Tape extension method

Abstract

To prevent scattering of small pieces of film glue during breakage of the film glue.SOLUTION: There is provided a tape extension method for extending a tape that is pasted to the rear side of a workpiece with film glue and has a larger size than that of the workpiece, and the tape extension method includes: a center position detection step of detecting a center position in a radial direction of the circular film glue having a diameter equal to or less than an outer diameter of the workpiece and equal to or more than the outer diameter of a device area, and a center position in a radial direction of the workpiece; a film glue pasting step of pasting the film glue to the rear face of the workpiece so that the center position in the radial direction of the film glue and the center position of the rear face correspond to each other; and an extension step of extending the tape to divide the workpiece into a plurality of pieces of device chips or extending the interval between the plurality of pieces of device chips that are already divided into pieces, and breaking the film glue along a plurality of division scheduled lines.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tape expansion method for expanding a tape adhered to the back side of a workpiece via a film-like adhesive.

Background Art

[0002] Device chips are widely used in electronic devices such as mobile phones and personal computers. For example, a device chip is manufactured by thinning the back side of a wafer in which a plurality of division planned lines are set in a grid pattern on the surface and devices such as ICs (Integrated Circuits) are formed in each region partitioned by the plurality of division planned lines, and then dividing the wafer along each division planned line (performing dicing).

[0003] For example, a film-like adhesive having a thickness of about 20 μm to 100 μm and formed of a thermosetting resin such as an epoxy resin is adhered to the back side of a device chip, and the device chip is mounted on a die bonding frame or the like via this film-like adhesive.

[0004] The film-like adhesive is adhered to the back side of the wafer, for example, before the wafer is divided. At the time of dividing (dicing) the wafer, the entire film-like adhesive is cut in the thickness direction together with the wafer (see, for example, Patent Document 1).

[0005] In addition, a method of forming a cut residue portion in a part of the thickness direction of the film-like adhesive at the time of dividing the wafer has also been proposed (see, for example, Patent Document 2). In this case, after the wafer is divided, the dicing tape is expanded in the radial direction, so that the film-like adhesive is broken.

[0006] The film-shaped adhesive is also called a die bonding film, a die attach film, etc., and is generally sold as a circular integrated tape in which the film-shaped adhesive is laminated on a circular dicing tape. However, the film-shaped adhesive is provided in a predetermined region (for example, a circular region) smaller than the outer diameter of the dicing tape at the central portion of the dicing tape.

[0007] When attaching the integrated tape to the back side of the wafer, the outer peripheral portion of the integrated tape (that is, the outer peripheral portion of the dicing tape) is attached to one surface of a metal annular frame, and a predetermined region at the central portion of the integrated tape (that is, the film-shaped adhesive) is attached to the back side of the wafer to form a wafer unit.

[0008] Since such an attaching operation is usually automatically performed using an attaching device, a film-shaped adhesive having an outer diameter several millimeters larger than the outer diameter of the wafer is used in consideration of the positional deviation between the wafer and the film-shaped adhesive. Therefore, when the film-shaped adhesive of the integrated tape is attached to the wafer, the outer peripheral portion of the film-shaped adhesive protrudes outside the wafer.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0010] When the wafer is divided and then the dicing tape is radially expanded to break the film-shaped adhesive, the outer peripheral portion of the film-shaped adhesive protruding outside the wafer may be broken into small pieces and scattered.

[0011] Particularly, when scattered chips adhere to the surface of a device chip or the like, it may cause chip defects. The present invention has been made in view of such problems, and an object thereof is to suppress scattering of pieces of a film-like adhesive when the film-like adhesive breaks.

Means for Solving the Problems

[0012] According to one aspect of the present invention, there is provided a tape expansion method for expanding a tape having a size larger than that of a workpiece, which is adhered via a film-like adhesive to the back surface of a disk-shaped workpiece having, on the front surface side, a device region in which devices are provided in each of a plurality of regions partitioned by a plurality of division planned lines set in a lattice pattern, and an outer peripheral surplus region surrounding the device region. The method includes a center position detection step of detecting a radial center position of a circular film-like adhesive having a diameter equal to or less than the outer diameter of the workpiece and equal to or greater than the outer diameter of the device region, and a radial center position of the workpiece; a film-like adhesive attachment step of attaching the film-like adhesive to the back surface of the workpiece such that the detected radial center positions of the film-like adhesive and the back surface correspond to each other after the center position detection step; and an expansion step of fragmenting the workpiece into a plurality of device chips or expanding the interval between the plurality of already fragmented device chips by expanding the tape, and breaking the film-like adhesive along the plurality of division planned lines. , in the center position detection step, using a laser sensor unit having a laser oscillator that emits a laser beam and a light receiving element that receives the laser beam, detect three or more points on the outer peripheral edge of the film-shaped adhesive and three or more points on the outer peripheral edge of the workpiece, calculate the radial center position of the film-shaped adhesive from the detected plurality of points on the outer peripheral edge of the film-shaped adhesive, and calculate the radial center position of the workpiece from the detected plurality of points on the outer peripheral edge of the workpiece. A tape expansion method is provided.

Advantages of the Invention

[0014] In the tape expansion method according to one aspect of the present invention, a circular film-like adhesive having a diameter equal to or less than the outer diameter of the workpiece and equal to or greater than the outer diameter of the device region is used. In the film-like adhesive attachment step, the film-like adhesive is attached to the back surface of the workpiece such that the detected radial center positions of the film-like adhesive and the workpiece correspond to each other. Therefore, the outer peripheral edge of the film-like adhesive does not protrude from the outer peripheral edge of the workpiece.

[0015] Then, in the expanding step, by expanding the tape adhered to the back side of the workpiece via the film-like adhesive, the film-like adhesive is broken along a plurality of planned dividing lines of the workpiece. In the expanding step, since the film-like adhesive is broken with the outer peripheral edge of the film-like adhesive not protruding from the outer peripheral edge of the workpiece, scattering of small pieces of the film-like adhesive can be suppressed.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0017] With reference to the accompanying drawings, embodiments according to one aspect of the present invention will be described. FIG. 1 is a flowchart of a tape extension method in this embodiment. In this tape extension method, a tape extension device 2 shown in FIG. 2(A) etc. is used.

[0018] As shown in FIG. 2(A), the tape extension device 2 has a disk-shaped holding table (chuck table) 4 having a diameter smaller than that of the disk-shaped workpiece 11. The holding table 4 has a disk-shaped metal frame.

[0019] The frame has a disk-shaped recess, and a porous plate (not shown) made of porous ceramics is fixed to the recess. A flow path is formed in the frame, and a suction source (not shown) such as an ejector is connected to the flow path.

[0020] Due to the negative pressure transmitted from a suction source (not shown) such as an ejector to the porous plate, a negative pressure is generated on the upper surface of the porous plate. The upper surface of the porous plate and the upper surface of the frame are flush with each other, forming a substantially flat holding surface 4a.

[0021] On the holding surface 4a, the surface 11a side of the disk-shaped workpiece 11 is suction-held. Note that since the outer diameter of the holding surface 4a is smaller than the outer diameter of the workpiece 11, the outer peripheral end portion of the workpiece 11 held by the holding surface 4a protrudes outside the holding surface 4a.

[0022] At the central portion of the bottom surface of the holding table 4, a rotating shaft 6 of a rotation mechanism (not shown) is connected concentrically with the holding surface 4a. By rotating the rotating shaft 6, the holding table 4 rotates around the rotating shaft 6.

[0023] At the side portion of the holding table 4, the base ends of four arm portions (not shown) are fixed in a manner protruding in the radial direction of the holding table 4. At the tip of each arm portion, a clamp (not shown) for sandwiching a rectangular expandable tape (tape) 19 described later is provided.

[0024] Above a predetermined position outside the holding surface 4a, a light source unit 8a is provided. The light source unit 8a has a laser diode (laser oscillator) 8a1 that emits a laser beam L having a wavelength in the visible light band (for example, a wavelength of 660 nm).

[0025] The laser beam L emitted from the laser diode 8a1 passes through optical elements such as a polygon mirror (not shown), a fixed mirror 8a2, an fθ lens, etc. (not shown) in sequence, and is irradiated downward of the holding table 4.

[0026] Immediately below the light source unit 8a, a light receiving unit 8b capable of receiving the laser beam L irradiated from the light source unit 8a is arranged. The light receiving unit 8b is provided separately and independently from the holding table 4 in a manner that does not interfere with the above-mentioned arm portion.

[0027] The light receiving unit 8b has a condenser lens (not shown), and the laser beam L transmitted through the condenser lens is received by a light receiving element 8b1 such as a CCD (Charge-Coupled Device). The light source unit 8a and the light receiving unit 8b constitute a laser sensor unit 8.

[0028] The light source unit 8a irradiates the laser beam L to the outer peripheral portion of the workpiece 11 in a stationary state held by the holding surface 4a. The laser beam L is irradiated so as to scan a predetermined length range of the outer peripheral portion of the workpiece 11 along the radial direction of the holding surface 4a.

[0029] The laser beam L irradiated to the workpiece 11 is reflected by the workpiece 11, but the laser beam L irradiated outside the workpiece 11 enters the light receiving unit 8b. A control unit (described later) is connected to the laser sensor unit 8.

[0030] The control unit specifies the switching position of light and darkness received by the light receiving unit 8b as the edge position of the workpiece 11. The edge position is stored in the control unit as XY coordinates with the center of the holding surface 4a as the origin.

[0031] The control unit is configured by a computer including, for example, a processor (processing device) typified by a CPU (Central Processing Unit), a main memory device such as a DRAM (Dynamic Random Access Memory), and an auxiliary storage device such as a flash memory. Software including a predetermined program is stored in the auxiliary storage device.

[0032] By operating the processing device and the like according to this software, the functions of the control unit are realized. In addition to calculating the edge position, the control unit controls the operations of the components of the tape expansion device 2 such as the holding table 4, the rotation mechanism, and the laser sensor unit 8.

[0033] Incidentally, the workpiece 11 of the present embodiment is a semiconductor wafer mainly formed of silicon (Si). Note that there are no restrictions on the material, structure, size, etc. of the workpiece 11. For example, wafers formed of gallium arsenide (GaAs) or silicon carbide (SiC) other than silicon can also be used as the workpiece 11.

[0034] As shown in FIG. 2(B), a plurality of division planned lines (streets) 13 are set in a grid pattern on the surface 11a of the workpiece 11. Devices 15 such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are formed in each of the plurality of regions partitioned by the plurality of division planned lines 13.

[0035] The region on the surface 11a side where the plurality of devices 15 are provided is the device region 15a. Around the device region 15a, there is a substantially flat outer peripheral surplus region 15b where no devices 15 are provided so as to surround the device region 15a. A notch indicating the crystal orientation of the workpiece 11 is formed in the outer peripheral surplus region 15b.

[0036] On the surface 11a side of the workpiece 11, a resin protection tape 17 (omitted in FIG. 2(B)) is adhered. The protection tape 17 is used to protect the surface 11a side when forming a modified layer on the thinned workpiece 11 or when thinning the workpiece 11 by grinding, etc.

[0037] The modified layer is formed along the planned division line 13 at a predetermined depth in the thickness direction of the workpiece 11. The modified layer is a fragile region with lower mechanical strength compared to other regions of the workpiece 11 where the modified layer is not formed.

[0038] In this embodiment, the modified layer is formed after the workpiece 11 is thinned. Although cracks extend on the surface 11a side and the back surface 11b side starting from the modified layer, the cracks do not reach the surface 11a and the back surface 11b. Therefore, the workpiece 11 is not separated into individual pieces in units of the device 15.

[0039] However, the workpiece 11 may form a modified layer before grinding the back surface 11b side, and further, by grinding the back surface 11b side after the formation of the modified layer, cracks may be extended to the surface 11a and the back surface 11b. In this case, the workpiece 11 is separated into individual pieces in units of the device 15.

[0040] Here, the center position detection step S10 using the tape expansion device 2 will be described. In the center position detection step S10, first, the position of the center 11c in the radial direction of the workpiece 11 is detected using the holding table 4 and the laser sensor unit 8 (the first center position detection step S12).

[0041] In the first center position detection step S12, first, the surface 11a side of the workpiece 11 is sucked and held by the holding surface 4a. At this time, as shown in FIG. 2(A), the outer peripheral end portion of the workpiece 11 protrudes outside the holding surface 4a. FIG. 2(A) is a partial cross-sectional side view of the workpiece 11 etc. showing the first center position detection step S12.

[0042] After attracting and holding, while repeatedly rotating and stopping the rotating shaft 6, the coordinates of a plurality of points at three or more points on the outer peripheral edge of the workpiece 11 are acquired using the laser sensor unit 8 when it is stationary. In this way, a plurality of points on the outer peripheral edge of the workpiece 11 are detected. FIG. 2(B) is a plan view of the surface 11a side of the workpiece 11.

[0043] In this embodiment, the control unit calculates the coordinates of the center of the circumcircle of the three points 11d1, 11d2, and 11d3 on the outer peripheral edge of the workpiece 11 according to a known calculation method, thereby obtaining the coordinates of the center 11c of the front surface 11a and the back surface 11b.

[0044] After detecting the center position in the radial direction of the workpiece 11 in this way, the workpiece 11 is placed in a retracted region away from the holding table 4 once by a conveying unit (not shown) in a manner in which the relative position with respect to the center of the holding surface 4a (i.e., the origin coordinates) is grasped.

[0045] Next, an integrated tape 23 in which a circular film-like adhesive 21 is adhered to the central portion on one surface 19a of the rectangular expandable tape 19 is placed on the holding surface 4a. FIG. 3(A) is a partial cross-sectional side view of the integrated tape 23 showing the second center position detection step S14.

[0046] The expandable tape 19 has a base material layer formed of a polyolefin such as polyethylene or polypropylene, for example. However, the material of the base material layer is not limited to this example, and other suitable resin materials can also be used.

[0047] The expandable tape 19 has a substantially square shape with the size of each side being larger than the diameter of the workpiece 11. An adhesive layer is formed on one surface of the base material layer. The adhesive layer is, for example, an ultraviolet (UV) curable resin and is used to adhere a ring frame (not shown) to the integrated tape 23 after the expansion step S30 described later.

[0048] The surface of the adhesive layer corresponds to the above-described one surface 19a. A circular film-like adhesive 21 is adhered to the central portion on the one surface 19a. The film-like adhesive 21 is smoothly peeled off from the adhesive layer by subjecting the adhesive layer of the expandable tape 19 to a predetermined treatment (for example, irradiation with ultraviolet rays).

[0049] The film-like adhesive 21 contains, for example, an acrylic polymer having adhesiveness. The film-like adhesive 21 is also referred to as a Die Attach Film (DAF). The film-like adhesive 21 has a predetermined diameter that is equal to or less than the outer diameter 15c1 (see FIG. 4) of the workpiece 11 and equal to or greater than the outer diameter 15c2 (see FIG. 4) of the device region 15a.

[0050] The film-like adhesive 21 has a different light transmittance from that of the expandable tape 19 to such an extent that it can be distinguished even visually. For example, the expandable tape 19 is substantially transparent, while the film-like adhesive 21 is milky white. Therefore, the outer peripheral edge of the film-like adhesive 21 can be detected using the laser sensor unit 8.

[0051] After the first center position detection step S12, the position of the center 21c in the radial direction of the film-like adhesive 21 is detected using the holding table 4, the laser sensor unit 8, etc. (second center position detection step S14).

[0052] In the second center position detection step S14, first, as shown in FIG. 3(A), the central portion on the other surface 19b side of the expandable tape 19 is sucked and held by the holding surface 4a. At this time, by fixing the four corners of the expandable tape 19 with the above-described clamp, the integrated tape 23 is put in a stretched state (that is, a non-flexed state).

[0053] Then, while repeating the rotation and stop of the rotary shaft 6, the laser sensor unit 8 is used to acquire the coordinates of three or more points on the outer peripheral edge of the film-like adhesive 21 with the center of the holding surface 4a as the origin. In this way, a plurality of points on the outer peripheral edge of the film-like adhesive 21 are detected.

[0054] Figure 3(B) is a plan view of the integrated tape 23 in the second center position detection step S14. In the present embodiment, the control unit calculates the coordinates of the center 21c of one surface 21a of the film-shaped adhesive 21 by calculating the center of the circumscribed circle of three points 21d1, 21d2, and 21d3 on the outer peripheral edge of the film-shaped adhesive 21.

[0055] In this way, the center position in the radial direction of the film-shaped adhesive 21 is detected. In the present embodiment, the first center position detection step S12 and the second center position detection step S14 are collectively referred to as the center position detection step S10.

[0056] After the center position detection step S10, using the coordinates of the centers 11c and 21c, the one surface 21a of the film-shaped adhesive 21 is adhered to the back surface 11b of the workpiece 11 so that the centers 11c and 21c correspond (film-shaped adhesive adhesion step S20).

[0057] Figure 4 is a diagram showing the film-shaped adhesive adhesion step S20. In the film-shaped adhesive adhesion step S20, first, the workpiece 11 is turned upside down so that the back surface 11b faces downward, and the workpiece 11 is arranged on the integrated tape 23 so that the center 11c of the back surface 11b coincides with the center 21c of the one surface 21a in the XY plane direction.

[0058] Next, by lowering the workpiece 11 along the Z-axis direction, the back surface 11b side is adhered to the expand tape 19 via the film-shaped adhesive 21. At this time, the outer peripheral edge of the film-shaped adhesive 21 is located inside the outer peripheral edge of the workpiece 11 by a predetermined length 21e over the entire circumference.

[0059] Thereafter, the protective tape 17 on the surface 11a side is peeled off by a peeling unit (not shown). Thereby, a workpiece unit 25 in which the workpiece 11, the film-shaped adhesive 21, and the expand tape 19 are laminated is formed. Figure 5(A) is a top view of the workpiece unit 25, and Figure 5(B) is a cross-sectional view taken along line A-A of Figure 5(A).

[0060] Next, an expansion step S30 is performed to expand the expandable tape 19 in all directions using the expansion unit 10 (see FIG. 6). FIG. 6 is a perspective view of the expansion unit 10. In this specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other.

[0061] The expansion unit 10 includes a first clamping unit 12 and a second clamping unit 14 that expand the expandable tape 19 along the X-axis direction. The first clamping unit 12 includes a first upper clamping portion 12a that can contact one surface 19a and a first lower clamping portion 12b that can contact the other surface 19b.

[0062] A ball screw type Z-axis direction moving unit 12a1 is connected to the first upper clamping portion 12a, and a ball screw type Z-axis direction moving unit 12b1 is connected to the first lower clamping portion 12b. By operating the Z-axis direction moving units 12a1 and 12b1, the expandable tape 19 is clamped by the first upper clamping portion 12a and the first lower clamping portion 12b.

[0063] The first clamping unit 12 is provided with a ball screw type X-axis direction moving unit 12c that moves each of the Z-axis direction moving units 12a1, 12a2, the first upper clamping portion 12a, and the first lower clamping portion 12b along the X-axis direction.

[0064] A plurality of columnar roller portions 12d (not shown) whose height directions are arranged along the X-axis direction are provided side by side in the Y-axis direction on the bottom side of the first upper clamping portion 12a. Similarly, a plurality of roller portions 12d are provided on the top side of the first lower clamping portion 12b.

[0065] Each roller portion 12d can contact the expandable tape 19 and is configured to be rotatable around a rotation axis along the X-axis direction. Therefore, even when the expandable tape 19 is pulled in the X-axis direction by the first clamping unit 12, the expandable tape 19 can expand in the Y-axis direction.

[0066] The second clamping unit 14 also has substantially the same structure as the first clamping unit 12. The second clamping unit 14 has a second upper clamping portion 14a that can contact one surface 19a and a second lower clamping portion 14b that can contact the other surface 19b.

[0067] A ball screw type Z-axis direction moving unit 14a1 is provided on the second upper clamping portion 14a, and a ball screw type Z-axis direction moving unit 14b1 is provided on the second lower clamping portion 14b. The second upper clamping portion 14a and the second lower clamping portion 14b move along the X-axis direction by a ball screw type X-axis direction moving unit 14c.

[0068] On each of the bottom side of the second upper clamping portion 14a and the top side of the second lower clamping portion 14b, a plurality of columnar roller portions 14d whose height directions are arranged along the X-axis direction are provided. Each roller portion 14d can contact the expandable tape 19 and is configured to be rotatable around a rotation axis along the X-axis direction.

[0069] Further, the expansion unit 10 has a third clamping unit 16 and a fourth clamping unit 18 that expand the expandable tape 19 along the Y-axis direction. The third clamping unit 16 and the fourth clamping unit 18 also have a structure similar to that of the first clamping unit 12.

[0070] A ball screw type Z-axis direction moving unit 16a1 is provided on the third upper clamping portion 16a, and a ball screw type Z-axis direction moving unit 16b1 is provided on the third lower clamping portion 16b. The third upper clamping portion 16a and the third lower clamping portion 16b move along the Y-axis direction by a ball screw type Y-axis direction moving unit 16c.

[0071] On each of the bottom side of the third upper clamping portion 16a and the top side of the third lower clamping portion 16b, a plurality of columnar roller portions 16d whose height directions are arranged along the Y-axis direction are provided. Each roller portion 16d can contact the expandable tape 19 and is configured to be rotatable around a rotation axis along the Y-axis direction.

[0072] The fourth upper clamping part 18a is provided with a ball screw type Z-axis direction moving unit 18a1, and the fourth lower clamping part 18b is provided with a ball screw type Z-axis direction moving unit 18b1. The fourth upper clamping part 18a and the fourth lower clamping part 18b move along the Y-axis direction by a ball screw type Y-axis direction moving unit 18c.

[0073] On each of the bottom side of the fourth upper clamping part 18a and the top side of the fourth lower clamping part 18b, a plurality of columnar roller parts 18d whose height directions are arranged along the Y-axis direction are provided. Each roller part 18d can contact the expand tape 19 and is configured to be rotatable around a rotation axis along the Y-axis direction.

[0074] With the expand tape 19 being clamped by the third upper clamping part 16a and the third lower clamping part 16b, and the fourth upper clamping part 18a and the fourth lower clamping part 18b, when the Y-axis direction moving units 16c, 18c are operated so that the third clamping unit 16 and the fourth clamping unit 18 move away from each other, the expand tape 19 is expanded in the Y-axis direction.

[0075] Since each roller part 16d, 18d is configured to be rotatable around a rotation axis along the Y-axis direction, even when the expand tape 19 is in a state of being pulled in the Y-axis direction, the expand tape 19 can be expanded in the X-axis direction.

[0076] In the vicinity of the expansion unit 10, a cooling air supply pipe (not shown) connected to a cooler unit (not shown) is arranged. From the cooling air supply pipe, air cooled to a temperature of, for example, -10°C or higher and 0°C or lower is jetted. The film-like adhesive 21 is cooled by this air.

[0077] In the expansion step S30, the holding table 4 is raised, and after the expand tape 19 is clamped by the first clamping unit 12 to the fourth clamping unit 18 respectively, the negative pressure and the clamp of the holding table 4 are released. Then, the holding table 4 retracts downward.

[0078] While moving the holding table 4, cooled air is jetted from the cooling air supply pipe to the workpiece unit 25. Thereby, the film-like adhesive 21 is cooled to reduce the stretchability of the film-like adhesive 21.

[0079] Thereafter, the first holding unit 12 and the second holding unit 14 are moved so as to be separated from each other in the X-axis direction, and the third holding unit 16 and the fourth holding unit 18 are moved so as to be separated from each other in the Y-axis direction.

[0080] Thereby, the expand tape 19 is expanded by, for example, about 20 mm in each of the X-axis direction and the Y-axis direction. FIG. 7(A) is a top view of the workpiece unit 25 showing the expansion step S30, and FIG. 7(B) is a partial cross-sectional side view of FIG. 7(A).

[0081] Although the workpiece 11 before the expansion step S30 has a modified layer, it is not singulated into individual device units 15. In the expansion step S30, the workpiece 11 receives external forces along the X-axis direction and the Y-axis direction from the expand tape 19 that is expanded in the X-axis direction and the Y-axis direction.

[0082] Thereby, the workpiece 11 is singulated into a plurality of device chips 27, and the film-like adhesive 21 is broken along each division planned line 13 (see FIGS. 8(A) and 8(B)).

[0083] FIG. 8(A) is a top view of the workpiece unit 25 after the expansion step S30, and FIG. 8(B) is a partial cross-sectional side view of FIG. 8(A). In the expansion step S30, a gap having the same size as the gap 11e formed between the device chips 27 is also formed in the film-like adhesive 21.

[0084] In addition, when the workpiece 11 before the expansion step S30 is singulated into device chips 27 in units of devices 15, in the expansion step S30, the intervals between the already singulated device chips 27 are expanded. Thereby, it becomes easy to pick up the device chips 27.

[0085] In the expansion step S30, since the outer peripheral edge of the film-like adhesive 21 is located inside the outer peripheral edge of the workpiece 11, the small piece 21b (see FIG. 8(A)) of the film-like adhesive 21 is pressed by the end material chip. Therefore, the scattering of the small piece 21b can be suppressed.

[0086] Next, a comparative example in which the small piece 21b scatters will be described. FIG. 9(A) is a top view of the workpiece unit 25 showing the expansion step S30 in the comparative example, and FIG. 9(B) is a top view of the workpiece unit 25 after the expansion step S30 in the comparative example.

[0087] In FIG. 9(B), for the sake of convenience, the size of the small piece 21b is exaggerated, but the actual size of the small piece 21b may be smaller than the size of the small piece 21b shown in FIG. 9(B). Also, the number of the small pieces 21b that scatter is not limited to the four shown in FIG. 9(B).

[0088] The diameter of the film-like adhesive 21 in the comparative example is larger than the outer diameter 15c1 of the workpiece 11. Therefore, when the back surface 11b is adhered to the one surface 21a so that the center 11c in the radial direction of the workpiece 11 and the center 21c in the radial direction of the film-like adhesive 21 coincide, the outer peripheral edge of the film-like adhesive 21 protrudes from the outer peripheral edge of the workpiece 11 over the entire circumference.

[0089] As a result, when the film-like adhesive 21 is broken along each division planned line 13 in the expansion step S30, as shown in FIG. 9(B), the small pieces 21b of the film-like adhesive 21 may scatter. In contrast, in the above-described first embodiment, the scattering of the small piece 21b can be suppressed.

[0090] Next, a second embodiment will be described with reference to FIGS. 10(A) and 10(B). In the center position detection step S10 of the second embodiment, instead of the laser sensor unit 8, an optical camera 20 is used.

[0091] The optical camera 20 includes a condenser lens, an imaging device such as a CCD (not shown). The imaging device is connected to the control unit, and the control unit processes the image acquired by the optical camera 20 according to a program for performing predetermined image processing stored in the auxiliary storage device.

[0092] In the first center position detection step S12 of the second embodiment, the optical camera 20 acquires an image of a part of the outer peripheral portion of the back surface 11b. Then, the control unit performs image processing on the acquired image to obtain the XY coordinates of one point corresponding to the edge of the workpiece 11. In this way, the coordinates of three points on the outer peripheral edge of the workpiece 11 are obtained.

[0093] Next, the control unit calculates the coordinates of the center 11c based on the coordinates of the three points to detect the center position in the radial direction of the workpiece 11. FIG. 10(A) is a diagram showing the first center position detection step S12 according to the second embodiment.

[0094] Next, in the second center position detection step S14 of the second embodiment, the optical camera 20 acquires an image of a part of the outer peripheral portion of one surface 21a of the film-like adhesive 21. Then, the control unit performs image processing on the acquired image to obtain the XY coordinates of one point corresponding to the edge of the film-like adhesive 21. In this way, the coordinates of three points on the outer peripheral edge of the film-like adhesive 21 are obtained.

[0095] Next, the control unit calculates the coordinates of the center 21c based on the coordinates of the three points to detect the center position in the radial direction of the film-like adhesive 21. FIG. 10(B) is a diagram showing the second center position detection step S14 according to the second embodiment.

[0096] In this way, in the second embodiment, the difference from the first embodiment is that the center position detection step S10 is performed using the optical camera 20, but other points are the same as those in the first embodiment. Also in the second embodiment, the scattering of the small pieces 21b of the film-like adhesive 21 can be suppressed.

[0097] In addition, the structures, methods, etc. according to the above-described embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention. In the above-described center position detection step S10, the holding table 4 having the holding surface 4a with a diameter smaller than the diameter of the workpiece 11 was used.

[0098] However, instead of this holding table 4, a holding table (not shown) having a circular or rectangular transparent plate having a size larger than that of the expandable tape 19 may be used. In this case, the above-described arm portion, clamp, etc. are omitted.

[0099] The transparent plate is formed of a material that is transmissive to visible light such as glass or quartz. Further, the transparent plate is formed with suction ports (not shown) for sucking the workpiece 11, the protective tape 17, the expandable tape 19, etc. A suction source (not shown) such as an ejector is connected to the suction port.

[0100] When performing the center position detection step S10 and the film-like adhesive sticking step S20 using the holding table having the transparent plate, the laser beam L is irradiated from the light source unit 8a to the light receiving unit 8b through the transparent plate.

[0101] After the center position detection step S10 and the film-like adhesive sticking step S20, a conveyance unit (not shown) sucks and holds four locations of the expandable tape 19 and conveys the workpiece unit 25 to the expansion unit 10. Thereafter, the expansion step S30 is performed.

Explanation of Reference Numerals

[0102] 2: Tape expansion device, 4: Holding table, 4a: Holding surface, 6: Rotating shaft 8: Laser sensor unit, 8a: Light source unit 8a1: Laser diode, 8a2: Fixed mirror, 8b: Light receiving unit, 8b1: Light receiving element 10: Expansion unit 11: Workpiece, 11a: Surface, 11b: Back surface, 11c: Center 11d1, 11d2, 11d3: Points, 11e: Gap 12: First clamping unit, 12a: First upper clamping part, 12b: First lower clamping part 12a1, 12b1, 14a1, 14b1: Z-axis direction moving unit 12c, 14c: X-axis direction moving unit, 12d, 14d: Roller part 13: Scheduled dividing line, 15: Device, 15a: Device area, 15b: Outer peripheral surplus area 15c1, 15c2: Outer diameter, 17: Protective tape 14: Second clamping unit, 14a: Second upper clamping part, 14b: Second lower clamping part 16: Third clamping unit, 16a: Third upper clamping part, 16b: Third lower clamping part 16a1, 16b1, 18a1, 18b1: Z-axis direction moving unit 16c, 18c: Y-axis direction moving unit, 16d, 18d: Roller part 18: Fourth clamping unit, 18a: Fourth upper clamping part, 18b: Fourth lower clamping part 19: Expandable tape, 19a: One side, 19b: The other side 20: Optical camera 21: Film-shaped adhesive, 21a: One side, 21b: Small piece, 21c: Center 21d1, 21d2, 21d3: Points, 21e: Predetermined length 23: Integrated tape, 25: Workpiece unit, 27: Device chip L: Laser beam

Claims

【Claim 1】 A tape expansion method in which a tape having a size larger than that of a workpiece is adhered via a film-like adhesive to the back side of a disk-shaped workpiece having on the front side a device region in which devices are provided in each of a plurality of regions partitioned by a plurality of division planned lines set in a grid pattern, and an outer peripheral surplus region surrounding the device region, the method comprising: a center position detection step of detecting a radial center position of the circular film-like adhesive having a diameter equal to or less than the outer diameter of the workpiece and equal to or greater than the outer diameter of the device region, and a radial center position of the workpiece; a film-like adhesive attaching step of attaching the film-like adhesive to the back side of the workpiece such that the radial center position of the film-like adhesive corresponds to the center position of the back side, using the detected center positions after the center position detection step; an expansion step of fragmenting the workpiece into a plurality of device chips or expanding the intervals between the plurality of already fragmented device chips by expanding the tape, and breaking the film-like adhesive along the plurality of division planned lines; and the center position detection step is characterized in that a laser sensor unit having a laser oscillator that emits a laser beam and a light receiving element that receives the laser beam is used to detect three or more points on the outer peripheral edge of the film-like adhesive and three or more points on the outer peripheral edge of the workpiece, calculate the radial center position of the film-like adhesive from the detected three or more points on the outer peripheral edge of the film-like adhesive, and calculate the radial center position of the workpiece from the detected three or more points on the outer peripheral edge of the workpiece.

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