Support sheet and transparent plate processing method

Abstract

A support sheet and a method for processing a transparent plate are provided. The support sheet for supporting a workpiece includes at least a transparent sheet having a front surface for supporting the workpiece and a reflective film laminated on the back surface of the transparent sheet. The method for processing the transparent plate includes at least the following steps: a groove forming step in which a cutting tool is positioned on the front surface of the transparent plate (the workpiece) to cut the workpiece, thereby forming a plurality of half-cut grooves that do not reach the back surface; a supporting step in which the front surface of the support sheet is positioned on the front surface of the transparent plate to support the workpiece; and a cutting step in which the cutting tool is positioned on the back surface of the transparent plate to cut areas corresponding to the half-cut grooves formed on the front surface. The cutting step includes a detection step in which the half-cut grooves formed on the front surface are detected from the back surface of the transparent plate, whereby light is diffusely reflected by the reflective film on the side surfaces and bottom surface of the half-cut grooves formed on the front surface, thereby clearly detecting the half-cut grooves formed on the front surface from the back surface.

Description

Technical Field

[0001] The present invention relates to a support sheet for supporting a workpiece and a method for processing a transparent plate using the support sheet. Background Art

[0002] The wafer is divided along predetermined dividing lines, and a plurality of devices such as ICs and LSIs are formed on the front surface. The wafer is divided into individual device chips by a cutting device having a rotatable cutting blade, and is used in electronic devices such as mobile phones and personal computers.

[0003] In addition, the applicant proposed the following technology: after forming a half-cut groove on the front side of the chip with a depth that does not reach the back side, the half-cut groove is detected from the back side by an infrared camera, and the cutting tool is positioned from the back side of the chip to a depth that reaches the half-cut groove and cutting is performed to divide the chip into individual chips (see patent document 1).

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 06-232255

[0005] However, according to the technology described in Patent Document 1, there is the following problem: after forming a half-cut groove on the front side of a workpiece made of a transparent plate such as glass, when one wants to detect the half-cut groove formed on the front side from the back side by using an alignment unit of a camera device, since the workpiece as a whole is transparent, it is impossible to clearly detect the boundary between the area where the half-cut groove is formed and other areas, making it difficult to accurately cut along the half-cut groove from the back side. Summary of the Invention

[0006] The present invention is completed in view of the above situation, and its main technical problem is to provide a supporting sheet and a processing method of a transparent plate using the supporting sheet, which is suitable for forming a half-cut groove on the front side of a workpiece composed of a transparent plate and then detecting the half-cut groove formed on the front side from the back side.

[0007] To solve the above-mentioned main technical problems, the present invention provides a support sheet that supports a workpiece, wherein the support sheet includes at least: a transparent sheet having a front surface that supports the workpiece; and a reflective film laminated on the back surface of the transparent sheet.

[0008] The transparent sheet is preferably a polyolefin sheet or a polyester sheet. In addition, the reflective film is preferably made of an aluminum film or a metallic color coating.

[0009] In addition, according to the present invention, a method for processing a transparent plate is provided, which method for processing a transparent plate includes at least the following steps: a groove forming step, in which a cutting tool is positioned on the front side of the transparent plate to perform cutting, thereby forming a plurality of half-cut grooves that do not reach the back side; a supporting step, in which the front side of the above-mentioned supporting sheet is positioned on the front side of the transparent plate to perform support; and a cutting step, in which the cutting tool is positioned on the back side of the transparent plate to cut the area corresponding to the half-cut grooves formed on the front side, wherein the cutting step includes the following detection step: detecting the half-cut grooves formed on the front side from the back side of the transparent plate.

[0010] In the cutting step, a cutting blade having a width wider or narrower than the half-cut groove formed on the front surface of the transparent plate can be used to form a groove reaching the half-cut groove from the back surface of the transparent plate to thereby separate the transparent plate into multiple chips.

[0011] The support sheet of the present invention is a support sheet that includes at least a transparent sheet having a front surface for supporting a workpiece and a reflective film laminated on the back surface of the transparent sheet. Therefore, by applying the support sheet to a transparent plate processing method that includes at least a cutting step of positioning a cutting tool on the back surface of the transparent plate to cut an area corresponding to a half-cut groove formed on the front surface, the half-cut groove formed on the front surface can be clearly detected in the detection step of detecting the half-cut groove formed on the front surface from the back surface of the transparent plate.

[0012] In addition, the processing method of the transparent plate of the present invention includes at least the following steps: a groove forming step, positioning the cutting tool on the front side of the transparent plate and cutting to form a plurality of half-cut grooves that do not reach the back side; a supporting step, positioning the front side of the above-mentioned supporting sheet on the front side of the transparent plate and supporting it; and a cutting step, positioning the cutting tool on the back side of the transparent plate and cutting the area corresponding to the half-cut groove formed on the front side, and the cutting step includes a detection step of detecting the half-cut groove formed on the front side from the back side of the transparent plate, so that the light reflected by the reflective film is diffusely reflected on the side and bottom surfaces of the half-cut groove formed on the front side, and the half-cut groove formed on the front side can be clearly detected from the back side. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view showing a manner in which a transparent plate is supported by a support unit when the groove forming step of the present embodiment is performed.

[0014] Figure 2 (a) and (b) are perspective views showing an embodiment of the groove forming step.

[0015] Figure 3 1 and 2 are perspective views showing a first method and a second method of forming a support sheet.

[0016] Figure 4(a) and (b) are perspective views showing an embodiment of the supporting step.

[0017] Figure 5 It is a perspective view showing an embodiment of a detection process for detecting a half-cut groove.

[0018] Figure 6 (a) and (b) are perspective views showing an embodiment of a cutting process.

[0019] Figure 7 This is a perspective view of a transparent plate divided into individual chips according to this embodiment.

[0020] 10: Transparent plate; 10a: Front side; 10b: Back side; 12: Support sheet; 20: Cutting device; 22: Chuck table; 24: Adsorption chuck; 26: Fixture; 30: Cutting unit; 32: Spindle unit; 36A, 36B: Cutting tool; 40: Transparent sheet; 50, 52': Reflective film; 55: Nozzle; 60: Tape pasting table; 62: Flat surface; 70: Shooting unit; 80: Control unit; 90: Display unit; 100: Half-cut groove; 110: Splitting groove. DETAILED DESCRIPTION

[0021] Hereinafter, an embodiment of a method for processing a transparent plate according to the present invention will be described in detail with reference to the accompanying drawings, and a support sheet suitable for the method for processing a transparent plate will also be described.

[0022] When implementing the transparent plate processing method of this embodiment, first Figure 1 As shown, a transparent plate 10 is prepared as a workpiece. The transparent plate 10 is a transparent circular plate such as glass. In addition to glass substrates, sapphire, lithium tantalate (LiTaO3), lithium niobate (LiNbO3) and the like can be used as the plate, without particular limitation.

[0023] Once the transparent plate 10 is prepared, it is transported to Figure 1 The cutting device 20 shown (only a portion is shown) is mounted on a chuck table 22 provided on the cutting device 20. The upper surface of the chuck table 22 is formed by a suction chuck 24, which is connected to a suction unit (not shown). The suction chuck 24 is made of porous ceramic with air permeability. In addition, four clamps 26 are arranged at equal intervals along the circumference of the chuck table 22 of this embodiment. These clamps 26 are used to support the annular frame when the workpiece is supported by a support sheet (described later).

[0024] The transparent plate 10 is placed on the chuck table 22 and the suction unit (not shown) is activated, so that the transparent plate 10 is sucked and held on the adsorption chuck 24 of the chuck table 22. Here, the side exposed above the transparent plate 10 sucked and held by the chuck table 22 is referred to as the front side 10a, and the opposite side (the lower side) is referred to as the back side 10b. If the transparent plate 10 is sucked and held on the chuck table 22, a groove forming process is performed, and a cutting tool is positioned on the front side 10a of the transparent plate 10 to cut and form a plurality of half-cut grooves that do not reach the back side 10b. For this groove forming process, refer to Figure 2 Provide more specific explanation.

[0025] like Figure 2 As shown in (a), a cutting unit 30 for performing a groove forming process is provided in the cutting device 20. The cutting unit 30 includes a spindle unit 32. The spindle unit 32 includes: a rotating spindle 34, which is driven to rotate by a motor (not shown); a cutting tool 36A, which is fixed to the front end of the rotating spindle 34 and has a cutting edge on the outer periphery. The cutting tool 36A has a thickness of, for example, 50 μm; and a tool cover 38, which protects the cutting tool 36A. The spindle unit 32 is configured to be movable in the Y-axis direction indicated by the arrow Y and the Z-axis direction indicated by the arrow Z by a moving unit (not shown).

[0026] When the transparent plate 10 is held on the chuck table 22, the cutting tool 36A is positioned at a predetermined machining start position, i.e., a depth position that does not reach the back surface 10b of the transparent plate 10. The cutting tool 36A is rotated at a predetermined rotational speed (e.g., 30,000 rpm), and the moving unit (not shown) is operated to move the chuck table 22 in the X-axis direction indicated by the arrow X, thereby forming a half-cut groove 100 from the front surface 10a side to a depth that does not reach the back surface 10b (see FIG. 1 ). Figure 2 (b)). If the first half-cut groove 100 is formed along the X-axis direction, the main spindle unit 32 is raised in the Z-axis direction by the moving unit not shown, and is moved in the Y-axis direction to form the half-cut groove 100 again at a predetermined interval. By repeating the above process, a plurality of half-cut grooves 100 are formed at a predetermined interval in a predetermined direction on the entire front surface 10a of the transparent plate 10. Then, the rotation drive unit not shown is operated to rotate the chuck table 22 90°, and a plurality of half-cut grooves 100 are formed at a predetermined interval in a direction perpendicular to the plurality of half-cut grooves 100 formed previously by the same steps as above, thereby forming the half-cut grooves 100 in a lattice pattern on the entire front surface 10a (if necessary, refer to Figure 4 (a)). Through the above, the groove forming process is completed.

[0027] After the groove forming step is completed, the supporting step is performed to position the front surface of the supporting sheet on the front surface 10a of the transparent plate 10 for supporting. Figure 3 A support sheet suitable for the transparent plate processing method of this embodiment will be described.

[0028] exist Figure 3 1 and 2 show a diagram (upper part in the figure) for explaining an outline of a first method for forming the support sheet 12 of the present embodiment and a diagram (middle part in the figure) for explaining an outline of a second method for forming the support sheet 12 which is different from the first method.

[0029] First, yes Figure 3 The first method shown in the upper portion of the figure is described below. The support sheet 12 is formed from a transparent sheet 40 for supporting the transparent plate 10 and a reflective film 50 previously formed as a circular film. The transparent sheet 40 is a transparent sheet having light transmittance and flexibility. For example, a polyolefin-based sheet or a polyester-based sheet can be used, which is heated to near its melting temperature to develop adhesive properties. The transparent sheet 40 has a front surface 40a (facing downward in the figure) that supports the workpiece 10 and a back surface 40b on which the reflective film 50 is laminated. The reflective film 50 is made of, for example, a film that effectively reflects light, such as aluminum film (aluminum foil). The reflective film 50 is formed to have the same diameter as the transparent plate 10 or slightly larger. It is positioned on the back surface 40b side of the transparent sheet 40 in the central area 42 shown by the dashed line in the figure, which is surrounded by an outer peripheral area 44. It is heated and pressed by a heating roller (not shown) and affixed to the transparent sheet 40, thereby forming the support sheet 12 shown in the lower portion of the figure. The reflective film 50 is not limited to the aluminum film, and may be, for example, a film made of other metals or a circular paper sheet coated with a metallic color.

[0030] exist Figure 3The middle portion of the figure shows a second method, another method for forming the support sheet 12. In this second method, after preparing the transparent sheet 40, a nozzle 55 for applying a metallic color (gold, silver, etc.) paint 52 is positioned above the central region 42 of the back surface 40b. The metallic color paint 52 is sprayed toward the central region 42, thereby laminating a reflective film 52'. Furthermore, a suitable masking sheet is previously attached to the peripheral region 44 surrounding the central region 42. After the metallic color paint 52 is sprayed onto the central region 42, the masking sheet is removed. This second method also allows the formation of a support sheet 12 having a reflective film 52' that effectively reflects light laminated onto the central region 42 of the back surface 40b of the transparent sheet 40. Furthermore, in this second method, the application of the metallic color paint 52 to the central region 42 is not necessarily limited to spraying the metallic color paint 52 from the nozzle 55; application using a sponge roller or the like is also possible.

[0031] When a polyolefin sheet suitable for thermocompression bonding is used as the transparent sheet 40, it can be selected from any of polyethylene, polypropylene, and polystyrene sheets. Alternatively, when a polyester sheet suitable for thermocompression bonding is used as the transparent sheet 40, it can be selected from polyethylene terephthalate or polyethylene naphthalate. Furthermore, the transparent sheet 40 is not limited to polyolefin or polyester sheets; it can be a conventional dicing tape, such as a polyvinyl chloride (PVC) sheet, coated on its front surface with an adhesive such as a paste.

[0032] The support sheet 12 is prepared in advance, and the support step is performed so that the front surface of the support sheet 12 (the front surface 40a side of the transparent sheet 40) is positioned on the front surface 10a of the transparent plate 10 in which the half-cut groove 100 has been formed in the groove forming step. Figure 4 This supporting step will be described in more detail.

[0033] When implementing this support process, prepare Figure 4 A tape applying table 60 having a flat surface 62 as shown in (a) of FIG. The transparent plate 10, having the half-cut groove 100 formed therein by the groove forming step described above, is placed with its front surface 10a facing upward at the center of the flat surface 62. Furthermore, an annular frame F having an opening Fa of a size capable of accommodating the transparent plate 10 is placed on the flat surface 62 so that the transparent plate 10 is positioned at the center of the opening Fa.

[0034] If the tape is applied on the flat surface 62 of the adhesive table 60, Figure 4The transparent plate 10 and the frame F are placed as shown in (a), and the front side of the supporting sheet 12 (the front side 40a of the transparent sheet 40) is oriented downward, and the area corresponding to the reflective film 50 (52') stacked on the back side (the back side 40b of the transparent sheet 40) is positioned on the transparent plate 10 and placed on the front side 10a of the transparent plate 10, and is pressed using a roller not shown. The supporting sheet 12 is formed to a size slightly larger than the opening Fa of the frame F, and the outer edge of the supporting sheet 12 is adhered to the frame F, and the area of the supporting sheet 12 corresponding to the area stacked with the reflective film 50 (52') is adhered to the front side 10a of the transparent plate 10. The above process completes the support process of supporting the transparent plate 10 on the supporting sheet 12. If the transparent plate 10 is supported on the supporting sheet 12 and the frame F in this way, as shown Figure 4 As shown in (b), the transparent plate 10 is turned upside down (front and back) so that the back surface 10b of the transparent plate 10 is exposed upward.

[0035] After the support process is completed, a cutting process is performed to cut the area corresponding to the half-cut groove 100 formed on the front surface 10a from the back surface 10b of the transparent plate 10. In order to perform the cutting process, the transparent plate 10 is conveyed to the Figure 5 The cutting device 20 shown (only a portion is shown) is placed on a chuck table 22 and held by suction, and a frame F is fixed by a clamp 26 .

[0036] When the transparent plate 10 is held on the chuck table 22, the inspection process is performed as a part of the cutting process, and the half-cut groove 100 is inspected from the back surface 10b side of the transparent plate 10. When the inspection process is performed, the cutting device 20 is used. Figure 5 The imaging unit 70 shown in FIG. The imaging unit 70 includes an imaging element (CCD) (not shown) that irradiates visible light and captures images of the chuck table 22 . The imaging unit 70 is connected to a control unit 80 .

[0037] The control unit 80 is composed of a computer and includes: a central processing unit (CPU) that performs calculations according to a control program; a read-only memory (ROM) that stores the control program, etc.; a read-write random access memory (RAM) that temporarily stores information transmitted from the imaging unit 70, calculation results, etc.; and an input interface and an output interface (details omitted in the figure). A display unit 90 for appropriately displaying processing information, etc. is connected to the output interface of the control unit 80. Information on the half-cut groove 100 detected by the imaging unit 70 is transmitted to the control unit 80. In the control unit 80, the position information of the half-cut groove 100 captured by the imaging unit 70 can be calculated to perform alignment with the cutting tool of the cutting unit 30 described later. The information detected by the imaging unit 70 is appropriately stored in the memory (RAM) of the control unit 80 and displayed on the display unit 90.

[0038] In order to detect the half-cut groove 100 formed on the front surface 10a of the transparent plate 10 using the imaging unit 70, the moving unit (not shown) is operated to position the transparent plate 10 held by the chuck table 22 directly below the imaging unit 70. When the transparent plate 10 is positioned directly below the imaging unit 70, visible light (illumination light) is irradiated from the imaging unit 70 toward the transparent plate 10, and the back surface 10b of the transparent plate 10 is imaged by the imaging element (CCD). As described above, the transparent plate 10 and the transparent sheet 40 constituting the support sheet 12 used in this embodiment are transparent. A reflective film 50 (52') that effectively reflects light is laminated on the central region of the back surface 40b of the transparent sheet 40, i.e., the region supporting the transparent plate 10. As a result, the illumination light irradiated from the imaging unit 70 passes through the transparent plate 10 and the transparent sheet 40, is reflected by the reflective film 50 (52'), and is diffusely reflected on the side and bottom surfaces of the half-cut groove 100 formed on the front surface 10a of the transparent plate 10. Therefore, if you use Figure 5 As shown on the display unit 90, the half-cut groove 100 is displayed on the back surface 10b of the transparent plate 10, and it is possible to accurately grasp the coordinate position of the half-cut groove 100 on the cutting device 20. By performing the detection process in this way, the direction and coordinate position of the half-cut groove 100 are accurately determined and stored in the memory of the control unit 80.

[0039] After the above-mentioned detection process is performed, the chuck table 22 is moved to position the transparent plate 10. Figure 6 (a) is directly below the cutting unit 30. Figure 6The cutting unit 30 shown in (a) is the cutting unit 30 used in the groove forming process. However, in this embodiment, the cutting tool 36A used in the groove forming process is removed and replaced with a cutting tool 36B having a thickness wider than the groove width of the half-cut groove 100, for example, 100 μm. If the transparent plate 10 is positioned directly below the cutting unit 30 as described above, then according to the position information of the half-cut groove 100 stored in the control unit 80, as shown in FIG. Figure 6 As shown in (b), the cutting tool 36B is positioned at the area corresponding to the half-cut groove 100, that is, at the depth of the half-cut groove 100, from the back side 10b of the transparent plate 10. And, while rotating the cutting tool 36B in the direction indicated by the arrow R at a rotation speed of, for example, 30,000 rpm, the chuck table 22 is moved in the X-axis direction, thereby cutting the area corresponding to the half-cut groove 100 formed on the front side 10a to form a dividing groove 110. In this way, the transparent plate 10 is completely divided by the half-cut groove 100 and the dividing groove 110. In addition, the chuck table 22 and the spindle unit 32 are moved relative to each other to form the above-mentioned dividing groove 110 in the area corresponding to all the half-cut grooves 100 formed on the front side 10a of the transparent plate 10. Through the above, the cutting process is completed, as shown in FIG. Figure 7 As shown, the transparent plate 10 is divided into a plurality of chips 10 ′.

[0040] In the cutting process of this embodiment, as described above, the cutting tool 36B having a thickness wider than the groove width of the half-cut groove 100 formed by the cutting tool 36A having a thickness of 50 μm is replaced and cutting is performed, so that Figure 6 As shown in (b), a step difference portion is formed on the side surface of each chip. The step difference portion is formed on the periphery of each chip 10', so that the chip 10' can function as a cover part suitable for closing a recess having a small rectangular opening. In addition, when forming such a step difference portion, it is not necessarily limited to performing the cutting process by using a cutting tool 36B with a thickness wider than the groove width of the half-cut groove 100. For example, by making the thickness of the cutting tool 36A when performing the groove forming process of forming the half-cut groove 100 100μm and making the thickness of the cutting tool 36B when performing the cutting process of cutting the area corresponding to the half-cut groove 100 from the back side 10b side 50μm, although the upper and lower directions are opposite, the same step difference portion as described above can be formed.

Claims

1. A method for processing a transparent plate, wherein: The processing method of the transparent plate comprises at least the following steps: A groove forming step of positioning a cutting tool on the front surface of the transparent plate and cutting the transparent plate to form a plurality of half-cut grooves that do not reach the back surface; a supporting step of positioning a front surface of a supporting sheet corresponding to an area where the reflective film is formed on the front surface of the transparent plate having the half-cut groove formed thereon for supporting the supporting sheet, the supporting sheet comprising a transparent sheet having a front surface for supporting the transparent plate and the reflective film laminated on a rear surface of the transparent sheet; as well as In the cutting step, a cutting tool is positioned on the back side of the transparent plate to cut the area corresponding to the half-cut groove formed on the front side. The cutting step includes an inspection step of inspecting the half-cut groove formed on the front surface of the transparent plate from the back surface before cutting the region corresponding to the half-cut groove.

2. The method for processing a transparent plate according to claim 1, wherein: In the cutting step, a cutting blade having a width wider or narrower than the half-cut groove formed on the front surface of the transparent plate is used to form a groove reaching the half-cut groove from the back surface of the transparent plate to thereby separate the transparent plate into a plurality of chips.

3. The method for processing a transparent plate according to claim 1, wherein: The transparent sheet may be a polyolefin-based sheet or a polyester-based sheet.

4. The method for processing a transparent plate according to claim 2 or 3, wherein: The reflective film includes any material selected from aluminum thin film and metallic color paint.

Images