Work division device

Abstract

To provide a work division device that can simultaneously solve a problem of non-division along a division line that occurs when the chip size is small, and a problem of reduced chip quality caused by contact between chips after division.SOLUTION: In a work division device (10), an expanding ring arranged on the back side of a dicing tape opposite a work attachment surface presses an annular region of the dicing tape that is more inward than the inner edge of a frame, expanding the dicing tape, and an expansion control ring (16) arranged on the same side of the dicing tape as the work attachment surface is abutted at a position in the annular region that is more outer than the pressing position of the expanding ring, thereby restricting the expansion of the outer peripheral region of the annular region that is located on the outer side of the abutment portion abutted by the expansion control ring.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a work dividing device and a work dividing method, and more particularly to a work dividing device and a work dividing method for dividing a work such as a semiconductor wafer into individual chips along planned division lines. [Background technology]

[0002] Conventionally, in the manufacture of semiconductor chips (hereinafter referred to as chips), a work division device has been known which divides a semiconductor wafer (hereinafter referred to as wafer), into which a division line has been formed in advance by half-cutting with a dicing blade or by forming a modified region by laser irradiation, into individual chips along the division line (see Patent Document 1, etc.).

[0003] FIG. 12 is an explanatory diagram of a wafer unit 2 to which a disk-shaped wafer 1 to be divided by a work dividing device is attached, FIG. 12(A) is an oblique view of the wafer unit 2, and FIG. 12(B) is a vertical cross-sectional view of the wafer unit 2.

[0004] The wafer 1 is attached to the center of a dicing tape (also called an expansion tape or adhesive sheet) 3 that is approximately 100 μm thick and has an adhesive layer formed on one side, and the dicing tape 3 is fixed at its outer periphery to a rigid ring-shaped frame 4.

[0005] In the workpiece dividing device, the frame 4 of the wafer unit 2 is fixed by contacting it with a frame fixing member (also called a frame fixing mechanism) 7 shown by a two-dot chain line. After this, an expand ring (also called a push-up ring) 8 shown by a two-dot chain line is moved upward from below the wafer unit 2, and the dicing tape 3 is pressed by this expand ring 8 to expand radially. The tension of the dicing tape 3 generated at this time is applied to the division lines 5 of the wafer 1, so that the wafer 1 is divided into individual chips 6. The division lines 5 are formed in the X direction and the Y direction which are perpendicular to each other. Regarding the division lines 5, when the number of lines parallel to the X direction and the number of lines parallel to the Y direction are the same and the intervals in each direction are equal, the shape of the divided chips 6 is a square. When the number of lines parallel to the X direction and the number of lines parallel to the Y direction are different and the intervals in each direction are equal, the shape of the divided chips 6 is a rectangle.

[0006] Incidentally, the dicing tape 3 is a flexible material with a low Young's modulus. Therefore, in order to smoothly divide the wafer 1 into individual chips 6, it is conceivable to expand the dicing tape 3 by cooling the dicing tape 3 and increasing its spring constant.

[0007] The tape expanding device (workpiece dividing device) of Patent Document 2 is equipped with a cold air supplying means. According to Patent Document 2, the cold air supplying means is operated to supply cold air into the processing space, and the processing space is cooled to, for example, 0°C or less, thereby cooling the dicing tape.

[0008] Meanwhile, the chip separation device (workpiece dividing device) of Patent Document 3 focuses on the anisotropy of the dicing tape and is equipped with a film surface support mechanism to uniformly expand the dicing tape while taking this anisotropy into account. This film surface support mechanism is equipped with multiple support mechanisms that are independent in the circumferential direction, and the relative heights of the multiple support mechanisms are individually controlled to adjust the tension of the dicing tape, thereby independently controlling the elongation of the dicing tape in the X and Y directions.

[0009] In this specification, the area of ​​the dicing tape 3 that is circular in plan view to which the wafer 1 is attached is referred to as the central area 3A, the area that is doughnut-shaped in plan view provided between the outer edge of the central area 3A (the outer edge of the wafer 1) and the inner edge of the frame 4 is referred to as the annular area 3B, and the area that is doughnut-shaped in plan view at the outermost periphery that is fixed to the frame 4 is referred to as the fixed area 3C. The annular area 3B is the area that is expanded by being pressed by the expand ring 8.

[0010] It is known that the force required to divide the wafer 1, i.e., the tension that must be generated in the annular region 3B to divide the wafer 1, must be higher as the number of dividing lines 5 increases. Regarding the number of dividing lines 5, for example, when the wafer 1 has a diameter of 300 mm and the chip size is 5 mm, about 120 dividing lines 5 (60 in each of the X and Y directions) are formed, and when the chip size is 1 mm, about 600 dividing lines 5 are formed. Therefore, the tension that must be generated in the annular region 3B must be higher as the chip size becomes smaller.

[0011] On the other hand, in the field of workpiece dividing devices, it is also required to prevent deterioration of chip quality due to contact between chips after division by maintaining the expanded state of the dicing tape expanded by the expanding ring.

[0012] As a work division device that satisfies this requirement, a work division device equipped with a sub-ring is disclosed in Patent Document 4. The sub-ring of Patent Document 4 has a function of holding the dicing tape expanded by the expanding ring in an expanded state, and is configured to have a diameter larger than the inner diameter of the frame. The sub-ring is inserted between the outer periphery of the dicing tape and the surface of the frame immediately after it is raised from the back side of the dicing tape toward the dicing tape and passes through the frame. This maintains the expanded state of the dicing tape even after the expansion of the dicing tape by the expanding ring is completed. By maintaining the expanded state of the dicing tape in this way, it is possible to prevent the dicing tape from loosening, thereby preventing the quality degradation of the chips caused by contact between the chips. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] JP 2016-149581 A [Patent Document 2] JP 2016-12585 A [Patent Document 3] Patent No. 5912274 [Patent Document 4] JP 2013-51368 A Summary of the Invention [Problem to be solved by the invention]

[0014] Incidentally, the inner diameter (diameter of the inner edge of the frame) of the frame 4 on which the wafer 1 with a diameter of 300 mm is mounted is set to 350 mm according to the SEMI standard (G74-0699 Specifications for Tape Frames for 300 mm Wafers). According to this standard, as shown in the longitudinal section of the wafer unit 2 in FIG. 13, an annular region 3B having a width dimension of 25 mm exists between the outer edge of the wafer 1 and the inner edge of the frame 4. Also, as shown in the longitudinal section of the essential part of the workpiece dividing device shown in FIGS. 14(A) and 14(B), the frame fixing member 7 for fixing the frame 4 is installed at a position spaced outward from the annular region 3B in the in-plane direction of the dicing tape 3 indicated by the arrow A so as not to come into contact with the annular region 3B expanded by the expand ring 8.

[0015] Therefore, the force dividing the wafer 1 generated by the rising movement of the expand ring 8 is decomposed into three forces: (i) a force to expand the entire area of ​​the annular region 3B, (ii) a force to divide the wafer 1 into chips 6, and (iii) a force to expand the dicing tape 3 between adjacent chips 6.

[0016] As shown in the operation diagram of the workpiece dividing device in Figures 15(A) to (E), when the expand ring 8 comes into contact with the annular region 3B of the dicing tape 3 and the dicing tape 3 starts to expand due to the rising movement of the expand ring 8 (Figure 15(A)), the annular region 3B, which has the lowest spring constant, starts to expand first (Figure 15(B)). As a result, tension is generated in the annular region 3B, and when this tension increases to a certain level, the increased tension is transmitted to the wafer 1, and the division of the wafer 1 into chips 6 begins (Figure 15(C)). When the wafer 1 is divided into individual chips 6, the expansion of the annular region 3B and the expansion of the dicing tape 3 between the chips proceed simultaneously (Figures 15(D) to (E)).

[0017] In the conventional workpiece dividing device, when the chip size of a wafer 1 having a diameter of 300 mm is 5 mm or more, the wafer 1 can be divided into individual chips 6 without any problem by the tension generated in the annular region 3B. However, as the circuit patterns formed on the wafer 1 become finer, chips having a smaller chip size of 1 mm or less have appeared. In this case, the force required to divide the wafer 1 increases due to an increase in the number of division lines 5 for dividing the wafer 1, and a force greater than the tension caused by the expansion of the annular region 3B may be required. As a result, as shown in the vertical cross-sectional view of the wafer unit 2 in FIG. 16, a problem occurs in that even after the expansion operation by the expand ring 8 is completed, some of the division lines 5 formed on the wafer 1 remain undivided.

[0018] Such a problem of the division lines 5 not being divided cannot be solved even if the expansion amount or expansion speed of the dicing tape 3 is increased. For example, if the expansion amount of the dicing tape 3 is increased, the annular region 3B starts to undergo plastic deformation. Since the spring constant of the annular region 3B during plastic deformation is smaller than the spring constant during elastic deformation, no tension is generated to divide the wafer 1 into individual chips 6 in the region of the annular region 3B that exceeds the elastic deformation. On the other hand, even if the expansion speed of the dicing tape 3 is increased, a part of the annular region 3B starts to undergo plastic deformation, so no tension is generated to divide the wafer 1 into individual chips 6. This is because the frequency response of the dicing tape 3 is low, and therefore the force is not transmitted to the entire dicing tape 3 without time lag.

[0019] In order to solve the problem of non-division of the intended division lines 5, Patent Document 2 addresses this by cooling the dicing tape and increasing the spring constant of the dicing tape, but this is not sufficiently effective for recent small chips of 1 mm or less.

[0020] Furthermore, the chip separation device of Patent Document 3 can independently control the elongation of the dicing tape in the X and Y directions, but cannot apply to the wafer a force greater than the tension caused by the expansion of the annular region, and therefore cannot solve the problem of non-division along the intended division lines.

[0021] Furthermore, the work division devices of Patent Documents 1 to 3 do not include a sub-ring as in Patent Document 4, and therefore may cause a problem of deterioration in chip quality due to contact between chips after division. As described above, there is no conventional work division device that can solve the problem of non-division along the division line that occurs when the chip size is small, while also solving the problem of deterioration in chip quality due to contact between chips after division, and there has been a demand for the realization of such a device.

[0022] The present invention has been made in consideration of such problems, and aims to provide a work division device and a work division method that can simultaneously solve the problem of non-division of the planned division line that occurs when the chip size is small, and the problem of reduced chip quality due to contact between chips after division. [Means for solving the problem]

[0023] In order to achieve the object of the present invention, the work division device of the present invention has an outer periphery of a dicing tape fixed to a ring-shaped frame having an inner diameter larger than the outer diameter of the work, and divides the work attached to the dicing tape into individual chips along a planned division line, the work division device comprising: an expanding ring arranged on the back side of the dicing tape opposite the surface on which the work is attached, the expanding ring having an opening smaller than the inner diameter of the frame and larger than the outer diameter of the work, the expanding ring being moved in a direction approaching the dicing tape relatively to press and expand the dicing tape; the expansion restriction ring is formed in a ring shape having a recess, the expansion restriction ring being brought into contact with the dicing tape when the dicing tape is expanded, and restricting the expansion of an outer circumferential region of the dicing tape located on the outer circumferential side of the contact portion of the dicing tape that abuts against the expansion restriction ring; an expansion restriction ring moving mechanism that moves the expansion restriction ring away from the position where it restricts the expansion of the outer circumferential region; and an expansion retaining ring that is formed in a ring shape and has an elastically deformable fitting portion that is larger than the inner diameter of the frame, and that maintains the expanded state of the dicing tape by having the fitting portion fit into the surface of the frame after the expansion restriction ring is moved away from the position where it restricts the expansion of the outer circumferential region by the expansion restriction ring moving mechanism.

[0024] According to the workpiece dividing device of the present invention, when the expanding ring is moved in a direction approaching the dicing tape relatively in a state where the expansion restricting ring is positioned at a position restricting the expansion of the outer peripheral region, and the dicing tape is pressed by the expanding ring to start expanding the dicing tape, the dicing tape comes into contact with the expansion restricting ring during the expansion of the dicing tape. At this time, the dicing tape is divided into an outer peripheral region located on the outer periphery side and an inner peripheral region located on the inner periphery side, with the contact portion contacting the expansion restricting ring as a boundary. Then, in the expanding operation by the expanding ring after the dicing tape comes into contact with the expansion restricting ring, only the inner peripheral region expands while the expansion of the outer peripheral region is restricted by the expansion restricting ring. In other words, the tension of the spring constant of the inner peripheral region, which is larger than the spring constant of the dicing tape, is applied to the workpiece. As a result, the tension applied to the workpiece increases, and the problem of non-division of the division line that occurs when the chip size is a small chip can be solved. When the division of the chips is completed, the expansion restricting ring is moved away from the position restricting the expansion of the outer peripheral region by the expansion retaining ring moving mechanism, and then the fitting portion of the expansion retaining ring is fitted onto the surface of the frame to maintain the expanded state of the dicing tape. In this way, according to the present invention, it is possible to simultaneously solve the problem of non-division of the planned division line that occurs when the chip size is small, and the problem of deterioration of the chip quality due to contact between the divided chips.

[0025] One aspect of the present invention preferably has a frame fixing member that fixes the frame, and the expansion restricting ring is detachably fixed to the frame fixing member at a position where it restricts the expansion of the outer circumferential region.

[0026] According to this aspect, by fixing the expansion restriction ring to the frame fixing member, the expansion restriction ring can be reliably fixed at a position that restricts the expansion of the outer circumferential region, thereby reliably restricting the expansion of the dicing tape.

[0027] In one aspect of the present invention, the frame fixing member is preferably configured in a ring shape having an opening larger than the inner diameter of the frame, and the expansion restriction ring is preferably attached to the inner peripheral surface of the opening of the frame fixing member.

[0028] According to one aspect of the present invention, the position expansion restriction ring can be attached at an appropriate position for restricting the expansion of the outer circumferential region.

[0029] In one aspect of the present invention, the frame fixing member is preferably provided with a fixing member for detachably fixing the expansion limiting ring.

[0030] According to one aspect of the present invention, the expansion restriction ring can be fixed to the frame fixing member by the fixing member.

[0031] In order to achieve the object of the present invention, the workpiece dividing method of the present invention comprises fixing an outer periphery of a dicing tape to a ring-shaped frame having an inner diameter larger than the outer diameter of the workpiece, and dividing the workpiece attached to the dicing tape into individual chips along a planned division line, and moving an expand ring arranged on the back side of the dicing tape opposite to the surface on which the workpiece is attached in a direction approaching the dicing tape relatively, so that an annular region of the dicing tape between the outer edge of the workpiece and the inner edge of the frame is pressed by the expand ring, thereby dividing the dicing tape into individual chips along a planned division line. the expansion restricting ring is abutted against a position of the annular region of the dicing tape that is outer than the pressing position of the expand ring while the expansion restricting ring is being pressed against the dicing tape, restricting the expansion of an outer circumferential region of the annular region that is located on the outer circumferential side of the abutment portion abutted against the expansion restricting ring; an expansion restricting ring retracting step of retracting the expansion restricting ring from the position where it restricts the expansion of the outer circumferential region; and an expansion state maintaining step of maintaining the expanded state of the dicing tape expanded by the expansion process with the expansion maintaining ring.

[0032] According to the work division method of the present invention, it is possible to simultaneously solve the problem of non-division of the planned division line that occurs when the chip size is small, and the problem of deterioration in chip quality due to contact between chips after division.

[0033] In one aspect of the present invention, it is preferable that after the expansion step, an expansion-restriction ring retraction step is performed, and after the expansion-restriction ring retraction step, an expansion state maintaining step is performed.

[0034] In one aspect of the present invention, an expansion retaining ring is placed on the back side of the dicing tape opposite the workpiece attachment surface, and the expanded state maintaining process preferably involves moving the expansion retaining ring in a direction approaching the dicing tape relatively, thereby engaging an elastically deformable engaging portion formed on the outer periphery of the expansion retaining ring with the surface of the frame to maintain the expanded state of the dicing tape. Effect of the Invention

[0035] According to the present invention, it is possible to simultaneously solve the problem of non-division along the division lines that occurs when the chip size is small, and the problem of deterioration in chip quality caused by contact between chips after division. [Brief description of the drawings]

[0036] [Figure 1] A structural diagram of a main part of a dividing stage of a workpiece dividing device according to an embodiment. [Diagram 2] FIG. 2 is an enlarged perspective view of a main part of the split stage shown in FIG. [Diagram 3] FIG. 1 is a cross-sectional view of a wafer unit showing the shape of the annular region during expansion. [Figure 4] A vertical cross-sectional view showing the expansion state of the dicing tape by the expansion retaining ring. [Diagram 5] Enlarged cross-sectional view of the main part of Figure 4 [Figure 6] Block diagram showing the control system of the workpiece separation device [Figure 7] 1 is a flowchart showing an example of a wafer dividing method. [Figure 8]Operational diagram of the workpiece dividing device [Figure 9] Operational diagram of the workpiece dividing device [Figure 10] A graph showing the expansion rate of the annular region and the inner peripheral region when an expansion restriction ring is used and when it is not used. [Figure 11] A graph showing the chip split ratio with and without the extended regulation ring. [Figure 12] An explanatory diagram of a wafer unit with a wafer attached [Figure 13] Vertical cross-sectional view of the wafer unit [Figure 14] Side view of the main part of the workpiece dividing device [Figure 15] Operation diagram of the workpiece dividing device [Figure 16] A longitudinal sectional view of a wafer unit into which wafers are separated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Hereinafter, preferred embodiments of the workpiece dividing device and the workpiece dividing method according to the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments within the scope of the present invention.

[0038] Fig. 1 is a vertical sectional view of a main part of a dividing stage provided in a work dividing device 10 according to an embodiment, and Fig. 2 is an enlarged perspective view of a main part of the dividing stage. Note that the size of the wafer unit divided by the work dividing device 10 is not limited, but in the embodiment, a wafer unit 2 on which a wafer 1 having a diameter of 300 mm is mounted as shown in Fig. 13 is exemplified.

[0039] 2, the workpiece dividing device 10 is a device that divides a wafer 1, on which dividing lines 5 are formed, into individual chips 6 along the dividing lines 5. A plurality of dividing lines 5 are formed in the X direction and the Y direction which are perpendicular to each other. In the embodiment, a wafer 1 in which the number of dividing lines 5 parallel to the X direction and the number of dividing lines 5 parallel to the Y direction are 300 each and the intervals between the dividing lines 5 are equal is illustrated, that is, a wafer 1 to be divided into chips 6 with a chip size of 1 mm.

[0040] 1 and 2, the wafer 1 is attached to the center of a dicing tape 3 whose outer periphery is fixed to a frame 4. The dicing tape 3 has a central region 3A that is circular in plan view to which the wafer 1 is attached, and an annular region 3B that is doughnut-shaped in plan view between the outer edge of the central region 3A (the outer edge of the wafer 1) and the inner edge of the frame 4.

[0041] The thickness of the wafer 1 is, for example, about 50 μm. For example, a PVC (polyvinyl chloride) tape is used as the dicing tape 3. The wafer 1 may be attached to the dicing tape 3 via a film-like adhesive such as DAF (Die Attach Film). For example, a PO (polyolefin)-based film-like adhesive may be used as the film-like adhesive.

[0042] The work division device 10 comprises a frame fixing member 7 (see Figures 14 and 15) that fixes the frame 4, an expanding ring 14 that abuts against the annular region 3B of the dicing tape 3 from below and presses and expands the dicing tape 3, an expansion restricting ring 16 that abuts against the dicing tape 3 when the dicing tape 3 is expanded by the expanding ring 14, and an expansion retaining ring 18 that maintains the expanded state of the dicing tape 3 expanded by the expanding ring 14.

[0043] The frame fixing member 7 is disposed on the same side of the dicing tape 3 as the attachment surface of the wafer 1, and the frame 4 is fixed to its underside 7A. The frame fixing member 7 is also disposed at a position spaced outward from the annular region 3B in the in-plane direction of the dicing tape 3 indicated by the arrow A so as not to come into contact with the annular region 3B expanded by the expand ring 14.

[0044] 2, the frame fixing member 7 has a ring shape with an opening 7B having a diameter of, for example, 361 mm, which is larger than the inner diameter (350 mm) of the frame 4, but the shape is not particularly limited. An example of the frame fixing member 7 is a rectangular plate material with an opening 7B, or a frame fixing member made up of a plurality of fixing members arranged at predetermined intervals along the outer periphery of the frame 4. The inscribed circles of these fixing members are set to be equal to the diameter of the opening 7B.

[0045] The expand ring 14 is disposed on the back surface of the dicing tape 3 opposite to the surface to which the wafer 1 is attached, and is formed in a ring shape having an expansion opening (opening) 14A that is smaller than the inner diameter (350 mm) of the frame 4 and larger than the outer diameter (300 mm) of the wafer 1. The expand ring 14 is disposed so as to be movable in a direction approaching the dicing tape 3 relatively. Specifically, the expand ring 14 is disposed so as to be movable in the vertical direction between an expansion position (position indicated by a two-dot chain line in FIG. 1) where the expand ring 14 presses the back surface of the annular region 3B of the dicing tape 3 to expand the annular region 3B, and a retreat position (position indicated by a solid line in FIG. 1) where the expand ring 14 is retreated downward from the expansion position.

[0046] The workpiece dividing device 10 is also provided with an expand ring moving mechanism 20 that moves the expand ring 14 up and down between the expanded position and the retracted position. A feed screw device is illustrated as an example of the expand ring moving mechanism 20, but an actuator such as an air cylinder device can be used instead. When the expand ring 14 located at the retracted position is moved toward the expanded position by the expand ring moving mechanism 20, the expand ring 14 is moved upward in the direction of arrow B toward the annular region 3B. As a result, the back surface of the annular region 3B is pressed against the expand ring 14 and radially expanded. Note that the annular region 3B may be pressed by the expand ring 14 by fixing the expand ring 14 and moving the wafer unit 2 downward in the direction of arrow C. The annular region 3B is abutted against the expansion restriction ring 16 when expanded by the expand ring 14.

[0047] The expansion restriction ring 16 is positioned on the same side of the dicing tape 3 as the attachment surface of the wafer 1, and is formed in a ring shape having an expansion restriction opening (opening) 16A that is smaller than the inner diameter (350 mm) of the frame 4 and larger than the outer diameter of the expand ring 14.

[0048] The expansion restriction ring 16 is arranged to be movable up and down between an expansion restriction position (a position restricting the expansion of the outer peripheral region 3E: a position shown by a solid line in FIG. 1) where the dicing tape 3 comes into contact when the dicing tape 3 expands, and a retreated position (a position shown by a two-dot chain line in FIG. 1) retreated upward from the expansion restriction position. The outer peripheral region 3E will be described later.

[0049] The workpiece dividing device 10 is also provided with an expansion restriction ring moving mechanism 22 that moves the expansion restriction ring 16 between the expansion restriction position and the retracted position. An air cylinder device is illustrated as an example of the expansion restriction ring moving mechanism 22, but an actuator such as a feed screw device can also be used instead.

[0050] In addition, it is preferable that the expansion restriction ring 16 is detachably attached to the inner peripheral surface of the opening 7B of the frame fixing member 7 at the expansion restriction position. This allows the expansion restriction ring 16 to be attached at an appropriate position that restricts the expansion of the outer peripheral region 3E. In addition, the expansion restriction ring 16 is fixed to the frame fixing member 7 by a fixing member at the expansion restriction position. The fixing member is not particularly limited, but an example is a fixing member using a plurality of pins 24. This fixing member has pins 24 arranged on the inner peripheral surface of the opening 7B so as to be able to protrude and retract, and holes 26 into which the protruding pins 24 fit are formed on the outer peripheral surface of the expansion restriction ring 16. That is, according to this fixing member, when the expansion restriction ring 16 is attached to the inner peripheral surface of the opening 7B, the pins 24 protrude from the frame fixing member 7 and fit into the holes 26 of the expansion restriction ring 16. This allows the expansion restriction ring 16 to be fixed to the inner peripheral surface of the opening 7B of the frame fixing member 7. In addition, the fixing position of the expansion restricting ring 16 relative to the frame fixing member 7 is not limited to the inner surface of the opening 7B, but may be any position that can properly restrict the expansion of the outer peripheral region 3E, for example, the surface of the frame fixing member 7 may be the fixing position.

[0051] Here, the frame fixing member 7 is fixed to a fixed structure of the work division device 10. As a result, the expansion restriction ring 16, which is positioned at the expansion restriction position and fixed to the frame fixing member 7 via the pin 24, is reliably fixed at the expansion restriction position. As shown in FIG. 3 described later, when the dicing tape 3 expands, the annular region 3B abuts against the expansion restriction ring 16, and the expansion of the outer circumferential region 3E is restricted by the expansion restriction ring 16. For this reason, the expansion restriction ring 16 receives a force from the annular region 3B. At this time, if the expansion restriction ring 16 is displaced upward by the force from the annular region 3B, the expansion restriction of the outer circumferential region 3E cannot be properly performed. However, in the embodiment, since the expansion restriction ring 16 is reliably fixed to the frame fixing member 7 via the pin 24 at the expansion restriction position, it is possible to prevent displacement due to the force from the annular region 3B, and the expansion restriction of the outer circumferential region 3E can be properly performed. Incidentally, instead of fixing the expansion restriction ring 16 to the frame fixing member 7 by the pin 24 which is a fixing member, the expansion restriction ring 16 may be fixed at the expansion restriction position by a fixing member (not shown).

[0052] FIG. 3 is a vertical cross-sectional view of the wafer unit 2, showing the shape of the annular region 3B in the middle of being expanded by the expand ring 14. As shown in FIG.

[0053] 3, when the annular region 3B is expanded by the expand ring 14, the annular region 3B abuts against the expansion restriction ring 16. Specifically, the annular region 3B abuts against an inner edge portion 16B on the back side of the expansion restriction ring 16. That is, the expansion restriction ring 16 abuts against a position of the annular region 3B that is outer than the pressing position of the expand ring 14.

[0054] 1, the diameter of the expansion restricting opening 16A is set to 338 mm. As a result, the width of the outer circumferential region 3E, the expansion of which is restricted by the expansion restricting ring 16, is set to 6 mm, and the width of the inner circumferential region 3F of the annular region 3B excluding the outer circumferential region 3E is set to 19 mm.

[0055] Here, the inner peripheral region 3F, the expansion of which is not restricted by the expansion restricting ring 16, of the annular region 3B is the region that substantially contributes to the division of the wafer 1. That is, as the width dimension of the inner peripheral region 3F is reduced, the spring constant of the inner peripheral region 3F increases, so that the tension applied from the inner peripheral region 3F to the wafer 1 can be increased. Therefore, it is preferable to set the width dimension of the inner peripheral region 3F according to the division conditions defined by the number of the planned division lines 5, etc.

[0056] The expansion retaining ring 18, which retains the expanded state of the dicing tape 3, is disposed on the back surface side of the dicing tape opposite to the surface to which the wafer 1 is attached. The expansion retaining ring 18 has a main ring 28 whose outer diameter is smaller than the inner diameter (350 mm) of the frame 4 and whose inner diameter is larger than the outer diameter of the expand ring 14, and an elastically deformable ring-shaped fitting portion 30 that is attached to the outer periphery of the main ring 28 and whose outer diameter (351.3 mm) is larger than the inner diameter (350 mm) of the frame 4.

[0057] Fig. 4 is a vertical cross-sectional view in which the expanded state of the dicing tape 3 is maintained by the expansion maintaining ring 18. Fig. 5 is an enlarged cross-sectional view of a main part of Fig. 4.

[0058] 4 and 5, the fitting portion 30 of the expansion retaining ring 18 fits into the surface 4A of the frame 4 via the annular region 3B of the dicing tape 3 at the fitting position shown by the solid line. This causes the expanded state of the dicing tape 3 to be maintained by the expansion retaining ring 18.

[0059] Before being expanded and held, the expansion retaining ring 18 is in a standby position (position shown by a solid line in FIG. 1) below the fitting position shown by the solid lines in FIG. 4 and FIG. 5, and is moved upward from the standby position to the fitting position by the expansion retaining ring moving mechanism 32 during expansion and holding. A feed screw device is illustrated as an example of the expansion retaining ring moving mechanism 32, but an actuator such as an air cylinder device can be used instead. When the expansion retaining ring 18 is raised by the expansion retaining ring moving mechanism 32, the fitting portion 30 abuts against the lower surface of the frame 4, and then the fitting portion 30 is pushed by the inner peripheral surface of the frame 4 and rises while elastically deforming, and the rise of the expansion retaining ring 18 is stopped at the position where the fitting portion 30 passes the inner peripheral surface of the frame 4. As a result, the fitting portion 30 is fitted to the surface 4A of the frame 4 at the fitting position as shown in FIG. 4 and FIG. It is also possible to fix the expansion retaining ring 18 and move the dicing tape 3 side in a direction approaching the expansion retaining ring 18. That is, the expansion retaining ring 18 is moved in a direction relatively approaching the dicing tape 3 so that the fitting portion 30 fits onto the surface 4A of the frame 4.

[0060] The operation of the expand ring moving mechanism 20 that drives the expand ring 14, the expansion restricting ring moving mechanism 22 that drives the expansion restricting ring 16, and the expansion retaining ring moving mechanism 32 that drives the expansion retaining ring 18 is controlled by a control unit 34 that overall controls the work dividing device 10, as shown in the block diagram of the control system in Figure 6.

[0061] An example of a workpiece dividing method performed by the control unit 34 will be described below.

[0062] First, the control unit 34 controls the expansion restriction ring moving mechanism 22 to position the expansion restriction ring 16 at the expanded restriction position, and then controls the expand ring moving mechanism 20 to move the expand ring 14 to the expanded position. Next, the control unit 34 controls the expansion restriction ring moving mechanism 22 to move the expansion restriction ring 16 to the retracted position. Next, the control unit 34 controls the expansion retaining ring moving mechanism 32 to move the expansion retaining ring 18 to the fitted position. Next, the control unit 34 controls the expand ring moving mechanism 20 to move the expand ring 14 to the retracted position.

[0063] Next, the above-mentioned work dividing method will be specifically described with reference to the flow chart of FIG. 7, and the operation explanatory diagrams of the work dividing device 10 shown in FIGS. 8(A) to (D) and FIGS. 9(E) to (H).

[0064] 7, the expand ring 14 is placed in the retracted position by the expand ring moving mechanism 20, the expansion limiting ring 16 is placed in the expanded limiting position by the expansion limiting ring moving mechanism 22, and the expansion retaining ring 18 is placed in the standby position by the expansion retaining ring moving mechanism 32, as shown in FIG.

[0065] Next, in a fixing process of step S110 in FIG. 7, the frame 4 of the wafer unit 2 is fixed to a frame fixing member 7 as shown in FIG. 8(B).

[0066] Next, in the expansion start process of step S120 in Fig. 7, as shown in Fig. 8(C), the expand ring moving mechanism 20 moves the expand ring 14 upward in the direction of arrow B from the retreated position in Fig. 8(A) to the expanded position, and the expansion of the entire area of ​​the annular region 3B begins. The annular region 3B may be cooled to a low temperature in advance by a cooling means (not shown) to increase the spring constant of the annular region 3B in advance. Examples of the cooling means include a contact type that cools the annular region 3B by contacting it, or an air-cooling type that cools the annular region 3B by spraying cold air onto it.

[0067] Next, in the expansion restriction process of step S130 in FIG. 7, when the upward movement amount of the expand ring 14 exceeds the thickness of the frame 4, as shown in FIG. 8(D), the annular region 3B abuts against the expansion restriction ring 16. At this time, as shown in FIG. 3, the annular region 3B is divided into an outer peripheral region 3E located on the outer peripheral side and an inner peripheral region 3F located on the inner peripheral side, with the abutment portion 3D abutting against the inner edge portion 16B of the expansion restriction ring 16 as a boundary. Then, the expansion of the outer peripheral region 3E of the annular region 3B is restricted by the expansion restriction ring 16. The expansion restriction process of S130 is a process performed when the expansion process from the expansion start process of S120 to the division process of S140 is performed. In other words, the expansion process is fixed and includes the expansion start process of S120, the expansion restriction process of S130, and the division process of S140.

[0068] Next, in the division process of step S140 in Fig. 7, as shown in Fig. 9(E), the upward movement of the expand ring 14 is continued, and the inner peripheral region 3F of the annular region 3B, excluding the outer peripheral region 3E in Fig. 3, is continuously expanded, thereby dividing the wafer 1 into individual chips 6. After this, when the expand ring 14 reaches the expansion position, the upward movement of the expand ring 14 is stopped. In other words, the expansion and fixation is completed at this point.

[0069] In the division step of S140, in the expansion operation by the expand ring 14 after the annular region 3B abuts against the inner edge portion 16B of the expansion restriction ring 16, only the inner region 3F expands while the expansion of the outer region 3E is restricted by the expansion restriction ring 16. In other words, the tension of the spring constant of the inner region 3F, which is larger than the spring constant of the annular region 3B, is applied to the wafer 1.

[0070] Specifically, the length of the annular region 3B that contributes to the division of the wafer 1 is shortened from 25 mm (width of the annular region 3B) to 19 mm (width of the inner peripheral region 3F), and the spring constant increases inversely proportionally. As a result, even if only the inner peripheral region 3F is expanded, the spring constant of the inner peripheral region 3F is greater than that of the annular region 3B, so that a tension sufficient to divide the wafer 1 into individual chips 6 can be applied even if the chip size is small (1 mm). Therefore, the work dividing device 10 can solve the problem of not dividing the planned division line that occurs when the chip size is small (1 mm).

[0071] The inner edge 16B of the expansion restriction ring 16, which is in line contact with the adhesive layer of the annular region 3B, is surface-treated to have an arithmetic mean roughness (Ra) of 1.6 (μm), for example. This makes it possible to prevent the inner edge 16B and the annular region 3B from slipping relative to each other due to the frictional force between them. In addition, the inner edge 16B is chamfered to C0.2, for example. This makes it possible to prevent the annular region 3B from breaking due to the reaction force when it receives an expansion force from the annular region 3B.

[0072] When the division process of S140 is completed, in the expansion restriction ring retraction process of step S150 in Figure 7, the expansion restriction ring 16 is moved to the retracted position by the expansion restriction ring moving mechanism 22 while the expand ring 14 is placed in the expanded position, as shown in Figure 9 (F).

[0073] Next, in the expanded state maintaining process of step S160 in Fig. 7, as shown in Fig. 9(G), the expansion retaining ring 18 is raised from the standby position toward the fitting position by the expansion retaining ring moving mechanism 32, and the fitting portion 30 of the expansion retaining ring 18 is fitted into the surface 4A of the frame 4 at the fitting position to maintain the expanded state of the dicing tape 3. That is, in the work division device 10 of the embodiment, after the expansion process is performed, the expansion restricting ring retracting process of S150 is performed, and after the expansion restricting ring retracting process of S150 is performed, the expanded state maintaining process of S160 is performed.

[0074] Next, in the expand ring retraction process of step S170 in Fig. 7, the expand ring 14 is moved downward to the retracted position by the expand ring moving mechanism 22 and placed at the retracted position, as shown in Fig. 9(H). At this time, the expansion of the dicing tape 3 by the expand ring 14 is released, but the fitting portion 30 of the expansion retaining ring 18 is fitted to the surface 4A of the frame 4, so that the expanded state is maintained without loosening. This makes it possible to prevent contact between the chips 6 caused by loosening of the expanded dicing tape 3, and therefore prevents deterioration of the quality of the chips 6.

[0075] According to the work dividing method using the work dividing device 10 of the embodiment as described above, it is possible to simultaneously solve the problem of non-division of the division line that occurs when the chip size is small, and the problem of deterioration in chip quality due to contact between chips after division.

[0076] In the workpiece dividing method of the embodiment, the expansion step from the expansion start step S120 to the division step S140 is performed, then the expansion restriction ring retract step S150 is performed, and then the expansion state holding step S160 is performed, but this is not limited to this step. For example, the expansion step from the expansion start step S120 to the division step S140 is performed, then the expansion state holding step S160 is performed, and then the expansion restriction ring retract step S150 may be performed. In this case, when the expansion holding ring 18 holds the expanded state of the dicing tape 3, the fitting portion 30 collides with the expansion restriction ring 16 at the expansion holding position. For this reason, in the expansion holding ring 18 of the embodiment, the expansion restriction ring retraction step S150 cannot be performed after the expansion state holding step S160. However, for example, by using the tape expansion holding ring disclosed in JP 2009-253071 A, the expansion restriction ring retraction step S150 can be performed after the expansion state holding step S160. The tape expansion holding ring described in JP 2009-253071 A is disposed on the same side of the dicing tape as the wafer attachment surface, and the tape expansion holding ring is pushed down from the raised position to the lowered position by the lifting mechanism. As a result, the dicing tape in the expanded state is sandwiched between the ring located below the dicing tape and the tape expansion holding ring, and the expanded state is maintained. Then, after the step of holding this expanded state, the expansion restriction ring retraction step S150 can be performed.

[0077] In addition, the workpiece division method is not limited to the above example. For example, after moving the expand ring 14 to the retreat position (S170), the expansion retaining ring 18 may be moved to the fitting position (S160). In the case of this division method, the dicing tape 3 is once loosened immediately after moving the expand ring 14 to the retreat position, but by moving the expansion retaining ring 18 to the fitting position, the dicing tape 3 is expanded again and this expanded state can be maintained. In the case of this division method, it is preferable to control the moving speed of the expand ring 14 to the retreat position to a low speed in order to mitigate collisions between the chips 6 caused by the dicing tape 3 suddenly loosening.

[0078] Here, the results of experiments conducted by the inventors to confirm the effects of the present invention will be described.

[0079] The graph in Fig. 10 shows the expansion rate of the annular region (diameter 350 mm) when no expansion restriction ring is used for the wafer unit 2 in Fig. 13, and the expansion rate of the inner peripheral region when the expansion restriction ring is used, with the diameter of the expansion restriction opening set to 346 mm, 342 mm, and 338 mm. Note that "MD (Machine Direction)" in Fig. 10 is the direction parallel to the feed direction during the manufacture of the dicing tape 3, and is the direction with the small spring constant. Also, "CD (Cross Direction)" is the direction perpendicular to MD, and is the direction with the large spring constant.

[0080] According to the experimental results in Figure 10, the expansion rate of the annular region when no expansion restriction ring was used was 6.1% in "MD" and 6.0% in "CD". In contrast, as the diameter of the expansion restriction opening was reduced to 346 mm, 342 mm, and 338 mm, the expansion rate of the inner circumference region increased to 6.8%, 7.5%, and 8.4% in "MD", and to 7.2%, 7.5%, and 8.1% in "CD". In other words, it was confirmed that the chip separation ability improved as the diameter of the expansion restriction opening was reduced.

[0081] The graph in Fig. 11 shows the division rate of chips when no expansion restriction ring is used (diameter 350 mm) for the wafer unit 2 in Fig. 13, and the division rate of chips when an expansion restriction ring is used and the diameter of the expansion restriction opening is set to 338 mm. Note that the division rate "with DAF" in Fig. 11 is the division rate of chips 6 when the wafer 1 is attached to the dicing tape 3 via the DAF, and the division rate "without DAF" is the division rate of chips 6 when the wafer 1 is directly attached to the dicing tape 3.

[0082] According to the experimental results in Fig. 11, the division rate of the chip 6 when the expansion restriction ring was not used was 15.0% "with DAF" and 41.0% "without DAF". In contrast, when an expansion restriction ring with an expansion restriction opening diameter of 338 mm was used, the division rate of the chip 6 increased to 61.0% "with DAF" and to 100% "without DAF". In other words, it was confirmed that the division ability of the chip 6 is improved by using the expansion restriction ring, whether "with DAF" or "without DAF".

[0083] From the above experimental results, it was confirmed that, according to the embodiment of the work division device 10, by restricting the expansion of the outer peripheral region 3E by the expansion restriction ring 16 and expanding only the inner peripheral region 3F, the expansion rate is increased compared to the annular region 3B and the tension applied to the wafer 1 can be increased, thereby solving the problem of non-division of the intended division line 5 that occurs when the chip size is small. [Explanation of symbols]

[0084] REFERENCE SIGNS LIST 1...wafer, 2...wafer unit, 3...dicing tape, 3A...central region, 3B...annular region, 3C...fixed region, 3D...contact portion, 3E...outer periphery region, 3F...inner periphery region, 4...frame, 5...planned division line, 6...chip, 7...frame fixing member, 8...expanding ring, 10...workpiece dividing device, 14...expanding ring, 14A...expansion opening, 16...expansion restricting ring, 16A...expansion restricting opening, 16B...inner edge, 18...expanding retaining ring, 20...expanding ring moving mechanism, 22...expanding restricting ring moving mechanism, 24...pin, 26...hole portion, 28...main body ring, 30...fitting portion, 32...expanding retaining ring moving mechanism, 34...control portion

Claims

1. A workpiece dividing device in which an outer periphery of a dicing tape is fixed to a ring-shaped frame having an inner diameter larger than an outer diameter of a workpiece, and the workpiece attached to the dicing tape is divided into individual chips along a planned division line, an expand ring that is disposed on a back surface side of the dicing tape opposite to the work attachment surface, is formed in a ring shape having an opening smaller than an inner diameter of the frame, and presses the dicing tape to expand it; an expansion restriction ring arranged on the same side of the dicing tape as the application surface of the workpiece, the expansion restriction ring being formed in a ring shape having an opening smaller than the inner diameter of the frame and larger than the outer diameter of the expansion ring, the expansion restriction ring being brought into contact with the dicing tape when the dicing tape is expanded, and restricting the expansion of an outer circumferential region of the dicing tape located on the outer circumferential side of the contact portion brought into contact with the expansion restriction ring; an expansion retaining ring arranged on a back surface side of the dicing tape opposite to the attachment surface of the workpiece, the expansion retaining ring being formed in a ring shape having a fitting portion larger than an inner diameter of the frame, the fitting portion fitting into the surface of the frame to retain the expanded state of the dicing tape; A workpiece dividing device comprising:

2. A frame fixing member for fixing the frame is provided, The workpiece dividing device according to claim 1 , wherein the expansion restricting ring is detachably fixed to the frame fixing member at a position where the expansion of the outer circumferential side region is restricted.

3. The frame fixing member is configured in a ring shape having an opening larger than an inner diameter of the frame, The workpiece dividing device according to claim 2 , wherein the expansion restricting ring is attached to an inner circumferential surface of the opening of the frame fixing member.

4. The workpiece dividing device according to claim 2 or 3, wherein the frame fixing member is provided with a fixing member for detachably fixing the expansion restricting ring.

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