JP2005109044A - Expansion method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive sheet expanding method by which a diced wafer can be transported together with a frame without producing chips nor micro-cracks in the edges of adjacent chips, by preventing the edges of the chips from coming into contact due to vibrations during the transportation of the wafer. <P>SOLUTION: In the adhesive sheet expanding method by which the intervals among individual chips T are expanded by expanding an adhesive sheet S after dicing the wafer, a plate-like thing W and the frame F are relatively separated from each other in the vertical direction, and at the same time, the adhesive sheet S is expanded by imparting a horizontal force to the sheet S. Then the adhesive sheet S is maintained in an expanded state, in which the intervals among the individual chips are expanded by sticking the annular frame F to the expanded adhesive sheet S and cutting the sheet S in the vicinity of the outer periphery of the frame F. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for expanding a pressure-sensitive adhesive sheet, and in particular to a plate-like product mounted on a ring-shaped frame via a pressure-sensitive adhesive sheet and diced into individual chips, the pressure-sensitive adhesive sheet is expanded and individually processed after dicing. The present invention relates to an expanding method for expanding the interval between chips.

  In semiconductor manufacturing processes, etc., wafers that are plate-like products with semiconductor devices or electronic parts formed on their surfaces are subjected to electrical tests in the probing process, and then in the dicing process, individual chips (also referred to as dies or pellets). The individual chips are then die bonded to the component base in a die bonding process. After die bonding, resin molding is performed to complete a finished product such as a semiconductor device or an electronic component.

  After the probing process, as shown in FIG. 5, the back surface of the wafer is attached to an adhesive sheet S (also called a dicing sheet or dicing tape) S having a thickness of about 100 μm with an adhesive layer formed on one side, and a rigid ring. Is mounted on a frame F. In this state, the wafer W is conveyed in the dicing process, between the dicing process and the die bonding process, and in the die bonding process.

  In the dicing process, a dicing apparatus that cuts the wafer by inserting grinding grooves into the wafer W with a thin grindstone called a dicing blade is used. The dicing blade is obtained by electrodepositing fine diamond abrasive grains with Ni, and an extremely thin one having a thickness of about 10 μm to 30 μm is used.

  The dicing blade is rotated at a high speed of 30,000 to 60,000 rpm and cut into the wafer W to completely cut the wafer W (full cut). At this time, since the adhesive sheet S stuck on the back surface of the wafer W is cut only about 10 μm from the front surface, the wafer W is cut into individual chips T, but the individual chips T are separated. In other words, since the arrangement of the chips T is not collapsed, the wafer state is maintained as a whole.

  Further, without using a dicing blade, a laser beam having a focused point is irradiated inside the wafer W to form a modified region due to a multiphoton absorption phenomenon inside the wafer, and the wafer W is started from this modified region. Laser dicing has been proposed to cleave. Also in this laser dicing process, the wafer W is diced as shown in FIG. 5, so that the arrangement of the chips T does not collapse and the wafer state is maintained as a whole.

  Here, even after dicing and dividing into individual chips T in this way, an assembly of the chips T in which the arrangement of the chips T is not broken is also referred to as a wafer W for convenience.

  Thereafter, the wafer W is sent to a die bonding process. A die bonder is used in the die bonding process. In the die bonder, the wafer W is first placed on the expansion stage, and then the adhesive sheet S is expanded, so that the interval between the chips T is widened so that the chips T can be easily picked up.

  Next, the chip T is pushed up with a pusher from below, and the chip T is picked up with a collet from above, and the chip T is bonded to a predetermined position of the base.

As described above, it has been conventionally performed to incorporate an expanding apparatus in the die bonder that widens the adhesive sheet S and widens the distance between the chips T. Various improved inventions of this expanding apparatus have also been made (see, for example, Patent Document 1 and Patent Document 2).
JP 7-23003 A JP 7-321070 A

  In the above-described conventional technology, the wafer W mounted on the frame F through the adhesive sheet S is cut into individual chips T by a dicing blade, and then conveyed in the dicing apparatus as it is to be cleaned. Then, it was transported to the die bonder, and the inside of the die bonder was transported as it was.

  However, in recent years, in a semiconductor device such as an IC, in order to increase the number of chips formed per wafer W, the width of a processing region (also called a street) for dicing processing has become extremely narrow. Therefore, an extremely thin dicing blade having a thickness of about 10 μm to 15 μm has been used in the dicing process.

  In the wafer W diced by such an extremely thin dicing blade and the wafer W diced by the above-mentioned laser dicing, the distance between the chips T is extremely narrow. When transported in a mounted state, the edges of adjacent chips T come into contact with each other due to vibration during transportation, and the edge portion is chipped or microcracked. The problem of compromising the product's reliability occurred.

  For this reason, it has been required to expand immediately after dicing in a dicing apparatus and to convey the chips T with a wider interval. However, even when the conventional expanding method and the expanding method described in Patent Document 1 and Patent Document 2 described above were performed in the dicing apparatus, the expansion was performed when the application of tension to the pressure-sensitive adhesive sheet S was canceled. Since the pressure-sensitive adhesive sheet S contracted again, the wafer W could not be transferred together with the frame F.

  The present invention has been made in view of such circumstances, and even when a wafer having an extremely narrow distance between chips after dicing is used, the edges of adjacent chips are brought into contact with each other due to vibration during conveyance. An object of the present invention is to provide a method for expanding a pressure-sensitive adhesive sheet that can be transported frame by frame without occurrence of chipping, microcracks, or the like in an edge portion.

  In order to achieve the above-mentioned object, the invention according to claim 1 is attached to an adhesive sheet, mounted on a ring-shaped first frame via the adhesive sheet, and diced into individual chips. In the expanding method in which the adhesive sheet is expanded after the dicing process to expand the interval between the individual chips, the plate-like object and the first frame are relatively moved in the vertical direction. A lateral force is applied to the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet is expanded, a ring-shaped second frame is attached to the expanded pressure-sensitive adhesive sheet, and the vicinity of the outer periphery of the second frame The expanded state in which the individual chip intervals are expanded is maintained by cutting the adhesive sheet.

  According to the first aspect of the present invention, the ring-shaped second frame is attached to the expanded adhesive sheet, and the adhesive sheet is cut in the vicinity of the outer periphery of the second frame to maintain the expanded state of the adhesive sheet. The plate-like object can be transported frame by frame while maintaining the distance between the chips. Therefore, even if the distance between chips is extremely narrow, the edges of adjacent chips do not come into contact with each other due to vibration during conveyance, and the edge portion will not be chipped or microcracked. .

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the lateral force applied to the pressure-sensitive adhesive sheet is applied by inflating an air bag.

  According to the invention of claim 2, since the pressure-sensitive adhesive sheet is spread in the lateral direction using the air bag, it can be easily expanded even in a complicated expanded shape.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the first frame and the second frame are the same type of frame.

  According to the invention of claim 3, since the frame in which the plate-like object is mounted via the adhesive sheet and the frame that holds the expanded state of the expanded adhesive sheet are the same type of frame, the frame is shared. In addition to simplifying the apparatus configuration, it is not necessary to change the conveying means in the subsequent steps.

  As described above, according to the expanding method of the present invention, the ring-shaped second frame is attached to the expanded adhesive sheet, and the adhesive sheet is cut in the vicinity of the outer periphery of the second frame to expand the adhesive sheet. Since the state is maintained, the plate-like object can be conveyed for each frame while maintaining the distance between the chips. Therefore, even if the distance between chips is extremely narrow, the edges of adjacent chips do not come into contact with each other due to vibration during conveyance, and the edge portion will not be chipped or microcracked. .

  Hereinafter, preferred embodiments of the expanding method according to the present invention will be described in detail with reference to the accompanying drawings. In each figure, the same number or symbol is attached to the same member.

  FIG. 1 shows an expanding apparatus used in the expanding method according to the embodiment of the present invention. The expanding apparatus 10 includes a base 11, a wafer stage 12 and a frame chuck 13 mounted on the base 11, an air bag 14 provided on the flange 12 </ b> A of the wafer stage 12, and a frame holder disposed above the frame chuck 13. 15. A cutter 16 for cutting the adhesive sheet S is provided.

  The wafer stage 12 is moved up and down by a drive unit (not shown) to move the wafer W, which is a plate-like member, together with the adhesive sheet S up and down. The frame chuck 13 has a cylindrical shape, and a porous member 13A is embedded in the upper surface of the frame chuck 13. The porous member 13A is connected to a vacuum source (not shown), and the frame F, which is the first frame, is attached to the adhesive sheet S. Each is held by suction.

  The air bag 14 provided on the flange 12A of the wafer stage 12 has a tube shape made of a rubber-based elastic member and is connected to a compressed air source (not shown) so as to expand and contract mainly in the lateral direction by the force of the compressed air. It has become.

  A frame holder 15 disposed above the frame chuck 13 is vertically expanded and contracted by a driving means (not shown) and connected to a vacuum source (not shown) so as to suck and hold the new frame F as a second frame. It has become. The new frame F that is the second frame is the same as the frame F that is the first frame.

  In the vicinity of the frame holder 15, it is moved up and down together with the frame holder 15, moved forward and backward toward the outer periphery of the new frame F, and further rotated and moved along the outer periphery of the new frame F. A cutter 16 for separating the sheet S is provided.

  Next, an embodiment of the expanding method according to the present invention will be described based on the flowchart of FIG. In the expanding apparatus 10 used for the expanding method according to the present invention, the wafer W is attached to the adhesive sheet S and mounted on the ring-shaped frame F as the first frame via the adhesive sheet S as shown in FIG. It is thrown in the state.

  The wafer W is placed on the wafer stage 12 via the adhesive sheet S, and the frame F is placed on the frame chuck 13 (step S11). Here, the wafer W has already been diced and divided into individual chips T.

  In this state, the frame F is attracted and fixed to the frame chuck 13 (step S13). FIG. 1 shows this state.

  Next, the wafer stage 12 is extended upward, and the part of the adhesive sheet S to which the wafer W is adhered is lifted upward. At the same time, compressed air is supplied to the airbag 14 to inflate the airbag 14 in the lateral direction.

  As a result, the adhesive sheet S is stretched and the interval between the individual chips T is expanded. FIG. 3 shows this intermediate state. The rising of the wafer stage 12 and the expansion of the air bag 14 are further continued, and the adhesive sheet S is expanded to the state shown in FIG. 4 (step S15).

  At the same time, the new frame F, which is the second frame, is attracted and fixed to the frame holder 15 and lowered (step S17), and the new frame F is attached to the expanded adhesive sheet S (step S19). FIG. 4 shows this state. In this state, the expanded state of the adhesive sheet S in the inner portion of the new frame F is maintained.

  Next, the supply of compressed air that has been supplied to the airbag 14 is stopped, and the communication path is opened to the atmosphere to contract the airbag 14 (step S21).

  Next, the cutter 16 is lowered toward the outer periphery of the new frame F, cut into the adhesive sheet S (step S23), and then the cutter 16 is rotated once along the outer periphery of the new frame F, so that the outer periphery of the new frame F is recovered. The adhesive sheet S on the outer side is cut off (step S25).

  Next, the cutter 16 is moved backward (step S27), and the suction of the new frame F by the frame holder 15 is released.

    Since the expanded state of the adhesive sheet S thus expanded is maintained and the interval between the individual chips T is expanded, the contact between the individual chips T is prevented, and the wafer W can be easily moved together with the new frame F. Can be transported.

  On the other hand, the frame F that has been sucked and held by the frame chuck 13 is released after being sucked. When the adhesive material of the adhesive sheet S attached to the frame F is an ultraviolet curable adhesive, the adhesive sheet S is removed after the adhesive force is weakened by irradiating ultraviolet rays. Moreover, when the adhesive material of the adhesive sheet S is a thermosetting adhesive, the adhesive strength is weakened by heating.

  Since the first frame F and the second frame F are of the same type, the first frame F from which the adhesive sheet S has been removed is used as the next new frame F. Use.

  In this embodiment, the frame F is fixed at a fixed position, the wafer W is moved upward, and the air bag 14 is inflated to expand the adhesive sheet S. However, the present invention is not limited to this, and the wafer W May be fixed at a fixed position, the frame F may be pushed downward, the airbag 14 may be inflated to expand the adhesive sheet S, and the wafer W and the frame F may be relatively spaced apart by a predetermined amount. The airbag 14 may be inflated.

  Moreover, although the airbag 14 was used as a means to stretch the adhesive sheet S in the horizontal direction, the lateral force may be applied to the adhesive sheet S using not only the airbag 14 but also other various mechanical means. .

Side sectional view showing the expanding apparatus used for the expanding method concerning embodiment of this invention The flowchart explaining the expanding method which concerns on embodiment of this invention Side sectional view showing expanding operation 1 Side sectional view 2 showing expansion operation Perspective view showing wafer mounted on frame

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Expand apparatus, 12 ... Wafer stage, 13 ... Frame chuck, 14 ... Air bag, 15 ... Frame holder, 16 ... Cutter, F ... Frame (first frame), New frame (second frame), S ... Adhesive sheet, T ... chip, W ... wafer (plate)

Claims (3)

For the plate-like material that is attached to the pressure-sensitive adhesive sheet and mounted on the ring-shaped first frame through the pressure-sensitive adhesive sheet, and diced into individual chips, the pressure-sensitive adhesive sheet is expanded after dicing, In the expanding method of expanding the interval between individual chips,
The plate-like object and the first frame are relatively spaced apart in the vertical direction, and a lateral force is applied to the pressure-sensitive adhesive sheet to expand the pressure-sensitive adhesive sheet,
Adhering a ring-shaped second frame to the expanded adhesive sheet,
An expanding method in which the expanded state in which the interval between the individual chips is expanded is maintained by cutting the adhesive sheet in the vicinity of the outer periphery of the second frame.   The expanding method according to claim 1, wherein the lateral force applied to the pressure-sensitive adhesive sheet is applied by inflating an airbag.   The expanding method according to claim 1, wherein the first frame and the second frame are the same type of frame.

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