JP6016569B2 - Method of peeling surface protection tape - Google Patents

Description

  The present invention relates to a method for peeling a surface protection tape attached to a wafer with bumps.

  In a semiconductor device manufacturing process, a grid-like divided division line called street is formed on the surface of a wafer made of silicon or a compound semiconductor, and devices such as ICs and LSIs are formed in each region partitioned by the division division line. . After these wafers are ground and thinned to a predetermined thickness, individual semiconductor devices are manufactured by being divided along a street by a cutting device or the like.

  For grinding the back surface of the wafer, for example, a grinding apparatus as disclosed in Japanese Patent Application Laid-Open No. 2002-200545 is used. Grinding is performed by holding the front surface side of the wafer via a surface protection tape with a chuck table of a grinding apparatus, sliding the grinding wheel while contacting the back surface of the wafer, and feeding the grinding wheel by grinding.

  In recent years, as a technology for realizing lighter, thinner, and smaller semiconductor devices, flip chips have been formed by forming a plurality of metal protrusions called bumps on the device surface, and directly bonding these bumps against the electrodes formed on the wiring board. A mounting technique called bonding has been put into practical use (see, for example, JP-A-2001-237278).

  In order to grind a wafer having bumps on the surface, in order to protect the device with bumps formed on the surface, a surface protection tape having a sufficiently thick adhesive layer to embed the bumps on the surface of the wafer is applied. Is common.

JP 2002-200545 A JP 2001-237278 A JP 2012-79911 A

  When the surface protective tape is attached to the bumped wafer, the paste of the surface protective tape enters a slight gap between the outer peripheral side of the reduced diameter portion below the bump and the wafer surface. After the surface protective tape is attached to the bumped wafer, the back surface of the wafer is ground, and the surface protective tape is peeled off from the wafer after a predetermined time has passed through a cleaning process and the like.

  However, even if the surface protection tape is peeled off from the wafer, the adhesive that has improved adhesion to the wafer and bumps after a certain period of time has passed since the surface protection tape was applied to the wafer. There is a problem that it remains in a slight gap between the outer peripheral side of the portion and the wafer surface.

  The present invention has been made in view of the above points, and the object of the present invention is to leave adhesive residue on the surface protection tape in a slight gap between the outer peripheral side of the reduced diameter portion below the bump and the wafer surface. It is an object of the present invention to provide a method for peeling a surface protection tape that can reduce fear.

  According to the present invention, there is provided a surface protection tape peeling method for peeling a surface protection tape from a wafer having a plurality of bumps on the surface and having the surface protection tape attached to the surface via the bumps. Air expansion in which a wafer having a bump and a surface protective tape attached to the surface of the bump is placed in a reduced-pressure atmosphere to expand the air remaining on the outer peripheral side of the lower diameter-reduced portion of the bump. There is provided a method for peeling a surface protection tape, comprising: a step; and a peeling step of peeling the surface protection tape from a wafer after performing the air expansion step.

  Preferably, the stripping step is performed in a reduced pressure atmosphere following the air expansion step.

  According to the present invention, by placing the wafer with bumps in a reduced-pressure atmosphere before peeling off the surface protection tape from the wafer, air remaining between the lower diameter-reduced portion of the bumps and the wafer surface and the surface protection tape is removed. Since it expands, the glue adhered to the bumps and the wafer surface is peeled off once.

  If the surface protective tape is peeled from the wafer with bumps in this state, the possibility that the adhesive residue of the surface protective tape is generated in a slight gap between the outer peripheral side of the reduced diameter portion below the bump and the wafer surface can be reduced.

  When the peeling step is performed in a reduced-pressure atmosphere, the air remaining between the lower diameter-reduced portion of the bump and the surface protection tape expands and the surface is protected in a state where the adhesive adhered to the bump or wafer surface is peeled off. Since the tape is peeled off, adhesive residue can be prevented more reliably.

It is a surface side perspective view of a wafer with a bump. It is a disassembled perspective view which shows a mode that a surface protection tape is stuck on the wafer with a bump. It is an expanded sectional view of the state where the surface protection tape was stuck on the wafer surface. It is a principal part perspective view of the grinding device which shows a grinding step. FIG. 3 is a cross-sectional view of a wafer unit in which a wafer after grinding is attached to a dicing tape having an outer peripheral portion attached to an annular frame. It is sectional drawing of the decompression chamber explaining an air expansion | swelling step. It is a partially expanded sectional view explaining an air expansion step. It is sectional drawing of the pressure reduction chamber explaining a peeling step.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, a perspective view of a bumped wafer 11 is shown. The wafer 11 has a front surface 11 a and a back surface 11 b, and a plurality of streets (division planned lines) 13 are formed orthogonally on the front surface 11 a, and the devices 15 are respectively provided in the areas partitioned by the streets 13. Is formed.

  As shown in the enlarged view of FIG. 1, a plurality of protruding bumps 17 are formed on the four sides of each device 15. Since the bumps 17 are formed on the four sides of each device 15, the wafer 11 has a bump forming area 19 where the bumps 17 are formed and an outer peripheral surplus area (outer peripheral bump non-forming area) 21 surrounding the bump forming area 19. have.

  Referring to FIG. 2, an exploded perspective view showing a state in which the surface protection tape 23 is stuck on the surface 11 a of the wafer 11 is shown. As shown in FIG. 3, the surface protection tape 23 is composed of a base sheet 25 formed from a resin such as polyethylene vinyl chloride or polyolefin, and a glue layer 27 disposed on the base sheet 25.

  As shown in FIG. 3, when the surface protective tape 23 is attached to the surface 11 a of the bumped wafer 11, a slight gap 29 is generated between the lower diameter-reduced portion 17 a of the bump 17 and the surface protective tape 23. Air remains in the gap 29.

  After the surface protective tape 23 is adhered to the front surface 11a of the wafer 11, as shown in FIG. 4, the surface protective tape 23 side is sucked and held by the chuck table 10 of the grinding apparatus, and the back surface 11b of the wafer 11 is exposed to expose the grinding unit. 12, the back surface 11b of the wafer 11 is ground.

  The grinding unit 12 includes a spindle 14 that is rotationally driven, a wheel mount 16 that is fixed to the tip of the spindle 14, and a grinding wheel 18 that is detachably fixed to the wheel mount 16 with a plurality of screws 20. The grinding wheel 18 is composed of a wheel base 22 and a plurality of grinding wheels 24 that are annularly fixed to the outer periphery of the lower end of the wheel base 22.

  In the grinding step, while rotating the chuck table 10 in the direction indicated by the arrow a at 300 rpm, for example, the grinding wheel 18 is rotated in the direction indicated by the arrow b at, for example, 6000 rpm, and the grinding unit feed mechanism (not shown) is operated to operate the grinding wheel. Eighteen grinding wheels 24 are brought into contact with the back surface 11 b of the wafer 11.

  Then, the grinding wheel 18 is ground by a predetermined amount at a predetermined grinding feed speed. The wafer 11 is ground to a desired thickness (for example, 100 μm) while measuring the thickness of the wafer 11 with a contact-type or non-contact-type thickness measurement gauge.

  After finishing the back surface grinding of the wafer 11, the wafer 11 having the surface protective tape 23 attached to the surface is attached to the dicing tape T and the outer periphery of the dicing tape T is attached to the annular frame F as shown in FIG. The wafer unit 26 is formed by wearing. In the wafer unit 26, the wafer 11 is supported by the annular frame F via the dicing tape T.

  After the wafer unit 26 is formed in this way, the wafer unit 26 is accommodated in the decompression vessel 30 and the inside of the chamber 32 is decompressed. When the wafer unit 26 is placed in a reduced-pressure atmosphere, the air remaining in the gap 29 between the lower diameter-reduced portion 17a of the bump 17 and the wafer surface 11a expands as shown in FIG. 29 expands, and according to this, the glue 27 fixed to the bumps 17 and the wafer surface 11a is peeled off once.

  As described above, since the bumps 27 and the glue 27 fixed to the wafer surface 11a are peeled off once, when the wafer unit 26 is taken out from the decompression vessel 30 and the surface protection tape 23 is peeled off from the wafer 11, the lower portion of the bumps 17 is removed. It is possible to reduce the possibility that the adhesive residue of the surface protection tape 23 is generated in the slight gap 29 between the outer peripheral side of the reduced diameter portion 17a and the wafer surface 11a.

  Preferably, as shown in FIG. 8, the peeling step of the surface protection tape 23 is performed in the vacuum vessel 30. In this embodiment, gloves 34 and 36 are disposed in the decompressed chamber 32. Both hands are inserted into the gloves 34 and 36, and the surface protection tape 23 is peeled off with the other hand while holding the wafer unit 26 with one hand.

  When the stripping step is performed in the reduced pressure atmosphere in this way, the air remaining in the gap 29 between the lower diameter-reduced portion 17a of the bump 17 and the surface protection tape 23 expands to the bump 17 and the wafer surface 11a. Since the surface protective tape 23 is peeled off from the wafer 11 in a state where the glue that has been fixed is peeled off, the glue residue can be prevented more reliably.

DESCRIPTION OF SYMBOLS 11 Semiconductor wafer 15 Device 17 Bump 18 Grinding wheel 23 Surface protection tape 25 Base material sheet 26 Wafer unit 27 Glue layer 29 Gap 30 Pressure reduction container 32 Chamber 34, 36 Gloves

Claims (2)

A surface protection tape peeling method for peeling a surface protection tape from a wafer having a plurality of bumps on the surface and having the surface protection tape attached to the surface through the bumps,
A wafer having a plurality of bumps on the surface and having a surface protection tape attached to the surface through the bumps is placed in a reduced-pressure atmosphere to expand the air remaining on the outer peripheral side of the reduced diameter portion of the bumps. An air expansion step,
After performing the air expansion step, a peeling step of peeling the surface protection tape from the wafer;
A method for peeling off a surface protection tape, comprising:   The surface peeling tape peeling method according to claim 1, wherein the peeling step is performed in a reduced-pressure atmosphere following the air expansion step.

Images