TaN Barrier Layer Deposition With Dynamic Coil Field Control
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Solution Overview
Problem
As semiconductor devices continue to integrate more components into smaller areas, challenges arise in the deposition processes, particularly in forming conformal barrier layers within interconnect structures, where existing methods struggle to achieve uniform coverage and sufficient film density while avoiding defects like overhangs and insufficient sidewall coverage.
Innovation Solution
A physical vapor deposition process using multiple coils to adjust the electromagnetic field and separation distances during the deposition of tantalum nitride barrier layers, combined with atomic layer deposition, to achieve a gradient composition and improved conformality, resulting in higher film density and uniform coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If physical vapor deposition is used to form barrier layers, then deposition speed and film density are improved, but conformality and uniform coverage are insufficient
Solution Approach 1:
The patent employs dynamic adjustment of coil separation distances during the deposition process. The coils are positioned at different distances from the substrate at different stages: initially closer to achieve rapid deposition, then moved farther to improve conformality. This dynamic repositioning allows the system to transition between high-speed deposition mode and high-conformality mode, resolving the contradiction between deposition speed and conformality.
Solution Approach 2:
The deposition process is divided into multiple periodic stages with alternating objectives. First, a seed layer is deposited with coils at a first separation distance to establish initial coverage. Then, the coils are repositioned to a second separation distance for subsequent barrier layer deposition to enhance conformality. This periodic alternation between deposition conditions allows the system to achieve both high speed and high precision at different phases of the same process.
2Ease of manufacture
If conventional deposition methods are used, then process simplicity is maintained, but film density and uniform coverage are insufficient
Solution Approach 1:
The system maintains relative simplicity by using a single deposition chamber and standard PVD equipment, avoiding the need for complex multi-chamber systems or alternative deposition methods. The enhanced film density and uniform coverage are achieved through dynamic coil repositioning within the existing system, preserving ease of manufacture while significantly improving manufacturing precision.
3Device complexity
If single coil configuration is used, then device complexity is reduced, but conformality and coverage uniformity are poor
Solution Approach 1:
The electromagnetic field generation is segmented into multiple independent coils rather than using a single coil. This segmentation allows each coil to be independently positioned at optimal distances from different regions of the substrate, enabling precise control over the deposition pattern. The multiple coils work in coordination to achieve uniform coverage and improved conformality while maintaining manageable system complexity through modular design.
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 solution achieves a conformal barrier layer with a tantalum to nitrogen ratio greater than 0.9, film density greater than 13 g/cm3, and a thickness ratio of greater than 0.7 across sidewalls and the bottom, enhancing the semiconductor device's performance by maintaining the benefits of physical vapor deposition while achieving ALD-like coverage.
Implementation Method 1
during the sputtering the first portion of the barrier material a first coil is situated a first distance away from the mounting platform
Implementation Method 2
A physical vapor deposition process using multiple coils to adjust the electromagnetic field and separation distances during the deposition of tantalum nitride barrier layers
Data Source
AI summary
A semiconductor device is manufactured by modifying an electromagnetic field within a deposition chamber. In embodiments in which the deposition process is a sputtering process, the electromagnetic field may be modified by adjusting a distance between a first coil and a mounting platform. In other embodiments, the electromagnetic field may be adjusted by applying or removing power from additional coils that are also present.