Processing device

Abstract

To provide a processing device which performs flattening to form a workpiece into a desired thickness.SOLUTION: A processing device 1 performs flattening to a non-circular workpiece W with a grindstone 21 and includes: an adsorbent 33 which may adsorb and hold the workpiece W; an attachment 37 which is provided at the outer periphery side of the adsorbent 33 and formed by a difficult-to-cut material which is more difficult to cut than the adsorbent 33 and may come into contact with the grindstone 21 during self-grinding for grinding the adsorbent 33. The attachment 37 is provided at the outer periphery side of the adsorbent 33 in an area where a processing pressure at which the grindstone 21 grinds the workpiece W during flattening of the workpiece W is relatively low.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a processing device for machining a workpiece into a flat surface. [Background technology]

[0002] 2. Description of the Related Art In the field of semiconductor manufacturing, processing devices are known that planarize semiconductor workpieces such as silicon wafers (hereinafter referred to as "workpieces") to make them thin and flat.

[0003] Patent Document 1 discloses a grinding device that brings a rotating grindstone into contact with the upper surface of a rectangular workpiece held on a chuck table, and grinds the rectangular workpiece to a predetermined thickness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5230982 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when machining a workpiece into a flat surface, there is a risk that the thickness of the machined workpiece may vary due to the influence of the accuracy of the workpiece fixing surface and the attachment accuracy of the grinding wheel and other machining tools. In order to eliminate such thickness variations, it was previously necessary to reassemble or adjust the workpiece fixing surface and machining tools.

[0006] Furthermore, when in-feed machining a workpiece of a shape other than a circle or a workpiece with an orientation flat (hereinafter collectively referred to as a "non-circular workpiece"), the contact area between the grindstone and the workpiece for each given rotation of the chuck table is not constant, and the amount of workpiece ground tends to be small in areas where the contact area is relatively large, and large in areas where the contact area is relatively small. In other words, there was a problem that the thickness of the workpiece varied depending on the size of the contact area between the grindstone and the workpiece during machining, making it impossible to finish the workpiece to the desired thickness.

[0007] Therefore, a technical problem arises that must be solved in order to plane-machine the workpiece to the desired thickness, and an object of the present invention is to solve this problem. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the processing device of the present invention is a processing device that performs flat processing of a non-circular workpiece with a grinding wheel, and comprises an adsorbent body capable of adsorbing and holding the workpiece, and an attachment that is provided on the outer periphery of the adsorbent body, is made of a material that is more difficult to cut than the adsorbent body, and is capable of contacting the grinding wheel during self-grinding to grind the adsorbent body, and the attachment is provided on the outer periphery of the adsorbent body in an area where the processing pressure with which the grinding wheel grinds the workpiece is relatively low during flat processing of the workpiece. In addition, in order to achieve the above-mentioned object, the processing device of the present invention is a processing device that uses a grinding wheel to flatten a non-circular workpiece, and is equipped with an adsorbent body that is formed in a rectangular shape and is capable of adsorbing and holding the workpiece, and an attachment that is provided on the outer periphery of the adsorbent body, is made of a material that is more difficult to cut than the adsorbent body, and is capable of contacting the grinding wheel during self-grinding to grind the adsorbent body, and the attachment is provided on the outer periphery of the four corners of the adsorbent body.

[0009] According to this configuration, the thickness of the adsorbent after self-grinding in the area where the grinding wheel contacts the adsorbent and the attachment is thicker than the thickness of the adsorbent after self-grinding in the area where the grinding wheel contacts the adsorbent, so as to offset the variation in thickness of the workpiece after flat surface processing, thereby reducing the variation in thickness of the workpiece after flat surface processing. Effect of the Invention

[0010] The present invention can reduce variations in thickness of a workpiece after flattening, which are caused by the accuracy of the fixing surface of the workpiece, the attachment accuracy of the machining tool, or the shape of the workpiece. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a processing device according to an embodiment of the present invention; [Diagram 2] FIG. [Diagram 3] 3A and 3B are diagrams showing the chuck table in FIG. 2, in which FIG. 3A is a plan view and FIG. 3B is a cross-sectional view taken along the line AA in FIG. [Figure 4] Schematic diagram showing self-grinding. [Diagram 5] A plan view comparing the contact areas between the workpiece and the grinding wheel at two points within the workpiece. [Figure 6] 6 is a schematic diagram showing the thickness of the workpiece after flattening at the two locations shown in FIG. 5. [Figure 7] FIG. 4 is a plan view showing the positional relationship of an attachment with respect to an adsorption body. [Figure 8] (a) is a schematic diagram showing the thickness after self-grinding at two points in the adsorption body, and (b) is a schematic diagram showing the thickness after flattening at two points in the workpiece. [Figure 9] FIG. 11 is a perspective view showing a chuck table applied to a processing device according to a modified example of the present invention. [Figure 10] 10A and 10B are diagrams showing the chuck table in FIG. 9, in which (a) is a plan view and (b) is a cross-sectional view taken along line BB in (a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of the present invention will be described with reference to the drawings. In the following, when the number, numerical value, amount, range, etc. of components are mentioned, the number is not limited to the specific number, and may be more or less than the specific number, unless otherwise specified or when it is clearly limited to a specific number in principle.

[0013] In addition, when referring to the shape or positional relationship of components, etc., this includes things that are substantially similar or approximate to those shapes, etc., unless otherwise specified or considered to be clearly different in principle.

[0014] In addition, the drawings may exaggerate characteristic parts to make the features easier to understand, and the dimensional ratios of the components may not be the same as the actual ones. 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.

[0015] Furthermore, in this embodiment, expressions indicating directions such as up / down and left / right are not absolute, but are appropriate when each component is in the position depicted in the drawing, but if the position changes, they should be interpreted differently in accordance with the change in position.

[0016] The processing device 1 performs grinding on a workpiece W. As shown in FIG.

[0017] The processing section 2 includes a grindstone 21, a grindstone spindle 22, and an in-feed mechanism .

[0018] The grindstone 21 is, for example, a cup-shaped grindstone, and is attached to the lower end of a grindstone spindle 22 .

[0019] The grindstone spindle 22 is rotatable around a rotation axis 2a, and the grindstone 21 and the grindstone spindle 22 are configured to be rotatable together.

[0020] The in-feed mechanism 23 vertically raises and lowers the grindstone spindle 22. The in-feed mechanism 23 has a known configuration and is composed of, for example, a plurality of linear guides that guide the movement direction of the grindstone spindle 22, and a ball screw slider mechanism that raises and lowers the grindstone spindle 22. The in-feed mechanism 23 is interposed between the grindstone spindle 22 and a column 24.

[0021] The holding unit 3 includes a chuck table 31 and a chuck spindle 32 .

[0022] The chuck table 31 is provided with an adsorbent 33 made of a porous material such as alumina on its upper surface, and a dense body 34 in which the adsorbent 33 is embedded approximately in the center.

[0023] The chuck table 31 is provided with a conduit (not shown) that runs through the inside and extends to the surface. The conduit 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, negative pressure is generated between the workpiece W placed on the adsorber 33 and the upper surface (adsorption surface 33a) of the adsorber 33, and the workpiece W is adsorbed and held on the adsorption surface 33a. When the compressed air source or water supply source is activated, the adsorption between the workpiece W and the adsorber 33 is released.

[0024] The attraction body 33 is formed in a shape corresponding to the workpiece W, which is rectangular in plan view.

[0025] The chuck spindle 32 is configured to rotate the chuck table 31 about a rotation axis 3a. A drive source for the chuck spindle 32 may be, for example, a servo motor.

[0026] 2, an annular recess 35 is formed in the chuck table 31 so as to surround the attraction body 33. A plurality of bolt holes 36 are formed in the bottom of the annular recess 35. Note that the annular recess 35 does not need to be formed around the entire circumference of the attraction body 33, and may be formed locally in an area where an attachment 37, which will be described later, can be attached.

[0027] An attachment 37 is attached to the annular recess 35. Specifically, as shown in Fig. 3(a), the attachment 37 is provided along the radial direction of the chuck table 31 in a plan view so as to block the gaps between the four corners of the adsorption body 33 and the outer edge of the chuck table 31. The attachment 37 may be made of a hard-to-cut material that is harder than the adsorption body 33, for example, made of the same material as the dense body 34. In addition, as shown in Fig. 3(b), when the attachment 37 is attached to the chuck table 31, the adsorption surface 33a and the upper surface (contact surface 37a) of the attachment 37 are substantially flush with each other.

[0028] The attachment 37 has a bolt hole 38 formed therethrough from top to bottom. The attachment 37 is detachably fastened to the chuck table 31 via a bolt 39. It is preferable that the corners of the contact surface 37a are chamfered to suppress chipping by the grindstone 21.

[0029] The operation of the processing device 1 is controlled by a control unit (not shown). The control unit controls each of the components constituting the processing device 1. The control unit is composed of, for example, a CPU, a memory, and the like. The functions of the control unit may be realized by controlling using software, or may be realized by operating using hardware.

[0030] Next, the self-grinding of the processing device 1 will be described with reference to the drawings.

[0031] Self-grinding refers to a process in which the grindstone 21 is brought close to the chuck table 31 by the in-feed mechanism 23, and the grindstone 21 grinds the adsorption surface 33a of the adsorption body 33, as shown in Fig. 4. Self-grinding is performed as necessary to maintain the adsorption surface 33a in a desired shape, and is generally performed prior to flattening the workpiece W when the chuck table 31 is replaced.

[0032] When the processing device 1 performs planar processing of the workpiece W by bringing the processing surface of the grinding wheel 21 into contact parallel with the processing surface of the non-circular workpiece W, the processing amount (grinding amount) of the workpiece W may not be stable within the surface. The reason for this will be explained below with reference to Fig. 5. Note that, in the following, an example of a workpiece W that is square in plan view will be explained, but the shape of the workpiece W is not limited to this.

[0033] As shown in Figure 5, when comparing the contact area A1 between the workpiece W and the grinding wheel 21 when the machining surface of the grinding wheel 21 contacts so as to pass through the corners of the workpiece W and the center of rotation O of the chuck table 31, with the contact area A2 between the workpiece W and the grinding wheel 21 when the machining surface of the grinding wheel 21 contacts so as to pass through the center of the side of the workpiece W and the center of rotation O, it can be seen that the contact area A1 is approximately twice as large as the contact area A2.

[0034] When the grindstone 21 is brought into uniform contact with the workpiece W over the entire surface, as the contact area between the workpiece W and the grindstone 21 increases, the amount of workpiece W ground decreases and the workpiece W after processing becomes thicker. That is, when comparing the thickness of the workpiece W after grinding in the contact areas A1 and A2, the workpiece W in the contact area A2 is formed thicker than the workpiece W in the contact area A1, as shown in Fig. 6. For example, in the case of a 280 mm square workpiece W, the end P2 of the contact area A2 is ground to be about 4 µm thinner than the end P1 of the contact area A1.

[0035] Therefore, in the processing device 1, the grinding amount of the self-grinding is locally increased or decreased within the adsorption body 33 so as to offset the change in thickness of the workpiece W that corresponds to the change in the contact area between the workpiece W and the grinding wheel 21 during flat surface processing.

[0036] Specifically, as shown in Figure 7, a first machining area R1 in which the amount of workpiece W that is ground during flat surface machining is relatively small and a second machining area R2 in which the amount of workpiece W that is ground is relatively large are assumed, and an attachment 37 is placed on the outer periphery of the adsorption body 33 in the first machining area R1.

[0037] In this embodiment, the first machining area R1 is set in a sector shape with a central angle of ±15 degrees centered on the diagonal line of the adsorption body 33, and the second machining area R2 is set between adjacent first machining areas R1 in a roughly sector shape with a central angle of 60 degrees. The size of each machining area R1, R2 may be changed as appropriate depending on the machining conditions of the workpiece W, etc.

[0038] Furthermore, because the attachment 37 is made of a material that is more difficult to cut than the adsorption body 33, as shown in Figure 8(a), the amount of adsorption body 33 ground away in the first machining area R1 during self-grinding is less than the amount of adsorption body 33 ground away in the second machining area R2, and as a result, the adsorption body 33 in the first machining area R1 is ground away locally to a thicker thickness.

[0039] Then, when the workpiece W is subjected to flat surface machining, as shown in FIG. 8(b), the amount of workpiece W ground in the first machining area R1 during flat surface machining is less than the amount of workpiece W ground in the second machining area R2, so that the workpiece W in the first machining area R1 is machined to be thicker than the workpiece W in the second machining area R2.

[0040] In this way, the difference in the amount of grinding between the first machining area R1 and the second machining area R2 during flat surface machining is offset by the difference in thickness between the first machining area R1 and the second machining area R2 within the adsorption body 33, thereby reducing the variation in thickness of the workpiece W after flat surface machining.

[0041] It should be noted that the suction body 33 and the attachment 37 are not limited to the shapes described above. For example, when the chuck table 31 suction-holds a workpiece W having an orientation flat OF, as shown in Figures 9, 10(a) and (b), the suction body 33 may be formed in a circular shape when viewed from above, and the attachment 37 may be formed in an annular sector shape when viewed from above.

[0042] In this way, the processing device 1 according to this embodiment is a processing device 1 that performs flat processing on the workpiece W with a grinding wheel 21, and is configured to include an adsorbent 33 capable of adsorbing and holding the workpiece W, and an attachment 37 that is provided on the outer periphery of the adsorbent 33, is made of a material that is more difficult to cut than the adsorbent 33, and is capable of contacting the grinding wheel 21 during self-grinding to grind the adsorbent 33.

[0043] According to this configuration, in order to offset the variation in thickness of the workpiece W after processing caused by the contact area between the grinding wheel 21 and the workpiece W changing depending on the rotation angle of the chuck table 31 when the grinding wheel 21 processes the workpiece W into a flat surface, the thickness of the adsorbent 33 after self-grinding in the first processing region R1 where the grinding wheel 21 contacts the adsorbent 33 and the attachment 37 is thicker than the thickness of the adsorbent 33 after self-grinding in the second processing region R2 where the grinding wheel 21 contacts the adsorbent 33, thereby reducing the variation in thickness of the workpiece W after flat surface processing.

[0044] Moreover, the processing device 1 according to this embodiment is configured such that the attachment 37 is detachably provided on the chuck table 31 that houses the adsorption body 33.

[0045] According to this configuration, the position of the attachment 37 relative to the attraction body 33 can be changed, so that the shape of the attraction body 33 after self-grinding can be changed according to the shape of the workpiece W and the processing conditions.

[0046] Moreover, the processing device 1 according to this embodiment is configured so that the workpiece W is formed in a non-circular shape.

[0047] According to this configuration, the variation in thickness of the workpiece W after flattening, which is caused by the shape of the workpiece W, can be reduced.

[0048] Furthermore, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention, and the present invention naturally includes such modified versions. Furthermore, the above-described embodiments and modifications may be combined with each other. [Explanation of symbols]

[0049] 1: Processing equipment 2: Processing section 21: Grindstone 22: Grindstone spindle 23: Infeed mechanism 24: Column 3: Holding part 31: Chuck table 32: Chuck spindle 33: Adsorbent 33a: Adsorption surface 34 : Dense body 35: Circular recess 36: Bolt hole (in dense body) 37: Attachment 37a: Contact surface 38: (Attachment) bolt hole 39: Bolt R1: First machining area R2: Second machining area W: Work

Claims

1. A processing device that processes a non-circular workpiece into a flat surface using a grindstone, An adsorption body capable of adsorbing and holding the workpiece; an attachment provided on an outer periphery of the adsorbent body, made of a material harder to cut than the adsorbent body, and capable of contacting the grindstone during self-grinding to grind the adsorbent body; Equipped with The processing device is characterized in that the attachment is provided on the outer periphery of the suction body in an area where the processing pressure with which the grinding wheel grinds the workpiece during flat surface processing of the workpiece is relatively low.

2. A processing device that processes a non-circular workpiece into a flat surface using a grindstone, An adsorption body formed in a rectangular shape and capable of adsorbing and holding the workpiece; an attachment provided on an outer periphery of the adsorbent body, made of a material harder to cut than the adsorbent body, and capable of contacting the grindstone during self-grinding to grind the adsorbent body; Equipped with The processing device is characterized in that the attachments are provided on the outer periphery of the four corners of the suction body.

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