Selective Metal Capping for Seamless Semiconductor Contact Fill
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Solution Overview
Problem
Conventional methods for forming contact structures in semiconductor devices often result in high resistance due to seam formation during the filling process, leading to reduced performance of packaged semiconductor structures.
Innovation Solution
A method involving a preclean operation, followed by a bottom-up super-conformal deposition of a metal fill layer into a feature on a semiconductor structure, utilizing a metal halide precursor to selectively remove layers and achieve a seamless fill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional conformal deposition process is used to fill the feature, then the feature can be filled with metal layer, but a seam is formed during the filling process which causes significant line resistance increase
Solution Approach 1:
The patent segments the deposition process into multiple cycles, each depositing a portion of the final metal fill thickness. By dividing the fill into sequential segments rather than a single conformal deposition, the process eliminates seam formation while maintaining complete feature filling. Each cycle deposits metal on the bottom and sidewalls, and subsequent cycles build upon previous layers without creating interfaces that would form seams.
Solution Approach 2:
The patent employs periodic action through cyclic repetition of the metal deposition process. Multiple deposition cycles are performed sequentially, with each cycle contributing a portion of the final fill thickness. This periodic repetition allows progressive building of the metal fill from bottom to top, ensuring complete coverage without seam formation and reducing line resistance through seamless integration of deposited layers.
2Quantity of substance
If conventional silicide formation process is used, then metal layer can be deposited on bottom, sidewalls and field regions, but this leads to seam formation in the feature
Solution Approach 1:
The patent segments the metal deposition into multiple thin layers through cyclic processes, where each cycle deposits a controlled thickness of metal on the bottom, sidewalls, and field regions. This segmentation prevents the formation of seams by building the fill progressively, ensuring uniform coverage across all regions without the defects associated with single-step conventional silicide formation.
3Ease of manufacture
If traditional W conformal deposition process is used, then the contact structure can be filled, but seam formation occurs which reduces connection reliability
Solution Approach 1:
The patent applies periodic action by repeating the conformal deposition cycle multiple times, with each cycle contributing a portion of the final fill. This periodic repetition maintains the simplicity of conformal deposition while eliminating seam formation, thereby preserving ease of manufacture while significantly improving connection reliability through seamless fill.
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 method effectively reduces line resistance and ensures reliable contact structures by achieving a super-conformal metal fill profile, thereby enhancing the overall performance of semiconductor devices.
Implementation Method 1
introducing a metal halide precursor to the deposited contact structure to at least partially remove the second layer from the deposited contact structure
Implementation Method 2
depositing a metal fill layer onto the first layer to form a filled contact structure. The deposited metal fill layer comprises a super conformal profile
Data Source
AI summary
Embodiments of the present disclosure generally relate to methods and processes for selectively depositing a metal fill layer into a feature on the surface of a semiconductor structure. In some embodiments, a method of forming a contact structure includes performing a preclean operation on a contact structure to form a precleaned contact structure. The contact structure includes a silicon-based portion exposed in a cavity of a substrate. The method further includes depositing a metal layer over the precleaned contact structure to form a deposited contact structure. The method further includes introducing a metal halide precursor to the deposited contact structure to at least partially remove the second layer from the deposited contact structure to form an etched contact structure. The method further includes depositing a metal fill layer onto the first layer to form a filled contact structure. The deposited metal fill layer comprises a super conformal profile.