JP6173024B2 - Laminated wafer processing method and adhesive sheet - Google Patents

Description

  The present invention relates to a laminated wafer processing method in which a plurality of chips are arranged on a wafer, and an adhesive sheet used in the laminated wafer processing method.

  In recent years, attention has been paid to a three-dimensional mounting technique in which chips formed with integrated circuits and the like are stacked in the thickness direction. In chip-on-wafer (CoW), which is one of three-dimensional mounting techniques, a stacked wafer is formed by arranging a plurality of chips on a wafer serving as a support substrate (see, for example, Patent Document 1). .

  By dividing this laminated wafer into the size of each chip, a laminated chip in which a plurality of chips are arranged in a stacked manner can be formed. A laminated wafer is divided | segmented into the size of each chip | tip with the cutting device provided with a cutting blade, for example (for example, refer patent document 2).

JP 2012-209522 A JP 2007-214201 A

  By the way, an interposer wafer provided with bumps (electrodes) or the like corresponding to the chip to be arranged may be used as the above-described chip-on-wafer support substrate. After the laminated wafer formed using the interposer wafer is divided, the laminated chip is supported on the adhesive sheet so that the interposer wafer side is positioned upward, and inspection of bumps and the like is performed.

  In order to simplify the pre-inspection process, an adhesive sheet may be attached to the chip side of the laminated wafer, and the laminated wafer may be divided with the interposer wafer side positioned upward.

  However, since no chip is arranged in the outer peripheral region (outer peripheral surplus region) of the interposer wafer, this method cannot support the outer peripheral region of the interposer wafer with the adhesive sheet.

  For this reason, when the interposer wafer is divided using this method, there is a possibility that a crack is generated at the boundary between the outer peripheral region and the chip arrangement region (chip region). Moreover, there is a possibility that the end material chips that divide the outer peripheral region are scattered and damage the interposer wafer and the chips.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a laminated wafer processing method capable of appropriately dividing a laminated wafer, and an adhesive sheet used in the laminated wafer processing method. Is to provide.

According to the present invention, it is provided with: a disk-shaped wafer; and a chip laminated on each region of the surface of the wafer partitioned by a plurality of intersecting scheduled lines, and a chip in which a plurality of the chips are laminated A laminated wafer having a region and an outer peripheral surplus region surrounding the chip region, wherein a step is formed between the chip region and the outer peripheral surplus region, on the chip side of the laminated wafer Adhesive sheet adhering step for adhering the adhesive sheet , and dividing the wafer with a laser beam or a cutting blade along the planned dividing line from the wafer back side of the laminated wafer after performing the adhesive sheet adhering step And the adhesive sheet is formed on the glue layer corresponding to the outer peripheral surplus area of the laminated wafer, and the glue layer disposed on the glue layer. Protrusion When having a protrusion portion is formed in an annular shape along the outer peripheral edge of the wafer, projecting diameter of the outer periphery of the raised portion is greater than the diameter of the outer periphery of the wafer, projecting the upper surface of the raised portion, said After having carried out the pressure sensitive adhesive sheet sticking step with respect to the wafer, the chip of the laminated wafer is stuck to the glue layer of the pressure sensitive adhesive sheet, and the outer peripheral area is the protrusion. Provided is a method for processing a laminated wafer, wherein the dividing step is performed on the laminated wafer in a supported state.

Further, according to the present invention, there is provided a pressure-sensitive adhesive sheet used in the method for processing a laminated wafer, wherein the substrate layer, a glue layer disposed on the substrate layer, and the outer peripheral surplus of the laminated wafer A protrusion formed on the glue layer corresponding to the region, and the protrusion is formed in an annular shape along the outer peripheral edge of the wafer, and the diameter of the outer periphery of the protrusion is A pressure-sensitive adhesive sheet is provided in which the upper surface of the protrusion is larger in diameter than the outer periphery of the wafer and has an adhesiveness to the wafer.

  According to the present invention, the laminated wafer is divided in a state where the outer peripheral surplus area of the laminated wafer is supported by the protruding portion of the adhesive sheet using the adhesive sheet having the protrusion corresponding to the outer peripheral surplus area of the laminated wafer. The bending of the laminated wafer during the division can be reduced. As a result, the occurrence of cracks can be suppressed at the boundary between the outer peripheral surplus region and the chip region.

  Moreover, since the outer periphery surplus area | region of a laminated wafer is adhere | attached on the projection part of an adhesive sheet, the scattering of the end material chip which divided | segmented the outer periphery surplus area | region can be suppressed, and damage to a laminated wafer can be prevented. Thus, according to the present invention, the laminated wafer can be appropriately divided.

It is a perspective view which shows the structural example of the laminated wafer which concerns on this Embodiment. It is a perspective view which shows the structural example of the adhesive sheet used by this Embodiment. It is a perspective view which shows typically the adhesive sheet sticking step of this Embodiment. It is a partial cross section side view which shows typically the adhesive sheet sticking step of this Embodiment. It is a partial cross section side view which shows typically the division | segmentation step of this Embodiment.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In this embodiment, a method for processing a laminated wafer in which a wafer is cut and divided by a cutting blade will be described, but the method for processing a laminated wafer of the present invention is not limited to this. For example, a laminated wafer processing method in which a wafer is processed and divided by a laser beam may be used.

  The method for processing a laminated wafer according to the present embodiment includes an adhesive sheet attaching step (see FIGS. 3 and 4) and a dividing step (see FIG. 5). The dividing step is performed by a processing device (cutting device) provided with processing means such as a cutting blade.

  In the adhesive sheet adhering step, an adhesive sheet 14 having a protrusion 18 corresponding to the outer peripheral surplus region 8 of the laminated wafer 2 is attached to the chip 12 side (front surface side) of the laminated wafer 2 on which the plurality of chips 12 are arranged. To wear.

  In the dividing step, the cutting blade 26 is cut from the back surface 4b side of the wafer 4 (the back surface side of the laminated wafer 2), and the wafer 4 is divided along the planned dividing line (street) 10 (see FIG. 1). Hereinafter, the processing method of the laminated wafer according to the present embodiment will be described in detail.

  FIG. 1 is a perspective view showing a configuration example of a laminated wafer that is a target of the laminated wafer processing method according to the present embodiment. As shown in FIG. 1, the laminated wafer 2 according to the present embodiment includes a wafer 4 having a disk-shaped outer shape. The wafer 4 is typically an interposer wafer on which bumps (not shown) and the like are formed, and has a central chip region 6 and an outer peripheral surplus region 8 surrounding the chip region 6.

  The chip region 6 on the surface 4a side of the wafer 4 is divided into a plurality of regions by a plurality of intersecting scheduled lines (streets) 10, and a chip 12 having a predetermined thickness including a device such as an IC is provided in each region. Has been placed. Thereby, a step is generated between the chip region 6 and the outer peripheral surplus region 8.

  In the processing method of the present embodiment, first, the pressure-sensitive adhesive sheet sticking step for sticking the pressure-sensitive adhesive sheet 14 to the chip 12 side (surface side) of the laminated wafer 2 described above is performed. FIG. 2 is a perspective view illustrating a configuration example of the pressure-sensitive adhesive sheet used in the present embodiment.

  As shown in FIG. 2, the pressure-sensitive adhesive sheet 14 used in the present embodiment includes a base sheet 16. The base material sheet 16 has an area that can cover the entire front surface side of the laminated wafer 2, and has a film-like base material layer 16 a (see FIGS. 4 and 5) and a base material layer 16 a. It is comprised with the provided adhesive layer 16b (refer FIG.4 and FIG.5).

  The base material layer 16a of the base material sheet 16 is formed of a resin material such as PO (polyolefin), PVC (polyvinyl chloride), or PET (polyethylene terephthalate). The glue layer 16 b is formed of a resin material such as rubber or acrylic, and exhibits adhesiveness to the chip 12 of the laminated wafer 2.

  An annular protrusion 18 corresponding to the outer peripheral surplus region 8 (outer peripheral surplus region 8 of the wafer 4) of the laminated wafer 2 is provided on the adhesive layer 16 b side of the base material sheet 16. The protrusion 18 includes a base material layer 18a (see FIGS. 4 and 5) having a thickness comparable to the chip 12 of the laminated wafer 2, and a paste layer 18b (see FIGS. 4 and 5) provided on the base material layer 18a. Reference). The adhesive layer 18b is provided on the side opposite to the base sheet 16 (upper surface side of the protruding portion 18).

  The base material layer 18a of the protrusion 18 is formed of a flexible resin material such as PO (polyolefin) or PVC (polyvinyl chloride). The adhesive layer 18 b is formed of a resin material such as rubber or acrylic, and exhibits adhesion to the outer peripheral surplus region 8 of the laminated wafer 2.

  The protrusion 18 is formed, for example, by adhering a tape or the like including the base material layer 18a and the adhesive layer 18b to a position corresponding to the outer peripheral surplus region 8 of the laminated wafer 2 on the base material sheet 16 (adhesive layer 16b). Is done. However, the protrusion 18 is not limited to this. The protrusion 18 only needs to be able to support the laminated wafer 2 to such an extent that the outer peripheral surplus region 8 is not bent in the division step described later.

  For example, a photocurable resin (typically, an ultraviolet curable resin) may be applied to the position corresponding to the outer peripheral surplus region 8 of the laminated wafer 2 and used as the protrusion 18. In this case, after performing the adhesive sheet sticking step, the resin is cured by irradiating light (ultraviolet rays) before the dividing step.

  Further, the protrusion 18 may be made of the same material as that of the adhesive layer 16 b of the base sheet 16. In this case, for example, when the base sheet 16 is formed, the glue layer 16b at a position corresponding to the outer peripheral surplus region 8 of the laminated wafer 2 may be thickened. Of course, the glue layer 16b at a position corresponding to the outer peripheral surplus region 8 of the laminated wafer 2 may be thickened after the base sheet 16 is formed.

  An inner diameter d of the protrusion 18 is set smaller than an outer diameter of the wafer 4. On the other hand, the outer diameter D of the protrusion 18 is preferably set larger than the outer diameter of the wafer 4. Thereby, the request | requirement of the positioning accuracy at the time of sticking the adhesive sheet 14 on the laminated wafer 2 is eased, and an adhesive sheet sticking step can be easily implemented now.

  The pressure-sensitive adhesive sheet 14 configured in this manner is attached to the chip 12 side (surface side) of the laminated wafer 2. FIG. 3 is a perspective view schematically showing the adhesive sheet attaching step, and FIG. 4 is a partial cross-sectional side view schematically showing the adhesive sheet attaching step.

  In the adhesive sheet attaching step, as shown in FIGS. 3 and 4, first, the adhesive sheet 14 is attached to the annular frame 20. Specifically, the protrusion 18 of the adhesive sheet 14 is positioned in the opening 20 a formed in the center of the frame 20. Thereafter, the adhesive sheet 14 is cut according to the shape of the annular frame 20.

  Next, the chip 12 side of the laminated wafer 2 is opposed to the protruding portion 18 side of the adhesive sheet 14 attached to the frame 20, and the protruding portion 18 of the adhesive sheet 14 and the outer peripheral surplus region 8 of the laminated wafer 2 are formed. Adjust the position so that they overlap. Then, the pressure-sensitive adhesive sheet 14 and the laminated wafer 2 are brought close to each other, and the pressure-sensitive adhesive sheet 14 is adhered to the laminated wafer 2.

  As a result, the base sheet 16 corresponding to the region surrounded by the protrusions 18 is bonded to the plurality of chips 12 provided in the chip region 6 of the laminated wafer 2, and the outer peripheral surplus region 8 of the laminated wafer 2 is attached to the plurality of chips 12. The protrusion 18 is bonded.

  Since the protrusion 18 is formed to have the same thickness as the chip 12, the height position of the front surface 4 a (or the back surface 4 b) of the wafer 4 (the height position with respect to the base sheet 16) is the chip. The region 6 and the outer peripheral surplus region 8 supported by the protrusion 18 of the pressure-sensitive adhesive sheet 14 have the same degree.

  Therefore, it is possible to suppress the bending of the outer peripheral surplus area 8 of the wafer 4 in the subsequent division step. In addition, although this adhesive sheet sticking step is implemented by an operator's manual work, for example, you may implement without using an operator's hand using a sheet sticking apparatus etc.

  After the adhesive sheet attaching step, a dividing step for dividing the laminated wafer 2 is performed. FIG. 5 is a partial cross-sectional side view schematically showing the dividing step. In the dividing step, first, the laminated wafer 2 supported by the frame 20 via the adhesive sheet 14 is held on the holding table 22.

  Specifically, the frame 20 is fixed by a clamp 24 provided in the holding table 22, and the chip 12 side of the laminated wafer 2 is sucked and held on the holding table 22 via the adhesive sheet 14.

  Next, the position of the cutting blade 26 is aligned with the division line 10 (not shown in FIG. 5, refer to FIG. 1), and the rotating cutting blade 26 is cut into the back surface 4b side of the wafer 4 and processed. By repeatedly performing this process feed and index feed in a direction perpendicular to the process feed direction, the laminated wafer 2 is divided along the scheduled division line 10.

  The cutting depth of the cutting blade 26 is not particularly limited as long as it is a depth that can completely cut the wafer 4. For example, the depth to the base material sheet 16 of the adhesive sheet 14 may be sufficient, and it may be shallower than that.

  Thus, according to the method for processing a laminated wafer of the present embodiment, the outer peripheral surplus region 8 of the laminated wafer 2 using the adhesive sheet 14 provided with the protrusions 18 corresponding to the outer peripheral surplus region 8 of the laminated wafer 2. Since the laminated wafer 2 is divided with the protrusions 18 of the pressure-sensitive adhesive sheet 14 being supported, the bending of the laminated wafer 2 during the division can be reduced. As a result, it is possible to suppress the occurrence of cracks at the boundary between the outer peripheral surplus region 8 and the chip region 6.

  Moreover, since the outer peripheral surplus area 8 of the laminated wafer 2 is bonded to the protrusion 18 of the adhesive sheet 14, it is possible to prevent the end chip from dividing the outer peripheral surplus area 8 from being scattered and prevent the laminated wafer 2 from being damaged. Thus, according to the present invention, the laminated wafer 2 can be appropriately divided.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above-described embodiment, the laminated wafer processing method for processing the laminated wafer 2 using the cutting blade 26 is shown. However, as the laminated wafer processing method for processing the laminated wafer 2 by irradiating the laser beam, good. In this case, a processing apparatus (laser processing apparatus) including a laser processing head capable of irradiating a laser beam is used.

  Moreover, in the said embodiment, although the adhesive sheet 14 is stuck to the laminated wafer 2 after sticking the adhesive sheet 14 to the flame | frame 20 in the adhesive sheet sticking step, the adhesive sheet sticking step Is not limited to this.

  For example, the adhesive sheet 14 may be attached to the laminated wafer 2 and then attached to the frame 20, and then the adhesive sheet 14 may be cut. In this case, since the adhesive sheet 14 is not attached to the frame 20 when the adhesive sheet 14 and the laminated wafer 2 are attached, surface contact between the adhesive sheet 14 and the laminated wafer 2 can be prevented. Thereby, generation | occurrence | production of the bubble in the interface of the laminated wafer 2 and the adhesive sheet 14 can be suppressed.

  In addition, the configurations, methods, and the like according to the above-described embodiments can be changed as appropriate without departing from the scope of the object of the present invention.

2 Laminated wafer 4 Wafer 4a Front surface 4b Back surface 6 Chip area 8 Peripheral surplus area 10 Scheduled line (street)
12 Chip 14 Adhesive Sheet 16 Base Material Sheet 16a Base Material Layer 16b Adhesive Layer 18 Projection 18a Base Material Layer 18b Adhesive Layer 20 Frame 20a Opening 22 Holding Table 24 Clamp 26 Cutting Blade

Claims (2)

A disk-shaped wafer, and chips stacked on each area of the surface of the wafer divided by a plurality of intersecting scheduled lines, a chip area where the plurality of chips are stacked, and the chip area A peripheral wafer surrounding region, and a method of processing a laminated wafer in which a step is formed between the chip region and the peripheral surplus region,
An adhesive sheet attaching step of attaching an adhesive sheet to the chip side of the laminated wafer;
A step of dividing the wafer with a laser beam or a cutting blade along a line to be divided from the wafer back side of the laminated wafer after performing the adhesive sheet attaching step;
The pressure-sensitive adhesive sheet has a base material layer, a glue layer disposed on the base material layer, and a protrusion formed on the glue layer corresponding to the excess outer peripheral area of the laminated wafer. and, the protrusion portion is formed in an annular shape along the outer peripheral edge of the wafer, projecting diameter of the outer periphery of the raised portion is greater than the diameter of the outer periphery of the wafer, the upper surface of said protrusions with respect to the wafer Have adhesiveness,
After performing the adhesive sheet attaching step, the chip of the laminated wafer is attached to the adhesive layer of the adhesive sheet, and the outer peripheral surplus area is supported by the protrusions on the laminated wafer. A method for processing a laminated wafer, wherein a division step is performed. A pressure-sensitive adhesive sheet used in the method for processing a laminated wafer according to claim 1 ,
A base material layer;
A glue layer disposed on the substrate layer;
A protrusion formed on the adhesive layer corresponding to the outer peripheral surplus area of the laminated wafer,
The protrusion is formed in an annular shape along the outer peripheral edge of the wafer, the outer diameter of the protrusion is larger than the outer diameter of the wafer , and the upper surface of the protrusion is adhesive to the wafer. A pressure-sensitive adhesive sheet comprising:

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