Semiconductor Die Side Bonding for Compact Stacking
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Solution Overview
Problem
Existing semiconductor bonded assemblies face challenges in providing reliable electrical connections across multiple dies without lateral expansion, requiring reduction in die size and reliance on exposed top surface bonding pads.
Innovation Solution
The method involves forming external bonding pads within semiconductor dies, using sacrificial pad cover structures to create side cavities, and injecting bonding wire material to form connection wires that extend over sidewalls, enabling electrical connections without increasing the assembly's lateral size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external bonding pads are physically exposed on top surfaces for wire attachment, then electrical connections can be established, but the assembly requires larger lateral size or reduced die size
Solution Approach 1:
The bonding pads are moved from the top surface (2D plane) to the sidewall (vertical dimension), allowing wire bonding to occur from the side rather than from above. This dimensional shift enables compact vertical stacking without requiring lateral expansion of the assembly footprint.
Solution Approach 2:
The bonding pads are embedded within recesses formed in the sidewalls of the semiconductor dies. This nesting approach allows the bonding pads to be integrated into the die structure itself, eliminating the need for additional lateral space while maintaining reliable electrical connections.
2Area of stationary object
If die size is reduced to limit lateral expansion, then assembly size is controlled, but manufacturing complexity and connection reliability increase
Solution Approach 1:
By transitioning from top-surface bonding to sidewall bonding, the invention eliminates the need to reduce die dimensions. The vertical utilization of sidewall space allows standard-sized dies to be used in compact assemblies, avoiding the manufacturing challenges associated with miniaturization.
3Reliability
If through-silicon vias are used to create lateral connections, then electrical connections are achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The invention extracts the bonding pad functionality from the traditional top-surface location and relocates it to the sidewall. This extraction eliminates the need for through-silicon via fabrication, which involves complex steps including drilling, plating, and filling, thereby simplifying the manufacturing process while maintaining connection reliability.
Data Source
AI summary
A bonded assembly includes a first stack containing a first semiconductor die bonded to a second semiconductor die along a stacking direction, first external bonding pads formed within the first semiconductor die, and bonding connection wires. Each of the bonding connection wires extends over a sidewall of the first semiconductor die and protrudes into the first semiconductor die through the sidewall of the first semiconductor die to contact a respective one of the first external bonding pads.