Industrial Research And Consultancy Centre
An Electrical Supply Scheme for Multi-wire EDM with time-interleaving.
Abstract
  • Wire Electric Discharge Machining (WEDM) is a non-conventional machining technique, where the machining takes place due to heat produced by sparks between the wire and the workpiece. WEDM can be used for slicing semiconductor ingots to get semiconductor wafers. It is more efficient than the presently used multi-wire saw method, because it can reduce material losses from 40% to 15%, plus it can produce wafers with lesser surface roughness and thinner wafers. 
  • Apart from cutting semiconductor ingots, WEDM is also useful for cutting thin metallic plates required for applications like sputtering targets, cutting rare earth magnetic materials, and so on. WEDM usually employs a single wire as the tool electrode. 
  • However, the advantages of WEDM, can be leveraged only if multi-wire EDM (MWEDM) is developed because a single wire EDM cannot compete with the high throughput (6500-15000 wafers per day) of multi-wire sawing. 
  • However, currently developed MWEDM machines are not yet deployed for production as there are several challenges like wire vibrations, unavailability of dedicated pulse generator topologies, complex mechanical arrangement of wires, and so on. 
  • This patent is about an electrical supply scheme which can reduce the problem of wire vibration and electrical supply to wire.

Type of IP

Faculty

Category of Patent

Department

Societal Impact

Has the potential to reduce the price of semiconductor wafers. This is because as the material losses would be reduced, more wafers can be manufactured from the same amount of material. Apart from cutting semiconductor ingots, there could be other applications of MWEDM as well, for example, cutting thin metallic plates required for applications like sputtering targets, cutting rare-earth magnetic materials, and so on.

Salient technical features and Advantages of the Technology
  • WEDM results in lesser kerf losses (15-20%) against 40% in wire sawing techniques 
  • Ultra-thin wafers (≈ 100 µm) can be cut with WEDM 
  • WEDM does not face problems of large cracks which occur when wire saw is used for slicing hard semiconductor materials like Silicon Carbide (SiC). 
  • The proposed electrical supply scheme included within minimises the deflections and vibrations in the MWEDM connected to the power supply.
Technology readiness level

2

Current Status of Technology

The technology is at TRL 2.

Relevant Industries

Semiconductor wafer manufacturing, manufacturing sputtering targets

Applications or Domain

Cutting silicon wafer ingots, rare earth materials, thin metallic plates all become significantly more economical for the manufacturing industry if they deploy multi-wire electrical discharge machining.