Method for cleaning substrate surface
There is provided a surface cleaning apparatus and method using plasma to remove a native oxide layer, a chemical oxide layer, and a damaged portion from a silicon substrate surface, and contaminants from a metal surface. A mixture of H 2 and N 2 gas is used as a first processing gas. By absorbing potential in a grounded grid or baffle between a plasma generator and a substrate, only radicals are passed to the substrate, and HF gas is used as a second processing gas. Thus a native oxide layer, a chemical oxide layer, or a damaged portion formed on the silicon substrate during etching is removed in annealing step with H 2 flow. The environment of a chamber is maintained constant by introducing a conditioning gas after each wafer process. Therefore, process repeatability is improved.
1. A surface cleaning method using plasma for fabrication of an integrated circuit in a surface cleaning apparatus having a chamber that can be maintained in a vacuum state, a substrate mount for mounting a substrate, a first processing gas inlet for introducing a carrier gas for generation and maintenance of plasma, a plasma generator, a filter for passing only radicals to said substrate, and a second processing gas inlet, the method comprising the steps of:
forming a polymer layer of NxHyFz on a natural oxide layer on said substrate during patterning step wherein forming said polymer layer comprises the steps of generating a plasma by introducing a first processing gas of H 2 and N 2 mixture into said first processing gas inlet and introducing a second processing HF gas into said second processing gas inlet into said plasma; and
removing said polymer layer and said natural oxide layer by annealing wherein components of said polymer layer are decomposed and combined with the components of said natural oxide layer and removed,
further comprising a step of filtering said plasma to pass only radicals after said step of generating said plasma by introducing said first processing gas of H 2 and N 2 mixture and said step of introducing said second processing HF gas into said plasma.
2. The method of claim 1 , further comprising a step of removing a damaged portion of the surface of said substrate after said step of removing said polymer layer and said natural oxide layer by annealing with a flow of H 2 .
3. The method of claim 1 , wherein wall temperature of said cleaning apparatus is maintained at between 50° C. and 120° C. during whole process of said cleaning said surface of said substrate.
4. The method of claim 1 , wherein a flow rate of said H 2 gas is above 180 sccm and a flow rate of N 2 gas is above 1,800 sccm when a gas pressure is 5 Torr and microwave power is at 600 W and a flow rate of HF gas is 48 sccm.