Method for manufacturing a device chip

Abstract

To provide a method for manufacturing a device chip that allows appropriate division of a workpiece.SOLUTION: A method for manufacturing a device chip is to manufacture device chips by dividing a workpiece including, on its front side, a laminate that forms devices provided in a plurality of areas partitioned by a plurality of intersecting division scheduled lines, and the method includes: a support member fixing step of fixing a support member on the front side of the workpiece; a rear side grinding step of grinding a rear side of the workpiece; a support member removal step of removing the support member from the front side of the workpiece; a processing groove forming step of irradiating the laminate with a laser beam with a wavelength having absorbency from the front side of the workpiece along the division scheduled line to form processing grooves for dividing the laminate along the division scheduled lines; a resin layer forming step of forming a resin layer on the front side of the workpiece; and a division step of dividing the workpiece and the resin layer along the division scheduled line.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a device chip that divides a workpiece to manufacture a device chip.

Background Art

[0002] In the manufacturing process of a device chip, a wafer in which devices are formed in a plurality of regions partitioned by a plurality of division planned lines (streets) intersecting each other is used. By dividing this wafer along the division planned lines, a plurality of device chips each having a device can be obtained. The device chips are incorporated into various electronic devices such as mobile phones and personal computers.

[0003] For wafer dicing, a dicing device is used. The dicing device includes a chuck table for holding the workpiece and a cutting unit for cutting the workpiece. The cutting unit incorporates a spindle, and an annular cutting blade is attached to the tip of the spindle. By holding the wafer on the chuck table and cutting into the wafer while rotating the cutting blade, the wafer is cut along the division planned lines and divided into a plurality of device chips.

[0004] In recent years, the development of a process for dividing a wafer by laser processing has also been advanced. For example, while condensing a laser beam having a wavelength that is transmissive to the wafer inside the wafer, by scanning the laser beam along the division planned line, a modified layer is formed along the division planned line inside the wafer. The region where the modified layer of the wafer is formed becomes more brittle than other regions. Therefore, when an external force is applied to the wafer in which the modified layer is formed, the modified layer functions as a division starting point and the wafer is divided along the division planned line.

[0005] The device chips obtained by dividing the wafer are mounted by various mounting methods such as wire bonding mounting, flip chip mounting, etc. For example, the device chips are bonded to a mounting substrate or other device chips via a film-like resin layer (adhesive film) that seals the device (see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-92188 A Summary of the Invention [Problem to be solved by the invention]

[0007] A laminate is formed on the front surface of a workpiece (such as a wafer) used to manufacture device chips, in which various thin films such as a conductive film that functions as an electrode and an insulating film (e.g., a low-k film) that functions as an interlayer insulating film are laminated. This laminate constitutes devices and TEGs (Test Element Groups) for testing devices. A resin layer that seals the devices is then formed on the workpiece, and the workpiece is then divided to obtain device chips with a bonding material made of resin.

[0008] The laminate is also formed on the dividing line on the outside of the device. When dividing the workpiece into a plurality of device chips, the laminate remaining on the dividing line may hinder proper division of the workpiece. For example, when cutting the workpiece with a cutting blade, a thin film contained in the laminate on the dividing line may be caught in the rotation of the cutting blade and peeled off, which may cause damage to the device or peeling of the resin layer. In addition, when dividing the workpiece by applying an external force to the workpiece on which the modified layer is formed, the functional layer present on the dividing line may not be properly divided together with the workpiece, resulting in peeling of the laminate.

[0009] The present invention has been made in view of such problems, and an object thereof is to provide a method for manufacturing a device chip that enables appropriate division of a workpiece.

Means for Solving the Problems

[0010] According to one aspect of the present invention, there is provided a method for manufacturing a device chip, which divides a workpiece having a laminate constituting a device provided in a plurality of regions partitioned by a plurality of intersecting planned division lines on the surface side to manufacture a device chip, including a support member fixing step of fixing a support member to the surface side of the workpiece, a back surface grinding step of grinding the back surface side of the workpiece after the support member fixing step, a support member removing step of removing the support member from the surface side of the workpiece after the back surface grinding step, a processing groove forming step of irradiating a laser beam having an absorbent wavelength with respect to the laminate from the surface side of the workpiece along the planned division line to form a processing groove for dividing the laminate along the planned division line, a resin layer forming step of forming a resin layer on the surface side of the workpiece after the processing groove forming step, and a dividing step of dividing the workpiece and the resin layer along the planned division line after the resin layer forming step.

[0011] Preferably, the method for manufacturing the device chip further includes a back surface pattern forming step of forming a pattern on the back surface side of the workpiece after the back surface grinding step. Also preferably, the method for manufacturing the device chip further includes a protective film forming step of forming a protective film on the surface side of the workpiece before the processing groove forming step. Also preferably, the method for manufacturing the device chip further includes a plasma etching step of supplying an etching gas in a plasma state from the surface side of the workpiece after the processing groove forming step to remove processing strain or foreign matter remaining in the workpiece or the laminate.

[0012] Also, preferably, in the dividing step, the workpiece and the resin layer are cut along the planned dividing line with a cutting blade. Further preferably, the method for manufacturing the device chip further includes an expand sheet attaching step of attaching an expand sheet having extensibility to the workpiece before the dividing step, and the dividing step includes a modified layer forming step of irradiating a laser beam having a wavelength that is permeable to the workpiece with the condensing point of the laser beam positioned inside the workpiece to form a modified layer along the planned dividing line on the workpiece, and an expanding step of expanding the expand sheet after the modified layer forming step.

Advantages of the Invention

[0013] In the method for manufacturing a device chip according to one aspect of the present invention, before dividing the workpiece, a processing groove for dividing the laminate is formed along the planned dividing line. Thereby, peeling of the laminate during division of the workpiece is avoided, and damage to the device and peeling of the resin layer are prevented.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments according to an aspect of the present invention will be described with reference to the accompanying drawings. First, a configuration example of a workpiece that can be used in the method for manufacturing a device chip according to the present embodiment will be described. FIG. 1(A) is a perspective view showing a workpiece 11.

[0016] For example, the workpiece 11 is a disk-shaped wafer (substrate) made of a semiconductor such as silicon, and includes surfaces (first surface) 11a and a back surface (second surface) 11b that are substantially parallel to each other. However, there are no restrictions on the material, shape, structure, size, etc. of the workpiece 11. For example, the workpiece 11 may be a substrate made of a semiconductor other than silicon (GaAs, SiC, InP, GaN, etc.), sapphire, glass, ceramics, resin, metal, or the like.

[0017] On the surface 11a side of the workpiece 11, a laminate 13 including a plurality of laminated thin films is provided. The laminate 13 includes various thin films such as a conductive film that functions as an electrode, wiring, a terminal, etc., and an insulating film that functions as an interlayer insulating film (for example, a low dielectric constant insulating film (Low-k film)), and is formed over the entire surface 11a side of the workpiece 11.

[0018] The workpiece 11 is partitioned into a plurality of rectangular regions by a plurality of division planned lines (streets) 15 arranged in a grid pattern so as to intersect each other. And in each of the plurality of regions partitioned by the division planned line 15, devices 17 such as IC (Integrated Circuit), LSI (Large Scale Integration), LED (Light Emitting Diode), and MEMS (Micro Electro Mechanical Systems) devices are formed. However, there are no restrictions on the type, quantity, shape, structure, size, arrangement, etc. of the devices 17.

[0019] The device 17 is provided with a plurality of connection electrodes (bumps) 19 protruding from the surface of the device 17. For example, the connection electrode 19 is a spherical electrode made of a metal material such as solder, and is connected to other electrodes etc. included in the device 17.

[0020] FIG. 1(B) is a cross-sectional view showing a part of the workpiece 11. A plurality of regions surrounded by the division planned line 15 in the laminate 13 each constitute a device 17. For example, a semiconductor element is constituted by the surface 11a side of the workpiece 11 and the thin films included in the laminate 13. Also, a part of the thin films (such as a Low-k film) included in the laminate 13 is also formed on the division planned line 15. Note that the portion of the laminate 13 formed on the division planned line 15 may constitute a TEG etc. used for inspection of the device 17.

[0021] Inside each of a plurality of regions partitioned by a planned division line 15 of the workpiece 11, a plurality of electrodes (embedded electrodes, through electrodes) 21 are embedded. The electrodes 21 are formed in a columnar shape along the thickness direction of the workpiece 11 and are connected to the device 17. Note that there is no limitation on the material of the electrodes 21, and for example, metals such as copper, tungsten, and aluminum are used.

[0022] The electrodes 21 are each formed from the device 17 toward the back surface 11b side of the workpiece 11, and the length (height) of the electrodes 21 is less than the thickness of the workpiece 11. Therefore, the electrodes 21 are not exposed on the back surface 11b side of the workpiece 11 and are in a state of being buried inside the workpiece 11. Also, an insulating layer (not shown) for insulating the workpiece 11 and the electrodes 21 is provided between the workpiece 11 and the electrodes 21.

[0023] Next, a specific example of a method for manufacturing a device chip by dividing the workpiece 11 to manufacture a device chip will be described. In the present embodiment, a processing groove for dividing the laminate 13 is formed along the planned division line 15, a resin layer is formed on the surface 11a side of the workpiece 11, and then the workpiece 11 and the resin layer are divided along the planned division line 15 to manufacture a device chip.

[0024] First, a support member is fixed to the surface 11a side of the workpiece 11 (support member fixing step). FIG. 2(A) is a perspective view showing the workpiece 11 in the support member fixing step.

[0025] The support member 23 is a member that supports the workpiece 11 in a back surface grinding step (see FIG. 3(A)) described later. For example, as the support member 23, a disk-shaped substrate (support substrate) made of glass, silicon, resin, ceramics, or the like is used. The support member 23 is joined to the surface 11a side (laminate 13 side) of the workpiece 11 via an adhesive layer 25. As the adhesive layer 25, an epoxy-based, acrylic-based, or rubber-based adhesive, an ultraviolet curable resin, or the like can be used.

[0026] FIG. 2(B) is a cross-sectional view showing a part of the workpiece 11 after the support member fixing step. When the support member 23 is fixed to the workpiece 11, the workpiece 11 is supported by the support member 23. Note that, as the support member 23, a flexible sheet-like member can also be used. For example, a support tape having the same material and structure as the tape 31 (see FIG. 5) described later may be adhered to the workpiece 11 as the support member 23.

[0027] Next, the back surface 11b side of the workpiece 11 is ground (back surface grinding step). FIG. 3(A) is a perspective view showing the workpiece 11 in the back surface grinding step. In the back surface grinding step, the workpiece 11 is ground by the grinding device 2.

[0028] The grinding device 2 includes a chuck table (holding table) 4 that holds the workpiece 11. The upper surface of the chuck table 4 is a circular flat surface that is generally parallel to the horizontal direction, and constitutes a holding surface 4a for holding the workpiece 11. The holding surface 4a is connected to a suction source (not shown) such as an ejector via a flow path (not shown), a valve (not shown), etc. formed inside the chuck table 4.

[0029] A moving mechanism (not shown) for moving the chuck table 4 along the horizontal direction is connected to the chuck table 4. Further, a rotational drive source such as a motor for rotating the chuck table 4 around a rotation axis that is generally parallel to the vertical direction (height direction, up and down direction) is connected to the chuck table 4.

[0030] Above the chuck table 4, a grinding unit 6 is provided. The grinding unit 6 includes a columnar spindle 8 arranged along the vertical direction. A disk-shaped mount 10 made of metal or the like is fixed to the tip end portion (lower end portion) of the spindle 8. Further, a rotational drive source (not shown) such as a motor for rotating the spindle 8 is connected to the base end portion (upper end portion) of the spindle 8.

[0031] An annular grinding wheel 12 is mounted on the mount 10. The grinding wheel 12 is a machining tool for grinding the workpiece 11, and is fixed to the lower surface side of the mount 10 by a fixture such as a bolt. The grinding wheel 12 rotates around a rotation axis substantially parallel to the vertical direction by the power transmitted from a rotation drive source through the spindle 8 and the mount 10.

[0032] The grinding wheel 12 includes an annular base 14. The base 14 is made of a metal such as aluminum or stainless steel, and is formed to have substantially the same diameter as the mount 10. A plurality of grinding wheels 16 are fixed to the lower surface side of the base 14. For example, the plurality of grinding wheels 16 are formed in a rectangular parallelepiped shape and are arranged annularly at substantially equal intervals along the circumferential direction of the base 14.

[0033] The grinding wheel 16 includes abrasive grains made of diamond, cBN (cubic Boron Nitride), etc., and a binder (bonding material) for fixing the abrasive grains. As the binder, a metal bond, a resin bond, a vitrified bond, etc. are used. However, there are no restrictions on the material, shape, structure, size, etc. of the grinding wheel 16. Also, the number of the grinding wheels 16 can be arbitrarily set.

[0034] In the back grinding step, first, the workpiece 11 is held by the chuck table 4. Specifically, the workpiece 11 is placed on the chuck table 4 such that the surface 11a side (the laminate 13 side, the support member 23 side) faces the holding surface 4a and the back surface 11b side is exposed upward. When the suction force (negative pressure) of the suction source is applied to the holding surface 4a in this state, the workpiece 11 is suction-held by the chuck table 4 via the support member 23.

[0035] Next, the chuck table 4 is moved to place the workpiece 11 below the grinding unit 6. At this time, the positional relationship between the chuck table 4 and the grinding unit 6 is adjusted so that the rotation axis of the chuck table 4 (the center of the workpiece 11) and the orbit (rotation path) of the grinding wheel 16 overlap.

[0036] While rotating the chuck table 4 and the grinding wheel 12 respectively, the grinding wheel 12 is lowered, and the plurality of rotating grinding wheels 16 are brought into contact with the back surface 11b side of the workpiece 11. As a result, the back surface 11b side of the workpiece 11 is ground, and the workpiece 11 is thinned.

[0037] FIG. 3(B) is a cross-sectional view showing a part of the workpiece 11 after the back surface grinding step. The grinding of the workpiece 11 is continued until the electrode 21 embedded in the workpiece 11 is exposed on the back surface 11b of the workpiece 11. As a result, a through electrode penetrating the workpiece 11 in the thickness direction is formed.

[0038] Note that, by performing other processes after grinding the workpiece 11, the electrode 21 may be exposed on the back surface 11b of the workpiece 11. For example, after grinding the workpiece 11 until immediately before the electrode 21 is exposed on the back surface 11b of the workpiece 11 in the back surface grinding step, the electrode 21 may be exposed on the back surface 11b of the workpiece 11 by performing processes such as dry etching, wet etching, and polishing on the back surface 11b side of the workpiece 11. In this case, it is possible to prevent the grinding wheel 16 from contacting the electrode 21 and the metal contained in the electrode 21 from scattering.

[0039] Next, a pattern is formed on the back surface 11b side of the workpiece 11 (back surface pattern forming step). FIG. 4 is a cross-sectional view showing a part of the workpiece 11 on which the pattern layer 27 is formed.

[0040] The pattern layer 27 is a functional layer having a predetermined function similar to the laminate 13, and includes a pattern of an insulating film, a conductive film, or a laminate thereof. For example, the pattern layer 27 includes a connection electrode connected to the electrode 21, an insulating layer insulating the connection electrodes from each other, a wiring connected to the connection electrode, a terminal, an element, and the like.

[0041] The pattern layer 27 is appropriately designed according to the structure and function of the device chip obtained by dividing the workpiece 11, the structure and function of the mounting destination of the device chip, and the like. Further, when the formation of the pattern layer 27 is not necessary, the back surface pattern forming step can be omitted.

[0042] Next, the support member 23 is removed from the surface 11a side of the workpiece 11 (support member removal step). FIG. 5 is a perspective view showing the workpiece 11 in the support member removal step.

[0043] In the support member removal step, first, the workpiece 11 is supported by an annular frame 29. The frame 29 is an annular member made of a metal such as SUS (stainless steel), and a circular opening 29a penetrating the frame 29 in the thickness direction is provided at the central portion of the frame 29. Note that the diameter of the opening 29a is larger than the diameter of the workpiece 11.

[0044] A circular tape 31 having a diameter larger than that of the workpiece 11 is adhered to the back surface 11b side of the workpiece 11. For example, the tape 31 includes a film-shaped base material formed in a circular shape and an adhesive layer (paste layer) provided on the base material. The base material is made of a resin such as polyolefin, polyvinyl chloride, or polyethylene terephthalate. The adhesive layer is made of an epoxy-based, acrylic-based, or rubber-based adhesive or the like. Note that the adhesive layer may be an ultraviolet curable resin that is cured by irradiation with ultraviolet rays.

[0045] With the workpiece 11 disposed inside the opening 29a of the frame 29, the central portion of the tape 31 is adhered to the back surface 11b side of the workpiece 11, and the outer peripheral portion of the tape 31 is adhered to the frame 29. Thereby, the workpiece 11 is supported by the frame 29 via the tape 31.

[0046] Next, with the workpiece 11 held, the support member 23 is moved in a direction away from the workpiece 11, thereby peeling the support member 23 from the workpiece 11. Thereby, the support member 23 is removed from the workpiece 11.

[0047] When peeling the support member 23, a predetermined treatment may be performed on the adhesive layer 25 in advance to reduce the adhesive force of the adhesive layer 25. This makes it easier to separate the support member 23 from the workpiece 11. For example, when the adhesive layer 25 is an ultraviolet curable resin, the support member 23 is removed after irradiating the adhesive layer 25 with ultraviolet light. Further, when the adhesive layer 25 remains on the workpiece 11 after removing the support member 23, the workpiece 11 may be subjected to a cleaning treatment.

[0048] Next, a protective film is formed on the surface 11a side (laminated body 13 side) of the workpiece 11 (protective film forming step). FIG. 6(A) is a cross-sectional view showing the workpiece 11 in the protective film forming step. For example, in the protective film forming step, a protective film is formed on the workpiece 11 by a spin coater 20.

[0049] The spin coater 20 includes a spinner table (chuck table) 22 that holds the workpiece 11. The upper surface of the spinner table 22 constitutes a flat holding surface 22a for holding the workpiece 11. The holding surface 22a is connected to a suction source (not shown) such as an ejector via a flow path (not shown), a valve, etc. formed inside the spinner table 22.

[0050] A rotation drive source (not shown) such as a motor for rotating the spinner table 22 around a rotation axis substantially parallel to the vertical direction is connected to the spinner table 22. Further, a plurality of clamps 24 for gripping and fixing the frame 29 are provided around the spinner table 22.

[0051] Above the spinner table 22, a protective film material supply unit 26 for supplying a protective film material 28, which is a raw material of the protective film, is provided. For example, the protective film material supply unit 26 includes a nozzle for dropping the protective film material 28 toward the workpiece 11 held by the spinner table 22.

[0052] In the protective film forming step, first, the workpiece 11 is held by the spinner table 22. Specifically, the workpiece 11 is placed on the spinner table 22 such that the surface 11a side (laminate 13 side) faces upward and the back surface 11b side (tape 31 side) faces the holding surface 22a. Also, the frame 29 is fixed by a plurality of clamps 24. When the suction force (negative pressure) of the suction source is applied to the holding surface 22a in this state, the workpiece 11 is suction-held by the spinner table 22 via the tape 31.

[0053] Next, while rotating the spinner table 22, the protective film material 28 is supplied from the nozzle of the protective film material supply unit 26 toward the workpiece 11. Thereby, the surface 11a side of the workpiece 11 is covered with the protective film material 28. Then, the protective film material 28 applied to the workpiece 11 is dried and cured, whereby a protective film is formed on the surface 11a side of the workpiece 11.

[0054] FIG. 6(B) is a cross-sectional view showing a part of the workpiece 11 after the protective film forming step. A protective film 33 is formed on the surface 11a side of the workpiece 11 so as to cover the laminate 13 and the connection electrode 19.

[0055] Note that there is no limitation on the material of the protective film 33. For example, as the protective film material 28 (see FIG. 6(A)), a water-soluble resin such as PVA (polyvinyl alcohol), PEG (polyethylene glycol), PEO (polyethylene oxide), or PVP (polyvinyl pyrrolidone) is used. In this case, a protective film 33 made of a water-soluble resin is formed. Also, a resin tape may be adhered to the surface 11a side of the workpiece 11 as the protective film 33.

[0056] Next, a laser beam having an absorbable wavelength is irradiated from the surface 11a side of the workpiece 11 along the division planned line 15 to the laminate 13, and a processing groove for dividing the laminate 13 is formed along the division planned line 15 (processing groove forming step). FIG. 7(A) is a cross-sectional view showing the workpiece 11 in the processing groove forming step.

[0057] In the machining groove forming step, the workpiece 11 is subjected to laser machining by the laser machining apparatus 30. The X-axis direction (machining feed direction, first horizontal direction) and the Y-axis direction (indexing feed direction, second horizontal direction) are perpendicular to each other. The Z-axis direction (vertical direction, up-and-down direction, height direction) is perpendicular to the X-axis direction and the Y-axis direction.

[0058] The laser machining apparatus 30 includes a chuck table (holding table) 32 for holding the workpiece 11. The upper surface of the chuck table 32 is a circular flat surface generally parallel to the horizontal direction (XY plane direction), and constitutes a holding surface 32a for holding the workpiece 11. The holding surface 32a is connected to a suction source (not shown) such as an ejector via a flow path (not shown), a valve (not shown), etc. formed inside the chuck table 32.

[0059] A ball screw type movement mechanism (not shown) for moving the chuck table 32 along the X-axis direction and the Y-axis direction is connected to the chuck table 32. A rotation drive source (not shown) such as a motor for rotating the chuck table 32 around a rotation axis substantially perpendicular to the holding surface 32a is connected to the chuck table 32. Further, a plurality of clamps 34 for gripping and fixing the frame 29 are provided around the chuck table 32.

[0060] The laser machining apparatus 30 also includes a laser irradiation unit 36. The laser irradiation unit 36 includes a laser oscillator (not shown) such as a YAG laser, a YVO 4 laser, a YLF laser, etc., and a laser machining head 38 disposed above the chuck table 32. The laser machining head 38 incorporates an optical system for guiding the pulsed laser beam emitted from the laser oscillator to the workpiece 11, and the optical system includes optical elements such as a condenser lens for condensing the laser beam. The laminate 13 is machined by the laser beam 40 irradiated from the laser irradiation unit 36.

[0061] In the processing groove formation step, first, the workpiece 11 is held by the chuck table 32. Specifically, the workpiece 11 is placed on the chuck table 32 such that the surface 11a side (laminated body 13 side) faces upward and the back surface 11b side (tape 31 side) faces the holding surface 32a. Also, the frame 29 is fixed by a plurality of clamps 34. In this state, when the suction force (negative pressure) of the suction source is applied to the holding surface 32a, the workpiece 11 is suction-held by the chuck table 32 via the tape 31.

[0062] Next, the chuck table 32 is rotated to align the length direction of the predetermined division line 15 with the machining feed direction (X-axis direction). Also, the position of the chuck table 32 in the indexing feed direction (Y-axis direction) is adjusted so that the position in the Y-axis direction of the region irradiated with the laser beam 40 coincides with the region inside both ends in the width direction of the division line 15 (for example, the center in the width direction of the division line 15). Further, the position of the laser processing head 38 and the arrangement of the optical system are adjusted so that the focus point of the laser beam 40 is positioned at the same height position (position in the Z-axis direction) as the surface or inside of the laminated body 13.

[0063] Then, while irradiating the laser beam 40 from the laser processing head 38, the chuck table 32 is moved along the machining feed direction (X-axis direction). As a result, the chuck table 32 and the laser beam 40 relatively move along the machining feed direction (X-axis direction) at a predetermined speed (machining feed speed). As a result, the laser beam 40 is irradiated along the division line 15 from the surface 11a side (laminated body 13 side) of the workpiece 11.

[0064] Note that the irradiation conditions of the laser beam 40 are set such that the laminate 13 is subjected to ablation processing. Specifically, the wavelength of the laser beam 40 is set such that at least a part of the laser beam 40 is absorbed by the laminate 13. That is, the laser beam 40 is a laser beam having a wavelength that is absorbable by the laminate 13. Also, the other irradiation conditions of the laser beam 40 are appropriately set so that ablation processing is appropriately performed on the laminate 13. For example, the irradiation conditions of the laser beam 40 can be set as follows. Wavelength: 355 nm Average output: 2 W Repetition frequency: 200 kHz Processing feed rate: 400 mm / s

[0065] When the laminate 13 is irradiated with the laser beam 40 along the division planned line 15, the area of the laminate 13 irradiated with the laser beam 40 is removed by ablation processing. As a result, a linear processing groove 35 is formed along the division planned line 15 on the surface 11a side of the workpiece 11.

[0066] The processing groove 35 is formed so that its depth is equal to or greater than the thickness of the laminate 13. Therefore, when the processing groove 35 is formed, the laminate 13 is divided along the division planned line 15, and the surface 11a side of the workpiece 11 inside the processing groove 35 is exposed. Note that depending on the irradiation conditions of the laser beam 40, a part of the surface 11a side of the workpiece 11 is also slightly removed, and a processing groove 35 having a depth exceeding the thickness of the laminate 13 is formed.

[0067] In the processing groove forming step, a processing groove 35 having a desired depth may be formed by irradiating the same region on each division planned line 15 with the laser beam 40 a plurality of times. In this case, it becomes possible to form a deep processing groove 35 while suppressing the average output of the laser beam 40.

[0068] Further, the laser beam 40 may be shaped such that the area (irradiated area) of the laminate 13 irradiated with the laser beam 40 is linear or rectangular. In this case, the laser beam 40 is irradiated onto the laminate 13 such that the length direction (longitudinal direction) of the irradiated area is along the width direction of the planned division line 15, and a wide processing groove 35 is formed.

[0069] Furthermore, a plurality of processing grooves 35 may be formed inside each of the planned division lines 15. For example, a pair of processing grooves 35 that are substantially parallel to each other are formed on one end side and the other end side in the width direction of the planned division line 15 (see Fig. 10(C)). In this case, after irradiating the laser beam 40 on one end side of the planned division line 15 to form one processing groove 35, the laser beam 40 is irradiated on the other end side of the planned division line 15 to form the other processing groove 35. Also, by scanning along the planned division line 15 in a state where the laser beam 40 is branched so as to be focused at two locations, a pair of processing grooves 35 can be formed simultaneously.

[0070] When ablation processing is performed on the workpiece 11 or the laminate 13, a melt (debris) of the workpiece 11 or the laminate 13 is generated and scattered. However, if the protective film 33 is formed on the surface 11a side of the workpiece 11, it becomes difficult for the debris to adhere to the workpiece 11 and the laminate 13, and contamination of the workpiece 11 and the device 17 is prevented.

[0071] Thereafter, the same procedure is repeated, and the laser beam 40 is irradiated along the other planned division lines 15. As a result, the processing grooves 35 are formed in a grid pattern along all the planned division lines 15.

[0072] Fig. 7(B) is a cross-sectional view showing a part of the workpiece 11 after the processing groove forming step. By performing the processing groove forming step, the laminate 13 is divided, and the processing grooves 35 reaching the surface 11a side of the workpiece 11 are formed along the planned division lines 15.

[0073] When the processing groove formation step is completed, the protective film 33 is removed. Thereby, foreign matters such as debris attached to the protective film 33 are removed together with the protective film 33. When the protective film 33 is made of a water-soluble resin, the protective film 33 can be easily removed only by supplying a cleaning liquid such as pure water to the workpiece 11, and the process of removing the protective film 33 is simplified.

[0074] In addition, when the amount of debris generated in the processing groove formation step is small, or when the scattering of debris is not a problem, etc., the protective film formation step can also be omitted. In this case, the step of removing the protective film 33 after the processing groove formation step is also omitted.

[0075] Next, a plasma-state etching gas is supplied from the surface 11a side of the workpiece 11 to remove the processing strain or foreign matter remaining in the workpiece 11 or the laminate 13 (plasma etching step). FIG. 8 is a cross-sectional view showing the workpiece 11 in the plasma etching step. In the plasma etching step, the workpiece 11 and the laminate 13 are subjected to plasma etching by the plasma processing apparatus 50. Note that in the plasma etching step, the workpiece 11 may not be supported by the frame 29.

[0076] The plasma processing apparatus 50 includes a chamber 52. The inside of the chamber 52 corresponds to a processing space where plasma processing is performed. An opening 52b through which the workpiece 11 passes when the workpiece 11 is carried in and out is provided in the side wall 52a of the chamber 52.

[0077] Outside the side wall 52a, a gate 54 for opening and closing the opening 52b is provided. Further, an opening and closing unit 56 such as an air cylinder is connected to the gate 54. By moving the gate 54 downward by the opening and closing unit 56 to expose the opening 52b, the workpiece 11 can be carried into the processing space and carried out from the processing space of the workpiece 11. Also, by moving the gate 54 upward by the opening and closing unit 56 to close the opening 52b, the processing space is sealed.

[0078] A pipe 58 such as a pipe is connected to the bottom wall 52c of the chamber 52, and a decompression unit 60 such as an exhaust pump is connected to the pipe 58. When the decompression unit 60 is operated with the opening 52b closed by the gate 54, the inside of the chamber 52 is evacuated and decompressed.

[0079] A table base 62 is provided inside the chamber 52. The table base 62 includes a columnar holding portion 64 and a columnar support portion 66 connected to the holding portion 64. The diameter of the support portion 66 is smaller than the diameter of the holding portion 64, and the support portion 66 is formed downward from the central portion of the lower surface of the holding portion 64.

[0080] A chuck table (holding table) 68 for holding the workpiece 11 is provided on the upper surface of the holding portion 64. The chuck table 68 includes a disk-shaped main body portion 70 made of an insulator, and a plurality of electrodes 72 are embedded inside the main body portion 70. Each of the plurality of electrodes 72 is connected to a DC power source 74 capable of applying a predetermined voltage (for example, a high voltage of about 5 kV) to the electrode 72.

[0081] In addition, a plurality of suction channels 70a that open on the upper surface of the main body portion 70 are provided in the main body portion 70 of the chuck table 68. The suction channels 70a are connected to a suction pump 76 via suction channels 62a formed inside the table base 62.

[0082] When holding the workpiece 11 by the chuck table 68, first, the workpiece 11 is placed on the chuck table 68, and the suction pump 76 is operated. Thereby, the workpiece 11 is sucked on the upper surface of the chuck table 68 by the suction force of the suction pump 76. In this state, when a voltage is applied to the plurality of electrodes 72 by the DC power source 74 to generate a potential difference between the electrodes 72, the workpiece 11 is adsorbed and held by the electrostatic force. Thereby, it becomes possible to hold the workpiece 11 on the chuck table 68 even when the inside of the chamber 52 is decompressed.

[0083] In addition, a flow path 62b is formed inside the table base 62. Both ends of the flow path 62b are connected to a circulation unit 78 that circulates the refrigerant. When the circulation unit 78 is operated, the refrigerant flows from one end of the flow path 62b to the other end, and the table base 62 is cooled.

[0084] A gas supply unit 80 for supplying etching gas is connected to the upper part of the chamber 52. The gas supply unit 80 plasmatizes the etching gas outside the chamber 52 and supplies the plasma-state etching gas into the chamber 52.

[0085] Specifically, the gas supply unit 80 includes a metal supply pipe 82 through which the etching gas supplied to the chamber 52 flows. One end side (downstream side) of the supply pipe 82 is connected to the inside of the chamber 52 through the upper wall 52d of the chamber 52. The other end side (upstream side) of the supply pipe 82 is connected to a gas supply source 90a via a valve 84a, a flow controller 86a, and a valve 88a, connected to a gas supply source 90b via a valve 84b, a flow controller 86b, and a valve 88b, and connected to a gas supply source 90c via a valve 84c, a flow controller 86c, and a valve 88c.

[0086] When predetermined gases are supplied from the gas supply sources 90a, 90b, and 90c at predetermined flow rates, a mixed gas is generated in the supply pipe 82. This mixed gas becomes the etching gas used for etching the workpiece 11. For example, the gas supply source 90a supplies a fluorine-based gas such as SF 6 and so on, the gas supply source 90b supplies oxygen gas (O 2 gas), and the gas supply source 90c supplies an inert gas such as He. However, the components, flow rate ratios, etc. of the gases supplied from the gas supply sources 90a, 90b, and 90c can be arbitrarily changed according to the material of the object to be processed and the processing conditions.

[0087] Further, the gas supply unit 80 includes an electrode 92 that applies a high-frequency voltage to the etching gas generated in the supply pipe 82. The electrode 92 is provided in the middle part of the supply pipe 82 so as to surround the supply pipe 82, and a high-frequency power source 94 is connected to the electrode 92. The high-frequency power source 94 applies a high-frequency voltage having a voltage value of, for example, 0.5 kV or more and 5 kV or less and a frequency of 450 kHz or more and 2.45 GHz or less to the electrode 92.

[0088] When a high-frequency voltage is applied to the etching gas flowing through the supply pipe 82 using the electrode 92 and the high-frequency power source 94, the etching gas changes to a plasma state containing ions and radicals. Then, the etching gas in the plasma state is supplied from the supply port 82a that opens at the downstream end of the supply pipe 82 into the chamber 52. In this way, the etching gas that has been plasmaized outside the chamber 52 is supplied into the chamber 52.

[0089] Inside the upper wall 52d of the chamber 52, a dispersion member 96 is mounted so as to cover the supply port 82a. The etching gas in the plasma state that has flowed into the chamber 52 from the supply pipe 82 is dispersed above the chuck table 68 by the dispersion member 96.

[0090] Also, a pipe 98 such as a tube is connected to the side wall 52a of the chamber 52, and an inert gas supply source (not shown) for supplying an inert gas is connected to the pipe 98. When an inert gas is supplied to the chamber 52 from the inert gas supply source through the pipe 98, the inside of the chamber 52 is filled with the inert gas (inner gas). Note that the pipe 98 may be connected to the gas supply source 90c via a valve (not shown), a flow controller (not shown), etc. In this case, an inert gas is supplied from the gas supply source 90c into the chamber 52 through the pipe 98.

[0091] The etching gas supplied from the gas supply unit 80 is dispersed by a dispersion member 96 provided below the supply port 82a and supplied to the entire workpiece 11 held by the chuck table 68. Then, the plasma-etched gas acts on the workpiece 11 and the laminate 13 (see FIG. 7(B)), and plasma etching is performed on the workpiece 11 and the laminate 13.

[0092] When a gas in a plasma state is supplied to the workpiece 11 and the laminate 13 after the processing groove forming step, the processing strain (processing marks) formed inside the processing groove 35 and around the processing groove 35 by laser processing is removed. In addition, foreign substances such as debris adhering to the workpiece 11 and the laminate 13 are removed. As a result, a decrease in the flexural strength and quality degradation of the device chip finally obtained by dividing the workpiece 11 are suppressed.

[0093] When the etching gas plasmaized outside the chamber 52 passes through the supply pipe 82 made of metal, ions contained in the etching gas are adsorbed on the inner wall of the supply pipe 82, making it difficult to reach the inside of the chamber 52. As a result, an etching gas with a high radical ratio is introduced into the chamber 52 and supplied to the workpiece 11 and the laminate 13. Since an etching gas with a high radical ratio easily enters a narrow region inside the workpiece 11 and the laminate 13, etching treatment is easily performed inside the processing groove 35 (see FIG. 7(B)) by the etching gas.

[0094] When performing the above plasma etching, a mask layer may be formed on the laminate 13. For example, the mask layer is patterned so that a region overlapping the division planned line 15 of the workpiece 11 or the laminate 13 is exposed. By supplying the plasma state etching gas through this mask layer, the region of the workpiece 11 and the laminate 13 where laser processing has been performed is partially etched.

[0095] There are no restrictions on the material or formation method of the mask layer. For example, the mask layer can be formed by a resist made of a photosensitive resin or the like. Also, without removing the protective film 33 (see Fig. 7(B)) after the processing groove formation step, the protective film 33 can be used as the mask layer. In this case, the protective film 33 is removed after the plasma etching step.

[0096] In addition, when the workpiece 11 or the laminate 13 is processed under processing conditions where processing distortion and debris are unlikely to occur in the processing groove formation step, when debris is surely removed by cleaning after the processing groove formation step, or when there are no problems with the operation and quality of the device chip even if processing distortion and debris remain in the workpiece 11 or the laminate 13, the plasma etching step may be omitted.

[0097] Next, a resin layer is formed on the surface 11a side of the workpiece 11 (resin layer formation step). Fig. 9 is a perspective view showing the workpiece 11 in the resin layer formation step.

[0098] The resin layer 37 corresponds to an underfill material when mounting the device chips obtained by dividing the workpiece 11. For example, NCF (Non Conductive Film) is used as the resin layer 37. NCF is a film obtained by molding resin into a sheet shape and has adhesiveness and insulation properties.

[0099] The resin layer 37 (NCF) is formed to have approximately the same diameter as the workpiece 11 and is adhered to the surface 11a side of the workpiece 11 so as to cover the entire laminate 13. Thereby, the resin layer 37 is formed on the surface 11a side of the workpiece 11, and the device 17 and the connection electrodes 19 are sealed by the resin layer 37.

[0100] However, there is no limitation on the type of the resin layer 37. For example, the resin layer 37 may be formed by applying NCP (Non Conductive Paste) on the surface 11a side of the workpiece 11. Also, there is no limitation on the material of the resin layer 37. For example, a resin layer 37 mainly composed of an epoxy resin, an acrylic resin, a urethane resin, a silicone resin, a polyimide resin, etc. is used. Further, the resin layer 37 may contain various additives such as an oxidizing agent and a filler.

[0101] Through the above steps, a wafer (grooved wafer) is obtained which includes the workpiece 11, the laminate 13, and the resin layer 37, and in which a processing groove 35 for dividing the laminate 13 is provided along the division planned line 15. That is, the above steps correspond to a method for manufacturing a grooved wafer.

[0102] Next, the workpiece 11 and the resin layer 37 are divided along the division planned line 15 (division step). FIG. 10(A) is a cross-sectional view showing the workpiece 11 in the division step. For example, in the division step, the workpiece 11 and the resin layer 37 are cut by a cutting device 100.

[0103] The cutting device 100 includes a chuck table (holding table) 102 for holding the workpiece 11. The upper surface of the chuck table 32 is a circular flat surface generally parallel to the horizontal direction (XY plane direction), and constitutes a holding surface 102a for holding the workpiece 11. The holding surface 102a is connected to a suction source (not shown) such as an ejector via a flow path (not shown), a valve (not shown), etc. formed inside the chuck table 102.

[0104] A ball screw type moving mechanism (not shown) for moving the chuck table 102 along the X-axis direction is connected to the chuck table 102. Also, a rotation drive source (not shown) such as a motor for rotating the chuck table 102 around a rotation axis generally perpendicular to the holding surface 102a is connected to the chuck table 102. Further, a plurality of clamps 104 for gripping and fixing the frame 29 are provided around the chuck table 102.

[0105] Above the chuck table 102, a cutting unit 106 is provided. The cutting unit 106 includes a cylindrical housing 108. The housing 108 houses a columnar spindle 110 arranged along the Y-axis direction. The tip (one end) of the spindle 110 is exposed outside the housing 108, and a rotational drive source such as a motor is connected to the base end (the other end) of the spindle 110.

[0106] An annular cutting blade 112 is mounted on the tip of the spindle 110. The cutting blade 112 rotates around a rotation axis substantially parallel to the Y-axis direction by the power transmitted from the rotational drive source via the spindle.

[0107] As the cutting blade 112, for example, a hub type cutting blade (hub blade) is used. The hub blade is configured by integrating an annular base made of metal or the like and an annular cutting edge formed along the outer peripheral edge of the base. The cutting edge of the hub blade is constituted by an electroformed grindstone including abrasive grains made of diamond or the like and a binder such as a nickel plating layer for fixing the abrasive grains. However, a washer type cutting blade (washer blade) can also be used as the cutting blade 112. The washer blade is constituted only by an annular cutting edge including abrasive grains and a binder made of metal, ceramics, resin, or the like for fixing the abrasive grains.

[0108] A ball screw type moving mechanism (not shown) is connected to the cutting unit 106. This moving mechanism moves the cutting unit 106 along the Y-axis direction and raises and lowers it along the Z-axis direction.

[0109] In the dividing step, first, the workpiece 11 is held by the chuck table 102. Specifically, the workpiece 11 is placed on the chuck table 102 such that the surface 11a side (the laminate 13 side, the resin layer 37 side) faces upward and the back surface 11b side (the tape 31 side) faces the holding surface 102a. Also, the frame 29 is fixed by a plurality of clamps 104. In this state, when the suction force (negative pressure) of the suction source is applied to the holding surface 102a, the workpiece 11 is held by the chuck table 102 via the tape 31.

[0110] Next, the chuck table 102 is rotated to align the length direction of the predetermined dividing line 15 with the machining feed direction (X-axis direction). Also, the position of the cutting unit 106 in the indexing feed direction (Y-axis direction) is adjusted so that the cutting blade 112 is disposed on the extension line of the predetermined dividing line 15. Further, the height of the cutting unit 106 is adjusted so that the lower end of the cutting blade 112 is disposed below the upper surface of the tape 31. The height difference between the upper surface of the resin layer 37 and the lower end of the cutting blade 112 at this time corresponds to the cutting depth of the cutting blade 112.

[0111] Then, while rotating the cutting blade 112, the chuck table 102 is moved along the X-axis direction. As a result, the chuck table 102 and the cutting blade 112 relatively move along the X-axis direction (machining feed), and the cutting blade 112 cuts into the workpiece 11, the pattern layer 27, and the resin layer 37 along the dividing line 15. As a result, the workpiece 11, the pattern layer 27, and the resin layer 37 are divided along the dividing line 15. Thereafter, the same procedure is repeated to cut the workpiece 11, the pattern layer 27, and the resin layer 37 along all the dividing lines 15.

[0112] FIG. 10(B) is a cross-sectional view showing a part of the workpiece 11 in which a kerf (cut) 39 is formed inside the processing groove 35. In the workpiece 11, the pattern layer 27, and the resin layer 37 after cutting, kerfs 39 extending from the upper surface of the resin layer 37 to the lower surface of the pattern layer 27 are formed in a grid pattern along the division planned line 15. As a result, a plurality of device chips 41 each including the device 17 and pieces of the pattern layer 27 and the resin layer 37 are manufactured.

[0113] In the dividing step, the positional relationship between the chuck table 102 and the cutting blade 112 is adjusted so that the cutting blade 112 cuts into the inside of the processing groove 35 (between both ends in the width direction of the processing groove 35) corresponding to the region where the laminate 13 has been removed. Therefore, the cutting blade 112 cuts the workpiece 11 and the like without contacting the laminate 13. Thereby, it is possible to avoid the rotating cutting blade from contacting the laminate 13 and causing film peeling in the laminate 13, and damage to the device 17, peeling of the resin layer 37, etc. are prevented.

[0114] FIG. 10(C) is a cross-sectional view showing a part of the workpiece 11 in which a kerf 39 is formed between a pair of processing grooves 35. When a pair of processing grooves 35 are formed in the workpiece 11 and the laminate 13, the positional relationship between the chuck table 102 and the cutting blade 112 is adjusted so that the cutting blade 112 cuts between the pair of processing grooves 35. Thereby, it is possible to avoid the film peeling of the laminate 13 from propagating to the region corresponding to the device 17.

[0115] Pieces of the resin layer 37 are attached to the device chips 41 obtained by dividing the workpiece 11 and the like. Then, the device chips 41 are mounted on a mounting substrate or other device chips via the pieces of the resin layer 37. That is, the pieces of the resin layer 37 function as an underfill material.

[0116] Note that the workpiece 11, the pattern layer 27, and the resin layer 37 may be cut simultaneously with other layers or individually. For example, the resin layer 37 may be cut with a first cutting blade, and then the workpiece 11 and the pattern layer 27 may be cut with a second cutting blade. In this case, the first cutting blade and the second cutting blade may be the same cutting blade or different cutting blades.

[0117] Here, if the resin layer 37 is formed before the formation of the processing groove 35 and the laser beam 40 (see FIG. 7(A)) for forming the processing groove 35 is irradiated onto the laminate 13 through the resin layer 37, the resin layer 37 may be deteriorated and hardened due to the heat and debris generated by the irradiation of the laser beam 40, and the flexibility of the resin layer 37 may be lost. In this case, when mounting the device chip 41, the individual pieces of the resin layer 37 are less likely to deform, and there is a possibility that the connection between the connection electrode 19 of the device chip 41 and the electrode of the mounting destination cannot be made or becomes incomplete.

[0118] However, in the present embodiment, after the step of forming the processing groove 35 by irradiating the laser beam 40 (see FIG. 7(A)), the step of forming the resin layer 37 (see FIG. 9) is performed. Thereby, deterioration of the resin layer 37 due to irradiation of the laser beam can be avoided, and bonding failure of the device chip 41 can be prevented.

[0119] Note that, in the above, the form in which the workpiece 11 etc. are cut and divided by the cutting blade 112 has been described, but the dividing method is not limited to cutting. For example, when the pattern layer 27 is not formed on the back surface 11b side of the workpiece 11, the workpiece 11 etc. can also be divided using cutting and grinding.

[0120] Specifically, first, instead of forming the kerf 39, the workpiece 11 and the resin layer 37 are cut with a cutting blade 112 to form cutting grooves along the division planned lines 15. At this time, the cutting depth of the cutting blade 112 is adjusted so that the lower end of the cutting blade 112 is positioned below the surface 11a of the workpiece 11 and above the back surface 11b. As a result, cutting grooves that divide the resin layer 37 and reach the inside of the workpiece 11 are formed along each division planned line 15.

[0121] Next, the back surface 11b side of the workpiece 11 is ground and thinned. For grinding the workpiece 11, for example, a grinding device 2 (see Fig. 3(A)) is used. When the workpiece 11 is ground until the cutting grooves are exposed on the back surface 11b side of the workpiece 11, the workpiece 11 is divided into a plurality of device chips 41. As a result, device chips 41 to which pieces of the resin layer 37 are attached are manufactured.

[0122] Note that the above cutting grooves can also be formed before the formation of the resin layer 37. Specifically, first, the above cutting process is performed on the workpiece 11 (see Fig. 7(B)) in which the processing groove 35 is formed, and cutting grooves reaching the inside of the workpiece 11 are formed along each division planned line 15. Next, the resin layer 37 is formed on the surface 11a side of the workpiece 11 (see Fig. 9). Then, the workpiece 11 is ground until the cutting grooves are exposed on the back surface 11b side of the workpiece 11, and the workpiece 11 is divided into a plurality of device chips 41.

[0123] Next, the resin layer 37 is divided along the division planned lines 15. Note that there is no limitation on the method of dividing the resin layer 37. For example, the resin layer 37 is divided by cutting with a cutting blade or ablation processing by irradiation with a laser beam. Also, as described later, the resin layer 37 may be divided by applying an external force by expanding an expandable sheet. As a result, device chips 41 to which pieces of the resin layer 37 are attached are manufactured.

[0124] Further, for example, in the dividing step, after forming a dividing starting point (a trigger for division) on the workpiece 11, an external force may be applied to the workpiece 11 to divide the workpiece 11 or the like. Hereinafter, specific examples of a method for dividing the workpiece 11 or the like by forming a dividing starting point and applying an external force will be described.

[0125] First, before the dividing step, an expandable sheet (expansion sheet) having extensibility is attached to the workpiece 11 (expansion sheet attaching step). For example, as the tape 31 (see FIG. 5), an expandable sheet that can be expanded by applying an external force is used. In this case, the workpiece 11 is supported by the frame 29 via the expandable sheet. As the base material of the expandable sheet, it is preferable to use a resin such as polyolefin or polyvinyl chloride that is rich in extensibility.

[0126] However, the expandable sheet may be a sheet different from the tape 31. For example, before the dividing step, the tape 31 may be peeled off from the workpiece 11, and a separate expandable sheet may be attached to the workpiece 11.

[0127] Next, the dividing step is performed. In the dividing step, first, the workpiece 11 is irradiated with a laser beam to form a modified layer along the division planned line 15 on the workpiece 11 (modified layer forming step). FIG. 11(A) is a cross-sectional view showing the workpiece 11 in the modified layer forming step.

[0128] In the modified layer forming step, laser processing is performed on the workpiece 11 by the laser processing apparatus 120. The configuration of the laser processing apparatus 120 is the same as that of the laser processing apparatus 30 (see FIG. 7(A)). Specifically, the laser processing apparatus 120 includes a chuck table (holding table) 122, a plurality of clamps 124, and a laser irradiation unit 126. The chuck table 122 includes a holding surface 122a for holding the workpiece 11, and the laser irradiation unit 126 includes a laser oscillator (not shown) and a laser processing head 128. Note that the laser processing apparatus 30 (see FIG. 7(A)) can also be used in the modified layer forming step.

[0129] In the modified layer forming step, first, the workpiece 11 is held by the chuck table 122. Specifically, the workpiece 11 is placed on the chuck table 122 such that the surface 11a side (the laminate 13 side, the resin layer 37 side) faces the holding surface 122a and the back surface 11b side (the tape 31 side) faces upward. Also, the frame 29 is fixed by a plurality of clamps 124. In this state, when the suction force (negative pressure) of the suction source is applied to the holding surface 122a, the workpiece 11 is suction-held by the chuck table 122 via the resin layer 37.

[0130] Note that a protective member for protecting the surface of the resin layer 37 may be provided on the resin layer 37. In this case, the workpiece 11 is held by the chuck table 122 via the resin layer 37 and the protective member. Thereby, contact between the resin layer 37 and the holding surface 122a of the chuck table 122 can be avoided. Note that examples of the material of the protective member are the same as those of the support member 23 (see FIG. 5).

[0131] Next, the chuck table 122 is rotated to align the length direction of the predetermined division line 15 with the machining feed direction (X-axis direction). Also, the position in the indexing feed direction (Y-axis direction) of the chuck table 122 is adjusted so that the position in the Y-axis direction of the region irradiated with the laser beam 130 coincides with the region inside both ends in the width direction of the predetermined division line 15 (for example, the center in the width direction of the machining groove 35). Further, the position of the laser processing head 128 and the arrangement of the optical system are adjusted so that the focal point of the laser beam 130 is positioned at the same height as the inside of the workpiece 11.

[0132] While irradiating the laser beam 130 from the laser processing head 128, the chuck table 122 is moved along the processing feed direction (X-axis direction). As a result, the chuck table 122 and the laser beam 130 relatively move at a predetermined speed (processing feed speed) along the processing feed direction (X-axis direction). Consequently, the laser beam 130 is irradiated along the division planned line 15 from the back surface 11b side of the workpiece 11 with the focusing point positioned inside the workpiece 11.

[0133] Note that the irradiation conditions of the laser beam 130 are set such that the area of the workpiece 11 irradiated with the laser beam 130 is modified and altered by multi-photon absorption. Specifically, the wavelength of the laser beam 130 is set such that at least a part of the laser beam 130 penetrates the workpiece 11. That is, the laser beam 130 is a laser beam having a wavelength that is transmissive to the workpiece 11. Also, the irradiation conditions of the other laser beam 130 are set such that the workpiece 11 is appropriately modified. For example, when the workpiece 11 is a silicon wafer, the irradiation conditions of the laser beam 130 are set as follows. Wavelength: 1064 nm Average output: 1 W Repetition frequency: 100 kHz Processing feed speed: 800 mm / s

[0134] When the laser beam 130 irradiates the workpiece 11, the inside of the workpiece 11 is modified and altered by multi-photon absorption, and a modified layer (altered layer) 43 is formed inside the workpiece 11 along the division planned line 15 and the processing groove 35. Thereafter, by repeating the same procedure, the laser beam 130 is irradiated along the other division planned lines 15 and the processing grooves 35. As a result, a lattice-shaped modified layer 43 is formed inside the workpiece 11.

[0135] Note that a plurality of modified layers 43 may be formed in the thickness direction of the workpiece 11. For example, when the workpiece 11 is a silicon wafer or the like having a thickness of 200 μm or more, forming two or more modified layers 43 makes it easier to appropriately divide the workpiece 11. When forming a plurality of modified layers 43, while changing the condensing point of the laser beam 130 in the thickness direction of the workpiece 11, the laser beam 130 is irradiated a plurality of times along each division planned line 15.

[0136] FIG. 11(B) is a cross-sectional view showing a part of the workpiece 11 after the modified layer forming step. The modified layer 43 is formed along the division planned line 15 and the processing groove 35 in a region where the laser beam 130 (see FIG. 11(A)) inside the workpiece 11 is condensed or in the vicinity thereof. Further, when the modified layer 43 is formed, cracks 45 are generated in the modified layer 43, and the cracks 45 progress from the modified layer 43 toward the front surface 11a and the back surface 11b of the workpiece 11.

[0137] The region of the workpiece 11 where the modified layer 43 and the cracks 45 are formed becomes more brittle than other regions of the workpiece 11. Therefore, when an external force is applied to the workpiece 11, the workpiece 11 is divided along the division planned line 15 and the processing groove 35 starting from the modified layer 43 and the cracks 45. That is, the modified layer 43 and the cracks 45 function as division starting points.

[0138] However, depending on the irradiation conditions of the laser beam 130, the thickness of the workpiece 11, etc., the cracks 45 may reach the front surface 11a and the back surface 11b of the workpiece 11. In this case, the workpiece 11 is divided along the division planned line 15 in the modified layer forming step.

[0139] Next, the tape 31 (expansion sheet) is expanded (expansion step). FIG. 12(A) is a cross-sectional view showing the workpiece 11 in the expansion step.

[0140] In the expansion step, the tape 31 is expanded by pulling it radially outward. As a result, an external force is applied to the workpiece 11, the pattern layer 27, and the resin layer 37, and the workpiece 11, the pattern layer 27, and the resin layer 37 are divided along the division planned line 15.

[0141] The expansion of the tape 31 may be performed manually by an operator or automatically using a dedicated expansion device. Fig. 12(A) shows an example in which the tape 31 is expanded by the expansion device 140.

[0142] The expansion device 140 has a drum 142 formed in a hollow cylindrical shape. A plurality of rollers 144 are arranged along the circumferential direction of the drum 142 at the upper end of the drum 142. In addition, a plurality of columnar support members 146 are arranged outside the drum 142. Air cylinders (not shown) for moving (lifting and lowering) the support members 146 along the vertical direction are connected to the lower ends of the support members 146, respectively.

[0143] An annular table 148 is fixed to the upper ends of the plurality of support members 146. A circular opening penetrating the table 148 in the thickness direction is provided at the center of the table 148. Note that the diameter of the opening of the table 148 is larger than the diameter of the drum 142, and the upper end of the drum 142 can be inserted into the opening of the table 148. In addition, a plurality of clamps 150 for gripping and fixing the frame 29 are arranged on the outer peripheral portion of the table 148.

[0144] When dividing the workpiece 11, first, the support member 146 is moved by an air cylinder (not shown) so that the upper end of the roller 144 and the upper surface of the table 148 are arranged at substantially the same height position. Then, the frame 29 is arranged on the table 148 and fixed by the plurality of clamps 150. At this time, the workpiece 11 is arranged so as to overlap the region inside the drum 142.

[0145] Next, the support member 146 is lowered by an air cylinder (not shown), and the table 148 is pulled down. As a result, the tape 31 is pulled radially outward while being supported by the roller 144. Consequently, the tape 31 is radially expanded.

[0146] FIG. 12(B) is a cross-sectional view showing a part of the workpiece 11 after the expansion step. When the tape 31 is expanded, an external force is applied to the workpiece 11 to which the tape 31 is adhered. As a result, the modified layer 43 or the crack 45 (see FIG. 11(B)) functions as a splitting starting point, and the workpiece 11 is split along the splitting planned line 15. Also, the pattern layer 27 and the resin layer 37 formed on the workpiece 11 are split along the splitting planned line 15 together with the workpiece 11.

[0147] Note that the region of the laminate 13 that overlaps with the modified layer 43 has been removed in the groove forming step (see FIGS. 7(A) and 7(B)). Therefore, when the workpiece 11 is split, the phenomenon in which the thin film included in the laminate 13 is peeled off due to being induced by the breakage of the laminate 13 hardly occurs, and damage to the device 17 is prevented.

[0148] When the workpiece 11 or the like is split along the splitting planned line 15, a plurality of device chips 41 in which the device 17 is sealed by pieces of the resin layer 37 are manufactured. Also, due to the expansion of the tape 31, a gap is formed between the device chips 41. Then, the device chips 41 are peeled off from the tape 31 and picked up, and mounted on a mounting substrate or other device chips.

[0149] Note that when the crack 45 (see FIG. 11(B)) reaches the front surface 11a and the back surface 11b of the workpiece 11 when the modified layer 43 is formed, the workpiece 11 has already been split along the splitting planned line 15 before the expansion step is performed. In this case, when the resin layer 37 is divided along the splitting planned line 15 by the expansion of the tape 31, a gap is formed between the device chips 41.

[0150] As described above, in the method for manufacturing a device chip according to the present embodiment, before dividing the workpiece 11, a processing groove 35 for dividing the laminate 13 is formed along the planned division line 15. Thereby, peeling of the laminate 13 at the time of dividing the workpiece 11 is avoided, and damage to the device 17 and peeling of the resin layer 37 are prevented.

[0151] Further, in the method for manufacturing a device chip according to the present embodiment, after a processing groove 35 for dividing the laminate 13 is formed along the planned division line 15 by irradiation with a laser beam 40, a resin layer 37 is formed on the surface 11a side of the workpiece 11. Thereby, it is possible to avoid the resin layer 37 from being irradiated with the laser beam 40 for forming the processing groove 35 and being altered, and bonding failure when mounting the device chip 41 via pieces of the resin layer 37 is prevented.

[0152] Furthermore, in the method for manufacturing a device chip according to the present embodiment, before the processing groove 35 is formed by irradiation with the laser beam 40, fixing of the support member 23 (see FIG. 2(A)), grinding of the workpiece 11 (see FIG. 3(A)), and removal of the support member 23 (see FIG. 5) are performed. Thereby, it is possible to avoid the adhesive layer 25 for fixing the support member 23 from entering the processing groove 35 and making it difficult to remove the support member 23 from the workpiece 11.

[0153] Note that the structure, method, etc. according to the above embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

Explanation of Reference Numerals

[0154] 11 Workpiece 11a Surface (first surface) 11b Back surface (second surface) 13 Laminate 15 Planned division line (street) 17 Device 19 Connection electrode (bump) 21 Electrode (embedded electrode, through electrode) 23 Support member 25 Adhesive layer 27 Pattern layer 29 Frame 29a Opening 31 Tape 33 Protective film 35 Machining groove 37 Resin layer 39 Kerf (cut) 41 Device chip 43 Modified layer (altered layer) 45 Crack 2 Grinding device 4 Chuck table (holding table) 4a Holding surface 6 Grinding unit 8 Spindle 10 Mount 12 Grinding wheel 14 Base 16 Grinding stone 20 Spin coater 22 Spinner table (chuck table) 22a Holding surface 24 Clamp 26 Protective film material supply unit 28 Protective film material 30 Laser processing device 32 Chuck table (holding table) 32a Holding surface 34 Clamp 36 Laser irradiation unit 38 Laser processing head 40 Laser beam 50 Plasma processing device 52 Chamber 52a Side wall 52b Opening 52c Bottom wall 52d Top wall 54 Gate 56 Opening / closing unit 58 Pipe 60 Vacuum unit 62 Table base 62a Suction path 62b Flow path 64 Holding part 66 Support part 68 Chuck table (holding table) 70 Main body part 70a Suction path 72 Electrode 74 DC power supply 76 Suction pump 78 Circulation unit 80 Gas supply unit 82 Supply pipe 82a Supply port 84a, 84b, 84c Valve 86a, 86b, 86c Flow controller 88a, 88b, 88c Valve 90a, 90b, 90c Gas supply source 92 Electrode 94 High-frequency power supply 96 Dispersion member 98 Pipe 100 Cutting device 102 Chuck table (holding table) 102a Holding surface 104 Clamp 106 Cutting unit 108 Housing 110 Spindle 112 Cutting blade 120 Laser processing device 122 Chuck table (holding table) 122a Holding surface 124 Clamp 126 Laser irradiation unit 128 Laser processing head 130 Laser beam 140 Expansion device 142 Drum 144 Roller 146 Support member 148 Table 150 Clamp

Claims

1. A method for manufacturing a device chip by dividing a workpiece having a laminate provided on a surface side thereof, the laminate constituting a device provided in a plurality of regions partitioned by a plurality of intersecting planned division lines, the method comprising: a support member fixing step of fixing a support member to the surface side of the workpiece; a back grinding step of grinding the back surface side of the workpiece after the support member fixing step; a support member removing step of removing the support member from the surface side of the workpiece after the back grinding step; a processing groove forming step of irradiating a laser beam having an absorbable wavelength with respect to the laminate from the surface side of the workpiece along the planned division line to form a processing groove for dividing the laminate along the planned division line; a resin layer forming step of forming a resin layer on the surface side of the workpiece after the processing groove forming step; a dividing step of dividing the workpiece and the resin layer along the planned division line, the method for manufacturing a device chip being characterized by including the steps.

2. The method for manufacturing a device chip according to claim 1, further comprising a back surface pattern forming step of forming a pattern on the back surface side of the workpiece after the back grinding step.

3. The method for manufacturing a device chip according to claim 1 or 2, further comprising a protective film forming step of forming a protective film on the surface side of the workpiece before the processing groove forming step.

4. The method for manufacturing a device chip according to any one of claims 1 to 3, further comprising a plasma etching step of supplying an etching gas in a plasma state from the surface side of the workpiece to remove processing strain or foreign matter remaining in the workpiece or the laminate after the processing groove forming step.

5. The method for manufacturing a device chip according to any one of claims 1 to 4, wherein in the dividing step, the workpiece and the resin layer are cut along the planned division line with a cutting blade.

6. Before the dividing step, the method further includes an expand sheet attaching step of attaching an expandable sheet having extensibility to the workpiece, The dividing step includes: a modified layer forming step of forming a modified layer along the planned division line in the workpiece by irradiating a laser beam having a wavelength permeable to the workpiece with the condensing point of the laser beam positioned inside the workpiece. After the modified layer forming step, an expanding step of expanding the expanded sheet, and a method for manufacturing a device chip according to any one of claims 1 to 4, characterized in that it comprises.

Images