# US 7,611,766 B2 · Wafer protective sheet

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- Number: US 7,611,766 B2
- Document ID: US7611766B2
- Status: Granted
- Kind: B2
- Application number: 10/550,960
- Filed: 2004-04-08
- Published: 2006-10-26
- Granted: 2009-11-03
- Earliest claimed: 2003-04-10
- Assignees: Achilles Corporation
- Inventors: Masahiko Fuyumuro; Yoshitaka Nakayama; Eiichi Kawashima
- Web page: https://patentgrep.com/patent/US7611766B2

## CPC

- H10P 72/1912: {characterised by shock absorbing elements, e.g. retainers or cushions}
- H10P 72/0442: {Apparatus for placing on an insulating substrate, e.g. tape}
- Y10T 428/216: Ornamental, decorative, pattern, or indicia
- Y10T 428/24628: Nonplanar uniform thickness material
- Y10T 428/24669: Aligned or parallel nonplanarities
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A wafer protective sheet 1 is made of a synthetic resin sheet with a thickness of 80 to 130 μm having a large number of projected parts and recessed parts on its front and rear surfaces. The large number of projected parts and the large number of recessed parts are respectively disposed so that each part is positioned at intersections of lattice stripes, and the projected part and the recessed part are disposed alternately each other. The sheet has such a water-like cross section that the recessed parts in the rear surface match the projected parts on the front surface and the projected parts on the rear surface match the recessed parts in the front surface. The wafer protective sheet 1 has a bending resistance of 30 to 80 mm. The wafer protective sheet 1 of the present invention is sufficiently thin. When the wafer protective sheets are interposed between stacked wafers to protect them, the sheets do not adhere to the wafers. Thus, wafers housed in a container can be protected against vibration during transportation.

## Claims

### Claim 1

A wafer protective sheet comprising a synthetic resin sheet with a thickness of 80 to 130 μm having a large number of projected parts and a large number of recessed parts on the respective front surface and rear surface thereof, wherein:
the large number of projected parts and the large number of recessed parts are respectively so disposed that each part is positioned at intersections of lattice stripes, and the projected part and the recessed part are disposed alternately each other;
the sheet has such a wavy cross section that the recessed parts in the rear surface match the projected parts on the front surface;
the sheet has flat parts oriented parallel to and between the projected parts and the recessed parts;
the projected parts on the rear surface match the recessed parts in the front surface; and
the wafer protective sheet has a bending resistance of 30 to 80 mm.

### Claim 2 (depends on 1)

The wafer protective sheet according to claim 1, wherein the wafer protective sheet is formed of a synthetic resin compound having a flexural modulus of 1.0×103 to 1.2×103 MPa.

### Claim 3 (depends on 1)

The wafer protective sheet according to claim 1, wherein the height of the projected parts and recessed parts is 20 to 50 μm.

### Claim 4 (depends on 1)

The wafer protective sheet according to claim 1, wherein the density of the projected parts and recessed parts, that is, the number of projected parts per area and/or the number of recessed parts per sheet area, is 0.5 to 16 per square centimeter.

### Claim 5 (depends on 1)

The wafer protective sheet according to claim 1, wherein the synthetic resin contains an antistatic agent to exhibit an antistatic property.

### Claim 6 (depends on 5)

The wafer protective sheet according to claim 5, wherein the wafer protective sheet has a surface resistivity of 1012Ω or less.

### Claim 7 (depends on 1)

The wafer protective sheet according to claim 1, wherein the flat parts occupy 60% or more of the total area of the front and rear surfaces of the wafer protective sheet.