Multi-step Deposition Control for Barrier Metal Step Coverage
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Solution Overview
Problem
In integrated circuit manufacturing, achieving uniform and thin barrier metal layers in high aspect ratio contact holes is challenging due to material overhang at the shoulder and inadequate bottom step coverage, which affects adhesion and diffusion prevention between metal and dielectric layers.
Innovation Solution
A multi-step deposition technique is employed, using different sets of process parameters for each sub-process, where the actual value of a process parameter is generated by considering its previous value, allowing for controlled sputter and re-sputter processes to improve step coverage and layer thickness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin barrier metal layer is deposited to reduce resistance, then the electrical resistance decreases, but the step coverage and adhesion at bottom corners deteriorate
Solution Approach 1:
The deposition process is divided into multiple sequential sub-processes, each with optimized parameters for specific regions. The first sub-process deposits material with parameters optimized for bottom corner coverage, while subsequent sub-processes add material to reach target thickness on sidewalls and tops, ensuring both adhesion at corners and uniform thickness overall
Solution Approach 2:
The patent dynamically adjusts deposition parameters between sub-processes. By changing parameters such as deposition rate, plasma power, and gas flow ratios between sub-processes, the system adapts to deposit material differently on various surfaces (bottom corners vs. sidewalls vs. tops), achieving both good step coverage and thickness uniformity
2Reliability
If material is deposited to cover sidewalls adequately, then step coverage improves, but material overhang at shoulder increases
Solution Approach 1:
The deposition is segmented into sub-processes where the first sub-process focuses on achieving adequate coverage at the bottom and middle sections of sidewalls. Subsequent sub-processes then deposit additional material that fills in the shoulder region without creating excessive overhang, as each sub-process targets specific regions with optimized parameters
Solution Approach 2:
The patent uses periodic deposition cycles with alternating parameter sets. Each cycle deposits material with specific parameters, then pauses to allow for parameter adjustment. This periodic action enables the system to build up coverage progressively while controlling overhang by varying deposition conditions between cycles
3Manufacturing precision
If a multi-step deposition process is used to improve uniformity, then manufacturing precision improves, but process complexity increases
Solution Approach 1:
Multiple deposition sub-processes are merged into a single continuous deposition sequence within one chamber. By combining the advantages of different deposition conditions in one integrated process, the system achieves high uniformity without requiring multiple separate processing steps, thereby reducing overall process complexity
Solution Approach 2:
The patent achieves improved uniformity through controlled parameter changes between sub-processes rather than through complex process structures. By systematically varying parameters like deposition rate and plasma conditions, the system obtains precise thickness control with a relatively simple multi-step approach
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 enhances the uniformity and thickness of barrier metal layers on sidewalls and bottom corners, improving adhesion and preventing undue interaction between metal and dielectric layers, thereby increasing the reliability and efficiency of the deposition process.
Implementation Method 1
a plurality of different material layers are deposited on each other and patterned to define required device features
Implementation Method 2
deposition techniques
Implementation Method 3
a second set of process parameters defining a re-sputter process, wherein part of the deposited material is removed from the wafer
Data Source
AI summary
For providing control of two-step or a multi-step deposition process, a method and a corresponding deposition system is provided comprising providing a deposition process having at least two sub-processes employing different sets of process parameters, wherein each set of process parameters comprises at least one process parameter. The method comprises controllably generating an actual value for at least one first process parameter by taking into account at least one previous value of the respective first process parameter, wherein each first process parameter is a process parameter of said at least two sets of process parameters.