Redundant Bonded Interconnect Circuitry for Void-Tolerant Stacks
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Solution Overview
Problem
In stacked semiconductor elements, voids and debris at the bond interface can inhibit reliable electrical connections between contact pads, leading to faulty interconnects and reduced device yield.
Innovation Solution
The implementation of redundant electrical connections and switching circuitry allows for rerouting of electrical signals around failed connections, ensuring continuous connectivity between stacked semiconductor elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If direct bonding of contact pads is used to achieve high-density interconnects, then device integration density is improved, but reliability deteriorates due to voids and debris at the bond interface
Solution Approach 1:
The patent divides the bonding interface into multiple discrete bonding regions, each with its own redundant contact pads. This segmentation allows isolated voids or debris to affect only specific bonding regions while other regions maintain reliable connections, thus preserving overall connection reliability while achieving high interconnect density.
Solution Approach 2:
The patent incorporates redundant contact pads during the initial bonding process rather than adding them later. These redundant pads are pre-positioned and electrically connected through trace circuitry, enabling automatic rerouting if primary connections fail, thereby maintaining reliability without requiring post-bonding repairs.
2Reliability
If redundant contact pads are added to improve reliability, then connection reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the redundant contact pads with the primary contact pads into a unified bonding interface structure. Both primary and redundant pads share the same bonding layer and are interconnected through trace circuitry, creating an integrated system that provides redundancy without adding separate structural components or increasing overall device complexity.
Solution Approach 2:
The patent introduces trace circuitry as an intermediary element that electrically connects primary contact pads to redundant contact pads. This intermediary routing layer enables automatic signal rerouting when primary connections fail, providing reliability enhancement through a simple conductive path rather than complex switching logic or control circuitry.
3Reliability
If bonding area is increased to improve connection reliability, then reliability is improved, but manufacturing precision requirements worsen due to larger bonding interfaces
Solution Approach 1:
The patent applies local quality by concentrating bonding reliability enhancement at specific critical locations rather than uniformly increasing the entire bonding interface area. Redundant contact pads are strategically positioned at locations most susceptible to void formation or alignment errors, providing targeted reliability improvement without requiring proportional increases in overall bonding precision across the entire interface.
Data Source
AI summary
A bonded structure is disclosed. The bonded structure can include a first element that has a first plurality of contact pads. The first plurality of contact pads includes a first contact pad and a second redundant contact pad. The bonded structure can also include a second element directly bonded to the first element without an intervening adhesive. The second element has a second plurality of contact pads. The second plurality of contact pads includes a third contact pad and a fourth redundant contact pad. The first contact pad is configured to connect to the third contact pad. The second contact pad is configured to connect to the fourth contact pad. The bonded structure can include circuitry that has a first state in which an electrical signal is transferred to the first contact pad and a second state in which the electrical signal is transferred to the second contact pad.