Tape crimping device

Abstract

[Problem] To provide a tape crimping device that prevents wafer damage even when a tape with an attached ring frame is crimped onto the back of a wafer using a pressing roller. [Solution] The tape crimping device includes: an upper chamber; a lower chamber; a lifting mechanism that switches between a closed state and an open state, wherein the closed state is when the upper chamber descends and contacts the lower chamber, and the open state is when the upper chamber moves away from the lower chamber; a vacuum section that creates a vacuum in the upper and lower chambers in the closed state; and an atmospheric opening section that opens the upper and lower chambers to the atmosphere. A wafer stage is housed in the lower chamber. The wafer stage has a holding surface that supports only the remaining outer periphery of the wafer and includes a circular recess that sets the device area as non-contact. The tape crimping device includes: a positive pressure generating section that supplies air to the circular recess of the wafer stage, creating a positive pressure higher than the air pressure in the upper and lower chambers.

Description

[Technical Field]

[0001] The present invention relates to a tape pressing device for pressing tape that has been pressed onto an annular frame having an opening in the center for accommodating a wafer onto the back side of the wafer. [Previous Technology]

[0002] A wafer with a device area on the front side, in which multiple devices such as ICs and LSIs are divided by multiple intersecting dicing lines, and the remaining area around the device area, can be ground on the back side to form the desired thickness. Then, it can be divided into individual device chips by a dicing device or a laser processing device. The individual device chips can be used in electrical machines such as mobile phones and personal computers.

[0003] The applicant of this invention has proposed the following technical solution: In order to facilitate the transport of the ground wafer, after leaving the annular reinforcement on the back side corresponding to the remaining area of ​​the outer periphery and performing a predetermined processing, the cutting tape is pressed onto the back side of the wafer and the wafer is supported by an annular frame to remove the annular reinforcement from the wafer (see, for example, Patent Document 1).

[0004] However, in the technology disclosed in Patent Document 1, it is difficult to press the cutting tape onto the back of the wafer with an annular reinforcement formed on the outer periphery to form it as an integral part with the annular frame, and it is also difficult to cut the annular reinforcement to remove it from the wafer, resulting in poor productivity.

[0005] To solve this problem, the following approach can be considered: In the operation of attaching dicing tape to the back of the wafer to form an integral part with the annular frame, a wafer stage supporting the front side of the wafer is used. To prevent damage to the device areas formed on the front side of the wafer, the wafer stage should preferably only support the remaining peripheral area and have circular recesses that prevent contact with the device areas. (Prior art documents, patent documents)

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-62375 [Summary of the Invention]

[0007] Problem to be solved by the invention However, in a structure in which a wafer stage with a circular recess only supports the remaining area of ​​the outer periphery of the front side of the wafer, and a pressing roller presses the tape of the ring frame with tape attached to the back side of the wafer, there is a risk of damaging the wafer.

[0008] Accordingly, the object of the present invention is to provide a tape pressing device that can press the tape with the attached tape ring frame onto the back of the wafer using a pressing roller without damaging the wafer.

[0009] A means to solve the problem: According to the present invention, a tape pressing device is provided to press tape already pressed onto an annular frame having an opening in the center for accommodating a wafer onto the back side of the wafer. The tape pressing device includes: an upper chamber; a lower chamber accommodating a wafer stage, the wafer stage having a holding surface that supports only the remaining outer periphery of the wafer and includes a circular recess for setting the device area as non-contact; a lifting mechanism switching between a closed state and an open state, the closed state being a state in which the upper chamber descends and contacts the lower chamber, and the open state being a state in which the upper chamber leaves the lower chamber; and a vacuum section. In this closed state, the upper chamber and the lower chamber are formed into a vacuum; the atmospheric opening section opens the upper chamber and the lower chamber to the atmosphere; and the positive pressure generating component supplies air to the circular recess of the wafer stage and forms a positive pressure in the circular recess that is higher than the air pressure in the upper chamber and the lower chamber. With the tape of the attached annular frame positioned on the back of the wafer supported on the wafer stage, the lifting mechanism is activated to maintain the closed state and form a vacuum in the upper chamber and the lower chamber. The tape of the attached annular frame is pressed onto the back of the wafer by the pressing rollers provided in the upper chamber.

[0010] Ideally, the positive pressure generating component is activated when the pressing roller presses the wafer through the tape. Alternatively, an annular reinforcement can be formed in a convex shape on the back side of the wafer corresponding to the remaining area on the outer periphery.

[0011] Effects of the Invention The tape pressing device of the present invention includes a positive pressure generating component that supplies air to the wafer stage and forms a positive pressure higher than the air pressure in the upper and lower chambers. Therefore, even if the tape with tape attached to the ring frame is pressed onto the back of the wafer by pressing rollers, the wafer will not be damaged.

Implementation Method

[0013] The following describes the tape pressing device according to an embodiment of the present invention with reference to the drawings.

[0014] (Tape crimping device 2) As shown in FIG1, the tape crimping device 2 includes: an upper chamber 4; a lower chamber 6; a lifting mechanism 8 for switching between a closed state and an open state, wherein the closed state is such that the upper chamber 4 descends and contacts the lower chamber 6, and the open state is such that the upper chamber 4 leaves the lower chamber 6; a vacuum section 10 for creating a vacuum in the upper chamber 4 and the lower chamber 6 in the closed state; and an atmosphere opening section 12 for opening the upper chamber 4 and the lower chamber 6 to the atmosphere.

[0015] (Upper Chamber 4) The upper chamber 4 includes a circular top plate 14 and a cylindrical side wall 16 hanging from the periphery of the top plate 14, and the lower part of the side wall 16 is open. Referring to Figures 2 and 3, a pressing roller 18, a support plate 20 and an X-axis feed mechanism 22 (refer to Figure 2) are arranged in the accommodating space defined by the lower surface of the top plate 14 and the inner peripheral surface of the side wall 16. The pressing roller 18 is used to press the tape of the annular frame with tape attached onto the wafer. The support plate 20 rotatably supports the pressing roller 18. The X-axis feed mechanism 22 moves the support plate 20 in the X-axis direction indicated by arrow X in Figure 2.

[0016] As shown in Figure 2, the X-axis feed mechanism 22 has a ball screw 24 and a motor 26. The ball screw 24 is connected to the support plate 20 and extends in the X-axis direction. The motor 26 rotates the ball screw 24. Furthermore, the X-axis feed mechanism 22 converts the rotational motion of the motor 26 into linear motion through the ball screw 24 and transmits it to the support plate 20, causing the pressing roller 18 and the support plate 20 to move together along a pair of guide rails 28 extending in the X-axis direction.

[0017] (Lower Chamber 6) As shown in Figures 2 and 3, the lower chamber 6 has a cylindrical sidewall 30. The upper part of the sidewall 30 is open, and the lower part of the sidewall 30 is closed. A wafer stage 32 for holding the wafer and an annular frame is housed inside the sidewall 30.

[0018] The wafer stage 32 has a holding surface 34, which holds only the remaining peripheral area of ​​the wafer and is formed in a concave shape to make the device area non-contact. The holding surface 34 has an annular holding portion 36 and a circular recess 38. The annular holding portion 36 holds the remaining peripheral area of ​​the wafer and the annular frame, and the circular recess 38 corresponds to the device area. In the annular holding portion 36, a rubber ring 40 is arranged along the periphery of the circular recess 38. In the rubber ring 40, a plurality of suction holes 40a are provided at intervals in the circumferential direction. Each suction hole 40a is connected to the suction source 44 through the flow path 42 (see Figure 2).

[0019] (Lifting mechanism 8, vacuum section 10, atmospheric opening section 12) The lifting mechanism 8 can be constructed by a suitable actuator such as a cylinder installed on the upper surface of the top plate 14 of the upper chamber 4. The vacuum section 10 can be constructed by a suitable vacuum pump. The vacuum section 10 is connected to the lower chamber 6 through the flow path 46. Furthermore, an atmospheric opening section 12 is provided in the flow path 46, and the aforementioned atmospheric opening section 12 includes a suitable valve that can open the flow path 46 to the atmosphere.

[0020] (Positive Pressure Generation Component 48) Referring to Figures 2 and 3, the tape pressing device 2 of this embodiment includes a positive pressure generation component 48. The positive pressure generation component 48 supplies air to a concave region (circular recess 38) of the wafer stage 32, creating a positive pressure higher than the air pressure in the upper chamber 4 and the lower chamber 6. The positive pressure generation component 48 has a supply hole 50 and an air supply source 54 (refer to Figure 2). The supply hole 50 is formed in the circular recess 38, and the air supply source 54 is connected to the supply hole 50 through a flow path 52.

[0021] (Wafer W) Figure 4(a) shows a circular wafer W, which is pressed onto a tape attached to an annular frame by a tape pressing device 2. The wafer W can be formed from a suitable semiconductor material such as silicon (Si) or silicon carbide (SiC). The front side Wa of the wafer W has a circular device region Rd and a peripheral remaining region Rs surrounding the device region Rd. The device region Rd is divided into a plurality of rectangular regions by a grid-like dicing S, and devices D such as ICs and LSIs are formed in each of the plurality of rectangular regions. In addition, although the boundary B between the device region Rd and the peripheral remaining region Rs is represented by a two-point chain line for convenience, the line representing the boundary B does not actually exist.

[0022] In the wafer W shown in FIG4(a), an annular reinforcement R is formed in a convex shape on the back surface Wb corresponding to the peripheral residual region Rs. Therefore, the thickness of the peripheral residual region Rs is greater than the thickness of the device region Rd.

[0023] Furthermore, the wafer pressed onto the tape of the annular frame by the tape pressing device 2 can also be a wafer W' as shown in FIG4(b), where the annular reinforcing portion is not provided on the back side Wb'. In addition, the following description mainly focuses on the case of pressing the tape onto a wafer W having a reinforcing portion R.

[0024] (Ring frame FT with adhesive tape) Figure 5 shows a ring frame FT with adhesive tape for pressing the aforementioned wafer W. The ring frame FT with adhesive tape includes: a ring frame F having an opening Fo for accommodating the wafer W; and a circular adhesive tape T pressed onto the ring frame F.

[0025] Next, the operation of the tape crimping device 2 as described above will be explained.

[0026] In this embodiment, the lifting mechanism 8 is first activated to open the upper chamber 4 from the lower chamber 6. Next, as shown in FIG2, with the front side Wa where the device D is formed facing downwards, the wafer W is placed on the holding surface 34 of the wafer stage 32.

[0027] When placing the wafer W on the holding surface 34, the remaining peripheral area Rs of the wafer W is positioned on the rubber ring 40 of the annular holding portion 36, and the device area Rd of the wafer W is positioned on the circular recess 38. Therefore, even when the front side Wa with the device D is facing downwards, placing the wafer W on the holding surface 34 of the wafer stage 32 will prevent the device D in the device area Rd from contacting the holding surface 34, thus preventing damage to the device D.

[0028] Next, the attraction source 44 is activated, generating an attraction force in each attraction hole 40a of the rubber ring 40 to attract and hold the remaining peripheral region Rs of the wafer W. At this time, the pressure of the attraction hole 40a should be, for example, an absolute pressure of about 100 Pa.

[0029] After the wafer W is attracted and held on the wafer stage 32, the annular frame FT with adhesive tape is placed on the annular holding part 36 of the wafer stage 32 (see Figure 2). At this time, the adhesive tape T of the annular frame FT with adhesive tape is positioned on the back side Wb of the wafer W which is supported on the wafer stage 32, and the adhesive side of the adhesive tape T is facing downwards, so that the adhesive side of the adhesive tape T is facing the back side Wb of the wafer W.

[0030] After the annular frame FT with adhesive tape is placed on the wafer stage 32, the upper chamber 4 is lowered by the lifting mechanism 8, and the lower end of the side wall 16 of the upper chamber 4 contacts the upper end of the side wall 30 of the lower chamber 6 (see Figure 3). This closes the upper chamber 4 and the lower chamber 6. As shown in Figure 6, the pressing roller 18 contacts the annular frame FT with adhesive tape, and the adhesive surface of the tape T contacts the upper end of the reinforcing portion R of the wafer W.

[0031] Next, with the atmospheric opening 12 closed, the vacuum section 10 is activated to create a vacuum inside the upper chamber 4 and the lower chamber 6. However, the pressure inside the upper chamber 4 and the lower chamber 6 is greater than the pressure inside the suction port 40a (for example, an absolute pressure of about 200 Pa). As a result, the force attracting the wafer W will be slightly weakened, but even with the upper chamber 4 and the lower chamber 6 created as a vacuum, the state in which the wafer W is attracted and held by the wafer stage 32 can still be maintained.

[0032] Next, as shown in Figures 6 and 7, the pressing roller 18, which is installed in the upper chamber 4, is rolled in the X-axis direction by the X-axis feed mechanism 22, and the pressing roller 18 presses the tape T of the annular frame FT with tape attached to the back surface Wb of the wafer W. At this time, the pressing roller 18 will press the wafer W downward through the tape T. As a result, since only the outer peripheral area Rs of the wafer W is supported by the rubber ring 40 of the annular holding part 36, and the device area Rd has been positioned in the circular recess 38, there is a risk that the pressing roller 18 may cause the wafer W to bend downward, resulting in damage to the wafer W.

[0033] However, the tape crimping device 2 of this embodiment has a positive pressure generating component 48 that supplies air to the circular recess 38 to form a positive pressure higher than the air pressure of the upper chamber 4 and the lower chamber 6. Therefore, it can prevent the wafer W from being bent due to the pressing of the pressing roller 18, which would lead to the wafer W being damaged.

[0034] Specifically, when the pressing roller 18 presses the wafer W through the tape T, the air supply source 54 of the positive pressure generating component 48 is activated, supplying air from the supply hole 50 to the circular recess 38, and forming the circular recess 38 with a positive pressure higher than that of the upper chamber 4 and the lower chamber 6. At this time, the air pressure of the circular recess 38 is set to be slightly higher than that of the upper chamber 4 and the lower chamber 6, and high enough to suppress the bending of the wafer W due to the pressing of the pressing roller 18. For example, when the air pressure of the upper chamber 4 and the lower chamber 6 is about 200 Pa, the air pressure of the circular recess 38 is preferably about 300 Pa.

[0035] Thus, in the tape crimping device 2 of this embodiment, since the circular recess 38 is formed to a higher positive pressure than the upper chamber 4 and the lower chamber 6 by the positive pressure generating component 48, when the wafer W is pressed by the pressing roller 18 through the tape T, the bending of the wafer W can be suppressed, and the damage of the wafer W can be prevented.

[0036] When the tape T is pressed onto the wafer W by the pressing roller 18, if the interior of the upper chamber 4 and the lower chamber 6 is made into a vacuum, as described above, the attractive force of the wafer W generated by the wafer stage 32 will be weakened. However, in this embodiment, since the remaining peripheral area Rs of the wafer W is positioned in the rubber ring 40 of the annular holding portion 36, when the tape T is pressed onto the wafer W by the pressing roller 18, the position of the wafer W can be prevented from shifting by the friction between the rubber ring 40 and the wafer W.

[0037] In this embodiment, since an annular reinforcing portion R is formed on the back side Wb of the wafer W, even if the tape T is pressed onto the back side Wb of the wafer W by the pressing roller 18, sometimes a portion of the tape T is not tightly adhered to the root of the annular reinforcing portion R.

[0038] Regarding this point, in this embodiment, the tape T is pressed onto the wafer W by the pressing roller 18 while the upper chamber 4 and the lower chamber 6 are in a vacuum state. Therefore, if the atmospheric opening 12 is opened after the pressing roller 18 is moved, the tape T can be pressed by atmospheric pressure, so that the tape T is tightly adhered to the wafer W along the root of the reinforcing part R.

[0039] Furthermore, although the case where tape T is an adhesive tape has been described in this embodiment, tape T may also be a thermosetting tape without an adhesive layer laid on the sheet. The thermosetting tape is a tape of thermoplastic synthetic resin (e.g., polyolefin resin), and is a tape that softens or melts and exerts adhesive force when heated to a temperature near its melting point.

[0040] When the tape T is a heat-pressed tape, the tape T can be heat-pressed onto the back side Wb of the wafer W by heating at least one of the pressing roller 18 or the wafer stage 32 to a temperature at which the tape T softens or melts. [Simplified Explanation of the Diagram]

[0012] FIG1 is a perspective view of the tape crimping device according to an embodiment of the present invention. FIG2 is an exploded perspective view of the tape crimping device shown in FIG1. ​​FIG3 is a cross-sectional view of the tape crimping device shown in FIG1. ​​FIG4(a) is a perspective view of a wafer with a reinforcing portion, and (b) is a perspective view of a wafer without a reinforcing portion. FIG5 is a perspective view of the annular frame with tape attached. FIG6 is a schematic cross-sectional view showing the state of starting tape pressing. FIG7 is a schematic cross-sectional view showing the state of ending tape pressing.

Claims

1. A tape pressing device for pressing tape already pressed onto an annular frame having a central opening for accommodating a wafer onto the back side of the wafer, the tape pressing device comprising: an upper chamber; a lower chamber accommodating a wafer stage, the wafer stage having a holding surface supporting only the remaining peripheral area of ​​the wafer and including a circular recess for non-contact device areas; a lifting mechanism switching between a closed state and an open state, the closed state being a state in which the upper chamber descends to contact the lower chamber, and the open state being a state in which the upper chamber moves away from the lower chamber; a vacuum section for creating a vacuum in the upper chamber and the lower chamber in the closed state; an atmospheric opening section for opening the upper chamber and the lower chamber to the atmosphere; and a positive pressure generating component for supplying air to the circular recess of the wafer stage and creating a positive pressure in the circular recess that is higher than the air pressure in the upper chamber and the lower chamber. With the tape of the annular frame already positioned on the back of the wafer supported on the wafer stage, the lifting mechanism is activated to maintain the closed state and create a vacuum in the upper and lower chambers. The pressing rollers, which are installed in the upper chamber, press the tape of the annular frame onto the back of the wafer. When the lifting mechanism is activated to create a closed state, the pressing rollers contact the annular frame with the tape, and the pressing rollers are rotated to press the tape of the annular frame onto the back of the wafer, the positive pressure generating component is activated when the pressing rollers press the wafer through the tape.

2. A tape pressing device for pressing tape already pressed onto an annular frame having a central opening for accommodating a wafer onto the back side of the wafer, the tape pressing device comprising: an upper chamber; a lower chamber accommodating a wafer stage, the wafer stage having a holding surface supporting only the remaining peripheral area of ​​the wafer and including a circular recess for non-contact device areas; a lifting mechanism switching between a closed state and an open state, the closed state being a state in which the upper chamber descends to contact the lower chamber, and the open state being a state in which the upper chamber moves away from the lower chamber; a vacuum section for reducing the pressure in the upper and lower chambers in the closed state; an atmospheric opening section for opening the upper and lower chambers to the atmosphere; and a positive pressure generating component for supplying air to the circular recess of the wafer stage and forming a positive pressure in the circular recess that is higher than the air pressure in the upper and lower chambers. The holding surface of the wafer stage has an annular member arranged along the periphery of the circular recess and attracting and holding the remaining outer periphery of the wafer. With the tape of the annular frame with adhesive tape positioned on the back of the wafer supported on the wafer stage, the lifting mechanism is activated to maintain the closed state and reduce the pressure in the upper and lower chambers to a level where the attraction and holding of the wafer by the annular member will be maintained. The tape of the annular frame with adhesive tape is pressed onto the back of the wafer by a pressing roller arranged in the upper chamber.

3. The tape pressing device of claim 2, wherein the positive pressure generating component is activated when the pressing roller presses the wafer across the tape.

4. The tape bonding apparatus of claim 1 or 2, wherein an annular reinforcement is formed convexly on the back side of the wafer corresponding to the remaining area of ​​the outer periphery.

5. The tape crimping device as claimed in claim 2, wherein the annular member is made of rubber.

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