Bond Pad Structure with Segmented Conductive Layers
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Solution Overview
Problem
Conventional bond pad structures in integrated circuits face mechanical stress from interconnection and electrical testing procedures, leading to potential damage such as cracking and delayering, especially as underlying layers become more fragile with advancing semiconductor technology.
Innovation Solution
A bond pad structure featuring a circuit under pad (CUP) design with a lower conductive layer, an intermediate conductive layer that interposes between the lower and upper conductive layers, and passivation layers, which provides improved stress distribution and electrical connectivity, using materials like copper and dielectric layers with low dielectric constants to reduce parasitic capacitance and enhance mechanical resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bond pad structures are used with interconnection techniques, then electrical connection is achieved, but mechanical stress causes damage such as cracking and delayering
Solution Approach 1:
The bond pad structure is divided into multiple conductive layers (first conductive layer, second conductive layer, third conductive layer) separated by dielectric layers. This segmentation distributes mechanical stress across multiple interfaces rather than concentrating it at a single bond pad interface, reducing the risk of cracking and delayering while maintaining electrical connectivity.
Solution Approach 2:
Dielectric layers are introduced as intermediary materials between the conductive layers. These dielectric layers act as stress-absorbing intermediaries that cushion mechanical stress from bonding and testing procedures, preventing direct transmission of stress to the underlying substrate and protecting the bond pad structure from damage.
2Reliability
If conventional bond pad structures are used, then electrical connection is provided, but parasitic capacitance increases and electrical performance deteriorates
Solution Approach 1:
The structure modifies electrical parameters by introducing multiple dielectric layers with different dielectric constants between conductive layers. This changes the capacitance distribution and reduces overall parasitic capacitance compared to conventional single-layer structures, thereby improving electrical performance and reducing energy loss.
3Reliability
If layers with low dielectric constant are used to reduce parasitic capacitance, then electrical performance improves, but mechanical fragility increases
Solution Approach 1:
The patent employs composite material structure with multiple dielectric layers (first dielectric layer, second dielectric layer) having different properties. By combining dielectric materials with different mechanical and electrical characteristics, the structure achieves both low parasitic capacitance (through low-k materials) and adequate mechanical strength (through supportive dielectric layers), resolving the contradiction between electrical performance and mechanical fragility.
Data Source
AI summary
A bonding pad structure is provided that includes two conductive layers and a connective layer interposing the two conductive layers. The connective layer includes a contiguous, conductive structure. In an embodiment, the contiguous conductive structure is a solid layer of conductive material. In other embodiments, the contiguous conductive structure is a conductive network including, for example, a matrix configuration or a plurality of conductive stripes. At least one dielectric spacer may interpose the conductive network. Conductive plugs may interconnect a bond pad and one of the conductive layers.