3D Semiconductor Die Structure with Peg and Containing Feature Alignment
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Solution Overview
Problem
Die movement during pick and place and thermal compression bonding in semiconductor manufacturing leads to shorting or misalignment of interconnects, especially when using large pads and organic adhesives, which are not effectively managed by existing methods.
Innovation Solution
The use of asymmetrically sized electroplated pegs and pads on dies and wafers, with interlaced Cu peg and pad structures acting as stops to prevent die shifting, allowing for improved alignment and bonding through the use of temporary adhesives and thermal compression bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If large pads are used for die to die interconnections to account for placement misalignment, then alignment tolerance is improved, but metal bonding material can run on the die surface causing shorting of adjacent interconnects
Solution Approach 1:
The bonding pad structure is segmented into multiple functional zones: a larger outer pad region for alignment tolerance and a smaller inner bonding area for controlled material confinement. This segmentation allows the pad to simultaneously provide misalignment tolerance while preventing metal bonding material from spreading to adjacent interconnects.
Solution Approach 2:
Different regions of the bonding pad are given different properties - the central bonding area has controlled dimensions to confine metal material, while the surrounding outer region provides alignment tolerance. This local differentiation resolves the contradiction between needing large pads for alignment and small pads to prevent shorting.
2Strength
If thermal compression bonding is used for die to wafer bonding, then bonding strength is improved, but die movement during the process causes connect to connect shorting or misaligned opens
Solution Approach 1:
Die attachment features (such as protrusions or alignment marks) are formed on the die before the thermal compression bonding process. These pre-formed features guide die placement and constrain movement during bonding, ensuring alignment precision is maintained throughout the high-strength bonding process.
3Manufacturing precision
If asymmetrically sized electroplated pegs and pads are used with interlaced Cu structures, then die shifting is prevented, but manufacturing process complexity increases
Solution Approach 1:
Asymmetrically sized electroplated pegs and pads are used where the peg dimensions are deliberately smaller than the corresponding pad dimensions. This asymmetric design creates a mechanical constraint that prevents die shifting during bonding while maintaining manufacturing feasibility through standard electroplating processes.
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 solution ensures robust die-to-wafer alignment and prevents undesirable shifting during bonding, enhancing the reliability and precision of semiconductor die connections.
Implementation Method 1
asymmetrically sized electroplated pegs and pads on dies and wafers
Implementation Method 2
interlaced Cu peg and pad structures acting as stops to prevent die shifting
Data Source
AI summary
A die-on-die assembly has a first die (10) and a second die (50). The first die (10) has a first contact extension (28,42) and a peg (32,44,45) extending a first height above the first die. The second die (50) has a second contact extension (68) connected to the first contact extension and has a containing feature (62) extending a second height above the second die surrounding the peg. The peg extends past the containing feature. Because the peg extends past the containing feature, lateral movement between the first and second die can cause the peg to come in contact with and be constrained by the containing feature. The peg and containing feature are thus useful in constraining movement between the first and second die.