UV Irradiation for Semiconductor Etch Residue Removal
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Solution Overview
Problem
In semiconductor manufacturing, the build-up of by-product residues during plasma processing of substrates leads to tapered vias or contact opening profiles, hindering etch performance and causing electrical issues due to reduced conductor sizes or clogged openings.
Innovation Solution
Irradiating substrates with ultra-violet radiation of wavelengths between 100 nm and 200 nm to weaken the chemical bonds of by-product residues, facilitating their removal and improving etch process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma processing is used to etch substrates, then etching performance is improved, but by-product residues build up causing tapered profiles
Solution Approach 1:
The patent converts the harmful by-product residues into removable compounds by exposing them to UV radiation. The UV light breaks down the polymer residues into volatile compounds that can be easily removed, transforming the harmful buildup into a beneficial cleaning effect that restores vertical via profiles
Solution Approach 2:
The patent introduces UV radiation as an intermediary between the plasma etching process and the final cleaned substrate. This intermediary step breaks down the complex polymer residues into simpler volatile compounds, facilitating their removal without affecting the underlying substrate or previously formed structures
2Manufacturing precision
If by-product residues are removed, then opening profiles are improved, but additional process steps are required
Solution Approach 1:
The patent merges the cleaning function into the existing plasma processing sequence by inserting UV exposure between etching steps. This combines multiple functions (etching and residue removal) into a unified process flow, eliminating the need for separate cleaning operations and reducing overall process complexity
Solution Approach 2:
The patent performs preliminary UV exposure to break down residues before subsequent etching steps complete. This preliminary action prevents residue buildup from affecting final profile quality, eliminating the need for post-processing cleaning steps
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
The use of ultra-violet radiation effectively breaks chemical bonds in by-product residues, allowing for their easy removal and maintaining good opening profiles, thus enhancing etch performance and preventing electrical issues.
Implementation Method 1
performing an irradiation process to irradiate the substrate with ultra-violet radiation having a wavelength between 100 nm and 200 nm
Data Source
AI summary
A method for processing a substrate includes performing a first etch process to form a plurality of partial features in a dielectric layer disposed over the substrate; performing an irradiation process to irradiate the substrate with ultra-violet radiation having a wavelength between 100 nm and 200 nm; and after the irradiation process, performing a second etch process to form a plurality of features from the plurality of partial features.