Dirt-proof cover

Abstract

To prevent sticking of a stain to a frame holding part for holding a frame used for machining a workpiece.SOLUTION: A stain sticking prevention cover is fitted to a frame holding part of a machining device provided with a chuck table having a holding surface for holding a workpiece, the frame holding part having a support surface fixed to the peripheral edge of a tape stuck to the workpiece and used to support an annular frame made of a ferromagnetic body and a magnet for fixing the frame supported on the support surface to the support surface by means of a magnetic force, and a machining unit that machines the workpiece held on the chuck table. This cover comprises: a body having a first surface of a size to be able to cover the entire support surface; and a fitting part made of a ferromagnetic body and disposed on the first surface side of the body, and is fitted to the frame holding body by means of a magnetic force of the magnet applied on the fitting part by disposing the first surface oppositely to the support surface when the workpiece is machined without using the frame.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a dirt-preventing cover that prevents dirt from adhering to a frame holding portion that holds a frame used when processing a workpiece. [Background technology]

[0002] In order to realize small and lightweight device chips that can be incorporated into various electronic devices, there are increasing opportunities to thin workpieces such as semiconductor wafers that have devices such as integrated circuits mounted on their surface. For example, the workpiece can be thinned by holding one surface (the held surface) of the workpiece on a chuck table, rotating a grinding wheel with a grinding stone containing abrasive grains fixed to the chuck table relative to the other surface of the workpiece while supplying a liquid such as water.

[0003] In the grinding of the workpiece described above, a negative pressure suction (vacuum suction) chuck table is used, which has a holding surface on the top that can apply negative pressure to the workpiece so that the entire workpiece can be securely held. However, when an attempt is made to hold a workpiece that is smaller than this holding surface with the chuck table, negative pressure leaks from the gap between the held surface of the workpiece and the holding surface of the chuck table, making it impossible to properly hold the entire workpiece with the chuck table.

[0004] Furthermore, for example, if a workpiece is ground until it is thinner than 100 μm, the strength of the workpiece is significantly reduced, making the workpiece more susceptible to damage when it is subsequently held and transported. Therefore, a method has been proposed in which a tape larger than the target workpiece is attached to the workpiece and an annular frame is fixed to the peripheral edge of this tape to prevent leakage of negative pressure from the holding surface and damage to the workpiece during transport (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-141122 Summary of the Invention [Problem to be solved by the invention]

[0006] The frame used in the above-described method is made of a ferromagnetic body (ferromagnetic material) such as iron, and a frame holding part having a magnet on its upper surface is disposed adjacent to the chuck table. Therefore, when the frame fixed to the peripheral edge of the tape is placed on the upper surface of the frame holding part, the frame is fixed to the frame holding part by the magnetic force (attractive force) of the magnet provided in the frame holding part.

[0007] The above-described holding unit, which is composed of a chuck table and a frame holding part, can also be used when processing a workpiece without using a frame. However, in this case, the workpiece is processed with the upper surface of the frame holding part exposed, and therefore the upper surface of the frame holding part is easily soiled with debris generated during processing.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to prevent dirt from adhering to a frame holding portion that holds a frame used when processing a workpiece. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a dirt prevention cover that is attached to the frame holding part of a processing device that includes: a chuck table having a holding surface that holds a workpiece; a support surface that supports an annular frame made of a ferromagnetic material and that is used by being fixed to the peripheral edge of a tape that is attached to the workpiece; a frame holding part that has a magnet that fixes the frame supported on the support surface to the support surface with magnetic force; and a processing unit that processes the workpiece held on the chuck table. The dirt prevention cover is attached to the frame holding part of the processing device, and includes: a main body having a first surface that is large enough to cover the entire support surface; and an attachment part that is arranged on the first surface side of the main body and is made of a ferromagnetic material, When the diameter of the workpiece is smaller than the diameter of the holding plate of the chuck table, the tape having a diameter larger than that of the workpiece is attached to the workpiece, the frame is fixed to the peripheral edge of the tape, and the frame is supported by the support surface of the frame holding part. However, when the diameter of the workpiece is the same as or larger than the diameter of the holding plate, the tape is not placed on the support surface of the frame holding part, The frame teeth use NotThe first surface is made to face the support surface, and the second surface acts on the mounting portion. Frame holder Due to the magnetic force of the magnet The dirt adhesion prevention cover Attached to the frame holding part The frame is fixed to the support surface in a manner that the frame is in contact with the tape on the support surface of the frame holding portion covered with the tape, and the dirt adhesion prevention cover prevents dirt from adhering to the support surface of the frame holding portion that is not covered with the tape. A dirt-repellent cover is provided.

[0010] Preferably, the main body has a second surface opposite to the first surface, and the second surface is inclined relative to the first surface.

[0011] Preferably, the main body has a second surface opposite to the first surface, and the second surface of the main body has a magnet. It can also attract ferromagnetic debris. The suction portion is disposed. [Effects of the Invention]

[0012] A dirt-proof cover according to one aspect of the present invention includes a main body having a first surface large enough to cover the entire support surface of a frame holder, and an attachment portion arranged on the first surface side of the main body and made of a ferromagnetic material. For example, when a workpiece is processed without using a frame, the dirt-proof cover can be attached to the frame holder by facing the first surface to the support surface of the frame holder and allowing the magnetic force of the magnet in the frame holder to act on the attachment portion. Therefore, even when a workpiece is processed without using a frame, dirt can be prevented from adhering to the frame holder. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view that schematically shows a grinding machine in which a dirt adhesion prevention cover according to this embodiment is used. [Figure 2] FIG. 2 is a perspective view schematically showing the dirt adhesion prevention cover. [Figure 3] FIG. 3 is a bottom view schematically showing the dirt adhesion prevention cover. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a part of the dirt adhesion prevention cover. [Figure 5] FIG. 5 is a cross-sectional view that schematically shows a grinding device equipped with a dirt adhesion prevention cover. [Figure 6] FIG. 6 is a cross-sectional view schematically showing a part of a dirt adhesion prevention cover according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a cross-sectional view schematically showing a grinding device (processing device) 2 in which a dirt adhesion prevention cover of this embodiment is used. As shown in Fig. 1, the grinding device 2 of this embodiment is configured to be able to grind a plate-shaped workpiece 11.

[0015] The workpiece 11 is, for example, a wafer formed into a disk shape using a semiconductor such as silicon (Si), and has a circular front surface 11a and a circular back surface 11b opposite to the front surface 11a. The front surface 11a side of the workpiece 11 is divided into a plurality of small regions by a plurality of mutually intersecting planned division lines (streets), and a device such as an IC (Integrated Circuit) is formed in each small region.

[0016] For example, the back surface 11b of the workpiece 11 is ground by the grinding device 2. Before grinding the back surface 11b of the workpiece 11, a tape 13 made of resin or the like is attached to the front surface 11a of the workpiece 11. This allows the tape 13 to absorb the impact applied to the front surface 11a when grinding the back surface 11b, thereby protecting the devices and the like of the workpiece 11.

[0017] In this embodiment, the workpiece 11 is a disk-shaped wafer made of a semiconductor such as silicon, but there are no limitations on the material, shape, structure, size, etc. of the workpiece 11. For example, a substrate made of other semiconductors, ceramics, resin, metal, etc. can also be used as the workpiece 11. Similarly, there are no limitations on the type, number, shape, structure, size, arrangement, etc. of devices. The workpiece 11 does not have to have any devices formed on it.

[0018] As shown in Fig. 1, the grinding apparatus 2 is equipped with a chuck table 4 configured to hold a plate-shaped workpiece 11. The chuck table 4 includes a disk-shaped frame 6 made of, for example, ceramics, metal, or the like. A recess 6a having a circular opening at its upper end is formed on the upper surface of the frame 6. A porous disk-shaped holding plate 8 made of, for example, ceramics is embedded and fixed in this recess 6a.

[0019] The upper surface (holding surface) 8a of the holding plate 8 has a shape corresponding to, for example, the side surface of a cone. A suction source (not shown) such as an ejector is connected to the lower surface of the holding plate 8 via a flow path 6b provided inside the frame 6, a valve (not shown), or the like. Therefore, when the valve is opened while the suction source is activated, negative pressure generated by the suction source acts on the upper surface 8a of the holding plate 8.

[0020] Therefore, for example, if tape 13 is brought into contact with upper surface 8a of holding plate 8 and negative pressure is applied to upper surface 8a of holding plate 8, tape 13 will be sucked onto upper surface 8a of holding plate 8. In other words, workpiece 11 is held onto upper surface 8a of chuck table 4 via tape 13. Note that while the shape of the conical side surface that constitutes upper surface 8a of holding plate 8 is exaggerated in FIG. 1, in reality, the difference in height (height difference) between the highest point and the lowest point of upper surface 8a is approximately 10 μm to 30 μm.

[0021] A rotational drive source (not shown), such as a motor, is connected to the lower part of the frame 6. The force generated by this rotational drive source causes the chuck table 4 to rotate about an axis along the vertical direction or an axis slightly tilted relative to the vertical direction, with the apex 8b of the upper surface 8a, which corresponds to the apex of the cone, as the center of rotation. The frame 6 is supported by a movement mechanism (not shown), and the force generated by this movement mechanism causes the chuck table 4 to move horizontally.

[0022] Incidentally, when the diameter (width) of the workpiece 11 is smaller than the diameter (width) of the holding plate 8, as shown in Fig. 1, a tape 13 having a diameter (width) larger than that of the workpiece 11 is attached to the workpiece 11, and an annular frame 15 is fixed to the peripheral edge of this tape 13. For this reason, a frame holding portion 10 capable of holding the frame 15 is provided around the periphery of the frame body 6 constituting the chuck table 4.

[0023] The frame holding unit 10 includes an annular holding unit main body 12 having a generally flat upper surface (support surface) 12a capable of supporting a frame 15, and a plurality of magnets 14 arranged so as to be embedded in the upper surface (support surface) 12a of the holding unit main body 12 along the circumferential direction of the holding unit main body 12. The frame 15 is typically made of a ferromagnetic material such as iron, and when placed on the upper surface 12a of the holding unit main body 12, it is fixed to the upper surface 12a by the magnetic force of the magnets 14.

[0024] A grinding unit (processing unit) 20 is disposed above the chuck table 4 and the frame holding part 10. The grinding unit 20 includes, for example, a cylindrical spindle housing (not shown). A columnar spindle 22 is housed in the space inside the spindle housing.

[0025] A disk-shaped mount 24 is provided at the lower end of the spindle 22. A plurality of holes (not shown) are formed on the outer periphery of the mount 24, penetrating the mount 24 in the thickness direction, and a bolt 26 or the like is inserted into each hole. A disk-shaped grinding wheel 28 having roughly the same diameter as the mount 24 is fixed to the underside of the mount 24 by the bolt 26 or the like.

[0026] The grinding wheel 28 includes a disk-shaped wheel base 30 made of a metal such as stainless steel or aluminum. A plurality of grinding stones 32 are fixed to the underside of the wheel base 30 along the circumferential direction of the wheel base 30. A rotational drive source (not shown), such as a motor, is connected to the upper end of the spindle 22. The force generated by this rotational drive source causes the grinding wheel 28 to rotate about an axis that is aligned vertically or slightly tilted relative to the vertical.

[0027] A nozzle (not shown) configured to supply a liquid for grinding (typically water) to the grinding stone 32 and the like is provided near the grinding wheel 28 or inside the grinding wheel 28. The spindle housing is supported, for example, by a movement mechanism (not shown), and the grinding unit 20 moves vertically by the force generated by this movement mechanism.

[0028] When grinding the workpiece 11, first, the chuck table 4 is moved directly below the grinding unit 20. Then, as shown in FIG. 1, the chuck table 4 and the grinding wheel 28 are rotated, and the grinding unit 20 is lowered while liquid is supplied from the nozzle. The speed at which the grinding unit 20 is lowered is adjusted to a range in which the grinding stone 32 is pressed against the workpiece 11 with an appropriate pressure. This allows the workpiece 11 to be ground from the back surface 11b side, thereby thinning it.

[0029] Fig. 2 is a perspective view that schematically shows the dirt-proof cover 1 that is attached to the frame holding part 10, Fig. 3 is a bottom view that schematically shows the dirt-proof cover 1, and Fig. 4 is a cross-sectional view that schematically shows a part of the dirt-proof cover 1. As shown in Figs. 2, 3, and 4, the dirt-proof cover 1 includes an annular cover main body (main body) 3 that has a bottom surface (first surface) 3a that is large enough to cover the entire top surface 12a of the frame holding part 10.

[0030] The diameter of the inner peripheral edge 3c of the cover body 3 is equal to or smaller than the diameter of the inner peripheral edge of the holder body 12. On the other hand, the diameter of the outer peripheral edge 3d of the cover body 3 is equal to or larger than the diameter of the outer peripheral edge of the holder body 12. In other words, the distance (width) between the inner peripheral edge 3c and the outer peripheral edge 3d of the cover body 3 is equal to or larger than the distance (width) between the inner peripheral edge and the outer peripheral edge of the holder body 12.

[0031] An annular ferromagnetic member (attachment portion) 5 made of a ferromagnetic material such as iron is embedded in the underside 3a of the cover body 3. Therefore, when the cover body 3 is placed on the frame holding portion 10 so that the underside 3a faces the upper surface 12a of the holding portion main body 12, the magnetic force of the magnet 14 acts on the ferromagnetic member 5, and the dirt adhesion prevention cover 1 is attached to the frame holding portion 10.

[0032] As a result, the entire upper surface 12a of the frame holding part 10 is covered with the cover body 3, which prevents dirt from adhering to the upper surface 12a of the frame holding part 10. The upper surface (second surface) 3b of the cover body 3, which is located on the opposite side to the lower surface 3a, is inclined with respect to the lower surface 3a.

[0033] Specifically, the upper surface 3b is inclined relative to the lower surface 3a so that the thickness of the dirt-proof cover 1 is thinner on the inner peripheral edge 3c side and the outer peripheral edge 3d side of the dirt-proof cover 1 compared to the radial center side of the dirt-proof cover 1. Therefore, debris generated from the workpiece 11 during grinding is quickly discharged from the upper surface 3b along with the liquid used during grinding, and almost no debris remains on this upper surface 3b. This makes the dirt-proof cover 1 easy to clean.

[0034] Fig. 5 is a cross-sectional view schematically showing the grinding device 2 equipped with the dirt adhesion prevention cover 1. As shown in Fig. 5, when the diameter (width) of the workpiece 21 to be ground is, for example, approximately the same as or larger than the diameter (width) of the holding plate 8, a tape 23 having a diameter (width) approximately the same as that of the workpiece 11 is attached to the surface 21a of the workpiece 21, as shown in Fig. 5. On the other hand, in this case, the annular frame as shown in Fig. 1 is not used.

[0035] In this way, when grinding the workpiece 21 without using an annular frame, the dirt-proof cover 1 is attached to the frame holding part 10. As a result, the top surface 12a of the frame holding part 10 is not exposed and is covered with the dirt-proof cover 1, so that debris generated by grinding the back surface 21b side of the workpiece 21 does not adhere to the top surface 12a of the frame holding part 10.

[0036] As described above, the dirt-proof cover 1 according to this embodiment includes the cover main body (main body portion) 3 having the lower surface (first surface) 3a large enough to cover the entire upper surface (support surface) 12a of the frame holding portion 10, and the ferromagnetic member (mounting portion) 5 made of a ferromagnetic material and disposed on the lower surface 3a side of the cover main body 3. Therefore, for example, when the workpiece 21 is ground without using a frame, the dirt-proof cover 1 can be attached to the frame holding portion 10 by facing the lower surface 3a to the upper surface 12a of the frame holding portion 10 and allowing the magnetic force of the magnet 14 of the frame holding portion 10 to act on the ferromagnetic member 5. Therefore, even when the workpiece 21 is ground without using a frame, the dirt-proof cover 1 can be prevented from adhering to the frame holding portion 10.

[0037] The present invention is not limited to the above-described embodiment and can be implemented with various modifications. For example, in the above-described embodiment, the cover body 3 of the dirt adhesion prevention cover 1 and the ferromagnetic member 5 made of a ferromagnetic material are configured as separate parts, but these may be configured as an integrated ferromagnetic material. At least the mounting portion made of a ferromagnetic material needs to be located on the lower surface (first surface) of the main body.

[0038] Furthermore, in the above-described embodiment, one annularly configured holding body 12 is used, but there are no particular limitations on the shape or number of the holding body that constitutes the frame holding unit 10. For example, multiple holding body bodies can be discretely arranged along the circumferential direction of the chuck table 4.

[0039] In this case, it is advisable to change the shape of the dirt adhesion prevention cover 1 according to the shape of the holder body, as well as the shape and number of the magnets constituting the frame holder 10. For example, the magnets may be configured in a ring shape surrounding the chuck table 4.

[0040] Furthermore, in the above-described embodiment, a grinding device 2 equipped with a grinding unit 20 was described as an example of a processing device to which a dirt-adhesion prevention cover 1 is attached, but the processing device to which a dirt-adhesion prevention cover 1 is attached may also be a cutting device including a cutting unit (processing unit) to which a ring-shaped cutting blade is attached.

[0041] Furthermore, the dirt-proof cover 1 described above is configured so that dirt such as chips generated during grinding is unlikely to remain on the cover itself, but the dirt-proof cover of the present invention is only required to be configured so as to be able to prevent dirt from adhering to at least the frame holding portion 10. For example, the upper surface (second surface) 3b of the dirt-proof cover 1 is 3 It does not have to be inclined relative to a.

[0042] Fig. 6 is a cross-sectional view schematically showing a part of a modified dirt adhesion prevention cover 31. As shown in Fig. 6, the modified dirt adhesion prevention cover 31 includes an annular cover main body (main body portion) 33 having a lower surface (first surface) 33a large enough to cover the entire upper surface (support surface) 12a of the frame holding portion 10.

[0043] The diameter of the inner peripheral edge 33c of the cover body 33 is equal to or smaller than the diameter of the inner peripheral edge of the holder body 12. On the other hand, the diameter of the outer peripheral edge 33d of the cover body 33 is equal to or larger than the diameter of the outer peripheral edge of the holder body 12. In other words, the distance (width) between the inner peripheral edge 33c and the outer peripheral edge 33d of the cover body 33 is equal to or larger than the distance (width) between the inner peripheral edge and the outer peripheral edge of the holder body 12.

[0044] An annular ferromagnetic member (attachment portion) 35 made of a ferromagnetic material such as iron is embedded in the underside 33a of the cover body 33. Therefore, when the cover body 33 is placed on the frame holding portion 10 so that the underside 33a faces the upper surface 12a of the holding portion body 12, the magnetic force of the magnet 14 acts on the ferromagnetic member 35, and the dirt adhesion prevention cover 31 is attached to the frame holding portion 10.

[0045] As a result, the entire upper surface 12a of the frame holding part 10 is covered with the cover main body 33, preventing dirt from adhering to the upper surface 12a of the frame holding part 10. Note that the upper surface (second surface) 33b of the cover main body 33, which is located on the opposite side to the lower surface 33a, is inclined with respect to the lower surface 33a. Specifically, the upper surface 33b is inclined with respect to the lower surface 33a so that the thickness of the dirt adhesion prevention cover 31 is thicker on the inner peripheral edge 33c side and the outer peripheral edge 33d side of the dirt adhesion prevention cover 31 than on the radial center side of the dirt adhesion prevention cover 31.

[0046] Furthermore, a ring-shaped attraction member (attraction portion) 37 including a magnet is embedded and disposed on the upper surface 33b side of the cover main body 33. An upper surface (surface) 37a of this attraction member 37 is also inclined with respect to the lower surface 33a of the cover main body 33. Specifically, the upper surface 37a is inclined with respect to the lower surface 33a so that the thickness of the attraction member 37 is thicker on the inner peripheral edge 33c side and the outer peripheral edge 33d side of the dirt adhesion prevention cover 31 than on the radial center side of the dirt adhesion prevention cover 31.

[0047] Therefore, ferromagnetic chips and the like generated when grinding the workpiece 11 containing a ferromagnetic material are captured by the magnetic force of the attraction member 37 on the upper surface 33b side of the cover main body 33. Therefore, when this dirt adhesion prevention cover 31 is used, it is possible to prevent dirt from adhering to the frame holding part 10, and also to simplify the process of removing chips containing iron powder and the like from the waste liquid.

[0048] In addition, the structures, methods, etc. according to the above-described embodiments and modifications can be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0049] 1: Dirt prevention cover 3: Cover body (main body) 3a: Bottom surface (first surface) 3b: Top surface (second surface) 3c: Inner edge 3d: outer edge 5: Ferromagnetic material (attachment part) 31: Dirt prevention cover 33: Cover body (main body) 33a: Bottom surface (first surface) 33b: Top surface (second surface) 33c: Inner edge 33d: outer edge 35: Ferromagnetic material (attachment part) 37: Adsorption member (adsorption part) 37a:Top surface (front surface) 2: Grinding equipment (processing equipment) 4: Chuck table 6: Frame 6a: Recess 6b: Flow path 8: Holding plate 8a:Top surface 8b: Vertex 10: Frame holding part 12: Holding unit body 12a:Top surface (support surface) 14: Magnet 20: Grinding unit (processing unit) 22: Spindle 24: Mount 26: Bolt 28: Grinding wheel 30: Wheel base 32: Grinding wheel 11: Workpiece 11a: Surface 11b: Back side 13: Tape 15: Frame 21: Workpiece 21a: Surface 21b: Back side 23: Tape

Claims

1. A dirt adhesion prevention cover attached to a frame holding part of a processing device including: a chuck table having a holding surface for holding a workpiece; a support surface for supporting an annular frame made of a ferromagnetic material and used by being fixed to the peripheral edge of a tape to be attached to the workpiece; a frame holding part having a magnet for fixing the frame supported on the support surface to the support surface by magnetic force; and a processing unit for processing the workpiece held on the chuck table, a main body portion having a first surface large enough to cover the entire support surface; a mounting portion disposed on the first surface side of the main body portion and made of a ferromagnetic material, When the diameter of the workpiece is smaller than the diameter of the holding plate of the chuck table, the tape having a diameter larger than that of the workpiece is attached to the workpiece, the frame is fixed to the peripheral edge of the tape, and the frame is supported by the support surface of the frame holding part. When the diameter of the workpiece is the same as or larger than the diameter of the holding plate, the frame is not used because the tape is not placed on the support surface of the frame holding part, and the dirt adhesion prevention cover is attached to the frame holding part by the magnetic force of the magnet of the frame holding part acting on the attachment part when the first surface faces the support surface, The frame is fixed to the support surface in a manner that the frame is in contact with the tape on the support surface of the frame holding portion covered with the tape, and the dirt-proof cover is characterized in that it prevents dirt from adhering to the support surface of the frame holding portion that is not covered with the tape.

2. The main body has a second surface opposite the first surface, 2. The dirt-repellent cover of claim 1, wherein the second surface is inclined relative to the first surface.

3. The main body has a second surface opposite the first surface, 2. The dirt-preventing cover according to claim 1, wherein an attraction portion having a magnet and capable of attracting ferromagnetic debris is disposed on the second surface side of the main body portion.

Images