JP6377513B2 - Sheet-like member - Google Patents

Description

  The present invention relates to a sheet-like member for protecting a wafer device held by a holding surface.

  A technique is known in which a modified layer is formed inside a semiconductor wafer or an optical device wafer, and the wafer is divided into device chips using the modified layer as a breakage starting point. At this time, the laser beam forming the modified layer is permeable to the wafer, but is not permeable to the film formed on the surface of the wafer in many cases. A laser beam may be incident from the back side of a non-wafer.

  The wafer is usually processed by fixing and exposing the surface on which the device is formed on the annular frame via an adhesive tape. This is because the device is used for alignment or the like. For the same reason after laser processing, it is more efficient to expose and fix the device.

  When a laser beam is incident from the back side of the wafer, a processing method is proposed in which the surface on which the device is formed is held by the holding surface of the chuck table and laser processing is performed from the back side of the wafer while allowing the adhesive tape to pass through. Yes. In order to prevent the device from directly contacting the holding surface and being damaged, a processing method for holding the device via the sheet-like member has also been proposed, and a chuck table having means for fixing the sheet-like member has also been proposed ( Patent Document 1).

JP 2013-229403 A

  However, in the chuck table shown in Patent Document 1, due to the increase in flexibility due to the thinning of the sheet-like member, the outer peripheral portion protruding from the holding surface (chuck table) tends to hang down below the holding surface. There existed a subject that it became easy to generate | occur | produce kinking in the area | region which covers a holding surface.

  Further, even if the sheet-like member is subjected to some non-adhesive treatment, it strongly contacts the adhesive tape near the outer edge of the chuck table (the adhesive tape is pulled down by the clamp, Therefore, the adhesive tape sometimes sticks, and the adhesive tape does not peel off after the processing is finished, and the wafer cannot be taken out, causing an operation error.

  The present invention has been made in view of the above, and an object thereof is to provide a sheet-like member capable of reliably carrying out a wafer.

  In order to solve the above-described problems and achieve the object, the sheet-like member of the present invention includes a holding portion having a holding surface for holding a wafer having a device formed on the surface, and a frame body surrounding the holding portion. A sheet-like member that covers the holding surface of the chuck table and that protects the device on the wafer surface facing the holding surface, and is formed of a material having flexibility and air permeability. A main body having a size that covers and reaches the frame, a main body holding area that is intermittently formed on the main body along the periphery of the frame, and that corresponds to the holding surface; and an outer periphery of the main body holding area And a plurality of intermeshing hole portions that divide the main body portion.

  The sheet-like member of the present invention has an effect that the processed wafer can be reliably carried out.

FIG. 1 is a diagram illustrating a sheet-like member according to the embodiment. FIG. 2 is an exploded perspective view showing the chuck table mechanism on which the sheet-like member according to the embodiment is installed. FIG. 3 is a perspective view showing a state in which the chuck table mechanism shown in FIG. 2 holds a wafer or the like. FIG. 4 is a side sectional view showing a state in which laser processing is performed on the wafer held by the chuck table mechanism shown in FIG.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

Embodiment
A sheet-like member according to an embodiment will be described with reference to the drawings. FIG. 1A is a plan view of a sheet-like member according to the embodiment. FIG.1 (b) is sectional drawing which follows the IB-IB line | wire in Fig.1 (a). FIG. 2 is an exploded perspective view showing the chuck table mechanism on which the sheet-like member according to the embodiment is installed. FIG. 3 is a perspective view showing a state in which the chuck table mechanism shown in FIG. 2 holds a wafer or the like. FIG. 4 is a side sectional view showing a state in which laser processing is performed on the wafer held by the chuck table mechanism shown in FIG.

  The sheet-like member 20 according to the present embodiment covers the holding surface 12a of the chuck table 11 shown in FIGS. 2 and 4 and protects the device D on the wafer W surface WS. The wafer W on which the device D is protected is a processing target to be irradiated with the laser beam L by the laser processing apparatus 1 shown in FIG. In the present embodiment, the wafer W is a disk-shaped semiconductor wafer or optical device wafer having silicon, sapphire, gallium or the like as a base material.

  As shown in FIG. 3, the wafer W is formed with devices D in respective regions defined by the division lines S provided on the surface WS in a grid pattern. As shown in FIGS. 3 and 4, the wafer W has a back surface WR on the back side of the surface WS in which a plurality of devices D are formed on the adhesive surface Ta of the adhesive tape T whose outer peripheral edge is attached to the annular frame F. By being attached, it is fixed to the annular frame F. For this reason, the wafer W is fixed to the annular frame F in a state where the surface WS on which a plurality of devices D are formed is exposed. Note that an epi layer (not shown) is formed on the surface WS of the wafer W. The epi layer is made of a material that attenuates or blocks the laser beam L. The adhesive tape T and the adhesive surface Ta are made of a material that transmits the laser beam L.

  A laser processing apparatus 1 that irradiates a wafer W with a laser beam L is an apparatus that forms a modified layer K (shown in FIG. 4) inside the wafer W. The modified layer K means a region where the density, refractive index, mechanical strength and other physical characteristics are different from those of the surroundings, and includes a melt-treated region, a crack region, and a dielectric breakdown region. , A refractive index change region, a region where these regions are mixed, and the like.

  As shown in FIG. 4, the laser processing apparatus 1 irradiates the wafer W held by the chuck table mechanism 10 with the wafer W and a laser beam L having a wavelength of 1064 nm that passes through the wafer W and passes through the wafer W. Laser beam irradiating means 30, X-axis moving means and Y-axis moving means (not shown) for relatively moving the chuck table mechanism 10 and the laser beam irradiating means 30 in the X and Y axis directions parallel to the horizontal direction perpendicular to each other. Etc. at least.

  The chuck table mechanism 10 sucks and holds the wafer W by the holding surface 12a. 2 and 3, the chuck table mechanism 10 includes a chuck table 11 that sucks and holds the surface WS of the wafer W with a holding surface 12a, and an annular fixing portion 15 that is detachably fastened to the chuck table 11. It is comprised including.

  The chuck table 11 holds the wafer W that has been bonded to the opening of the annular frame F by placing the wafer W before laser processing on the holding surface 12a. The chuck table 11 includes a holding portion 12 having a holding surface 12 a for sucking and holding the wafer W, and a frame body 13 surrounding the holding portion 12. That is, the chuck table 11 has a holding surface 12a. The holding unit 12 has a disk shape formed of a porous material such as porous ceramic, and is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown) to suck the wafer W placed on the holding surface 12a. Hold by. The frame 13 is made of a metal such as stainless steel and is formed in an annular shape.

  The chuck table 11 is processed and fed in the X-axis direction by the X-axis moving means, rotated around the central axis by a rotation drive source (not shown), and indexed and fed in the Y-axis direction by the Y-axis moving means. . Further, around the chuck table 11, there are provided a plurality of clamp portions 14 that are driven by an air actuator and sandwich the annular frame F around the wafer W.

  The annular fixing portion 15 is made of a metal such as stainless steel and is formed in an annular shape. The annular fixing portion 15 is fitted to the outer periphery of the frame body 13 of the chuck table 11, and the outer peripheral portion 24 that protrudes from the outer edge of the frame body 13 of the chuck table 11 of the sheet-like member 20 that covers the holding surface 12 a. Between the outer peripheral surface and the holding surface 12a.

  The sheet-like member 20 that covers the holding surface 12a of the chuck table 11 and is attached to the chuck table mechanism 10 protects the device D on the wafer W surface WS that faces the holding surface 12a. The sheet-like member 20 is a porous film made of a synthetic resin such as ultrahigh molecular weight polyethylene, and is formed of a material having flexibility, air permeability, and releasability. The sheet-like member 20 has a circular shape with a diameter larger than that of the holding surface 12 a of the holding unit 12. In the present embodiment, the sheet-like member 20 has a diameter of 340 mm and a thickness of about 0.1 mm to 0.4 mm, for example, about 0.2 mm.

  As shown in FIGS. 1A and 1B, the sheet-like member 20 covers the holding surface 12 a of the holding portion 12 and has a main body portion 21 having a size reaching the frame body 13 and a plurality of intermittent hole portions. 22. The diameter of the main body portion 21 is formed larger than the outer diameter of the frame body 13, that is, the outer diameter of the chuck table 11. The intermittent hole portion 22 is formed intermittently on the main body portion 21 along the peripheral edge (outer edge) of the frame body 13, and the main body holding region 23 corresponding to the holding surface 12 a and the outer periphery of the outer periphery of the main body holding region 23. The main body 21 is separated from the part 24. The intermittent hole portion 22 is a hole opened in the main body portion 21, and the planar shape is formed in an arc shape with the center of the main body portion 21 as the center of curvature, and is spaced at equal intervals in the circumferential direction of the main body portion 21. Has been placed.

  When the sheet-like member 20 covers the chuck table 11 of the chuck table mechanism 10, the main body holding region 23 of the main body 21 divided by the intermittent hole 22 overlaps the holding surface 12 a and the upper surface of the frame 13. When the sheet-like member 20 covers the chuck table 11 of the chuck table mechanism 10, the outer peripheral portion 24 of the main body portion 21 overlaps with the outer peripheral surface of the frame body 13, and the annular fixing portion 15 is fitted to the outer periphery. Is sandwiched between the outer peripheral surface of the ring and the annular fixing portion 15. For this reason, when the sheet-like member 20 covers the chuck table 11 of the chuck table mechanism 10, the intermittent hole portion 22 overlaps with the corner portion 13 a of the frame 13. In the present embodiment, the width of the outer peripheral portion 24 of the sheet-like member 20 is formed to be about 20 mm.

  A method for installing the sheet-like member 20 on the chuck table mechanism 10 having the above-described configuration will be described. In a state where the annular fixing portion 15 is not fitted, the main body holding region 23 of the sheet-like member 20 is overlapped on the holding surface 12 a of the chuck table 11, and the intermittent hole portion 22 is formed at the corner portion 13 a of the frame 13 of the chuck table 11. Overlay on. Then, while pressing the outer peripheral portion 24 of the sheet-like member 20 against the outer peripheral surface of the frame body 13 of the chuck table 11, the annular fixing portion 15 is fitted to the outer periphery of the frame body 13 of the chuck table 11. Since the intermittent hole portion 22 of the sheet-like member 20 overlaps the corner portion 13a of the frame body 13 of the chuck table 11, the sheet-like member 20 is reliably bent at the corner portion 13a of the frame body 13 of the chuck table 11, The main body holding region 23 can be brought into close contact with the holding surface 12a.

  The laser processing apparatus 1 including the chuck table mechanism 10 having the above-described configuration sucks and holds the surface WS of the wafer W on the holding surface 12a of the holding unit 12 of the chuck table 11 via the sheet-like member 20, and The annular frame F is clamped by the clamp portion 14. Then, the adhesive surface Ta of the adhesive tape T mainly faces the sheet-like member 20 on the corner 13 a of the frame 13. Then, the laser processing apparatus 1 relatively moves the wafer W held on the chuck table mechanism 10 and the laser beam irradiation means 30 along the scheduled division line S by the X-axis moving means, the Y-axis moving means, and the rotational drive source. The modified layer K is formed on the division line S by irradiating the laser beam L from the laser beam irradiation means 30 toward the back surface WR of the wafer W. When the modified layer K is formed on all the division lines S, the irradiation of the laser beam L from the laser beam irradiation means 30 is stopped. Then, the wafer W on which the modified layer K is formed is transported to the next process or the like and then divided into device chips with the modified layer K as a base point.

  As described above, according to the sheet-like member 20 according to the present embodiment, the intermittent hole portion 22 that opens intermittently in the main body portion 21 along the peripheral edge of the frame body 13 overlaps the corner portion 13 a of the frame body 13. For this reason, as for the sheet-like member 20, the intermittent hole part 22 will reduce a contact area with the adhesive tape T. FIG. Therefore, the sheet-like member 20 can reduce the possibility that the adhesive tape T sticks, can prevent the adhesive tape T from being peeled off at the end of laser processing, and reliably carry out the wafer W after laser processing. be able to.

  Further, according to the sheet-like member 20, the intermittent hole portion 22 that is intermittently opened in the main body portion 21 overlaps with the corner portion 13 a of the frame body 13, so that it can be reliably bent at the corner portion 13 a of the frame body 13. The main body holding region 23 can be brought into close contact with the holding surface 12a, and the outer peripheral portion 24 can be put in close contact with the outer peripheral surface of the frame body 13. Therefore, the sheet-like member 20 minimizes the influence on the main body holding region 23 that covers the holding surface 12a when the outer peripheral portion 24 hangs down from the holding surface 12a and extends along the outer peripheral surface of the frame 13. The flat state can be maintained without the main body holding region 23 covering the holding surface 12a being swung. Therefore, the sheet-like member 20 can be easily fixed to the chuck table mechanism 10.

  The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 11 Chuck table 12 Holding part 12a Holding surface 13 Frame body 20 Sheet-like member 21 Main body part 22 Intermittent hole part 23 Main body part holding | maintenance area | region 24 Outer peripheral part W Wafer WS Surface D Device

Claims (1)

The device on the wafer surface that covers the holding surface of the chuck table including a holding portion having a holding surface for holding the wafer on which the device is formed, and a frame body surrounding the holding portion, and faces the holding surface A sheet-like member for protecting
A main body portion formed of a material having flexibility and air permeability, covering the holding surface, and sized to reach the frame;
A plurality of intermittent holes that are intermittently formed in the main body along the periphery of the frame, and divide the main body into a main body holding area corresponding to the holding surface and an outer peripheral portion of the outer periphery of the main body holding area. And
A sheet-like member comprising:

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