Processing equipment

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 apparatus for planar processing of a workpiece.

Background Art

[0002] In the field of semiconductor manufacturing, a processing apparatus for planar processing of a semiconductor workpiece such as a silicon wafer (hereinafter referred to as "workpiece") to be thin and flat is known.

[0003] Patent Document 1 discloses a grinding apparatus that contacts a rotating grindstone 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

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when planar processing a workpiece, there is a risk of thickness variation in the processed workpiece due to the influence of the fixing surface accuracy of the workpiece and the mounting accuracy of processing tools such as grindstones. In order to eliminate such thickness variation, conventionally, it has been necessary to reassemble or adjust the fixing surface of the workpiece and the processing tool.

[0006] Furthermore, when infeed machining workpieces with shapes other than circular or workpieces with orientation flats (hereinafter collectively referred to as "non-circular workpieces"), the contact area between the grinding wheel and the workpiece is not constant for each predetermined rotation of the chuck table. In areas with a relatively large contact area, the amount of material removed from the workpiece tends to be small, while in areas with a relatively small contact area, the amount of material removed tends to be large. In other words, the thickness of the workpiece varies depending on the size of the contact area between the grinding wheel and the workpiece during machining, resulting in the problem that the workpiece cannot be finished to the desired thickness.

[0007] Therefore, a technical challenge arises in order to machine a workpiece to a desired thickness, and the present invention aims to solve this challenge. [Means for solving the problem]

[0008] To achieve the above objective, the processing apparatus according to the present invention is a processing apparatus for planar machining of a non-circular workpiece with a grinding wheel, comprising: an adsorbent capable of adsorbing and holding the workpiece; and an attachment provided on the outer circumference of the adsorbent, made of a material that is more difficult to machine than the adsorbent, and capable of contacting the grinding wheel during self-grinding of the adsorbent, wherein the attachment is provided on the outer circumference of the adsorbent in a region where the processing pressure at which the grinding wheel grinds the workpiece during planar machining is relatively low. Furthermore, in order to achieve the above objective, the processing apparatus according to the present invention is a processing apparatus for planar processing of a non-circular workpiece with a grinding wheel, comprising: a rectangularly shaped adsorbent capable of adsorbing and holding the workpiece; and an attachment provided on the outer circumference of the adsorbent, made of a material that is more difficult to machine than the adsorbent, and capable of contacting the grinding wheel during self-grinding to grind the adsorbent, wherein the attachment is provided on the outer circumference of the four corners of the adsorbent.

[0009] With this configuration, the thickness of the suction body after self-grinding in the area where the grinding wheel contacts the suction body and attachment becomes thicker than the thickness of the suction body after self-grinding in the area where the grinding wheel contacts the suction body, thereby compensating for variations in the thickness of the workpiece after planar machining. [Effects of the Invention]

[0010] This invention can reduce variations in the thickness of a workpiece after planar machining, which can be caused by factors such as the accuracy of the workpiece's fixing surface, the accuracy of the machining tool's mounting, or the shape of the workpiece. [Brief explanation of the drawing]

[0011] [Figure 1] A schematic diagram showing a processing apparatus relating to one embodiment of the present invention. [Figure 2] A perspective view showing a chuck table. [Figure 3] Figure 2 shows the chuck table, where (a) is a plan view and (b) is a cross-sectional view of AA within (a). [Figure 4] A schematic diagram illustrating the process of self-grinding. [Figure 5] A plan view comparing the contact area between the workpiece and the grinding wheel at two locations within the workpiece. [Figure 6] Schematic diagram showing the thickness of the workpiece after planar machining at two locations, as shown in Figure 5. [Figure 7] A plan view showing the positional relationship of the attachment to the adsorbent. [Figure 8] (a) is a schematic diagram showing the thickness at two locations within the adsorbent body after self-grinding, and (b) is a schematic diagram showing the thickness at two locations within the workpiece after planar machining. [Figure 9] A perspective view showing a chuck table applied to a processing apparatus according to a modified example of the present invention. [Figure 10] Figure 9 shows the chuck table, where (a) is a plan view and (b) is a cross-sectional view of the BB in (a). [Modes for carrying out the invention]

[0012] An embodiment of the present invention will be described based on the drawings. In the following, when referring to the number of components, numerical values, amounts, ranges, etc., unless otherwise specified or limited to a specific number in principle, it is not limited to that specific number, and it may be more than or less than the specific number.

[0013] Also, when referring to the shape, positional relationship, etc. of components, etc., unless otherwise specified or considered not to be so in principle, it includes those substantially approximating or similar to the shape, etc.

[0014] Also, the drawings may be exaggerated, such as enlarging characteristic parts for easy understanding of the features, and the dimensional ratios of components, etc. are not necessarily the same as the actual ones. Also, in sectional views, the hatching of some components may be omitted for easy understanding of the sectional structure of the components.

[0015] Also, in this embodiment, expressions indicating directions such as up and down, left and right, etc. are not absolute, and are appropriate when each component is in the posture depicted in the drawing, but should be interpreted as being changed according to the change in the posture when the posture changes.

[0016] The processing device 1 performs grinding on the workpiece W. As shown in FIG. 1, the processing device 1 includes a processing unit 2 and a holding unit 3.

[0017] The processing unit 2 includes a grinding wheel 21, a grinding wheel spindle 22, and an infeed mechanism 23.

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

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

[0020] The infeed mechanism 23 raises and lowers the grinding wheel spindle 22 vertically. The infeed mechanism 23 is a known configuration and consists, for example, of a plurality of linear guides that guide the direction of movement of the grinding wheel spindle 22 and a ball screw slider mechanism that raises and lowers the grinding wheel spindle 22. The infeed mechanism 23 is interposed between the grinding wheel spindle 22 and the column 24.

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

[0022] The chuck table 31 is equipped 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 equipped with a conduit (not shown) that runs through its interior and extends to its surface. The conduit is connected to a vacuum source, a compressed air source, or a water source via a rotary joint (not shown). When the vacuum source is activated, a negative pressure is created between the workpiece W placed on the adsorbent body 33 and the upper surface (adsorption surface 33a) of the adsorbent body 33, causing the workpiece W to be adsorbed and held by the adsorption surface 33a. When the compressed air source or water source is activated, the adsorption between the workpiece W and the adsorbent body 33 is released.

[0024] The adsorbent 33 is formed in a shape corresponding to the rectangular workpiece W when viewed from a plane.

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

[0026] As shown in Figure 2, the chuck table 31 has an annular recess 35 formed around the suction body 33. Multiple bolt holes 36 are formed at 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 suction body 33, but may be formed locally in the area where the attachment 37 described later can be attached.

[0027] An attachment 37 is mounted in the annular recess 35. Specifically, as shown in Figure 3(a), the attachment 37 is positioned to block the space between the four corners of the suction body 33 and the outer edge of the chuck table 31, along the radial direction of the chuck table 31 when viewed from above. The attachment 37 can be made of a hard-to-machine material with higher hardness than the suction body 33, for example, the same material as the dense body 34. Also, as shown in Figure 3(b), when the attachment 37 is mounted on the chuck table 31, the suction surface 33a and the upper surface (contact surface 37a) of the attachment 37 are substantially flush.

[0028] The attachment 37 has a bolt hole 38 formed through its top and bottom. The attachment 37 is detachably fastened to the chuck table 31 via a bolt 39. Preferably, the corners of the contact surface 37a are chamfered to suppress chipping by the grinding wheel 21.

[0029] The operation of the processing apparatus 1 is controlled by a control unit (not shown). The control unit controls each of the components that make up the processing apparatus 1. The control unit is composed of, for example, a CPU, memory, etc. The functions of the control unit may be realized by control using software or by operation using hardware.

[0030] Next, the self-grinding function of processing device 1 will be explained based on the drawings.

[0031] Self-grinding, as shown in Figure 4, is a process in which the grinding wheel 21 is brought close to the chuck table 31 by the infeed mechanism 23, and the suction surface 33a of the suction body 33 is ground with the grinding wheel 21. Self-grinding is performed as needed to maintain the suction surface 33a in the desired shape, and is generally performed prior to the planar machining of the workpiece W when the chuck table 31 is replaced.

[0032] When the processing device 1 performs planar machining on a non-circular workpiece W by bringing the machining surface of the grinding wheel 21 into parallel contact with the workpiece W, the amount of material removed (grinding amount) of the workpiece W may not be stable within the plane. The reason for this will be explained below with reference to Figure 5. In the following explanation, a square-shaped workpiece W in plan view will be used as an example, 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 the workpiece W so as to pass through the corner of the workpiece W and the rotation center 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 the workpiece W so as to pass through the center of the edge of the workpiece W and the rotation center O, it can be seen that the contact area A1 is about twice as wide as the contact area A2.

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

[0035] Therefore, in the processing device 1, the amount of self-grinding is locally increased or decreased within the adsorbent 33 in order to counteract the change in the thickness of the workpiece W that corresponds to the change in the contact area between the workpiece W and the grinding wheel 21 during planar machining.

[0036] Specifically, as shown in Figure 7, a first machining region R1 in which the amount of grinding of the workpiece W is relatively small and a second machining region R2 in which the amount of grinding of the workpiece W is relatively large are assumed, and an attachment 37 is placed on the outer circumference of the adsorbent 33 in the first machining region R1.

[0037] In this embodiment, the first processing area R1 is set in a sector shape with a central angle of ±15 degrees centered on the diagonal of the adsorbent 33, and the second processing area R2 is set in a roughly sector shape with a central angle of 60 degrees between adjacent first processing areas R1. The size of each processing area R1 and R2 may be appropriately changed according to the processing conditions of the workpiece W.

[0038] Furthermore, because the attachment 37 is made of a more difficult-to-machine material than the adsorbent 33, as shown in Figure 8(a), the amount of grinding of the adsorbent 33 in the first machining region R1 during self-grinding is less than the amount of grinding of the adsorbent 33 in the second machining region R2, so that the adsorbent 33 in the first machining region R1 is locally ground thicker.

[0039] Then, when the workpiece W is machined on a flat surface, as shown in Figure 8(b), the amount of grinding removed from the workpiece W in the first machining area R1 during flat surface machining is less than the amount of grinding removed from the workpiece W in the second machining area R2. Therefore, 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 planar machining is offset by the difference in thickness between the first machining area R1 and the second machining area R2 within the adsorbent 33, thereby reducing the thickness variation of the workpiece W after planar machining.

[0041] Furthermore, the suction body 33 and attachment 37 are not limited to the shapes described above. For example, when the chuck table 31 suctions and holds a workpiece W on which an orientation flat OF has been formed, 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 fan shape when viewed from above, as shown in Figures 9, 10(a), and (b).

[0042] In this manner, the processing apparatus 1 according to this embodiment is a processing apparatus 1 for planar machining of a workpiece W with a grinding wheel 21, and comprises a suction body 33 capable of adsorbing and holding the workpiece W, and an attachment 37 provided on the outer circumference of the suction body 33, made of a material that is more difficult to machine than the suction body 33, and capable of contacting the grinding wheel 21 during self-grinding to grind the suction body 33.

[0043] With this configuration, when the grinding wheel 21 performs planar machining on the workpiece W, the thickness of the adsorbent 33 after self-grinding in the first machining region R1 where the grinding wheel 21 contacts the adsorbent 33 and attachment 37 becomes thicker than the thickness of the adsorbent 33 after self-grinding in the second machining region R2 where the grinding wheel 21 contacts the adsorbent 33, thereby reducing variations in the thickness of the workpiece W after planar machining. This is achieved by offsetting the variation in the thickness of the workpiece W after planar machining.

[0044] Furthermore, in this embodiment, the processing apparatus 1 is configured such that the attachment 37 is detachably provided on the chuck table 31 that houses the suction body 33.

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

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

[0047] This configuration makes it possible to reduce variations in the thickness of the workpiece W after planar machining, which are caused by the shape of the workpiece W.

[0048] Furthermore, the present invention can be modified in various ways other than those described above, as long as it does not depart from the spirit of the invention, and it goes without saying that the present invention extends to such modifications. In addition, the embodiments and modifications described above may be combined with each other. [Explanation of Symbols]

[0049] 1: Processing equipment 2: Processing section 21: Sharpening stone 22: Grinding wheel spindle 23: Infeed mechanism 24: Column 3: Holding part 31: Chuck Table 32: Chuck Spindle 33: Adsorbent 33a: Adsorption surface 34 : Dense body 35: Annular recess 36: Bolt hole (in a dense material) 37: Attachment 37a: Contact surface 38: Bolt holes (of the attachment) 39: Bolt R1: First machining area R2: Second machining area W: Work

Claims

1. A processing device for planar machining of a non-circular workpiece using a grinding wheel, An adsorbent capable of adsorbing and holding the aforementioned workpiece, An attachment is detachably provided at a predetermined position on the outer circumference side of the suction body in the chuck table that houses the suction body, is made of a material that is more difficult to machine than the suction body, and is capable of contacting the grinding wheel during self-grinding of the suction body. Equipped with, The processing apparatus is characterized in that the attachment is provided on the outer circumference of the adsorbent in a region where the processing pressure at which the grinding wheel grinds the workpiece during planar machining of the workpiece is relatively low.

2. A processing device for planar machining of a non-circular workpiece using a grinding wheel, A rectangular-shaped adsorbent capable of adsorbing and holding the workpiece, An attachment is detachably provided at a predetermined position on the outer circumference side of the suction body in the chuck table that houses the suction body, is made of a material that is more difficult to machine than the suction body, and is capable of contacting the grinding wheel during self-grinding of the suction body. Equipped with, The processing apparatus is characterized in that the attachments are provided on the outer circumference of the four corners of the adsorbent body.

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