James D Mullins

US Patent:

20220379426, Dec 1, 2022

Filed:

May 31, 2021

Appl. No.:

17/334829

Inventors:

- Portland OR, US
James Mal - Portland OR, US
Adam Marion - Beaverton OR, US
Stan Meek - Portland OR, US
James Mullins - Hillsboro OR, US

International Classification:

B24B 27/06
B24B 55/02
B24B 51/00

Abstract:

A method cuts semiconductor wafers. The method includes: cutting a semiconductor ingot into a workpiece; and sawing the workpiece into slices using a wire grid having a fixed abrasive grain wire, while moving workpiece towards the wire grid. At a first contact of the workpiece with the wire grid, an initial cutting speed is less than 2 mm/min, coolant flow is less than 0.1 l/h and a wire speed is greater than 20 m/s. The workpiece is then guided through the wire grid until a first cutting depth is reached, and then the coolant flow is increased to at least 2000 l/h. The cutting speed is reduced to less than 70% of the initial cutting speed between the first contact of the workpiece with the wire grid up to a cutting depth of half a diameter of the cylinder, and is then increased.