Method for cleaning a reactor using electron attachment

Abstract

A method for cleaning, and / or enhancing the cleaning of, a reactor is disclosed herein. In one aspect, there is provided a method comprising: providing the reactor wherein a surface of the reactor is coated with a substance; providing a first and second electrode in close proximity to the reactor wherein the first and second electrode reside within a target area; passing a gas mixture comprising a reactive gas into the target area; supplying energy to at least one of the first or the second electrodes to generate electrons within the target area wherein at least a portion of the electrons attach to at least a portion of the reactive gas thereby forming a negatively charged cleaning gas; contacting the substance with the negatively charged cleaning gas wherein the negatively charged cleaning gas reacts with the substance and forms a volatile product; and removing the volatile product from the reactor.

Description

BACKGROUND OF THE INVENTION [0001] In the manufacture of semiconductor integrated circuits (IC), opto-electronic devices, and microelectro-mechanical systems (MEMS), multiple steps of thin film deposition are performed in order to construct several complete circuits (chips) and devices on monolithic substrate wafers. Each wafer is often deposited with a variety of thin films such as, but not limited to, conductor films, e.g., tungsten; semiconductor films, e.g., doped and undoped poly-crystalline silicon (poly-Si), doped and undoped (intrinsic) amorphous silicon (a-Si), etc.; dielectric films, e.g., silicon dioxide (SiO2), undoped silicon glass (USG), boron doped silicon glass (BSG), phosphorus doped silicon glass (PSG), borophosphrosilicate glass (BPSG), silicon nitride (Si3N4), silicon oxynitride (SiON) etc.; low-k dielectric films, e.g., fluorine doped silicate glass (FSG), and carbon-doped silicon glass, such as “Black Diamond”. [0002] In modern manufacturing, thin film depositi...

AI Technical Summary

Problems solved by technology

Such reactor changes can also lead to deposition process performance drifts and a loss of production yield.

Unfortunately, using perfluorocarbon gases for chamber cleaning has significant adverse environmental impact.

Since perfluorocarbon molecules are very stable, they are difficult to breakdown in plasmas.

Both thermal and plasma activated NF3 chamber cleaning technologies present challenges in NF3 usage, fluorine utilization, and energy consumption.

Unfortunately, certain non-thermal CVD reactors, such as PECVD reactors, use temperature controllers to maintain the reactor at temperatures below 400° C., which is too low for effective thermal NF3 cleaning.

When negative ions dominate over electrons as the charge carrier, the plasma becomes unstable and / or collapses within the reactor thereby leading, inter alia, to incomplete chamber cleaning, poor NF3 utilization, and low NF3 dissociation efficiency.

Further, highly energetic ion bombardment that occurs during in situ cleaning may cause hardware damage.

While remote plasma cleaning alleviates the drawbacks of in situ cleaning, fluorine utilization efficiency is much lower, increasing the overall cost of ownership of the process.

These challenges may impede wider adoption of NF3-based chamber cleaning in the industry.