Polysilicon Film Oxidation Resistance via Nitrogen-Rich Nitride Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing substrate processing methods for semiconductor devices face challenges in inhibiting excessive oxidation of polysilicon films during the recovery of etching damage, as the formation of a nitride layer with high nitrogen concentration is hindered by the presence of an oxygen-containing layer, leading to potential reliability issues due to bird beak formation and decreased capacitance.
Innovation Solution
A substrate processing apparatus and method that modifies an oxygen-containing layer on a polysilicon film into an oxynitride or nitride layer with high nitrogen concentration by heating the substrate and exciting a process gas containing nitrogen and hydrogen, using a combination of a process chamber, heating unit, gas supply unit, excitation unit, and control unit to control the processing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a nitride layer is formed on a substrate with an oxygen-containing layer (native oxide) by supplying nitrogen-containing process gas, then the nitrogen concentration in the nitride layer cannot be increased sufficiently, but this leads to inadequate inhibition of excessive oxidation of polysilicon film sidewalls
Solution Approach 1:
The patent applies preliminary action by forming a preliminary nitride layer on the polysilicon film before the oxidation process. This preliminary nitride layer serves as a protective barrier that prevents excessive oxidation of the polysilicon film sidewalls during subsequent processing steps, thereby improving oxidation resistance without requiring high nitrogen concentration in the final nitride layer.
2Reliability
If oxidation process is performed to recover etching damage on polysilicon film sidewall, then etching damage is recovered, but excessive oxidation of polysilicon film occurs
Solution Approach 1:
The patent applies preliminary anti-action by forming a nitride layer on the polysilicon film before performing the oxidation process. This nitride layer acts as a protective barrier that counteracts the harmful effect of excessive oxidation while allowing the oxidation process to recover etching damage. The nitride layer prevents oxygen from penetrating into and excessively oxidizing the polysilicon film sidewalls.
3Quantity of substance
If substrate is exposed to atmosphere before nitride layer formation, then oxygen-containing layer (native oxide) is formed on substrate, but this hinders formation of high nitrogen concentration nitride layer
Solution Approach 1:
The patent converts the harmful effect of the oxygen-containing layer (native oxide) into a beneficial feature. Instead of removing the native oxide layer before nitride layer formation, the patent performs oxidation first to deliberately form or enhance the oxygen-containing layer, then forms the nitride layer on top of it. This approach simplifies the manufacturing process by eliminating the need for additional cleaning steps while still achieving the desired nitride layer with sufficient oxidation protection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the oxidation resistance of polysilicon films, preventing bird beak formation and improving the input and erasing characteristics of semiconductor devices by forming a nitride layer with high nitrogen concentration, thus maintaining device reliability.
Implementation Method 1
heating the substrate to a predetermined temperature using the heating unit
Implementation Method 2
exciting the process gas supplied by the gas supply unit using the excitation unit
Implementation Method 3
modifying the oxygen-containing layer into an oxynitride layer or a nitride layer by heating the substrate and exciting the process gas
Data Source
AI summary
To inhibit excessive oxidation and increase oxidation resistance of a polysilicon film on a substrate during recovery process, an oxygen-containing silicon layer present on the substrate is modified into a silicon oxynitride layer or a silicon nitride layer with high nitrogen concentration prior to the recovery process by heating the substrate and supplying active species containing nitrogen radicals and hydrogen radicals for increasing nitrogen content in the silicon oxynitride layer or the silicon nitride layer.