System for improving energy purity and implant consistency, and for minimizing charge accumulation of an implanted substrate
US6237527A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 6, 1999 |
| Grant date | May 29, 2001 |
| Priority date | — |
| Expiry date | Aug 6, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/32412
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A plasma immersion ion implantation method and system is provided for maintaining uniformity in implant energy distribution and for minimizing charge accumulation of an implanted substrate such as a wafer. A voltage modulator (27) applies a pulsed voltage signal (-V.sub.p) to a platen (14) in a process chamber (17) containing a plasma, so that ions in the plasma are attracted by and implanted into a wafer residing on the platen. The voltage modulator (27) comprises: (i) a first switch (50) disposed between a power supply (48) and the platen for momentarily establishing a connection therebetween and supplying the pulsed voltage signal to the platen; (ii) a second switch (54) disposed between the platen (14) and ground for at least momentarily closing to discharge residual voltage (-V.sub.r) from the platen after the first switch (50) opens and the connection between the power supply and the platen is broken; and (iii) a controller (56) for controlling sequential operation of the switches (50, 54). By closing second switch (54) and grounding the platen, (a) only ions within a certain energy level range are implanted into the wafer, improving the implant energy distribution and (b) wa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.