Workpiece splitting device and workpiece splitting method

Abstract

To provide a workpiece dividing device and a workpiece dividing method that can effectively eliminate slack caused by plastic deformation of a dicing tape after expansion.SOLUTION: A method includes an expansion step of expanding a dicing tape 3, a heating step of thermally shrinking the dicing tape 3 by heating at least the area of the dicing tape 3 where the workpiece is attached, and an expanded state maintaining step of maintaining the expanded state of the thermally shrunk dicing tape 3.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a work dividing apparatus and a work dividing method, and more particularly to a work dividing apparatus and a work dividing method for dividing a work such as a semiconductor wafer along a planned dividing line into individual chips.

Background Art

[0002] Conventionally, in the manufacture of semiconductor chips (hereinafter referred to as chips), a semiconductor wafer (hereinafter referred to as a wafer) in which a planned dividing line is formed in advance by half-cutting with a dicing blade or forming a modified region by laser irradiation is divided along the planned dividing line into individual chips. A work dividing apparatus is known (see Patent Document 1 and the like). The work dividing apparatus of Patent Document 1 divides a wafer into individual chips by expanding a dicing tape to which the wafer is attached by expansion.

[0003] In the field of work dividing apparatuses, it is also required to prevent deterioration of chip quality caused by contact between chips after division by maintaining the expanded state of the dicing tape expanded by expansion.

[0004] To satisfy this requirement, the work dividing apparatus of Patent Document 1 includes a sub-ring. This sub-ring has a function of holding the dicing tape expanded by expansion 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 peripheral portion of the dicing tape and the surface of the frame immediately after rising from the back side of the dicing tape toward the dicing tape and passing through the frame. Thereby, even after the expansion of the dicing tape by expansion is completed, the expanded state of the dicing tape can be maintained. By maintaining the expanded state of the dicing tape in this way, the slack of the dicing tape can be prevented, and thus deterioration of chip quality caused by contact between chips can be prevented.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-51368 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, with conventional workpiece splitting equipment, it was difficult to expand the dicing tape without causing any plastic deformation. In particular, as the chip size decreases, greater tension is applied to the dicing tape, so dicing tapes to which wafers with small chip sizes are attached tend to be easily plastically deformed as a whole during expansion.

[0007] In Patent Document 1, the slack caused by plastic deformation of the dicing tape after expansion is removed by a sub-ring. However, there was a problem in that it was difficult to sufficiently remove the slack that occurred throughout the entire dicing tape with the sub-ring.

[0008] This invention has been made in view of the above problems, and aims to provide a workpiece splitting device and a workpiece splitting method that can effectively remove loosening caused by plastic deformation of the dicing tape after expansion. [Means for solving the problem]

[0009] To achieve the objectives of the present invention, the workpiece splitting apparatus of the present invention is a workpiece splitting apparatus that splits a workpiece attached to a dicing tape and mounted on a frame into individual chips along a planned splitting line, comprising: an expander ring that applies tension to the dicing tape to expand it; a heating unit that applies heat to the entire dicing tape expanded by the expander ring to cause the entire dicing tape to shrink; and an expansion holding ring that expands the dicing tape that has shrunk by the heating unit to maintain the expanded state of the dicing tape.

[0010] In one embodiment of the present invention, it is preferable that the heating section includes a heating member that emits radiant heat and a heat reflecting member that reflects the radiant heat emitted from the heating member toward the dicing tape.

[0011] In one embodiment of the present invention, the heating element is preferably a halogen lamp.

[0012] To achieve the objectives of the present invention, the present invention provides a workpiece division method for dividing a workpiece attached to a dicing tape and mounted on a frame into individual chips along a planned division line, comprising: an expansion step of applying tension to the dicing tape to expand it; a heating step of applying heat to the entire dicing tape expanded in the expansion step to cause the entire dicing tape to shrink; and an expanded state holding step of expanding the dicing tape that has shrunk in the heating step to maintain the expanded state of the dicing tape.

[0013] In one embodiment of the present invention, it is preferable that the heating step applies radiant heat to the entire dicing tape. [Effects of the Invention]

[0014] According to the present invention, sagging caused by plastic deformation of the dicing tape after expansion can be effectively removed. [Brief explanation of the drawing]

[0015] [Figure 1] Cross-sectional view showing the structure of the workpiece splitting device of the embodiment. [Figure 2] Enlarged perspective view of the main part showing the structure of the extension. [Figure 3] A longitudinal cross-sectional view of the main part of a wafer unit showing the shape of the annular region during expansion. [Figure 4] A longitudinal cross-sectional view showing the expanded state of the dicing tape by the expansion retaining ring. [Figure 5] Figure 1 shows an enlarged perspective view of the main components of the heating section of the workpiece splitting device. [Figure 6] Block diagram showing the control system of the workpiece dividing apparatus [Figure 7] Flowchart showing an example of the wafer dividing method [Figure 8] Operation explanatory diagram of the workpiece dividing apparatus [Figure 9] Operation explanatory diagram of the workpiece dividing apparatus [Figure 10] Operation explanatory diagram of the workpiece dividing apparatus [Figure 11] Explanatory diagram of the wafer unit with the wafer attached [Figure 12] Vertical cross-sectional view of the wafer unit [Figure 13] Operation diagram of the workpiece dividing apparatus [Figure 14] Vertical cross-sectional view of the wafer unit with the wafer divided

Mode for Carrying Out the Invention

[0016] Hereinafter, preferred embodiments of the workpiece dividing apparatus 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.

[0017] Before explaining the workpiece dividing apparatus 10 (see FIG. 1) according to the embodiment, the wafer to be divided by the workpiece dividing apparatus 10 of the embodiment will be explained.

[0018] FIG. 11 is an explanatory diagram of a wafer unit 2 with a disk-shaped wafer 1 attached thereto. FIG. 11(A) is a perspective view of the wafer unit 2, and FIG. 11(B) is a vertical cross-sectional view of the wafer unit

[0019] The wafer 1 is attached to the central portion of a dicing tape 3 having an adhesive layer formed on one side, and the dicing tape 3 has its outer peripheral portion fixed to a rigid metal ring-shaped frame 4.

[0020] The thickness of wafer 1 is, for example, about 50 μm, and the thickness of dicing tape 3 is, for example, about 100 μm. For dicing tape 3, a PVC (polyvinyl chloride) tape is used. Alternatively, wafer 1 may be attached to dicing tape 3 via a film-type adhesive such as DAF (Die Attach Film). For example, a PO (polyolefin)-based film-type adhesive can be used.

[0021] In the workpiece splitting apparatus 10 shown in Figure 1, the upper surface 4A of the frame 4 of the wafer unit 2 is detachably fixed to the lower surface 7A of the fixing part 7. After this, an expander ring 16 moves upward from below the wafer unit 2, and the dicing tape 3 is pressed and expanded radially by this expander ring 16. The tension generated in the dicing tape 3 at this time is applied to the planned splitting line 5 (see Figure 11) of the wafer 1, thereby splitting the wafer 1 into individual chips 6.

[0022] In this specification, as shown in Figure 11(B), the circular area in plan view of the dicing tape 3 to which the wafer 1 is attached is referred to as the central area 3A, the donut-shaped area in plan view 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 outermost donut-shaped area in plan view that is fixed to the frame 4 is referred to as the fixed area 3C. The annular area 3B is the area that is pressed and expanded by the expanding ring 16.

[0023] In the workpiece splitting apparatus 10, the force required to split the wafer 1, that is, the tension that must be generated in the annular region 3B to split the wafer 1 into individual chips 6, is known to increase as the number of planned splitting lines 5 increases. Regarding the number of planned splitting lines 5, for example, as shown in Figure 12, if the wafer 1 has a diameter D1 of 300 mm and a chip size of 5 mm, approximately 120 planned splitting lines 5 (60 in each of the X and Y directions) are formed, and if the chip size is 1 mm, approximately 600 planned splitting lines 5 are formed. Therefore, the tension that must be generated in the annular region 3B must be higher when the chip size is 1 mm than when it is 5 mm.

[0024] Furthermore, the inner diameter D2 (the diameter of the inner edge of the frame) of the frame 4 on which the wafer 1 with a diameter D1 of 300 mm is mounted is defined as 350 mm according to the SEMI standard (G74-0699 Specification for Tape Frames for 300 mm Wafers). According to this standard, there is an annular region 3B with a width dimension a of 25 mm between the outer edge of the wafer 1 and the inner edge of the frame 4. Also, as shown in Figure 11(B), the fixing part 7 that secures the frame 4 is positioned outward from the annular region 3B in the in-plane direction of the dicing tape 3 indicated by arrow A, so as not to come into contact with the annular region 3B that is expanded by the expanding ring 16.

[0025] Here, the force that divides the wafer 1 generated by the upward movement of the expanding ring 16 is (i) a force that expands the entire area of ​​the annular region 3B, (ii) a force that divides the wafer 1 into chips 6, and (iii) a force that expands the dicing tape 3 between adjacent chips 6. It can be divided into two forces.

[0026] As shown in the operation diagrams of the workpiece splitting device in Figures 13(A) to (E), the expanding ring 16 comes into contact with the annular region 3B of the dicing tape 3, and when the dicing tape 3 begins to expand due to the upward movement of the expanding ring 16 (Figure 13(A)), the annular region 3B with the lowest spring constant begins to expand first (Figure 13(B)). This generates tension in the annular region 3B, and when this tension increases to a certain extent, the increased tension is transmitted to the wafer 1, and the splitting of the wafer 1 into chips 6 begins (Figure 13(C)). Once the wafer 1 is split into individual chips 6, the expansion of the annular region 3B and the expansion of the dicing tape 3 between the chips 6 proceed simultaneously (Figures 13(D) to (E)).

[0027] For example, in a wafer 1 with a diameter D1 of 300 mm, if the chip size is 5 mm or larger, the tension generated in the annular region 3B allows for easy separation into individual chips 6. However, in recent years, with the miniaturization of circuit patterns formed on wafer 1, chips smaller than 1 mm have appeared. In this case, the number of planned division lines 5 for dividing wafer 1 increases, resulting in a greater force required to divide wafer 1, exceeding the tension generated by the expansion of the annular region 3B. Consequently, as shown in the longitudinal cross-sectional view of the wafer unit 2 in Figure 14, even after the expansion operation by the expanding ring 16 is completed, a problem arises where some of the planned division lines 5 formed on wafer 1 remain undivided.

[0028] Therefore, in the embodiments described below, as an example of a wafer 1 to be divided, we will use a wafer 1 with a diameter D1 of 300 mm as shown in Figure 12, where the number of division lines 5 parallel to the X direction and the number of division lines 5 parallel to the Y direction are both 300, and the chip size is 1 mm. Then, we will describe a workpiece division apparatus and a workpiece division method that can effectively remove the loosening caused by the plastic deformation of the dicing tape 3 that occurs after expansion, while resolving the previously described problem of undivided wafer 1.

[0029] Figure 1 is a cross-sectional view showing the structure of a workpiece splitting device 10 according to an embodiment. The workpiece splitting device 10 includes an expansion unit 12 and a heating unit 14. Figure 2 is an enlarged perspective view of the main part showing the structure of the expansion unit 12.

[0030] As shown in Figure 2, the expansion section 12 includes a fixing section 7 for fixing the frame 4, an expanding ring 16 that presses the annular region 3B of the dicing tape 3 from below to above to expand the dicing tape 3, an expansion restricting ring 17 that contacts the annular region 3B of the dicing tape 3 from above, and an expansion retaining ring (also called a sub-ring) 18 that maintains the expanded state of the dicing tape 3 expanded by the expanding ring 16. These fixing section 7, expanding ring 16, expansion restricting ring 17, and expansion retaining ring 18 are arranged in the working chamber 20 of the expansion section 12 (see Figure 1).

[0031] The fixing portion 7 is positioned on the same side as the wafer 1 attachment surface of the dicing tape 3, and the upper surface 4A of the frame 4 is detachably fixed to its lower surface 7A. The shape of the fixing portion 7 is ring-shaped, having an opening 7B with a diameter D3 (see Figure 2) of 361 mm, which is larger than the inner diameter D2 (350 mm: see Figure 12) of the frame 4.

[0032] The expanding ring 16 is positioned on the back side of the dicing tape 3 opposite to the surface to which the wafer 1 is attached, and has an expansion opening 16A that is smaller than the inner diameter D2 of the frame 4 (350 mm: see Figure 12) and larger than the outer diameter D1 of the wafer 1 (300 mm: see Figure 12). The expanding ring 16 is positioned to be movable in a direction that moves it relatively closer to the dicing tape 3. Specifically, the expanding ring 16 is positioned to be movable vertically between an expansion position (shown by the dashed line in Figure 1) where it presses the back side of the annular region 3B of the dicing tape 3 upward to expand the annular region 3B, and a retracted position (shown by the solid line in Figure 1) where it is retracted downward from the annular region 3B.

[0033] The workpiece splitting device 10 is equipped with an expander ring moving mechanism 22 that moves the expander ring 16 up and down between an expanded position and a retracted position. As an example of the expander ring moving mechanism 22, a lead screw device is shown, but an actuator such as an air cylinder device can also be used instead. When the expander ring 16, which is in the retracted position, is moved toward the expanded position by the expander ring moving mechanism 22, the expander ring 16 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 by the expander ring 16 and expands radially.

[0034] The expansion restriction ring 17 is positioned on the same side as the wafer 1 attachment surface on the dicing tape 3 and has an expansion restriction opening 17B that is smaller than the inner diameter D2 of the frame 4 (350 mm: see Figure 12) and larger than the outer diameter of the expand ring 16. As an example, the diameter D4 of the expansion restriction opening 17B (see Figure 1) is 338 mm.

[0035] The expansion regulating ring 17 is positioned to be vertically movable between a regulating position (indicated by the dashed line in Figure 1) where its lower edge 17A abuts against the surface of the annular region 3B, and a retracted position (indicated by the solid line in Figure 1) where it is retracted upward from the regulating position.

[0036] The restricting position is the position where the expansion of the outer peripheral region 3E is restricted by the expansion restricting ring 17. In Figure 1, the lower edge 17A of the expansion restricting ring 17 is set to a position where it is flush with the lower surface 4B of the frame 4. However, the restricting position is not limited to this position, but can be any position that can restrict the expansion of the outer peripheral region 3E. The outer peripheral region 3E is the region located on the outer side of the annular region 3B, separated by the contact portion 3D (see Figure 3) that abuts against the lower edge 17A of the expansion restricting ring 17. The region of the annular region 3B excluding the outer peripheral region 3E is the inner peripheral region 3F, and this inner peripheral region 3F is the region that is expanded by the expand ring 16.

[0037] Returning to Figure 1, the workpiece splitting device 10 is equipped with an expansion restricting ring movement mechanism 23 that moves the expansion restricting ring 17 up and down between the restricting position and the retracted position. An air cylinder device is shown as an example of the expansion restricting ring movement mechanism 23, but an actuator such as a lead screw device can also be used instead.

[0038] Figure 3 is an enlarged cross-sectional view of the main part of the wafer unit 2, showing the shape of the annular region 3B during expansion by the expanding ring 16.

[0039] As shown in Figure 3, when the annular region 3B is expanded by the expanding ring 16, the expansion restricting ring 17 is positioned in a restricting position prior to the expansion operation by the expanding ring 16. In other words, the expansion of the outer peripheral region 3E of the dicing tape 3 is restricted in advance by the expansion restricting ring 17. Therefore, according to the workpiece splitting device 10 of this embodiment, the expansion of the inner peripheral region 3F begins immediately after the expanding ring 16 contacts the annular region 3B.

[0040] In this embodiment, as shown in Figure 1, the diameter D4 of the expansion restricting opening 17B is set to 338 mm. Therefore, the width dimension b of the outer peripheral region 3E whose expansion is restricted by the expansion restricting ring 17 is set to 6 mm, and the width dimension c of the inner peripheral region 3F which is expanded by the expand ring 16 is set to 19 mm.

[0041] Here, the inner peripheral region 3F of the annular region 3B, which is expanded by the expanding ring 16, is the region that substantially contributes to the division of the wafer 1. As the width dimension c of this inner peripheral region 3F is reduced, the spring constant of the inner peripheral region 3F increases, and the tension applied from the inner peripheral region 3F to the wafer 1 increases. For this reason, the diameter D4 of the expansion restricting opening 17B that determines the width dimension c of the inner peripheral region 3F is set according to the division conditions defined by the number of division lines 5, etc.

[0042] On the other hand, the expansion retaining ring 18 is positioned on the back side of the dicing tape 3, opposite to the surface to which the wafer 1 is attached. As shown in Figure 4, the expansion retaining ring 18 has a main ring 24 whose outer diameter D5 is smaller than the inner diameter D2 (350 mm) of the frame 4 and whose inner diameter D6 is larger than the outer diameter of the expand ring 16, and an elastically deformable ring-shaped fitting portion 26 attached to the outer circumference of the main ring 24, having an outer diameter D7 (351.3 mm) that is larger than the inner diameter D2 (350 mm) of the frame 4. Figure 4 is a longitudinal cross-sectional view showing the expanded state of the dicing tape 3 held by the expansion retaining ring 18.

[0043] The expansion and retention ring 18 is positioned in a standby position as shown by the solid line in Figure 1 before expansion and retention, and is moved upward from the standby position by the expansion and retention ring moving mechanism 28 when expansion and retention occurs. As an example of the expansion and retention ring moving mechanism 28, a lead screw device is shown, but an actuator such as an air cylinder device can also be used instead.

[0044] When the expansion retaining ring 18 is raised by the expansion retaining ring moving mechanism 28, the fitting portion 26 comes into contact with the lower surface of the frame 4. Subsequently, the fitting portion 26 rises while elastically deforming as it is pushed against the inner circumferential surface of the frame 4 by the continued upward movement of the expansion retaining ring 18. The upward movement of the expansion retaining ring 18 stops when the fitting portion 26 has passed the inner circumferential surface of the frame 4. As a result, the fitting portion 26 is fitted to the upper surface 4A of the frame 4 at the fitting position shown in Figure 4.

[0045] As will be described later, in the workpiece splitting device 10 of this embodiment, once the splitting process by the expanding ring 16 (S140: see Figure 7) is completed, the dicing tape 3 is heated by the heating unit 14 (S150: see Figure 7), and then the expanded state holding process by the expansion holding ring 18 (S160: see Figure 7) is performed.

[0046] Returning to Figure 1, let's explain the heating section 14.

[0047] The heating section 14 includes a heating chamber 30 that heats the dicing tape 3, which has been plastically deformed by the expansion operation of the expand ring 16.

[0048] The heating chamber 30 is located next to the workroom 20 via an insulating wall 32. The heating chamber 30 is also connected to the workroom 20 via an opening 36 that is opened and closed by a door 34. Therefore, the wafer units 2, which have been divided into individual chips 6 by the expansion unit 12, are transported from the workroom 20 to the heating chamber 30 via the opening 36 by a transport device (not shown) without the expanded state of the dicing tape 3 being held by the expansion holding ring 18. Once the wafer units 2 have been transported to the heating chamber 30, the frame 4 is placed on the ring-shaped table 38 of the heating chamber 30 by the aforementioned transport device. In this embodiment of the workpiece dividing device 10, since the heating chamber 30 is located next to the workroom 20, the dicing tape 3 expanded in the workroom 20 can be efficiently transported to the heating chamber 30 and heated.

[0049] Below the table 38 of the heating chamber 30, a plurality of radiant heat radiating members 40 are arranged to heat the entire surface of the dicing tape 3 by radiant heat.

[0050] Now, let's explain the heating means for applying heat to the dicing tape 3. These heating means include radiant heat, as well as means that utilize heat conduction (contact) or heat transfer (convection).

[0051] Incidentally, if heat conduction is used as the heating method, it is difficult to uniformly heat the entire dicing tape 3 because it is loose and irregular in shape, making it difficult to contact the entire dicing tape 3. On the other hand, if heat transfer is used as the heating method, the entire dicing tape 3 can be heated uniformly, but it is difficult to use because there is a risk that tiny dust particles present in the air will adhere to the wafer 1 and contaminate it.

[0052] Therefore, in the workpiece splitting device 10 of this embodiment, a radiant heat radiating member 40 that emits radiant heat is adopted as a preferred form of heating means. The heating method using radiant heat can resolve the aforementioned problems of heat conduction and heat transfer, and also has the advantage of suppressing unnecessary temperature rise because it can heat only the area irradiated with infrared light.

[0053] Figure 5 is an enlarged perspective view showing the main components of the heating section 14 shown in Figure 1. As shown in Figure 5, the radiant heat emission member 40 has halogen lamps 42. There are multiple halogen lamps 42 in total (five in Figure 5), and these halogen lamps 42 are arranged at equal intervals on the same horizontal plane directly below the dicing tape 3, and their axial directions are parallel.

[0054] While it is possible to heat the entire dicing tape 3 using only the halogen lamp 42, the illuminance may differ between the portion of the dicing tape 3 directly above the halogen lamp 42 where infrared light is directly shone, and the portion directly above the area between the lamps where the halogen lamp 42 is not present. In such cases, temperature unevenness occurs in the dicing tape 3, making it difficult to heat the entire dicing tape 3 uniformly.

[0055] Therefore, in the embodiment, the heating unit 14 has a reflector 44, which is an example of a heat reflective member of the present invention, positioned adjacent to the lower side of the halogen lamp 42, so that the infrared light emitted downward and to the sides from the halogen lamp 42 is reflected by the reflector 44 and irradiated to the area directly above the space between the lamps. As a result, the heating unit 14 of the embodiment can heat the entire surface of the dicing tape 3 more uniformly, and thus the entire dicing tape 3 can be heat-shrinked more uniformly.

[0056] Furthermore, the reflector 44 of this embodiment has a mountain-shaped bottom portion 44A located below the halogen lamp 42, and a pair of wall portions 44B, 44B positioned on both sides of the bottom portion 44A toward the dicing tape 3 and inclined out of the plane of the dicing tape 3. With a reflector 44 of this shape, infrared light from the halogen lamp 42 can be efficiently reflected toward the portion directly above the space between the lamps. As a result, the entire surface of the dicing tape 3 can be heated more uniformly, and the entire dicing tape 3 can be thermally shrunk more uniformly. Note that the reflector 44 is not limited to the shape described above. That is, the reflector 44 may have a shape that can efficiently reflect infrared light from the halogen lamp 42 toward the portion directly above the space between the lamps, for example, a reflector with a vertical cross-section that is convex downwards.

[0057] Figure 6 is a functional block diagram of the control unit 48 of the workpiece splitting device 10. The control unit 48 shown in Figure 6 has various arithmetic processing circuits including a CPU (central processing unit) and a storage medium such as memory, and controls the overall operation of the workpiece splitting device 10, including the expanded ring moving mechanism 22, the expanded regulating ring moving mechanism 23, and the expanded holding ring moving mechanism 28 described above. In addition to the expanded ring moving mechanism 22, the expanded regulating ring moving mechanism 23, and the expanded holding ring moving mechanism 28, a halogen lamp power supply 46 and a radiation thermometer 50 are connected to this control unit 48.

[0058] The halogen lamp power supply 46, under the control of the control unit 48, supplies power to the halogen lamp 42 and controls the voltage of the power supplied to the halogen lamp 42. The halogen lamp 42 lights up and emits infrared light upon receiving power from the halogen lamp power supply 46. The amount of infrared light emitted from the halogen lamp 42 is controlled by the magnitude of the voltage applied to the halogen lamp 42 from the halogen lamp power supply 46. In other words, by changing the voltage applied to the halogen lamp 42 from the halogen lamp power supply 46, the temperature at which the halogen lamp 42 heats the dicing tape 3 is changed.

[0059] The radiation thermometer 50 is installed in the heating chamber 30 shown in Figure 1 and measures the temperature of the dicing tape 3. In this embodiment, the radiation thermometer 50 is positioned in the heating chamber 30 to measure the temperature of the annular region 3B of the dicing tape 3, but the position is not limited to this. For example, the radiation thermometer 50 may be placed below the dicing tape 3 in the heating chamber 30, and the temperature of the central region 3A may be measured by the radiation thermometer 50. The radiation thermometer 50 outputs the temperature measurement result of the dicing tape 3 to the control unit 48.

[0060] The control unit 48 functions as a voltage control unit 48a by executing a control program (not shown) stored in memory or the like. When power is supplied from the halogen lamp power supply 46 to the halogen lamp 42, the voltage control unit 48a controls the magnitude of the voltage applied to the halogen lamp 42 by the halogen lamp power supply 46. Specifically, the power control unit 48a controls the magnitude of the voltage applied to the halogen lamp 42 based on the temperature measurement result of the dicing tape 3 input from the radiation thermometer 50, so that the temperature of the dicing tape 3 does not exceed a predetermined upper limit temperature. In this way, the amount of infrared light emitted from the halogen lamp 42 is adjusted so that the temperature of the dicing tape 3 does not exceed the upper limit temperature. The upper limit temperature is set based on the material of the base material of the dicing tape 3.

[0061] Next, the workpiece splitting method of the embodiment will be described in accordance with the flowchart in Figure 7, and the operation diagrams of the workpiece splitting device 10 shown in Figures 8(A) to (D), 9(A) to (B), and 10(A) to (E).

[0062] First, in the arrangement step (S100) shown in Figure 7, the expand ring 16 and the expansion restricting ring 17 are positioned in their retracted positions, as shown in Figure 8(A), while the expansion holding ring 18 is positioned in its standby position.

[0063] Next, in the fixing process (S110) shown in Figure 7, the frame 4 of the wafer unit 2 is fixed to the fixing part 7, as shown in Figure 8(B).

[0064] Next, in the expansion restriction process (S120) shown in Figure 7, as shown in Figure 8(C), the expansion restriction ring 17 is moved from the retracted position to the restriction position, and the lower edge 17A of the expansion restriction ring 17 is brought into contact with the surface of the annular region 3B.

[0065] Next, in the expansion initiation step (S130) shown in Figure 7, the expanding ring 16 is moved upward from the retracted position shown in Figure 7(A) toward the expanded position, as shown in Figure 8(D), thereby initiating the expansion of the annular region 3B.

[0066] In this expansion initiation step (S130), the lower edge 17A of the expansion restricting ring 17 is in contact with the surface of the annular region 3B in advance, restricting the expansion of the outer peripheral region 3E, so that the inner peripheral region 3F (see Figure 1) is expanded by the expand ring 16. The aforementioned expansion restricting step (S120) is performed together with the expansion steps from the expansion initiation step (S130) to the end of the division step (S140) described later. In other words, the expansion steps of the present invention refer to the steps from the expansion initiation step (S130) to the end of the division step (S140).

[0067] Next, in the splitting process (S140) shown in Figure 7, as shown in Figure 9(A), the expansion of the inner circumference region 3F (see Figure 3) continues by the upward movement of the expanding ring 16, during which the wafer 1 is sequentially divided into individual chips 6. After this, as shown in Figure 9(B), when the expanding ring 16 reaches the expanded position, the upward movement of the expanding ring 16 is stopped. At this point, the expansion process described above is completed.

[0068] In this expansion process, the expansion of the outer peripheral region 3E is restricted by the expansion restricting ring 17, while only the inner peripheral region 3F is expanded by the expansion ring 16. In other words, the tension generated in the inner peripheral region 3F is applied to the wafer 1.

[0069] Specifically, in the expansion process, by using an expansion restricting ring 17 with a diameter D4 (see Figure 1) of 338 mm for the expansion restricting opening 17B, the length of the region contributing to the division of wafer 1 is reduced from 25 mm (width dimension a of the annular region 3B: see Figure 12) to 19 mm (width dimension c of the inner circumference region 3F: see Figure 1). As a result, the spring constant of the inner circumference region 3F increases, and a tension corresponding to this increased spring constant is applied to wafer 1.

[0070] Therefore, according to the workpiece division method of this embodiment, since it includes an expansion restriction step (S120) using the expansion restriction ring 17, even if the chip size is small (1 mm), it is possible to apply enough tension to the wafer 1 to divide it into individual chips 6. Thus, the problem of undivided planned division lines that occurs when the chip size is small (1 mm) can be resolved.

[0071] Incidentally, after the splitting process (S140), the dicing tape 3 requires a large increase in the upward movement of the expander ring 16 in order to split the wafer 1 into small chips 6. As a result, plastic deformation of the dicing tape 3 is unavoidable, and excess slack is created throughout the wafer 1. Such excess slack is difficult to remove completely even with the expansion retaining ring 18. For this reason, even if an expanded state retention process (S160) using the expansion retaining ring 18 is performed immediately after the splitting process (S140), the expanded state of the dicing tape 3 cannot be maintained.

[0072] Therefore, in the workpiece splitting apparatus 10 of this embodiment, as shown in Figure 7, the heating step S150 is provided after the completion of the splitting step S140 and before the expanded state holding step S160.

[0073] The heating process of S150 will be explained in detail below.

[0074] First, as shown in Figure 10(A), the expand ring 16 is moved downward from the expanded position to the retracted position, and the expansion restricting ring 17 is moved upward from the restricting position to the retracted position. Next, the fixing of the wafer unit 2 frame 4 to the fixing part 7 is released. Then, the door 34 of the work room 20 (see Figure 1) is opened, and the wafer unit 2 is transported from the work room 20 through the opening 36 into the heating room 30 using a transport device (not shown). Then, the frame 4 of the wafer unit 2 is placed on the table 38 of the heating room 30 as shown in Figure 10(B) using a transport device (not shown). After this, the door 34 is closed to seal the heating room 30.

[0075] Next, the control unit 48 in Figure 6 drives the halogen lamp power supply 46 to light up all the halogen lamps 42, 42… as shown in Figure 10(C). When the halogen lamps 42, 42… are lit, the portion of the dicing tape 3 directly above the lamps is illuminated by direct infrared light from the halogen lamps 42, and the portion directly above the spaces between the lamps is illuminated by reflected infrared light from the reflector 44. As a result, the entire surface of the dicing tape 3 is heated uniformly.

[0076] Furthermore, the reflector 44 has a mountain-shaped bottom portion 44A positioned below the halogen lamp 42, and a pair of wall portions 44B, 44B positioned on both sides of the bottom portion 44A toward the dicing tape 3 and inclined out of the plane of the dicing tape 3. By applying a reflector 44 with such a configuration, infrared light from the halogen lamp 42 can be efficiently reflected toward the portion directly above the space between the lamps, so that the entire surface of the dicing tape 3 is heated more uniformly.

[0077] The dicing tape 3 gradually shrinks as it heats up due to the infrared light from the halogen lamp 42, removing any slack. However, if all the slack in the dicing tape 3 is removed, it becomes too rigid, making it impossible to attach the expansion retaining ring 18 to the frame 4.

[0078] Here, let A be the amount of slack in the dicing tape 3 caused by expansion, and let B be the amount of slack in the dicing tape 3 required to be held in the expanded state by the expansion holding ring 18. If the amount of slack C, obtained by subtracting the amount of slack B from the amount of slack A, is removed by thermal shrinkage, the dicing tape 3 can be held in the expanded state by the expansion holding ring 18. However, if only the annular portion 3B of the dicing tape 3 is thermally shrunk, the amount of slack C cannot be removed, and the dicing tape 3 cannot be held in the expanded state even if the expansion holding ring 18 is attached to the frame 4.

[0079] Therefore, in the heating process of S150 shown in Figure 7, the slack amount C is removed by uniformly thermally shrinking the entire dicing tape 3. Specifically, since the dicing tape 3 in this embodiment is made of polyvinyl chloride, it tends to start thermal shrinking at approximately 60°C. For this reason, in the heating process of S150, when the radiation thermometer 50 measures that the temperature of the dicing tape 3 has reached 60°C, the control unit 48 in Figure 6 turns off the halogen lamp 42. As a result, the dicing tape 3 is gradually thermally shrunk by residual heat, and the slack amount C is removed when it returns to room temperature. This completes the heating process of S150. Note that the temperature at which the dicing tape 3 starts thermal shrinking differs depending on the material of the base material (polyester film, polyolefin film, and polyimide film), so the amount of infrared light emitted by the halogen lamp 42 and the timing of turning off the halogen lamp 42 should be controlled according to the material of the base material.

[0080] When the heating process in S150 is completed, the door 34 (see Figure 1) of the workroom 20 is opened, and the wafer unit 2 is transported from the heating chamber 30 to the workroom 20 through the opening 36 using a transport device (not shown). Then, the frame 4 of the wafer unit 2 is fixed to the fixing part 7 as shown in Figure 10(D).

[0081] Next, in the expanded state holding step S160 in Figure 7, as shown in Figure 10(E), the expanded holding ring 18 is raised from the standby position to the fitting position by the expanded holding ring moving mechanism 28, and the fitting portion 26 is fitted to the upper surface 4A of the frame 4 at the fitting position. As a result, the expanded state of the dicing tape 3 is held by the expanded holding ring 18. With this, the expanded state holding step S160 is completed.

[0082] As described above, the workpiece division method of the embodiment includes an expansion step of expanding the dicing tape 3, a heating step of applying heat to the entire dicing tape 3 to cause thermal shrinkage of the entire dicing tape 3, and an expansion state holding step of expanding the dicing tape 3 and maintaining the expanded state of the dicing tape 3. Therefore, the expanded state of the dicing tape 3 can be maintained by the expansion holding ring 18 while effectively removing the looseness caused by the plastic deformation of the dicing tape 3 that occurs after expansion.

[0083] Furthermore, as described above, the workpiece division method of this embodiment includes an expansion restriction step (S120) using the expansion restriction ring 17, which eliminates the problem of undivided lines on the division schedule that occurs when the chip size is small (1 mm).

[0084] As described above, the workpiece division method of this embodiment can effectively remove loosening caused by plastic deformation of the dicing tape 3 after expansion, while resolving the problem of undivided workpieces.

[0085] Although the above-described embodiment mentions an example using an expansion restricting ring 17, the present invention is not limited to this embodiment. In other words, even if the dicing tape 3 can be divided into individual chips 6 by a normal expansion operation without using an expansion restricting ring 17, the loosening of plastic deformation that occurs during expansion can be removed by the heating unit and heating process of the present invention.

[0086] Furthermore, although a halogen lamp 42 was exemplified as an example of the heating element of the present invention in the embodiment, the invention is not limited thereto. For example, a far-infrared lamp or an infrared lamp can be used instead of the halogen lamp 42.

[0087] Furthermore, although the halogen lamp 42 is configured in a rod shape as shown in Figure 5, its shape is not limited to a rod shape. For example, a ring-shaped halogen lamp can also be used. In this case, it is preferable to arrange multiple ring-shaped halogen lamps 42 of different diameters in concentric circles centered on the center of the dicing tape 3. This allows the entire dicing tape 3 to be heated uniformly. [Explanation of Symbols]

[0088] 1...Wafer, 2...Wafer unit, 3...Dicing tape, 3A...Central region, 3B...Annular region, 3C...Fixed region, 4...Frame, 5...Dividing line, 6...Chip, 7...Fixed part, 10...Workpiece dividing device, 12...Expansion section, 14...Heating section, 16...Expanding ring, 17...Expansion restricting ring, 18...Expansion holding ring, 20...Work chamber, 22...Expansion ring moving mechanism, 23...Expansion restricting ring moving mechanism, 24...Main ring, 26...Matching section, 28...Expansion holding ring moving mechanism, 30...Heating chamber, 32...Insulating wall, 34...Door, 36...Opening, 38...Table, 40...Radiant heat radiating member, 42...Halogen lamp, 44...Reflector, 46...Halogen lamp power supply, 48...Control unit, 50...Radiation thermometer

Claims

1. In a workpiece splitting device that splits a workpiece, which is attached to a dicing tape and mounted on a frame, into individual chips along a planned splitting line, An expanding ring for expanding the dicing tape, A heating unit that heats and shrinks the dicing tape by heating at least the area of ​​the dicing tape to which the workpiece is attached, An expansion retaining ring that holds the expanded state of the dicing tape that has been heat-shrunk by the heating unit, A workpiece splitting device equipped with the following features.

2. The heating unit is, A heating element that emits radiant heat, A heat reflecting member that reflects the radiant heat emitted from the heating member toward the dicing tape, A workpiece splitting apparatus according to claim 1, having the following features.

3. The heating element is a halogen lamp. The workpiece splitting apparatus according to claim 2.

4. In a workpiece division method in which a workpiece attached to dicing tape and mounted on a frame is divided into individual chips along a planned division line, An expansion step of expanding the dicing tape, A heating step in which the dicing tape is heat-shrinked by heating at least the area of ​​the dicing tape to which the workpiece is attached, An expanded state holding step is performed to maintain the expanded state of the dicing tape that has been heat-shrunk by the heating step, A workpiece division method comprising the following features.

5. The heating step involves applying radiant heat to the dicing tape. The workpiece division method according to claim 4.

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