Fixed-abrasive-grain wire, wire saw, and method for slicing workpiece

Patent metadata

Field	Value
Publication number	US-10011046-B2
Application number	US-201515311325-A
Country	US
Kind code	B2
Filing date	Mar 18, 2015
Priority date	May 28, 2014
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

The present invention is a fixed-abrasive-grain wire including a core wire and abrasive grains fixed on a surface of the core wire, wherein an abrasive grain density is 1200 grains/mm 2 or more, where the abrasive grain density is the number of the abrasive grains per unit area on the surface of the core wire, and 2% or less of all distances between centroids of the abrasive grains are equal to or shorter than an average circle equivalent diameter of the whole abrasive grains. There can be provided a fixed-abrasive-grain wire, a wire saw, and a method for slicing a workpiece that can suppress meandering of the fixed-abrasive-grain wire during slicing a workpiece and improve TTV and warp of wafers sliced from the workpiece.

First claim

The invention claimed is:

1. A fixed-abrasive-grain wire comprising a core wire and abrasive grains fixed on a surface of the core wire, wherein
an abrasive grain density is 1200 grains/mm 2 or more, where the abrasive grain density is the number of the abrasive grains per unit area on the surface of the core wire, and 2% or less of all distances between centroids of the abrasive grains are equal to or shorter than an average circle equivalent diameter of the whole abrasive grains.

2. The fixed-abrasive-grain wire according to claim 1 , wherein the abrasive grains are diamond abrasive grains.

3. The fixed-abrasive-grain wire according to claim 1 , wherein the abrasive grains fixed on the surface of the core wire have a particle size distribution in which a minimum grain diameter is 4 μm and a maximum grain diameter is 16 μm.

4. The fixed-abrasive-grain wire according to claim 2 , wherein the abrasive grains fixed on the surface of the core wire have a particle size distribution in which a minimum grain diameter is 4 μm and a maximum grain diameter is 16 μm.

5. A wire saw comprising a wire row formed by spirally winding a fixed-abrasive-grain wire according to claim 1 around a plurality of wire guides, a workpiece-feeding unit for holding a workpiece and pressing the workpiece against the wire row, and a nozzle for supplying a coolant to a contact portion between the workpiece and the wire, wherein the wire saw is configured to slice the workpiece into wafers by pressing the workpiece against the wire row with the workpiece-feeding unit while supplying the coolant to the wire through the nozzle.

6. A wire saw comprising a wire row formed by spirally winding a fixed-abrasive-grain wire according to claim 2 around a plurality of wire guides, a workpiece-feeding unit for holding a workpiece and pressing the workpiece against the wire row, and a nozzle for supplying a coolant to a contact portion between the workpiece and the wire, wherein the wire saw is configured to slice the workpiece into wafers by pressing the workpiece against the wire row with the workpiece-feeding unit while supplying the coolant to the wire through the nozzle.

7. A wire saw comprising a wire row formed by spirally winding a fixed-abrasive-grain wire according to claim 3 around a plurality of wire guides, a workpiece-feeding unit for holding a workpiece and pressing the workpiece against the wire row, and a nozzle for supplying a coolant to a contact portion between the workpiece and the wire, wherein the wire saw is configured to slice the workpiece into wafers by pressing the workpiece against the wire row with the workpiece-feeding unit while supplying the coolant to the wire through the nozzle.

8. A wire saw comprising a wire row formed by spirally winding a fixed-abrasive-grain wire according to claim 4 around a plurality of wire guides, a workpiece-feeding unit for holding a workpiece and pressing the workpiece against the wire row, and a nozzle for supplying a coolant to a contact portion between the workpiece and the wire, wherein the wire saw is configured to slice the workpiece into wafers by pressing the workpiece against the wire row with the workpiece-feeding unit while supplying the coolant to the wire through the nozzle.

9. A method for slicing a workpiece, comprising: preparing a fixed-abrasive-grain wire having a core wire and abrasive grains fixed on a surface of the core wire; forming a wire row by spirally winding the prepared fixed-abrasive-grain wire around a plurality of wire guides; and pressing the workpiece against the wire row while imparting axial reciprocating motion to the fixed-abrasive-grain wire to slice the workpiece into wafers, wherein preparing the fixed-abrasive-grain wire includes the steps of
taking an image of a surface of the fixed-abrasive-grain wire and extracting the abrasive grains on the image by an image binarization analysis,
measuring the number of the extracted abrasive grains and determining an abrasive grain density that is the number of the abrasive grains per unit area,
measuring circle equivalent diameters of the extracted abrasive grains and calculating an average circle equivalent diameter of the whole abrasive grains,
measuring centroids of the extracted abrasive grains and determining all distances between the centroids of the abrasive grains, and
selecting the fixed-abrasive-grain wire if the fixed-abrasive-grain wire satisfies that the determined abrasive grain density is 1200 grains/mm 2 or more, and 2% or less of the determined distances between the centroids of the abrasive grains are equal to or shorter than the calculated average circle equivalent diameter of the whole abrasive grains, whereby the workpiece is sliced with the selected fixed-abrasive-grain wire.

10. The method for slicing a workpiece according to claim 9 , wherein the image of the surface of the fixed-abrasive-grain wire is taken with a scanning electron microscope or a confocal laser microscope.

11. The method for slicing a workpiece according to claim 9 , wherein the abrasive grains are diamond abrasive grains.

12. The method for slicing a workpiece according to claim 10 , wherein the abrasive grains are diamond abrasive grains.

13. The method for slicing a workpiece according to claim 9 , wherein the abrasive grains fixed on the surface of the core wire in the prepared fixed-abrasive-grain wire have a particle size distribution in which a minimum grain diameter is 4 μm and a maximum grain diameter is 16 μm.

14. The method for slicing a workpiece according to claim 10 , wherein the abrasive grains fixed on the surface of the core wire in the prepared fixed-abrasive-grain wire have a particle size distribution in which a minimum grain diameter is 4 μm and a maximum grain diameter is 16 μm.

15. The method for slicing a workpiece according to claim 11 , wherein the abrasive grains fixed on the surface of the core wire in the prepared fixed-abrasive-grain wire have a particle size distribution in which a minimum grain diameter is 4 μm and a maximum grain diameter is 16 μm.

16. The method for slicing a workpiece according to claim 12 , wherein the abrasive grains fixed on the surface of the core wire in the prepared fixed-abrasive-grain wire have a particle size distribution in which a minimum grain diameter is 4 μm and a maximum grain diameter is 16 μm.

Assignees

• Shinetsu Handotai Kk

Inventors

• Kato Tadahiro

Classifications

• H10P90/12

  Preparing bulk and homogeneous wafers · CPC title

• H10P52/00

  Grinding, lapping or polishing of wafers, substrates or parts of devices · CPC title

• B28D5/0076

  for removing dust, e.g. by spraying liquids; for lubricating, cooling or cleaning tool or work · CPC title

• B24D3/004

  with special coatings · CPC title

• B24D11/00

  Constructional features of flexible abrasive materials; Special features in the manufacture of such materials · CPC title