Interconnect Diffusion Barrier for Misaligned Die Bonding
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Solution Overview
Problem
Misalignment of conductive interconnect structures during the bonding of stacked dies or wafers leads to conductive material diffusion into dielectric, causing performance degradation, leakage, and shorting issues, which adversely affect package yield and performance.
Innovation Solution
Implementing a barrier interface composed of materials with lower diffusivity than the dielectric, such as silicon nitride or air gaps, around the conductive interconnect pads to inhibit diffusion and prevent misalignment-induced contact with the dielectric.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If misalignment of conductive interconnect structures occurs during bonding, then placement flexibility is improved, but conductive material diffusion into dielectric causes performance degradation
Solution Approach 1:
A barrier layer is introduced as an intermediary between the conductive interconnect structure and the dielectric material. This barrier layer prevents direct contact and diffusion of conductive material into the dielectric, even when misalignment occurs during bonding, thereby maintaining reliability while allowing placement flexibility
Solution Approach 2:
The barrier layer is formed in advance around the conductive interconnect structure before bonding occurs. This preliminary protective action prevents the harmful diffusion effect from occurring in the first place, allowing misalignment without compromising performance
2Reliability
If barrier interface is implemented to prevent diffusion, then reliability is improved, but device complexity increases
Solution Approach 1:
The barrier layer is applied locally only around the conductive interconnect structures where diffusion prevention is needed, rather than uniformly across the entire die surface. This localized approach maintains reliability while minimizing additional device complexity
Solution Approach 2:
The barrier layer uses materials with specific properties (lower diffusivity than the dielectric) to achieve diffusion prevention. By selecting appropriate composite material combinations, the patent achieves reliable protection without excessive structural complexity
3Reliability
If strict alignment precision is required to prevent diffusion, then performance is maintained, but manufacturing precision requirements increase
Solution Approach 1:
The barrier layer serves as a mediator that decouples the relationship between alignment precision and performance. By providing a protective interface, it allows greater placement tolerance while maintaining performance, thereby reducing manufacturing precision requirements
Solution Approach 2:
The barrier layer provides a cushioning effect against misalignment by preventing diffusion even when offset occurs. This beforehand protection allows the manufacturing process to operate with lower precision requirements without compromising final performance
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
The barrier interface effectively reduces or prevents conductive material diffusion into the dielectric, enhancing package reliability and performance by maintaining electrical integrity and improving throughput by relaxing placement accuracy requirements.
Implementation Method 1
the barrier interface effectively reduces or prevents conductive material diffusion into the dielectric
Data Source
AI summary
Representative implementations of techniques and devices are used to reduce or prevent conductive material diffusion into insulating or dielectric material of bonded substrates. Misaligned conductive structures can come into direct contact with a dielectric portion of the substrates due to overlap, especially while employing direct bonding techniques. A barrier interface that can inhibit the diffusion is disposed generally between the conductive material and the dielectric at the overlap.