Via Network Structures for Bond Pad Mechanical Support
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Solution Overview
Problem
Integrated circuits face mechanical damage during manufacturing and packaging due to poor adhesion of bond-pads with underlying inter-metal dielectrics, leading to reliability issues such as metal peeling and bonding loss, which is particularly troublesome with Cu-based wire bonding.
Innovation Solution
The implementation of a via network structure with parallel via strips extending in different directions, supported by insulating material, to provide structural support to bond pads and enhance adhesion with metal layers, thereby mitigating mechanical damage and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional pads are added to reduce interaction between probing and bonding damages, then reliability is improved, but device complexity increases
Solution Approach 1:
The bond pad structure is segmented into multiple functional layers: the original bond pad, an underlying inter-metal dielectric layer, and a newly added via network layer with interconnected via strips. This segmentation allows each layer to perform its specific function while collectively improving reliability without requiring additional pads on the surface.
Solution Approach 2:
The via network layer is nested within the existing inter-metal dielectric layer beneath the bond pad. The via strips are embedded in the dielectric material, creating a nested structure that provides structural support without increasing the overall device footprint or requiring additional external pads.
2Strength
If pad material that is stronger and/or harder is used, then bond pad strength is improved, but manufacturing difficulty increases due to brittleness of inter-metal dielectrics
Solution Approach 1:
The via network of interconnected via strips is formed beforehand in the inter-metal dielectric layer to provide structural cushioning and support to the bond pad. This pre-formed network prevents cracks from propagating through the brittle dielectric material during subsequent manufacturing steps such as probing, wire-bonding, or metal bumping.
Solution Approach 2:
The solution creates a composite structure combining the brittle inter-metal dielectric material with a reinforced via network. This composite approach allows the use of standard dielectric materials while the embedded via network provides the necessary mechanical strength and crack resistance, avoiding the need to switch to stronger but more difficult-to-manufacture pad materials.
3Strength
If via network layers are added to support bond pad contacts, then structural support is improved, but device complexity increases
Solution Approach 1:
The via network layer serves multiple functions simultaneously: it provides structural support to the bond pad contacts, acts as an electrical connection pathway to underlying metal layers, and functions as a crack-arresting reinforcement structure within the inter-metal dielectric. This multi-functionality reduces the need for separate structural support elements.
Solution Approach 2:
The via network is merged with the existing inter-metal dielectric layer formation process. The via strips are patterned and formed within the same manufacturing sequence as the dielectric layers, combining the structural support function with the existing interconnect architecture rather than adding completely separate support structures.
Data Source
AI summary
A circuit device is configured with robust circuit connectors. In connection with various example embodiments, an integrated circuit device includes one or more via network layers below a bond pad contact, connecting the bond pad contact with one or more underlying metal layers. Each via network layer includes a plurality of via strips extending about parallel to the bond pad contact and in different directions to structurally support the bond pad contact.