Apparatus for polishing periphery of device wafer and polishing method

A polishing apparatus for polishing a periphery of a device wafer, the apparatus comprising:

• a chuck table which chucks the device wafer provided with a metallic film deposited on inclined faces formed by chamfering both sides of the device wafer at the periphery thereof, a peripheral face disposed between the inclined faces, and a front face of the device wafer, and which rotates the device wafer about the axis thereof at a predetermined speed;
• a first inclined-face-polishing member and a second inclined-face-polishing member each having an arc-shaped work face and an axis which is inclined with respect to an axis of the device wafer, the work face of the first inclined-face-polishing member being positioned so as to come into line-contact with the inclined face disposed at the front face of the device wafer and the work face of the second inclined-face-polishing member being positioned opposing the first inclined-face-polishing member so as to come into line-contact with the inclined face disposed at a rear face of the device wafer;
• A peripheral-face-polishing member having an arc-shaped work face and an axis which is parallel to the axis of the device wafer, said work face being positioned so as to come into line-contact with the peripheral face of the device wafer;
• A peripheral-edge-polishing member opposing the peripheral-face-polishing member and being formed as a disc rotatable about an axis thereof either perpendicular or parallel to the axis of the device wafer, a work face of the peripheral-edge-polishing member being positioned so as to come into planar contact with the front face of the device wafer at a peripheral edge thereof.
• at least one feed mechanism for moving the first inclined-face-polishing member, the second inclined-face-polishing member, and the peripheral-face-polishing member, each in a direction parallel to the axis thereof, at least one guide mechanism for supporting the first inclined-face-polishing member, the second inclined-face-polishing member, and the peripheral-face-polishing member, each being movable in a direction perpendicular to the axis thereof, and at least one load-applying mechanism for bringing the first inclined-face-polishing member, the second inclined-face-polishing member, and the peripheral-face-polishing member into contact with the device wafer, each at a predetermined pressure;
• and
• a first guide mechanism for supporting the peripheral-edge-polishing member movable in directions toward and away from the device wafer, a load-applying mechanism for bringing the peripheral-edge-polishing member into contact with the front face of the device wafer at a predetermined pressure, a second guide mechanism for moving the peripheral-edge-polishing member in a radial direction of the device wafer so that the width of the metallic film to be removed is controlled, and a driving source.

A method for polishing a periphery of a device wafer, the method comprising the steps of:

• chucking and rotating the device wafer about an axis thereof at a predetermined speed, the device wafer being provided with a metallic film deposited on inclined faces formed by chamfering both sides of the device wafer at the periphery thereof, a peripheral face disposed between the inclined faces, and a front face of the device wafer;
• bringing an arc-shaped work face of a first inclined-face-polishing member into line-contact with the inclined face disposed at the front face of the device wafer and the arc-shaped work face of a second inclined-face-polishing member into line-contact with the inclined face disposed at a rear face of the device wafer, the first and second inclined-face-polishing members being each inclined with respect to the axis of the device wafer;
• bringing the arc-shaped work face of a peripheral-face-polishing member into line-contact with the peripheral face of the device wafer, the peripheral-face-polishing member being parallel to the axis of the device wafer;
• and
• bringing a disc-shaped work face of a peripheral-edge-polishing member into planar contact with the front face of the device wafer at a peripheral edge thereof, the peripheral-edge-polishing member rotating about an axis thereof either perpendicular or parallel to the axis of the device wafer, wherein the inclined faces, the peripheral face, and the peripheral edge of the device wafer are polished simultaneously by the respective polishing members, whereby an unnecessary part of the metallic film is removed from the periphery of the device wafer.