Selective Thin-Film Hardness for Crack-Resistant Gapfill
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Solution Overview
Problem
Silicon oxide layer cracking occurs in the 25 μm SiO inter-die gapfill process flow due to thermal and mechanical stress during grinding and chemical mechanical polishing, leading to instability in thin film processing.
Innovation Solution
A method is developed to deposit a fill layer with varying hardness across different regions of a substrate, where the sidewall region has a lower hardness than the field and fill regions, using controlled chemical vapor deposition processes to mitigate mechanical and thermal stresses, thereby preventing cracking during subsequent planarization processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform hardness layer is deposited across all regions, then the manufacturing process is simple, but cracking occurs during mechanical processing due to thermal and mechanical stress
Solution Approach 1:
The patent applies local quality by creating different hardness characteristics in different regions of the deposited layer. The sidewall region is engineered to have lower hardness compared to the field and fill regions. This is achieved through controlled deposition processes that create a hardness gradient, making the sidewall region more compliant and less prone to cracking during mechanical processing while maintaining structural integrity in other areas.
2Strength
If the layer hardness is reduced to prevent cracking, then mechanical stress resistance improves, but the layer strength and structural integrity deteriorate
Solution Approach 1:
The invention resolves this contradiction by applying local quality - different regions of the layer have different hardness properties tailored to their specific functional requirements. The sidewall region has reduced hardness for crack resistance during mechanical processing, while the field and fill regions maintain higher hardness for structural integrity and strength.
Solution Approach 2:
The layer is effectively segmented into different functional zones with distinct mechanical properties. The sidewall region is separated in terms of mechanical characteristics from the field and fill regions, allowing each segment to optimize for its specific role - the sidewall for stress compliance and the other regions for structural support.
3Manufacturing precision
If a harder layer is deposited to maintain structural integrity, then layer strength improves, but cracking during mechanical processing increases
Solution Approach 1:
The patent eliminates the need for uniform hardness by implementing local quality variations. The sidewall region is specifically engineered with lower hardness to absorb mechanical stresses during processing, preventing crack propagation, while other regions maintain higher hardness for structural purposes. This localized property differentiation resolves the contradiction between uniformity and stress resistance.
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 approach effectively reduces or eliminates cracking in the fill layer during mechanical processing, maintaining stability and throughput without increasing costs, and is applicable in inter-die gapfill and 3D packaging applications.
Implementation Method 1
a method of processing a substrate comprises depositing a layer in a processing chamber on a field region, a sidewall region, and a fill region of a feature of the substrate
Implementation Method 2
reducing a thickness of at least a portion of the substrate via chemical mechanical planarization
Data Source
AI summary
A method of processing a substrate is disclosed which includes depositing a layer in a processing chamber on a field region, a sidewall region, and a fill region of a feature of the substrate, wherein a hardness of a portion of the layer deposited on the sidewall region is lower than a hardness of a portion of the layer deposited on the field region, and lower than a hardness of a portion of the layer deposited on the fill region.