Silicon ingot slicing apparatus using microbubbles and wire electric discharge machining

Patent metadata

Field	Value
Publication number	US-11065783-B2
Application number	US-201715584481-A
Country	US
Kind code	B2
Filing date	May 2, 2017
Priority date	Nov 15, 2016
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

Provided are a silicon ingot slicing apparatus capable of slicing silicon ingots in various forms such as blocks or wafers using microbubbles and wire electric discharge machining.

First claim

What is claimed is:

1. A silicon ingot slicing apparatus using microbubbles and wire electric discharge machining, the silicon ingot slicing apparatus comprising:
a water tank containing a jig attached to a lower surface of a silicon ingot, a conductive adhesive layer adhered between the silicon ingot and the jig, and deionized water (DIW);
an electrode connected to the silicon ingot;
a wire for slicing the silicon ingot while being transported in a first direction by a wire driver;
an additive injection passage for injecting an additive for generating the microbubbles into the water tank; and
a power supply for supplying power to the electrode and the wire so that arc discharge and electrolysis are performed between the silicon ingot and the wire,
wherein the silicon ingot slicing apparatus is configured to:
generate the microbubbles on the surfaces of both the electrode and the silicon ingot by the additive, during application of a DC pulse voltage above 25V and less than 100V, by the power supply, to the electrode and the wire, wherein the generated microbubbles cause a dielectric breakdown of the DIW and an increase in electric discharge frequency of the silicon ingot slicing apparatus, and
slice the silicon ingot by moving the wire in the first direction during the application of the DC pulse voltage, the DC pulse voltage generating the arc discharge between the silicon ingot and the wire,

wherein an entirety of the silicon ingot is contained in the DIW; and
wherein the microbubbles have an average particle diameter of 40 to 60 μm and a volume of the microbubbles is between 5% and 30% a volume of the DIW.

2. The silicon ingot slicing apparatus of claim 1 , wherein the additive for generating microbubbles is a compound comprising one or both of H and OH groups.

3. The silicon ingot slicing apparatus of claim 1 , further comprising:
an outlet for discharging the DIW and the microbubbles from the water tank for controlling the amount of the DIW and the microbubbles; and
an electrical conductivity measuring sensor for measuring the electrical conductivity of the DIW.

4. A silicon ingot slicing apparatus using microbubbles and wire electric discharge machining, the silicon ingot slicing apparatus comprising:
a water tank containing a jig attached to a lower surface of a silicon ingot and a conductive adhesive layer adhered between the silicon ingot and the jig;
an electrode connected to the silicon ingot;
a wire for slicing the silicon ingot while being transported in a first direction of the silicon ingot by a wire driver;
a nozzle assembly for injecting deionized water (DIW) and microbubbles onto the surface of the silicon ingot; and
a power supply for supplying power to the electrode and the wire so that an arc discharge is generated between the silicon ingot and the wire,
wherein the silicon ingot slicing apparatus is configured to:
generate the microbubbles to surfaces of both the electrode and the silicon ingot by the nozzle assembly during application of a DC pulse voltage above 25V and less than 100V, by the power supply, to the electrode and the wire, wherein the generated microbubbles cause a dielectric breakdown of the DIW and an increase in electric discharge frequency of the silicon ingot slicing apparatus, and
slice the silicon ingot by moving the wire in the first direction during the application of the DC pulse voltage, the DC: pulse voltage generating the arc discharge between the silicon ingot and the wire,

wherein an entirety of the silicon ingot is contained in the DIW, and
wherein the microbubbles have an average particle diameter of 5 to 80 μm and a volume of the microbubbles is between 5% and 30% a volume of the DIW.

5. The silicon ingot slicing apparatus of claim 4 , further comprising:
an outlet for discharging the DIW and the microbubbles from the water tank for controlling the amount of the DIW and the microbubbles; and
an electrical conductivity measuring sensor for measuring the electrical conductivity of the DIW.

6. The silicon ingot slicing apparatus of claim 4 , wherein the nozzle assembly is a diffusion type nozzle assembly or a slit type nozzle assembly.

7. The silicon ingot slicing apparatus of claim 4 , wherein the microbubbles have an average particle diameter of 40-50 μm.

8. The silicon ingot slicing apparatus of claim 7 , wherein the nozzle assembly includes a plurality of holes, and
wherein an average diameter of the holes of the nozzle assembly is between 50 and 100 μm.

9. The silicon ingot slicing apparatus of claim 1 , wherein the microbubbles have an average particle diameter of 40-50 μm.

Assignees

• Korea Inst Energy Res

Inventors

• Jang Bo-Yun
• Kim Joon-Soo
• Moon Hui-Chan
• Choi Sun-Ho

Classifications

• B28D5/0058

  Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material (B28D5/0005, B28D5/024 take precedence) · CPC title

• B23H9/00

  Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects (heat treatment by cathodic discharge C21D1/38) · CPC title

• B23H7/02

  Wire-cutting · CPC title

• B28D5/045 Primary

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

• B26D7/27

  Means for performing other operations combined with cutting (B26D9/00 takes precedence) · CPC title