Distributed inductively-coupled plasma source and circuit for coupling induction coils to RF power supply
US6825618B2 · kind B2 · utility
Inventors
Key dates
| Filing date | May 20, 2003 |
| Grant date | Nov 30, 2004 |
| Priority date | — |
| Expiry date | May 28, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/321
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Apparatus and method for inductively coupling electrical power to a plasma in a semiconductor process chamber. In a first aspect, an array of wedge-shaped induction coils are distributed around a circle. The sides of adjacent coils are parallel, thereby enhancing the radial uniformity of the magnetic field produced by the array. In a second aspect, electrostatic coupling between the induction coils and the plasma is minimized by connecting each induction coil to the power supply so that the turn of wire of the coil which is nearest to the plasma is near electrical ground potential. In one embodiment, the hot end of one coil is connected to the unbalanced output of an RF power supply, and the hot end of the other coil is connected to electrical ground through a capacitor which resonates with the latter coil at the frequency of the RF power supply.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.