Processing system

Abstract

To provide a machining system that is able to accurately machine a workpiece.SOLUTION: A machining system 1 includes: a tilt device capable of tilting a rotation axis 3a of a chuck 3 that holds a workpiece W; a film thickness measurement device 7 that measures a film thickness of the finely ground workpiece W; and a control device 8 that calculates a shape of the finely ground workpiece W, based on a measurement value of the film thickness measurement device 7, calculates a tilt angle of the tilt device so as to reduce the difference between a maximum thickness and a minimum thickness of the finely ground workpiece W, and tilts the chuck 3 by the tilt angle. The finely ground workpiece W having a film thickness obtained by adding a predetermined offset thickness to a final target thickness is re-machined in the following order, rough grinding, intermediate grinding, and fine grounding, while the chuck 3 is kept inclined by the inclination angle.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a processing system for thinly processing a workpiece.

Background Art

[0002] In the field of semiconductor manufacturing, a grinding apparatus is known that presses the grinding surface of a rotating grinding wheel against a semiconductor wafer (hereinafter referred to as "workpiece") such as a silicon wafer to thinly and flatly grind the workpiece.

[0003] Patent Document 1 discloses an apparatus that processes a workpiece in the order of rough grinding and finish grinding, cleans the protective tape and the back surface of the workpiece, and then measures the thickness of the workpiece using a capacitance sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in order to process a workpiece with high accuracy, the finish grinding of the workpiece may be temporarily stopped, the thickness of the workpiece may be measured, and based on the measurement result, the same workpiece may be finish ground again. However, recently, the grain size of the grinding wheel has become finer, and even if the finish grinding is restarted after the thickness measurement, the dressing of the grinding wheel is insufficient, the cutting ability of the grinding wheel deteriorates, and the shape of the workpiece after regrinding may become unstable or surface burning may occur.

[0006] Therefore, a technical problem to be solved in order to process a workpiece with high accuracy occurs, and an object of the present invention is to solve this problem.

Means for Solving the Problems

[0007] To achieve the above objective, the processing system according to the present invention is a processing system that processes a workpiece in the order of pre-grinding and fine grinding, comprising: a tilt device that can tilt the rotation axis of a chuck that holds the workpiece; a measuring device that measures the film thickness of the workpiece after fine grinding; a control device that calculates the shape of the workpiece after fine grinding based on the measurement value of the measuring device, calculates the tilt angle of the tilt device so that the difference between the maximum thickness and the minimum thickness of the workpiece after fine grinding is small, and tilts the chuck by the tilt angle, and reprocesses the workpiece after fine grinding, which has a film thickness of the final target thickness plus a predetermined offset thickness, in the order of pre-grinding and fine grinding with the chuck tilted by the tilt angle.

[0008] With this configuration, the measuring device measures the film thickness of the workpiece after the first stage of processing, and the control device calculates the tilt angle of the chuck's rotation axis that allows the workpiece to be processed to be nearly flat based on the shape of the workpiece after the first stage of processing. By tilting the chuck's rotation axis by this angle and performing pre-grinding and fine grinding again on the workpiece, even if the fine grinding wheel is fine, the fine grinding wheel is sharpened by pre-grinding and its cutting ability is maintained, thus enabling efficient and highly accurate processing of the workpiece. [Effects of the Invention]

[0009] This invention enables high-precision machining of workpieces. [Brief explanation of the drawing]

[0010] [Figure 1] A plan view showing a processing system according to one embodiment of the present invention. [Figure 2] A schematic diagram showing the positional relationship of measurement points of a measuring device on a workpiece. [Figure 3] A schematic diagram showing the first stage of machining on a workpiece. [Figure 4] A schematic diagram showing the second stage of machining on a workpiece. [Figure 5] A schematic diagram showing the machining process on the second workpiece. [Modes for carrying out the invention]

[0011] One embodiment of the present invention will be described with reference to the drawings. In the following, when referring to the number, numerical values, quantities, ranges, etc., of components, unless specifically indicated or clearly limited to a particular number in principle, the number is not limited to that particular number and may be greater than or less than that number.

[0012] Furthermore, when referring to the shape, positional relationship, etc. of constituent elements, unless otherwise explicitly stated or it is clearly considered not to be so in principle, this includes things that are substantially similar or alike to those shapes, etc.

[0013] Furthermore, drawings may exaggerate features by enlarging characteristic parts to make them easier to understand, and the dimensional ratios of components may not be the same as in reality. Also, in cross-sectional drawings, hatching of some components may be omitted to make the cross-sectional structure of the components easier to understand.

[0014] Figure 1 is a plan view showing the basic configuration of the processing system 1. The processing system 1 performs multiple grinding processes on the workpiece W in sequence. The processing system 1 may also perform only grinding or polishing.

[0015] The machining system 1 is equipped with four stages: a platform stage ST1, a rough grinding stage ST2, a medium grinding stage ST3, and a fine grinding stage ST4. The number of stages (pre-grinding stages) that sequentially process the workpiece W upstream of the fine grinding stage ST4 is not limited to two, namely the rough grinding stage ST2 and the medium grinding stage ST3, but may be one or more.

[0016] The machining system 1 includes an index table 2 that can rotate clockwise around the plane of FIG. 1, and four chucks 3 arranged at equal intervals on concentric circles around the rotation axis 2a of the index table 2. When the index table 2 rotates stepwise by 90° each time, the chuck 3 can move in the order of the platform stage ST1, rough grinding stage ST2, semi-finishing grinding stage ST3, and finish grinding stage ST4.

[0017] The chuck 3 has an absorber 32 made of a porous material such as alumina embedded in the upper surface of the rotary table 31. The chuck 3 has a pipeline (not shown) that passes through the inside and extends to the surface. The pipeline is connected to a vacuum source, a compressed air source, or a water supply source via a rotary joint (not shown). When the vacuum source is activated, the workpiece W placed on the chuck 3 is adsorbed and held by the chuck 3. Also, when the compressed air source or the water supply source is activated, the adsorption between the workpiece W and the chuck 3 is released.

[0018] The rotary table 31 is connected to a chuck spindle (not shown). The chuck spindle is configured to be rotatably driven around a rotation axis perpendicular to the rotary table 31. Note that the chuck 3 may be provided with a tilt mechanism (not shown) of a known configuration that can tilt the rotary table 31.

[0019] At the platform stage ST1, the workpiece W before grinding is conveyed onto the chuck 3 by a conveying arm (not shown). Positioning is performed in advance on the workpiece W so that its orientation coincides with a predetermined direction. Also, the workpiece W after grinding is carried out from the chuck 3 by the conveying arm to a cleaning device (not shown).

[0020] The rough grinding stage ST2 is provided with a rough grinding device 4. The rough grinding device 4 includes a rough grinding wheel (not shown), a first spindle 41 to which the rough grinding wheel is attached at the lower end and that supports the rough grinding wheel rotatably, and a first spindle feed mechanism 42 that raises and lowers the first spindle 41 in the vertical direction.

[0021] For rough grinding, a cup-shaped grinding wheel of, for example, #8000 is used. The first spindle feed mechanism 42 includes two linear guides 43 that guide the moving direction of the first spindle 41, and a ball screw slider mechanism 44 that raises and lowers the first spindle 41.

[0022] In addition, the rough grinding device 4 is provided with a first contact type thickness measuring device 45. The first contact type thickness measuring device 45 includes a pair of detection arms 46 and 47 provided with contacts at their tips.

[0023] During rough grinding, the contact of the detection arm 46 abuts against the upper surface of the workpiece W, and the contact of the detection arm 47 abuts against the upper surface of the chuck 3. Thus, the thickness of the workpiece W can be measured from the difference in height detected by each contact of the detection arms 46 and 47. Note that the thickness of the workpiece W measured by the first contact type thickness measuring device 45 includes the thickness of devices formed on one surface of the workpiece W, protective tapes attached to one surface, and the like.

[0024] The intermediate grinding stage ST3 is provided with an intermediate grinding device 5. The intermediate grinding device 5 includes an intermediate grinding wheel (not shown), a second spindle 51 to which the intermediate grinding wheel is attached at the lower end and which rotatably supports the intermediate grinding wheel, and a second spindle feed mechanism 52 that raises and lowers the second spindle 51 in the vertical direction.

[0025] For the intermediate grinding wheel, a cup-shaped grinding wheel of, for example, #8000 is used. The second spindle feed mechanism 52 includes two linear guides 53 that guide the moving direction of the second spindle 51, and a ball screw slider mechanism 54 that raises and lowers the second spindle 51.

[0026] In addition, the intermediate grinding device 5 is provided with a second contact type thickness measuring device 55. The second contact type thickness measuring device 55 includes a pair of detection arms 56 and 57 provided with contacts at their tips.

[0027] During the intermediate grinding process, the contact of the detection arm 56 comes into contact with the upper surface of the workpiece W, and the contact of the detection arm 57 comes into contact with the upper surface of the chuck 3. The thickness of the workpiece W can be measured from the difference in height detected by the contacts of the detection arms 56 and 57. The thickness of the workpiece W measured by the second contact-type thickness measuring device 55 includes the thickness of devices formed on one side of the workpiece W and protective tape attached to the back side.

[0028] The precision grinding stage ST4 is equipped with a precision grinding device 6. The precision grinding device 6 comprises a precision grinding wheel 61, a third spindle 62 to which the precision grinding wheel 61 is attached at its lower end and which rotatably supports the precision grinding wheel 61, and a third spindle feed mechanism (not shown) that raises and lowers the third spindle 62 in the vertical direction.

[0029] The precision grinding wheel 61 is, for example, a cup-shaped grinding wheel with a grit of #8000. The precision grinding stage ST4 is also equipped with a non-contact thickness measuring device 63, which will be described later. The non-contact thickness measuring device 63 measures the thickness (film thickness) of the workpiece W during precision grinding.

[0030] The processing system 1 is equipped with a film thickness measuring device 7. The film thickness measuring device 7 measures the thickness (film thickness) of the workpiece W in a non-contact manner. Note that the film thickness of the workpiece W measured by the film thickness measuring device 7 does not include the thickness of devices formed on one surface of the workpiece W or protective tape attached to one surface. The film thickness measuring device 7 is, for example, a spectral interference type film thickness measuring instrument.

[0031] The film thickness measuring device 7 is fixed to a frame 1a installed within the processing system 1 and is positioned above the index table 2. The measurement point where the film thickness measuring device 7 measures the film thickness of the workpiece W is set on the rotational trajectory O of the central axis of the chuck 3 when viewed from above.

[0032] Figure 2 is a schematic diagram showing the positional relationship of the measurement points of the film thickness measuring device 7 on the workpiece W. Figure 2 illustrates the positional relationship of the measurement points of the film thickness measuring device 7 when the rotation speed of the index table 2 is set to 20 deg / s, the rotation speed of the chuck 3 is set to 400 rpm, and the sampling period of the film thickness measuring device 7 is set to 4 msec. Since the workpiece W rotates and passes directly beneath the film thickness measuring device 7, the trajectory of the measurement points of the film thickness measuring device 7 extends across the entire surface of the workpiece W, including its center. The trajectory of the measurement points of the film thickness measuring device 7 can be appropriately changed by adjusting the rotation speed of the index table 2, the rotation speed of the chuck 3, and the sampling period of the film thickness measuring device 7.

[0033] The film thickness measuring devices 7 are provided one each on the upstream and downstream sides of the precision grinding stage ST4 in the rotation direction of the index table 2. This is because, due to the rotation mechanism of the index table 2, when the processed workpiece W is transferred from the precision grinding stage ST4 to the platform stage ST1, the index table 2 may rotate clockwise or counterclockwise on the plane of Figure 1. To accommodate each rotation direction of the index table 2, one film thickness measuring device 7 is provided on the upstream and downstream sides of the precision grinding stage ST4.

[0034] The operation of the machining system 1 is controlled by the control device 8. The control device 8 controls each of the components that make up the machining system 1. The control device 8 is composed of, for example, a CPU, memory, etc. The functions of the control device 8 may be realized by control using software or by operation using hardware.

[0035] Next, we will explain the procedure for sequentially machining two workpieces W using the same chuck. Hereafter, the two workpieces W will be distinguished by the designations W1 and W2.

[0036] <First workpiece (first stage of processing)> On the platform stage ST1, the workpiece W1 is placed on the chuck 3. When the vacuum source is activated, negative pressure is supplied between the workpiece W1 and the chuck 3, causing the workpiece W1 to be held in place by the chuck 3.

[0037] Next, the index table 2 rotates, and the chuck 3 moves toward the rough grinding stage ST2.

[0038] Chuck 3 moves to the rough grinding stage ST2, and rough grinding is performed on the workpiece W1. During rough grinding, the grinding surface of the grinding wheel is pressed against the workpiece W1 while the rough grinding wheel and chuck 3 are rotated, and the workpiece W1 is roughly ground. When the measurement value of the first contact-type thickness measuring device 45 reaches the desired thickness, the rough grinding device 4 stops the rotation of the grinding wheel and chuck 3, retracts the grinding wheel upward, and ends the rough grinding.

[0039] Next, the index table 2 rotates, and the chuck 3 moves toward the intermediate grinding stage ST3. Intermediate grinding is performed on the workpiece W1 at the intermediate grinding stage ST3. During intermediate grinding, the grinding wheel and the chuck 3 are rotated, and the grinding surface of the grinding wheel is pressed against the workpiece W1 to perform intermediate grinding on the workpiece W1. When the measurement value of the second contact-type thickness measuring device 55 reaches the desired thickness, the intermediate grinding device 5 stops the rotation of the grinding wheel and the chuck 3, retracts the grinding wheel upward, and ends the intermediate grinding.

[0040] Next, the index table 2 rotates, and the chuck 3 moves toward the precision grinding stage ST4. Precision grinding is performed on the workpiece W1 at the precision grinding stage ST4. Specifically, as shown in Figures 3(a) to (c), during precision grinding, the grinding wheel 61 and the chuck 3 are rotated, and the grinding surface of the grinding wheel 61 is pressed against the workpiece W1 to perform precision grinding of the workpiece W1. When the measurement value of the non-contact thickness measuring device 63 reaches the desired thickness, the precision grinding device 6 stops the rotation of the grinding wheel 61 and the chuck 3, retracts the grinding wheel 61 upward, and ends the precision grinding. The measurement value of the non-contact thickness measuring device 63 at the end of precision grinding is set to the final target thickness plus a predetermined offset thickness.

[0041] Next, as the index table 2 rotates and the chuck 3 moves toward the platform stage ST1, the film thickness measuring device 7 measures the film thickness of the workpiece W1 at multiple measurement points across the entire surface of the workpiece W, as shown in Figure 3(d). The measurement points of the film thickness measuring device 7 on the workpiece W1 are set to, for example, 200 points. The film thickness measuring device 7, with its measurement points set on the rotational trajectory O of the central axis of the chuck 3 when viewed from a plane, can measure the film thickness of the workpiece W1 without reducing the grinding throughput of the workpiece W1 as the workpiece W1 rotates around the central axis of the chuck 3 and returns to the platform stage ST1.

[0042] Next, the control device 8 calculates the shape of the workpiece W1 after precision grinding based on the measurements from the film thickness measuring device 7. For example, the workpiece W1 shown in Figure 3(d) has a concave shape where the periphery is thicker than the center. The control device 8 calculates the tilt angle of the tilt mechanism so that the difference between the maximum and minimum film thicknesses is small for the first workpiece W1 processed. The relationship between the shape of the workpiece W1 and the tilt angle of the tilt mechanism is predetermined through experiments, etc.

[0043] <First workpiece (second stage of processing)> Next, rough grinding, intermediate grinding, and fine grinding are performed again on the workpiece W1 after fine grinding.

[0044] Specifically, the chuck 3, which holds the workpiece W1 after precision grinding, moves in the same order as the first stage of machining described above, through the rough grinding stage ST2, the intermediate grinding stage ST3, and the precision grinding stage ST4, and rough grinding, intermediate grinding, and precision grinding are performed sequentially on the workpiece W1 after precision grinding.

[0045] In the second stage of machining on the workpiece W1 after fine grinding in the rough grinding stage ST2, the intermediate grinding stage ST3, and the fine grinding stage ST4, as shown in Figures 4(a) and (b), the rotation axis 3a of the chuck 3 is tilted by the tilt angle of the tilt mechanism calculated based on the shape of the workpiece W1 after the first stage of fine grinding, and rough grinding, intermediate grinding, and fine grinding are performed.

[0046] Then, as shown in Figure 4(c), when the measurement value of the non-contact thickness measuring device 63 reaches the desired thickness, the precision grinding is terminated. The measurement value of the non-contact thickness measuring device 63 at the end of precision grinding is set to the final target thickness.

[0047] Next, as the index table 2 rotates and the chuck 3 moves toward the platform stage ST1, the film thickness measuring device 7 measures the film thickness at multiple measurement points across the entire surface of the workpiece W1, as shown in Figure 4(d).

[0048] The control device 8 then calculates the shape of the workpiece W1 after precision grinding based on the measurements from the film thickness measuring device 7. For example, the workpiece W1 shown in Figure 4(d) is formed to be approximately flat, with a smaller difference between its maximum and minimum thicknesses than the workpiece W1 after the first precision grinding stage. Furthermore, the control device 8 calculates the tilt angle of the tilt mechanism so that the difference between the maximum and minimum film thicknesses is small in the workpiece W1 after the second processing stage.

[0049] In this way, when the surface roughness of the precision grinding wheel 61 is set to a finer value (approximately 3-4 nm) than the conventional value (approximately 10-13 nm), if the second stage of machining is performed on the workpiece W1 after the first stage of machining using the precision grinding wheel 61, as in the conventional method, the precision grinding wheel 61 may not cut well, potentially causing the shape of the workpiece W1 after the second stage of machining to become unstable or the surface to burn. However, by performing the second stage of machining on the workpiece W1 after the first stage of machining in the order of rough grinding, medium grinding, and precision grinding, the precision grinding wheel 61 is sharpened and its cutting ability is maintained, allowing for stable machining of the workpiece W1.

[0050] Then, at platform stage ST1, the suction hold between workpiece W1 and chuck 3 is released, and workpiece W1 is transferred from chuck 3 to the cleaning device.

[0051] <Second worksheet> Next, the second workpiece W2 is held by suction in the same chuck 3 as the first workpiece W1, and rough grinding and intermediate grinding are performed on the second workpiece W2 in the same manner as the rough grinding and intermediate grinding processes performed on the first workpiece W1 described above. Note that in the rough grinding stage ST2 and the intermediate grinding stage ST3, the inclination angle of the rotation axis 3a of the chuck 3 is set to be approximately the same as when the first workpiece W1 was processed.

[0052] Subsequently, the index table 2 rotates, and the chuck 3 moves toward the precision grinding stage ST4. Precision grinding is performed on the workpiece W1 in the precision grinding stage ST4.

[0053] Specifically, as shown in Figure 5(a), first, the rotation axis 3a of the chuck 3 is tilted by the tilt angle of the tilt mechanism calculated based on the shape of the workpiece W1 after the second stage of grinding. That is, in the rough grinding stage ST2 and the intermediate grinding stage ST3, where the approximate shape of the workpiece W is determined, the machining is performed with the tilt angle of the rotation axis 3a of the chuck 3 set to approximately the same value relative to the workpiece W. In contrast, in the fine grinding stage ST4, where the fine shape of the workpiece W is determined, when machining the second workpiece W2, the tilt angle of the rotation axis 3a of the chuck 3 is set to take into account the machining result of the first workpiece W1.

[0054] Next, as shown in Figure 5(b), with the precision grinding wheel 61 and the chuck 3 rotating, the grinding surface of the precision grinding wheel 61 is pressed against the workpiece W2 to perform precision grinding of the workpiece W2.

[0055] Then, when the measurement value of the non-contact thickness measuring device 63 reaches the desired thickness, as shown in Figure 5(c), the precision grinding device 6 stops the rotation of the precision grinding wheel 61 and the chuck 3, and retracts the precision grinding wheel 61 upward, thereby ending the precision grinding.

[0056] In this way, the film thickness measuring device 7 quickly measures the film thickness of workpiece W1 after it has been processed, for workpieces W1 and W2 that are processed consecutively with the same chuck 3. The control device 8 calculates the inclination angle of the rotation axis 3a of the chuck 3 that allows workpiece W1 to be processed to be approximately flat based on the shape of workpiece W1. The precision grinding device 6 then precision grinds workpiece W2 with the rotation axis 3a of the chuck 3 inclined by this angle, thereby enabling efficient and highly accurate processing of workpiece W2 based on the processing results of workpiece W1.

[0057] Furthermore, in the rough grinding stage ST2 and the intermediate grinding stage ST3, where the approximate shape of the workpiece W is determined, the same conditions are applied to all workpieces W. In the fine grinding stage ST4, where the fine shape of the workpiece W is determined, the shape of the previously processed workpiece W is taken into consideration, and the workpiece W to be processed afterward is fine-ground at an angle. This allows for stable and highly accurate processing of multiple workpieces W.

[0058] Next, as the index table 2 rotates and the chuck 3 moves toward the platform stage ST1, the film thickness measuring device 7 measures the film thickness of the workpiece W2 at multiple measurement points across the entire surface of the workpiece W2, as shown in Figure 5(d). The number of measurement points for the film thickness measuring device 7 on the workpiece W2 is set to, for example, 200 points.

[0059] The control device 8 then calculates the shape of the workpiece W2 after precision grinding based on the measurements from the film thickness measuring device 7. For example, the workpiece W2 shown in Figure 5(d) has a smaller difference between its maximum and minimum thickness than the workpiece W1 and is formed to be approximately flat.

[0060] Subsequently, if necessary, for the third and subsequent workpieces W, the same process is carried out, calculating the tilt angle of the rotation axis 3a of the chuck 3 so that the difference between the maximum and minimum thickness of the most recently processed workpiece W is minimized, based on the shape of the most recently processed workpiece W using the same chuck 3. Then, grinding of the immediately following workpiece W is performed with the rotation axis 3a of the chuck 3 tilted by that angle.

[0061] Thus, the processing system 1 according to the present invention is a processing system 1 that processes a workpiece W in the order of rough grinding, medium grinding and fine grinding, and comprises a tilt device that can tilt the rotation axis 3a of a chuck 3 that holds the workpiece W, a film thickness measuring device 7 that measures the film thickness of the workpiece W after fine grinding in a non-contact manner, and a control device 8 that calculates the shape of the workpiece W after fine grinding based on the measurement value of the film thickness measuring device 7, calculates the tilt angle of the tilt device so that the difference between the maximum thickness and the minimum thickness of the workpiece W after fine grinding is small, and tilts the chuck 3 by the tilt angle, and is configured to reprocess the workpiece W after fine grinding in the order of rough grinding, medium grinding and fine grinding with the chuck 3 tilted by the tilt angle.

[0062] With this configuration, the film thickness measuring device 7 quickly measures the film thickness of the workpiece W1 after the first stage of processing, and the control device 8 calculates the inclination angle of the rotation axis 3a of the chuck 3 that allows the workpiece W1 to be processed to be approximately flat based on the shape of the workpiece W1. With the rotation axis 3a of the chuck 3 inclined by this angle, rough grinding, intermediate grinding, and fine grinding are performed again on the workpiece W1. As a result, even if the grinding wheel of the fine grinding device 6 is fine, the sharpness of the fine grinding wheel 61 is maintained by going through rough grinding and intermediate grinding, so that the workpiece W1 can be processed efficiently and with high precision.

[0063] Furthermore, by performing processing on the same workpiece W1 in two stages, there is a risk that the thermal expansion and contraction of the chuck 3, etc., due to the processing heat during grinding may not have subsided during the first stage of film thickness measurement. However, during the second stage of film thickness measurement, the thermal expansion and contraction of the chuck 3, etc., due to the processing heat during grinding will have subsided, allowing for accurate calculation of the shape of the workpiece W1.

[0064] Furthermore, the processing system 1 according to the present invention further includes an index table 2 for rotating the chuck 3 on the track O, and the film thickness measuring device 7 is configured to be installed on the track O when viewed from a planar perspective.

[0065] With this configuration, the measurement point of the film thickness measuring device 7 is set on the trajectory O of the index table 2 when viewed from a plane, so that the film thickness of the workpiece W can be measured without reducing the throughput of the grinding process of the workpiece W.

[0066] Furthermore, the present invention can be modified in various ways other than those described above, as long as it does not deviate from the spirit of the invention, and it goes without saying that the present invention extends to such modified forms. [Explanation of symbols]

[0067] 1: Processing System 2: Index Table 2a: Rotation axis (of index table 2) 3: Chuck 3a: (Chuck's) axis of rotation 31: Rotating Table 32: Adsorbent 4: Rough grinding device 41: First spindle 42: First spindle feed mechanism 43: Linear guide (for rough grinding equipment) 44: Ball screw slider mechanism (of a rough grinding machine) 45: First contact-type thickness measuring device 46, 47: Detection arm 5: Medium grinding device 51: The second spindle 52: Second spindle feed mechanism 53: Linear guide (for intermediate grinding equipment) 54: Ball screw slider mechanism (for intermediate grinding equipment) 55: Second contact-type thickness measuring device 56, 57: Detection arm 6: Precision grinding device 61: Fine grinding wheel 62: The Third Spindle 63: Non-contact thickness measuring device 7: Film thickness measuring device 8: Control device ST1: Platform Stage ST2: Rough grinding stage ST3: Intermediate grinding stage ST4: Precision grinding stage W, W1, W2: Work

Claims

1. A machining system that processes a workpiece in the order of pre-grinding and then fine grinding, A tilt device that allows the rotation axis of the chuck holding the workpiece to be tilted, A measuring device for measuring the film thickness of the workpiece after precision grinding, A control device that calculates the shape of the workpiece after precision grinding based on the measurement values ​​of the measuring device, calculates the tilt angle of the tilt device so that the difference between the maximum and minimum thickness of the workpiece after precision grinding is small, and tilts the chuck by the tilt angle, Equipped with, A machining system characterized by reworking a workpiece after precision grinding, which has a film thickness obtained by adding a predetermined offset thickness to the final target thickness, in the order of pre-grinding and precision grinding, with the chuck tilted by the aforementioned inclination angle.

2. The chuck is further provided with an index table that rotates the chuck along a predetermined track. The processing system according to claim 1, characterized in that the measuring device is installed on the track as viewed from a plane.

Images