JP2016016502A - Grinding device, protective tape adhesion method, and protective tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding device which adheres a protective tape to a wafer without causing compression of an installation area in a factory and degradation of productivity, and provide a protective tape adhesion method and a protective tape.SOLUTION: A grinding device 1 includes at least: a chuck table 3 having a suction surface for holding a first surface of a wafer; and grinding means 4a, 4b which grind a second surface held by the chuck table, and includes at least: protective tape conveying means 7 which mounts a rear surface of the protective tape on the suction surface of the chuck table in which the protective tape has air permeability from a front surface to a rear surface, includes an adhesive layer on a front surface, and has an approximately same outer shape as the wafer; wafer conveying means 64 which mounts the first surface of the wafer on the adhesive layer of the protective tape mounted on the suction surface; and suction force generating means which sucks the first surface of the wafer through the protective tape and adheres the first surface of the wafer to the adhesive layer of the protective tape. The protective tape is adhered on the wafer without using a protective tape adhesion device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a grinding apparatus capable of attaching a protective tape to a wafer to be ground, a protective tape attaching method for attaching a protective tape to a wafer, and a protective tape to be attached to a wafer.

  A wafer on which a plurality of devices such as IC, LSI, etc. are partitioned by lines to be divided and formed on the front surface is formed into a predetermined thickness by forming a back surface by a grinding device, and then divided into individual devices by a dicing device or the like. It is divided and used for various electronic devices.

  The grinding apparatus includes a chuck table for sucking and holding a wafer, a grinding unit having a rotatable grinding wheel, and a grinding feed unit for grinding and feeding the grinding unit relative to the chuck table, and rotates. The wafer can be ground to a desired thickness by abutting the grinding wheel against the back surface of the wafer sucked and held by the chuck table and grinding.

  At the time of grinding the back surface of the wafer, a protective tape is attached to the surface of the wafer in order to prevent damage to the device formed on the surface of the wafer. A protective tape sticking device is used for sticking the protective tape to the surface of the wafer (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 61-25769 JP-A-62-230561

  However, since the protective tape sticking device is installed adjacent to the grinding device separately from the grinding device, there is a problem of pressing the installation space of the factory. Moreover, since it is necessary to perform the process of sticking a protective tape on the surface of a wafer before the grinding process of grinding a wafer, there also exists a problem of reducing productivity. Such a problem occurs not only when a protective tape is attached to a wafer to be ground, but also when a protective tape is attached to a wafer to be processed.

  The present invention has been considered in view of such problems, and it is an object of the present invention to attach a protective tape to a wafer without reducing the installation area in the factory and without reducing the productivity.

A first invention is a grinding apparatus comprising at least a chuck table having a suction surface for holding a first surface of a wafer, and a grinding means for grinding a second surface held by the chuck table. A protective tape transport means for placing the back surface of the protective tape on the suction surface of the chuck table, which has air permeability from the back surface to the back surface and has an adhesive layer on the front surface and has an outer shape substantially the same shape as the wafer; Wafer transfer means for placing the first surface of the wafer on the adhesive layer of the protective tape, and an adhesive layer of the protective tape by attracting the first surface of the wafer via the protective tape by applying a suction force to the suction surface And at least suction force generating means for adhering the first surface of the wafer.
It is preferable that a release paper is attached to the adhesive layer of the protective tape, and a plurality of pores that generate air permeability are formed from the release paper to the back surface of the protective tape.
In addition, the grinding apparatus is provided with protective tape stock means for stacking and storing a plurality of protective tapes, and peeling means for peeling the release paper from the adhesive layer of the protective tape placed on the suction surface of the chuck table. The protective tape conveying means preferably conveys the protective tape from the protective tape stock means to the suction surface of the chuck table.

  The second invention is a protective tape attaching method for attaching a protective tape to a first surface of a wafer having a first surface and a second surface, wherein the surface has air permeability from the front surface to the back surface. A protective tape placing step for placing the back surface of the protective tape having an outer shape substantially the same shape as the wafer on the suction surface of the chuck table, and an adhesive layer of the protective tape placed on the suction surface. A wafer transfer step for placing the first surface, and a suction force is applied to the suction surface, the first surface of the wafer is sucked through the protective tape, and the first surface of the wafer is applied to the adhesive layer of the protective tape. A suction step for attaching.

The third invention is a protective tape, comprising at least a sheet, an adhesive layer laid on the surface of the sheet, and a plurality of pores that penetrate the sheet and the adhesive layer to cause air permeability .
It is preferable that release paper is attached to the adhesive layer, and the release paper has a plurality of pores corresponding to the pores formed in the adhesive layer.

  The grinding apparatus according to the present invention is a protective tape transport that has air permeability from the front surface to the back surface, has an adhesive layer on the surface, and places the back surface of the protective tape having an outer diameter substantially the same shape as the wafer on the suction surface of the chuck table. Means, wafer transport means for placing the first surface of the wafer on the adhesive layer of the protective tape placed on the suction surface, and the first surface of the wafer via the protective tape by applying a suction force to the suction surface And suction force generating means for sticking the first surface of the wafer to the adhesive layer of the protective tape to stick the protective tape to the wafer without using a protective tape sticking device Therefore, the part occupied by the protective tape attaching device in the factory installation area can be opened. Further, since the protective tape can be attached to the first surface of the wafer to be ground next by using the waiting time while grinding another wafer, the productivity is improved.

  The protective tape attaching method according to the present invention is such that the back side of the breathable protective tape is placed on the suction surface of the chuck table, and the first surface of the wafer is placed on the adhesive layer of the protective tape placed on the suction surface. Is applied to the suction surface, the first surface of the wafer is sucked through the protective tape and the first surface of the wafer is adhered to the adhesive layer of the protective tape. A protective tape can be attached to the wafer without using a deposition apparatus. Therefore, the part which the protective tape sticking apparatus occupied in the installation area of a factory can be open | released.

  The protective tape according to the present invention is composed of a sheet, an adhesive layer laid on the surface of the sheet, and a plurality of pores that penetrate the sheet and the adhesive layer and have air permeability. It can be used for a tape sticking method.

It is a perspective view which shows the example of a grinding device. It is a perspective view which shows the example of a chuck table. It is a perspective view which shows the example of a wafer. It is a perspective view which shows the example of a protection tape stock means. It is sectional drawing which shows the example of a protective tape. It is a perspective view which shows the example of a release paper discarding means. It is a perspective view which shows the state which conveys a protection tape. It is a perspective view which shows a protection tape mounting step. It is a perspective view which shows a wafer conveyance step. It is a perspective view which shows the state by which the wafer was stuck to the protective tape. It is a perspective view which shows a grinding step.

1 Configuration of Grinding Apparatus A grinding apparatus 1 shown in FIG. 1 is an apparatus for grinding various wafers such as semiconductor wafers to a predetermined thickness. The grinding apparatus 1 includes a processing region 11 (+ Y direction side) for grinding a wafer, and a delivery region 12 (−) that supplies a wafer before grinding to the processing region 11 and receives the ground wafer from the processing region 11. (Y direction side).

  The processing area 11 includes a rotatable turntable 2, a plurality of chuck tables 3 disposed on the turntable 2, grinding means 4 a and 4 b for grinding a wafer held on the chuck table 3, and a grinding means 4 a. Grinding feeding means 5a and 5b for grinding and feeding 4b in the Z-axis direction are provided.

  The chuck table 3 can rotate and can revolve by the rotation of the turntable 2. As shown in FIG. 2, the chuck table 3 includes a disk-like suction plate 30 formed of porous ceramics and the like, and a frame body 31 surrounding the suction plate 30. A wafer is placed on the suction surface 33 which is the surface of the suction plate 30. Connected to the suction plate 30 is a suction source 33 that is a suction force generating means for applying a suction force to the suction surface 33.

  The grinding means 4a, 4b shown in FIG. 1 includes a spindle 40 having an axis in the Z-axis direction, a motor 41 for rotating the spindle 40, a mount 42 attached to the lower end of the spindle 40, and a mount 42. And a grinding wheel 43. A plurality of grinding wheels 44 are fixed to the lower surface of the grinding wheel 43 in an annular shape. The grinding wheel 44 constituting the grinding means 4a is a rough grinding wheel, and the grinding wheel constituting the grinding means 4b is a grinding wheel for finish grinding.

  The grinding feed means 5a and 5b include a ball screw 50 having an axis in the Z-axis direction, a pulse motor 51 that rotates the ball screw 50, a pair of guide rails 52 arranged in parallel to the ball screw 50, and the rotation of the ball screw 50. It is comprised from the raising / lowering board 53 which is guided by the guide rail 52 and raises / lowers. Grinding means 4a and 4b are fixed to the elevating plate 53, respectively, and as the elevating plate 53 is raised and lowered by the rotation of the ball screw 50, the grinding means 4a and 4b are also raised and lowered.

  The delivery area 12 includes cassette mounting areas 6a and 6b on which a cassette 60a for storing a wafer before grinding and a cassette 60b for storing a wafer after grinding are respectively mounted. As shown in FIG. 3, the wafer W accommodated in the cassette 60a is formed in a substantially circular shape, and a plurality of devices D are formed on the surface (first surface) W1 by being partitioned by the division lines L. Has been. Further, the opposite surface of the front surface W1 is a back surface (second surface) W2 where no device is formed. A notch N, which is a mark for identifying the crystal orientation, is formed in the peripheral portion of the wafer W so as to be recessed toward the center of the wafer W.

  As shown in FIG. 1, between the cassette 60a and the cassette 60b, a loading / unloading means 61 for loading the wafer W before grinding from the cassette 60a and loading the wafer W after grinding into the cassette 60b is provided. Yes. The carry-in / out means 61 includes an arm portion 610 that can be bent and lifted and a holding portion 611 that is attached to the tip of the arm portion 610 and holds the wafer W by suction. In the movable range of the holding unit 611, a temporary placement table 62 that aligns the wafer W at a certain position and a cleaning unit 63 that cleans the wafer W after grinding are disposed. The cleaning means 63 includes a spinner table 630 that holds and rotates the wafer W to be cleaned, and a nozzle (not shown) that jets cleaning liquid and high-pressure air to the wafer W held on the spinner table 630.

  In the vicinity of the temporary placement table 62, wafer transport means 64 for transporting the unground wafer W from the temporary placement table 62 to the chuck table 3 located in the delivery area 12 is disposed. Adjacent to the wafer transfer means 64, a transfer means 65 for transferring the ground wafer W from the chuck table 3 to the cleaning means 63 is provided. The wafer transfer unit 64 includes a holding unit 640 that holds the wafer W, and an arm unit 641 that moves the holding unit 640 in the horizontal direction and the vertical direction. Similarly, the transfer means 65 includes an arm portion 651 that moves the holding portion 650 in the horizontal direction and the vertical direction.

  Above the chuck table 3 located in the delivery area 12, a protective tape transport means 7 for transporting the protective tape to be attached to the wafer W is disposed. The protective tape transport means 7 includes a rail 70 installed so as to cross over the turntable 2 in the X-axis direction, a moving unit 71 that moves in the X-axis direction along the rail 70, and a moving unit 71 The holding part 72 which can be moved up and down is provided. The holding unit 72 includes a suction plate at the lower end for sucking and holding the wafer.

  A protective tape stock means 8 is disposed in the vicinity of one end of the rail 70 constituting the protective tape conveying means 7, and a release paper discarding means 9 is disposed in the vicinity of the other end. As shown in FIG. 4, the protective tape stock means 8 is formed in a cylindrical shape capable of storing a plurality of protective tapes 100 in a stacked manner.

  The protective tape 100 is a tape that is attached to the surface W1 of the wafer W shown in FIG. 3 and protects the device D. As shown in FIG. 5, the adhesive is laid on the sheet 101 and the surface 101a of the sheet 101. Layer 102. The back surface 101 b of the sheet 101 is exposed, and this back surface 101 b is the back surface of the protective tape 100. In the sheet 101 and the adhesive layer 102, a plurality of pores 104 penetrating in the thickness direction are formed and have air permeability. The pores 104 can be formed, for example, by irradiating laser light in the thickness direction of the protective tape 100. The diameter of each pore 104 is, for example, 0.1 mm, and the interval P between adjacent pores 104 is, for example, about 5 mm. This interval is preferably constant. In addition, the thing of the raw material in which the hole which penetrates front and back was formed in mesh shape can also be utilized as the protective tape 100, for example.

  A release paper 103 is attached to the adhesive layer 102. The release paper 103 also has a plurality of pores 105 penetrating in the thickness direction at positions corresponding to the pores 104 formed in the sheet 101 and the adhesive layer 102, that is, at positions facing the pores 104. The protective tape 100 and the release paper 103 as a whole have air permeability in the thickness direction from the front surface (exposed surface of the release paper 103) to the back surface (the back surface 101b of the sheet 101). The protective tape 100 and the release paper 103 are formed in a substantially circular shape that is substantially the same shape as the wafer W in correspondence with the wafer W shown in FIG. Note that the protective tape 100 may not have a recess corresponding to the notch N formed in the wafer W. Further, when the wafer is formed in a rectangular shape, for example, the protective tape is also formed in a rectangular shape.

  As shown in FIG. 6, the release paper discarding means 9 is formed in a cylindrical shape that can accommodate a plurality of used release papers 103 peeled from the adhesive layer 102 shown in FIG.

2 Operation of Grinding Device Hereinafter, the operation of the grinding device 1 when the protective tape 100 shown in FIG. 5 is adhered to the front surface W1 of the wafer W shown in FIG. 3 and the back surface W2 of the wafer W is ground will be described. .

(1) Protection Tape Placement Step First, the moving part 71 of the protective tape conveying means 7 shown in FIG. 1 moves in the + X direction, and the holding part 72 is moved above the protective tape stock means 8. Then, the holding unit 72 descends, and the holding unit 72 sucks the release paper 103 of the protective tape 100 as shown in FIG. In this state, the holding unit 72 is raised, the moving unit 71 is moved in the −X direction, and the protective tape 100 is positioned above the chuck table 3 located in the delivery area 12. Next, the holding portion 72 is lowered, and the back surface of the protective tape 100 (the back surface 101 b of the sheet 101) is placed on the suction surface 33 of the chuck table 3.

  After the back surface of the protective tape 100 is thus placed on the suction surface 33, a suction force is applied to the suction surface 33 from the suction source 32 shown in FIG. In the state where the air is being sucked, the holding portion 72 is rotated, for example, about several degrees in the direction of arrow A, for example, and the slack 106 is generated on the release paper 103 as shown in FIG. Then, by raising the holding portion 72, the release paper 103 is peeled from the adhesive layer 102, and the adhesive layer 102 is exposed. The pores 105 of the release paper 103 are formed at positions corresponding to the pores 104 of the protective tape 100, and the pores 104 are open to the atmosphere via the pores 105. Even if force is applied, the pore 104 does not become negative pressure. Therefore, the release paper 103 is not sucked by the suction force acting on the suction surface 33, and only the protective tape 100 is sucked. Therefore, when the holding unit 72 sucks the release paper 103 and rises, only the release paper 103 rises, so that the release paper 103 can be smoothly peeled from the adhesive layer 102. Further, by forming a slack 106 in advance and forming a gap between the release paper 103 and the adhesive layer 102, the release paper 103 can be more easily peeled from the adhesive layer 102. As described above, the protective tape transport unit 7 also has a function as a peeling unit that peels the release paper 103 from the adhesive layer 102 of the protective tape 100.

  The holding unit 72 that holds the release paper 103 moves in the −X direction and is positioned above the release paper discarding unit 9 shown in FIG. 6. Then, the holding part 72 is lowered and the suction by the holding part 72 is released, whereby the used release paper 103 is accommodated in the release paper discarding means 9.

(2) Wafer Transport Step On the other hand, the cassette carry-in / out means 61 shown in FIG. 1 carries out the wafer W before grinding from the cassette 60 a and transports it to the temporary placement table 62. Then, the wafer W is aligned at a predetermined position on the temporary placement table 62.

  Next, the holding unit 640 of the wafer transport unit 64 holds the back surface W <b> 2 side of the wafer W placed on the temporary placement table 62. Then, the arm portion 641 is raised and swiveled, the wafer W is positioned above the protective tape 100 placed on the suction surface 33 of the chuck table 3 located in the delivery area 12, and the arm portion 641 is lowered, The surface W 1 side of the wafer W is placed on the adhesive layer 102 of the protective tape 100. Thus, when the surface W1 side of the wafer W is placed on the adhesive layer 102, the holding unit 640 lifts and retracts after releasing the suction force.

(3) Suction Step Next, the suction source 33 shown in FIG. 2 applies a suction force to the suction surface 33 of the chuck table 3 on which the protective tape 100 and the wafer W are placed. Since the protective tape 100 has pores 104 and is air permeable from the back surface of the protective tape 100 to the upper surface of the adhesive layer 102, the protective tape 100 is attached to the suction surface 33 by applying a suction force. The surface W1 of the wafer W can be sucked through, and thereby the surface W1 of the wafer W can be adhered to the adhesive layer 102 of the protective tape 100. As shown in FIG. 10, in the state where the front surface W1 of the wafer W is adhered to the adhesive layer 102 of the protective tape 100, the rear surface W2 of the wafer W is exposed.

(4) Grinding Step Next, the turntable 2 is rotated by a predetermined angle (120 degrees in the example of FIG. 1) to move the wafer W having the protective tape 100 adhered to the surface W1 below the grinding means 4a. . Then, as shown in FIG. 11, while the chuck table 3 is rotated in the direction of arrow B at a rotational speed of, for example, 300 rpm, the grinding feed means 5a performs grinding while rotating the grinding wheel 43 in the direction of arrow C at a rotational speed of, for example, 6000 rpm. The means 4a is lowered, and the rotating grinding wheel 44 for rough grinding is brought into contact with the back surface W2 of the wafer W to roughly grind the back surface W2.

  When the back surface W2 of the wafer W is roughly ground by a predetermined amount, the turntable 2 rotates by a predetermined angle (120 degrees) to grind the wafer W on which the protective tape 100 is adhered to the front surface W1 and the back surface W2 is rough ground. It is moved below the means 4b. Then, the grinding feed means 5a lowers the grinding means 4a while rotating the grinding wheel 43, and the rotating grinding wheel 44 for finish grinding is brought into contact with the back surface W2 of the wafer W to finish-grind the back surface W2. When it is formed to a predetermined thickness, the grinding is finished.

  While the rough grinding and finishing processes are performed in this manner, the above-described protective tape placing step, wafer transporting step, and suction step are performed on the wafer W to be ground next. Compared with the time required for each grinding per wafer, the time required for the protective tape placement step, the wafer transfer step and the suction step is short, so use the waiting time while grinding other wafers W. Then, a protective tape can be attached to the surface W1 of the wafer W to be ground next, and the productivity is improved.

(5) Cleaning Step Next, the turntable 2 shown in FIG. 1 rotates by a predetermined angle (120 degrees), so that the wafer W that is finish-ground and sucked and held on the chuck table 3 returns to the delivery area 12. Then, the arm portion 651 of the transfer means 65 is swung and lowered to suck and hold the back surface W2 of the wafer W, and the arm portion 651 is lifted and swung to move the wafer W above the spinner table 630 of the cleaning means 63. After that, the arm unit 651 is lowered and the wafer W is placed on the spinner table 630. Next, a suction force is applied to the spinner table 630 to suck and hold the protective tape 100 adhered to the surface W1 of the wafer W, and the suction by the holding portion 650 of the transfer means 65 is released.

  Then, as the spinner table 630 rotates, a cleaning liquid is ejected from a nozzle (not shown) toward the back surface W2 of the wafer W to remove grinding debris. After that, the spinner table 630 rotates and high-pressure air is jetted toward the back surface W2 of the wafer W to remove the cleaning liquid.

(6) Storage Step The wafer W whose back surface W2 has been cleaned is stored in the cassette 60b by holding the protective tape 100 side by the holding unit 611 of the loading / unloading means 61 and turning and raising / lowering the arm unit 610.

  As described above, in the grinding apparatus 1, since the protective tape 100 can be attached to the wafer W without using the protective tape attaching apparatus, the protective tape attaching apparatus occupies the factory installation area. The part that had been released can be released.

  In the present embodiment, three chuck tables 3 are arranged in the example of FIG. 1, but may be one or two, or four or more. When only one chuck table 3 is provided, the turntable 2 is not necessary. In this case, one chuck table is linearly arranged in the ± Y direction between the delivery area 12 and the machining area 11. What is necessary is just to have the mechanism to move.

  In the present embodiment, the protective tape transport unit 7 serves as a peeling unit that peels the release paper 103 from the protective tape 100. However, the protective tape transport unit 7 may include a peeling unit separately from the protective tape transport unit 7. However, it is preferable that the protective tape transport unit 7 also serves as a peeling unit because the apparatus configuration can be made compact.

  In this embodiment, the release paper 103 is attached to the adhesive layer 102 of the protective tape 100, and the surface W1 of the wafer W is attached to the adhesive layer 102 after the release paper 103 is peeled off. When the back surface 101b of the sheet 101 constituting the sheet has a function equivalent to that of the release paper, the release paper 103 is not necessary.

  Although the grinding apparatus has been described in the present embodiment, the present invention can be applied to a processing apparatus other than the grinding apparatus as long as the apparatus performs processing by attaching a protective tape to one surface of the wafer.

1: Grinding device 11: Processing area 12: Delivery area 2: Turntable 3: Chuck table 30: Suction plate 31: Frame body 32: Suction source 33: Suction surface 4a, 4b: Grinding means 40: Spindle 41: Motor 42: Mount 43: Grinding wheel 44: Grinding wheel 5a, 5b: Grinding feed means 50: Ball screw 51: Pulse motor 52: Guide rail 53: Elevating plate 6a, 6b: Cassette placement area 60a, 60b: Cassette 61: Loading / unloading means 610 : Arm part 611: Holding part 62: Temporary placement table 63: Cleaning means 630: Spinner table 64: Wafer transfer means 640: Holding part 641: Arm part 65: Transfer means 650: Holding part 651: Arm part 7: Protection tape transfer Means 70: Rail 71: Moving part 72: Holding part 8: Protective tape stock means 9: Release paper discarding means W: Wafer W1: Front surface W2: Back surface L: Line to be divided D: Device N: Notch 100: Protection tape 101: Sheet 101a: Front surface 101b: Back surface 102: Adhesive layer 104: Pore 103: Peeling Paper 105: Pore 106: Slack

Claims (6)

A grinding apparatus comprising at least a chuck table having a suction surface for holding a first surface of a wafer and a grinding means for grinding a second surface held by the chuck table,
A protective tape transport means for placing the back surface of the protective tape on the suction surface of the chuck table, which has air permeability from the front surface to the back surface and has an adhesive layer on the surface and has an outer shape substantially the same shape as the wafer;
Wafer transfer means for placing the first surface of the wafer on the adhesive layer of the protective tape placed on the suction surface;
A suction force generating means for applying a suction force to the suction surface, sucking the first surface of the wafer through the protective tape, and sticking the first surface of the wafer to the adhesive layer of the protective tape;
A grinding apparatus provided with at least.   2. The grinding apparatus according to claim 1, wherein a release paper is attached to the adhesive layer of the protective tape, and a plurality of pores that generate air permeability are formed from the release paper to the back surface of the protective tape. Protective tape stock means for storing and storing a plurality of protective tapes;
A peeling means for peeling the release paper from the adhesive layer of the protective tape placed on the suction surface of the chuck table; and
The grinding apparatus according to claim 2, wherein the protective tape conveying means conveys the protective tape from the protective tape stock means to the suction surface of the chuck table. A protective tape attaching method for attaching a protective tape to the first surface of a wafer having a first surface and a second surface,
A protective tape mounting step for mounting the back surface of the protective tape having air permeability from the front surface to the back surface and having an adhesive layer on the surface and having an outer shape substantially the same shape as the wafer on the suction surface of the chuck table;
A wafer transfer step of placing the first surface of the wafer on the adhesive layer of the protective tape placed on the suction surface;
A suction step in which a suction force is applied to the suction surface, the first surface of the wafer is sucked through the protective tape, and the first surface of the wafer is adhered to the adhesive layer of the protective tape;
A method for attaching a protective tape comprising at least Protective tape,
A sheet and an adhesive layer laid on the surface of the sheet;
A plurality of pores that pass through the sheet and the adhesive layer to create air permeability;
Protective tape composed of at least.   6. The protective tape according to claim 5, wherein a release paper is attached to the adhesive layer, and the release paper has a plurality of pores corresponding to the pores formed in the adhesive layer.

Images