JP4781765B2 - Protective tape for semiconductor wafer back grinding - Google Patents

Description

  The present invention relates to a protective tape for back grinding of a semiconductor wafer that is thinly processed by back grinding.

  A semiconductor wafer typified by a silicon wafer is usually formed into a planar circle having a thickness of 700 to 800 μm. However, if it is left as it is, it is too thick at the time of mounting and becomes an obstacle to miniaturization of electric / electronic devices. In particular, this problem shows a remarkable tendency when semiconductors are stacked and used.

  Therefore, conventionally, after a circuit pattern is formed on the surface of a semiconductor wafer, a back grinding operation is performed in which the back surface of the semiconductor wafer is ground and thinned. Although this back grinding operation is not shown, first, a disposable protective tape is adhered to the surface of the semiconductor wafer on which the circuit pattern is formed, and the semiconductor wafer is sucked and fixed to the chuck table via the protective tape. Is rotated in one direction, and the back surface of the semiconductor wafer is ground while applying a grinding liquid with a grindstone rotating in the opposite direction to the chuck table (see Patent Documents 1 and 2).

In this operation, the protective tape functions to prevent the circuit pattern from being damaged due to friction between the chuck table and the semiconductor wafer, and to prevent the circuit pattern from being contaminated by a grinding liquid including grinding residue.
JP 2005-191296 A JP 2004-31750 A

  The conventional protective tape adheres to the surface on which the circuit pattern of the semiconductor wafer is formed as described above, and is peeled off after the backgrinding operation and disposed of as it is. There is a big problem that the reduction cannot be achieved.

  The present invention has been made in view of the above, and an object of the present invention is to provide a protective tape for backgrinding a semiconductor wafer capable of reducing waste.

In the present invention, in order to solve the above-mentioned problems, a semiconductor wafer back-grinding protective tape for protecting a pattern surface of a semiconductor wafer mounted on a fixed carrier and back-ground with a flexible protective tape ,
The fixed carrier includes a supporting substrate having rigidity, and a deformable holding layer that is attached to the peripheral edge of the surface of the supporting substrate and detachably adheres and holds the semiconductor wafer via a protective tape. A partition space covered with the holding layer is formed on the surface of the substrate, and a plurality of protrusions for supporting the holding layer are formed in the partition space. The holding layer is deformed by exhausting the gas in the partition space to the outside through the supply / discharge hole, and the semiconductor wafer held by the holding layer is removable by this deformation,
The protective tape includes a non-stretchable base material layer made of a synthetic resin film and an adhesion support layer that is laminated and adhered to the base material layer and is detachably adhered to the pattern surface of the semiconductor wafer. The tensile elastic modulus is in the range of 10 to 100 MPa, the adhesion support layer is formed of an elastic elastomer, and the surface of the adhesion support layer that adheres to the pattern surface of the semiconductor wafer is formed on a mirror surface .

  Here, the semiconductor wafer in the claims is not particularly limited to a Si wafer, a GaP wafer, a 200 mm type, a 300 mm type, a 450 mm type, or the like, and an orientation flat or a notch may be formed in the peripheral portion. Not necessarily. A plurality of other layers made of an adhesive sheet or the like may or may not be interposed between the base material layer and the adhesive support layer. Further, the backgrinding protective tape for the semiconductor wafer can be appropriately formed in an arbitrary shape such as a plane circle, a rectangle, or a polygon as long as it contributes to the protection of the semiconductor wafer.

According to the present invention, since the backgrinding protective tape peeled after the backgrinding operation is not discarded as it is, it is used repeatedly, so that resources can be used effectively and waste can be reduced. effective. Further, since the semiconductor wafer is mounted on a fixed carrier that can be easily transported, the semiconductor wafer can be smoothly transferred to the process after back grinding.
In addition, since the backgrinding protective tape can be formed with a thickness that can be easily handled by itself, improvement in workability and handleability can be expected. In addition, since the tensile elastic modulus of the base material layer is in the range of 10 to 100 MPa, it is possible to prevent elongation and contraction during use or difficulty in subsequent operations due to permanent deformation. Furthermore, since the surface of the close contact support layer is a mirror surface, it is possible to prevent air from entering after the close contact support layer is adhered to the semiconductor wafer.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. A protective tape 1 for backgrinding a semiconductor wafer in this embodiment is a non-stretchable base material layer as shown in FIGS. 2 and an elastic adhesion that is detachably adhered to the surface 11 on which the circuit pattern of the semiconductor wafer 10 that is laminated and adhered to the surface that is one side of the base material layer 2 and is back-ground to a thickness of 300 μm or less is formed. A thick multilayer structure including the support layer 3 is formed.

  As shown in FIGS. 3 and 4, the base material layer 2 and the close contact support layer 3 of the backgrinding protective tape 1 have the same size or slightly corresponding to the size of the semiconductor wafer 10 to be backgrinded. Each is formed into a flexible disk shape with an increased diameter.

  The base material layer 2 is formed into a synthetic resin film having a tensile elastic modulus of 10 or more, preferably 10 to 100 MPa, and a thickness of 50 to 200 μm by a manufacturing method using a predetermined synthetic resin. The base material layer 2 is a film whose thickness accuracy is suppressed to about ± 3 μm by a manufacturing method such as casting, extrusion molding, and biaxial stretching after extrusion because high thickness accuracy is required.

  Although it does not specifically limit as a specific material of the base material layer 2, PET, PEN, PI, PAI, PEI, PES, PPS, polyarylate, LCP etc. are used suitably. In addition, the tensile modulus of the base material layer 2 is in the range of 10 to 100 MPa because when the tensile modulus is less than 10 MPa, elongation or shrinkage occurs during use, and conversely, when it exceeds 100 MPa, This is because it causes permanent deformation and makes the next work difficult.

  The adhesion support layer 3 is formed using an elastomer having a JIS A hardness of 20 to 75 and a thickness of 10 to 500 μm. The specific material of the adhesion support layer 3 is not particularly limited, but elastic silicone rubber, fluorine rubber, acrylic rubber, thermoplastic elastomer, and the like are preferably used. Further, the surface of the close-contact support layer 3 is formed in a mirror surface so as to prevent the intrusion of air after adhesion, and Ra has a surface roughness of 3.6 μm or less.

  As shown in FIG. 2, the semiconductor wafer 10 is formed in a plane circle of 300 mm (12 inches) type, and a circuit pattern is formed on the surface 11 which is a mirror surface, and has a thickness of 300 μm or less, preferably 100 μm or less. Be back grounded.

In the above, when the back surface of the semiconductor wafer 10 is back-ground, as shown in FIG. 1, first, the back-grinding protective tape 1 is closely attached to the front surface 11 of the semiconductor wafer 10 on which the circuit pattern is formed. The semiconductor wafer 10 is sucked and fixed to the table 20 via the protective tape 1 for back grinding.
The surface of the chuck table 20 is formed in a substantially hemispherical shape, and the semiconductor wafer 10 is adsorbed and fixed along the curved surface via the back grinding protective tape 1.

  After fixing the semiconductor wafer 10 to the chuck table 20 in this manner, the chuck table 20 is rotated in one direction, and the rotating grindstones 21 are partially brought into contact with the back surface of the semiconductor wafer 10 while supplying pure water 22. The back surface of the semiconductor wafer 10 can be back-ground and processed thinly. In this manner, the semiconductor wafer 10 is back-ground, and then sequentially subjected to a stress relief process and a dicing frame mounting process.

  Then, the backgrinding protective tape 1 is peeled off from the surface 11 of the semiconductor wafer 10 that has undergone the dicing frame mounting process, cleaned as necessary, and then brought into close contact with the surface 11 of the other semiconductor wafer 10 before backgrinding. To do. Thereafter, the above operation is repeated.

  According to the above configuration, the backgrinding protective tape 1 peeled off after the backgrinding operation is not discarded as it is, but it is used repeatedly, so that resources can be used effectively and waste can be greatly reduced. Can do. Furthermore, since the backgrinding protective tape 1 is formed with a thickness that can be easily handled by itself, significant improvement in workability and handling can be expected.

  Next, FIG. 5 and FIG. 6 show a second embodiment of the present invention. In this case, the surface 11 of the semiconductor wafer 10 mounted on the fixed carrier 30 and back-ground is applied to the back-grinding protective tape. 1 to protect.

  The fixed carrier 30 is bonded to the rigid support base 31 and the peripheral edge 32 of the support base 31 and deforms to hold the 300 mm type semiconductor wafer 10 in a detachable manner via the backgrinding protective tape 1. And a flexible holding layer 37 that can be used in a post-semiconductor manufacturing process, and when the semiconductor wafer 10 is transported in the post-semiconductor manufacturing process, the semiconductor wafer 10 is held and highly confidential. It is stored in the substrate storage container.

  The support base 31 and the holding layer 37 of the fixed carrier 30 are each formed into a planar circle having the same diameter or an enlarged diameter as the semiconductor wafer 10. The support base material 31 is formed into a thin plate using a predetermined material, and is formed with a diameter larger than that of the semiconductor wafer 10 so as to be surely stored in the substrate storage container, and the holding layer 37. The flat circular region surrounded by the endless peripheral edge 32 is shallowly flat and recessed.

  The material of the support base 31 is not particularly limited. For example, polycarbonate, polypropylene, polyethylene, and acrylic resin capable of suppressing the amount of deflection when the semiconductor wafer 10 is mounted on the support base 31 to 5 mm or less. , Vinyl chloride resin, aluminum alloy, magnesium alloy, glass, stainless steel and the like.

  A partition space 33 through which air flows is formed between the surface of the recessed region of the support base 31 and the holding layer 37, and round supply / discharge holes 34 communicating with the partition space 33 are formed in the thickness direction. On the recessed surface, a plurality of protrusions 35 that adhere and support the back surface of the holding layer 37 are formed to protrude upward. A vacuum device 36 is detachably connected to the supply / discharge hole 34 of the support base 31 via a tube or the like, and the holding layer 37 is deformed by operating the vacuum device 36 to depressurize the partition space 33.

  The plurality of projections 35 are arranged and formed on the recessed surface of the support base 31 with a gap by a molding method, a sandblast method, an etching method, or the like. Each protrusion 35 is formed in a truncated cone shape or a column shape having substantially the same height as the peripheral surface of the support base 31 and is aligned at a height of 0.05 mm or more, which is less than 0.05 mm. In this case, the partition space 33 having a sufficiently high height cannot be formed, which hinders deformation of the holding layer 37.

  The holding layer 37 is 0.5 to 4 mm larger than the diameter of the semiconductor wafer 10 using a thin elastomer such as urethane, fluorine, silicone, or acrylic that is excellent in flexibility, flexibility, heat resistance, and adhesiveness. It is formed into an expanded thin film, and is bonded to the peripheral surface of the support base 31 via an adhesive or an adhesive layer, and is bonded to the flat tip surface of the plurality of protrusions 35 via an adhesive or an adhesive layer. The

  After the adhesion to the support base 31 and the protrusions 35, the holding layer 37 is deformed into irregularities when the air in the partition space 33 is exhausted to the outside through the supply / exhaust holes 34, and the surface irregularities deformed into the irregularities. The tip surface of the part is ground thinly and flatly by a grinder, a grinding machine or the like, thereby improving the plane accuracy.

  Such a holding layer 37 is continuously deformed in an uneven manner in the XY direction according to the arrangement pattern of the plurality of protrusions 35 by the negative pressure of the partition space 33 by the suction operation of the vacuum device 36, and is closely held. A gap for air inflow is generated between the semiconductor wafer 10 and the backgrinding protective tape 1 so that the held semiconductor wafer 10 can be removed.

The peripheral edge of the semiconductor wafer 10 is curved and formed in a semicircular cross section in the thickness direction, and the semiconductor wafer 10 is in close contact with the holding layer 37 by a transfer pad or a dedicated robot, and the back surface is thinly ground. An orientation flat and a notch for discriminating crystal orientation and aligning are appropriately formed on the peripheral edge of the semiconductor wafer 10.
The base material layer 2 of the backgrinding protective tape 1 that protects the surface 11 of the semiconductor wafer 10 is selectively changed in material as needed or as required. The other parts are the same as those in the above embodiment, and the description thereof is omitted.

  Also in the present embodiment, since the semiconductor wafer 10 is mounted on the fixed carrier 30 that can be expected to have the same effect as the above-described embodiment and can be easily transported, the semiconductor wafer 10 can be smoothly transferred to the process after back grinding. Obviously you can.

It is explanatory drawing which shows the state of the back grinding operation | work in embodiment of the protective tape for back grinding of the semiconductor wafer which concerns on this invention. It is a perspective explanatory view showing a semiconductor wafer in an embodiment of a protection tape for backgrinding of a semiconductor wafer concerning the present invention. It is a perspective explanatory view showing an embodiment of a protection tape for backgrinding of a semiconductor wafer concerning the present invention. It is a section explanatory view showing an embodiment of a protection tape for backgrinding of a semiconductor wafer concerning the present invention. It is a plane explanatory view showing a fixed carrier in a 2nd embodiment of a protection tape for backgrinding of a semiconductor wafer concerning the present invention. It is a fragmentary sectional view showing a fixed carrier in a second embodiment of a protective tape for back grinding of a semiconductor wafer according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Backgrinding protective tape 2 Base material layer 3 Adhesion support layer 10 Semiconductor wafer 11 Surface (pattern surface)
20 Chuck table 21 Grinding stone 22 Pure water 30 Fixed carrier 31 Support base material 32 Peripheral portion 33 Compartment space 34 Supply / exhaust hole 35 Projection 36 Vacuum device 37 Holding layer

Claims (1)

A protective tape for backgrinding of a semiconductor wafer mounted on a fixed carrier and protecting the pattern surface of the semiconductor wafer to be backgrounded with a flexible protective tape ,
The fixed carrier includes a supporting substrate having rigidity, and a deformable holding layer that is attached to the peripheral edge of the surface of the supporting substrate and detachably adheres and holds the semiconductor wafer via a protective tape. A partition space covered with the holding layer is formed on the surface of the substrate, and a plurality of protrusions for supporting the holding layer are formed in the partition space. The holding layer is deformed by exhausting the gas in the partition space to the outside through the supply / discharge hole, and the semiconductor wafer held by the holding layer is removable by this deformation,
The protective tape includes a non-stretchable base material layer made of a synthetic resin film and an adhesion support layer that is laminated and adhered to the base material layer and is detachably adhered to the pattern surface of the semiconductor wafer. The tensile modulus of elasticity is in the range of 10 to 100 MPa, the adhesion support layer is formed of an elastic elastomer, and the surface of the adhesion support layer that adheres to the pattern surface of the semiconductor wafer is formed on a mirror surface . Protective tape for back grinding.

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