Bottom-Up Metal Gap Fill for High-Aspect-Ratio Features
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Solution Overview
Problem
Current semiconductor fabrication processes face challenges in effectively filling gap features on non-planar substrates with a metal film, particularly in high aspect ratio features, due to limitations in existing deposition methods such as HDP, SACVD, and LPCVD.
Innovation Solution
A method involving a cyclic deposition-etch process is employed, where a first material layer is deposited into the gap feature, etched to form a base, and then partially filled with a second material layer, utilizing specific precursors and halides to achieve selective bottom-up fill deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods (HDP, SACVD, LPCVD) are used to fill gap features, then the process is simple and straightforward, but the gap fill capability is insufficient and voids form in high aspect ratio features
Solution Approach 1:
The deposition process is segmented into multiple cyclic steps including deposition of first material layer, etching to form base, and partial filling with second material layer. This segmentation allows precise control over material deposition in high aspect ratio gap features, eliminating voids while maintaining process manageability through automated cyclic execution
Solution Approach 2:
The patent employs periodic cyclic deposition-etching actions where material is deposited, etched back, and redeposited in repeated cycles. This periodic action enables bottom-up fill mechanism that progressively builds material from the base of gap features upward, ensuring complete filling without voids in high aspect ratio structures
2Manufacturing precision
If cyclic deposition-etch process is used to achieve bottom-up fill, then gap fill capability is improved, but the process complexity increases
Solution Approach 1:
A base layer (first material layer) is introduced as an intermediary structure that facilitates selective bottom-up deposition of the second material layer. This base acts as a mediator enabling controlled material growth from the bottom of gap features, ensuring uniform filling while the cyclic automation manages process complexity
Solution Approach 2:
The process creates local quality differences by forming a base at the bottom of gap features with specific material properties, then selectively depositing second material layer only in regions where the base exists. This local differentiation enables precise control over filling uniformity in high aspect ratio features
3Reliability
If gap features are filled with metal film, then electrical properties are improved, but voids and impurities increase with conventional methods
Solution Approach 1:
The patent replaces conventional mechanical/thermal deposition mechanisms with a chemically-driven cyclic deposition-etch process. This substitution enables precise atomic-level control over material placement, filling gap features completely without voids or impurities, thereby improving electrical properties and reliability of semiconductor devices
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 improved filling of gap features with a metal film, enhancing the electrical properties of semiconductor devices by reducing resistivity and minimizing voids and impurities, thus addressing the limitations of existing gap fill processes.
Implementation Method 1
depositing a first material layer into the gap feature with a first cyclic deposition process
Implementation Method 2
etching the first material layer to form a base in a bottom portion of the gap feature with a cyclic etching process
Data Source
AI summary
Disclosed is a method, system and apparatus for filling a gap feature on a substrate surface, comprising providing a substrate with a surface comprising a gap feature in a reaction chamber, depositing a first material layer into the gap feature with a first cyclic deposition process, etching the first material layer to form a base in a bottom portion of the gap feature with a cyclic etching process and partially filling the gap feature with a second material layer with a second cyclic deposition process.