Selective ALD Metal Deposition on Silicon Without Global Growth
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Solution Overview
Problem
Conventional selective deposition processes struggle to reliably form metal-containing materials on small, high-aspect-ratio structures in semiconductor manufacturing, often resulting in undesired material formation on non-target locations due to lack of selectivity and precision, leading to cross-contamination and reduced circuit density and quality.
Innovation Solution
An atomic layer deposition (ALD) process is employed, pulsing metal and silicon-containing precursors alternately to selectively form a metal-containing material on specific substrate materials, followed by thermal annealing, maintaining a substrate temperature below 150 degrees Celsius to ensure precise deposition and prevent thermal decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional selective deposition process is used, then deposition speed and coverage are improved, but selectivity and precision deteriorate, resulting in undesired material formation on non-target locations
Solution Approach 1:
The patent employs periodic pulsing of precursor gases in alternating cycles. The metal-containing precursor is pulsed for a specific duration to deposit metal atoms, followed by a purge step, then a silicon-containing precursor is pulsed to deposit silicon atoms. This periodic action allows precise control over material deposition timing and location, achieving both high productivity and selectivity by ensuring materials are deposited only when and where intended.
Solution Approach 2:
The deposition process is segmented into distinct sequential steps: metal precursor pulsing, purging, silicon precursor pulsing, and purging. Each step is independently controlled with specific timing parameters. This segmentation enables precise control over where and what material is deposited, preventing cross-contamination while maintaining efficient deposition rates through optimized cycle times.
2Productivity
If deposition temperature is increased to improve deposition rate, then productivity is improved, but thermal decomposition and loss of selectivity occur
Solution Approach 1:
The patent utilizes parameter changes by adjusting precursor pulse durations, purge times, and substrate temperature within optimized ranges. By carefully controlling these parameters—particularly maintaining substrate temperature below 150°C while optimizing precursor exposure times—the process achieves acceptable deposition rates without causing thermal decomposition or losing selectivity. The parameter optimization balances productivity and material stability.
3Area of stationary object
If global deposition is performed to ensure complete coverage, then coverage is improved, but cross-contamination and loss of selectivity occur
Solution Approach 1:
The patent introduces purge gas as an intermediary between precursor pulsing steps. The purge gas flows across the substrate surface to remove excess precursor molecules and reaction byproducts before the next precursor is introduced. This intermediary action prevents cross-contamination between metal and silicon deposition steps while ensuring complete coverage of target areas through controlled material transport.
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 method enables the selective and precise formation of metal-containing layers on silicon surfaces while avoiding deposition on insulating materials, enhancing the accuracy and reliability of semiconductor manufacturing by maintaining selectivity and preventing global deposition, thus improving circuit density and quality.
Implementation Method 1
An atomic layer deposition (ALD) process is employed, pulsing metal and silicon-containing precursors alternately to selectively form a metal-containing material on specific substrate materials
Implementation Method 2
followed by thermal annealing, maintaining a substrate temperature below 150 degrees Celsius to ensure precise deposition and prevent thermal decomposition
Data Source
AI summary
Methods for depositing a metal containing material formed on a certain material of a substrate using an atomic layer deposition process for semiconductor applications are provided. In one embodiment, a method of forming a metal containing material on a substrate comprises pulsing a first gas precursor comprising a metal containing precursor to a surface of a substrate, pulsing a second gas precursor comprising a silicon containing precursor to the surface of the substrate, forming a metal containing material selectively on a first material of the substrate, and thermal annealing the metal containing material formed on the substrate.