Void-Free Metal Fill by Sidewall Inhibition in Deep Features
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Deposition of void-free and low-stress conductive films, such as tungsten, in deep features and complex semiconductor structures is challenging due to the difficulty in preventing precursor consumption at the feature top, leading to incomplete filling and void formation.
Innovation Solution
A method involving a conformal metal deposition followed by inhibition operations to prevent sidewall nucleation, allowing the precursor to diffuse to the feature bottom, with repeated inhibition and deposition cycles at high temperatures to ensure complete filling without stress, using a process chamber with controlled gas flow and temperature management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conformal metal deposition is performed in deep features, then the feature walls are uniformly coated, but precursor consumption at the feature top leads to incomplete filling and void formation
Solution Approach 1:
The patent applies preliminary anti-action by depositing a sacrificial material layer on the feature walls before metal deposition. This sacrificial layer prevents precursor consumption at the feature top during subsequent deposition steps, allowing complete filling without void formation. The sacrificial layer is removed after filling to leave a void-free metal structure.
Solution Approach 2:
The patent performs preliminary action by first depositing a conformal metal layer, then applying inhibition species to block sidewall nucleation before the main fill deposition. This preliminary inhibition action ensures that precursor reaches the feature bottom without being consumed at the top, enabling complete filling.
2Manufacturing precision
If inhibition species are applied to prevent sidewall nucleation, then complete filling is achieved, but the process complexity increases with multiple inhibition and deposition cycles
Solution Approach 1:
The patent employs periodic action by repeating cycles of inhibition species deposition and metal deposition. Each cycle consists of applying inhibition species to block sidewall nucleation, followed by metal deposition to advance the fill. This periodic repetition continues until complete filling is achieved, ensuring fill completeness while maintaining process control.
3Stress or pressure
If high temperature deposition is used to reduce stress, then low stress films are obtained, but the thermal budget increases
Solution Approach 1:
The patent applies parameter changes by conducting metal deposition at elevated substrate temperatures (e.g., ≥400°C). This temperature parameter change reduces intrinsic stress in the deposited metal films, producing low-stress films suitable for semiconductor interconnects. The high temperature promotes stress relaxation during 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 enables the deposition of high-quality, void-free, and low-stress metal films in deep features, ensuring effective filling and reducing the risk of void formation, thereby improving the reliability of semiconductor interconnects and feature fill processes.
Implementation Method 1
depositing a conformal layer of metal in the vertically-oriented feature
Implementation Method 2
exposing the conformal layer of metal feature to inhibition species at first flow rate and first exposure time in a first inhibition operation
Implementation Method 3
preferentially depositing metal at the bottom of the vertically-oriented feature in a first non-conformal deposition operation
Implementation Method 4
a temperature of the substrate is at least 400° C. during the first non-conformal deposition operation
Data Source
AI summary
Provided herein are methods of depositing low stress and void free metal films in deep features and related apparatus. Embodiments of the methods include treating the sidewalls of the holes to inhibit metal deposition while leaving the feature bottom untreated. In subsequent deposition operations, metal precursor molecules diffuse to the feature bottom for deposition. The process is repeated with subsequent inhibition operations treating the remaining exposed sidewalls. By repeating inhibition and deposition operations, high quality void free fill can be achieved. This allows high temperature, low stress deposition to be performed.