Selective Molybdenum Bottom-Up Fill for Void-Free Features
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Solution Overview
Problem
The challenge in semiconductor fabrication is achieving uniform deposition of low resistivity metal films, particularly as devices shrink and more complex patterning schemes are used, leading to difficulties in filling patterned features with metals like molybdenum.
Innovation Solution
The method involves selective deposition of molybdenum (Mo) films on the bottom metal-containing surfaces of features, including dielectric sidewalls, using atomic layer deposition (ALD) with molybdenum-containing oxyhalide precursors and a reducing agent, allowing for bottom-up growth and void-free fill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition methods are used to fill patterned features with molybdenum, then deposition coverage is achieved, but uniformity and void-free fill deteriorate as devices shrink and patterning complexity increases
Solution Approach 1:
The patent employs selective deposition where molybdenum is deposited preferentially on metal-containing surfaces (such as seed layers at the bottom of features) compared to dielectric sidewalls. This local quality difference in deposition rate enables uniform bottom-up fill without voids, even in complex high-aspect-ratio structures, resolving the contradiction between achieving coverage and maintaining uniformity under complex patterning conditions
2Reliability
If selective deposition on bottom metal-containing surfaces is implemented, then void-free fill is achieved, but process complexity increases
Solution Approach 1:
The patent utilizes parameter changes in the ALD process, specifically adjusting temperature and precursor selection, to achieve selective deposition on metal surfaces versus dielectric surfaces. By controlling deposition temperature and using appropriate precursors, the process achieves bottom-up void-free fill through selective growth, managing process complexity while ensuring high reliability of feature 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
This approach enables high-quality, void-free filling of patterned features with molybdenum, achieving low resistivity and improved electrical connectivity in semiconductor devices.
Implementation Method 1
performing multiple cycles of an atomic layer deposition (ALD) process to selectively deposit a molybdenum (Mo) film on the metal-containing surface relative to the oxide or nitride surfaces
Implementation Method 2
the ALD process includes exposing the feature to alternate pulses of molybdenum-containing oxyhalide precursor and a reducing agent
Implementation Method 3
the method also includes, prior to performing the multiple cycles of the ALD deposition process, exposing the metal-containing surface to a hydrogen-containing plasma
Data Source
AI summary
Provided are methods of filling patterned features with molybdenum (Mo). The methods involve selective deposition of Mo films on bottom metal-containing surfaces of a feature including dielectric sidewalls. The selective growth of Mo on the bottom surface allows bottom-up growth and high quality, void-free fill. Also provided are related apparatus.