Method for simultaneously cutting a multiplicity of wafers from a workpiece

Patent metadata

Field	Value
Publication number	US-2015083104-A1
Application number	US-201414493445-A
Country	US
Kind code	A1
Filing date	Sep 23, 2014
Priority date	Sep 26, 2013
Publication date	Mar 26, 2015
Grant date	—

Abstract

A method for simultaneously cutting a multiplicity of wafers from a cylindrical workpiece having an axis and a notch applied parallel to the axis in a lateral surface of the workpiece includes applying a cut-in beam on the workpiece where the cut-in beam has a head end and a foot end. The head end is inserted into the notch of the workpiece. The workpiece is held with a feed device so as to position an axis of the work piece parallel to the axes of cylindrical wire guide rollers of a wire saw. The cut-in beam is moved through a planar wire web, where the planar wire web has sections of wire arranged parallel to one another and perpendicular to the axes of the wire guide roller. The wire sections are moved the longitudinal wire direction in the presence of abrasives.

First claim

What is claimed is:

1 : A method for simultaneously cutting a multiplicity of wafers from a cylindrical workpiece having an axis and a notch applied parallel to the axis in a lateral surface of the workpiece, the method comprising:
applying a cut-in beam on the workpiece, the cut-in beam having a front end, a rear end, a head end and a foot end, where the head end of the cut-in beam is inserted with a form fit into the notch of the workpiece and the foot end of the cut-in beam protrudes out of the notch; holding the workpiece with a feed device so as to position an axis of the work piece parallel to axes of a cylindrical wire guide rollers of a wire saw; moving the cut-in beam of the workpiece, using the feed device, in a feed direction perpendicularly through a planar wire web, where the planar wire web has sections of wire arranged parallel to one another and perpendicular to the axes of the wire guide roller, the wire sections being guided multiple times in a spiral around grooves in the wire guide rollers such that the cut in beam is moved first with the foot end against the wire web and the work piece is moved first with the notch against the wire web; and moving the wire sections in the longitudinal wire direction by rotation of the wire guide rollers in the same direction and at the same circumferential speed in the presence of abrasives acting as a grinding agent.

2 : The method as recited in claim 1 , wherein the wire sections exhibit constant bending in the feed direction when the workpiece is moved through the wire web.

3 : The method as recited in claim 1 , wherein the wire sections exhibit variable bending in the feed direction when the cut-in beam foot end is moved through the wire web.

4 : The method as recited in claim 3 , wherein the foot end is moved through the wire web such that the bending of the wire sections assumes a maximum which is no longer achieved in the further course of the cutting process.

5 : The method as recited in claim 1 , wherein an adhesive is used to bond the head end of the cut-in beam into the notch when applying the cut-in beam on the workpiece.

6 : The method as recited in claim 1 , wherein the cut-in beam has a height, between the head end and the foot end, which is constant between the front side and the rear side.

7 : The method as recited in claim 1 , wherein the cut-in beam is in the shape of a circular cylinder.

8 : The method as recited in claim 1 , wherein the shape of the cross section of the foot end varies between the front side and the rear side in the feed direction, such that the wire sections cut into the cut-in beam with decreasing engagement lengths.

9 : The method as recited in claim 8 , wherein the shape of the cross section of the foot end becomes increasingly wedge-shaped between the front side and the rear side in the feed direction.

10 : The method as recited in claim 1 , wherein the cut-in beam has a height, between the head end and the foot end, which decreases between the front side and the rear side, such that the wire sections cut commensurately later into the cut-in beam the longer the wire path between the wire sections and a start of the wire web.

11 : The method as recited in claim 1 , further comprising conducting a test cut where the cut-in beam is obviated and the maximum depth of cut-in waves in the wafers is determined,

12 : The method as recited in claim 11 , wherein the height of the foot end is equal to or greater than the maximum depth determined.

13 : The method as recited in claim 1 , wherein the side of the cut in beam side has grooves lying opposite the wire web, the grooves being arranged perpendicularly over the wire sections.

14 : The method as recited in 12 , wherein the grooves are arranged perpendicularly over the wire sections after a position displacement of the wire sections in the direction of the axes of the wire guide rollers, caused by thermal expansion at the operating temperature.

Assignees

• Siltronic Ag

Inventors

• Pietsch Georg

Classifications

• B24B27/0691

  for controlling the feeding or return movement of the saw · CPC title

• B24B27/0633

  using a cutting wire · CPC title

• B23D57/0061 Primary

  of devices for guiding or feeding saw wires · CPC title

• B23D57/0023

  with a plurality of saw wires or saw wires having plural cutting zones · CPC title

• B28D5/045 Primary

  by cutting with wires or closed-loop blades (B28D5/042 takes precedence) · CPC title