JP4798441B2 - Wafer transfer method and wafer transfer unit - Google Patents

Description

  The present invention relates to a wafer transfer method and a wafer transfer unit for transferring a wafer mounted on a frame via a tape.

  In semiconductor manufacturing processes, etc., wafers with semiconductor devices or electronic parts formed on the surface are subjected to electrical tests in the probing process and then divided into individual chips (also called dies or pellets) in the dicing process. The individual chips are then die bonded to the component base in a die bonding process. After die bonding, wire bonding is performed, and after wire bonding, resin molding is performed to obtain a finished product such as a semiconductor device or an electronic component.

  At this time, as shown in FIG. 5, the wafer after the probing process is bonded on the back side to a resin tape (also called a dicing sheet or dicing tape) S having a thickness of about 100 μm and having an adhesive layer formed on one side. And mounted on a rigid ring-shaped frame F. In this state, the wafer W is transferred 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 uses a thin grindstone called a dicing blade formed of fine diamond abrasive grains and having a thickness of about several tens of μm to divide the wafer W into grind grooves and divide the chips into individual chips T is mainly used. . Further, in recent years, laser light having a focused point inside the wafer W is incident on the wafer W, a plurality of modified regions by multiphoton absorption are formed inside the wafer W, the wafer W is expanded, and individual chips T are expanded. A laser dicing apparatus that divides into two is also used in the dicing process.

  The wafer W that has been diced by these apparatuses is bonded to the tape S on the back surface, so that although the individual chips T are cut into individual chips T, the individual chips T do not fall apart. The wafer state is maintained without breaking the arrangement of each other.

  In recent years, in the dicing process, in order to increase the number of chips formed per wafer W, the dicing blade used in the dicing apparatus has become extremely thin, and the width of the groove L formed by dicing has become extremely narrow. . Further, the wafer W that has been diced by the laser dicing apparatus is in a state where the individual chips T are in contact with each other before being divided into individual chips T by expansion. When a wafer in such a state is transported, the individual chips T come into contact with each other due to the bending of the adhesive sheet and rub against each other due to vibrations during transport, resulting in chipping and microcracks at the edge of the chip T, resulting in product quality. Problem occurs.

To solve this problem, a wafer transfer method has been proposed in which the wafer after dicing is expanded by covering the wafer with a double ring to expand the distance between the chips, and the wafer is transferred while maintaining this state. (For example, refer to Patent Document 1).
JP 2004-146727 A

  According to the technique described in Patent Document 1, since the distance between the chips is widened, the chips do not come into contact with each other, and the chipping of the edge portion and the microcracks are not generated. However, two new rings are required to expand the wafer and maintain its state. Further, since the ring has a height, there is a problem in that when a wafer is stored in a cassette and transported, a new cassette having a matching height is required, which increases the cost.

  SUMMARY OF THE INVENTION The present invention has been made for such a problem, and is a low-cost and easy-to-handle wafer transfer method and wafer transfer that eliminates tape bending, prevents contact between chips, and facilitates wafer transfer. The purpose is to provide units.

  In order to achieve the above object, the invention of claim 1 is characterized in that a wafer is mounted on a frame via a resin tape, and the surface of the tape is opposite to the surface to which the wafer is attached. A plate-like holding plate having an outer diameter larger than the outer diameter of the wafer is joined via an attachment tape to carry the wafer.

  According to the first aspect of the present invention, the wafer is mounted on the frame via the resin tape, and the surface on the opposite side to the surface on which the wafer of the tape is attached is outside the outer diameter of the wafer by about 5 to 10 mm. A holding plate having a large diameter and made of a hard plate material such as glass or silicon wafer is joined via a mounting tape. In this state, dicing of the wafer is performed, and the wafer is transferred with the holding plate attached during the transfer.

  The tape to which the wafer is attached is bent due to the weight of the wafer, the elongation of the tape, or the looseness of the tape during mounting. However, in the wafer transfer method according to the present invention, the holding plate is bonded to the surface of the tape opposite to the surface to which the wafer is attached, so that the weight of the wafer does not apply to the tape and the tape is bent. Does not occur.

As a result, the vibration of the tape is reduced, the individual chips do not come into contact with each other and rub against each other, chipping and microcracks do not occur at the chip edges, and wafers can be transported while maintaining high quality. It becomes. Further, a hard plate-like material such as glass or Si wafer used for the holding plate is a material frequently used in normal processing and can be easily obtained at low cost.
The invention of claim 2 is characterized in that, in the invention of claim 1, the holding plate is joined to the tape so that the center of the holding plate and the center of the wafer substantially coincide.
The invention of claim 3 is the invention according to claim 1 or 2, wherein the shape of the frame is a ring shape, and the outer diameter of the holding plate is smaller than the inner diameter of the ring of the frame. .

The invention of claim 4 is the invention according to any one of claims 1 to 3, wherein the attachment only tape is characterized in that it is formed by a resinous material.

According to the invention of claim 4 , the mounting tape is made of the same material as the tape for mounting a wafer made of resin and having an adhesive layer on one side. The tape for mounting the wafer is easy to obtain and can be easily removed by a process such as irradiation with ultraviolet light. Therefore, the wafer can be easily transported at low cost.

The invention of claim 5 is the invention according to any one of claims 1 to 4, a plurality of holes for the said mounting only tape for sucking air between the tape Installing the tape and said mounting Is characterized by being opened.

According to the invention of claim 5, the mounting only tape, the wafer is a bonded tape and attached only tape not in close contact with the suction air of the portion of the gap made in the vicinity of the outer peripheral portion of the holding plate A plurality of holes are made.

  As a result, the air in the gap is sucked, so that it is reliably sucked and held by a table that performs vacuum suction used during dicing.

A sixth aspect of the invention is characterized in that, in the invention of any one of the first to fifth aspects, the holding plate has a flatness of 50 μm or more.

According to the invention of claim 6 , since the holding plate has a high flatness, the wafer can be diced and transported while maintaining high quality without affecting the accuracy of dicing.

The invention of claim 7 is more than the outer diameter of the wafer to which the wafer is bonded, and is bonded to the surface opposite to the surface to which the wafer is bonded of the tape that mounts the wafer on a ring-shaped frame. A holding plate having a large outer diameter, and a mounting tape for joining the holding plate to the opposite side of the surface of the tape to which the wafer is attached, the opposite side of the holding plate to the tape The wafer is transported by a wafer transport unit composed of a mounting tape that is joined so as to be covered .

According to the invention of claim 7, larger outer diameter than the outer diameter of the wafer, and holding plate formed of a hard plate material, the wafer transfer unit constituted by the mounting tape to mount the holding plate, Bonding is performed so that the holding plate of the wafer transfer unit is in close contact with the surface opposite to the surface on which the wafer of the tape is adhered, so that the holding plate covers from the opposite side of the bonding surface of the holding plate to the tape. .

  As a result, the vibration of the tape is reduced, the individual chips do not come into contact with each other and rub against each other, chipping and microcracks do not occur at the chip edges, and wafers can be transported while maintaining high quality. It becomes.

  As described above, according to the wafer conveyance device and the wafer conveyance unit of the present invention, since the tape is not bent and the vibration of the tape during conveyance is reduced, contact between chips is reduced and high quality is maintained. The wafer can be easily transferred at low cost.

  Hereinafter, preferred embodiments of a wafer transfer method and a wafer transfer unit according to the present invention will be described in detail with reference to the accompanying drawings.

  First, the configuration of a dicing apparatus for dicing a wafer, which is performed before the implementation of the wafer conveyance method according to the present invention, will be described. FIG. 1 is an overall perspective view of the dicing apparatus.

  The dicing apparatus 10 is arranged to face each other for dicing, and includes spindles 11 and 11 with a built-in high-frequency motor with a blade 12 and a wheel cover (not shown) attached to the tip, and a wafer attached in the vicinity of the spindle 11. A microscope 13 for observing W, a work table 16 for sucking and holding the wafer W, and a spinner 15 for spin cleaning the diced wafer W are provided.

  In addition, the dicing apparatus 10 is provided with a cassette 17 storing a number of wafers W mounted on the frame F via the tape S, an elevator 14 on which the cassette 17 is placed and moved up and down, and a workpiece transfer. Are provided with a workpiece transfer device (not shown) for unloading the wafer W from the transfer arms 19 and 19 and the cassette 17.

  A plurality of wafers W diced by such a dicing apparatus 10 are accommodated in a cassette 17 or conveyed one by one to another processing apparatus. For the transportation, an articulated robot, an arm provided on a parallel movement axis, or the like is used.

  Next, the wafer transfer method and wafer transfer unit of the present invention will be described. FIG. 2 is a perspective view of the wafer transfer unit, and FIG. 3 is a top view and a side sectional view showing a state in which the wafer transfer unit is bonded.

  As shown in FIG. 2, the holding plate 1 of the wafer transfer unit is a circular plate member having a flatness of 50 μm or more, and is formed of a hard material such as glass or silicon.

  The wafer transport unit mounting tape 2 is a tape having a thickness of about 100 μm and having an adhesive layer formed on one side like the tape S, and is made of a resin material similar to the tape S.

  As shown in FIG. 3 (b), the holding plate 1 covers the surface of the tape S for mounting the wafer W on the frame F on the surface opposite to the surface to which the wafer W is attached. Be joined.

  As shown in FIG. 3A, the outer diameter of the holding plate 1 is preferably larger by the width l than the outer diameter of the wafer W, and the width l is preferably about 5 mm to 10 mm.

  The wafer W is sucked and diced on the work table 16 shown in FIG. 1 in a state where the holding plate 1 is bonded to the surface of the tape S opposite to the surface on which the wafer W is adhered. The wafer W is equivalent to a state in which the wafer W is placed on a stable hard table by the holding plate 1 having an outer diameter larger than the outer diameter of the wafer W even during conveyance after dicing.

  As a result, the vibration of the tape S is reduced, the individual chips T do not come into contact with each other and rub against each other, and no chipping or microcracks occur at the edges of the chips T, and the wafer W is conveyed while maintaining high quality. It becomes possible to do.

  Further, in the peripheral portion of the mounting tape 2, a portion of the gap 4 between the tape S and the mounting tape 2, which is generated when the holding plate 1 is joined by the mounting tape 2, as shown in FIG. A plurality of holes 3 are provided for venting the air.

  When the wafer W is placed on the work table 16, the mounting tape 2 is attracted to the work table 16 as shown in FIG. Accordingly, the tape S is also attracted to the work table 16. The air in the gap 4 is sucked from the plurality of holes 3 provided in the mounting tape 2 and the gap 4 is in a vacuum state.

  As a result, the tape S is reliably attracted to the work table 16 without being loosened at the gap 4 and does not affect the accuracy during dicing.

  Further, when the wafer W is diced, transported in the dicing apparatus 10 or between other apparatuses, and finally the holding plate 1 is removed, the portion where the tape S and the mounting tape 2 are bonded together On the other hand, the holding plate 1 is removed together with the mounting tape 2 by reducing the adhesive force of the mounting tape 2 by performing a process such as ultraviolet irradiation.

  As described above, according to the wafer conveyance method of the present invention, the wafer is always placed on a stable, hard, larger outer diameter holding plate. As a result, the vibration of the tape is reduced, the individual chips do not come into contact with each other and rub against each other, chipping and microcracks do not occur at the chip edges, and wafers can be transported while maintaining high quality. It becomes.

  Further, a hard plate-like material such as glass or Si wafer used for the holding plate is a material that is frequently used in normal processing and can be easily obtained at a low cost.

  In the present embodiment, the material of the holding plate 1 is a hard material such as glass or silicon. However, the present invention is not limited to this, and has a flatness of 50 μm or more and is equivalent to glass or silicon. If it has higher hardness, it can be suitably used even if resin, metal, or the like is used.

  Further, in the present embodiment, the mounting tape 2 is provided with a plurality of holes 3 in advance, but the holding plate 1 is joined with a tape not provided with the holes 3, and the holes penetrating to the gap portion after joining. May be provided.

  Further, in the present embodiment, the holding plate 1 is bonded before the dicing process. However, the present invention is not limited to this, and the holding plate 1 can be implemented even if the dicing process is completed and bonded before the wafer is transferred. .

The whole perspective view of a dicing apparatus. The perspective view of a wafer conveyance unit. The top view and side surface sectional drawing of a wafer conveyance unit. Side surface sectional drawing which showed the state which mounts a wafer on a worktable. The perspective view which showed the wafer mounted through the tape on the flame | frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Holding plate, 2 ... Mounting tape, 3 ... Hole, 4 ... Gap, 10 ... Dicing device, 11 ... Spindle, 12 ... Blade, 13 ... Microscope, 14 ... Elevator, 15 ... Spinner, 16 ... Worktable, 17 ... Cassette, 19 ... Transfer arm, F ... Frame, S ... Tape, T ... Chip, W ... Wafer

Claims (7)

A wafer is mounted on a frame via a resin tape, and a plate-like holding plate having an outer diameter larger than the outer diameter of the wafer is provided on the surface of the tape opposite to the surface to which the wafer is attached. A wafer transporting method characterized in that the wafer is transported by being bonded so as to cover the mounting tape.   2. The wafer transfer method according to claim 1, wherein the holding plate is bonded to the tape so that a center of the holding plate and a center of the wafer substantially coincide with each other.   3. The wafer transfer method according to claim 1, wherein the frame has a ring shape, and an outer diameter of the holding plate is smaller than an inner diameter of the ring of the frame. The attachment only for tapes, wafer transfer method according to any one of claims 1 to 3, characterized in that it is formed by a resin material. To any one of claims 1 4, characterized in that are opened a plurality of holes for sucking air between the tape and mounting only tape to the mounting only tape The wafer conveyance method as described. The holding plate wafer transport method as claimed in any one of claims 5, characterized in that it flatness 50μm or more. A holding plate having an outer diameter larger than the outer diameter of the wafer, to which the wafer is bonded, and which is bonded to a surface opposite to the surface to which the wafer is bonded, of a tape that mounts the wafer on a ring-shaped frame When,
An attachment tape for joining the holding plate to the opposite side of the surface of the tape to which the wafer is adhered, the attachment tape for joining so as to cover from the opposite side of the joining surface of the holding plate to the tape And a wafer transfer unit.

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