Alignment Mark Bonding Using Dummy Marks for 3D IC Packaging
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Solution Overview
Problem
In the formation of three-dimensional integrated circuits, the bonding process often faces challenges with alignment marks, leading to suboptimal bonding strength and reliability due to the use of dielectric layers, which can result in non-bonding issues and reduced hybrid bonding quality.
Innovation Solution
The solution involves forming and bonding alignment marks to dummy alignment marks instead of dielectric layers, using metal-to-metal bonding to improve bonding strength and reliability, where dummy alignment marks do not serve a functional alignment purpose but participate in the bonding process, enhancing the hybrid bonding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alignment marks are bonded to dielectric layers, then the bonding process can be performed, but the bonding strength and reliability are reduced due to non-bonding issues
Solution Approach 1:
The patent changes the bonding target from dielectric layers to metal alignment marks, fundamentally altering the bonding interface parameters. This transition from dielectric-to-dielectric bonding to metal-to-metal bonding improves both bonding strength and reliability by eliminating non-bonding issues inherent in dielectric layer bonding
Solution Approach 2:
The patent introduces dummy alignment marks as intermediary elements that facilitate bonding. These dummy marks serve as bonding targets without interfering with the actual alignment process, enabling reliable metal-to-metal bonding while maintaining alignment functionality
2Strength
If alignment marks are used for bonding, then bonding strength is improved, but the alignment function may be compromised
Solution Approach 1:
The patent segments the alignment mark system into two distinct components: real alignment marks that perform the alignment function and dummy alignment marks that serve as bonding targets. This segmentation allows each component to optimize its specific function without compromising the other
Solution Approach 2:
Dummy alignment marks act as intermediaries that enable bonding without interfering with the alignment process. The real alignment marks maintain measurement precision for alignment, while the dummy marks provide suitable bonding targets, thus resolving the conflict between bonding strength and alignment precision
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 improves the bonding strength and reliability by avoiding non-bonding issues and enhancing the hybrid bonding quality, resulting in a more stable and efficient stacking of package components in three-dimensional integrated circuits.
Implementation Method 1
alignment marks may be formed for the bonding apparatus to align the stacked wafers/dies
Implementation Method 2
bonding alignment marks to dummy alignment marks instead of dielectric layers, using metal-to-metal bonding to improve bonding strength and reliability
Data Source
AI summary
A method includes placing a first package component. The first package component includes a first alignment mark and a first dummy alignment mark. A second package component is aligned to the first package component. The second package component includes a second alignment mark and a second dummy alignment mark. The aligning is performed using the first alignment mark for positioning the first package component, and using the second alignment mark for position the second package component. The second package component is bonded to the first package component to form a package, with the first alignment mark being bonded to the second dummy alignment mark.