JP2012146722A - Method of applying external force to workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable segmentation by expansion of an adhesive tape also in a workpiece with high strength, by effectively applying stress to the workpiece which is attached to the flexible adhesive tape and has high strength.SOLUTION: This external force application method includes: a holding process of holding a workpiece unit 4 by holding a frame 1 of the workpiece unit 4 having a configuration in which a workpiece 3 is held via an expansion tape 2 attached to close an opening part 10 of the frame 1: and an external force application process of expanding the expansion tape 2 by relatively displacing the workpiece 3 with respect to the frame 1 in a direction vertical to the surface of the workpiece 3 to apply external force to the workpiece 3. By executing a cooling process of cooling at least a portion 20 of the expansion tape 2 between an inner periphery of the frame 1 and an outer periphery of the workpiece 3 before the external force application process, the expansion tape 2 between the inner periphery of the frame 1 and the outer periphery of the workpiece 3 is hardened. Thus, even when the strength of the workpiece 3 is high, stress is effectively applied to the workpiece 3 in the external force application process.

Description

  The present invention relates to a method for applying an external force to a work by expanding an adhesive tape attached to the work.

  As a method of dividing various workpieces along the planned dividing line, the workpiece is attached to the adhesive tape, and after forming the modified layer by condensing the laser beam inside the workpiece along the scheduled dividing line, the adhesive tape There has been proposed a method in which the modified layer is broken by applying a stress to the line to be divided by extending in the surface direction of the workpiece. Moreover, even when not using a laser beam, it may break along the division | segmentation planned line by applying external force to the adhesive tape stuck to the workpiece | work (for example, refer patent document 1).

JP 2010-263164 A

  However, in order to divide a workpiece with high strength such as metal by expanding the adhesive tape, it is necessary to apply a strong stress to the line where the workpiece is scheduled to be divided. Of the tape, there is a problem that only a portion where the workpiece is not attached, that is, a portion between the inner periphery of the frame and the outer periphery of the workpiece expands, and it is difficult to apply stress to the division line.

  On the other hand, when a relatively hard adhesive tape having a high Young's modulus is used, a problem may occur in other processes. For example, in a pick-up process in which a chip is peeled off from an adhesive tape and picked up, the adhesive tape needs to be stretched to some extent, so that flexibility is required.

  The present invention has been made in view of such problems, and the purpose of the present invention is to effectively apply stress to a high-strength work affixed to a flexible adhesive tape, thereby providing a high-strength work. It is also possible to divide by expanding the adhesive tape.

  The present invention relates to a holding step of holding a work unit by holding a frame of a work unit including a frame having an opening and a work held in the opening via an expansion tape, and the work to the frame. An external force applying method that includes expanding an expansion tape by moving the tape in a direction perpendicular to the surface of the tape and applying an external force to the workpiece, and before the external force applying step, at least of the expansion tape A cooling process is performed to cool a corresponding portion between the inner periphery of the frame and the outer periphery of the workpiece.

  In the cooling process, it is desirable to cool the entire expansion tape.

  In the present invention, before the external force applying step, at least a portion of the expansion tape between the inner periphery of the frame and the outer periphery of the work is cooled. The expansion tape can be cured. Therefore, even when the strength of the workpiece is high, stress can be effectively applied to the workpiece in the external force applying step, and the division by the external force applying step can be performed smoothly without affecting other steps.

  Also, in the cooling process, by cooling the entire expansion tape, the hardness of the entire expansion tape is increased, and the portion of the adhesive tape that is attached to the broken split line is difficult to stretch. Stress is easily applied to the planned division line that is not broken, and the division can be performed more smoothly.

(A) is a perspective view which shows the work unit of the structure by which the work was supported by the flame | frame via the expansion tape, (B) is sectional drawing which shows a work unit schematically. It is sectional drawing which shows schematically the state which forms a modification layer in a workpiece | work. It is a disassembled perspective view which shows a tape expansion apparatus. It is a perspective view which shows the external appearance of a tape expansion apparatus. It is sectional drawing which shows this invention roughly according to a process, (A) is the state which mounted the frame in the frame support part, (B) is the state which clamped the frame with the frame support part and the frame holding | suppressing part, C) shows a state where the non-sticking part of the expansion tape is cooled, and (D) shows a state where the tape is expanded. It is sectional drawing which shows schematically the state which cools the whole expansion tape.

(1) Processing Step The frame 1 shown in FIGS. 1 (A) and 1 (B) is formed in an annular shape having an opening 10 at the center, and is formed of a polymer material on the back surface 11 of the frame 1 and can be expanded and contracted. An expansion tape 2 is attached. The opening 10 formed in the frame 1 is closed by the expansion tape 2, and the back surface 30 of the work 3 is adhered to the expansion tape 2 in the opening 10. The back surface 30 is a metal film. In this way, the work 3 is held integrally with the frame 1 via the expansion tape 2, and the work unit 4 is configured as a whole.

  The workpiece 3 is not particularly limited. For example, a semiconductor wafer such as a silicon wafer, gallium arsenide, or silicon carbide, an adhesive member such as DAF (Die Attach Film) provided on the back surface of the wafer for chip mounting, a semiconductor product package, Examples include ceramics, glass, sapphire-based inorganic material substrates, various electronic parts such as liquid crystal display drivers, and various processing materials that require micron-order processing position accuracy. Moreover, although not shown in figure, the division | segmentation scheduled line is set to the surface 31 of the workpiece | work 3, and it can divide | segment into each chip | tip by fracture | rupturing along a division | segmentation scheduled line.

  In the work unit 4, a portion between the inner periphery 12 of the frame 1 and the outer periphery 32 of the work 3 in the expansion tape 2 is a portion where the frame 1 and the work 3 are not attached. Composed. Further, on the inner peripheral side of the non-sticking part 20, a work sticking part 21 that is a part of the expansion tape 2 to which the work 3 is stuck is configured.

  For example, as shown in FIG. 2, the work unit 4 is held on a holding table 50 of the laser processing apparatus 5. Then, the laser irradiation unit 51 of the laser processing apparatus 5 and the holding table 50 are relatively moved in the horizontal direction, the laser beam 51a is emitted from the laser irradiation unit 51, and is condensed inside the workpiece 3 along the planned division line. By doing so, the modified layer 33 is formed along all the division lines. The modified layer 33 refers to a region where the density, refractive index, mechanical strength, and other physical characteristics are different from the surroundings. For example, there are (a) a melt treatment region, (b) a crack region, a dielectric breakdown region, (c) a refractive index change region, and there are also regions where these are mixed.

  In the machining process, a method other than laser machining can be used. For example, by cutting the cutting blade from the front surface 31 side of the work 3 along the planned dividing line, the work 3 is imperfectly formed on the back surface 30 side. You may cut so that a cutting part may remain.

(2) Holding Step The tape expanding device 6 shown in FIG. 3 is held by the holding unit 60 that holds the work unit 4, the frame pressing portion 61 that holds the frame 1 between the holding unit 60, and the holding unit 60. The expansion unit 2 includes a cooling unit 62 that cools the expansion tape 2 and a lid member 63 that covers the cooling unit 62 from above.

  As shown in FIG. 3, the holding unit 60 is formed in a cylindrical shape and supports a workpiece 3 from below and can be moved up and down, and a support surface 601 a disposed on the outer peripheral side of the workpiece support 600. A frame support unit 601 that supports the frame 1 from below, a workpiece lifting / lowering unit 602 that lifts and lowers the workpiece 3 held by the workpiece support unit 600 by moving the workpiece support unit 600 up and down, and a frame lifting and lowering unit that lifts and lowers the frame support unit 601 Means 603. In the holding step, since the work unit 4 is held by the tape expansion device 6 by holding the frame 1 between the holding unit 60 and the frame pressing portion 61, the holding unit 64 and the frame pressing portion 61 hold the holding means 64. Is configured.

  As shown in FIG. 3, the cooling means 62 includes a circular base 620, a shaft part 621 that is connected to the center of the base 620 and can rotate together with the base 620, and cool air is jetted downward from the periphery of the base 620. And an action part 622 for cooling the expansion tape 2. On the other hand, the frame pressing portion 61 is formed with a through hole 610 through which the cooling means 62 is inserted in the vertical direction.

  The outer diameter of the work support portion 600 is formed smaller than the inner diameter of the frame support portion 601 and the frame pressing portion 602, and between the outer periphery of the work support portion 600 and the inner periphery of the frame support portion 601 and the frame pressing portion 602. A gap is formed.

  The frame lifting / lowering means 603 is composed of at least three (four in the illustrated example) air cylinders, and is composed of a cylinder tube 603a and a piston rod 603b. The upper end of the piston rod 603b is fixed to the lower surface of the frame support portion 601, and the frame support portion 601 is raised and lowered by raising and lowering the piston rod 603b.

  The holding unit 60 shown in FIG. 3 is accommodated in a housing 65 as shown in FIG. An opening / closing door 650 is provided on the side surface of the housing 65. When the opening / closing door 650 is opened, the work unit 4 shown in FIG. 1 can be carried in and out of the housing 65. Further, the cooling means 62 shown in FIG. 3 is accommodated inside the lid member 63.

  In the holding step, as shown in FIG. 5A, first, the frame 1 is placed on the support surface 601a of the frame support portion 601. Then, by raising the frame support portion 601 under the control of the frame elevating means 602, the frame 3 is held between the frame support portion 601 and the frame pressing portion 61 as shown in FIG. 4 is held in the holding unit 60. At this time, the non-sticking part 20 of the expansion tape 2 is located below the action part 622 of the cooling means 62. Further, the upper end of the workpiece support unit 600 is located at a position lower than the support surface 601a of the frame support unit 601.

(3) Cooling Step Next, as shown in FIG. 5C, the cooling means 62 is lowered, and the action portion 622 is at least the inner periphery 12 of the frame 1 of the non-sticking portion 20, that is, the expansion tape 2. A portion corresponding to the outer periphery 32 of the work 3 is cooled. Then, since the expansion tape 2 is formed of a polymer material, it is cured by cooling. The expansion tape 2 is preferably cooled to 10 to -15 ° C, more preferably 5 to -5 ° C.

(4) External force application process Next, the work lifting means 602 raises the work support section 600 as shown in FIG. 5D in a state where the frame 3 is sandwiched between the frame support section 601 and the frame pressing section 61. . Then, the workpiece 3 moves relative to the frame 1 in a direction perpendicular to the surface 31 of the workpiece 3, and the expansion tape 2 is radially expanded in the plane direction around the center of the opening 10. In this way, the work lifting / lowering means 602 functions as an expansion means for expanding the expansion tape 2.

  When the expansion tape 2 is expanded in the surface direction in this way, an external force in the surface direction is also applied to the work 3 adhered to the expansion tape 2, and the external force is transmitted to the modified layer 33 shown in FIG. Then, the workpiece W is broken along the division line and divided into individual chips 34. In addition, even after being divided into the chips 34, by further raising the work support portion 600, the interval between the plurality of chips can be extended to a desired distance.

  Before the external force imparting step, since at least the non-sticking portion 20 of the expansion tape 2 is cooled and cured in the cooling step, when the expansion tape 2 is expanded, the workpiece sticking portion 21 to which the workpiece 3 is stuck is: It is harder to stretch than the non-sticking part 20. Therefore, stress can be effectively applied to the modified layer 33, and even when the work 3 has high strength, the expansion tape 2 can be divided by expansion.

  In the cooling process, the non-sticking portion 20 of the expansion tape 2 is cooled. However, the entire expansion tape 2 may be cooled to increase the overall hardness. In this case, for example, as shown in FIG. 6, the tape expansion device 6 is accommodated in a sealed box body 66. Then, a cool air introduction portion 67 for sending cool air into the box body 66 is connected to the box body 66. In the cooling step, the entire expansion tape 2 is cooled by feeding cool air in the direction of arrow A from the cool air introduction portion 67 toward the box body 66 and cooling the inside of the box body 66. Then, the work 3 is divided into individual chips 34 by performing an external force applying step.

  After the entire expansion tape 2 is cooled in the cooling process, if the expansion tape 2 of the work unit 4 accommodated in the box 65 is extended in the surface direction in the external force applying process, the entire hardness of the expansion tape 2 is increased. Therefore, in addition to the fact that the non-sticking portion 20 is difficult to stretch, the portion of the expansion tape 2 that is stuck to the broken split line is also difficult to stretch. Stress is easily applied to the planned line, and division can be performed more smoothly.

DESCRIPTION OF SYMBOLS 1: Frame 10: Opening part 11: Back surface 12: Inner circumference 2: Expansion tape 20: Non-sticking part 21: Work sticking part 3: Work 30: Back side 31: Front surface 32: Outer part 33: Modified layer 34: Chip 4: Work unit 5: Laser processing device 50: Holding table 51: Laser irradiation unit 51a: Laser beam 6: Tape expansion device 60: Holding unit 600: Work support unit 601: Frame support unit 602: Work lift unit 603: Frame lift Means 603a: Cylinder tube 603b: Piston rod 61: Frame pressing part 610: Through hole 62: Cooling means 620: Base 621: Shaft part 622: Action part 63: Lid member 64: Holding means 65: Housing 650: Opening / closing door 66 : Box 67: Cold air introduction part

Claims (2)

A holding step of holding the work unit by holding the frame of a work unit comprising a frame having an opening and a work held in the opening via an expansion tape;
An external force applying step of applying an external force to the work by expanding the expansion tape by moving the work relative to the frame in a direction perpendicular to the surface of the work;
An external force applying method including:
An external force applying method for performing a cooling step of cooling at least a portion of the expansion tape between the inner periphery of the frame and the outer periphery of the work before the external force applying step. 2. The external force applying method according to claim 1, wherein the entire expansion tape is cooled in the cooling step.

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