Gate Electrode Contact Formation After Plasma Residue Removal
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable contacts to source/drain regions in finFET devices due to the presence of polymeric residues and etch by-products, which can degrade contact quality and increase resistance.
Innovation Solution
A post-etch treatment using a plasma formed from a gas mixture of oxygen and hydrogen, without nitrogen, is applied to remove these residues and by-products, followed by a bottom-up deposition process to form gate electrode contacts, preventing seam formation and improving growth height and incubation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etching processes are used to form contact openings, then contact openings can be formed, but polymeric residues and etch by-products remain that degrade contact quality and increase resistance
Solution Approach 1:
The patent applies a plasma treatment process using oxygen and hydrogen gases to convert the harmful polymeric residues and etch by-products into volatile compounds that can be removed. The plasma chemistry transforms the contaminants into removable species, effectively converting the harmful effect of residues into a beneficial cleaning action that improves contact quality and reduces resistance.
Solution Approach 2:
The patent changes the chemical parameters of the etching environment by introducing a nitrogen-free plasma environment. By controlling the plasma composition (oxygen and hydrogen gases only) and processing conditions, the chemical state of the contact opening surfaces is modified to prevent residue formation and enable cleaner contact formation, thereby improving contact reliability.
2Ease of manufacture
If nitrogen-containing environments are used during contact formation, then processing can be simplified, but nitrogen contamination increases which degrades contact growth quality
Solution Approach 1:
The patent employs a nitrogen-free plasma environment (using only oxygen and hydrogen gases) during the contact formation process. This inert-like atmosphere prevents nitrogen contamination of the contact openings, ensuring high-purity contact growth. The controlled gas environment maintains processing simplicity while eliminating nitrogen-related quality degradation.
3Reliability
If bottom-up deposition is used to form contacts, then seam formation is prevented, but incubation time and growth height control become critical parameters
Solution Approach 1:
The patent applies plasma treatment to the contact openings before initiating the bottom-up deposition process. This preliminary cleaning and activation of the substrate surface prepares the openings for optimal contact nucleation and growth, reducing the incubation time required for contact formation. The pre-treatment ensures uniform contact growth by eliminating surface contaminants that would otherwise delay the deposition process.
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 removes polymeric residues and etch by-products, maintaining a low nitrogen profile and achieving improved contact growth heights and reduced incubation times, enhancing contact reliability and performance.
Implementation Method 1
performing a post etching treatment wherein the post etching treatment includes forming a plasma comprising oxygen and hydrogen
Implementation Method 2
forming a plasma comprising oxygen and hydrogen, wherein the plasma does not include nitrogen
Implementation Method 3
performing a bottom-up deposition process to fill the first opening
Data Source
AI summary
Semiconductor devices and methods of manufacturing the semiconductor devices are described herein. A method includes forming a gate electrode, a gate electrode contact layer over the gate electrode, forming a dielectric layer over the gate electrode contact layer, and performing an etch through the dielectric layer, the etch forming an opening that exposes the gate electrode contact layer. The method further includes performing a post-etch treatment on the opening formed by the etch process by exposing the opening to a plasma. The method further includes forming gate electrode contacts in the openings after the post-etch treatment by a bottom-up deposition process.