Metal Wiring Oxidation Etching With In-Situ Oxide Reduction
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Solution Overview
Problem
The challenge is to etch metal wiring portions on a substrate using oxidation while minimizing the increase in resistance value due to the oxide film formed during the process.
Innovation Solution
A method involving a substrate processing apparatus that alternates between supplying an oxidizing gas to etch the metal wiring portion and a reducing gas to reduce the oxide film, with a barrier film etched to maintain distance and reduce resistance, using gases like ozone and hydrogen, and controlling temperature and gas concentrations to optimize etching and reduction processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an oxidizing gas is supplied to etch the metal wiring portion, then the etching process is effective, but an oxide film is formed on the metal wiring portion causing increased resistance value
Solution Approach 1:
The patent applies periodic action by alternately supplying oxidizing gas and reducing gas in a cyclic manner. The oxidizing gas etches the metal wiring portion while temporarily forming an oxide film, then the reducing gas removes the oxide film. This periodic alternation allows continuous etching progress while preventing resistance increase, as each oxidation cycle is followed by a reduction cycle that restores the metal surface.
Solution Approach 2:
The patent changes the chemical state parameters of the gas environment by switching between oxidizing conditions (supplying oxidizing gas) and reducing conditions (supplying reducing gas). This parameter change allows the same metal wiring portion to undergo alternating oxidation and reduction, achieving etching without permanent oxide film formation that would increase resistance.
2Reliability
If the upper surface of the metal film is etched to retract further than the insulating film surface, then the distance between via and metal film is maintained, but the metal wiring portion shape requires adjustment
Solution Approach 1:
The patent replaces traditional mechanical or physical etching methods with chemical etching using oxidizing gas. This substitution allows for more precise and uniform etching of the metal wiring portion surface, achieving the required retraction distance while maintaining wiring shape control through chemical reaction uniformity rather than mechanical variability.
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 effectively reduces the resistance value of the metal wiring portion by restoring the oxide film to its original metal state, preventing increased resistance and ensuring accurate etching control, thereby improving semiconductor device performance.
Implementation Method 1
an etching step of supplying an oxidizing gas to the substrate to etch one part of the metal wiring portion
Implementation Method 2
a reducing step of supplying a reducing gas to the substrate to reduce an oxide film of the metal wiring portion formed by the etching step
Data Source
AI summary
A wiring forming method includes a loading step (Si), an etching step (S3), and a reducing step (S6). In the loading step (S1), a substrate having a metal wiring portion formed thereon is loaded into a chamber. In the etching step (S3), an oxidizing gas is supplied to the substrate to etch one part of the metal wiring portion. In the reducing step (S6), a reducing gas is supplied to the substrate to reduce an oxide film of the metal wiring portion formed by the etching step (S3).