustment mechanism 68 is composed of, for example, six piezoelectric actuators 70. The table adjustment mechanism 68 can simultaneously adjust the height and inclination of the holding tables 40a, 40b, and 40c by independently operating the six piezoelectric actuators 70 to expand and contract.

The structures, methods, etc. described in the above embodiments can be modified as appropriate without departing from the scope of the present invention.

REFERENCE SIGNS LIST 1, 1a, 1b, 1c Workpiece 3a, 3b, 3c First layer 5a, 5b, 5c Second layer 7 Finishing thickness 9 Height position 2 Grinding device 4 Base 4a Recess 4b Dust-proof and drip-proof cover 6 Holding unit 8 Grinding unit 10 Support portion 12 Lifting unit 14 Guide rail 16 Moving plate 18 Ball screw 20 Pulse motor 22 Holding member 24 Spindle housing 26 Spindle 28 Wheel mount 30 Grinding wheel 32 Wheel base 34 Grinding stone 36 Frame 38 Holding surface 40, 40a, 40b, 40c Holding table 42a, 42b, 42c Porous member 44a, 44b, 44c Table frame 46a, 46b, 46c Storage recess 48 Suction source 50a, 50b, 50c Opening and closing valve 52 Suction path 54 Grinding wheel 54a, 54b, 54c Table lifting mechanism 56a, 56b, 56c Piezoelectric actuator 58a, 58b, 58c Base plate 60a, 60b, 60c Ventilation port 62a, 62b, 62c Tilt adjustment mechanism 64a, 64b, 64c Piezoelectric actuator 66a, 66b, 66c Ventilation port 68 Table adjustment mechanism 70 Piezoelectric actuator

Claims (4)

A grinding device comprising: a holding unit having a holding surface for holding a plurality of workpieces; a grinding unit in which grinding wheels are disposed for grinding the upper surfaces of the plurality of workpieces held by the holding unit; and a lifting unit for lifting and lowering the grinding unit in a direction perpendicular to the holding surface,
The holding unit includes a plurality of accommodating recesses exposed on the holding surface, a plurality of holding tables accommodated in the accommodating recesses , and a plurality of table lifting mechanisms accommodated in the respective accommodating recesses for lifting and lowering the respective holding tables in a direction perpendicular to the holding surface.
a horizontal movement unit that moves the holding unit and the grinding unit relatively in a direction parallel to the holding surface ,
the holding unit is capable of holding a plurality of the workpieces placed on the upper surface of each of the holding tables;
a horizontal movement unit that operates the grinding wheels to creep feed grind the upper surfaces of the workpieces held on the respective holding tables from one end to the other end, thereby enabling each of the workpieces, the upper surfaces of which are not uniform in height before creep feed grinding, to be brought to the respective finishing thicknesses. 2. The grinding apparatus according to claim 1 , wherein the holding unit further comprises an inclination adjustment mechanism for adjusting the inclination of the upper surface of the holding table relative to the grinding wheel. the workpiece has a first layer and a second layer overlying the first layer;
3. The grinding device according to claim 1, wherein each of the holding tables holds the workpiece from the first layer side, the height of each of the holding tables is adjusted so that when the plurality of workpieces are creep feed ground with the grinding wheel , the thickness of the second layer of all of the workpieces is uniform, and the plurality of workpieces are creep feed ground with the grinding wheel. 4. The grinding device according to claim 1 , wherein the grinding unit is capable of creep feed grinding two or more of the plurality of workpieces held by the holding unit simultaneously with the grinding wheel.