Processing method of workpiece

Abstract

Provided is a processing method of a processed object, which facilitates expansion of an area adhered to the processed object when expanding an expansion sheet supporting the processed object. The processing method of the processed object includes a heat-hardening step of hardening the expansion sheet around the processed object by heating the expansion sheet to a prescribed temperature or higher and then cooling the expansion sheet, and an expansion step of expanding the expansion sheet around the processed object in a planar direction after the heat-hardening step is performed, to divide the processed object into chips or to expand the interval of the chips.

Description

Technical Field

[0001] The present invention relates to a method for processing a workpiece. Background Art

[0002] A disc-shaped workpiece, such as a semiconductor wafer, with a plurality of devices formed on the front surface is divided along predetermined dividing lines between the devices and singulated into semiconductor chips. A technique is known in which the workpiece is fixed on an expansion piece that closes the opening of an annular frame and is divided into chips by expanding an expansion piece. In addition, the following technique is also known: after the workpiece, which has been previously divided into chips by cutting or DBG (Dicing Before Grinding), is fixed to an annular frame using an expansion piece, the distance between the chips is increased by expanding the expansion piece. As an expansion method used in these processes, the following method is known: while the annular frame is maintained, the workpiece is lifted in a direction away from the annular frame to expand the expansion piece (for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-049591

[0004] Patent Document 2: Japanese Patent Application Laid-Open No. 2014-063812

[0005] Patent Document 3: Japanese Patent No. 4971869

[0006] In the aforementioned expansion method, the area of ​​the expansion sheet alone on the periphery of the workpiece tends to stretch more than the area to which the workpiece is attached, resulting in a problem in which the expansion effect cannot be fully utilized to divide or separate the workpiece. Therefore, an expansion method has been proposed in which the belt is expanded in four directions before being secured to the annular frame. However, this method requires the expansion sheet to be secured to the annular frame after expansion, making it difficult to use when the expansion sheet has been previously secured to the annular frame. Summary of the Invention

[0007] Therefore, an object of the present invention is to provide a method for processing a workpiece, which can promote the expansion of a region attached to the workpiece when expanding an expansion sheet supporting the workpiece.

[0008] According to the present invention, a method for processing a workpiece is provided, in which an extension piece of a frame unit is expanded to divide the workpiece into individual chips or to increase the distance between the chips. The frame unit is formed by supporting a plate-shaped workpiece having a starting point for division along a predetermined division line or a plate-shaped workpiece divided into multiple chips at an opening of an annular frame using the extension piece having heat-curing properties, wherein the method for processing the workpiece has the following steps: a heat-curing step, in which the extension piece around the workpiece is heated to a temperature above a specified temperature and then cooled to harden the extension piece around the workpiece compared to before heating; and an expansion step, in which, after the heat-curing step is implemented, the extension piece on the periphery of the workpiece is expanded in a surface direction to divide the workpiece into chips or to increase the distance between the chips.

[0009] Preferably, the expansion sheet includes a base material layer and an adhesive layer, and the base material layer or the adhesive layer is formed of a thermosetting resin.

[0010] Preferably, the heat-hardening step is performed in a region of the expansion sheet that overlaps a direction in which it is desired to expand more than other directions.

[0011] Preferably, the workpiece processing method further comprises a slack removing step of heating the expansion piece that has been relaxed around the periphery of the workpiece again to shrink the expansion piece after the expansion step.

[0012] The present invention can promote the expansion of the region attached to the workpiece when the expansion sheet supporting the workpiece is expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a perspective view showing an example of a frame unit to be processed in the method for processing a workpiece according to the embodiment.

[0014] Figure 2 yes Figure 1 A cross-sectional view of the main parts of the frame unit is shown.

[0015] Figure 3 It is a perspective view showing a configuration example of an expansion device used in the method for processing a workpiece according to the embodiment.

[0016] Figure 4 It will Figure 3 The expansion device shown is an exploded perspective view.

[0017] Figure 5 This is a flowchart showing the flow of a method for processing a workpiece according to an embodiment.

[0018] Figure 6 It shows Figure 5A cross-sectional view of a main portion of an expansion device showing one state in a thermal hardening step of a method for processing a workpiece is shown.

[0019] Figure 7 It shows Figure 5 In the heat curing step of the workpiece processing method shown Figure 6 A sectional view of the main parts of the expansion device in a subsequent state.

[0020] Figure 8 It shows Figure 5 A cross-sectional view of the main parts of the expansion device after the expansion step of the workpiece processing method shown.

[0021] Figure 9 It is a perspective view showing a configuration example of a heating and cooling unit of an expansion device used in a method for processing a workpiece according to a first modified example.

[0022] Figure 10 It is a plan view showing an example of a workpiece to be processed by the workpiece processing method according to the second modified example.

[0023] Figure 11 This is a cross-sectional view of a main portion of a workpiece in which the chip interval is enlarged by the workpiece processing method according to the third modified example.

[0024] Figure 12 This is a flowchart showing the flow of a method for processing a workpiece according to a fourth modification.

[0025] Figure 13 It shows Figure 12 A cross-sectional view of a main portion of an expanding device in one state in a slack removing step of a method for machining a workpiece is shown.

[0026] Figure 14 It shows Figure 12 A cross-sectional view of the main parts of the expansion device after the slack removal step of the workpiece processing method is shown.

[0027] Description of labels

[0028] 10, 10-2: expansion device; 20: chamber; 30: chuck worktable; 31: holding surface; 40: frame holding part; 50: chip spacing forming unit; 60: heating unit; 60-2: heating and cooling unit; 200: frame unit; 201, 201-2, 201-3: workpiece; 202: chip; 203: substrate; 204: predetermined dividing line; 205: device; 206: front side; 207: back side; 208: modified layer (division starting point); 209: functional layer; 210: annular frame; 211: expansion piece; 212: annular area. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the contents described in the following embodiments. In addition, the structural elements described below include substantially the same structural elements that can be easily imagined by those skilled in the art. Moreover, the structures described below can be appropriately combined. In addition, various omissions, substitutions, or modifications of the structures can be made without departing from the scope of the present invention.

[0030] [Implementation Method]

[0031] A method for processing a workpiece 201 according to an embodiment of the present invention will be described with reference to the drawings. First, the structure of the frame unit 200 to be processed and the structure of the expansion device 10 used for the method for processing the workpiece 201 will be described. Figure 1 This is a perspective view showing an example of a frame unit 200 to be processed in the method of processing a workpiece 201 according to the embodiment. Figure 2 yes Figure 1 1 is a cross-sectional view of a main portion of the frame unit 200 shown. Figure 3 1 is a perspective view showing a configuration example of the expansion device 10 used in the method for processing the workpiece 201 according to the embodiment. Figure 4 It will Figure 3 The expansion device 10 shown is an exploded perspective view showing an example of its structure.

[0032] The workpiece 201 to be processed in the embodiment is processed by Figure 3 and Figure 4 The expansion device 10 shown is divided into Figure 1 The following description describes a case where the workpiece 201 of the embodiment is divided into a plurality of chips 202 along a modified layer 208 formed on the workpiece 201 by the expansion device 10. The workpiece 201 is a wafer such as a circular semiconductor wafer or an optical device wafer having a substrate 203 made of silicon (Si), sapphire (Al2O3), gallium arsenide (GaAs), or silicon carbide (SiC). The workpiece 201 has a plurality of predetermined dividing lines 204 formed on the front surface 206 of the substrate 203 and devices 205 formed in each region divided by the plurality of predetermined dividing lines 204 intersecting in a grid pattern.

[0033] In addition, if Figure 2As shown, the workpiece 201 has a functional layer 209 stacked on the front surface of the substrate 203. In an embodiment, the functional layer 209 includes a low-dielectric-constant insulator coating (hereinafter referred to as a Low-k film) and a conductive film. The low-dielectric-constant insulator coating is composed of an inorganic film such as SiOF, BSG (SiOB) or an organic film such as a polyimide-based or parylene-based polymer film, and the conductive film is composed of a conductive metal. The Low-k film and the conductive film are stacked to form the device 205. The conductive film constitutes the circuit of the device 205. Therefore, the device 205 is composed of Low-k films stacked on each other and a conductive film stacked between the Low-k films. In addition, the functional layer 209 of the predetermined dividing line 204 is composed of a Low-k film and does not have a conductive film except for the TEG (Test Element Group). The TEG is an evaluation element used to identify design and manufacturing problems that may occur in the device 205.

[0034] The workpiece 201 is supported by an annular frame 210 and an expansion piece 211. The annular frame 210 has an opening larger than the outer diameter of the workpiece 201. The outer periphery of the expansion piece 211 is adhered to the back side of the annular frame 210. The workpiece 201 is positioned at a predetermined position in the opening of the annular frame 210 and the back side 207 is adhered to the expansion piece 211, thereby being fixed by the annular frame 210 and the expansion piece 211.

[0035] The expansion sheet 211 is made of a stretchable resin that has thermosetting properties, hardening by heating and cooling, and shrinking by heating. For example, the expansion sheet 211 may include: a base layer made of a stretchable synthetic resin; and an adhesive layer laminated on the base layer and made of a stretchable and adhesive synthetic resin. At least one of the base layer and the adhesive layer is formed of a thermosetting resin. The expansion sheet 211 may also contain an antioxidant.

[0036] In the embodiment, the expansion sheet 211 is attached and fixed to the back surface 207 of the workpiece 201. However, in the present invention, the expansion sheet 211 may be attached and fixed to the front surface 206 of the workpiece 201. Alternatively, a die-bonding film may be interposed between the expansion sheet 211 and the workpiece 201.

[0037] By irradiating substrate 203 with laser light of a wavelength that is transparent to the substrate 203 from the back surface 207 along the intended dividing line 204, the workpiece 201 forms a modified layer 208 within substrate 203, which serves as the starting point for division along the intended dividing line 204. Modified layer 208 refers to a region whose density, refractive index, mechanical strength, and other physical properties differ from those of the surrounding regions. Examples of modified layer 208 include a melt-processed region, a crack region, a dielectric breakdown region, a refractive index change region, and a region where these regions are mixed. In embodiments, the mechanical strength of modified layer 208 is lower than that of the rest of substrate 203.

[0038] The frame unit 200 is composed of a workpiece 201 having a modified layer 208 formed along a predetermined dividing line 204, an expansion sheet 211 attached to the back surface 207 of the workpiece 201, and an annular frame 210 attached to the outer periphery of the expansion sheet 211. Specifically, the frame unit 200 is composed of the workpiece 201, the expansion sheet 211, and the annular frame 210.

[0039] The workpiece 201 having a modified layer 208 formed thereon is divided into individual devices 205 along the planned dividing lines 204 by applying an external force, thereby producing a chip 202. The chip 202 includes a portion of a substrate 203 and the devices 205 on the substrate 203. The planar shape of the chip 202 is square in the embodiment, but it may also be rectangular in the present invention.

[0040] The external force for dividing the workpiece 201 into individual chips 202 is Figure 3 and Figure 4 The expansion device 10 shown in FIG. 1 is provided. The expansion device 10 includes a chamber 20, a chuck table 30, a frame holding portion 40, a chip spacing forming unit 50, a heating unit 60, and a control unit 80. In addition, Figure 3 and Figure 4 The X direction and the Y direction are both included in the horizontal direction and are perpendicular to each other.

[0041] The chamber 20 is shaped like a box with an open top. It houses the chuck table 30, the frame mounting plate 41 of the frame holder 40, and the chip spacing unit 50. The chamber 20 also has a loading / unloading port (not shown) for accessing the frame unit 200 and opening and closing the port via a door 21. The upper opening of the chamber 20 is sealed by a cover member 22 that covers the heating unit 60 from above.

[0042] The chamber 20 is preferably sealed with its upper opening sealed by a lid member 22 and its loading / unloading port sealed by an opening / closing door 21. The expansion device 10 may also include a nitrogen gas supply source for supplying nitrogen gas, an inert gas, into the chamber 20. By purging the chamber 20 with nitrogen, oxygen is prevented from contacting the expansion sheet 211 during heating and cooling in the thermal curing step ST1 described later, thereby suppressing degradation of the expansion sheet 211 due to oxidation.

[0043] The chuck table 30 uses a holding surface 31 to attract and secure the plurality of chips 202 via the expansion piece 211, while maintaining the expanded spacing between the chips 202. The chuck table 30 is in the shape of a circular plate. The chuck table 30 includes a holding surface 31 for attracting and holding the workpiece 201 of the frame unit 200 via the expansion piece 211. The holding surface 31 of the chuck table 30 is made of a porous material such as porous ceramics.

[0044] The frame unit 200 is transported to the chuck table 30 by a transport unit (not shown). The chuck table 30 places the back surface 207 of the workpiece 201 on the holding surface 31 via the expansion piece 211 of the frame unit 200. The holding surface 31 of the chuck table 30 is sucked by a vacuum suction source, so that the back surface 207 of the workpiece 201 can be sucked and held on the holding surface 31.

[0045] The frame holding portion 40 holds and fixes the annular frame 210 of the frame unit 200 . The frame holding portion 40 includes a frame placement plate 41 and a frame pressing plate 42 .

[0046] The frame loading plate 41 is provided with an opening portion 411 having a circular planar shape, and an upper surface 412 is formed in the shape of a plate that is parallel to the horizontal direction and flat. The frame loading plate 41 is provided so as to fix the position in the vertical direction by means of foot members 43 that respectively support the four corners. The inner diameter of the opening portion 411 of the frame loading plate 41 is formed to be equal to the inner diameter of the annular frame 210. The frame loading plate 41 is provided with a chuck table 30 in the opening portion 411. The opening portion 411 is coaxially arranged with the chuck table 30. The annular frame 210 of the frame unit 200 transported by a transport unit (not shown) is placed on the upper surface 412 of the frame loading plate 41.

[0047] The frame pressing plate 42 is formed into a plate-like shape having approximately the same dimensions as the frame mounting plate 41. A circular opening 421 having the same dimensions as the opening 411 is provided at the center of the frame pressing plate 42. The frame pressing plate 42 is fixed within the chamber 20. The frame holding portion 40 clamps and secures the annular frame 210 of the frame unit 200 between the frame mounting plate 41 and the frame pressing plate 42.

[0048] The chip spacing unit 50 moves the workpiece 201 relative to the frame holding portion 40 by a predetermined distance in a direction perpendicular to the front surface 206 of the workpiece 201, thereby expanding the expansion piece 211. By expanding the expansion piece 211, the chip spacing unit 50 divides the workpiece 201 into a plurality of chips 202 along the predetermined dividing lines 204 and increases the spacing between the chips 202 to a desired distance. The chip spacing unit 50 includes a table lifting unit 53 and a lifting member 51. The table lifting unit 53 moves the chuck table 30 in a direction perpendicular to the holding surface 31, i.e., in the vertical direction.

[0049] The lifting member 51 is formed into a cylindrical shape. The lifting member 51 is formed so that its outer diameter is smaller than the inner diameter of the annular frame 210 placed on the upper surface 412 of the frame mounting plate 41. The lifting member 51 is formed so that its inner diameter is larger than the outer diameters of the workpiece 201 and the chuck table 30 attached to the expansion piece 211. The lifting member 51 is arranged on the inner side of the chuck table 30 and is arranged on the outer periphery of the chuck table 30. The lifting member 51 is arranged coaxially with the chuck table 30. A roller member 511 ( Figure 6 The roller member 511 reduces friction between the lifting member 51 and the expansion piece 211 when the lifting member 51 lifts the expansion piece 211. In the embodiment, the lifting member 51 is lifted and lowered integrally with the chuck table 30 by the table lifting unit 53.

[0050] The expansion piece 211 is raised integrally from a state where the roller member 511 and the holding surface 31 are flush with the upper surface 412 of the raised frame mounting plate 41, thereby expanding in the surface direction. The table lifting unit 53 causes the lift member 51, on which the roller member 511 is attached at its upper end, and the chuck table 30 having the holding surface 31 to integrally rise, thereby expanding the expansion piece 211 in the surface direction.

[0051] The heating unit 60 heats the expansion sheet 211 around the workpiece 201 to a predetermined temperature or higher. The heating unit 60 includes a disk-shaped unit body 61 , a plurality of heat source units 62 attached to the unit body 61 , a rotating unit 63 , and a lifting unit 64 .

[0052] The unit body 61 is disposed above the chuck table 30 and coaxially therewith. The unit body 61 is rotatable about an axis parallel to the vertical direction by a rotating unit 63. The unit body 61 is elevatable by an elevating unit 64.

[0053] The heat source parts 62 are arranged at equal intervals along the circumferential direction on the outer edge of the unit body 61. The heat source parts 62 are arranged at a position vertically opposite the annular area 212, wherein the annular area 212 is the area between the inner edge of the annular frame 210 of the expansion piece 211 of the frame unit 200 held by the chuck table 30 and the frame holding part 40 and the outer edge of the workpiece 201. The heat source parts 62 locally heat the area between the inner edge of the annular frame 210 of the expansion piece 211 and the outer edge of the workpiece 201. In the embodiment, four heat source parts 62 are provided, but the present invention is not limited to four. The heat source parts 62 are components that irradiate infrared rays downward to heat the annular area 212 of the expansion piece 211, for example, an infrared ceramic heater that is heated and radiates infrared rays when a voltage is applied, but the present invention is not limited to this.

[0054] The rotating unit 63 moves the heat source 62 circumferentially around the periphery of the workpiece 201. In the embodiment, the rotating unit 63 moves the heat source 62 circumferentially around the periphery of the workpiece 201 by rotating the unit body 61. However, the rotating unit 63 may move the heat source 62 relative to the unit body 61 in the circumferential direction.

[0055] The lifting unit 64 adjusts the distance between the heat source 62 of the heating unit 60 and the expansion piece 211. In the embodiment, the lifting unit 64 adjusts the distance between the heat source 62 and the expansion piece 211 in the vertical direction by lifting the unit body 61, but the heat source 62 may also be moved relative to the unit body 61 in the vertical direction.

[0056] The control unit 80 controls the aforementioned components of the expansion device 10, namely, the chip spacing forming unit 50 and the heating unit 60, so that the expansion device 10 performs processing operations on the workpiece 201. The control unit 80 is, for example, a computer and includes: an arithmetic processing unit having a microprocessor such as a CPU (central processing unit); a storage device having a memory such as a ROM (read-only memory) or a RAM (random access memory); and an input / output interface device. The control unit 80 is connected to a display unit (not shown) and an input unit (not shown). The display unit includes a liquid crystal display device that displays the status and images of the processing operation, and the input unit is used by the operator to register processing details. The input unit includes at least one of an external input device such as a touch panel provided on the display unit and a keyboard.

[0057] The control unit 80 controls the heat source 62 of the heating unit 60 by, for example, applying a voltage to the heat source 62, thereby heating the heat source 62 to a predetermined temperature. The control unit 80 controls the rotation unit 63, for example, to move the heat source 62 of the heating unit 60 circumferentially around the periphery of the workpiece 201. The control unit 80 controls the lifting unit 64, for example, to adjust the distance between the heat source 62 of the heating unit 60 and the expansion sheet 211. While the heating unit 60 is heating the expansion sheet 211, the control unit 80 can also raise and lower the heat source 62 via the lifting unit 64 to adjust the amount of heat supplied to the expansion sheet 211.

[0058] The control unit 80 controls the chip spacing forming unit 50, for example, so that the chuck table 30 and the frame holding part 40 move between the extended position and the close position. The extended position indicates the position where the chuck table 30 and the frame holding part 40 are separated along the axis so that the expansion piece 211 is expanded. In more detail, the extended position indicates the position of the chuck table 30 and the frame holding part 40 when the holding surface 31 of the chuck table 30 and the upper surface 412 of the frame loading plate 41 of the frame holding part 40 are separated along the axis direction. The close position indicates the position where the chuck table 30 and the frame holding part 40 are close to each other. In more detail, the close position indicates the position of the chuck table 30 and the frame holding part 40 when the holding surface 31 of the chuck table 30 and the upper surface 412 of the frame loading plate 41 of the frame holding part 40 are positioned on the same plane.

[0059] Next, a method of expanding the expansion piece 211 using the expansion device 10 of the embodiment to divide the workpiece 201 into a plurality of chips 202 along the planned dividing lines 204 and increasing the intervals between the chips 202 to a desired distance will be described. Figure 5 1 is a flow chart showing the process of the method for processing the workpiece 201 according to the embodiment. Figure 5 As shown, the method for processing the workpiece 201 includes a thermal hardening step ST1 and an expansion step ST2.

[0060] Figure 6 It shows Figure 5 The figure shows a cross-sectional view of the main parts of the expansion device 10 in one state in the heat curing step ST1 of the method for processing the workpiece 201. The heat curing step ST1 is a step in which the expansion sheet 211 around the workpiece 201 is heated to a predetermined temperature or higher and then cooled to harden the workpiece 201 to a temperature higher than before heating.

[0061] In the embodiment, in the thermal curing step ST1, the control unit 80 causes the opening and closing door 21 to open the loading and unloading port of the chamber 20 (see Figure 3 ), the transport unit (not shown) Figure 2The frame unit 200, on which the modified layer 208 is formed along the planned dividing line 204, is loaded into the chamber 20 through the loading / unloading port and transported above the chuck table 30. The control unit 80 uses the transport unit to place the back surface 207 of the workpiece 201 on the holding surface 31 via the expansion piece 211, and then places the annular frame 210 on the upper surface 412 of the frame mounting plate 41.

[0062] Next, the control unit 80 is secured to the frame holding portion 40 by sandwiching the annular frame 210 between the frame mounting plate 41 and the frame pressing plate 42. The control unit 80 lowers the unit body 61 of the heating unit 60 via the lifting unit 64, bringing the heat source 62 of the heating unit 60 closer to the expansion piece 211. At this point, the upper surface 412 of the frame mounting plate 41, the holding surface 31 of the chuck table 30, and the roller member 511 attached to the upper end of the lift member 51 are coplanar, so that the roller member 511 contacts the annular region 212 of the expansion piece 211.

[0063] Next, in the heat curing step ST1, the expansion sheet 211 around the workpiece 201 is heated to a predetermined temperature or above. The predetermined temperature is, for example, 60 to 100°C. The control unit 80 heats the heat source portion 62 of the heating unit 60 to a predetermined temperature by applying a voltage to the heat source portion 62. The predetermined temperature is a predetermined constant temperature. The heated heat source portion 62 radiates infrared rays. Figure 6 As shown, the control unit 80 moves the heat source 62 of the heating unit 60 close to the annular region 212 of the expansion piece 211 to heat the expansion piece 211. The heating unit 60 is rotated about its axis by the rotation unit 63, so that the heat source 62 moves circumferentially in the annular region 212 of the expansion piece 211.

[0064] At this time, the control unit 80 may also control the lifting unit 64 of the heating unit 60 according to conditions preset by the operator. The control unit 80 raises and lowers the unit body 61 via the lifting unit 64, thereby adjusting the vertical distance between the heat source portion 62 and the expansion piece 211. The control unit 80 increases the amount of heat supplied to the expansion piece 211 by shortening the distance between the annular region 212 of the expansion piece 211 and the heat source portion 62 of the heating unit 60. The control unit 80 decreases the amount of heat supplied to the expansion piece 211 by lengthening the distance between the annular region 212 of the expansion piece 211 and the heat source portion 62 of the heating unit 60. The control unit 80 may also adjust the heating time of the heating unit 60 according to conditions preset by the operator.

[0065] Figure 7 It shows Figure 5 In the heat curing step ST1 of the processing method for the workpiece 201 shown in FIG. Figure 6A cross-sectional view of the main part of the expansion device 10 in a state after the heat treatment. Next, in the heat curing step ST1, the expansion piece 211 around the workpiece 201 is cooled to be harder than before the heating. The control unit 80 stops the heating of the heat source part 62 of the heating unit 60. Figure 7 As shown, the control unit 80 raises the unit body 61 of the heating unit 60 via the lifting unit 64, separating the heat source portion 62 of the heating unit 60 from the annular region 212 of the expansion sheet 211. In the thermal curing step ST1, in the embodiment, the workpiece 201 is cooled by being exposed to room temperature for a predetermined period of time. Since the expansion sheet 211 is thermosetting, the expansion sheet 211 is cured by cooling after heating. Specifically, the annular region 212 of the expansion sheet 211 is cured more than the region attached to the workpiece 201.

[0066] Figure 8 It shows Figure 5 The figure shows a cross-sectional view of the main part of the expanding device 10 after the expanding step ST2 of the method for processing the workpiece 201. The expanding step ST2 is a step of expanding the expanding piece 211 on the outer periphery of the workpiece 201 in the surface direction after the thermal curing step ST1 is performed.

[0067] In the expansion step ST2, first, the chuck table 30 and the frame holding portion 40 are moved in an axial direction perpendicular to the front surface 206 of the workpiece 201. More specifically, the control unit 80 raises the lifting member 51 and the chuck table 30 integrally through the worktable lifting unit 53 of the chip spacing forming unit 50. At this time, since the outer peripheral portion of the expansion piece 211 is fixed between the frame mounting plate 41 and the frame pressing plate 42, the annular region 212 of the expansion piece 211 is expanded in the surface direction. In addition, since the roller member 511 provided at the upper end of the lifting member 51 alleviates the friction with the expansion piece 211, the expansion piece 211 as a whole is expanded in the surface direction. In the expansion step ST2, as a result of the expansion of the expansion piece 211, a tensile force is applied radially to the expansion piece 211.

[0068] When a tensile force is applied radially to the expansion sheet 211 attached to the back surface 207 of the workpiece 201, the workpiece 201 Figure 2 The workpiece 201 is divided along the planned dividing line 204, starting from the modified layer 208 shown. This creates spaces between the devices 205, and the workpiece 201 is divided into a plurality of chips 202. At this time, since the annular region 212 of the expansion sheet 211 is harder than the region attached to the workpiece 201, the expansion of the annular region 212 of the expansion sheet 211 is suppressed, thereby promoting the expansion of the region attached to the workpiece 201.

[0069] As described above, in the method for processing the workpiece 201 of the embodiment, the expansion sheet 211 surrounding the workpiece 201 is heated until it is denatured and hardened compared to before the heating before the expansion sheet 211 is expanded. This promotes the expansion of the area attached to the workpiece 201.

[0070] [First Modification]

[0071] Next, a method for processing the workpiece 201 according to a first modified example of the present invention will be described with reference to the drawings. Figure 9 1 is a perspective view showing a configuration example of a heating and cooling unit 60-2 of an expansion device 10-2 used in a method for processing a workpiece 201 according to a first modification. Figure 9 In the embodiment, the same parts as those in the embodiment are denoted by the same reference numerals and description thereof is omitted.

[0072] Extension device 10-2 for a method of processing a workpiece 201 according to a first variation and Figure 3 and Figure 4 Compared to the expansion device 10 of the illustrated embodiment, the expansion device 10 includes a heating and cooling unit 60-2 in place of the heating unit 60. Like the heating unit 60, the heating and cooling unit 60-2 includes a unit body 61, a heat source 62, a rotating unit 63, and a lifting unit 64. The structure of the unit body 61, heat source 62, rotating unit 63, and lifting unit 64 of the heating and cooling unit 60-2 is identical to that of the heating unit 60, and therefore, description thereof will be omitted. The heating and cooling unit 60-2 differs from the heating unit 60 in that it includes a cooling fan 65.

[0073] The cooling fans 65 are arranged at equal intervals along the circumferential direction on the outer edge of the unit body 61. The cooling fans 65 are arranged at a position vertically opposite the annular area 212, wherein the annular area 212 is the area between the inner edge of the annular frame 210 of the expansion piece 211 of the frame unit 200 held by the chuck table 30 and the frame holding portion 40 and the outer edge of the workpiece 201. The cooling fans 65 blow air downward to locally cool the area between the inner edge of the annular frame 210 of the expansion piece 211 and the outer edge of the workpiece 201. In the first variant, four cooling fans 65 are provided, but the present invention is not limited to four. In addition, in the first variant, the cooling fans 65 are arranged alternately with the heat source portion 62 along the circumferential direction on the outer edge of the unit body 61, but the present invention is not limited to this.

[0074] In the thermal curing step ST1 of the first modification, Figure 6The thermal curing step ST1 of the embodiment shown in the figure is the same as that of the embodiment shown in the figure. First, the expansion sheet 211 around the workpiece 201 is heated to a predetermined temperature or higher. Then, in the embodiment, as shown in the figure, Figure 7 As shown, the workpiece 201 is cooled by being exposed to room temperature for a predetermined period of time. However, in the first modified example, the workpiece 201 is actively cooled. Specifically, the control unit 80 first stops heating by the heat source 62 of the heating-cooling unit 60-2. Next, while the heat source 62 of the heating unit 60 is positioned close to the annular region 212 of the expansion plate 211, the control unit 80 applies a voltage to the cooling fan 65 of the heating-cooling unit 60-2, thereby causing the cooling fan 65 to blow air. In the method for processing the workpiece 201 of the first modified example, the workpiece 201 is actively cooled by the air blown by the cooling fan 65, thereby shortening the time required for the thermal curing step ST1.

[0075] Furthermore, after performing the thermal curing step ST1 of the first modified example and before performing the expansion step ST2, the control unit 80 raises the unit body 61 of the heating and cooling unit 60-2 via the lifting unit 64. Alternatively, the control unit 80 may simultaneously raise the unit body 61 of the heating and cooling unit 60-2 when raising the lift member 51 and the chuck table 30 in the expansion step ST2.

[0076] [Second Modification]

[0077] Next, a method for processing the workpiece 201 - 2 according to a second modified example of the present invention will be described with reference to the drawings. Figure 10 2 is a top view showing an example of a workpiece 201-2 to be processed by a method for processing the workpiece 201-2 according to the second modified example. Figure 10 In the embodiment, the same parts as those in the embodiment are denoted by the same reference numerals and description thereof is omitted.

[0078] The workpiece 201-2 is divided into individual chips 202 along predetermined dividing lines 204, starting from the modified layer 208. The device 205 of the workpiece 201-2 is formed in a rectangular shape. The device 205 is formed so that its length 214 in the longitudinal direction is longer than its length 215 in the lateral direction. The number of predetermined dividing lines 204 in the workpiece 201-2 that are parallel to a first direction 221 parallel to the longitudinal direction of the device 205 is greater than the number of predetermined dividing lines 204 that are parallel to a second direction 222 parallel to the lateral direction of the device 205. When the expansion sheet 211 is expanded, the chips 202 are separated from each other in a direction perpendicular to the predetermined dividing lines 204. Therefore, the expansion amount of the expansion sheet 211 in the direction perpendicular to the plurality of predetermined dividing lines 204 increases. In the frame unit 200 having the workpiece 201-2 of the second modified example, the number of planned dividing lines 204 perpendicular to the second direction 222 is greater in the expansion piece 211 than the number of planned dividing lines 204 perpendicular to the first direction 221. Therefore, the expansion amount of the expansion device 10 in the second direction 222 is greater than the expansion amount in the first direction 221.

[0079] Therefore, in the thermal curing step ST1 of the workpiece 201-2 of the second modified example, the control unit 80 first heats the portions of the annular region 212 of the expansion sheet 211 located at both ends in the second direction 222 to a temperature above a predetermined temperature using the heating unit 60. Specifically, the control unit 80 causes the heating unit 60 to heat the region of the expansion sheet 211 that overlaps the direction in which it is desired to expand more than in other directions. Next, the control unit 80 cools the portions of the expansion sheet 211 located at both ends in the second direction 222 surrounding the workpiece 201, thereby hardening the portions relative to those before heating. By hardening the portions of the annular region 212 of the expansion sheet 211 located at both ends in the second direction 222 relative to the rest of the workpiece, the expansion of the annular region 212 of the expansion sheet 211 in the second direction 222 is suppressed. Thus, in the processing method of the workpiece 201-2 of the second modified example, the expansion of the region attached to the workpiece 201 in the second direction 222 can be promoted.

[0080] [Third Modification]

[0081] Next, a method for processing the workpiece 201 - 3 according to a third modified example of the present invention will be described with reference to the drawings. Figure 11 This is a cross-sectional view of a main portion of the workpiece 201-3 in which the interval between the chips 202 is enlarged by the processing method of the workpiece 201-3 according to the third modified example. Figure 11 In the embodiment, the same parts as those in the embodiment are denoted by the same reference numerals and description thereof is omitted.

[0082] The workpiece 201-3 of the third modified example is divided into individual chips 202 by forming dividing grooves 216 between the devices 205. The dividing grooves 216 can be formed along the dividing lines 204 (see FIG. Figure 1 or Figure 10 ) is formed by irradiating a laser beam with a wavelength that is absorptive to the workpiece 201-3 to perform ablation processing, or by cutting along the predetermined dividing line 204 to perform cutting processing.

[0083] In the thermal curing step ST1 of the third modified example, similar to the thermal curing step ST1 of the first embodiment, the expansion sheet 211 surrounding the workpiece 201-3 is heated to a predetermined temperature or higher and then cooled to a temperature that is harder than before heating. The area surrounding the workpiece 201-3 of the expansion sheet 211 is harder than the area attached to the plurality of chips 202 and the area between the plurality of chips 202.

[0084] In the expansion step ST2, the chip spacing forming unit 50 (see Figure 4 The expansion sheet 211 of the frame unit 200 is expanded to increase the distance between the multiple chips 202 to a desired distance. At this time, the area surrounding the workpiece 201-3 on the expansion sheet 211 is harder than the area attached to the multiple chips 202 and the area between the multiple chips 202. Thus, in the processing method of the workpiece 201-3 of the third modified example, the expansion of the area surrounding the workpiece 201-3 on the expansion sheet 211 is suppressed, while the expansion of the area between the multiple chips 202 is promoted.

[0085] [Fourth Modification]

[0086] Next, a method for processing the workpiece 201 according to a fourth modified example of the present invention will be described with reference to the drawings. Figure 12 1 is a flow chart showing the process of a method for processing the workpiece 201 according to the fourth modified example. Figure 12 As shown, the processing method of the workpiece 201 includes a thermal hardening step ST1, an expansion step ST2, and a slack removal step ST3. That is, the processing method of the workpiece 201 of the fourth modification further includes a slack removal step ST3 in addition to the processing method of the workpiece 201 of the embodiment.

[0087] Figure 13 It shows Figure 12 1 is a cross-sectional view of a main portion of the expanding device 10 in one state in the slack removing step ST3 of the method for machining the workpiece 201. Figure 14 It shows Figure 12The slack removing step ST3 is a cross-sectional view of the main part of the expanding device 10 after the slack removing step ST3 of the processing method of the workpiece 201. The slack removing step ST3 is a step of heating and shrinking the expanding sheet 211 slack around the outer periphery of the workpiece 201 again after the expansion step ST2.

[0088] The slack removal step ST3 is continued by the expansion device 10 used in the heat curing step ST1 and the expansion step ST2 in the embodiment or the first modification. In the fourth modification, in the slack removal step ST3, the expansion of the expansion piece 211 needs to be maintained while the slack of the expansion piece 211 is being removed. Figure 8 After the expansion step ST2 shown, a tensile force is radially applied to the expansion piece 211. At this time, the cross section of the annular region 212 of the expansion piece 211 is linear from the lower surface of the annular frame 210 toward the upper surface of the roller member 511.

[0089] First, the control unit 80 drives the vacuum suction source to apply suction to the holding surface 31 of the chuck table 30. The chuck table 30 suctionally holds the back surface 207 of the workpiece 201 on the holding surface 31 via the expansion piece 211. Thus, the control unit 80 maintains the interval between the chips 202.

[0090] Next, the control unit 80 lowers the lift member 51 and the chuck table 30 integrally via the table lifting unit 53 of the chip spacing forming unit 50. At this time, since the outer periphery of the expansion piece 211 is fixed between the frame mounting plate 41 and the frame pressing plate 42, and the center of the expansion piece 211 is attracted and held, as shown in FIG. Figure 13 As shown, the expansion piece 211 generates a slack portion 213 in the annular region 212. At this time, the control unit 80 uses the lifting unit 64 to lower the unit body 61 of the heating unit 60 and the chuck table 30 simultaneously.

[0091] In the slack removal step ST3, the control unit 80 applies a voltage to the heat source portion 62 of the heating unit 60 to heat the heat source portion 62 again to a predetermined temperature. The predetermined temperature is a predetermined constant temperature and may not necessarily be the same as the heating temperature in the thermal hardening step ST1. The heated heat source portion 62 radiates infrared rays. Figure 13As shown, the control unit 80 causes the heat source portion 62 of the heating unit 60 to approach the annular region 212 of the expansion piece 211 to heat the heat again. The heating unit 60 rotates about its axis via the rotation unit 63, thereby causing the heat source portion 62 to move circumferentially within the annular region 212 of the expansion piece 211. At this time, the control unit 80 can also control the lifting unit 64 of the heating unit 60 based on conditions pre-set by the operator. For example, the control unit 80 can also appropriately adjust the distance between the heat source portion 62 and the expansion piece 211 to increase the amount of heat provided to areas with greater slack and reduce the amount of heat provided to areas with less slack.

[0092] In the slack removing step ST3, the control unit 80 causes the heating unit 60 to heat the annular region 212 of the expansion sheet 211 expanded in the expansion step ST2. Figure 14 As shown, the slack of the expansion piece 211 is removed by heating the slack portion 213 .

[0093] Once the slack in the expansion piece 211 has been removed, the slack removal step ST3 ends. After the slack removal step ST3, the control unit 80 raises the heating unit 60 and stops the heating and vacuum suction of the heat source 62. The control unit 80 releases the frame holding unit 40 from securing the annular frame 210. In the frame unit 200, by removing the slack in the expanded expansion piece 211, the spacing between the plurality of chips 202 can be maintained even when the suction of the holding surface 31 of the chuck table 30 is released.

[0094] As described above, in the fourth modified example of the processing method for the workpiece 201, the expansion piece 211, which has been slackened due to the expansion between the annular frame 210 on the periphery of the workpiece 201 and the plurality of chips 202, is reheated by the heating unit 60 to shrink the expansion piece 211, thereby removing the slack. In this case, the heat source 62 used for heating in the thermal curing step ST1 and the heat source 62 used for reheating in the slack removal step ST3 can be used in common, thereby ensuring that the heat source 62 is used without waste.

[0095] The present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the spirit of the present invention.

Claims

1. A method for processing a workpiece, wherein an expansion piece of a frame unit is expanded to divide the workpiece into individual chips or to increase the distance between chips, wherein the frame unit is formed by supporting a plate-shaped workpiece having a starting point for division formed along a predetermined dividing line or a plate-shaped workpiece to be divided into a plurality of chips in an opening of an annular frame using the thermosetting expansion piece, wherein: The processing method of the workpiece has the following steps: a heat curing step of heating the expansion sheet around the workpiece to a temperature above a predetermined temperature and then locally cooling the expansion sheet between the annular frame and the workpiece by blowing air through the expansion sheet with a cooling fan, thereby curing the expansion sheet around the workpiece compared to before heating; as well as The expansion step is to expand the expansion piece on the periphery of the workpiece in the surface direction after the thermal curing step is performed, thereby dividing the workpiece into chips or increasing the intervals between the chips.

2. A method for processing a workpiece, wherein an expansion piece of a frame unit is expanded to divide the workpiece into individual chips or to increase the distance between chips, wherein the frame unit is formed by supporting a plate-shaped workpiece having a starting point for division formed along a predetermined dividing line or a plate-shaped workpiece to be divided into a plurality of chips in an opening of an annular frame using the thermosetting expansion piece, wherein: The processing method of the workpiece has the following steps: a heat curing step of heating the expansion piece around the workpiece to a predetermined temperature or higher and then cooling the expansion piece so that the expansion piece around the workpiece is cured compared to before heating; as well as an expansion step, after the heat curing step is performed, expanding the expansion piece on the periphery of the workpiece in the surface direction to divide the workpiece into chips or to increase the intervals between the chips; The thermal curing step is performed in a region of the annular region of the expansion piece around the workpiece that overlaps with a direction in which the workpiece is intended to expand more than other directions.

3. The method for processing a workpiece according to claim 1 or 2, wherein: The expansion sheet includes a base material layer and an adhesive layer, and the base material layer or the adhesive layer is formed of a thermosetting resin.

4. The method for processing a workpiece according to claim 1 or 2, wherein: The workpiece processing method further comprises a slack removing step of heating the expansion piece that has been relaxed around the periphery of the workpiece again to shrink the expansion piece after the expansion step.

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