Method of repairing a pedestal surface

Abstract

A method of repairing a pedestal heater uses a diamond film stuck onto a silicon wafer to polish the surface of the heater and so remove distortion, coating or surface scratches.

Description

FIELD OF THE INVENTION [0001] The present invention relates to repairing pedestal surfaces, in particular the top surfaces of pedestal heaters, for instance as are used in chemical vapour deposition (CVD), physical vapour deposition (PVD), semiconductor metal and oxide etching processes or semiconductor processing equipment that require heating or a vacuum to secure the position of a wafer to the pedestal surface. BACKGROUND OF THE INVENTION [0002] Pedestal heaters are for instance used in vapour deposition and etching techniques. The pedestal stands within a reaction chamber, with a wafer sitting atop the pedestal. During the deposition process a reactive gas enters the chamber and is deposited on the wafer, the wafer itself being heated by a heater mechanism within the pedestal. [0003] The wafer is usually clamped to the top of the pedestal by way of differential pressure clamping or electrostatic clamping. Additionally back gases are emitted from the pedestal, around the edges an...

AI Technical Summary

Benefits of technology

[0016] More specifically, the invention is exemplified by a method of repairing a pedestal heater using a diamond film stuck onto a silicon wafer to polish the surface of the heater and so remove distortion, coatings or surface scratches.

Problems solved by technology

If it is too high, this suggests leakage and something must be done about it.

If the completed repair fails to bring the pressure down the pedestal is replaced at great expense.

The problem with this method is that it can take between two to three man-hours to repair a single pedestal.

Further, whilst the pressure differential is improved, the result is still not as good as is desired, for instance the temperature in a wafer, heated by the pedestal may still not be uniform and quite often the pedestal can fail again within a relatively short period.

Even with such repairs, distortion on the heater surface accumulates until such time as this approach can no longer achieve suitable a backside pressure and the heater must be replaced.

In general, the heater lifetime cannot be extended for more then six months after this repair.

Additionally, there can be other types of heater defects, for example: A) Under-Etching during “Plasma clean” (to remove all traces of Tungsten from the entire chamber before it is open for wetclean), due to a defective endpoint detector or RF generator (an endpoint detector detects plasma wavelengths and whether the tungsten film is completely removed from the chamber and commands that the plasma clean is stopped.

If it is faulty then the chamber will not be cleaned.

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