Method for processing a workpiece, hot press joining method

Abstract

A processing method of an object to be processed, a heat press bonding method, and a heat press bonding apparatus are provided. The processing method of the object to be processed includes a laminating step of laminating a sheet and a flat plate on a front surface of the object to be processed to form a laminate in which the sheet is sandwiched by the object to be processed and the flat plate; a heat press bonding step of heating the sheet and applying an external force to the laminate to flatten the sheet by the flat plate while heat press bonding the sheet to the object to be processed; a holding step of holding the object to be processed with a holding table having a transparent portion containing a transparent member, with the sheet interposed therebetween, after the heat press bonding step; an alignment step of performing alignment by photographing the object to be processed with the transparent portion and the sheet interposed therebetween, after the holding step; and a processing step of processing the object to be processed by a processing unit, after the alignment step.

Description

TECHNICAL FIELD

[0001] The present application relates to a processing method of processing a workpiece and a thermocompression bonding method of thermocompression bonding a sheet to a workpiece. BACKGROUND

[0002] In a manufacturing process of a device chip, a plurality of division predetermined lines (streets) intersecting each other are provided on a front surface of a substrate such as a semiconductor wafer or a package substrate, a ceramic substrate, a glass substrate, and a device is provided in each region of the front surface of the substrate divided by the division predetermined lines. When the substrate provided with the device is divided along the division predetermined lines, each device chip can be formed.

[0003] In the division of the substrate, a processing device such as a cutting device having a cutting tool capable of cutting the substrate along the division predetermined lines or a laser processing device capable of laser processing the substrate along the division predetermined lines is used. When the workpiece such as the substrate is carried into the processing device, a frame in a ring shape is prepared, and a tape is attached to the frame and the workpiece to form a frame unit in such a manner that the opening of the ring-shaped frame is closed. The tape has an adhesive layer having adhesiveness. The tape is attached to the frame and the workpiece by the adhesion of the adhesive layer.

[0004] The workpiece is carried into the processing device in the state of the frame unit and is processed. Further, each device chip formed by dividing the workpiece is held to the tape. Then, the device chip is peeled from the tape and mounted to a prescribed mounting object.

[0005] After the device chip is peeled from the tape, a part of the adhesive layer of the tape sometimes remains on the device chip, which becomes a cause of generation of a defective device chip. Therefore, in order to prevent the generation of the residue of the adhesive layer, a sheet is proposed which does not have an adhesive layer in a region corresponding to a device region of a front surface of a workpiece in which a device is formed and has an adhesive layer in a region corresponding to a peripheral remaining region of a periphery of the device region (for example, refer to Patent Literature 1). In the case of using the sheet, the sheet is made to adhere to the device region of the workpiece to form the frame unit.

[0006] However, when the workpiece is processed, the tape is sometimes attached to the front surface side in which the device is formed and the workpiece is processed from the back surface side. In this case, when the frame unit is held to a holding worktable of the processing device, the back surface side of the workpiece is made to be exposed upward. Further, in order to confirm the processing site of the workpiece, a device capable of photographing the front surface side of the workpiece through the holding worktable from the lower side is proposed (for example, refer to Patent Literature 2).

[0007] Patent Literature 1: Japanese Patent Application Laid-Open No. 2013-243311

[0008] Patent Literature 2: Japanese Patent Application Laid-Open No. 2010-82644

[0009] When the frame unit is formed using the sheet that does not have the adhesive layer in the region corresponding to the device region, the residue of the adhesive layer does not remain on the device chip when the object having the concave-convex on the front surface is processed. On the other hand, the concave portion of the front surface of the object does not come into close contact with the sheet, and thus a space is formed between the sheet and the object.

[0010] In this state, the lower surface side (front surface side) of the object cannot be sufficiently supported, and thus when the object is cut in this state, there is a possibility that a chipping or a crack is formed in the device chip. In addition, the device chip formed by dividing the object can be peeled off from the sheet and scattered. In addition, cutting water containing cutting chips generated by cutting can enter the space between the sheet and the object and contaminate the front surface of the object.

[0011] In addition, when the sheet is brought into close contact with the object having the concave-convex on the front surface, a step that imitates the concave-convex of the object is generated on the surface of the holding table of the sheet that is held (the surface that does not come into abutment with the object). In addition, sometimes the surface of the sheet that does not come into abutment with the object is subjected to processing that becomes a pear skin surface in advance. Thus, even when the front surface of the object is observed through the sheet from the holding table side that holds the object, there is a case where the light is disturbed by the sheet and the captured image is unclear, and thus the processing unit cannot be positioned properly. SUMMARY

[0012] The present application has been achieved in view of the problem, and an object thereof is to provide a processing method of an object and a thermocompression bonding method, which can bring the object and a sheet into close contact and can flatten the surface of the sheet that does not come into abutment with the object.

[0013] According to one embodiment of the present application, there is provided a processing method of an object, characterized by comprising: a lamination step of laminating a sheet and a flat plate on a front surface of the object to form a laminate in which the sheet is sandwiched by the object and the flat plate; a thermocompression bonding step of flattening the sheet with the flat plate by heating the sheet and applying an external force to the laminate while thermocompression bonding the sheet to the object; a holding step of holding the object with a holding table having a transparent portion containing a transparent member, through the sheet, after the thermocompression bonding step; an alignment step of performing alignment by capturing the object through the transparent portion and the sheet, after the holding step; and a processing step of processing the object with a processing unit, after the alignment step.

[0014] Preferably, the workpiece has unevenness on the front surface, the sheet has a thickness larger than a height difference of the unevenness, in the layering step, the sheet is layered on the front surface of the workpiece, in the heat pressure bonding step, the sheet is heat pressure bonded on the front surface of the workpiece, in the holding step, the front surface side of the workpiece is held with the holding table through the sheet, and in the processing step, the workpiece is processed from the back surface side of the workpiece with the processing unit.

[0015] Further, preferably, the workpiece has a device region in which a plurality of devices are formed on the front surface, and the sheet has an adhesive layer in a region not corresponding to the device region of the workpiece.

[0016] Further, according to another aspect of the present application, there is provided a heat pressure bonding method of heat pressure bonding a sheet on a workpiece, characterized by comprising: a layering step of layering the sheet and a flat plate on a front surface of the workpiece to form a layered body in which the sheet is sandwiched by the workpiece and the flat plate; and a heat pressure bonding step of, after the layering step is performed, planarizing the sheet with the flat plate by heating the sheet and applying an external force to the layered body while heat pressure bonding the sheet on the workpiece.

[0017] In the processing method and the heat pressure bonding method of one aspect of the present application, a sheet and a flat plate are layered on a workpiece, and a sheet is heat pressure bonded on a workpiece. Thus, a surface of the sheet which does not abut against the workpiece becomes planar. Further, even if unevenness is formed on the front surface of the workpiece, a space between the sheet and the workpiece is filled with the sheet, so that the workpiece is firmly attached to the sheet.

[0018] Therefore, according to the present application, there are provided a processing method and a heat pressure bonding method of a workpiece, which can attach a workpiece and a sheet, and can planarize a surface of the sheet which does not abut against the workpiece. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a perspective view schematically showing a workpiece.

[0020] Figure 2 is a cross-sectional view schematically showing a workpiece having unevenness on a front surface, enlarged.

[0021] Figure 3 is a cross-sectional view schematically showing an example of a heat pressure bonding apparatus and an example of a heat pressure bonding step.

[0022] Figure 4 (A) of FIG. 1 is a cross-sectional view schematically showing another example of a heat pressure bonding apparatus, Figure 4 (B) of FIG. 1 is a cross-sectional view schematically showing another example of a heat pressure bonding step.

[0023] Figure 5 (B) is a cross-sectional view schematically showing another example of the laser processing apparatus and the workpiece. Figure 5 (B) is a cross-sectional view schematically showing another example of the laser processing apparatus and the workpiece.

[0024] Figure 6 (B) is a cross-sectional view schematically showing another example of the laser processing apparatus and the workpiece.

[0025] Figure 7 (B) is a cross-sectional view schematically showing another example of the laser processing apparatus and the workpiece.

[0026] Figure 8 (B) is a cross-sectional view schematically showing another example of the laser processing apparatus and the workpiece.

[0027] Figure 9 (A) is a cross-sectional view schematically showing an example of the alignment step, Figure 9 (B) is a cross-sectional view schematically showing an example of the processing step.

[0028] Figure 10 (B) is a cross-sectional view schematically showing another example of the laser processing apparatus and the workpiece.

[0029] Figure 11 (B) is a cross-sectional view schematically showing another example of the laser processing apparatus and the workpiece.

[0030] Figure 12 (A) is a cross-sectional view schematically showing an example of the alignment step, Figure 12 (B) is a cross-sectional view schematically showing another example of the processing step.

[0031] Explanation of Reference Signs

[0032] 1: object to be processed; 1a: front surface; 1b: back surface; 3: division line; 3a: modified layer; 5: device; 7: sheet; 9: flat plate; 11: metal layer; 13a: convex portion; 13b: concave portion; 15: adhesive layer; 17: frame; 2, 2a, 2b: heat press device; 4, 4b: worktable frame; 6, 6b: porous member; 8, 8b: suction path; 10, 10b: suction source; 12, 12b, 66: switching valve; 14, 14a, 14b: heater; 16: laser processing device; 18, 72: base; 20, 30, 74, 84, 102: guide rail; 22, 76: moving worktable; 24, 34, 78, 88, 106: ball screw; 26, 36, 80, 90, 108: pulse motor; 28, 38, 82, 92: scale; 32, 86: worktable base; 32a, 86a: side plate portion; 32b, 86b: bottom plate portion; 32c, 86c: top plate portion; 32d, 86d: space; 34a, 88a: nut portion; 40, 94: holding worktable; 40a, 94a: holding member; 40b, 94b: pulley portion; 40c, 94c: suction path; 40d: suction groove; 94d: fine hole; 40e, 94e: fitting convex portion; 40f, 94f: suction portion; 40g, 94g: transparent portion; 42, 96: belt; 44, 98: rotary drive source; 44a, 98a: pulley; 46, 116: frame placement portion; 48, 100: support structure; 50: laser processing unit; 50a: laser beam; 50b: condensing point; 52, 120: upper photographing unit; 54, 110: lower photographing unit; 56, 112: lifting support mechanism; 58, 114: arm portion; 60: frame support table; 62: lifting worktable; 64: air passage; 66: switching valve; 68: pressurizing unit; 70: cutting device; 104: main shaft housing; 118: cutting unit; 118a: cutting tool; 118b: main shaft. DETAILED DESCRIPTION

[0033] An embodiment of one mode of the present application will be described with reference to the drawings. In the processing method of the object to be processed and the heat press method of the present embodiment, a sheet and a flat plate are stacked on an object to be processed, forming a stack in which the sheet is sandwiched by the object to be processed and the flat plate. Then, the sheet is heated and an external force is applied to the stack to flatten the sheet using the flat plate, while the sheet is heat-pressed on the object to be processed.

[0034] First, a processing method of an object to be processed will be described. Figure 1 The object to be processed 1 is, for example, a material such as silicon, SiC (silicon carbide), or other semiconductors, or a complex oxide such as lithium tantalate (LT) and lithium niobate (LN). Or the object to be processed 1 is a substrate composed of a material such as sapphire, glass, quartz, or ceramic, or the object to be processed 1 is a packaging substrate on which a device is covered with resin.

[0035] Multiple intersecting pre-defined dividing lines 3 are provided on the front side 1a of the workpiece 1. Devices 5 such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are provided in each area divided by the pre-defined dividing lines 3. When the workpiece 1 is divided along the pre-defined dividing lines 3, individual device chips can be formed.

[0036] In addition, the workpiece 1 may have irregularities on its front side 1a. Figure 2 This is a schematic cross-sectional view of a workpiece 1 having irregularities on its front surface 1a. For example, a device 5 is formed in the area divided by a predetermined dividing line 3 on the front surface 1a of the workpiece 1. The workpiece 1 has, for example, a protrusion 13a on its front surface 1a, and a recess 13b around the protrusion 13a. Furthermore, in the following figures, the protrusion 13a and the recess 13b of the front surface 1a of the workpiece 1 are omitted.

[0037] like Figure 2 As shown, a metal layer 11 can be formed on the back side 1b of the workpiece 1. The metal layer 11 functions, for example, as an electrode or heat sink for a device chip formed by dividing the workpiece 1. However, when the metal layer 11 is formed on the back side 1b of the workpiece 1, it is difficult to determine the position of the predetermined dividing line 3 on the front side 1a by photographing the workpiece 1 from the back side 1b using an infrared camera or the like.

[0038] Next, use Figure 3 Explanation of the film. In Figure 3 The diagram schematically shows a cross-sectional view of sheet 7 held between workpiece 1 and plate 9. Sheet 7 is a sheet made of thermoplastic resin that softens through heat, and is transparent or translucent to visible light. Sheet 7 is, for example, a sheet of polyvinyl chloride, a polyolefin-based sheet, or a polyester-based sheet. Polyolefin-based sheets include, for example, polyethylene sheets, polypropylene sheets, polystyrene sheets, etc.

[0039] The surface of sheet 7 that contacts the workpiece 1 is flat. However, sometimes the surface of sheet 7 that does not contact the workpiece 1 is processed with a pear-skin finish. However, this embodiment is not limited to this; sheet 7 can be flat on both sides or pear-skin on both sides.

[0040] The planar shape of sheet 7 is such that it can cover the workpiece 1. For example, it is approximately the same as the planar shape of the front surface 1a of the workpiece 1. Sheet 7 may have an adhesive layer in a region that does not correspond to the device region of the workpiece 1 where the device 5 is formed. In other words, it may have an adhesive layer in a region that corresponds to the remaining area of ​​the outer periphery of the workpiece 1 surrounding the device region.

[0041] In addition, the planar shape of the sheet 7 can be larger than the planar shape of the front face la of the workpiece 1. In this case, when an adhesive layer 15 (see (A) and the like of FIG. 1) is formed on the outer peripheral portion of the sheet 7, the sheet 7 can be adhered to a ring-shaped frame 17 (see (A) and the like of FIG. 1) by the adhesive layer 15. Here, the frame 17 has an opening with a diameter larger than the diameter of the workpiece 1, and is formed of a material such as metal, for example. In addition, in the case where the sheet 7 does not have the adhesive layer 15, the sheet 7 can be thermocompression-bonded to the frame 17 together with the workpiece 1. Figure 4 In addition, the planar shape of the sheet 7 can be larger than the planar shape of the front face la of the workpiece 1. In this case, when an adhesive layer 15 (see (A) and the like of FIG. 1) is formed on the outer peripheral portion of the sheet 7, the sheet 7 can be adhered to a ring-shaped frame 17 (see (A) and the like of FIG. 1) by the adhesive layer 15. Here, the frame 17 has an opening with a diameter larger than the diameter of the workpiece 1, and is formed of a material such as metal, for example. In addition, in the case where the sheet 7 does not have the adhesive layer 15, the sheet 7 can be thermocompression-bonded to the frame 17 together with the workpiece 1. Figure 4 In addition, the planar shape of the sheet 7 can be larger than the planar shape of the front face la of the workpiece 1. In this case, when an adhesive layer 15 (see (A) and the like of FIG. 1) is formed on the outer peripheral portion of the sheet 7, the sheet 7 can be adhered to a ring-shaped frame 17 (see (A) and the like of FIG. 1) by the adhesive layer 15. Here, the frame 17 has an opening with a diameter larger than the diameter of the workpiece 1, and is formed of a material such as metal, for example. In addition, in the case where the sheet 7 does not have the adhesive layer 15, the sheet 7 can be thermocompression-bonded to the frame 17 together with the workpiece 1.

[0042] The sheet 7 has no adhesiveness and cannot be adhered to the workpiece 1 at room temperature. However, when the workpiece 1 and the sheet 7 are brought into contact with each other, the sheet 7 is heated to be softened, and a predetermined external force is applied to the sheet 7 and the workpiece 1, the sheet 7 can be tightly adhered to the workpiece 1. That is, the sheet 7 can be thermocompression-bonded to the workpiece 1. In addition, in order to tightly adhere the sheet 7 to the front face la of the workpiece 1, it is preferable that the sheet 7 has a thickness larger than the height difference of the irregularities of the workpiece 1.

[0043] Next, the flat plate 9 used when the sheet 7 is thermocompression-bonded to the workpiece 1 will be described. Figure 3 The flat plate 9 is a plate-shaped member having flat surfaces on both sides. The size of the flat plate 9 is a size capable of covering the entire sheet 7, and is, for example, a planar shape identical to the planar shape of the sheet 7.

[0044] When the sheet 7 is heated to be softened, the flat plate 9 in contact with the sheet 7 is also heated, but the flat plate 9 is formed of a material harder than the sheet 7 in this state. That is, the flat plate 9 is formed of a material having a higher softening point (temperature at which softening begins) or melting point than the sheet 7. The flat plate 9 is formed of, for example, a resin such as polyethylene terephthalate (PET) or glass, metal, or the like.

[0045] Next, a thermocompression-bonding device (heating device) used in the workpiece processing method and the thermocompression-bonding method of the present embodiment will be described. Figure 3 is a cross-sectional view schematically showing an example of a thermocompression-bonding device (heating device). Figure 3 The thermocompression-bonding device 2 shown in FIG. 2 is a table-like device that supports the workpiece 1.

[0046] The thermocompression-bonding device 2 has a table frame 4 formed with a recess on the upper surface and made of a metal material typified by stainless steel, and a porous member 6 housed in the recess of the table frame 4. The porous member 6 has a diameter substantially identical to the diameter of the workpiece 1. An attraction path 8 that communicates with the porous member 6 is formed in the inside of the table frame 4. That is, one end of the attraction path 8 communicates with the porous member 6.

[0047] An attraction source 10 is connected via a switching valve 12 at the other end side of the attraction path 8. When the workpiece 1 is placed on the porous member 6 and the switching valve 12 is operated to connect the attraction source 10 to the attraction path 8, the negative pressure generated by the attraction source 10 acts on the workpiece 1 through the attraction path 8 and the porous member 6, and the workpiece 1 is attracted and held by the heat press device 2.

[0048] A heater 14 that heats an object placed on the heat press device 2 is also formed inside the table frame 4. The heater 14 is, for example, an electric heater. When the workpiece 1 is attracted and held by the heat press device 2, the sheet 7 and the flat plate 9 are stacked on the workpiece 1, and the heater 14 is operated, the sheet 7 is heated by the workpiece 1. When the heater 14 is operated to raise the temperature of the sheet 7 to above the softening point and the flat plate 9 is pressed from above, the sheet 7 and the workpiece 1 can be heat-pressed.

[0049] In addition, the heat press device used in the workpiece processing method and the heat press method of the present embodiment is not limited to this. In Figure 4 (A) and Figure 4 (A) and Figure 4 (A) and Figure 4 (A) and

[0050] The heat press device 2a has a housing that can form a closed space inside, and has a cylindrical frame support table 60 that supports the frame 17 inside the housing, and a lifting table 62 that is fitted into an opening of the frame support table 60. The lifting table 62 can be lifted and lowered with respect to the frame support table 60. A heater 14a is assembled inside the lifting table 62. The space inside the housing of the heat press device 2a is divided into an upper workpiece 1 placement space and a lower pressure raising space by the frame support table 60 and the lifting table 62.

[0051] A ventilation path 64 that communicates the inside and outside of the cylindrical frame support table 60 is formed in the lower portion of the frame support table 60. A through hole is formed in the housing of the heat press device 2a at a position corresponding to the ventilation path 64 of the frame support table 60. One end of the ventilation path 64 communicates with the pressure raising space inside the housing, and a switching valve 66 is connected to the other end of the ventilation path 64. The switching valve 66 has a function of selectively connecting one of the outside space of the heat press device 2a or a pressure raising unit 68 to the ventilation path 64. The pressure raising unit 68 is, for example, an air compressor.

[0052] When the hot press bonding device 2a is used, the workpiece 1, the frame 17, the sheet 7, and the flat plate 9 are carried into the placement space inside the housing. Also, the workpiece 1 is placed on the elevating table 62 with the back surface Ib facing downward, and the frame 17 is placed on the frame support table 60. In addition, the sheet 7 and the flat plate 9 are stacked on the frame 17 and the workpiece 1.

[0053] Next, the switching valve 66 is operated to connect the pressurizing unit 68 to the pressure-boosting space of the hot press bonding device 2a through the vent passage 64, and the pressure of the pressure-boosting space is increased. Then, as shown in (B) of FIG. 6, the elevating table 62 is raised to make the front surface la side of the workpiece 1 adhere to the sheet 7. When the workpiece 1 is pressed toward the sheet 7 by the elevating table 62, and the temperature of the sheet 7 is increased to above the softening point by the operation of the heater 14a while heating the sheet 7 through the workpiece 1, the sheet 7 and the workpiece 1 can be hot press bonded. Figure 4

[0054] Then, when the switching valve 66 is operated to connect the pressure-boosting space of the hot press bonding device 2a to the outside space of the hot press bonding device 2a, the pressure of the pressure-boosting space is decreased, and the elevating table 62 is lowered. At this time, the workpiece 1 has been hot press bonded to the sheet 7, and thus the workpiece 1 is in a state of floating with respect to the elevating table 62.

[0055] The hot press bonding device used in the workpiece processing method and the hot press bonding method of the present embodiment is not limited to this. In the hot press bonding device shown in (A) of FIG. 1 and (B) of FIG. 2, the elevating table 62 is raised to make the front surface la side of the workpiece 1 adhere to the sheet 7. Then, the workpiece 1 is pressed toward the sheet 7 by the elevating table 62, and the temperature of the sheet 7 is increased to above the softening point by the operation of the heater 14a while heating the sheet 7 through the workpiece 1. Thus, the sheet 7 and the workpiece 1 can be hot press bonded. Figure 5 Figure 5 (A) of FIG. 1 and (B) of FIG. 2, the elevating table 62 is raised to make the front surface la side of the workpiece 1 adhere to the sheet 7. Then, the workpiece 1 is pressed toward the sheet 7 by the elevating table 62, and the temperature of the sheet 7 is increased to above the softening point by the operation of the heater 14a while heating the sheet 7 through the workpiece 1. Thus, the sheet 7 and the workpiece 1 can be hot press bonded. Figure 5 Figure 5 (A) of FIG. 1 and (B) of FIG. 2, the elevating table 62 is raised to make the front surface la side of the workpiece 1 adhere to the sheet 7. Then, the workpiece 1 is pressed toward the sheet 7 by the elevating table 62, and the temperature of the sheet 7 is increased to above the softening point by the operation of the heater 14a while heating the sheet 7 through the workpiece 1. Thus, the sheet 7 and the workpiece 1 can be hot press bonded.

[0056] The hot press bonding device 2b has a table frame 4b and a porous member 6b. The porous member 6b has a diameter larger than the inner diameter of the frame 17 integrated with the workpiece 1 and smaller than the outer diameter of the frame 17. An attraction passage 8b communicating with the porous member 6b is formed inside the table frame 4b. An attraction source 10b is connected to the other end side of the attraction passage 8b through a switching valve 12b. A heater 14b is formed inside the table frame 4b.

[0057] The workpiece 1 and the frame 17 are placed on the hot press bonding device 2b with the back surface Ib side of the workpiece 1 facing downward, and the sheet 7 and the flat plate 9 are disposed above the workpiece 1 and the frame 17. At this time, the workpiece 1 and the sheet 7 can not be in contact. Then, the heater 14b is operated to heat the frame 17 and the workpiece 1. In this case, heat is transferred from the frame 17 to the sheet 7 to heat the sheet 7. At this time, the temperature of the sheet 7 is increased to above the softening point.​​​

[0058] And, as Figure 5 As shown in (B), when the switching valve 12b is activated to connect the suction source 10b with the suction path 8b, the space surrounded by the heat-pressing device 2b, the frame 17, and the sheet 7 is depressurized. In this case, the pressure difference between the inside and outside of the space presses the plate 9 downward, and the sheet 7 enters the opening of the frame 17 and adheres tightly to the front surface 1a of the workpiece 1, thereby heat-pressing the sheet 7 onto the workpiece 1.

[0059] Furthermore, the porous component 6b of the heat-pressing device 2b can have a diameter larger than the outer diameter of the frame 17. In this case, a sheet 7 with a diameter larger than that of the porous component 6b is prepared, and when the sheet 7 is placed on the workpiece 1 and the frame 17, the sheet 7 covers the entire upper surface of the porous component 6b. Thus, the negative pressure generated by the suction source 10b can reduce the pressure in the space surrounded by the heat-pressing device 2b and the sheet 7. Moreover, when the sheet 7 is cut in the area overlapping with the frame 17 after being heat-pressed onto the frame 17, a frame unit can be formed.

[0060] In addition, in the processing method and hot pressing method of the workpiece in this embodiment, a hot pressing device other than hot pressing devices 2, 2a, and 2b can be used.

[0061] Next, the processing apparatus used in the processing method of the workpiece in this embodiment will be described. When the workpiece 1 is processed and divided along the predetermined dividing line 3, individual device chips can be formed. This processing apparatus is a processing apparatus that processes the workpiece 1 along the predetermined dividing line 3.

[0062] When processing workpiece 1 using a processing apparatus, the position of the predetermined dividing line 3 is confirmed by photographing workpiece 1 using the imaging unit of the processing apparatus. Furthermore, the processing apparatus is aligned in such a way that workpiece 1 can be processed along the predetermined dividing line 3, and the position of the alignment adjustment unit is adjusted accordingly. The processing apparatus for processing workpiece 1 is, for example, a laser processing apparatus that irradiates workpiece 1 with a laser beam.

[0063] A laser processing apparatus irradiates a workpiece 1 with a laser beam of an absorptive wavelength (a wavelength that the workpiece 1 can absorb) to perform ablation processing, thereby forming a processing groove on the workpiece 1. Alternatively, the laser processing apparatus focuses a laser beam of a transmissible wavelength (a wavelength that can pass through the workpiece 1) into the interior of the workpiece 1 to form a modified layer within the workpiece 1. When an external force is applied to the workpiece 1 with the modified layer, cracks are generated from the modified layer upwards and downwards, thus dividing the workpiece 1.

[0064] As an example of a processing apparatus for processing workpiece 1, a laser processing apparatus will be described. Figure 6 This is a schematic perspective view of the laser processing apparatus 16. In the following description, the X-axis (processing feed direction), Y-axis (indexing feed direction), and Z-axis (height direction) are perpendicular to each other. Figure 6 As shown, the laser processing apparatus 16 has a base 18 that supports each of its constituent elements.

[0065] A pair of X-axis guide rails 20, approximately parallel to the X-axis direction, are fixed on the upper surface of the base 18. The X-axis movable stage 22 is slidably mounted on the X-axis guide rails 20. A nut portion (not shown) is provided on the lower surface of the X-axis movable stage 22, in which an X-axis ball screw 24, approximately parallel to the X-axis guide rails 20, is screwed.

[0066] An X-axis pulse motor 26 is connected to one end of the X-axis ball screw 24. If the X-axis ball screw 24 is rotated using the X-axis pulse motor 26, the X-axis moving table 22 moves along the X-axis guide rail 20 in the X-axis direction. An X-axis scale 28, used for detecting the position of the X-axis moving table 22 in the X-axis direction, is provided adjacent to the X-axis guide rail 20.

[0067] A pair of Y-axis guide rails 30, approximately parallel to the Y-axis direction, are provided on the upper surface of the X-axis moving stage 22. The stage base 32 is slidably mounted on the Y-axis guide rails 30. Figure 7 The diagram schematically shows a cross-sectional view of the worktable base 32. A nut portion 34a is provided on the lower surface of the base plate portion 32b of the worktable base 32, in which a Y-axis ball screw 34, substantially parallel to the Y-axis guide rail 30, is screwed. A Y-axis pulse motor 36 is connected to one end of the Y-axis ball screw 34.

[0068] If the Y-axis ball screw 34 is rotated by the Y-axis pulse motor 36, the worktable base 32 moves along the Y-axis guide rail 30 in the Y-axis direction. A Y-axis scale 38 is provided adjacent to the Y-axis guide rail 30 for detecting the position of the worktable base 32 in the Y-axis direction.

[0069] A rectangular side plate portion 32a is connected to one end of the base plate portion 32b of the workbench base 32 in the Y-axis direction. A rectangular top plate portion 32c, similar in shape to the base plate portion 32b, is connected to the upper end of the side plate portion 32a in the Y-axis direction. That is, a space 32d is formed between the base plate portion 32b and the top plate portion 32c, connecting to the outside at the other end in the Y-axis direction and both ends in the X-axis direction.

[0070] A holding table (chuck table) 40 for holding the workpiece 1 is disposed on the upper surface of the top plate portion 32c of the table base 32. This holding table 40 is supported on the top plate portion 32c of the table base 32 in a manner that allows it to rotate about a rotation axis substantially parallel to the Z-axis direction. Figure 8 As shown, an annular fitting hole is formed on the top plate portion 32c, and an annular fitting protrusion 40e is slidably inserted into the fitting hole. Furthermore, when the holding table 40 is rotated, the fitting protrusion 40e slides relative to the fitting hole.

[0071] The holding stage 40 has a disc-shaped holding member 40a on its upper surface for attracting and holding the workpiece 1. The holding member 40a is made of a transparent material that transmits visible light, such as soda-lime glass, borosilicate glass, or quartz glass. The holding member 40a has an attracting portion 40f and a transparent portion 40g surrounded by the attracting portion. Figure 6 In the laser processing apparatus 16 shown, the transparent portion 40g is formed into an X-shape having portions along the X-axis and Y-axis directions.

[0072] Inside the retaining component 40a, there is a suction path 40c for attracting the workpiece 1 (see reference). Figure 8 Furthermore, a plurality of suction grooves 40d are formed in the suction portion 40f of the retaining member 40a (see reference). Figure 8 At the other end of the suction path 40c, there is a suction source (not shown) containing an injector or the like.

[0073] The transparent portion 40g of the holding member 40a is transparent from its upper surface to its lower surface. This allows for the imaging of the workpiece 1, etc., disposed on the upper surface of the holding member 40a, from the lower surface side. Furthermore, in this embodiment, a holding member 40a entirely composed of a transparent component is shown; however, the holding member 40a only needs to have a transparent portion 40g that is transparent from its upper surface to its lower surface. That is, the holding member 40a may not be composed of only a transparent component. Additionally, an opening (not shown) is formed on the top plate portion 32c in the area overlapping with the transparent portion 40g.

[0074] A rotary drive source 44, such as an electric motor, is provided on the side plate portion 32a of the worktable base 32. A belt 42 for transmitting power from the rotary drive source 44 is attached to the pulley portion 40b provided on the outer periphery of the holding worktable 40 and the pulley 44a connected to the rotation shaft of the rotary drive source 44. Therefore, the holding worktable 40 rotates about an axis that is approximately parallel to the Z-axis direction by the force transmitted from the rotary drive source 44 via the belt 42.

[0075] In addition, a plurality of columnar frame placement portions 46 that place the annular frame 17 are provided on the top plate portion 32c on the outer side of the holding stage 40. The plurality of frame placement portions 46 place the frame 17 in a manner that does not interfere with the rotation of the holding stage 40. In addition, the holding stage 40 moves in the X-axis direction or the Y-axis direction with the X-axis moving stage 22 or the stage base 32 as a power source, using the X-axis pulse motor 26 and the Y-axis pulse motor 36 described above.

[0076] As shown in FIG. 1, a columnar or wall-like support structure 48 is provided on the rear portion of the upper surface of the base 18. An arm portion that extends from the upper end of the support structure 48 to above the holding stage 40 in the Y-axis direction is provided on the upper end of the support structure 48, and a laser processing unit 50 that performs laser processing on the workpiece 1 held by the holding stage 40 is provided on the front end of the arm portion. In addition, an upper portion photographing unit 52 that photographs the workpiece 1 from above is fixed to the front end of the arm portion adjacent to the laser processing unit 50. Figure 6

[0077] The laser processing unit 50 is composed of a laser oscillator and optical components. The laser processing unit 50 can irradiate a laser beam of a wavelength that is absorbable by the workpiece 1 (a wavelength that can be absorbed by the workpiece 1) to the workpiece 1 held by the holding stage 40 to perform ablation processing, and form a processing groove along the division predetermined line 3 on the workpiece 1.

[0078] Alternatively, the laser processing unit 50 can focus a laser beam of a wavelength that is transmittable through the workpiece 1 (a wavelength that can be transmitted through the workpiece 1) to the inside of the workpiece 1 to form a modified layer in the workpiece 1 along the division predetermined line 3. Hereinafter, a case in which the laser processing unit 50 performs laser processing to form a modified layer in the inside of the workpiece 1 in the laser processing device 16 will be described, but the processing performed by the laser processing device 16 can be ablation processing.

[0079] A columnar lift support mechanism 56 is also provided on the rear portion of the upper surface of the base 18. In Figure 7 A side view of the lift support mechanism 56 is schematically shown in FIG. 2. The lift support mechanism 56 supports the lower photographing unit 54 so as to be liftable. The base end side of an arm portion 58 that is long in the Y-axis direction is connected to the lift plate of the lift support mechanism 56, and the lower photographing unit 54 is fixed to the front end of the arm portion 58. The lower photographing unit 54 includes a camera that photographs the workpiece 1 held by the holding stage 40, and an illumination portion (not shown) that irradiates light to the workpiece 1.

[0080] ​When the workpiece 1 is processed from the back surface 1b side by the laser processing device 16 thus configured, first, the sheet 7 attached to the front surface 1a side of the workpiece 1 is brought into contact with the front surface side of the holding member 40a of the holding table 40. Also, negative pressure of the suction source is applied from the plurality of suction grooves 40d corresponding to one end of the suction path 40c. Thus, the workpiece 1 is held in the state of being exposed upward at the back surface 1b side to the holding table 40.

[0081] Next, the table base 32 is moved to insert the lower photographing unit 54 into the space 32d between the bottom plate portion 32b and the top plate portion 32c of the table base 32. Also, the lower photographing unit 54 is disposed below the transparent portion 40g of the holding member 40a. The positional relationship of the holding member 40a and the lower photographing unit 54 is adjusted within a range suitable for photographing of the workpiece 1. In Figure 9 The positional relationship of the workpiece 1 and the lower photographing unit 54 when the front surface 1a (lower surface) side of the workpiece 1 is photographed by the lower photographing unit 54 is schematically shown in the cross-sectional view of (A).

[0082] As described above, the transparent portion 40g of the holding member 40a and the sheet 7 are transparent. Thus, if light is irradiated from the illumination portion of the lower photographing unit 54 toward the workpiece 1 upward and the light reflected on the front surface 1a side (lower surface side) of the workpiece 1 is received by the camera of the lower photographing unit 54, the front surface 1a side of the workpiece 1 can be photographed. When an image obtained by this photographing is used, the position of the division intended line 3 of the workpiece 1 (refer to Figure 1 ) can be determined, and alignment of the laser processing unit 50 can be performed.

[0083] Then, the workpiece 1 is subjected to laser processing. In Figure 9 The positional relationship of the workpiece 1 and the laser processing unit 50 when the laser processing is performed is schematically shown in the cross-sectional view of (B). First, the X-axis pulse motor 26 and the Y-axis pulse motor 36 are caused to act, and the position of the laser processing unit 50 is aligned above the extension line of the division intended line 3 as the processing target. Also, the focal point 50b is positioned at a prescribed height position inside the workpiece 1.

[0084] Then, while the laser beam 50a is irradiated to the inside of the workpiece 1, the holding table 40 is moved in the X-axis direction. Thus, the workpiece 1 can be subjected to laser processing along the division intended line 3 as the processing target, and a modified layer 3a can be formed inside the workpiece 1 along the division intended line 3. Such an operation is repeated until the workpiece 1 is processed along all the division intended lines 3 set to the workpiece 1. After the processing of the workpiece 1 is completed, the workpiece 1 is carried out from the holding table 40 by releasing the suction holding of the holding table 40.

[0085] Next, another example of a processing device used in the processing method of the workpiece in the present embodiment will be described. The processing device that processes the workpiece 1 can be, for example, a cutting device having a cutting tool in a circular ring shape.

[0086] Figure 10 is a perspective view schematically showing the cutting device 70. Figure 10 The cutting device 70 shown has the same constituent elements as the laser processing device 16. Figure 6 The cutting device 70 shown has the same constituent elements as the laser processing device 16.

[0087] The base 72, the X-axis guide rail 74, the X-axis moving table 76, the X-axis ball screw 78, the X-axis pulse motor 80, and the X-axis scale 82 of the cutting device 70 are equivalent to the same-named constituent elements of the laser processing device 16. Also, the same applies to the Y-axis guide rail 84, the table base 86, the side plate portion 86a, the bottom plate portion 86b, the top plate portion 86c, the space 86d, the Y-axis ball screw 88, the nut portion 88a, the Y-axis pulse motor 90, and the Y-axis scale 92.

[0088] Also, the same applies to the holding table (chuck table) 94, the holding member 94a, the pulley portion 94b, the suction passage 94c, the fine hole 94d, the fitting convex portion 94e, the belt 96, the rotation drive source 98, the pulley 98a, and the frame placement portion 116.

[0089] However, in the cutting device 70 shown in Figure 10 In the cutting device 70 shown, a plurality of fine holes 94d (see (A) of FIG. 10) are formed on the upper surface of the holding member 94a at substantially equal intervals along the outer periphery of the holding member 94a. Figure 12 In addition, a suction passage 94c (see (A) of FIG. 10) that communicates with each of the fine holes 94d is provided inside the holding member 94a. In the cutting device 70, the region in which the fine holes 94d and the suction passages 94c of the holding member 94a are formed is taken as a suction portion 94f, and the region other than the suction portion 94f is taken as a transparent portion 94g of the holding member 94a of the holding table 94. Figure 12 As shown in (A) of FIG. 10, the cutting device 70 has a holding table 94 that holds the workpiece 1.

[0090] Figure 10 ​As shown, a columnar or wall-shaped support structure 100 is provided at the rear of the upper surface of the base 72. A pair of Z-axis guide rails 102, which are approximately parallel to the Z-axis direction, are fixed on the front surface of the support structure 100. The spindle housing 104 of the cutting unit 118 is slidably mounted on the Z-axis guide rails 102. A nut portion (not shown) is provided on the rear surface side of the spindle housing 104, in which a Z-axis ball screw 106, which is approximately parallel to the Z-axis guide rails 102, is screwed.

[0091] A Z-axis pulse motor 108 is connected to one end of the Z-axis ball screw 106. If the Z-axis ball screw 106 is rotated by the Z-axis pulse motor 108, the spindle housing 104 moves in the Z-axis direction along the Z-axis guide rail 102. A Z-axis scale (not shown) is provided adjacent to the Z-axis guide rail 102 for detecting the position of the spindle housing 104 in the Z-axis direction.

[0092] The cutting unit 118 has a spindle 118b that serves as a rotation axis parallel to the Y-axis direction (see reference). Figure 11 The spindle 118b is supported in a rotatable state by the aforementioned spindle housing 104. The front end of the spindle 118b protrudes from the spindle housing 104. A cutting tool 118a, in which abrasive grains are fixed using a bonding material, is mounted on the front end of the spindle 118b. On the other hand, a rotary drive source such as an electric motor (not shown) is connected to the base end of the spindle 118b.

[0093] An upper imaging unit 120 for photographing the workpiece 1, etc., held by the holding table 94 from above is fixed on the spindle housing 104 of the cutting unit 118. The upper imaging unit 120 of the cutting device 70 corresponds to the upper imaging unit 52 of the laser processing device 16. In addition, the lower imaging unit 110, the lifting support mechanism 112, and the arm 114 of the cutting device 70 correspond to the lower imaging unit 54, the lifting support mechanism 56, and the arm 58 of the laser processing device 16.

[0094] In the cutting device 70, alignment is performed when machining the workpiece 1. Then, the workpiece 1 is cut. Figure 12 The cross-sectional view shown in (B) schematically illustrates the positional relationship between the workpiece 1 and the cutting unit 118 undergoing cutting. First, the X-axis pulse motor 80 and the Y-axis pulse motor 90 are activated to align the cutting tool 118a above the extension line of the predetermined dividing line 3, which is the workpiece. Then, the cutting tool 118a is positioned at a predetermined height such that its lower end reaches the piece 7.

[0095] Then, the cutting tool 118a is rotated while the holding stage 94 is moved in the X-axis direction. Thus, the workpiece 1 can be cut along the division intended line 3 as the machining target. Such an operation is repeated until the workpiece 1 is cut along all the division intended lines 3 provided in the workpiece 1. After the cutting of the workpiece 1 is completed, the workpiece 1 is carried out from the holding stage 94 by releasing the suction holding of the holding stage 94.

[0096] In the laser machining device 16 and the cutting device 70, alignment is performed before machining the workpiece 1. At this time, the front surface la side of the workpiece 1 is imaged through the sheet 7. In the past, in the case where the front surface la of the workpiece 1 is formed with unevenness, etc., the front surface la of the workpiece 1 cannot be clearly imaged, and thus alignment cannot be properly performed. This is because: a step difference emulating the unevenness of the workpiece 1 is generated on the surface of the sheet 7 held by the holding stage 40, 94. In addition, the same applies to the case where the surface of the sheet 7 not in contact with the workpiece 1 is a peeling surface.

[0097] In addition, when the sheet 7 not having the adhesive layer in the region corresponding to the device region of the workpiece 1 in which a plurality of devices 5 are formed is brought into close contact with the front surface la of the workpiece 1 having unevenness on the front surface la, a space can sometimes be formed between the sheet 7 and the workpiece 1. This is because: the recessed portion of the front surface la of the workpiece 1 is not in close contact with the sheet 7.

[0098] In this state, the workpiece 1 cannot be sufficiently supported by the sheet 7, and thus, particularly when the workpiece 1 is cut, it is likely that a chipping or a crack is formed on the device chip. In addition, the device chip formed by dividing the workpiece 1 can also be peeled off from the sheet 7 and scattered. In addition, machining water containing machining chips generated due to machining can also enter the space between the sheet 7 and the workpiece 1 and contaminate the front surface la of the workpiece 1.

[0099] Therefore, in the machining method and the thermocompression bonding method of the workpiece of the present embodiment, the sheet 7 and the flat plate 9 are stacked on the workpiece 1, the sheet 7 is flattened by the flat plate 9, and the sheet 7 is thermocompression bonded to the workpiece 1. Thus, the surface of the sheet 7 not in contact with the workpiece 1 becomes flat. In addition, even if the front surface la of the workpiece 1 is formed with unevenness, by thermocompression bonding the sheet 7 to the workpiece 1, the space between the sheet 7 and the workpiece 1 can be filled by the sheet 7. Therefore, the workpiece 1 is in close contact with the sheet 7.

[0100] Next, the processing method of the work and the heat press bonding method of the present embodiment will be described. In the processing method and the heat press bonding method, a laminating step of laminating the sheet 7 and the flat plate 9 on the work 1 is performed to form a laminate in which the sheet 7 is sandwiched by the work 1 and the flat plate 9. Also, after the laminating step, a heat press bonding step of heating the sheet 7 and applying an external force to the laminate to flatten the sheet 7 with the flat plate 9 while heat press bonding the sheet 7 on the work 1 is performed.

[0101] For example, the laminating step and the heat press bonding step will be described. In the laminating step, the work 1, the sheet 7, and the flat plate 9 are placed in this order on the heat press bonding device 2. Then, the laminate is formed on the heat press bonding device 2. However, in the laminating step, the laminate can also be formed outside the heat press bonding device 2. In this case, the laminate is placed on the heat press bonding device 2 when the heat press bonding step is performed. Figure 3

[0102] In the laminating step, when the laminate is formed, the sheet 7 is brought into contact with the face of the work 1 toward the holding stage of the processing device when processing is performed on the work 1 later. For example, in the case where the work 1 is processed from the back face 1b side later, in the laminating step, the sheet 7 and the flat plate 9 are laminated on the front face 1a of the work 1. At this time, the entire front face 1a of the work 1 is covered with the sheet 7.

[0103] In the heat press bonding step, first, the switching valve 12 of the heat press bonding device 2 is operated to cause the negative pressure generated by the suction source 10 to act on the work 1 through the suction path 8 and the porous member 6, and the work 1 is suction-adsorbed to the heat press bonding device 2. However, the work 1 can also not be suction-adsorbed.

[0104] Next, the heater 14 is operated to heat the laminate. At this time, heat is transferred to the sheet 7 through the work 1, and the sheet 7 is heated. Therefore, the output of the heater is set so that the temperature of the sheet 7 heated through the work 1 becomes a temperature equal to or higher than the softening temperature (softening point). However, when the temperature of the sheet 7 exceeds the melting point, the shape or properties of the sheet 7 cannot be controlled.

[0105] For example, in the case where the sheet 7 is a certain polyolefin-based sheet, the temperature of the upper surface of the heat press bonding device 2 is set to about 100°C so as to heat the sheet 7 to a temperature of 60°C or higher and 80°C or lower. Also, the laminate is heated by the heat press bonding device 2 for about 1 minute. At this time, the flat plate 9 is pressed from above with a prescribed force. Then, the sheet 7 is heat press-bonded on the front face 1a of the work 1.

[0106] ​When an external force is applied to the laminate to heat-press the sheet 7 onto the workpiece 1, even if there are irregularities on the front surface 1a of the workpiece 1, the sheet 7 will deform to follow the shape of the front surface 1a of the workpiece 1. Therefore, no space is created between the front surface 1a of the workpiece 1 and the sheet 7, and the sheet 7 is pressed tightly against the workpiece 1 with a strong force.

[0107] Furthermore, if the surface of sheet 7 that does not contact the workpiece 1 exhibits an uneven shape mimicking the front surface 1a of the workpiece 1, and this surface of sheet 7 becomes a pear-skin surface, then during the hot pressing step, this surface of sheet 7 is flattened. This is because, during the hot pressing step, sheet 7 is pressed against the flat surface of plate 9, and sheet 7 deforms following the shape of plate 9.

[0108] Then, the external force applied to the laminate is released, causing the heater 14 to stop. Furthermore, the switching valve 12 is activated to cut off the suction source 10 and the suction path 8, releasing the suction holding of the workpiece 1. Then, the workpiece 1, which has been heat-pressed onto the sheet 7, is picked up from the heat-pressing device 2, ending the heat-pressing step.

[0109] In addition, the lamination and hot pressing steps can utilize Figure 4 (A) and Figure 4 The hot-pressing device 2a shown in (B) is used for implementation. In this case, the workpiece 1, the sheet 7, and the annular frame 17 can be integrated to form a frame unit. When the workpiece 1 is in the frame unit state, subsequent operations become easier. In addition, when the workpiece 1 is divided to form a device chip, the device chip is supported on the frame 17 by means of the sheet 7.

[0110] In this case, during the lamination step, the workpiece 1 is placed on the lifting worktable 62 inside the housing of the hot pressing device 2a with its back side 1b facing downwards. Figure 4 In the example shown in (A), a metal layer 11 is formed on the back side 1b of the workpiece 1, and the metal layer 11 contacts the upper surface of the lifting worktable 62. Furthermore, the frame 17 is placed on a frame support 60 inside the housing. At this time, the workpiece 1 is housed within the opening of the frame 17.

[0111] Then, a sheet 7 is placed above the workpiece 1 and the frame 17, and a flat plate 9 is placed on the sheet 7. Additionally, in Figure 4 (A) and Figure 4 In the example shown in (B), sheet 7 has an adhesive layer 15 in an area that does not correspond to the device area of ​​workpiece 1. Furthermore, when sheet 7 is placed on frame 17, sheet 7 and frame 17 are bonded together by the adhesive layer 15.

[0112] Next, the switching valve 66 is activated to connect the pressurizing unit 68 to the pressure-boosting space of the thermocompression device 2a via the venting passage 64, causing the pressure in the pressure-boosting space to increase. Thus, as... Figure 4 As shown in (B), the lifting worktable 62 rises so that the front 1a side of the workpiece 1 comes into contact with the sheet 7. Thus, the workpiece 1 and the plate 9 hold the sheet 7, forming a stack of the workpiece 1, the sheet 7 and the plate 9.

[0113] In the hot pressing apparatus 2a, the hot pressing step is then performed. The lifting worktable 62 is further raised, and the workpiece 1 is pressed toward the sheet 7 by the lifting worktable 62. At the same time, the heater 14a is activated to heat the sheet 7 through the workpiece 1. When the temperature of the sheet 7 rises above its softening point, the sheet 7 and the workpiece 1 can be hot pressed together.

[0114] Then, when the switching valve 66 is activated to connect the pressurization space of the hot pressing device 2a with the external space of the hot pressing device 2a, the pressure in the pressurization space decreases, and the lifting worktable 62 descends. At this time, the workpiece 1 has been hot-pressed onto the sheet 7, thus the workpiece 1 becomes a floating state relative to the lifting worktable 62. That is, the workpiece 1, the sheet 7, and the frame 17 are integrated to form a frame unit.

[0115] In addition, the lamination and hot pressing steps can utilize Figure 5 (A) and Figure 5 The hot pressing device 2b shown in (B) is used for implementation. In this case, the workpiece 1, the sheet 7, and the annular frame 17 are also integrated to form a frame unit.

[0116] In this case, during the lamination and hot pressing steps, such as Figure 5 As shown in (A), the workpiece 1 and the frame 17 are placed on the heat-pressing device 2b with the back side 1b of the workpiece 1 facing downwards, and the sheet 7 and the plate 9 are arranged above the workpiece 1 and the frame 17. Then, the heater 14b is activated to heat the frame 17 and the workpiece 1.

[0117] And, as Figure 5 As shown in (B), the switching valve 12b is activated to connect the suction source 10b to the suction path 8b, thereby reducing the pressure on the space surrounded by the heat-pressing device 2b, the frame 17, and the sheet 7. In this case, the pressure difference between the inside and outside of the space presses the plate 9 downward, and the sheet 7 deforms as it enters the opening of the frame 17, adhering tightly to the front surface 1a of the workpiece 1. Furthermore, the sheet 7 is heated by the workpiece 1. When the temperature of the sheet 7 rises above its softening point, the sheet 7 is heat-pressed onto the workpiece 1.

[0118] Here, a case where the stacking step and the heat press-bonding step are performed simultaneously in the heat press-bonding device 2b is described, but the stacking step and the heat press-bonding step can also be implemented consecutively as in the heat press-bonding device 2a. In addition, in the heat press-bonding device 2a, the stacking step and the heat press-bonding step can also be performed simultaneously.

[0119] In the processed object processing method of the present embodiment, the processed object 1 is then processed by the processing device. In addition, before the processed object 1 is processed, a separation step of separating the flat plate 9 from the stack can further be implemented. In this case, the processed object 1 on which the heat press-bonding is performed on the sheet 7 is carried into the processing device. However, the processed object processing method of the present embodiment is not limited thereto. That is, the stack including the flat plate 9 can be carried into the processing device, and the processed object 1 can be processed in a state of being included in the stack.

[0120] Next, the holding step, the alignment step, and the processing step are described. Hereinafter, the case where the separation step is implemented to separate the flat plate 9 in advance, and the processed object 1 which is a part of the frame unit integrated with the sheet 7 and the frame 17 is laser-processed by the laser processing device 16 as shown in FIG. 10 is described. Figure 6

[0121] In the laser processing device 16, first, the holding step is implemented, and the processed object 1 is held by the holding stage 40 with the sheet 7 interposed therebetween. As described above, the holding member 40a of the holding stage 40 has the transparency 40g including a transparent member. In the holding step, as shown in FIG. 11, the processed object 1 is placed on the holding member 40a of the holding stage 40 with the sheet 7 interposed therebetween, and the annular frame 17 is placed on the frame placement portion 46. Figure 7

[0122] Next, as shown in FIG. 12, the processed object 1 is subjected to negative pressure via the suction path 40c and the suction groove 40d, and the processed object 1 is suction-held to the holding stage 40. Thus, a state where the back surface 1b side of the processed object 1 is exposed upward and the back surface 1b side of the processed object 1 can be irradiated with a laser beam from the laser processing unit 50 is achieved. Figure 8

[0123] After the holding step is implemented, the alignment step is implemented. In the alignment step, the processed object 1 is photographed with the sheet 7 interposed between the transparency 40g of the holding member 40a of the holding stage 40 and the processed object 1, and the alignment of the laser processing unit 50 (processing unit) is implemented. Figure 9 (A) of FIG. 13 is a cross-sectional view schematically showing the alignment step.

[0124] ​​​In the alignment step, the holding stage 40 is moved to position the lower photographing unit 54 below the workpiece 1 held by the holding stage 40. In particular, the lower photographing unit 54 is positioned below the transparent portion 40g. Also, the lower photographing unit 54 is activated to photograph the front surface la side of the workpiece 1 through the transparent portion 40g of the holding stage 40.

[0125] Here, in the workpiece processing method of the present embodiment, the heat press bonding step is implemented, and thus the space between the sheet 7 and the workpiece 1 is filled. Also, the sheet 7 is flattened by the flat plate 9. Thus, when the workpiece 1 is photographed through the sheet 7, a clear photographed image is obtained. Therefore, from the photographed image, the position and direction of the division intended line 3 of the workpiece 1, the pitch of the division intended line 3, and the like can be detected with high precision, and thus precise alignment can be implemented.

[0126] Next, the processing step is implemented, and the workpiece 1 is processed by the laser processing unit 50 (processing unit). Figure 9 FIG. 9 is a cross-sectional view schematically showing the processing step. In the processing step, first, the holding stage 40 is rotated by activating the rotary drive source 44, and the division intended line 3 is aligned with the X-axis direction (processing feed direction). Also, the laser processing unit 50 is moved above the extension line of the division intended line 3 that is the object of processing to be implemented first.

[0127] Also, the optical system of the laser processing unit 50 is adjusted to position the height position of the focal point 50b of the laser processing unit 50 at a prescribed height. Also, the workpiece 1 is processed fed while the laser beam 50a having a wavelength that is transmissive to the workpiece 1 is irradiated from the laser processing unit 50 to the back surface lb side of the workpiece 1. Thus, a modified layer 3a is formed inside the workpiece 1 along the division intended line 3.

[0128] After the laser processing along the division intended line 3 is completed, the workpiece 1 is index fed along the Y-axis direction, and the workpiece 1 is laser processed along the other division intended lines 3 in turn. Also, after the workpiece 1 is laser processed along all of the division intended lines 3 in the X-axis direction, the workpiece 1 is rotated to laser process the workpiece 1 along the division intended lines 3 in another direction. In this way, when the modified layer 3a is formed inside the workpiece 1 along all of the division intended lines 3 of the workpiece 1, the processing step is completed.

[0129] Then, the workpiece 1 is carried out from the laser processing apparatus 16, and the workpiece 1 is cleaned. When the sheet 7 is expanded to the radial outside, the cracks extend upward and downward from the modified layer 3a, and the workpiece 1 is divided to form individual device chips. Further, the device chips are picked up from the sheet 7 and mounted on a prescribed mounting object to be used. In addition, in the processing step, the workpiece 1 can be subjected to ablation processing by irradiating the workpiece 1 with a laser beam of a wavelength that the workpiece 1 can absorb.

[0130] In addition, the holding step, the alignment step, and the processing step can be implemented in the cutting apparatus 70 shown in FIG. 10. Next, a case in which the workpiece 1 included in the frame unit formed by thermocompression bonding the sheet 7 on the front surface la of the workpiece 1 and adhering the sheet 7 to the frame 17 via the adhesive layer 15 is subjected to cutting in the cutting apparatus 70 will be described. Here, a case in which the metal layer 11 is formed on the back surface lb of the workpiece 1 will be described as an example. Figure 10

[0131] As for the holding step and the alignment step, the same operations as in the case of implementation by the laser processing apparatus 16 described above are performed, and thus a part of the description is omitted. It is desirable to refer to the description of the holding step and the alignment step implemented by the laser processing apparatus 16 described above as needed.

[0132] In the holding step, as shown in FIG. 11, the workpiece 1 is placed on the holding member 94a of the holding table 94 with the sheet 7 interposed therebetween, and the annular frame 17 is placed on the frame placement portion 116. Next, as shown in (B) of FIG. 11, the workpiece 1 is subjected to negative pressure via the suction passage 94c and the fine hole 94d of the holding table 94, and the workpiece 1 is suction-held to the holding table 94. Thus, the back surface lb side of the workpiece 1 faces upward, and the metal layer 11 formed on the back surface lb is exposed upward. Figure 11 Figure 12 In addition, particularly in the case where the metal layer 11 is formed on the back surface lb side, it is difficult to take an image of the front surface la side of the workpiece 1 using the upper imaging unit 120 provided on the upper side of the holding table 94. Therefore, in the alignment step implemented after the holding step, the front surface la side of the workpiece 1 is imaged using the lower imaging unit 110. That is, in the alignment step, the workpiece 1 is imaged through the transparent portion 94g of the holding member 94a of the holding table 94 and the sheet 7, and the alignment of the cutting unit 118 (processing unit) is implemented.

[0133] Next, the processing step is implemented, and the workpiece 1 is processed by the cutting unit 118 (processing unit).

[0134] Next, the processing step is implemented, and the workpiece 1 is processed by the cutting unit 118 (processing unit). Figure 12 ​​(B) is a cross-sectional view schematically showing a machining step. In the machining step, first, the rotation drive source 44 is activated to rotate the holding table 40, and the division predetermined line 3 is aligned with the X-axis direction (machining feed direction). In addition, the cutting unit 118 is moved above the extension line of the division predetermined line 3 that is the object of machining performed first.

[0135] Also, the cutting unit 118 is lowered with the cutting tool 118a rotated as a rotation axis until the lower end of the cutting tool 118a reaches a prescribed height of the sheet 7. Also, the rotation of the cutting tool 118a is continued while the workpiece 1 is machined fed. Thus, the workpiece 1 is cut along the division predetermined line 3 and divided. When the workpiece 1 is divided along all the division predetermined lines 3, each device chip is formed.

[0136] Here, in the machining method of the workpiece of the present embodiment, no space is left between the workpiece 1 and the sheet 7, and the workpiece 1 is properly supported by the sheet 7, so even if the workpiece 1 is cut, generation of chipping or cracks can be suppressed.

[0137] In the machining method of the workpiece of the present embodiment, the workpiece 1 is thermocompression-bonded to the sheet 7, so the sheet 7 and the workpiece 1 are firmly in close contact. Thus, the workpiece 1 or the device chip is firmly supported by the sheet 7 in the machining step, a cleaning step performed after the machining step, and the like. In this case, the workpiece 1 or the device chip does not peel off from the sheet 7 and scatter. In addition, no space is left between the workpiece 1 and the sheet 7, so a contamination source does not enter the space.

[0138] In addition, in the above-described embodiment, a case where the sheet 7 is heated by the heaters 14, 14a, 14b of the thermocompression-bonding apparatuses 2, 2a, 2b used in the thermocompression-bonding step is described, but one embodiment of the present application is not limited to this. For example, the thermocompression-bonding apparatuses 2, 2a, 2b can have an infrared lamp capable of irradiating infrared rays to the sheet 7, or a hot air blower capable of supplying hot air to the sheet 7. That is, in the thermocompression-bonding step, the sheet 7 can be heated by the infrared lamp or the hot air blower.

[0139] In addition, in the above-described embodiment, a case where the concave-convex shape is formed on the front surface la of the workpiece 1 is mainly described, but one embodiment of the present application is not limited to this. That is, the concave-convex shape can not be formed on the front surface la of the workpiece 1. In addition, a case where the workpiece 1 is machined from the back surface lb side in the machining step is described, but the front surface la side of the workpiece 1 can be exposed to the upper surface and the workpiece 1 can be machined from the front surface la side.

[0140] Further, although the case where the workpiece 1 is subjected to laser processing by the laser processing unit and the case where the workpiece 1 is subjected to cutting by the cutting unit are exemplified as the processing step, one embodiment of the present application is not limited to these. For example, in the processing step, the back surface Ib side of the workpiece 1 can be subjected to grinding by a grinding unit, or the back surface Ib side of the workpiece 1 can be subjected to polishing by a polishing unit. In these cases, according to one embodiment of the present application, the workpiece 1 is firmly attached to the sheet 7, and thus peeling of the workpiece 1 from the sheet 7 can be suppressed, and high-quality processing can be performed.

[0141] In addition, the configuration, method, and the like of the above-described embodiments can be appropriately changed and implemented as long as the scope of the object of the present application is not deviated.

Claims

1. A processing method of an object to be processed, characterized by comprising: a lamination step of laminating a sheet and a flat plate on a front surface of the object to be processed to form a laminate in which the sheet is sandwiched by the object to be processed and the flat plate; a heat pressure bonding step of heating the sheet and applying an external force to the laminate to flatten the sheet using the flat plate while heat pressure bonding the sheet to the object to be processed; a holding step of holding the object to be processed using a holding stage having a transparent portion including a transparent member across the sheet after the heat pressure bonding step is performed; an alignment step of performing alignment by taking a photograph of the object to be processed across the transparent portion and the flattened sheet after the holding step is performed; and a processing step of processing the object to be processed using a processing unit after the alignment step is performed, the object to be processed has a device region in which a plurality of devices are formed on the front surface, and the sheet has no adhesiveness at least in a region corresponding to the device region of the object to be processed in which the plurality of devices are formed.

2. The processing method of the object to be processed according to claim 1, characterized in that: the object to be processed has a concave-convex on the front surface, the sheet has a thickness greater than a height difference of the concave-convex, in the lamination step, the sheet is laminated on the front surface of the object to be processed, in the heat pressure bonding step, the sheet is heat pressure bonded to the front surface of the object to be processed, in the holding step, the front surface side of the object to be processed is held across the sheet using the holding stage, in the processing step, the object to be processed is processed from a back surface side of the object to be processed using the processing unit. ​ ​

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