JP4637692B2 - Adhesive film sticking device - Google Patents

Description

  According to the present invention, a device region in which a plurality of devices are formed on the front surface of a wafer and an outer peripheral surplus region surrounding the device region are formed, and a back surface corresponding to the device region is compared with a back surface of the outer peripheral surplus region. The present invention relates to a pressure-sensitive adhesive film sticking apparatus for sticking a pressure-sensitive adhesive film for die bonding to a back surface of a wafer processed into a concave shape by forming a ring-shaped reinforcing portion on the back surface of the outer peripheral surplus region.

  Conventionally, a wafer on which a plurality of devices such as ICs and LSIs are formed is divided into individual devices by a dividing device such as a dicing device, and is used for electrical equipment such as a mobile phone and a personal computer. Here, in order to reduce the weight and size of electrical equipment, the thickness of the wafer is thinly processed to be 50 μm or less and 30 μm or more. However, since this thin wafer is difficult to handle, Only the back surface of the device region in which the device is formed is thinly ground, and a ring-shaped reinforcing portion is left in the outer peripheral surplus region surrounding the device region to facilitate handling of the thinned wafer (see Patent Document 1). ).

  Then, before the wafer is divided into individual devices, DAF (die attach film), which is a die-bonding adhesive film, is disposed on the back surface, and after the wafer is divided into individual devices, the wafer is die-bonded to a lead frame or the like. Is done.

JP-A-5-121384

  However, when the DAF is adhered to the back surface of the wafer whose back surface is processed into a concave shape, the ring-shaped reinforcing portion is in the way and the DAF is not easily bonded. There is a problem in that there are cases where reliable adhesion cannot be performed due to air or the like interposed therebetween.

  This invention is made in view of the above, and provides the adhesive film sticking apparatus which can adhere | attach DAF on the back surface of the wafer by which the back surface was processed into the concave shape, and can adhere easily and reliably. With the goal.

In order to solve the above-described problems and achieve the object, an adhesive film sticking apparatus according to the present invention includes a device region in which a plurality of devices are formed on the surface of a wafer, and an outer peripheral surplus region surrounding the device region. Formed on the back surface of the wafer, the back surface corresponding to the device region is processed to be thinner than the back surface of the outer periphery surplus region, and a ring-shaped reinforcement is formed on the back surface of the outer periphery surplus region. An adhesive film adhering apparatus for adhering an adhesive film for die bonding, the wafer holding means for holding the wafer, the adhesive film holding means for holding the adhesive film, the wafer holding means, and the adhesive film holding means accommodating the door, surrounded to be sealed with the inner wall of the vacuum chamber of the wafer holding means and the adhesive film holding means and the cylindrical A vacuum chamber that forms a space and depressurizes the space, a back surface corresponding to a device region of the wafer held by the wafer holding means in the vacuum chamber, and an adhesive film held by the adhesive film holding means are approached And a controller that presses the space between the wafer and the pressure-sensitive adhesive film while reducing the pressure, and attaches the pressure-sensitive adhesive film to the back surface corresponding to the device region of the wafer.

  Further, in the above invention, the pressure-sensitive adhesive film sticking apparatus according to claim 2 is such that the diameter of the holding surface of the pressure-sensitive adhesive film holding means is smaller than the inner diameter of the ring-shaped reinforcing portion formed on the back surface of the wafer, And the holding surface of the said adhesive film holding means respond | corresponds to the said device area | region.

  In the adhesive film sticking apparatus according to the present invention, the control means causes the back surface corresponding to the device region of the wafer held by the wafer holding means in the decompression chamber and the adhesive film held by the adhesive film holding means to approach, Since the space between the wafer and the adhesive film that are close to each other is pressed while reducing the pressure, and the adhesive film is attached to the back surface corresponding to the device region of the wafer, the wafer whose back surface is processed into a concave shape As a result, the DAF can be easily adhered to the back surface, and the sticking can be reliably performed.

  Hereinafter, an adhesive film sticking apparatus which is the best mode for carrying out the present invention will be described with reference to the drawings.

  First, processing of a wafer that is an object to which an adhesive film is attached will be described. The surface Wa of the wafer W shown in FIG. 1 has a device region W1 and an outer peripheral surplus region W2. A plurality of devices D partitioned by streets S are formed in the device region W1, and an outer peripheral surplus region W2 in which no device D is formed is formed on the outer peripheral side of the device region W1. This device region W1 is surrounded by the outer peripheral surplus region W2. When the back surface Wb of the wafer W is polished on the front surface Wa of the wafer W, a protective member 1 such as a tape is attached to protect the device D as shown in FIG.

  Thereafter, the portion corresponding to the device region W1 in the back surface Wb of the wafer W, that is, the back side of the device region 1 is ground to a desired thickness. For this grinding, for example, a grinding device 2 shown in FIG. 3 can be used.

  The grinding apparatus 2 includes a chuck table 20 that holds a wafer, and a grinding unit 21 that performs grinding on the wafer held on the chuck table 20. The grinding unit 21 includes a rotary shaft 22 having a vertical axis, a wheel 23 attached to the lower end of the rotary shaft 22, and a grindstone portion 24 fixed to the lower surface of the wheel 23. The wafer W is in a state where the protective member 1 side is held by the chuck table 20 and the back surface Wb is exposed. As the chuck table 20 rotates and the wheel 23 rotates, the grinding unit 21 descends, so that the rotating grindstone unit 24 comes into contact with the back surface Wb of the wafer W to perform grinding. At this time, the grindstone portion 24 is brought into contact with the back side of the device region W1 formed on the surface Wa of the wafer W so that the outer peripheral side thereof is not ground. When the desired amount of the back side of the device region W1 is ground, the grinding is finished. In this way, by grinding only the portion corresponding to the device region W1 in the back surface Wb, as shown in FIGS. 4 and 5, a recess W3 is formed in the back surface Wb, corresponding to the outer peripheral surplus region W2. The ring-shaped reinforcing portion W4 having the same thickness as that before grinding remains in the portion. For example, the width of the ring-shaped reinforcing portion W4 may be about 2 to 3 mm. Further, it is desirable that the thickness of the ring-shaped reinforcing portion W4 is several hundred μm. On the other hand, the thickness of the device region W1 can be reduced to about 30 μm.

  Here, the concave wafer W having the ring-shaped reinforcing portion W4 is bonded to the concave portion corresponding to the device region W1 on the back surface Wb by using the adhesive film sticking apparatus 3 shown in FIG. Processing to wear is performed.

  As shown in FIG. 6, the adhesive film sticking apparatus 3 moves up and down to hold the wafer W by a vacuum suction force, and moves up and down to hold the DAF 36 by a vacuum suction force. A space sandwiched between the part 32, the wafer holding part 31 and the DAF holding part 32 is formed, and the decompression chamber 33 for vacuum-sucking the space, the wafer holding part 31, the DAF holding part 32, and the decompression chamber 33 are retained. And an apparatus main body 30 that controls each part.

  The wafer holding unit 31 and the DAF holding unit 32 have disk-shaped chuck tables 34 and 35 via the arms 31 a and 32 a, respectively, with respect to the apparatus main body 30, and the chuck tables 34 and 35 are directed toward the decompression chamber 33. Are arranged at opposite positions. The decompression chamber 33 has a cylindrical shape, and its inner diameter substantially matches the outer diameter of the chuck tables 34 and 35. When the chuck tables 34 and 35 are inserted into the decompression chamber 33, they are sandwiched between the chuck tables 34 and 35. The sealed space is sealed. On the other hand, a vacuum hole 33 a that communicates between the inside of the decompression chamber 33 and the apparatus main body 30 is provided at the center of the side surface of the decompression chamber 33, and the vacuum hole 33 a is a decompression chamber holding portion that holds the decompression chamber 33 fixedly. 33b.

  The apparatus main body 30 includes an elevating drive control unit 30a that controls the elevating drive of the wafer holding unit 31 and the DAF holding unit 32, a pump unit 30b that performs vacuum suction with respect to the chuck tables 34 and 35 and the decompression chamber 33, and an elevating drive. It has the control part 30c which controls the control part 30a and the pump part 30b. The wafer holding unit 31 and the DAF holding unit 32 rotate the pinion gears 31c and 32c when the rack gears 31b and 32b attached in the vertical direction of the arms 31a and 32a mesh with the pinion gears 31c and 32c attached to the motor. Motion is converted to linear motion. The means for raising and lowering the wafer holding unit 31 and the DAF holding unit 32 is not limited to this and may be driven using a ball screw or the like.

  Here, with reference to FIG. 6 and FIG. 7, attachment of the wafer W and DAF 36 with respect to the adhesive film sticking apparatus 3 is demonstrated. As shown in FIG. 7, the wafer W is attached to the chuck table 34 with the surface Wa side facing the lower surface of the chuck table 34. Although the protective member 1 is not shown in FIG. 7, the protective member 1 is attached to the surface Wa as shown in FIG. Therefore, the wafer W is attached to the chuck table 34 via the protective member 1 by vacuum suction. On the other hand, the DAF 36 is attached to the chuck table 35 with the release paper 36 a attached to the entire surface of one side thereof, and the release paper 36 a facing the upper surface of the holding surface 35 a of the chuck table 35. Accordingly, the DAF 36 is attached to the holding surface 35a of the chuck table 35 via the release paper 36a.

  The operation of adhering the DAF 36 to the concave portion of the wafer W using the adhesive film adhering apparatus 3 will be described. First, the chuck table 34 is lowered while the wafer W and the DAF 36 are attached to the chuck tables 34 and 35, respectively. The chuck table 35 is raised and the chuck tables 34 and 35 are inserted into the decompression chamber 33, and the chuck table 34 and the chuck table 35 are brought close to each other while being guided. Thereafter, when the distance d between the wafer W on the chuck table 34 and the DAF 36 on the chuck table 35 reaches a predetermined distance d1, the space formed by the wafer W, the DAF 36, and the decompression chamber 33 through the vacuum hole 33a. Adhering is performed by pressing the wafer W and the DAF 36 while reducing the pressure of E. The predetermined distance d1 is, for example, 0.5 mm to 1.0 mm. Further, the vacuum hole 33a communicates with the space E formed at the predetermined distance d1. By performing such adhesion, air or the like does not intervene between the bottom surface of the concave portion of the wafer W and the DAF 36, so that reliable adhesion can be performed.

  Here, the sticking control process by the control unit 30c will be described based on the time chart shown in FIG. First, the controller 30c vacuum-sucks the wafer W and the DAF 36 to the chuck tables 34 and 35 with the force of the suction force F1, respectively. On the other hand, the decompression chamber 33 is open to the atmosphere, and the value of the suction force F2 is zero.

  Thereafter, the control unit 30c increases the suction force to the decompression chamber 33 to F3 at the time t1 when the distance d reaches the predetermined distance d1. At this time, the suction force F3 is equal to the suction force F1 and is in a vacuum state. Further, the distance d is further reduced, and the wafer W and the DAF 36 are securely attached to each other by the pressing of the wafer holding units 31 and the DAF holding unit 32. In particular, since the space E is depressurized to be in a vacuum state, air that may be present on the bonding surface between the wafer W and the DAF 36 is reliably removed, and reliable bonding can be performed. If the suction force of F1 is the same as the suction force of F3, the wafer W falls off from the chuck table 34, but there is no problem because the distance d is as small as 0.5 mm to 1.0 mm.

  Thereafter, at time t2, the control unit 30c reduces the suction force of the decompression chamber 33 from F3 to F2, and lowers one suction force of the chuck tables 34 and 35 from F1 to F2, so that the chucking force is F1. The wafer W to which the DAF 36 is attached is held on either the table 34 or 35 by vacuum suction. Thereafter, the control unit 30c gradually increases the distance d to separate them, and returns the chuck tables 34 and 35 to the initial positions where the wafer W and the DAF 36 are attached.

  In this way, as shown in FIG. 9, a wafer W is obtained in which the DAF 36 is securely attached to the recess formed on the back surface of the wafer W. The protective member 1 is still attached to the surface of the wafer W, and the release paper 36a is still attached to the surface of the DAF 36.

  Thereafter, dicing of the wafer W to which the DAF 36 is attached is performed. First, as shown in FIG. 10, the protective member 1 attached to the surface of the wafer W is peeled off, and the release paper 36 a of the DAF 36 is peeled off. Thereafter, as shown in FIG. 11, the wafer W is adhered to the dicing tape T, the wafer W is supported by the dicing frame F via the dicing tape T, and the back surface (DAF 36) is exposed. Become.

  The wafer W supported by the dicing frame F is diced by cutting along the streets S formed on the surface Wa, and divided into devices D. Although this dicing is also realized by irradiating the street S with laser light, here, for example, a case where the street S is cut using the cutting device 4 shown in FIG. 12 will be described.

  The cutting device 4 includes a chuck table 40 that holds the wafer W, a frame clamp 40 a that supports a dicing frame F that supports the wafer W, and a cutting unit 41 that acts on the wafer W held on the chuck table 40 to perform cutting. And have. The chuck table 40 is connected to a drive source 400 and is rotatable. The drive source 400 is fixed to the moving base 401, and the moving base 401 can be moved in the X-axis direction by the cutting feed unit 42. The cutting feed unit 42 includes a ball screw 420 arranged in the X-axis direction, a pulse motor 421 connected to one end of the ball screw 420, and a pair of guide rails 422 arranged in parallel with the ball screw 420. A nut (not shown) provided at the lower part of the movable base 401 is screwed into the nut. The ball screw 420 is driven and rotated by the pulse motor 421, and accordingly, the moving base 401 is guided by the guide rail 422 and moves in the X-axis direction.

  In the cutting part 41, a cutting blade 412 is attached to the tip of a spindle 411 that is rotatably supported by a housing 410, and the housing 410 is supported by a support part 413.

  An alignment portion 43 that detects the street S of the wafer W is fixed to the side portion of the housing 410. The alignment unit 43 includes an infrared camera 430 that images from the back surface of the wafer W and images the front surface of the wafer W. Based on the image acquired by the infrared camera 430, pattern matching with a prestored key pattern is performed. The street S to be cut is detected by a process such as the above.

  The cutting part 41 and the alignment part 43 can be moved in the Z-axis direction by a cutting feed part 44. The incision feeding portion 44 includes a ball screw 441 arranged in the Z-axis direction on one surface of the wall portion 440, a pulse motor 442 that rotates the ball screw 441, and a guide rail 443 arranged in parallel with the ball screw 441. And a nut (not shown) inside the support portion 413 is screwed into the ball screw 441. The support unit 413 is driven by the pulse motor 442 and is guided by the guide rail 443 as the ball screw 441 rotates, and moves up and down in the Z-axis direction. The cutting unit 41 supported by the support unit 413 also moves in the Z-axis direction. It is configured to move up and down.

  The cutting unit 4 is movable in the Y-axis direction by an index feeding unit 45. The index feeding section 45 is formed integrally with a ball screw 450 arranged in the Y-axis direction, a wall section 440, a moving base 451 in which an internal nut is screwed to the ball screw 450, and a pulse motor that rotates the ball screw 450. 452 and a guide rail 453 arranged in parallel with the ball screw 450, and a nut (not shown) inside the moving base 451 is screwed into the ball screw 450. The moving base 451 is driven by the pulse motor 452 and is guided by the guide rail 453 as the ball screw 450 is rotated, and moves in the Y-axis direction. In accordance with this, the cutting unit 41 also moves in the Y-axis direction. It has a configuration.

  The wafer W supported by the dicing frame F via the dicing tape T is sucked and held by the chuck table 40 with the back side Wb exposed, that is, the side where the DAF 36 is exposed. Then, when the chuck table 40 moves in the + X direction, the wafer W is positioned directly below the infrared camera 430, and the surface Wa of the wafer W is imaged by the infrared camera 430 through the wafer W, and based on the image. The alignment unit 43 detects the street S and aligns the street S with the cutting blade 412 in the Y-axis direction.

  Further, the chuck table 40 is moved in the + X-axis direction by the cutting feed portion 42 and the cutting portion 41 is lowered by the cutting feed portion 44 while rotating the cutting blade 412 at a high speed, and the cutting blade 41 is directed toward the detected street S. 412 is cut and this street S is cut.

  The same cutting is sequentially performed while the cutting section 41 is indexed and fed at intervals of the streets S by the index feeding section 45, and after all the streets S in the same direction are cut, the same cutting is performed while rotating the chuck table 40 by 90 degrees. , The wafer W is divided into individual devices D. When cutting each street S, if the ring-shaped reinforcing portion W4 on the extended line of the street S is also cut, it is not necessary to remove the ring-shaped reinforcing portion W4 later.

  Before dividing each device, the inner side of the ring-shaped reinforcing portion W4 may be cut slightly along the inner periphery to remove the ring-shaped reinforcing portion W4 as shown in FIG. The removal of the ring-shaped reinforcing portion W4 is realized, for example, by cutting along the inner periphery of the ring-shaped reinforcing portion W4 while rotating the wafer W supported by the dicing frame F via the dicing tape T. . When the ring-shaped reinforcing portion W4 is removed, the wafer W with the DAF 36 attached to the upper surface remains on the dicing frame F via the dicing tape T. If the ring-shaped reinforcing portion W4 is removed before dividing each device D in this way, only the device region W1 needs to be cut when each device D is divided, and there is no need to cut the ring-shaped reinforcing portion W4. Therefore, the moving stroke of the chuck table 40 that holds the wafer W can be shortened.

  In the above-described division processing, the case where dicing is performed from the back surface side of the wafer W has been described. However, the present invention is not limited to this, and dicing may be performed from the front surface side. In this case, a dicing tape having a convex portion corresponding to the concave portion on the back surface may be provided. This convex part supplements the depth to DAF36 already stuck. When the wafer W is diced from the back side by the cutting device 4, the wafer W is in a state where the surface Wa on which the streets S are formed is exposed, so the camera used for imaging during alignment needs to be an infrared camera. There is no. Further, the ring-shaped reinforcing portion W4 may be removed before dicing.

  In the above-described embodiment, the wafer W and the DAF 36 are held using the chuck tables 34 and 35 by vacuum suction. However, the present invention is not limited to this, and the wafer W is held by an electrostatic chuck table using electrostatic force. And DAF 36 may be held.

  Further, after being processed into the wafer W shown in FIG. 4 and FIG. 5, a conductive film such as a metal is formed on the back surface of the wafer W, the conductive film is grounded, and each device D is tested. You may make it stick the DAF36 mentioned above to the recessed part of this back surface.

  Furthermore, a method of forming a concave portion in a region corresponding to the device region W1 on the back surface of the wafer W and forming a ring-shaped reinforcing portion W4 including an outer peripheral surplus region on the outer peripheral side of the concave portion is a grinding process performed by the grinding apparatus 2. For example, a portion of the back surface of the wafer W other than the concave portion to be formed is masked, and the unmasked portion is subjected to plasma etching with a fluorine-based gas, or wet etching is performed with a fluorine-based etching solution. By doing so, the concave portion may be formed to form the ring-shaped reinforcing portion W4, or the concave portion may be formed by CMP to form the ring-shaped reinforcing portion W4.

  Moreover, although the control unit 30c described above changes the suction force of the chuck tables 34 and 35 and the decompression chamber 33 abruptly at time points t1 and t2, the suction force may be gradually changed.

It is a perspective view which shows the wafer and protection member of a process target. It is a perspective view which shows the state by which the protection member was stuck on the surface of the wafer. It is a perspective view which shows the state which forms the recessed part of a wafer using a cutting device. It is the perspective view which looked at the wafer in which the recessed part and the ring-shaped reinforcement part were formed from the back surface side. It is sectional drawing of the wafer in which the recessed part and the ring-shaped reinforcement part were formed. It is a schematic diagram which shows the structure of the adhesive film sticking apparatus which is embodiment of this invention. It is a perspective view explaining the arrangement | positioning relationship of a wafer holding part and a wafer, a decompression chamber, and a DAF holding part and DAF. Time indicating the time change of the distance between the wafer held by the wafer holding unit and the DAF held by the DAF holding unit, the suction force of each chuck table of the wafer holding unit and the DAF holding unit, and the suction force of the decompression chamber It is a sequence diagram. It is sectional drawing which shows the structure of the wafer in which DAF was stuck by the adhesive film sticking apparatus. It is a perspective view which shows the state which peels a protection member from the wafer shown in FIG. FIG. 11 is a perspective view showing a state where the wafer shown in FIG. 10 is supported by a dicing frame via a dicing tape. It is a perspective view which shows the structure of the cutting device which dices a wafer. It is a perspective view which shows the state which removes a ring-shaped reinforcement part from a wafer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Protective member 2 Grinding device 3 Workpiece carry-in / carry-in mechanism 4 Cutting device 20, 34, 35 Chuck table 21 Grinding part 22 Rotating shaft 23 Wheel 24 Grinding wheel part 30 Apparatus main body part 30a Lift drive control part 30b Pump part 30c Control part 31 Wafer holding part 31a, 32a Arm 31b, 32b Rack gear 31c, 32c Pinion gear 32 DAF holding part 33 Depressurization chamber 33a Vacuum hole 33b Depressurization chamber holding part 36 DAF
36a Release paper 40 Chuck table 40a Frame clamp 41 Cutting part 42 Cutting feed part 43 Alignment part 44 Cutting feed part 45 Indexing feed part 400 Drive source 401,451 Moving base 410 Housing 411 Spindle 412 Cutting blade 413 Support part 420,441 450 Ball screw 421, 442, 452 Pulse motor 422, 443, 453 Guide rail 430 Infrared camera 440 Wall W Wafer Wa Front Wb Back W1 Device area W2 Peripheral surplus area W3 Recess W4 Ring-shaped reinforcement S Street D Device F Dicing frame T Dicing tape

Claims (2)

A device region in which a plurality of devices are formed on the front surface of the wafer and an outer peripheral surplus region surrounding the device region are formed, and a back surface corresponding to the device region is processed thinner than a back surface of the outer peripheral surplus region. A ring-shaped reinforcing portion is formed on the back surface of the outer peripheral surplus area, and is an adhesive film sticking device for sticking a pressure-sensitive adhesive film for die bonding on the back surface of a wafer processed into a concave shape,
Wafer holding means for holding the wafer;
An adhesive film holding means for holding the adhesive film;
The wafer holding means and the adhesive film holding means are accommodated, and a space surrounded by the wafer holding means, the adhesive film holding means, and an inner wall of a cylindrical decompression chamber is formed so as to be sealed. A decompression chamber for decompression;
The back surface corresponding to the device area of the wafer held by the wafer holding means in the vacuum chamber and the adhesive film held by the adhesive film holding means are brought close to each other, and the space between the wafer and the adhesive film is reduced. Control means for pressing the adhesive film on the back surface corresponding to the device region of the wafer,
An adhesive film sticking apparatus comprising:   The diameter of the holding surface of the adhesive film holding means is smaller than the inner diameter of the ring-shaped reinforcing portion formed on the back surface of the wafer, and the holding surface of the adhesive film holding means corresponds to the device region. The pressure-sensitive adhesive film sticking apparatus according to claim 1.

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