Patent · US Expired

Method of reducing wafer contamination by removing under-metal layers at the wafer edge

US7169664B2 · kind B2 · utility

1Cited by

9References

17Claims

0Family size

Assignee

Advanced Micro Devices, Inc. · US

Inventors

Axel Preusse · Radebeul, DE
Markus Nopper · Dresden, DE
Holger Schührer · Dresden, DE

Key dates

Filing date	Dec 29, 2003
Grant date	Jan 30, 2007
Priority date	—
Expiry date	Mar 5, 2024

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10S134/902
WIPO fieldSemiconductors
WIPO sectorElectrical engineering

Abstract

According to the present invention, a metal and a barrier material, such as copper and a tantalum-based barrier material, are effectively removed from the wafer edge and especially from the bevel by using an etchant that comprises a diluted mixture of hydrofluoric acid and nitric acid. The method is compatible with currently available etch modules for removing metal from the wafer edge, wherein, depending on the hardware specifics, copper, barrier material and dielectric material may be removed in a single etch step, or a first etch step may be performed substantially without any nitric acid so as to avoid the formation of nitric oxides. In this way, the formation of instable layer stacks may be substantially avoided, thereby reducing the risk of material delamination from the substrate edge.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.