Method for processing a workpiece

Abstract

The present application provides a method for processing a workpiece, which processes a workpiece including a substrate and a ductile material layer using a simple process and suppresses burr generation from the ductile material layer. The method is used when processing a workpiece having a substrate with a front surface and a back surface and a ductile material layer including a ductile material having ductility and provided on the front surface or the back surface of the substrate, and includes a tape attaching step of attaching a tape to the substrate side of the workpiece, a holding step of holding the workpiece with a holding table through the tape in a manner that the ductile material layer is exposed, and a cutting step of moving the holding table and a cutting tool relative to each other, cutting the workpiece with the cutting tool into the ductile material layer and the substrate, and rotating the cutting tool in a manner that a portion of the cutting tool located on a front side of the cutting tool with respect to a moving direction of the holding table cuts into the ductile material layer toward the substrate.

Description

Technical Field

[0001] The present invention relates to a method for processing a workpiece that includes a substrate and a layer of ductile material. Background Technology

[0002] In electronic devices such as mobile phones and personal computers, device chips containing electronic circuits and other components are essential building blocks. For example, a wafer made of semiconductor materials such as silicon is divided into multiple regions according to predetermined dividing lines (spacers). After devices are formed in each region, the wafer is divided according to the predetermined dividing lines to obtain a device chip.

[0003] In recent years, to achieve the various functions required by device chips, there has been an increasing opportunity to deposit a film (hereinafter referred to as a metal film) made of metal such as copper on the back side of a wafer. When dicing such a workpiece containing a wafer and a metal film, for example, a strip is attached to the metal film side of the workpiece, and the metal film side (strip) of the workpiece is held in a manner that exposes the wafer. Then, by cutting the workpiece with a cutting tool that rotates upwards from the wafer side towards the metal film side, the workpiece can be cut and diced into multiple device chips.

[0004] However, in the above method, the metal film formed from a malleable metal is stretched towards the strip side by the rotating cutting tool, easily generating metal protrusions called burrs from the metal film. Burrs can cause defects such as short circuits between terminals when mounting device chips onto a printed circuit board. Therefore, it is necessary to sufficiently suppress the generation of burrs when slitting workpieces containing metal films.

[0005] To address this issue, a method for cutting a metal film by irradiating it with a laser beam has been proposed (see, for example, Patent Document 1). In this method, after cutting the workpiece from the wafer side under the condition that the cutting tool does not cut into the metal film, the metal film is cut by irradiating it with a laser beam. That is, no cutting tool is used in cutting the metal film, and therefore no burrs are generated from the metal film due to contact with a rotating cutting tool.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-78162

[0007] However, the aforementioned method of cutting metal films using laser beams requires the use of both cutting and laser processing equipment, which can easily lead to complex equipment and processes. As the equipment and processes become more complex, the cost of processing the workpiece also increases. Summary of the Invention

[0008] The present invention was made in view of this problem and its object is to provide a processing method for a workpiece that can process a workpiece containing a substrate such as a wafer and a ductile material layer such as a metal film using a simple process, and can suppress the generation of burrs from the ductile material layer.

[0009] According to one aspect of the present invention, a method for processing a workpiece is provided for processing a workpiece having a substrate and a ductile material layer, the substrate having a front side and a back side, the ductile material layer comprising a ductile material and disposed on the front side or the back side of the substrate, wherein the method for processing the workpiece comprises the following steps: a tape-adhering step, wherein a tape is adhered to the substrate side of the workpiece; a holding step, wherein the workpiece is held with respect to the tape in a manner that exposes the ductile material layer; and a cutting step, wherein after the holding step is performed, the holding stage is moved relative to a cutting tool, and the cutting tool cuts into the ductile material layer and the substrate, thereby cutting the workpiece, wherein in the cutting step, the cutting tool is rotated such that a portion of the cutting tool located in front of the cutting tool in the direction of movement relative to the holding stage cuts from the ductile material layer toward the substrate.

[0010] In one embodiment of the invention, the workpiece may sometimes include: a substrate having a plurality of devices disposed on the front side; and a ductile material layer disposed on the back side of the substrate, the ductile material layer being composed of a metal film.

[0011] In another embodiment of the present invention, the processing method for the workpiece preferably further includes the following position detection step: after the holding step is performed and before the cutting step is performed, the position at which the cutting tool cuts in is detected based on an image obtained by taking a picture of the front side of the substrate through the holding table and the belt.

[0012] Additionally, in one aspect of the invention, the workpiece sometimes comprises a substrate made of silicon carbide.

[0013] In one aspect of the workpiece processing method of the present invention, after the workpiece is held with a holding table in a manner that exposes the ductile material layer, the workpiece is cut by rotating the cutting tool in such a manner that a portion of the cutting tool located in front of the moving direction of the cutting tool relative to the holding table cuts into the substrate from the ductile material layer.

[0014] Therefore, even when a ductile material layer containing ductile material is in close contact with a cutting tool and is to be stretched, the ductile material layer is hardly stretched because the cutting tool removes the ductile material from the cutting tool by contacting the substrate made of a material harder than the ductile material. This suppresses the formation of burrs from the ductile material layer.

[0015] Furthermore, in one aspect of the processing method for the workpiece according to the present invention, it is not necessary to use both a cutting device and a laser processing device as in the case where a laser beam is used to cut the ductile material layer; therefore, the workpiece can be processed using a simple procedure. Thus, according to one aspect of the processing method for the workpiece according to the present invention, the workpiece can be processed using a simple procedure, and the generation of burrs from the ductile material layer can be suppressed. Attached Figure Description

[0016] Figure 1 It is a three-dimensional view showing the workpiece.

[0017] Figure 2 It is a three-dimensional view showing the state of the tape being attached to the workpiece.

[0018] Figure 3 This is a perspective view showing the cutting device.

[0019] Figure 4 This is a perspective view showing a portion of the cutting device.

[0020] Figure 5 It is a cross-sectional view showing a portion of the cutting device.

[0021] Figure 6 This is a perspective view showing a portion of the cutting device.

[0022] Figure 7 This is a cross-sectional view showing the workpiece being processed from below.

[0023] Figure 8 It is a cross-sectional view showing the cutting of the workpiece.

[0024] Label Explanation

[0025] 1: Workpiece; 11: Substrate; 11a: Front side; 11b: Back side; 13: Pre-defined dividing line (spacer); 15: Device; 17: Extensible material layer; 21: Belt; 21a: Substrate; 21b: Paste layer; 23: Frame; 2: Cutting device; 4: Base; 8: X-axis and Y-axis moving mechanism; 10: X-axis guide rail; 10a: X-axis scale; 12: X-axis moving table; 14: X-axis ball screw; 16: X-axis pulse motor; 20: Y-axis guide rail; 20a: Y-axis scale; 22: Y-axis moving table; 22a: Base plate; 22b: Side plate; 22c: Top plate; 22d: Space; 22e: Nut; 24: Y-axis ball screw; 26: Y-axis pulse motor; 28: Holding table; 30: Frame ; 30a: Pulley section; 30b: Fixture; 32: Holding component; 32a: Upper surface; 32b: Lower surface; 32c: Groove; 34: Rotary drive source; 34a: Pulley; 36: Belt; 38: Support structure; 40: Z-axis moving mechanism; 42: Z-axis guide rail; 44: Cutting unit; 46: Spindle housing; 48: Z-axis ball screw; 50: Z-axis pulse motor; 52: Cutting tool; 52a: Part; 54: Upper imaging unit; 56: Imaging unit support structure; 58: Imaging unit moving mechanism; 60: Z-axis guide rail; 62: Z-axis moving plate; 64: Z-axis ball screw; 66: Z-axis pulse motor; 68: Support arm; 70: Lower imaging unit; 72: Lighting device; 74: Camera; 76: Control unit. Detailed Implementation

[0026] The embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a perspective view showing a workpiece 1 being processed using the processing method of this embodiment. Figure 1 As shown, the workpiece 1 of this embodiment includes a substrate (wafer) 11 formed in a disk shape using a semiconductor material such as silicon carbide (SiC).

[0027] The substrate 11 is divided into multiple small regions by intersecting predetermined dividing lines (spacers) 13, and devices (power devices) such as inverters and converters for power control are formed in each small region. In addition, the pattern of the device 15 is configured in a way that can be identified from the front side 11a of the substrate 11.

[0028] A malleable material layer 17 containing a metal or other malleable material is provided on the back side 11b of the substrate 11, opposite to the front side 11a. The malleable material layer 17 is a metal film with a thickness of about 0.1 μm to 30 μm, formed using metals such as gold (Au), silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), and nickel (Ni), and functions as a heat sink, chip bonding agent (adhesive), etc.

[0029] Viewed from the front side 11a or the back side 11b of the substrate 11, the ductile material layer 17 is also formed in the area overlapping with the predetermined dividing line 13. Alternatively, the ductile material layer 17 may be a single metal film formed of an alloy containing the aforementioned metal. Furthermore, the ductile material layer 17 may also have a laminated structure consisting of multiple overlapping metal films, each formed of a single metal or alloy.

[0030] Furthermore, the workpiece 1 in this embodiment includes a disk-shaped substrate 11 formed using silicon carbide or the like, but there are no major limitations on the material, shape, structure, or size of the substrate 11. For example, the workpiece 1 may also include a substrate 11 formed from other semiconductor materials such as silicon (Si), gallium arsenide (GaAs), and gallium phosphide (GaP), ceramics, or resins. However, as described later, the substrate 11 needs to be formed from a material harder than the ductile material contained in the ductile material layer 17. Similarly, there are no limitations on the type, number, shape, structure, size, or arrangement of the devices 15. It is also possible not to form the devices 15 on the substrate 11.

[0031] In the processing method of the workpiece in this embodiment, a strip larger than the workpiece 1 is first pasted onto the substrate 11 side (the front side 11a side of the substrate 11, the side opposite to the ductile material layer 17) of the workpiece 1 (strip pasting step). Figure 2 This is a perspective view showing the state of the workpiece 1 with the band 21 pasted on it.

[0032] The band 21 typically includes a film-like substrate 21a (see reference). Figure 7 The tape 21 and the paste layer 21b disposed on one side of the substrate 21a are both transparent to visible light. The substrate 21a of the tape 21 is formed, for example, of a material such as polyolefin, vinyl chloride, or polyethylene terephthalate, and the paste layer 21b of the tape 21 is formed, for example, of an acrylic or rubber-based material. If the paste layer 21b side of the tape 21 is tightly attached to the front side 11a side of the substrate 11, the tape 21 is adhered to the workpiece 1.

[0033] A ring-shaped frame 23, made of a metal such as stainless steel (SUS) or aluminum, is fixed to the outer periphery of the paste layer 21b side of the belt 21. Therefore, the workpiece 1 is supported by the ring-shaped frame 23 via the belt 21. However, the workpiece 1 can also be processed without using the belt 21 and the frame 23.

[0034] Alternatively, a strip 21 without the paste layer 21b can be used. In this case, the strip 21 is bonded to the substrate 11 and the frame 23 by means of hot pressing while heating and applying pressure. By using a strip 21 without the paste layer 21b, the alignment of the cutting tool 52 and the predetermined dividing line 13 of the workpiece 1 becomes easier. Furthermore, from the viewpoint of facilitating this alignment, it is preferable to use a strip 21 that includes a flat substrate 21a (e.g., a substrate 21a that has not been embossed).

[0035] After the tape 21 is attached to the workpiece 1, the substrate 11 side of the workpiece 1 is held through the tape 21 in a manner that exposes the ductile material layer 17 (holding step). Figure 3 This is a perspective view showing the cutting device 2 used in the processing method of the workpiece in this embodiment. Additionally, in Figure 3 In this text, some components of the cutting device 2 are shown as function blocks, while some components of the cutting device 2 are omitted or simplified. Furthermore, the X-axis (machining feed direction), Y-axis (indexing feed direction), and Z-axis (height direction) used in the following description are perpendicular to each other.

[0036] like Figure 3 As shown, the cutting device 2 has a base 4. An X-axis and Y-axis moving mechanism (machining feed mechanism, indexing feed mechanism) 8 is arranged on the upper surface of the base 4. The X-axis and Y-axis moving mechanism 8 has a pair of X-axis guide rails 10 fixed to the upper surface of the base 4 and approximately parallel to the X-axis direction. The X-axis moving worktable 12 is slidably mounted on the X-axis guide rails 10.

[0037] A nut portion (not shown) is provided on the lower surface of the X-axis moving stage 12, and an X-axis ball screw 14, which is approximately parallel to the X-axis guide rail 10, is screwed into this nut portion. An X-axis pulse motor 16 is connected to one end of the X-axis ball screw 14. If the X-axis ball screw 14 is rotated by the X-axis pulse motor 16, the X-axis moving stage 12 moves along the X-axis guide rail 10 in the X-axis direction. An X-axis scale 10a, used for detecting the position of the X-axis moving stage 12 in the X-axis direction, is arranged next to the X-axis guide rail 10.

[0038] A pair of Y-axis guide rails 20, approximately parallel to the Y-axis direction, are provided on the upper surface of the X-axis moving stage 12. The Y-axis moving stage 22 is slidably mounted on the Y-axis guide rails 20. Figure 4 This is a perspective view showing a portion of the cutting device 2, including the Y-axis moving worktable 22. Figure 5 This is a cross-sectional view showing a portion of the cutting device 2, including the Y-axis moving worktable 22. Additionally, in Figure 5For ease of explanation, the shading lines of the cross-section have been omitted.

[0039] like Figure 4 and Figure 5 As shown, the Y-axis movable stage 22 includes a base plate portion 22a that is rectangular in shape when viewed from the Z-axis direction. A side plate portion 22b, also rectangular in shape when viewed from the Y-axis direction, is connected to one end of the base plate portion 22a at its lower end. A top plate portion 22c, which is rectangular in shape like the base plate portion 22a when viewed from the Z-axis direction, is connected to one end of the side plate portion 22b at its upper end. That is, a space 22d is formed between the base plate portion 22a and the top plate portion 22c, and this space 22d is connected to the outside at its other end in the Y-axis direction and both ends in the X-axis direction.

[0040] A nut portion 22e is provided on the lower surface of the base plate portion 22a of the Y-axis moving worktable 22. Figure 5 A Y-axis ball screw 24, which is approximately parallel to the Y-axis guide rail 20, is screwed into the nut portion 22e. A Y-axis pulse motor 26 is connected to one end of the Y-axis ball screw 24.

[0041] If the Y-axis ball screw 24 is rotated by the Y-axis pulse motor 26, the Y-axis moving table 22 moves along the Y-axis guide rail 20 in the Y-axis direction. A Y-axis scale 20a is provided next to the Y-axis guide rail 20 for detecting the position of the Y-axis moving table 22 in the Y-axis direction. Figure 1 ).

[0042] A holding table (chuck table) 28 for holding a plate-shaped workpiece 1 is disposed on the upper surface of the top plate portion 22c of the Y-axis moving table 22. The holding table 28 is supported on the top plate portion 22c in such a way that it can rotate about a rotation axis that is substantially parallel to the Z-axis direction.

[0043] The worktable 28 includes, for example, a cylindrical frame 30 formed using a metal such as stainless steel. A disc-shaped retaining member 32 is provided on the upper part of the frame 30 to seal the opening on the upper side of the frame 30. The retaining member 32 has a generally flat upper surface 32a and a lower surface 32b opposite to the upper surface 32a (see reference). Figure 7 (etc.), made of transparent materials that transmit visible light, such as soda-lime glass, borosilicate glass, and quartz glass.

[0044] like Figure 4 As shown, a plurality of grooves 32c for attracting the workpiece 1 are provided on the upper surface 32a of the holding member 32. A suction source (not shown) including an injector or the like is connected to these grooves 32c, and the negative pressure generated by the suction source is applied to the grooves 32c.

[0045] The holding member 32 is configured such that visible light can pass through at least a portion of its area, excluding the groove 32c, allowing for the imaging of the workpiece 1 disposed on the upper surface 32a side of the holding member 32 from the lower surface 32b side. Furthermore, while this embodiment shows a holding member 32 entirely made of transparent material, it is permissible for at least a portion of the holding member 32 to be transparent. That is, the holding member 32 may be made of more than just transparent material.

[0046] A rotary drive source 34, such as an electric motor, is provided on the side plate portion 22b of the Y-axis moving worktable 22. A belt 36 for transmitting power from the rotary drive source 34 is attached to the pulley portion 30a provided on the outer periphery of the frame 30 and to the pulley 34a connected to the rotation axis of the rotary drive source 34. Therefore, the worktable 28 is kept rotating about a rotation axis that is approximately parallel to the Z-axis direction by the force transmitted from the rotary drive source 34 via the belt 36.

[0047] In addition, besides the pulley portion 30a, a plurality of clamps 30b are provided on the outer periphery of the frame 30 for fixing the annular frame 23. The plurality of clamps 30b are fixed to the frame 30 in a manner that does not obstruct the rotation of the holding table 28. Furthermore, the holding table 28 moves together with the X-axis moving table 12 and the Y-axis moving table 22 in the X-axis and Y-axis directions via the aforementioned X-axis and Y-axis moving mechanisms 8.

[0048] like Figure 3 As shown, a columnar or wall-shaped support structure 38 is provided on the upper surface of the base 4 in an area that does not overlap with the X-axis and Y-axis moving mechanisms 8. A Z-axis moving mechanism 40 is arranged on the side of the support structure 38. The Z-axis moving mechanism 40 has a pair of Z-axis guide rails 42 fixed to the side of the support structure 38 and approximately parallel to the Z-axis direction.

[0049] The spindle housing 46, which constitutes the cutting unit (machining unit) 44, is slidably mounted on the Z-axis guide rail 42. A nut portion (not shown) is provided on the side of the spindle housing 46 on the support structure 38 side, in which a Z-axis ball screw 48, which is substantially parallel to the Z-axis guide rail 42, is screwed.

[0050] A Z-axis pulse motor 50 is connected to one end of the Z-axis ball screw 48. If the Z-axis ball screw 48 is rotated by the Z-axis pulse motor 50, the spindle housing 46 moves in the Z-axis direction along the Z-axis guide rail 42. A Z-axis scale (not shown) is provided next to the Z-axis guide rail 42 for detecting the position of the spindle housing 46 in the Z-axis direction.

[0051] The cutting unit 44 has a spindle (not shown) that serves as a rotation axis parallel to the Y-axis. The spindle is supported by the aforementioned spindle housing 46 in a rotatable state. The front end of the spindle protrudes from the spindle housing 46. A cutting tool 52 is mounted on the front end of the spindle, which is formed by fixing abrasive grains such as diamond using a bonding material such as metal. On the other hand, a rotation drive source (not shown) such as an electric motor is connected to the base end of the spindle.

[0052] An upper imaging unit 54 is fixed on the spindle housing 46 of the cutting unit 44. This upper imaging unit 54 is used to capture images of the workpiece 1 held by the holding table 28 from above. Thus, the upper imaging unit 54 moves together with the cutting unit 44 in the Z-axis direction via the Z-axis moving mechanism 40.

[0053] A columnar or wall-shaped imaging unit support structure 56 is provided on the upper surface of the base 4 in the area of ​​the Y-axis moving mechanism 8 away from the X-axis in the Y-axis direction. Figure 6 This is a perspective view showing a portion of the cutting device 2, including the imaging unit support structure 56. An imaging unit moving mechanism 58 is disposed on the side of the imaging unit support structure 56.

[0054] The shooting unit moving mechanism 58 has a pair of Z-axis guide rails 60 fixed to the side of the shooting unit support structure 56 and substantially parallel to the Z-axis direction. The Z-axis moving plate 62 is slidably mounted on the Z-axis guide rails 60. A nut portion (not shown) is provided on the side of the Z-axis moving plate 62 on the shooting unit support structure 56 side, and a Z-axis ball screw 64 substantially parallel to the Z-axis guide rails 60 is screwed into the nut portion.

[0055] A Z-axis pulse motor 66 is connected to one end of the Z-axis ball screw 64. If the Z-axis ball screw 64 is rotated by the Z-axis pulse motor 66, the Z-axis moving plate 62 moves along the Z-axis guide rail 60 in the Z-axis direction. A Z-axis scale (not shown) is provided next to the Z-axis guide rail 60 for detecting the position of the Z-axis moving plate 62 in the Z-axis direction.

[0056] A lower imaging unit 70 is fixed on the Z-axis moving plate 62 by means of a support arm 68 that is longer in the Y-axis direction. The lower imaging unit 70 includes: an illumination device 72 that illuminates the subject above (workpiece 1 in this embodiment) with visible light; and a camera 74 that has an imaging element that receives light reflected from the subject to form an image.

[0057] A control unit 76 is connected to the X-axis and Y-axis moving mechanisms 8, the rotary drive source 34, the Z-axis moving mechanism 40, the cutting unit 44, the upper imaging unit 54, the imaging unit moving mechanism 58, and the lower imaging unit 70. The control unit 76 is, for example, a computer including a processing unit such as a CPU and a storage device such as flash memory, and controls the operation of each component in a manner appropriate for processing the workpiece 1. The function of the control unit 76 is achieved by causing the processing unit to operate according to software stored in the storage device.

[0058] When holding the workpiece 1 on the substrate 11 side, such as Figure 5 As shown, firstly, the strip 21, which is attached to the substrate 11 side of the workpiece 1, comes into contact with the upper surface 32a of the holding member 32 of the holding table 28. Then, the negative pressure generated by the suction source is applied to the groove 32c. Finally, the frame 23 is fixed using the clamp 30b. Thus, the workpiece 1 is held on the holding table 28 with the ductile material layer 17 side exposed upwards.

[0059] After holding the workpiece 1 on the substrate 11 side using the holding table 28, the position of the dividing predetermined line 13 (the position where the cutting tool 52 cuts into the workpiece 1) is detected based on the image obtained by taking a picture of the workpiece 1 from below (position detection step). Figure 7 This is a cross-sectional view showing the workpiece 1 being photographed from below.

[0060] Specifically, the control unit 76 controls the movements of the X-axis and Y-axis moving mechanisms 8 and the shooting unit moving mechanism 58, such as... Figure 7 As shown, the lower imaging unit 70 is positioned below the area of ​​the holding member 32 that is transparent to visible light. That is, the lower imaging unit 70 is inserted into the space 22d between the bottom plate portion 22a and the top plate portion 22c of the Y-axis moving stage 22. The positional relationship between the holding member 32 and the lower imaging unit 70 can be arbitrarily adjusted within a range suitable for imaging the workpiece 1.

[0061] As described above, a portion of the holding member 32 and the belt 21 are transparent to visible light. Therefore, if visible light is shone from the illumination device 72 of the lower imaging unit 70 onto the workpiece 1 above, and the imaging element of the camera 74 receives the light reflected from the lower surface of the workpiece 1 (the front surface 11a of the substrate 11), an image of the front surface 11a of the substrate 11 can be captured. Thus, in this embodiment, the front surface 11a of the substrate 11 is captured through the holding member 32 (holding stage 28) and the belt 21.

[0062] The image obtained by camera 74 is sent to control unit 76, for example. Control unit 76 applies pattern matching, such as the feature pattern of extraction device 15, to the image sent from camera 74, thereby detecting the position of the pre-cutting line 13 into which the cutting tool 52 cuts. The detected position of the pre-cutting line 13 is stored in the storage device of control unit 76.

[0063] After detecting the position of the predetermined dividing line 13, the rotating cutting tool 52 cuts into the workpiece 1 to cut it (cutting step). Figure 8 This is a cross-sectional view showing the cutting of the workpiece 1. Specifically, for example, the operation of the rotary drive source 34 is controlled by the control unit 76 so that the predetermined dividing line 13, which is the object being processed, is approximately parallel to the X-axis direction. In addition, the operation of the X-axis and Y-axis moving mechanism 8 is controlled by the control unit 76 so that the position of the cutting tool 52 is aligned above the extension line of the predetermined dividing line 13, which is the object being processed.

[0064] Furthermore, the Z-axis movement mechanism 40 is controlled by the control unit 76, and the Z-axis position of the cutting unit 44 is adjusted such that the height of the lower end of the cutting tool 52 is lower than the height of the lower surface of the workpiece 1 (the front surface 11a of the substrate 11). Then, as... Figure 8 As shown, while the cutting tool 52 is rotated, the holding table 28 is moved in the X-axis direction (first direction X1) using the X-axis and Y-axis moving mechanism 8. That is, the holding table 28 and the cutting tool 52 move relative to each other in the X-axis direction.

[0065] Here, the direction R1 for rotating the cutting tool 52 is set as follows: the direction in which the cutting tool 52 moves relative to the holding table 28 is the second direction X2 (opposite to the first direction X1), and a portion 52a of the cutting tool 52 located in front of this second direction X2 cuts into the substrate 11 from the ductile material layer 17. That is, the cutting tool 52 is rotated in such a way that a portion 52a of the cutting tool 52 moves from top to bottom.

[0066] When the cutting tool 52 is rotated in such a direction R1, even if the ductile material layer 17 containing ductile material is in close contact with the cutting tool 52 and is to be stretched, the ductile material layer 17 is hardly stretched because the cutting tool 52 contacts the substrate 11, which is made of a material harder than the ductile material, thereby removing the ductile material in close contact with the cutting tool 52. Thus, the generation of burrs from the ductile material layer 17 can be suppressed.

[0067] Through the above steps, the cutting tool 52 cuts into the workpiece 1 (ductile material layer 17 and substrate 11) along the predetermined dividing line 13 that is the object being processed. As a result, the workpiece 1 is cut along the predetermined dividing line 13. This step is repeated until the workpiece 1 is cut along all the predetermined dividing lines 13 provided on the workpiece 1.

[0068] Furthermore, it was confirmed that burr formation from the ductile material layer 17 can be suppressed to a particularly high level under the following conditions. Using a thinner cutting tool 52 that meets the conditions reduces the volume of the ductile material layer 17 removed by cutting, which also greatly helps to suppress burr formation.

[0069] Substrate material: Silicon carbide (SiC)

[0070] Substrate thickness: 50μm or more and 360μm or less

[0071] Materials used for the ductile layer: Gold (Au), Silver (Ag), Copper (Cu), Aluminum (Al), Titanium (Ti), Nickel (Ni)

[0072] Thickness of the ductile material layer: ≥0.1μm and ≤30μm

[0073] The interval between the pre-defined dividing lines: 0.5mm or more and 5mm or less

[0074] Types of cutting tools: Electroforming tools

[0075] Cutting tool thickness: 15μm or more and 40μm or less

[0076] The abrasive grain size (grit grade) of the cutting tool: #1200 and above, and #2000 and below.

[0077] The rotational speed of the cutting tool (circumferential speed of the cutting tool): 15,000 rpm or higher and 30,000 rpm or lower (2,600 m / min or higher and 5,300 m / min or lower).

[0078] Maintain the following table feed speed: ≥20 mm / s and ≤100 mm / s when a ductile material layer is formed on the C-surface of silicon carbide; ≥1 mm / s and ≤10 mm / s when a ductile material layer is formed on the Si-surface of silicon carbide.

[0079] As described above, in the workpiece processing method of this embodiment, after the workpiece 1 is held in place by the holding table 28 with the belt 21 in a manner that exposes the ductile material layer 17, the workpiece 1 is cut by rotating the cutting tool 52 in such a manner that a portion 52a of the cutting tool 52 located in front of the moving direction (second direction X2) of the cutting tool 52 relative to the holding table 28 cuts into the substrate 11 from the ductile material layer 17.

[0080] Therefore, even when the ductile material layer 17, containing ductile material, is in close contact with the cutting tool 52 and is to be stretched, the ductile material layer 17 is hardly stretched because the cutting tool 52 contacts the substrate 11, which is made of a material harder than the ductile material, thereby removing the ductile material in close contact with the cutting tool 52. This suppresses the generation of burrs from the ductile material layer 17.

[0081] Furthermore, in the workpiece processing method of this embodiment, it is not necessary to use both a cutting device and a laser processing device as in the case where the ductile material layer 17 is cut using a laser beam. Therefore, the workpiece 1 can be processed using a simple process. Thus, according to the workpiece processing method of this embodiment, the workpiece 1 can be processed using a simple process, and the generation of burrs from the ductile material layer 17 can be suppressed.

[0082] Furthermore, the present invention is not limited to the embodiments described above, and various modifications and implementations are possible. For example, it has been confirmed that when processing a workpiece containing a substrate formed using silicon (Si), burr formation from the ductile material layer can be suppressed to a high level by satisfying the following conditions. Using a thinner cutting tool that meets the conditions reduces the volume of the ductile material layer removed by cutting, which also greatly helps to suppress burr formation.

[0083] Substrate material: Silicon (Si)

[0084] Substrate thickness: 10μm or more and 300μm or less

[0085] Materials used for the ductile layer: Gold (Au), Silver (Ag), Copper (Cu), Aluminum (Al), Titanium (Ti), Nickel (Ni)

[0086] Thickness of the ductile material layer: ≥0.1μm and ≤30μm

[0087] The interval between the pre-defined dividing lines: 0.1mm or more and 5mm or less

[0088] Types of cutting tools: Electroforming tools

[0089] Cutting tool thickness: 5μm or more and 40μm or less

[0090] The abrasive grain size (grit grade) contained in the cutting tool: #1500 and above and #3500 and below

[0091] The rotational speed of the cutting tool (circumferential speed of the cutting tool): above 15,000 rpm and below 60,000 rpm (above 2,600 m / min and below 10,500 m / min).

[0092] Maintain a table feed rate of 30 mm / s or higher but less than 200 mm / s.

[0093] Furthermore, while the above embodiment describes an example of cutting the workpiece 1 using the cutting tool 52, the workpiece processing method of the present invention can also be applied when the workpiece is partially cut using the cutting tool. In this case, the Z-axis position of the cutting unit can be adjusted such that the height of the lower end of the cutting tool is higher than the height of the lower surface of the workpiece (the front side of the substrate) and lower than the height of the interface between the substrate and the ductile material layer (the back side of the substrate).

[0094] Furthermore, in the above embodiment, an example of processing a workpiece 1 containing a metal film as a ductile material layer 17 was described. However, the ductile material layer contained in the workpiece does not need to be a metal film, as long as it contains a ductile material that is more ductile than the material of the substrate. For example, sometimes the ductile material layer is a resin film formed using resin. In addition, the ductile material layer can be provided on the front side of the substrate.

[0095] In addition, the above-described embodiments or variations of the construction and methods can be appropriately modified and implemented as long as they do not depart from the scope of the present invention.

Claims

1. A method for processing a workpiece, used when processing a workpiece having a substrate and a ductile material layer, the substrate having a front side and a back side, the ductile material layer comprising a ductile material and disposed on the front side or the back side of the substrate, wherein, The processing method for the workpiece includes the following steps: The tape is attached to the substrate side of the workpiece using a bonding step. The workpiece is held in a manner that exposes the ductile material layer by using a holding table. In the cutting step, after the holding step, the holding table is moved relative to the cutting tool, causing the cutting tool to cut into the ductile material layer and the substrate, thereby cutting the workpiece; and, The position detection step, performed after the holding step and before the cutting step, involves detecting the position where the cutting tool will enter the substrate based on an image obtained by photographing the substrate using visible light over the holding table and the belt. In this cutting step, the cutting tool is rotated such that a portion of the cutting tool located in front of the moving direction of the cutting tool relative to the holding table cuts into the ductile material layer toward the substrate.

2. The processing method for the workpiece according to claim 1, wherein, In this tape bonding step, the tape without a paste layer is bonded to the substrate side of the workpiece by applying pressure while heating.

3. The processing method for the workpiece according to claim 2, wherein, The workpiece contains: The substrate has multiple devices disposed on its front side; and The ductile material layer is disposed on the back side of the substrate. The ductile material layer is composed of a metal film.

4. The processing method for the workpiece according to any one of claims 1 to 3, wherein, The workpiece includes the substrate made of silicon carbide.

Images