JP3436391B2 - Edge polisher - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge polisher for mirror-polishing the outer peripheral portion of a semiconductor wafer, and more particularly, to a notch in a part of the outer peripheral portion. The present invention relates to an edge polisher for mirror-polishing the outer peripheral portion of a provided disk-shaped wafer. 2. Description of the Related Art An edge polisher for mirror-polishing a chamfered outer peripheral portion of a disk-shaped semiconductor wafer has been conventionally known, for example, as described in JP-A-64-71656. It is. Such an edge polisher is
In general, as shown in FIG. 4, the holding means 2 has a holding means 2 for holding the wafer 1 in a state in which the outer peripheral part is protruded, and a polishing member 3 which comes into contact with the outer circumferential part of the wafer 1 with a constant force. While rotating the wafer 1 around the axis, the rotating polishing member 3 mirror-polishes the wafer outer peripheral portion 1a. On the other hand, a semiconductor wafer 1 has a flat notch (orientation flat) 4 at a part of the outer periphery as shown in FIG. 5, or a recognition mark for X-ray irradiation as shown in FIG. Some have a notch 5 such as a V-shape or a U-shape. Conventionally, these wafers 1 are formed using the same edge polisher regardless of the presence or absence of the notch and the shape of the notch. I was going to polish. However, when a wafer having the notch 5 is polished, the sharp corners 5a of the notch 5 hit the polishing member 3 and easily damage the polishing pad. There was a problem that would. An object of the present invention is to provide an edge polisher in which a polishing member is hardly damaged by a notch of a wafer. [0006] In order to solve the above-mentioned problems, an edge polisher of the present invention holds a disk-shaped wafer having a notch on a part of its outer periphery and rotates it around an axis. Holding means, and a polishing member for polishing the outer periphery of the wafer, wherein the holding means has a chuck surface having a smaller diameter than the wafer capable of holding the wafer with the outer periphery protruding, and the chuck surface And a projection for preventing a corner of the notch from being pressed against the polishing member at a position corresponding to the notch of the wafer. After the notched wafer is held on the chuck surface with the projection in the holding means so that the notch and the projection correspond to each other, the wafer is rotated around the axis. While the polishing member is rotating, the outer peripheral portion of the wafer is mirror-polished. At this time, in the portion where the notch is not formed, the outer periphery of the wafer comes into contact with the polishing member, in the notch formed portion, the projection of the chuck surface contacts the polishing member, and the sharp corner of the notch is polished. Do not touch the member,
Since the contact force is weak even if the contact is made, the polishing pad of the polishing member is hardly damaged by the corner. An embodiment of the present invention will be described below in detail with reference to the drawings. As shown in FIGS. 1 to 3, an edge polisher according to the present invention Holding means 10 for holding and rotating the disc-shaped wafer 1 around an axis, and the chamfered outer peripheral portion 1 of the wafer 1
and a polishing member 11 for mirror-polishing a. The holding means 10 is provided with a plurality of suction holes 13 connected to a vacuum pump (not shown) through through holes 14 on a substantially circular chuck surface 12 having a smaller diameter than the wafer 1. The wafer 1 is held on the wafer 12 such that the outer peripheral portion 1 a excluding the notch portion is protruded from the chuck surface 12 by vacuum suction. The chuck surface 12 has a projection 12a at a position corresponding to the notch 5 of the wafer 1 for preventing the sharp corner 5a of the notch 5 from pressing against the polishing member 11.
Are formed. The protruding portion 12a is used by the polishing
1 prevents the corner 5 a of the notch 5 from pressing against the polishing member 11.
, So that the front end portion occupies at least a position overlapping the circumference of the wafer 1 or a position protruding slightly outside the circumference. On the other hand, the polishing member 11 is formed by wrapping a polishing pad around a cylindrical drum, and has a required angle with respect to the holding means 10 so that the polishing member 11 comes into close contact with the chamfered outer peripheral portion 1a of the wafer. , And can be driven to rotate about an axis. The holding means 10 and the polishing member 11
Although not particularly shown, at least one of them is movable in a direction of coming and going with each other, and is biased in a direction of approaching each other by a constant force by an appropriate load means. Accordingly, even if the wafer 1 is not perfectly circular, the polishing can be performed by relatively shifting the holding means 10 and the polishing member 11 in the contact / separation direction in accordance with the shape thereof. The member 11 is always in contact with a constant force. When the outer peripheral portion 1a of the wafer 1 with the notch 5 is polished by the edge polisher having the above-described structure, FIG.
As shown in FIG. 3, the notch 5 and the projection 1 are placed on the chuck surface 12 with the projection 12a of the holding means 10 as shown in FIG.
After the wafer 1 is held in a positional relationship corresponding to 2a, the outer peripheral portion 1a of the wafer 1 is mirror-polished by the rotating polishing member 11 while the wafer 1 is rotated around the axis by the holding means 10. At this time, the outer peripheral portion 1a of the wafer 1 abuts on the polishing member 11 in a portion where the notch 5 on the outer periphery of the wafer is not formed, and is formed on the chuck surface 12 of the holding means in the notch forming portion. Since the protruding portion 12a comes into contact with the polishing member 11, the sharp corner portion 5a of the notch 5 does not come into contact with the polishing member 11 or comes into contact with the polishing member 11 with a weak force. By 5a, the polishing pad of the polishing member 11 is hardly damaged, and the polishing pad can be used for a long time. When polishing the outer peripheral portion of the wafer 1 on the opposite side, the above operation is repeated by turning the wafer 1 upside down. In the illustrated embodiment, the drum-shaped polishing member 11 is used. However, a disc-shaped polishing member may be used, and the holding means 10 holds the wafer with two disc-shaped chuck members. Needless to say, it may be of a type in which a chuck is held while being held from both sides. As described above, according to the present invention, the notch of the wafer is prevented from pressing against the polishing member by a simple means of providing a projection on a part of the chuck surface of the wafer holding means. Therefore, the polishing pad is hardly damaged, and the polishing pad can be used for a long period of time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a main part of an edge polisher according to the present invention. FIG. 2 is a partial plan view of FIG. FIG. 3 is a plan view showing a state where a wafer of FIG. 2 is removed. FIG. 4 is a front view of a main part of a conventional edge polisher. FIG. 5 is a plan view showing an example of a wafer. FIG. 6 is a plan view showing another example of the wafer. [Description of Signs] 1 Wafer 1a Outer peripheral portion 5 Notch 5a Corner 10 Holding means 11 Polishing member 12 Chuck surface 12a Projection

Claims (1)

(57) Claims: (1) holding means for holding a disk-shaped wafer having a notch in a part of the outer periphery and rotating the wafer around an axis, and a polishing member for polishing the outer periphery of the wafer; The holding means has a chuck surface having a smaller diameter than the wafer capable of holding the wafer in a state in which the outer peripheral portion protrudes, and at a position corresponding to a notch of the wafer on the chuck surface,
An edge polisher comprising a projection for preventing a corner of the notch from pressing against a polishing member.