JP6063641B2 - Wafer protection member - Google Patents

Description

  The present invention relates to a wafer protection member for protecting the surface of a wafer having a microstructure device on the surface of a MEMS (Micro Electro Mechanical Systems) wafer or the like.

  Semiconductor wafers with various devices formed on the surface are ground and polished in a state where the surface is protected with a protective tape, thinned to a predetermined thickness, and then divided into individual devices with a cutting machine or the like. Is done. In a wafer in which a micromachine device as a device is formed on the surface, there is a problem that if the protective adhesive tape is attached to a device formation portion on the surface, the micromachine device is damaged at the time of peeling. In addition, in a wafer (CMOS wafer) in which a solid-state imaging device as a device is formed, if a protective adhesive tape is attached to a surface device forming portion, the adhesive layer of the protective tape adheres to the solid-state imaging device. There is a problem of causing a defective device. For this reason, an adhesive tape for surface protection and a grinding method have been devised in which an adhesive layer is applied only to the outer peripheral region surrounding the device region, and the wafer is fixed and ground without leaving any residue in the device region ( For example, see Patent Literature 1 and Patent Literature 2).

JP 2005-109433 A Japanese Patent No. 4447280

  However, the adhesive tape for surface protection shown in Patent Document 1 described above, for example, is a wafer in which the device surface is formed flat without bumps, and the adhesive layer is formed in a convex shape in a ring shape. Therefore, a gap is created between the surface device surface and the device protection part when it is attached to the surface, dimples (dents) occur on the ground surface, chipping occurs, and processing quality deteriorates. There is a problem that it cannot be thinned well.

  The present invention has been made in view of the above, and even in the case of a wafer in which the surface of the device is formed flat without forming bumps or the like, the device on the surface side of the wafer can be satisfactorily thinned. An object of the present invention is to provide a wafer protection member that is not damaged or contaminated.

  In order to solve the above-described problems and achieve the object, the wafer protection member according to the present invention is a protection member that protects the surface of the wafer on which the device is formed, and is an outer peripheral region of the wafer on which the device is not formed. An outer peripheral adhesive portion that is attached to the outer peripheral adhesive portion, and a device protection portion that is surrounded by the outer peripheral adhesive portion and contacts the device and protects the device in a non-adhesive state, the outer peripheral adhesive portion and the device protective portion The surface with which the surface of the wafer abuts is formed on the same surface.

  In the wafer protection member of the present invention, since the outer peripheral sticking portion and the device protection portion are formed on the same surface, it is possible to perform good grinding, that is, good thinning. In addition, since the outer peripheral sticking part sticks to the outer peripheral region of the wafer, the adhesive material constituting the outer peripheral sticking part does not adhere to the device on the wafer surface, and therefore the device is damaged or contaminated. Can be avoided.

FIG. 1 is a perspective view showing a wafer whose surface is protected by a wafer protection member according to an embodiment. FIG. 2 is a perspective view showing the wafer protection member and the wafer according to the embodiment. FIG. 3 is a cross-sectional view showing a state in which grinding is performed on the wafer whose surface is protected by the wafer protection member according to the embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

Embodiment
FIG. 1 is a perspective view showing a wafer whose surface is protected by a wafer protection member according to an embodiment. FIG. 2 is a perspective view showing the wafer protection member and the wafer according to the embodiment. FIG. 3 is a cross-sectional view showing a state in which grinding is performed on the wafer whose surface is protected by the wafer protection member according to the embodiment. A wafer protection member 1 according to the present embodiment (hereinafter simply referred to as a protection member) protects a surface WS on which a device D of a wafer W to be thinned by grinding is formed.

  Here, the wafer W to be protected is a semiconductor wafer whose base material is silicon or the like, and as shown in FIG. 1, devices D partitioned in a lattice pattern by a plurality of division lines L are formed on the surface WS. Has been. As shown in FIG. 3, the wafer W has a protective member 1 attached to a surface WS on which a plurality of devices D are formed, and a grinding device 10 partially shown in FIG. The back surface WR is ground and thinned. Note that, on the surface WS of the wafer W, there are provided a device region DR in which the devices D partitioned in a lattice pattern by the division lines L and an outer peripheral region GR in which the devices D are not formed. In this embodiment, as the device D formed on the surface WS of the wafer W, a micromachine device that constitutes a MEMS wafer or a fixed imaging element that constitutes a CMOS wafer is used. Furthermore, bumps or the like are not formed on the surface of the device D, and are formed flat.

  The protection member 1 protects the surface WS of the wafer W on which the device D is formed. As shown in FIGS. 2 and 3, the base member 2, the outer periphery sticking portion 3, and the device protection portion 4. It consists of and.

  The base material 2 is a sheet-like or tape-like one made of a resin such as polyethylene or polyimide having a thickness of about 100 to 200 μm. The planar shape of the base material 2 is formed in a circular shape whose outer diameter is substantially equal to the outer diameter of the wafer W. A thin portion 5 is provided on the outer edge portion of the substrate 2 over the entire circumference.

  The outer periphery sticking part 3 sticks to the outer periphery area | region GR of the wafer W in which the device D is not formed. The outer peripheral sticking portion 3 is made of a synthetic resin having adhesiveness on the surface WS of the wafer W, is provided on the thin portion 5 of the base material 2, and is provided on the outer edge portion of the base material 2 over the entire circumference. ing. The outer periphery sticking part 3 can be comprised with various adhesive agents, such as a pressure sensitive adhesive, a thermosetting adhesive, and a UV curable adhesive.

  The device protection part 4 is surrounded by the outer periphery sticking part 3 and contacts the device D to protect the device D in a non-sticking state. In the present embodiment, the device protection part 4 is formed by a part inside the outer peripheral sticking part 3 of the substrate 2. The surface 6 of the device protection unit 4 comes into contact with the device D in the device region DR provided on the surface WS of the wafer W when the outer periphery bonding unit 3 is bonded to the outer periphery region GR of the wafer W. Moreover, as for the protection member 1, the surface 6 where the surface 7 of the outer periphery sticking part 3 and the surface WS of the wafer W of the device protection part 4 contact | abut is formed in the same surface.

  The protective member 1 having the above-described configuration is cut from the long sheet material constituting the base material 2 in accordance with the outer diameter of the wafer W to obtain the base material 2 having a uniform thickness. And the thickness of the outer edge part of the base material 2 with uniform thickness is cut off over the perimeter, and the thin part 5 is formed. Thereafter, the protective member 1 is obtained by filling the thin-walled portion 5 with a synthetic resin having adhesiveness constituting the outer peripheral sticking portion 3 so as to be flush with the surface 6 of the substrate 2. Then, as shown in FIG. 2, the protective member 1 is overlapped on the surface WS of the wafer W so that the outer peripheral sticking portion 3 faces the surface WS and the outer edge of the protective member 1 coincides with the outer edge of the wafer W. It is done. Then, the protective member 1 is attached to the outer peripheral region GR of the surface WS of the wafer W with the outer peripheral attaching portion 3 and the device protecting portion 4 is brought into contact with the device D in a non-adhesive state. Protect. The protection member 1 is attached to the wafer W while being in close contact with the device D without allowing the device protection unit 4 to enter a foreign substance such as a bubble between the device protection unit 4 and the device D.

  As shown in FIG. 3, the protection member 1 is placed on the chuck table 11 of the grinding apparatus 10 while being attached to the wafer W, and is sucked and held. The protective member 1 is formed on the surface WS of the wafer W during the grinding process in which the grinding wheel 12 of the grinding device 10 is pressed against the back surface WR of the wafer W and is rotated around the central axis to be ground. Protect device D.

  Further, after the grinding process, when the wafer W is picked up from the chuck table 11 of the grinding apparatus 10 and the back surface WR of the wafer W is attached to the dicing tape T (shown in FIG. 1), the protective member 1 is attached to the wafer W. The surface WS is peeled off. An annular frame F is attached to the outer edge of the dicing tape T, and the wafer W is fixed to the annular frame F as shown in FIG. Then, the wafer W is transported to the next process such as a cutting process while being fixed to the annular frame F.

  As described above, since the surface 6 of the device protection unit 4 and the surface 7 of the outer peripheral sticking unit 3 are formed on the same surface, the protection member 1 according to the present embodiment is not formed with bumps or the like. Even if the wafer W has a flat D surface, the outer peripheral sticking portion 3 and the device protection portion 4 are in close contact with each other without generating a gap between the surface W of the wafer W. For this reason, when the wafer W is ground by the grinding device 10 and is thinned, the contact surface pressure between the grinding wheel 12 and the back surface WR of the wafer W can be made uniform, and the grinding is performed satisfactorily. That is, good thinning is possible.

  Moreover, since the outer periphery sticking part 3 sticking to the surface of the wafer W is provided only in the outer edge part of the protection member 1, the outer periphery sticking part 3 does not stick to the device D. For this reason, even if the protection member 1 is peeled from the surface WS of the wafer W, the synthetic resin having adhesiveness constituting the outer peripheral sticking portion 3 does not adhere to the device D on the surface WS of the wafer W. Therefore, the device D can be prevented from being damaged or contaminated. Therefore, according to the protective member 1, even in the case of the wafer W in which the surface of the device D is formed flat without forming bumps or the like, the thinning is possible and the device D on the surface WS of the wafer W is damaged. It is possible to suppress contamination.

  In the embodiment described above, the protection member 1 protects the device D on the surface WS of the wafer W in the grinding process. However, this invention is not limited to this, You may apply to the manufacturing process of various devices D, such as a cutting process and a laser processing process.

  The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Wafer protection member 3 Outer periphery sticking part 4 Device protection part 6 Surface W Wafer WS Surface D Device GR Peripheral area

Claims (1)

A protective member for protecting the surface of the wafer on which the device is formed,
An outer periphery sticking part that is attached to the outer peripheral region of the wafer where the device is not formed,
A device protection part that is surrounded by the outer peripheral adhesive part and that contacts the device and protects the device in a non-adhered state, and the surface of the outer peripheral adhesive part and the surface of the wafer of the device protective part that contact each other are the same Formed with a surface,
The outer periphery sticking part is composed of an adhesive disposed on the surface of the thin part of the base material away from the wafer than the device protection part ,
The thin-walled portion is formed by a surface orthogonal to the surface of the device protection portion and the surface parallel to the surface of the device protection portion .

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