Grinding device

Abstract

To provide a small grinding device capable of performing creep feed grinding of a plurality of work pieces to give them different thicknesses.SOLUTION: A grinding device includes: a holding unit that holds a plurality of work pieces placed on a holding surface; a grinding unit in which grinding stones for grinding respective upper surfaces of the plurality of work pieces held by the holding unit; and a raising / lowering unit that raises and lowers the grinding unit in a direction perpendicular to the holding surface. The holding unit includes: a plurality of holding tables each of which is exposed from the holding surface; and a plurality of table raising / lowering mechanisms for raising / lowering the respective holding tables in a direction perpendicular to the holding surface. Work pieces can be made to have respective finished thicknesses by activating the respective table raising / lowering mechanisms to adjust heights of the plurality of holding tables independently and grinding the plurality of work pieces held on the respective holding tables, by means of the grinding stones.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a grinding apparatus including a holding unit and a grinding wheel, which feeds a holding unit that holds a workpiece under a grinding wheel moving on an annular track, and grinds the workpiece with the grinding wheel.

Background Art

[0002] In the manufacturing process of device chips used in electronic devices such as mobile phones and personal computers, first, a plurality of chips made of materials such as semiconductors each including a device such as an IC (Integrated Circuit) or an LSI (Large-scale Integration) are prepared. Then, the plurality of chips are aligned and sealed with a mold resin to be integrated, and when the obtained package substrate is divided for each chip, individual device chips are formed.

[0003] In recent years, there has been a remarkable trend towards space saving in electronic devices on which device chips are mounted, and the demand for thinning of device chips has also increased. Therefore, in order to manufacture thin device chips, before dividing the package substrate, the package substrate is ground and thinned from the back side (mold resin side). A grinding apparatus for grinding a package substrate includes a holding unit (for example, a chuck table) capable of sucking and holding a workpiece, and a grinding wheel arranged in an annular shape.

[0004] In a grinding apparatus, for example, a grinding process called creep feed grinding is performed on a workpiece. When performing creep feed grinding, first, the height position of the bottom surface of the grinding wheel is made lower than the height of the grinding surface (upper surface) of the workpiece, and the grinding wheel is rotated and moved in a plane substantially parallel to the upper surface of the holding unit. Then, the holding unit holding the workpiece is fed under the rotating and moving grinding wheel, and grinding is performed by bringing the side surface and the bottom surface of the grinding wheel into contact with the workpiece (see Patent Document 1).

[0005] When a workpiece is ground, the grinding wheel gradually wears out and becomes thinner, and the bottom surface of the grinding wheel rises. Therefore, if left as it is, 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 ground surface of the workpiece. Thus, a method has been developed to reduce the non-uniformity in the thickness of the ground workpiece by preliminarily checking the tendency of the grinding wheel to wear and gradually lowering the grinding wheel by an amount corresponding to the amount of wear of the grinding wheel while performing creep feed grinding (see Patent Document 2).

[0006] Also, a method is known in which a plurality of workpieces are placed on a holding unit and creep feed grinding is performed so that they have different thicknesses (see Patent Document 3). In this method, the height of the grinding wheel is changed according to the finished thickness set for each of the workpieces to be ground.

[0007] To realize such grinding, it is necessary to provide a large gap between two adjacent workpieces on the holding unit. Otherwise, when grinding one workpiece, the grinding wheel may contact the other workpiece, and the other workpiece may be thinned to a thickness different from the finished thickness set for this other workpiece.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, if the holding unit is made relatively large to ensure sufficient distance between the workpieces when multiple workpieces are placed, the grinding device itself will also become large. A large grinding device has relatively high manufacturing and operating costs. Also, for example, if a grinding device installed in a clean room becomes large, it will compress the capacity of the clean room and increase the operating cost of the clean room. Therefore, miniaturization of a grinding device for performing creep feed grinding on multiple workpieces with different thicknesses is desired.

[0010] The present invention has been made in view of such problems, and an object thereof is to provide a small grinding device capable of performing creep feed grinding on multiple workpieces with different thicknesses.

Means for Solving the Problems

[0011] According to one aspect of the present invention, a holding surface having A grinding device including a holding unit that holds a plurality of workpieces, a grinding unit in which a grinding wheel for grinding the upper surfaces of the plurality of workpieces held by the holding unit is disposed, and a lifting unit that raises and lowers the grinding unit in a direction perpendicular to the holding surface, wherein the holding unit , a plurality of receiving recesses exposed on the holding surface, and respectively received in the receiving recesses A plurality of holding tables, received in each of the plurality of receiving recesses A plurality of table lifting mechanisms for lifting and lowering each of the holding tables in a direction perpendicular to the holding surface, a horizontal movement unit that relatively moves the holding unit and the grinding unit in a direction parallel to the holding surface, is provided with the holding unit can hold a plurality of the workpieces placed on the upper surfaces of the respective holding tables, By operating each of the table lifting mechanisms to according to the finish thickness of the workpiece held by each of the holding tables independently adjust the heights of the plurality of holding tables, actuate the horizontal movement unit The plurality of workpieces held on each of the holding tables by the grinding wheel creep feed grinding the upper surface from one end side to the other end side so that before creep feed grinding, the heights of the upper surface are not aligned each workpiece can be the finished to its respective finishing thickness. A grinding device is provided, which is characterized by this.

[0013] Also, preferably, the holding unit further includes an inclination adjustment mechanism for adjusting the the upper surface of the holding table inclination with respect to the grinding wheel.

[0014] Further, preferably, the workpiece has a first layer and a second layer overlapping the first layer. Each holding table holds the workpiece from the first layer side, and when grinding a plurality of the workpieces with the grinding wheel, creep feed the height of each holding table is adjusted so that the thicknesses of the second layers of all the workpieces are made uniform, and a plurality of the workpieces are creep feed ground with the grinding wheel.

[0015] Further, preferably, the grinding unit can grind two or more of the plurality of workpieces held by the holding unit simultaneously with the grinding wheel. creep feed grind.

Advantages of the Invention

[0016] In the grinding apparatus according to one aspect of the present invention, the holding unit includes a plurality of holding tables whose heights can be adjusted independently. Then, a plurality of workpieces are held by each holding table, the height of each holding table is adjusted according to the finish thickness set for each workpiece, and the upper surface of each workpiece is creep-feed ground with the grinding unit. Then, each workpiece has a thickness corresponding to the distance between each holding table and the grinding wheel. That is, in the grinding apparatus according to one aspect of the present invention, a plurality of workpieces can be ground simultaneously to different finish thicknesses.

[0017] At this time, it is not necessary to change the height of the grinding unit for each workpiece to be ground, and no problem occurs even if two or more workpieces are ground simultaneously with the grinding wheel. Therefore, it is not necessary to secure a large gap between the holding tables, and it is not necessary to increase the size of the holding unit. Therefore, it is not necessary to increase the size of the grinding apparatus.

[0018] Therefore, according to the present invention, there is provided a small-sized grinding apparatus capable of creep-feed grinding a plurality of workpieces to different thicknesses.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0020] Embodiments according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view schematically showing a grinding device 2 according to the present embodiment. The grinding device 2 according to the present embodiment can simultaneously perform creep-feed grinding on a plurality of workpieces 1. First, the workpiece 1 to be ground by the grinding device 2 will be described.

[0021] The workpiece 1 is a rectangular package substrate including a substrate made of a material such as Si (silicon), SiC (silicon carbide), or other semiconductors provided with devices such as ICs and LSIs on its surface, and a mold resin for sealing the substrate. For example, when the package substrate is ground to be thinned to a predetermined thickness and the package substrate is divided for each device, individual device chips can be obtained. However, the workpiece 1 is not limited to this.

[0022] Next, the grinding device 2 according to the present embodiment will be described. FIG. 1 is a perspective view schematically showing the grinding device 2. The grinding device 2 has a substantially rectangular parallelepiped base 4 that supports each component. On the upper surface of the base 4, a recess 4a is formed along the Y-axis direction. In the recess 4a, a holding unit 6 that can hold a plurality of workpieces 1 and is movable in the Y-axis direction, and a dust and splash cover 4b that covers the opening of the recess 4a while exposing the holding unit 6 are provided. The upper surface of the holding unit 6 serves as a holding surface 38 on which the workpiece 1 is placed.

[0023] Inside the recess 4a, a Y-axis movement mechanism (not shown) that movably supports the holding unit 6 is disposed. For example, the Y-axis movement mechanism is a ball screw type movement mechanism and has a function of moving the holding unit 6 in the Y-axis direction. Alternatively, the grinding device 2 may be provided with a Y-axis movement mechanism that moves a grinding unit 8 described later in the Y-axis direction instead of the holding unit 6.

[0024] That is, the Y-axis movement mechanism (horizontal movement unit) relatively moves the holding unit 6 and the grinding unit 8 in a direction (Y-axis direction) parallel to the holding surface 38. Details of the holding unit 6 will be described later.

[0025] 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 portion 10 is erected on the rear side of the grinding device 2, and the grinding unit 8 is supported by the support portion 10 via the lifting unit 12. On the front surface of the support portion 10, a pair of guide rails 14 along the Z-axis direction (vertical direction) are provided. A moving plate 16 is slidably attached to each guide rail 14.

[0026] On the back surface side (rear surface side) of the moving plate 16, a nut portion (not shown) is provided, and a ball screw 18 parallel to the guide rail 14 is screwed into the nut portion. A pulse motor 20 is connected to one end of the ball screw 18. When the ball screw 18 is rotated by the pulse motor 20, the moving plate 16 moves in the Z-axis direction along the guide rail 14.

[0027] On the front side of the moving plate 16, a grinding unit 8 for performing grinding on the workpiece 1 is fixed. By operating the lifting unit 12 to move the moving plate 16, the grinding unit 8 can move along the Z-axis direction. That is, the lifting unit 12 has a function of lifting the grinding unit 8 in a direction substantially perpendicular to the holding surface 38 of the holding unit 6.

[0028] 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. Inside the holding member 22, a spindle housing 24 is provided. The spindle housing 24 is supported on the bottom wall of the holding member 22 via an annular buffer member (not shown) formed of rubber or the like.

[0029] A part of the spindle 26 is rotatably accommodated in the spindle housing 24. At the upper end of the spindle 26, a rotational drive mechanism (not shown) such as a motor is connected. When the rotational drive mechanism is operated, the spindle 26 rotates. Note that the direction of the spindle 26 does not necessarily strictly follow the Z-axis direction, and the inclination angle of the spindle 26 from the Z-axis direction may be set to a predetermined value. For example, the inclination angle of the grinding unit 8 from the direction perpendicular to the holding surface 38 of the holding unit 6 is adjustable.

[0030] 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 mounted on the lower surface of the wheel mount 28.

[0031] The grinding wheel 30 has an annular wheel base 32. The wheel base 32 is formed 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 side of this wheel base 32 is connected to the lower surface side of the wheel mount 28. That is, the grinding wheel 30 is mounted on the spindle 26 via the wheel mount 28.

[0032] On the lower surface of the wheel base 32, a plurality of grinding wheels 34 are provided. Each grinding wheel 34 is formed, for example, by mixing abrasive grains such as diamond or cBN (cubic boron nitride) with a binder such as vitrified or resinoid, and sintering the mixture. When the spindle 26 is rotated to rotate the grinding wheel 30, the grinding wheel 34 rotates and moves on an annular track.

[0033] Creep feed grinding is known as a method for grinding the workpiece 1 to a predetermined thickness. In creep feed grinding, first, the height position of the bottom surface of the grinding wheel 34 is made lower than the height of the surface to be ground (upper surface) of the workpiece 1, and the grinding wheel 34 is rotated and moved in a plane substantially parallel to the holding surface 38 of the holding unit 6. Then, the holding unit 6 that holds the workpiece 1 is moved in a direction parallel to the holding surface 38 (Y-axis direction) and fed under the rotating and moving grinding wheel 34, and grinding is performed by bringing the side surface and the bottom surface of the grinding wheel 34 into contact with the workpiece 1.

[0034] Here, a method is known in which a plurality of workpieces 1 having different thicknesses are placed on the holding surface 38 of the holding unit 6, and creep feed grinding is performed so as to have different thicknesses. In this method, the height of the grinding wheel 34 is changed according to the workpiece 1 to be ground. That is, when the grinding wheel 34 overlaps the unprocessed 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 with reference to the finished thickness of the workpiece 1.

[0035] Here, while creep-feed grinding a workpiece 1 with a certain finishing thickness, if the grinding wheel 34 hits another workpiece 1 with a thicker finishing thickness, this other workpiece 1 will be overly thinned. Therefore, in order to realize the grinding of a plurality of workpieces 1 with different finishing thicknesses, it is necessary to ensure a wide gap between two adjacent workpieces 1 on the holding unit 6. This gap is, for example, sized such that the grinding wheel 34 for grinding one workpiece 1 does not hit other workpieces 1 during the process of rotating and moving along an annular orbit.

[0036] However, in the holding unit 6 that can hold a plurality of workpieces 1, when ensuring a sufficiently wide interval between the workpieces 1, it is necessary to enlarge the holding surface 38 of the holding unit 6. Enlarging the holding unit 6 will enlarge the grinding device 2 itself, and the occupied area of the grinding device 2 will increase. For example, when the grinding device 2 is placed in a clean room, it will compress the capacity of the clean room, making it difficult to install other devices. As a result, the operating efficiency of the clean room and the like will deteriorate. In addition, large grinding devices 2 incur high manufacturing and operation costs.

[0037] Therefore, miniaturization of the grinding device 2 for performing creep-feed grinding on a plurality of workpieces 1 so that they have different thicknesses is desired. Thus, the grinding device 2 according to the present embodiment has been developed as a grinding device that can perform creep-feed grinding on a plurality of workpieces 1 so that they have different thicknesses without increasing the size of the device configuration.

[0038] FIG. 2 is a perspective view schematically showing the holding unit 6 of the grinding device 2 according to the present embodiment. FIG. 3 is a cross-sectional view schematically showing the holding unit 6. In the grinding device 2 according to the present embodiment, the holding unit 6 includes a plurality of holding tables 40 exposed on the holding surface 38 respectively. In the example shown in FIG. 2 and the like, the holding unit 6 includes a first holding table 40a, a second holding table 40b, and a third holding table 40c, and can hold three workpieces 1. However, the number of holding tables 40 is not limited to this.

[0039] The holding unit 6 includes a frame 36 formed of aluminum, stainless steel, or the like that houses each component. The frame 36 has receiving recesses 46a, 46b, 46c exposed on a holding surface 38 that can house the holding tables 40a, 40b, 40c, respectively. A suction source 48 such as a pump or an ejector is connected to the frame 36 via a suction passage 52. One end of the suction passage 52 is connected to the suction source 48, and the other end is branched and connected to the bottom surface of the frame 36 and communicates with the bottom surfaces of the receiving recesses 46a, 46b, 46c.

[0040] The branched suction passage 52 is provided with opening / closing valves 50a, 50b, 50c each constituted by a solenoid valve or the like. When the opening / closing valves 50a, 50b, 50c are actuated, the supply of the negative pressure generated by the suction source 48 to each of the receiving recesses 46a, 46b, 46c and the stop of the supply can be switched.

[0041] The holding unit 6 further includes a plurality of table elevating mechanisms 54a, 54b, 54c for elevating the respective holding tables 40a, 40b, 40c in a direction (Z-axis direction) perpendicular to the holding surface 38. Furthermore, the holding unit 6 further includes a plurality of inclination adjusting mechanisms 62a, 62b, 62c for adjusting the inclination of the holding surface 38 (the upper surfaces of the respective holding tables 40a, 40b, 40c) with respect to the grinding wheel 34.

[0042] The respective table elevating mechanisms 54a, 54b, 54c are supported and housed in the frame 36 in the respective receiving recesses 46a, 46b, 46c, and the inclination adjusting mechanisms 62a, 62b, 62c are supported and housed by the table elevating mechanisms 54a, 54b, 54c. Each holding table 40a, 40b, 40c is supported by the inclination adjusting mechanisms 62a, 62b, 62c and housed in the receiving recesses 46a, 46b, 46c.

[0043] Fig. 4(A) is a perspective view schematically showing a part of the table elevating mechanisms 54a, 54b, 54c supported by the frame body 36 at the bottoms of the accommodation recesses 46a, 46b, 46c. The table elevating mechanisms 54a, 54b, 54c include piezoelectric actuators 56a, 56b, 56c provided at the centers of the bottoms.

[0044] The piezoelectric actuators 56a, 56b, 56c are electrically connected to a control unit (not shown) of the grinding device 2 and expand and contract according to an electric signal supplied from the control unit. At the upper ends of the piezoelectric actuators 56a, 56b, 56c, base plates 58a, 58b, 58c (see Fig. 4(B)) of the tilt adjustment mechanisms 62a, 62b, 62c are placed. When each piezoelectric actuator 56a, 56b, 56c is actuated, the base plates 58a, 58b, 58c move up and down.

[0045] Fig. 4(B) is a perspective view schematically showing the tilt adjustment mechanisms 62a, 62b, 62c supported by the table elevating mechanisms 54a, 54b, 54c. The tilt adjustment mechanisms 62a, 62b, 62c include three piezoelectric actuators 64a, 64b, 64c that are not arranged in a straight line on the upper surfaces of the base plates 58a, 58b, 58c. These three piezoelectric actuators 64a, 64b, 64c are electrically connected to the control unit of the grinding device 2 and expand and contract according to an electric signal supplied from the control unit.

[0046] At the upper ends of the three piezoelectric actuators 64a, 64b, 64c, holding tables 40a, 40b, 40c are respectively placed. When each piezoelectric actuator 64a, 64b, 64c is actuated and its length is independently controlled, the tilt of the holding tables 40a, 40b, 40c can be adjusted.

[0047] Fig. 3 etc. show cross-sectional views schematically showing the holding tables 40a, 40b, 40c supported by the tilt adjustment mechanisms 62a, 62b, 62c. The holding tables 40a, 40b, 40c have porous members 42a, 42b, 42c exposed on the holding surfaces 38 and table frames 44a, 44b, 44c that accommodate the porous members 42a, 42b, 42c.

[0048] Further, vent holes 66a, 66b, 66c penetrating vertically are formed in the bottom plates of the table frames 44a, 44b, 44c. Also, vent holes 60a, 60b, 60c penetrating vertically are formed in the base plates 58a, 58b, 58c. There is no limitation on the positions of the vent holes 66a, 66b, 66c and the vent holes 60a, 60b, 60c.

[0049] Then, as shown in FIG. 5, when the workpieces 1a, 1b, 1c are placed on the respective holding tables 40a, 40b, 40c and the suction source 48 is operated, a negative pressure can be applied to the workpieces 1a, 1b, 1c through the vent holes 60a, 60b, 60c and the vent holes 66a, 66b, 66c. That is, the workpieces 1a, 1b, 1c can be sucked and held by the respective holding tables 40a, 40b, 40c of the holding unit 6.

[0050] In the grinding apparatus 2 according to the present embodiment, the respective table elevating mechanisms 54a, 54b, 54c can be operated to independently adjust the heights of the plurality of holding tables 40a, 40b, 40c. FIGS. 2 and 5 schematically show a holding unit 6 in which the heights of the holding tables 40a, 40b, 40c are adjusted independently of each other.

[0051] Next, a method for simultaneously grinding a plurality of workpieces 1a, 1b, 1c having different finish thicknesses in the grinding apparatus 2 according to the present embodiment will be described with reference to FIGS. 5 and 6. Here, each of the workpieces 1a, 1b, 1c has, for example, a first layer 3a, 3b, 3c and a second layer 5a, 5b, 5c overlapping the first layer 3a, 3b, 3c. For example, the first layer 3a, 3b, 3c is a wiring board, and the second layer 5a, 5b, 5c is a semiconductor chip. However, the types of the respective workpieces 1a, 1b, 1c and the number of layers provided are not limited to this.

[0052] These layers have thickness variations. In this description, creep feed grinding is performed so that the thicknesses of the second layers 5a, 5b, 5c of all the workpieces 1a, 1b, 1c are made uniform when the workpieces 1a, 1b, 1c are ground.

[0053] First, before loading each workpiece 1a, 1b, 1c into the grinding device 2, measure the thickness of each layer of each workpiece 1a, 1b, 1c with a thickness measuring device. Next, load each workpiece 1a, 1b, 1c into the holding unit 6 and place them on the respective holding tables 40a, 40b, 40c. Then, activate the suction source 48 and hold the workpieces 1a, 1b, 1c from the first layer 3a, 3b, 3c side with the respective holding tables 40a, 40b, 40c.

[0054] Then, activate the table elevating mechanisms 54a, 54b, 54c to adjust the height of the respective holding tables 40a, 40b, 40c. For example, when grinding a plurality of workpieces 1a, 1b, 1c with the grinding wheel 34, the height of each holding table 40a, 40b, 40c is adjusted so that the thicknesses of the second layers 5a, 5b, 5c of all the workpieces 1a, 1b, 1c are uniform.

[0055] Also, when there are thickness non-uniformities in the first layer 3a, 3b, 3c or the second layer 5a, 5b, 5c of the workpieces 1a, 1b, 1c respectively, the inclination of the workpieces 1a, 1b, 1c may be adjusted so as to reduce the influence on the processing result due to this non-uniformity. At this time, a plurality of piezoelectric actuators 64a, 64b, 64c constituting the inclination adjustment mechanisms 62a, 62b, 62c are independently activated to adjust the inclination of the holding tables 40a, 40b, 40c.

[0056] FIG. 5 schematically shows the holding tables 40a, 40b, 40c whose heights and the like are adjusted. At this time, operate the elevating unit 12 so that the lowermost end of the grinding wheel 54 is positioned at a height position 9 that is higher by the finish thickness 7 of the second layer 5a, 5b, 5c from the lower end of the second layer 5a, 5b, 5c. Here, in each workpiece 1a, 1b, 1c, the finish thickness changes by the amount of the difference in the thickness of the first layer 3a, 3b, 3c.

[0057] Furthermore, adjust the inclination of the spindle 26 and tilt the spindle 26 at a predetermined angle from the direction (Z-axis direction) perpendicular to the holding surface 38 of the holding unit 6. When the spindle 26 is tilted, the annular orbit of the grinding wheel 34 that rotates and moves when the spindle 26 is rotated is tilted. In this case, the grinding wheel 34 grinds the workpiece 1 when passing through a relatively low position of the annular orbit, and it becomes less likely to contact the workpiece 1 when passing through a relatively high position of the annular orbit. Thereby, the flatness of the ground surface of the workpiece 1 may be improved.

[0058] Alternatively, adjust the inclination of the spindle 26 and align the direction of the spindle 26 in the direction perpendicular to the holding surface 38 of the holding unit 6 (Z-axis direction). In this case, the annular orbit of the grinding wheel 34 that rotates and moves 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.

[0059] Next, as shown in FIG. 6, rotate the spindle 26 to rotate and move the grinding wheel 34 on the annular orbit, and operate the Y-axis movement mechanism (horizontal movement unit) to move the holding unit 6 from the initial position and pass under the grinding wheel 34. FIG. 6 schematically shows a state in which each workpiece 1a, 1b, 1c has been ground by the grinding wheel 34 to the respective finish thicknesses and the holding unit 6 has been returned to the initial position.

[0060] More specifically, first, the rotating and moving grinding wheel 34 contacts the second layer 5c of the third workpiece 1c and the third workpiece 1c is ground. Thereafter, the grinding wheel 34 contacts the second layer 5b of the second workpiece 1b and the second workpiece 1b is ground. At this time, there is no problem even if the grinding wheel 34 contacts the third workpiece 1c when the rotating and moving grinding wheel 34 passes over the third workpiece 1c.

[0061] Subsequently, the grinding wheel 34 contacts the second layer 5a of the first workpiece 1a and the first workpiece 1a is ground. At this time, even if the grinding wheel 34 contacts the second workpiece 1b when passing over the second workpiece 1b, there is no problem. In this way, the upper surfaces of the workpieces 1a, 1b, and 1c are creep-feed ground by the grinding wheel 34 from one end side toward the other end side.

[0062] That is, in the grinding apparatus 2 according to the present embodiment, by grinding the plurality of workpieces 1a, 1b, and 1c held on the respective holding tables 40a, 40b, and 40c with the grinding wheel 34, each of the workpieces 1a, 1b, and 1c is ground to its respective finish thickness. At this time, the grinding unit 8 can grind two or more of the plurality of workpieces 1a, 1b, and 1c held by the holding unit 6 simultaneously with the grinding wheel 34.

[0063] As described above, when using the grinding apparatus 2 according to the present embodiment, when creep-feed grinding a plurality of workpieces 1 having different finish thicknesses simultaneously, it is not necessary to change the height of the grinding unit 8 for each workpiece 1. Further, since there is no problem even if the grinding wheel 34 for grinding a certain workpiece 1 contacts another adjacent workpiece 1, it is not necessary to secure a large gap between the respective holding tables 40a, 40b, and 40c, and it is not necessary to increase the size of the holding unit 6. Therefore, it is not necessary to increase the size of the grinding apparatus 2.

[0064] Note that the present invention is not limited to the description of the above embodiment, and various modifications can be made and implemented. For example, in the above embodiment, the case where the holding unit 6 includes the table elevating mechanisms 54a, 54b, and 54c for adjusting the heights of the respective holding tables 40a, 40b, and 40c and the inclination adjusting mechanisms 62a, 62b, and 62c for adjusting the inclination has been described. However, the grinding apparatus 2 according to one aspect of the present invention is not limited to this.

[0065] For example, the grinding device 2 may include a table adjustment mechanism 68 that combines the functions of a table lifting mechanism and an inclination adjustment mechanism. FIG. 4(C) is a perspective view schematically showing the table adjustment mechanism 68. The table adjustment mechanism 68 is constituted by, for example, six piezoelectric actuators 70 as shown in FIG. 4(C). The table adjustment mechanism 68 can simultaneously adjust the height and inclination of the holding tables 40a, 40b, and 40c by independently operating and expanding / contracting the six piezoelectric actuators 70.

[0066] The structure, method, etc. according to the above embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

Explanation of Reference Numerals

[0067] 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 and splash cover 6 Holding unit 8 Grinding unit 10 Support part 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 Accommodation recess 48 Suction source 50a, 50b, 50c On-off 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 Vent hole 62a, 62b, 62c Tilt adjustment mechanism 64a, 64b, 64c Piezoelectric actuator 66a, 66b, 66c Vent hole 68 Table adjustment mechanism 70 Piezoelectric actuator

Claims

1. A grinding device comprising: a holding unit having a holding surface for holding a plurality of workpieces; a grinding unit in which a grinding wheel for grinding the upper surfaces of the plurality of workpieces held by the holding unit is disposed; and a lifting unit for lifting and lowering the grinding unit in a direction perpendicular to the holding surface, wherein the holding unit includes a plurality of accommodation recesses exposed on the holding surface, a plurality of holding tables respectively accommodated in the accommodation recesses, and a plurality of table lifting mechanisms respectively accommodated in the plurality of accommodation recesses for lifting and lowering the respective holding tables in a direction perpendicular to the holding surface, the holding unit and the grinding unit are provided with a horizontal movement unit for relatively moving the holding unit and the grinding unit in a direction parallel to the holding surface, the holding unit can hold the plurality of workpieces placed on the upper surfaces of the respective holding tables, each of the table lifting mechanisms is operated to independently adjust the height of the plurality of holding tables according to the finish thickness of the workpiece held by each holding table, and the horizontal movement unit is operated to perform creep feed grinding on the upper surfaces of the plurality of workpieces held by the respective holding tables from one end side to the other end side with the grinding wheel, so that each workpiece whose upper surface height is not aligned before creep feed grinding can be made to the respective finish thickness. The grinding device is characterized by this.

2. The grinding device according to claim 1, wherein the holding unit further includes an inclination adjustment mechanism for adjusting the inclination of the upper surface of the holding table with respect to the grinding wheel.

3. The workpiece has a first layer and a second layer overlapping the first layer, each holding table holds the workpiece from the first layer side, the height of each holding table is adjusted so that the thickness of the second layer of all the workpieces is aligned when the plurality of workpieces are creep feed ground with the grinding wheel, and the plurality of workpieces are creep feed ground with the grinding wheel. The grinding device according to claim 1 or claim 2 is characterized by this.

4. The grinding device according to any one of claims 1 to 3, wherein the grinding unit can perform creep feed grinding on two or more of the plurality of workpieces held by the holding unit at the same time with the grinding wheel.

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