Metal Bonding Pillars for Image Sensor Substrate Joining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The bonding quality in image sensor devices, particularly in CMOS image sensors using TSV process technology, is compromised due to stress exerted during processing, and organic bonding materials can lead to outgassing issues during high-temperature CVD, affecting film deposition and layer peeling.
Innovation Solution
The use of metal connection pillars and pads, such as copper or aluminum and germanium, for bonding between substrates, which provides better mechanical support, uniformity, and resistance to high temperatures, eliminating outgassing and improving bond line thickness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If organic bonding materials are used for bonding substrates, then bonding flexibility is improved, but outgassing occurs during high-temperature CVD processing causing film deposition defects and layer peeling
Solution Approach 1:
The patent changes the material parameter from organic bonding material to metal bonding material (such as copper or aluminum). This parameter change eliminates the outgassing issue during high-temperature CVD processing while maintaining bonding flexibility, as metals do not undergo the same thermal decomposition and gas release as organic materials.
Solution Approach 2:
The patent employs metal materials (copper or aluminum) as bonding materials between substrates. These metal materials provide both the necessary bonding flexibility and resistance to high-temperature processing, eliminating the harmful outgassing effect that plagues organic bonding materials during CVD operations.
2Reliability
If metal connection pillars and pads are used for bonding, then resistance to high temperatures and mechanical support are improved, but manufacturing complexity increases
Solution Approach 1:
The metal connection pillars and pads serve multiple functions simultaneously: they provide mechanical support between substrates, conduct electrical signals, and resist high-temperature processing. This multi-functionality justifies the additional manufacturing steps, as a single component structure accomplishes what would otherwise require multiple separate elements.
Solution Approach 2:
The patent applies metal bonding materials specifically at the connection regions (connection pillars and pads) where high temperature resistance and mechanical strength are most critical, rather than throughout the entire device. This localized application of enhanced material properties addresses the reliability needs at stress points while minimizing overall manufacturing complexity.
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 bonding quality by preventing layer peeling and ensuring robustness under backend processing temperatures, resulting in improved image sensor device performance and reliability.
Implementation Method 1
the connection pillars on the top substrate are bonded to the connection pads in the subassembly
Data Source
AI summary
An image sensor device includes a top substrate and a subassembly. The top substrate includes a plurality of connection pillars, and the subassembly includes a plurality of connection pads. The connection pillars on the top substrate are bonded to the connection pads in the subassembly. The connection pillars are formed of a first metal and the connection pads are formed of a second metal.