JP5946321B2 - How to apply protective tape - Google Patents

Description

  The present invention relates to a protective tape attaching method for attaching a protective tape to a surface of a wafer.

  A semiconductor wafer in which a number of devices such as IC and LSI are formed on the surface, and each device is partitioned by a line to be divided (street), the back surface is ground by a grinding machine and processed to a predetermined thickness. A dividing line is cut by a cutting device (dicing device) to be divided into individual devices, and the divided devices are widely used in electric devices such as mobile phones and personal computers.

  A grinding apparatus for grinding a back surface of a wafer includes a chuck table for holding a wafer, and a grinding means on which a grinding wheel having a grinding wheel for grinding the wafer held on the chuck table is rotatably mounted. The wafer can be ground to a desired thickness with high accuracy.

  When the back surface of the wafer is ground by the grinding apparatus, a protective tape is attached to the surface of the wafer in order to protect the device formed on the surface. When grinding is finished and the protective tape is peeled off from the wafer surface, part of the adhesive layer remains on the device surface, contaminating the device bumps, bonding pads, etc. In the case of MEMS, there is a problem that the micromachine may be destroyed when the protective tape is peeled off in the case of MEMS.

  In view of this, Japanese Patent Laid-Open No. 2001-196404 has proposed a protective tape having an annular adhesive layer only in a region corresponding to the outer peripheral surplus region of the wafer and no adhesive layer in a region corresponding to the device region.

JP 2001-196404 A

  However, in a protective tape having an annular adhesive layer, it is difficult to position the outer peripheral portion of the protective tape corresponding to the outer peripheral portion of the wafer and attach the protective tape to the wafer. There is a problem that it protrudes from the outer periphery or adheres to the device region.

  The present invention has been made in view of these points, and the object of the present invention is to easily position the protective tape having an annular adhesive layer only on the outer peripheral portion corresponding to the outer peripheral portion of the wafer to the wafer. It is providing the protective tape sticking method which can be stuck.

According to the present invention, in the protective tape attaching method, the protective tape having a diameter corresponding to the diameter of the wafer and having the annular adhesive layer disposed only on the outer peripheral portion corresponding to the outer peripheral portion of the wafer is attached to the wafer. A first mark forming step of forming a plurality of first marks on the outer peripheral portion of the wafer; and a second mark forming step of forming a plurality of second marks corresponding to the first marks on the adhesive layer of the protective tape; A protective tape attaching step of attaching the protective tape to the wafer by matching the first mark of the wafer and the second mark of the protective tape, wherein the first mark comprises a protrusion, The 2 mark is composed of a recess into which the protrusion is inserted, and a protective tape attaching method is provided.

  The method for adhering the protective tape of the present invention is such that the protective tape is adhered to the wafer by aligning the second mark formed on the protective tape with the first mark formed on the wafer. Thus, the annular adhesive layer disposed on the outer peripheral portion of the protective tape can be securely attached to the wafer, and the problem that the adhesive layer protrudes from the outer periphery of the wafer or adheres to the device region can be solved.

1 is a front perspective view of a semiconductor wafer according to an embodiment of the present invention. It is a perspective view of the protective tape which concerns on this invention embodiment. It is the III-III sectional view taken on the line of FIG. It is a disassembled perspective view explaining the protective tape sticking method of this invention. It is a partial cross section side view of the state where the protection tape stuck on the surface of the wafer was sucked and held by the chuck table. It is a perspective view which shows a grinding process.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, there is shown a front side perspective view of a semiconductor wafer 11 according to an embodiment of the present invention. A semiconductor wafer (hereinafter sometimes abbreviated as a wafer) 11 is made of, for example, a silicon wafer having a thickness of 700 μm, and a plurality of division lines (streets) 13 are formed in a lattice shape on the surface 11a. A device 15 such as an IC or LSI is formed in each region partitioned by a plurality of streets 13.

  The wafer 11 configured as described above includes a device region 17 in which the device 15 is formed and an outer peripheral surplus region 19 surrounding the device region 17 on a flat portion of the surface thereof. An arc-shaped chamfer 11e is formed on the outer peripheral edge of the wafer.

  Reference numeral 21 denotes a notch as a mark indicating the crystal orientation of the silicon wafer. Furthermore, a plurality of (two in this embodiment) protrusions 23 are formed as first marks in the outer peripheral surplus region 19 of the wafer 11.

  Referring to FIG. 2, a perspective view of the protective tape 10 according to the embodiment of the present invention is shown. The protective tape 10 includes a base sheet 12 having a diameter substantially the same as the diameter of the wafer 11 to be stuck, and an annular adhesive layer 14 disposed on the outer periphery of the base sheet 12.

  Referring to FIG. 3, the base sheet 12 is formed from a resin such as polyethylene vinyl chloride or polyolefin, and the annular adhesive layer 14 is formed from, for example, an acrylic or rubber paste. Furthermore, the protective tape 10 of this embodiment has two holes or recesses 16 as second marks corresponding to the two protrusions 23 of the wafer 11 in the annular adhesive layer 14 portion.

  In the embodiment described above, two protrusions 23 and two holes 16 are formed, but three or more protrusions 23 and holes 16 may be formed in correspondence. Further, protrusions may be formed in the annular adhesive layer 16 portion of the protective tape 10 and holes corresponding to the protrusions may be formed in the wafer 11.

  In the method for attaching the protective tape of the present invention, as shown in FIG. 4, the hole 16 formed in the protective tape 10 is aligned with the protrusion 23 formed on the wafer 11, and the protective tape 10 is attached to the surface 11 a of the wafer 11. Adhere to.

  By sticking the protective tape 10 to the surface 11 a of the wafer 11 so that the protrusions 23 of the wafer 11 are inserted into the holes 16 of the protective tape 10 in this way, the annular adhesive layer 16 is attached to the outer periphery of the wafer 11. The adhesive layer 14 can be reliably adhered, and the problem that the adhesive layer 14 protrudes from the outer periphery of the wafer 11 or adheres to the device region 17 can be solved.

  After adhering the protective tape 10 to the front surface 11a of the wafer 11, a grinding process is performed in which the back surface 11b of the wafer 11 is ground to thin the wafer 11 to a predetermined finished thickness. In the grinding process, as shown in FIGS. 5 and 6, the protective tape 10 side attached to the front surface 11 a of the wafer 11 is sucked and held by the chuck table 22 of the grinding device to expose the back surface 11 b of the wafer 11.

  The grinding unit 24 of the grinding apparatus includes a spindle 26 that is rotationally driven by a motor, a wheel mount 28 that is fixed to the tip of the spindle 26, and a grinding wheel 30 that is detachably attached to the wheel mount 28 with a plurality of screws 32. Including. The grinding wheel 30 is configured by fixing a plurality of grinding stones 36 in which diamond abrasive grains are hardened by vitrified bond or the like to a free end (lower end) of an annular base 34.

  In the grinding step, while rotating the chuck table 22 in the direction of arrow a at, for example, 300 rpm, the grinding wheel 30 is rotated in the same direction as the chuck table 22, that is, in the direction of arrow b at, for example, 6000 rpm. Driven to bring the grinding wheel 36 into contact with the back surface 11 b of the wafer 11.

  Then, the grinding wheel 30 is ground and fed by a predetermined amount at a predetermined grinding feed speed (for example, 3 to 5 μm / second), and the wafer 11 is ground. While measuring the thickness of the wafer 11 with a contact-type thickness measurement gauge (not shown), the wafer 11 is finished to a finished thickness, for example, 100 μm.

  When the grinding process is completed, the protective tape 10 is peeled off from the surface 11a of the wafer 11. However, the protective tape 10 is merely attached to the outer peripheral surplus area 19 of the wafer 11 with the annular adhesive layer 14, so The adhesive layer is not attached, and the device region 17 is prevented from being contaminated by the residue of the adhesive layer. Moreover, since the protective tape 10 is affixed only to the outer periphery surplus area | region 19, peeling of the protective tape 10 becomes easy.

DESCRIPTION OF SYMBOLS 10 Protective tape 11 Semiconductor wafer 12 Base material sheet 14 Annular adhesion layer 15 Device 16 Hole (concave)
17 Device region 19 Peripheral surplus region 23 Protrusion 30 Grinding wheel 36 Grinding wheel

Claims (1)

A protective tape attaching method for attaching a protective tape having a diameter corresponding to the diameter of a wafer and having an annular adhesive layer disposed only on the outer peripheral portion corresponding to the outer peripheral portion of the wafer to the wafer,
A first mark forming step of forming a plurality of first marks on the outer periphery of the wafer;
A second mark forming step of forming a plurality of second marks corresponding to the first mark on the adhesive layer of the protective tape;
A protective tape attaching step of attaching the protective tape to the wafer by matching the first mark of the wafer and the second mark of the protective tape,
The protective tape sticking method, wherein the first mark is constituted by a protrusion, and the second mark is constituted by a recess into which the protrusion is inserted .

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