Bonded Die Corner Offset Layout for Crack Reduction
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Solution Overview
Problem
The fabrication processes for bonded die structures often result in stress-induced cracking and defects due to differences in thermal expansion coefficients between materials, particularly at the corner regions of the dies, which can lead to reduced device performance and yields.
Innovation Solution
The bonded die structures are designed with a second die bonded to a first die, where the corner regions of the second die are configured to have a smaller length dimension than the adjacent corner regions of the first die, and an offset distance is maintained to minimize stress concentration, thereby redistributing stress away from the first die's corners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional bonding processes are used to bond second die to first die, then integration density is improved, but stress-induced cracking occurs at corner regions due to thermal expansion coefficient differences
Solution Approach 1:
The patent applies asymmetry by making the corner regions of the second die smaller than the corner regions of the first die. This asymmetric configuration ensures that the second die does not fully extend beyond the first die at the corners, creating an offset distance that reduces stress concentration and prevents cracking while maintaining high integration density through bonded die structures.
2Area of stationary object
If dies are bonded in three-dimensional stacked configuration, then area occupancy is reduced, but stress concentration at corner regions increases leading to device failure
Solution Approach 1:
The patent applies local quality by differentiating the corner region dimensions of the second die from its main body and from the first die. Specifically, the corner regions of the second die are made smaller to create an offset configuration at critical stress points, while the central bonding area maintains full contact for electrical connectivity. This localized modification strengthens stress resistance at corner regions without compromising the three-dimensional stacked configuration's area efficiency.
3Area of stationary object
If corner regions of second die extend beyond first die, then bonding area is maximized, but stress concentration at first die corners increases causing cracks
Solution Approach 1:
The patent applies segmentation by dividing the second die into distinct regions: a central bonding area that contacts the first die for electrical connectivity, and smaller corner regions that do not extend beyond the first die. This segmentation separates the bonding function from the corner regions, allowing maximum bonding area in the central region while preventing stress concentration at the corners through the offset configuration.
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 configuration reduces the occurrence of crack defects in the first die, improving device performance and yield by minimizing stress concentrations and promoting better stress distribution.
Implementation Method 1
an offset distance between the corner side of the second die and the corner side of the first die is less than or equal to at least one of a first offset distance between a first side of the second die and a first side of the first die and a second offset distance between a second side of the second die and a second side of the first die, thereby reducing the occurrence of crack defects in the first die
Data Source
AI summary
Bonded die structures and methods of fabricating bonded die structures with improved stress distribution. A bonded die structure may include a second die bonded to a first die. The sizes, shapes and/or relative position of the first die with respect to the second die may be configured to minimize stress concentrations in the bonded die structure. In some embodiments, a length dimension of a corner region of the second die may be less than a length dimension of the adjacent corner region of the first die, which may aid in redistributing stress away from the corner of the first die. An offset distance between the corner of the second die and the corner of the first die may also be controlled to minimize stress applied to the corner of the first die along a vertical direction. Accordingly, crack formation may be reduced, and device performance and yields may be improved.