Processing equipment

Abstract

To provide a processing device that reduces an influence of rough grinding, performs fine grinding, and accurately processes a workpiece.SOLUTION: A processing device 1 comprises: an index table 2 including a plurality of chucks 22 that adsorbs and holds a workpiece W, and conveying the workpiece W to a rough grinding stage S2 provided with rough grinding means that rough grinds the workpiece W, a middle grinding stage S3 provided with middle grinding means that middle grinds the workpiece W, and a fine grinding stage S4 provided with fine grinding means that fine grinds the workpiece W, in this order; a first column 31 provided across above the index table 2 and installed with one of the rough grinding means or the fine grinding means; and a second column 32 provided across above the index table 2, provided independently from the first column 31, installed with the middle grinding means, and installed with the other of the rough grinding means and the fine grinding means in parallel to the middle grinding means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a processing device that performs rough grinding, medium grinding, and fine grinding on a workpiece in sequence. [Background technology]

[0002] 2. Description of the Related Art In the field of semiconductor manufacturing, back grinding is performed to grind the back surface of a semiconductor wafer such as a silicon wafer (hereinafter referred to as a "workpiece") to form a thin film.

[0003] As a processing device for grinding the back surface of a workpiece, Patent Document 1 discloses an in-feed grinding device that sequentially performs rough grinding and fine grinding on the workpiece while suppressing axial tilt of the grinding wheel during grinding by arranging a rough grinding spindle and a fine grinding spindle on a column that is installed across an index table. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 094646 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the processing device described in Patent Document 1 as mentioned above, the rough grinding spindle and the fine grinding spindle are arranged in the same column, and vibrations generated during rough grinding, in which a relatively large amount of removal is required, are transmitted to the fine grinding spindle via the column, causing the fine grinding wheel to cut into the workpiece unnecessarily, or the column or base may be deformed by the load during rough grinding, causing the fine grinding wheel to cut into the workpiece at an unintended angle, which could result in the workpiece not being machined with high precision.

[0006] Therefore, a technical problem to be solved arises: how to reduce the effects of rough grinding and perform fine grinding to accurately machine the workpiece. An object of the present invention is to solve this problem. [Means for solving the problem]

[0007] The present invention has been proposed to achieve the above-mentioned object, and provides a processing device that performs rough grinding, medium grinding, and fine grinding on a workpiece in sequence, the processing device comprising: a plurality of chucks that suction-hold the workpiece, an index table that transports the workpiece in the order of a rough grinding stage provided with a rough grinding means for rough grinding the workpiece, a medium grinding stage provided with a medium grinding means for medium grinding the workpiece, and a fine grinding stage provided with a fine grinding means for fine grinding the workpiece; a first column that is arranged to straddle above the index table and in which one of the rough grinding means or the fine grinding means is installed; and a second column that straddles above the index table and is arranged independently of the first column, in which the medium grinding means is installed and in which the other of the rough grinding means or the fine grinding means is installed alongside the medium grinding means. [Effects of the Invention]

[0008] In the present invention, a first column and a second column are provided independently of each other, and a rough grinding means that causes a large displacement in the processing device due to reaction during processing is provided on one of the first column or the second column, and a fine grinding means that has a large effect on the finished shape of the workpiece is provided on the other of the first column or the second column, thereby enabling the workpiece to be processed with high precision. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a processing device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a plan view showing a processing device with some components omitted. [Figure 3] FIG. [Figure 4] FIG. 4 is a longitudinal cross-sectional view of the processing device at the intermediate grinding stage. [Figure 5] FIG. 10 is a plan view showing a processing device in an independent precision grinding layout, with some components omitted. [Figure 6] FIG. 10 is a contour diagram showing displacements occurring in a machining device with a rough grinding independent layout. [Figure 7] 10 is a contour diagram showing displacements occurring in an index table and a base in a processing apparatus with an independent rough grinding layout. [Figure 8] FIG. 10 is a contour diagram showing displacements occurring in a machining device with a precision grinding independent layout. [Figure 9] 10 is a contour diagram showing displacements occurring in an index table and a base in a processing device with an independent precision grinding layout. [Figure 10] FIG. 10 is a diagram showing the results of measuring the shape of a workpiece machined by a machining device with an independent rough grinding layout. [Figure 11] FIG. 10 is a diagram showing the results of measuring the shape of a workpiece machined by a machining device with an independent precision grinding layout. [Figure 12] 10 is a graph showing vibration data of a medium grinding means in a processing apparatus with an independent rough grinding layout. [Figure 13] 10 is a graph showing vibration data of a fine grinding means in a processing apparatus with an independent rough grinding layout. [Figure 14] 10 is a graph showing vibration data of a medium grinding means in a processing apparatus with an independent fine grinding layout. [Figure 15] 10 is a graph showing vibration data of a precision grinding means in a processing apparatus with an independent precision grinding layout. DETAILED DESCRIPTION OF THE INVENTION

[0010] A processing device 1 according to one embodiment of the present invention will be described below with reference to the drawings. In the following examples, when the number, numerical value, amount, range, etc. of components are mentioned, they are not limited to the specific number, and may be more or less than the specific number, unless otherwise specified or when they are clearly limited to a specific number in principle.

[0011] Furthermore, when referring to the shape or positional relationship of components, etc., it includes things that are substantially similar or approximate to those shapes, etc., unless otherwise specified or when it is clearly considered otherwise in principle.

[0012] In addition, the drawings may exaggerate characteristic parts to make the features easier to understand, and the dimensional proportions of the components may not be the same as in reality. In addition, in cross-sectional views, hatching of some components may be omitted to make the cross-sectional structure of the components easier to understand.

[0013] Fig. 1 is a perspective view showing the configuration of the processing device 1. Fig. 2 is a partially omitted plan view of the processing device 1. Fig. 3 is a plan view showing the index table 2.

[0014] The processing device 1 is capable of grinding multiple workpieces W in parallel, using three grinding wheels to grind the backside of the workpiece W in stages to form the desired shape. The workpiece W to be ground using the processing device 1 is preferably a silicon wafer, silicon carbide wafer, or other workpiece exhibiting high hardness and brittleness, but is not limited to these. The workpiece W may also be a two-layer workpiece, such as a wafer with a soft protective tape attached or a wafer supported on a hard support substrate.

[0015] The processing device 1 includes an index table 2, a main unit 3 arranged above the index table 2, and a base 4 on which the index table 2 and the main unit 3 are placed.

[0016] The index table 2 has four chucks 22 arranged concentrically around a rotation axis 21 at 90-degree intervals. The index table 2 rotates around the rotation axis 21 to transport the chucks 22 between the loading / unloading stage S1, the rough grinding stage S2, the medium grinding stage S3, and the fine grinding stage S4. The index table 2 can rotate either clockwise or counterclockwise around the rotation axis 21 when viewed from above. Each chuck 22 is connected to a vacuum source (not shown), and a workpiece W placed on the chuck 22 is sucked and held by negative pressure. The chucks 22 are connected to a motor (not shown) and can rotate.

[0017] A partition plate 23 is disposed between the chucks 22, and the partition plate 23 prevents the cooling water used in each stage from splashing onto the adjacent stage.

[0018] The main unit 3 includes an arch-shaped first column 31 and a second column 32, each of which is arranged to straddle the index table 2. The first column 31 and the second column 32 are formed to have a larger diameter and higher rigidity than the index table 2. The first column 31 and the second column 32 are provided independently, which prevents vibrations occurring in one column from affecting the other.

[0019] The first column 31 includes a base 33 formed in a substantially E-shape in plan view, and two support pillars 34 erected from the base 4 and connected to the ends of the base 33, respectively.

[0020] The base 33 is installed above the loading / unloading stage S1 and the rough grinding stage S2. Two grooves 35a, 35b are formed in the vertical direction so as to open to the rear surface 33a of the base 33. The grooves 35a, 35b are provided so as to accommodate the chuck 22 in plan view, and are located above the loading / unloading stage S1 and the rough grinding stage S2, respectively.

[0021] The loading / unloading stage S1 is a stage for transporting the workpiece W onto the chuck 22 by a transport device or the like (not shown) and for removing the workpiece W from the chuck 22. The loading / unloading stage S1 is exposed to the side of the first column 31, and when transporting the workpiece W to or from the chuck 22, the transport device or the like can smoothly access the chuck 22 without interfering with the first column 31.

[0022] The rough grinding stage S2 is a stage for roughly grinding the workpiece W. Rough grinding means 5 is provided in the groove 35b.

[0023] The rough grinding means 5 includes a rough grinding wheel 51, a first spindle 52 having the rough grinding wheel 51 attached to its lower end, and a first spindle feed mechanism 53 for vertically raising and lowering the first spindle 52. Three linear guides are provided on the rear surface 33a of the first column 31 and the innermost surface 35c of the groove 35b, serving as first guides for vertically slidably supporting the first spindle 52. The first guides are front guides 54a, which are respectively located on both sides of the rear surface 33a across the groove 35b, and a rear guide 54b, which is located on the innermost surface 35c of the groove 35b. The rough grinding means 5 also includes a first constant-pressure cylinder 55.

[0024] The second column 32 includes a base portion 36 formed in a substantially E-shape in plan view, and two support pillars 37 erected from the base 4 and connected to the ends of the base portion 36, respectively.

[0025] The base 36 is installed above the medium grinding stage S3 and the fine grinding stage S4. Two grooves 38a, 38b are formed in the vertical direction and open to the front surface 36a of the base 36. The grooves 38a, 38b are provided so as to accommodate the chuck 22 when viewed from above, and are located above the medium grinding stage S3 and the fine grinding stage S4, respectively.

[0026] The medium grinding stage S3 is a stage for medium grinding the workpiece W. Medium grinding means 6 is provided in the groove 38a.

[0027] The medium grinding means 6 includes a medium grinding wheel 61, a second spindle 62 having the medium grinding wheel 61 attached to its lower end, and a second spindle feed mechanism 63 for vertically raising and lowering the second spindle 62. Three linear guides are provided on the front surface 36a of the second column 32 and the rear surface 38c of the groove 38a to support the second spindle 62 so that it can slide vertically. The second guides are front guides 64a, which are located on both sides of the front surface 36a across the groove 38a, and a rear guide 64b, which is located on the rear surface 38c of the groove 38a. The medium grinding means 6 also includes a second constant-pressure cylinder 65.

[0028] The precision grinding stage S4 is a stage for precision grinding the workpiece W. Precision grinding means 7 is provided in the groove 38b.

[0029] The precision grinding means 7 includes a precision grinding wheel 71, a third spindle 72 having the precision grinding wheel 71 attached to its lower end, and a third spindle feed mechanism 73 for vertically raising and lowering the third spindle 72. Three linear guides are provided on the front surface 36a of the second column 32 and the rear surface 38d of the groove 38b, serving as third guides for vertically slidably supporting the third spindle 72. The third guides are front guides 74a, which are located on both sides of the front surface 36a across the groove 38b, and a rear guide 74b, which is located on the rear surface 38d of the groove 38b. The precision grinding means 7 also includes a third constant-pressure cylinder 75.

[0030] The rough grinding stage S2 and the fine grinding stage S4 can be switched in position by replacing the rough grinding wheel 51 with the fine grinding wheel 71. Whether the rough grinding wheel 51 or the fine grinding wheel 71 is disposed in the first column 31 and the other in the second column 32 is determined according to the configuration of the workpiece W.

[0031] The operation of the processing device 1 is controlled by a control unit (not shown). The control unit controls each of the components that make up the processing device 1. The control unit is composed of, for example, a CPU, a memory, etc. The functions of the control unit may be realized by control using software, or may be realized by operation using hardware.

[0032] In this way, the processing device 1 sends the workpiece W, which is suction-held by the chuck 22 of the carry-in / carry-out stage S1, in the order of rough grinding stage S2, medium grinding stage S3, and fine grinding stage S4 while it is placed on the same chuck 22. Furthermore, the chuck 22 that suction-holds the workpiece W can be made more rigid than other workpiece holding devices such as belt conveyors. As a result, the throughput of the grinding process is improved and the workpiece W can be ground with high quality.

[0033] Next, specific configurations of the rough grinding means 5, medium grinding means 6, and fine grinding means 7 will be described. Since the rough grinding means 5, medium grinding means 6, and fine grinding means 7 have almost the same configuration, the following description will focus on the medium grinding means 6 as a representative, and redundant descriptions of the rough grinding means 5 and fine grinding means 7 will be omitted. Figure 4 is a vertical cross-sectional view of the processing apparatus 1 at the medium grinding stage S3.

[0034] The medium grinding wheel 61 is configured by arranging a plurality of cup-shaped grinding wheels at the bottom end in the circumferential direction.

[0035] The second spindle 62 includes a saddle 62a having the medium grinding wheel 61 attached to its lower end, and a motor (not shown) that is provided inside the saddle 62a and rotates the medium grinding wheel 61.

[0036] The second spindle feed mechanism 63 includes a nut 63a that connects the saddle 62a to a second guide 64 located at the rear, a ball screw 63b that raises and lowers the nut 63a, and a motor 63c that rotates the ball screw 63b.

[0037] The motor 63c is driven to rotate the ball screw 63b in the forward direction, and the nut 63a descends in the feed direction D of the ball screw 63b, which is parallel to the vertical direction, thereby lowering the saddle 62a. The feed direction D of the ball screw 63b is on a straight line parallel to the vertical direction that passes through the processing point P1 where the medium grinding wheel 61 processes the workpiece W. In other words, the rotation axis O of the ball screw 63b and the processing point P1 of the medium grinding wheel 61 are arranged on approximately the same straight line in the vertical direction.

[0038] The main unit 3 is provided with an in-process gauge (not shown) that measures the thickness of the workpiece W. When the thickness of the workpiece W measured by the in-process gauge reaches a desired value, the motor 63c is driven to reversely rotate the ball screw 63b, and the saddle 62a connected to the nut 63a rises, thereby separating the workpiece W from the medium grinding wheel 61.

[0039] As shown in FIG. 1, the second constant pressure cylinders 65 are provided on both sides in the horizontal direction, with a nut 63a sandwiched between them. The second constant pressure cylinders 65 suspend the second spindle 62 and the second spindle feed mechanism 63 within the groove 38a. Specifically, the lower end of the piston rod of the second constant pressure cylinder 65 is connected to the nut 63a. By providing the second constant pressure cylinders 65 on both sides in the horizontal direction, with the second spindle feed mechanism 63 sandwiched between them, tilting of the second spindle feed mechanism 63 in the horizontal direction is restricted when the second spindle feed mechanism 63 is raised.

[0040] The second constant pressure cylinder 65 is an air cylinder employing a known configuration including a cylinder, piston, piston rod, compressor, etc. (not shown). When the thrust force acting on the medium grinding wheel 61 during grinding is transmitted to the piston rod, the second constant pressure cylinder 65 raises the piston so as to push back the compressed air filled inside the cylinder of the second constant pressure cylinder 65. The driving pressure of the second constant pressure cylinder 65 is set to a value equal to or less than the value corresponding to the thrust force acting on the medium grinding wheel 61 when the medium grinding wheel 61 cuts into the workpiece W by the critical cutting depth (Dc value).

[0041] If the medium grinding wheel 61 attempts to cut deeper than the desired grinding amount (for example, the Dc value) and the thrust force acting on the medium grinding wheel 61 becomes excessive, the second spindle 62 and the second spindle feed mechanism 63 are temporarily raised to prevent the medium grinding wheel 61 from cutting deeper than the Dc value. Since grinding is performed at a constant pressure by the weight of the medium grinding means 6, the abrasive grains of the medium grinding wheel 61 do not come into excessive contact with the workpiece W during processing, and the workpiece W is ground in a ductile mode in a so-called floating state.

[0042] The second guide 64 is, for example, a linear guide. The second guide 64 includes a front guide 64a disposed on both sides of the front surface 36a with the groove 38a in between, and a rear guide 64b disposed on the inner surface 38c of the groove 38a. A saddle 62a is directly attached to the front guide 64a. The saddle 62a is also attached to the rear guide 64b via a nut 63a.

[0043] The front guide 64a and the rear guide 64b are provided parallel to each other along the vertical direction and restrict the movement of the saddle 62a along the vertical direction. In addition, the front guide 64a and the rear guide 64b position the center of gravity of the second spindle 62 within a triangle formed by the front guide 64a and the rear guide 64b in a plan view, thereby suppressing axial tilt of the intermediate grinding means 6.

[0044] Next, a procedure for grinding the workpiece W by adjusting the arrangement of the rough grinding wheel 51 and the fine grinding wheel 71 according to the configuration of the workpiece W will be described.

[0045] The rough grinding wheel 51 and the fine grinding wheel 71 can be attached to the first column 31 or the second column 32 depending on the configuration of the workpiece W. Hereinafter, the processing apparatus 1 when the rough grinding means 5 is provided in the first column 31 will be referred to as a "rough grinding independent layout," and the processing apparatus 1 when the fine grinding means 7 is provided in the first column 31 will be referred to as a "fine grinding independent layout."

[0046] That is, as shown in FIG. 2, in the processing device 1 with an independent rough grinding layout, the rough grinding means 5 is arranged in a first column 31, the medium grinding means 6 and the fine grinding means 7 are arranged in a second column 32, and the index table 2 rotates counterclockwise on the paper surface of FIG. 2 to process the workpiece W in the order of rough grinding, medium grinding and fine grinding.

[0047] On the other hand, in the processing device 1 with an independent layout for fine grinding, as shown in FIG. 5, the fine grinding means 7 is arranged in the first column 31, and the rough grinding means 5 and medium grinding means 6 are arranged in the second column 32, and the index table 2 rotates clockwise on the paper surface of FIG. 5, processing the workpiece W in the order of rough grinding, medium grinding, and fine grinding.

[0048] Fig. 6 is a contour diagram showing the analysis results of the displacement that occurred in the machining device 1 during machining in a rough grinding independent layout. Fig. 7 is a contour diagram showing the analysis results of the displacement that occurred in the index table 2 and base 4 during machining in a rough grinding independent layout. Fig. 8 is a contour diagram showing the analysis results of the displacement that occurred in the machining device 1 during machining in a fine grinding independent layout. Fig. 9 is a contour diagram showing the analysis results of the displacement that occurred in the index table 2 and base 4 during machining in a fine grinding independent layout.

[0049] Furthermore, Figure 10 shows the thickness variation within the surface of the workpiece W after processing using a processing device 1 with an independent rough grinding layout, and Figure 11 shows the thickness variation within the surface of the workpiece W after processing using a processing device 1 with an independent fine grinding layout.

[0050] 6 and 8, it can be seen that large displacement occurs around the rough grinding means 5 in both the rough grinding independent layout and the fine grinding independent layout. Furthermore, as shown in FIG. 7, in the rough grinding independent layout, the displacement around the fine grinding means 7, which has the greatest effect on the shape of the workpiece W after machining, is approximately uniform, and as shown in FIG. 10, a workpiece W can be obtained with small thickness variations within the surface of the workpiece W. On the other hand, as shown in FIG. 9, in the fine grinding independent layout, the displacement around the fine grinding means 7 is uneven, and as shown in FIG. 11, thickness variations within the surface of the workpiece W tend to become large.

[0051] Fig. 12 shows the relationship between the amplitude and frequency of the vertical vibration of the second spindle 62 in the rough grinding independent layout, and Fig. 13 shows the relationship between the amplitude and frequency of the vertical vibration of the third spindle 72 in the rough grinding independent layout. Fig. 14 shows the relationship between the amplitude and frequency of the vertical vibration of the second spindle 62 in the fine grinding independent layout, and Fig. 15 shows the relationship between the amplitude and frequency of the vertical vibration of the third spindle 72 in the fine grinding independent layout.

[0052] The vibration of the second spindle 62 indicated by the black dot in FIG. 12 and the vibration of the third spindle 72 indicated by the black dot in FIG. 13 have the same frequency, and it can be seen that the vibration of the second spindle 62 is propagated to the third spindle 72.

[0053] Similarly, the vibration of the second spindle 62 indicated by the black dot in Fig. 14 and the vibration of the third spindle 72 indicated by the black dot in Fig. 15 have the same frequency, and it can be seen that the vibration of the second spindle 62 is propagated to the third spindle 72. However, it can be seen that the vibration propagated from the second spindle 62 to the third spindle 72 in the fine grinding independent layout is reduced compared to the rough grinding independent layout. This is because the first column 31 and the second column 32 are provided independently of each other.

[0054] As described above, taking into consideration the magnitude of displacement during grinding and the influence of vibrations propagated from the parallel medium grinding means 6, the workpiece W suitable for machining in the rough grinding independent layout or the fine grinding independent layout is as follows:

[0055] That is, when grinding a wafer (upper layer) with a soft protective tape (lower layer) attached to the backside as the workpiece W, variations in the thickness of the protective tape directly lead to variations in the thickness of the workpiece W after processing, so it is preferable to make the displacements occurring in the index table 2 and base 4 as uniform as possible to reduce variations in the thickness of the workpiece W after processing. The protective tape is made of, for example, resin. Also, "softness" means that the protective tape is flexible enough to be elastically deformed during grinding.

[0056] Therefore, when grinding a wafer with a soft protective tape attached, the rough grinding independent layout in which the displacement of the index table 2 and the base 4 is relatively small is preferable.

[0057] On the other hand, when grinding a wafer (upper layer) supported on a hard support substrate (lower layer) on the back side as the workpiece W, the wafer is processed to an extremely thin thickness of 10 μm or less, and there is a risk that the wafer will break due to the load caused by vibrations during grinding, so it is preferable to avoid damage to the workpiece W as much as possible. The support substrate is made of, for example, silicon, glass, or hard resin. Furthermore, "hardness" means that the support substrate is hard enough to support an extremely thin wafer during grinding.

[0058] Therefore, when grinding a wafer supported on a hard support substrate, it is preferable to use an independent fine grinding layout in which the vibration transmitted from the medium grinding means 6 to the fine grinding means 7 is relatively small. Similarly, even when grinding a hard wafer that does not have a support substrate, it is preferable to use an independent fine grinding layout in which the vibration transmitted from the medium grinding means 6 to the fine grinding means 7 is relatively small.

[0059] In this way, the processing apparatus 1 according to this embodiment is a processing apparatus 1 that sequentially performs rough grinding, medium grinding, and fine grinding on the workpiece W, and is equipped with a plurality of chucks 22 that suction-hold the workpiece W, an index table 2 that transports the workpiece W in the order of a rough grinding stage S2 provided with a rough grinding means 5 for rough grinding the workpiece W, a medium grinding stage S3 provided with a medium grinding means 6 for medium grinding the workpiece W, and a fine grinding stage S4 provided with a fine grinding means 7 for fine grinding the workpiece W, a first column 31 that is arranged to straddle the index table 2 and on which one of the rough grinding means 5 or the fine grinding means 7 is installed, and a second column 32 that straddles the index table 2 and is arranged independently of the first column 31, on which the medium grinding means 6 is installed, and on which the other of the rough grinding means 5 or the fine grinding means 7 is arranged alongside the medium grinding means 6.

[0060] According to this configuration, the first column 31 and the second column 32 are provided independently of each other, and the rough grinding means 5, which causes a large displacement in the processing device 1 due to the reaction force during processing, is provided on one of the first column 31 or the second column 32, and the fine grinding means 7, which has a large influence on the finished shape of the workpiece W, is provided on the other of the first column 31 or the second column 32, thereby enabling the workpiece W to be processed with high precision.

[0061] In addition, in the processing apparatus 1 according to this embodiment, when the workpiece W is a wafer with a soft protective tape attached, the rough grinding means 5 is provided in the first column 31 and the fine grinding means 7 is provided in the second column 32.

[0062] According to this configuration, the rough grinding means 5 suppresses the bias in displacement that occurs in the index table 2 and the base 4, thereby reducing variations in the thickness of the soft protective tape, and therefore the workpiece W can be processed with high precision.

[0063] In addition, in the processing apparatus 1 according to this embodiment, when the workpiece W is a wafer supported on a hard support substrate, the fine grinding means 7 is provided in the first column 31, and the rough grinding means 5 is provided in the second column 32.

[0064] According to this configuration, the vibrations generated in the rough grinding means 5 and the medium grinding means 6 are prevented from being transmitted to the fine grinding means 7, so that the extremely thin and easily broken workpiece W can be stably machined.

[0065] Moreover, the processing device 1 according to this embodiment is configured so that the index table 2 is rotatable clockwise and counterclockwise when viewed from above.

[0066] According to this configuration, the index table 2 can change its rotation direction depending on the layout of the rough grinding means 5 and the fine grinding means 7, so that the workpiece W can be transported for rough grinding, medium grinding, and fine grinding in that order.

[0067] It should be noted that the present invention can be modified in various ways without departing from the spirit of the present invention, and it goes without saying that the present invention also covers such modifications. [Explanation of symbols]

[0068] 1: Processing equipment 2: Index table 21: Rotation axis 22: Zipper 23: Partition board 3: Main unit 31: First column 32: Second column 33: Base 33a: Rear 34: Strut 35a: Groove 35b: Groove 35c: Back side 36: Base 36a:Front 37: Strut 38a: Groove 38b: Groove 38c: Back side 38d: Back side 4: Bass 5:Rough grinding means 51: Rough grinding wheel 52: First spindle 53: First spindle feed mechanism 54a: Front guide 54b: Rear guide 55: First constant pressure cylinder 6: Medium grinding means 61: Medium grinding wheel 62: Second spindle 62a: Saddle 63: Second spindle feed mechanism 63a: Nut 63b: Ball screw 63c: Motor 64a: Front guide 64b: Rear guide 65: Second constant pressure cylinder 7: Fine grinding means 71: Fine grinding wheel 72: Third spindle 73: Third spindle feed mechanism 74a: Front guide 74b: Rear guide 75: Third constant pressure cylinder D: Feed direction O: Rotation axis P1: Machining point S1: Loading / unloading stage S2: Rough grinding stage S3: Medium grinding stage S4: Precision grinding stage W: Work

Claims

1. A processing device that performs rough grinding, medium grinding, and fine grinding on a workpiece in sequence, an index table having a plurality of chucks for suction-holding the workpiece, and transporting the workpiece in the order of a rough grinding stage provided with a rough grinding means for rough grinding the workpiece, a medium grinding stage provided with a medium grinding means for medium grinding the workpiece, and a fine grinding stage provided with a fine grinding means for fine grinding the workpiece; a first column provided above the index table so as to straddle the index table, and on which one of the rough grinding means and the fine grinding means is installed; a second column that straddles the index table and is provided independently of the first column, the second column having the medium grinding means and the other of the rough grinding means and the fine grinding means disposed in parallel to the medium grinding means; A processing device comprising:

2. the rough grinding means is provided in the first column, the precision grinding means is provided on the second column, 2. The processing apparatus according to claim 1, wherein the workpiece is precision ground in a state in which the index table is displaced substantially uniformly within the precision grinding stage.

3. the precision grinding means is provided on the first column, the rough grinding means is provided in the second column, 2. The processing apparatus according to claim 1, wherein the workpiece is fine-ground in a state where vibrations transmitted from the medium grinding means to the fine grinding means are reduced.

4. 4. The processing device according to claim 1, wherein the index table is configured to be rotatable clockwise and counterclockwise when viewed from above.

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