Back Side Film Stack Stress Tuning for Bonding Warpage Control
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Solution Overview
Problem
The semiconductor industry faces challenges in bonding and packaging processes due to increasing warpage in SOC substrates, which degrades the SoIC chip-on-substrate process window and results in low bond yield, and existing back side dielectric films do not provide sufficient protection during processing.
Innovation Solution
A method involving the deposition of back side dielectric films on both sides of semiconductor substrates in a batch processing chamber, with specific characteristics such as stress level and thickness determined by bonding chemistry and packaging scheme, to protect devices and adjust substrate warpage during bonding and packaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If back side dielectric films are deposited to protect devices during bonding and packaging, then device protection and adhesion are improved, but substrate warpage increases due to additional metal layers in BEOL processing
Solution Approach 1:
The patent modifies the physical and chemical parameters of the back side dielectric films, specifically controlling stress level (compressive or tensile) and thickness, to counteract warpage caused by BEOL metal layers while maintaining device protection during bonding and packaging processes
Solution Approach 2:
The patent employs composite dielectric film structures on the back side of substrates, combining multiple layers with different material properties to simultaneously achieve device protection, adhesion enhancement, and warpage compensation in advanced packaging applications
2Productivity
If more metal layers are added in advanced BEOL processing to increase integration density, then component integration is improved, but substrate warpage becomes higher degrading SoIC process window
Solution Approach 1:
The patent applies preliminary counter-actions by depositing back side dielectric films with specific stress characteristics before bonding processes to preemptively compensate for warpage that would otherwise be caused by subsequent BEOL metal layer additions, thereby maintaining process window for SoIC chip-on-substrate applications
3Reliability
If back side dielectric films with specific stress and thickness are deposited to adjust warpage, then bonding yield is improved, but processing complexity increases due to batch processing requirements
Solution Approach 1:
The patent combines multiple functions into a single batch processing step, where back side dielectric films are deposited alongside front side structures in the same processing chamber, simultaneously achieving device protection, warpage adjustment, and adhesion enhancement without requiring separate processing steps
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 proposed method effectively reduces warpage and enhances protection during bonding, improving yield and adhesion in both wafer-to-wafer and die-to-die bonding processes, particularly in advanced packaging schemes like CoWoS and SoIC.
Implementation Method 1
A method involves depositing back side dielectric films on both sides of semiconductor substrates in a batch processing chamber
Data Source
AI summary
Embodiments of the present disclosure relate to methods for forming a film stack during fabrication or bonding process. The film stack according to present disclosure may reduce wet dip attacking to semiconductor substrate during bonding, such as bonding between an image sensor substrate and a logic device substrate. The film stack according to the present disclosure may be used to modulate stress and wafer warpage to improve bonding adhesion and device performance during various packaging schemes, such as CoWoS, SoIC, or the like. The film stack according to the present disclosure may be used to improve bonding process and device performance in both wafer-to-wafer bonding and die-to-die bonding.