Other

Speedfam Co Ltd

Speedfam-ipec Co Ltd

Chikai Tanaka

Michihiko Yanagisawa

Yasuhiro Horiike

Shinya Iida

Kazuyuki Tsuruoka

Takeshi Sadohara

To resolve a problem that an etching rate profile is changed by a position of a nozzle relative to a semiconductor wafer and accordingly, at a vicinity of an outer edge of the semiconductor wafer, an accurate machining result is difficult to achieve, gas including activated species produced by plasma is blown from a nozzle locally to a surface of the semiconductor wafer W supported on a wafer table concentrically therewith to thereby remove unevenness on the surface of the semiconductor wafer. In this case, the wafer table is provided with a radius larger than a radius of the semiconductor wafer supported thereby by an outstretched portion to thereby prevent an outer edge from being removed excessively by reflected gas.

Wafer table for local dry etching apparatus

A wafer etching method wherein hydrogen gas, ammonia gas or mixed gas containing one of these gases is added to sulfur hexafluoride gas to suppress the occurrence of white turbidity on the surface of the wafer at the time of etching and to enable high quality mirror polishing of the wafer. In one embodiment, a mixed gas obtained by mixing SF gas G of a bomb and H gas G of a bomb in a predetermined ratio is fed to a discharge tube and a microwave M is generated from a microwave oscillator to cause plasma discharge. Further, the entire surface of the silicon wafer W can be flattened by locally etching the surface of the silicon wafer W by an activated species gas G sprayed from the nozzle portion

Wafer etching method

A wafer flattening system is provided to consecutively and automatically remove the natural oxide film from a wafer and flatten and smooth the wafer so as to improve the surface roughness of the wafer and improve the work efficiency. A step of immersing the wafer in an aqueous solution of hydrofluoric acid of a natural oxide film removing device is performed so as to remove the natural oxide film, then followed by a step of locally etching the surface of the wafer at a local etching apparatus by an activated species gas produced from SF gas to flatten the surface. Then, a step of giving a mirror finish to the wafer surface by a CMP apparatus is performed to smooth it. It is also possible to perform the step of removal of the natural oxide film by spraying the entire surface of the wafer by an activated species gas produced from a mixed gas of CF gas and H gas and possible to perform the step of smoothing by spraying the entire surface of the wafer by an activated species gas produced from a mixed gas of CF gas and O gas.

Wafer flattening system

A local etching apparatus and local etching method improving the throughput of the local etching apparatus by preheating a discharge tube before ignition of the plasma discharge. The local etching apparatus is provided with a plasma generator,, an alumina discharge tube,, and a heater,. The heater,is constituted by a heating wire,, a power source,for supplying voltage to the heating wire,, and a voltage regulator,for controlling the voltage supplied from the power source,to the heating wire,. Due to this, it is possible to heat the alumina discharge tube,to the desired temperature by the heater,immediately before the plasma discharge by the plasma generator,. As a result, there is no need to wait with the local etching work until the alumina discharge tube,rises in temperature to the desired temperature due to the heat by the plasma discharge, that is, it is possible to perform the local etching work immediately after the plasma discharge.

Local etching apparatus

A wafer flattening process designed to flatten the entire surface of the wafer to a higher precision by projecting the fall in the etching rate at the outer peripheral portion of the wafer and forming the outer peripheral portion of the wafer thinner in advance before plasma etching the entire surface of the wafer, a wafer flattening system, and a wafer flattened by the same. The wafer flattening system is provided with a CMP apparatus,and a plasma etching apparatus,are provided. The outer peripheral portion Wb of a wafer W held by a carrier,is polished thinner than an inside portion Wc of the wafer W by the CMP apparatus,having a platen,formed with a recessed surface. Specifically, it is polished so that the maximum thickness at the outer peripheral portion Wb of the wafer W becomes not more than the minimum thickness at the inside portion Wc. Suitably thereafter, the plasma etching apparatus,locally etches the surface Wa of the wafer W to obtain a wafer W with a high flatness without any projecting portion at the outer peripheral portion Wb.

Growing community of inventors

Ayase, Japan

Chikai Tanaka