Method of electroplating semicoductor wafer using variable currents and mass transfer to obtain uniform plated layer
US6110346A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 9, 1999 |
| Grant date | Aug 29, 2000 |
| Priority date | — |
| Expiry date | Sep 9, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S205/915
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
In electroplating a metal layer on a semiconductor wafer, the resistive voltage drop between the edge of the wafer, where the electrical terminal is located, and center of the wafer causes the plating rate to be greater at the edge than at the center. As a result of this so-called "terminal effect", the plated layer tends to be concave. This problem is overcome by first setting the current at a relatively low level until the plated layer is sufficiently thick that the resistive drop is negligible, and then increasing the current to improve the plating rate. Alternatively, the portion of the layer produced at the higher current can be made slightly convex to compensate for the concave shape of the portion of the layer produced at the lower current. This is done by reducing the mass transfer of the electroplating solution near the edge of the wafer to the point that the electroplating process is mass transfer limited in that region. As a result, the portion of the layer formed under these conditions is thinner near the edge of the wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.