JP2019096811A - Processing method - Google Patents

Abstract

To prevent a residue of glue on a surface of a plate-like object.SOLUTION: A plate-like object placing step is carried out, in which a rear surface Wb of a wafer W is placed on a holding table 11 having a holding surface 11a larger than the wafer W, and a surface Wa is thereby exposed. After the plate-like object placing step is carried out, a sticking step is carried out, in which the surface Wa and the holding surface 11a of the holding table 11 are covered by placing a sheet S with no glue layer formed in an area corresponding to the wafer W, the sheet S is sucked by negative pressure acting on the holding surface 11a, to bring the sheet S into close contact with the surface Wa of the wafer W and, in addition, the sheet S is stuck to the surface Wa of the wafer W by applying heat to the sheet S. Since the sheet S with no glue layer is stuck to the surface Wa of the wafer W, a residue of glue does not occur on the surface Wa of the wafer W after the sheet S is peeled from the wafer W.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a processing method of processing a plate-like object by arranging a surface protection member on the surface of a plate-like object such as a wafer.

  A mounting method called flip chip bonding in which a plurality of metal protrusions called bumps are formed in a device area of a wafer and these bumps are directly bonded to electrodes formed on a wiring substrate has been put to practical use.

  When the back surface of a wafer on which such bumps are formed on the surface is ground, the wafer may be broken during grinding due to the stress caused by the bump step. For this reason, the surface protection member is stuck on the surface of a wafer, and the countermeasure which grinds the back surface of a wafer in the state which embedded the bump in the adhesive layer of the surface protection member is taken.

  However, in the case of using a surface protection member having a thick paste layer in which bumps are embedded, the paste may remain on the device after the surface protection member is peeled off. The operation of removing the glue remaining on the device is complicated and becomes an obstacle in increasing the productivity of the device.

  Then, the surface protection member (surface protection tape) which makes it respond | correspond only to the outer periphery excessive area | region of the wafer in which the bump is not formed is proposed (refer patent document 1). By using this surface protection member, it is possible to prevent the glue from remaining in the device area of the wafer.

JP, 2013-243311, A

  However, even when the surface protection member described in Patent Document 1 is used, the adhesive layer is adhered to the peripheral excess area of the wafer, so the adhesive residual residue is present on the peripheral excess area of the wafer after peeling off the surface protection member. There was a possibility that it would occur, and further improvement was desired.

  The present invention has been made in view of these problems, and its object is to prevent the formation of glue residue on the surface of a plate.

The present invention is a processing method for disposing a surface protection member on the surface of a plate, wherein the back side of the plate is placed on a holding table having a holding surface larger than the plate. After carrying out the plate-like object placing step for exposing the surface and the plate-like object placing step, the sheet having no adhesive layer formed on the region corresponding to the plate-like object is placed on the surface of the plate-like object. The sheet is placed to cover the surface of the plate and the holding surface of the holding table, and the sheet is sucked by a negative pressure acting on the holding surface to adhere the surface of the plate to the sheet, And attaching the sheet to the surface of the plate by heating.
In the processing method described above, the method further includes a frame attaching step of attaching the outer periphery of the sheet to an annular frame with an adhesive member before performing the plate-like object placing step, and the holding table fixes the annular frame. In the plate-like object placement step, the annular frame is preferably fixed by the annular frame fixing portion.
In addition, after carrying out the sticking step, a holding step of holding the plate-like material by the holding means via the sheet to expose the back surface of the plate-like material, and after carrying out the holding step, the plate It is desirable to provide a processing step of processing the back side by processing means.
Furthermore, in the sticking step, it is desirable to heat the sheet via a plate by heating the holding table.

According to the processing method according to the present invention, the plate-like object placing step for placing the back side of the plate-like object on the holding table having the holding surface larger than the plate-like object to expose the surface; After carrying out the loading step, a sheet not formed with a glue layer is placed on the surface of the plate in the region corresponding to the plate, and the surface of the plate and the holding surface of the holding table And suction the sheet by negative pressure acting on the holding surface to bring the sheet into close contact with the surface of the plate, and heating the sheet to stick the sheet to the surface of the plate. Since the sheet having no adhesive layer is attached to the surface of the plate, after the sheet is peeled from the plate, no glue residue is generated on the surface of the plate.
In addition, the method further includes a frame attaching step of attaching the outer periphery of the sheet to the annular frame with an adhesive member before performing the plate placing step, and the holding table includes an annular frame fixing portion fixing the annular frame, When the annular frame is fixed by the annular frame fixing portion in the plate-like material placing step, the possibility of the negative pressure leaking due to the outer peripheral edge of the sheet being twisted in suctioning the sheet in the attaching step can be reduced.

It is a perspective view which shows the wafer which is an example of a plate-like article. It is a perspective view which shows the flame | frame sticking step which sticks the outer periphery of a sheet | seat to an annular frame with an adhesion member. It is a top view which shows an example of a holding table. It is sectional drawing which shows the sticking apparatus containing a holding table. It is sectional drawing which shows the state which covers the surface of the wafer mounted in the holding table of a sticking apparatus, and the holding surface of a holding table with a sheet | seat. It is sectional drawing which shows the affixing step which heats, attracts | sucks a sheet | seat and it sticks on the surface of a plate-like article. It is sectional drawing which shows an example of a holding | maintenance apparatus. It is sectional drawing which shows an example of an adhesion | pasting step. It is a perspective view which shows an example of a process step. It is sectional drawing which shows another example of an adhesion | pasting step.

  The wafer W shown in FIG. 1 is an example of a plate-like object, and on the surface Wa thereof, a plurality of planned dividing lines L are formed in a lattice, and a plurality of areas divided by the planned dividing lines L A device D such as an IC or LSI is formed. A plurality of bumps (convex electrodes) B are formed on the surface of the device D, respectively. The wafer W is formed to have a predetermined thickness by grinding the back surface Wb, for example, and then divided along the planned dividing line L to become chips for each device D.

(1) Frame attachment step In processing the wafer W, as the preparation, as shown in FIG. 2, a circular sheet S, which is a surface protection member for protecting the surface of the wafer W, is attached to the lower surface side of the annular frame F Wear it. The sheet S is made of, for example, a polyolefin, and an adhesive member R is annularly provided on an outer peripheral portion of one surface (upper surface). The adhesive member R is an annular glue layer, and the outer peripheral portion of the sheet S is adhered to the lower surface of the annular frame F by the adhesive member R. The bonding member R is laid only on the portion to be stuck to the annular frame F. In addition, it can replace with cyclic | annular glue as adhesive member R, and a double-sided tape, an adhesive agent, etc. can also be used.

(2) Plate-Like Material Mounting Step After the frame bonding step, the wafer W shown in FIG. 1 is held, for example, on the holding table 11 of the bonding apparatus 10 shown in FIG. 3 and FIG.

  As shown in FIG. 3, two positioning members 22 for positioning the annular frame F shown in FIG. 2 are disposed at two places on the upper surface of the table main body 12. The positioning member 22 is formed of, for example, a pin-like protrusion. Corresponding to this, as shown in FIG. 2, in the outer peripheral part of the annular frame F, two notches K for positioning which engage with the positioning member 22 of the table main body 12 are formed.

  Annular frame fixing portions 23 for fixing an annular frame F are disposed at four positions near the outer periphery of the upper surface of the table main body 12. For example, a magnet capable of attracting and holding an annular frame F made of metal by a magnetic force is used for the annular frame fixing portion 23, and the magnet is embedded inside the table main body 12.

  As shown in FIG. 4, a circular recess 13 is formed in the table body 12, and a disk-shaped porous plate 14 is fitted in the recess 13. The upper surface of the porous plate 14 forms a holding surface 11 a having a diameter larger than that of the wafer W. In the central portion of the table main body 12, a suction passage 15 communicating with the bottom 13a of the recess 13 and the lower surface 12b of the table main body 12 is formed. The suction passage 15 is connected to a suction source 16 via a control valve 17.

  Inside the table body 12, a heating means 18 is provided adjacent to the bottom 13 a of the recess 13. The heating means 18 covers the planar heating element 19 larger in diameter than the holding surface 11 a, the metal plate 20 having good heat conductivity such as aluminum covering the upper surface of the planar heating element 19, and the lower surface of the planar heating element 19. And a heat insulating material 21.

  In this step, as shown in FIG. 5, the control valve 17 is closed, and the back surface Wb side of the wafer W in a state in which the front surface Wa is exposed upward is placed on the holding table 11 of the bonding apparatus 10. .

(3) Bonding step After the plate-like object placing step, the annular frame F with the sheet S attached is placed on the table main body 12. At this time, the annular frame F is accurately positioned on the table body 32 by engaging the two notches K of the annular frame F shown in FIG. 2 with the positioning member 22 shown in FIG. Further, the annular frame F is fixed to the table main body 32 by magnetizing four points of the annular frame F by the magnetic force of the annular frame fixing portion 23 shown in FIG. 2. By fixing the annular frame F to the table main body 32, the surface S a of the wafer W and the holding surface 11a are covered with the sheet S attached to the annular frame F. In this step, as shown in FIG. 6, by opening the control valve 17, negative pressure by the suction source 16 is applied to the holding surface 11a, and the back surface Wb side of the wafer W is sucked. In addition, the sheet S is also sucked by the negative pressure to be in close contact with the surface Wa of the wafer W. The valve opening of the control valve 17 may be performed either before or after the annular frame F to which the sheet S is attached is placed on the table main body 12. Since the sheet S and the annular frame F are adhered to each other by the adhesive member R over the entire circumference, and the annular frame F is fixed by the annular frame fixing portion 23, the outer peripheral edge of the sheet S is twisted when suctioning the sheet S. Thus, the risk of negative pressure leakage can be reduced.

  Next, the planar heating element 19 is energized to generate heat, thereby heating the entire holding table 11. Then, the heat is transmitted to the sheet S through the wafer W, and the sheet S is heated and softened. Then, when the sheet S is softened, the bumps B are buried in the sheet S. Here, the heat generation temperature of the planar heating element 19 is set to, for example, about 100 ° C., and heating is performed from normal temperature for about 1 minute. Thus, when the sheet S is softened, the sheet S is attached to the surface Wa of the wafer W. This sheet S serves as a surface protection member that protects the surface Wa when processing the wafer W later. The wafer W and the sheet S may be placed on the holding table 11 after the heat generation temperature of the planar heating element 19 reaches about 100 ° C., and heating may be performed for about 20 seconds.

  At the time of heating, since the lower surface of the planar heating element 19 is covered with the heat insulating material 21, heat transfer to the lower surface 12 b side of the table main body 12 can be suppressed. On the other hand, since the upper surface of the planar heating element 19 is covered by the metal plate 20 having good heat conductivity, the upper portion of the table main body 12 holding the wafer W can be heated well.

(4) Holding Step After the sticking step, the control valve 17 shown in FIG. 6 is closed to release the suction holding of the wafer W by the holding table 11. Then, the wafer W integrated with the annular frame F via the sheet S is transferred to and held by the holding means 31 of the processing device 30 shown in FIG. The holding means 31 has a metal table body 32. A circular recess 33 is formed in the table body 32, and a disk-shaped porous plate 34 is fitted in the recess 33. The upper surface of the porous plate 34 forms a holding surface 31 a having substantially the same diameter as the wafer W. At the central portion of the table main body 32, a suction passage 35 communicating with the bottom surface 33a of the recess 33 and the lower surface of the table main body 32 is formed. The suction passage 35 is connected to a suction source 36 via a control valve 37. A plurality of clamp portions 38 for fixing the annular frame F are disposed around the table main body 32. The lower part of the holding means 31 is connected to a rotary drive (not shown).

  In this step, as shown in FIG. 8, the wafer W is placed on the holding means 31 via the sheet S with the back surface Wb exposed upward, and the annular frame F is fixed by the four clamp portions 38. Ru. Thereafter, the control valve 37 is opened, and the wafer W is sucked and held on the holding surface 31 a via the sheet S by the negative pressure of the suction source 36.

(5) Processing Step As shown in FIG. 9, the processing apparatus 30 is provided with a grinding means 40 which is a processing means for processing the back surface Wb of the wafer W. The grinding means 40 includes a spindle 41 rotationally driven by a motor (not shown), a wheel mount 42 fixed to the tip of the spindle 41, and a grinding wheel 44 detachably fixed to the wheel mount 42 by a plurality of screws 43. Contains. The grinding wheel 44 is configured of an annular wheel base 45 and a plurality of grinding wheels 46 annularly fixed to the outer periphery of the lower end of the wheel base 45.

  After the holding step, in this step, as shown in FIG. 9, the grinding wheel 44 is in the same direction as the holding means 31 while rotating the holding means 31 holding the wafer W at a predetermined rotational speed in the arrow a direction. The wafer W is rotated in the b direction, and the grinding means 40 is lowered to bring the grinding wheel 46 into contact with the back surface Wb of the wafer W. Then, the wafer W is thinned to a predetermined thickness by moving the grinding means 40 downward at a predetermined grinding feed speed.

  When the processing step is completed, holding of the wafer W in the holding means 31 is released, and the sheet S is peeled off from the surface Wa. The bonding member R of the sheet S is formed only on the portion to be attached to the annular frame F, and not formed on the portion corresponding to the wafer W, so the surface Wa of the wafer W after the sheet S is peeled from the wafer W There is no residue of glue on the

  The embodiments of the present invention are not limited to the above-described embodiments, and various changes, substitutions, and modifications may be made without departing from the scope of the technical idea of the present invention.

  For example, in the above embodiment, the sheet S is heated via the table main body 12, the porous plate 14 and the wafer W by the heating means 18 built in the holding table 11. For example, as shown in FIG. A heating means 50 such as a far infrared heater, a warm air heater, or a lamp may be disposed above the holding surface 11a, and the sheet S may be directly heated from above.

  In the mounting step in the above embodiment, the sheet S is attached to the annular frame F, but the sheet S is directly held on the holding table 11 without attaching the annular frame F to the sheet S. May be In that case, the annular frame fixing portion 23 shown in FIG. 3 for fixing the annular frame F is unnecessary.

  In the above embodiment, the back surface Wb of the wafer W is ground in the processing step. However, in the processing step, the cutting blade is cut along the planned dividing line L from the back surface Wb of the wafer W for cutting Processing, plasma etching the dividing line L by plasma from the back surface Wb side, or irradiating a laser beam from the rear surface Wb to form a modified layer in the inside of the wafer W along the dividing line L Is also possible.

10: sticking device 11: holding table 11a: holding surface 12: table main body 12b: lower surface 13: recess 13a: bottom 14: porous plate 15: suction path 16: suction source 17: control valve 18: heating means 19: planar Heating element 20: Metal plate 21: Thermal insulation 22: Positioning member 23: Annular frame fixing portion 30: Processing device 31: Holding means 31a: Holding surface 32: Table main body 33: Recess 33a: Bottom 34: Porous plate 35: Suction path 36: suction source 37: control valve 38: clamp part 40: grinding means 41: spindle 42: wheel mount 43: screw 44: grinding wheel 45: wheel base 46: grinding wheel 50: heating means S: sheet (surface protection member R: adhesive member F: annular frame K: notch W: wafer Wa: surface B: bump D: device L: division planned la Down Wb: back

Claims (4)

A processing method for disposing a surface protection member on the surface of a plate-like object, comprising
A plate placing step of placing the back side of the plate on a holding table having a holding surface larger than the plate and exposing the surface;
After carrying out the plate-like material placing step, a sheet not formed with a glue layer is placed on the surface of the plate-like material in the region corresponding to the plate-like material to The sheet is covered with the holding surface of the holding table and the negative pressure acting on the holding surface sucks the sheet to bring it into close contact with the surface of the plate and heats the sheet to form the sheet on the surface of the plate And a sticking step of sticking to the surface. The method further comprises a frame attaching step of attaching the outer periphery of the sheet to an annular frame with an adhesive member before performing the plate placing step.
The holding table comprises an annular frame fixing portion for fixing the annular frame;
In the plate-like material placing step, the annular frame is fixed by the annular frame fixing portion.
The processing method according to claim 1. After carrying out the sticking step,
A holding step of holding the plate by the holding means via the sheet to expose the back surface of the plate;
The processing method according to claim 1, further comprising: a processing step of processing the back surface of the plate-like object by processing means after performing the holding step. In the sticking step, the sheet is heated via a plate by heating the holding table.
The processing method according to claim 1.

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