Molybdenum Layer Deposition With Underlayer Stress Control
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Solution Overview
Problem
Conventional methods face challenges in finding suitable conducting materials for metal gap fill and liner applications in semiconductor devices that exhibit desired properties such as effective resistivity, low deposition temperature, and tunable film stress.
Innovation Solution
A method involving the formation of a transition metal underlayer, such as a transition metal sulfide, carbide, or nitride, followed by a molybdenum layer deposition using a cyclical process at low temperatures, allowing for stress manipulation and reduced impurity concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional deposition methods are used for molybdenum layers, then deposition temperature can be reduced, but film stress control and impurity concentration become problematic
Solution Approach 1:
A chromium underlayer is introduced as an intermediary between the substrate and the molybdenum layer. This underlayer acts as a mediator that enables low-temperature molybdenum deposition while providing the necessary surface properties for stress control and nucleation, thus resolving the contradiction between low deposition temperature and film stress control
Solution Approach 2:
The patent employs a composite structure consisting of a chromium underlayer combined with a molybdenum layer. This composite material approach allows the system to benefit from the low-temperature deposition capability enabled by the chromium layer while achieving proper stress control and film quality in the molybdenum layer
2Temperature
If conventional deposition methods are used for molybdenum layers, then deposition temperature can be reduced, but impurity concentration increases
Solution Approach 1:
The chromium underlayer serves as an intermediary that facilitates low-temperature deposition while preventing impurity incorporation in the molybdenum layer. It provides a clean interface and controlled nucleation environment that maintains film purity even at reduced deposition temperatures
3Manufacturing precision
If a transition metal underlayer is formed, then molybdenum layer stress and nucleation are improved, but process complexity increases
Solution Approach 1:
The chromium underlayer is a simple, well-established material that provides excellent nucleation properties for molybdenum. By using this proven intermediary, the patent achieves improved nucleation and film quality without introducing excessive process complexity, as the chromium layer can be deposited using standard PVD or CVD techniques already common in semiconductor manufacturing
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
Enables the deposition of molybdenum layers with controlled stress and low impurities, suitable for gap fill, liner, and interconnect applications in semiconductor devices, while maintaining low deposition temperatures.
Implementation Method 1
forming a molybdenum layer overlying the underlayer, wherein the step of forming the molybdenum layer includes a cyclic deposition process
Data Source
AI summary
Methods and systems for forming molybdenum layers on a surface of a substrate and structures and devices formed using the methods are disclosed. Exemplary methods include forming an underlayer prior to forming the molybdenum layer. The underlayer can be used to manipulate stress in the molybdenum layer and/or reduce a nucleation temperature and/or deposition temperature of a step of forming the molybdenum layer.