Semiconductor Seal Ring Buffer Zone Design
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Solution Overview
Problem
The semiconductor industry faces challenges in miniaturization, higher speed, and lower power consumption due to limitations in packaging techniques, particularly in preventing damage to internal circuit regions during die processing and reducing manufacturing defects like delamination.
Innovation Solution
A semiconductor device package design featuring a seal ring that encircles the functional circuit region with a buffer zone to absorb stress and mitigate damage, combined with passivation and polymer layers that extend laterally into the buffer zone to act as a landing pad for polymer layers, reducing stress and manufacturing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal ring is formed closer to the functional circuit region to improve sealing effectiveness, then the sealing performance is improved, but the risk of damage to the internal circuit region increases
Solution Approach 1:
The seal ring structure is divided into two portions: a first portion formed within the interconnect structure and a second portion formed over the passivation layer. This segmentation allows the seal ring to extend vertically without laterally encroaching on the functional circuit region, thus maintaining sealing effectiveness while avoiding damage to internal circuits.
Solution Approach 2:
The seal ring transitions from a purely lateral arrangement to a vertical arrangement by extending upward through the passivation layer. This dimensional change allows the seal ring to achieve better sealing contact in the vertical dimension while maintaining safe lateral distance from the functional circuit region.
2Reliability
If the polymer layer is formed to cover the entire die surface to improve protection, then the protective coverage is improved, but the stress-induced delamination increases
Solution Approach 1:
The second portion of the seal ring acts as an intermediary stress-absorbing element between the polymer layer and the functional circuit region. It provides a compliant interface that accommodates stress from the polymer layer without transmitting it to the sensitive interconnect structure, preventing delamination while maintaining protective coverage.
Solution Approach 2:
The seal ring's second portion extending into the buffer zone is positioned beforehand to absorb and mitigate stress before it can reach the functional circuit region. This pre-positioned cushioning structure prevents stress-induced delamination by dissipating mechanical stress in a controlled manner.
3Productivity
If the minimum feature size is reduced to increase integration density, then the integration density is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The seal ring structure utilizes the vertical dimension by extending through the passivation layer, allowing effective sealing without requiring tight lateral dimensional control. This reduces the manufacturing precision burden on lateral feature sizes while maintaining sealing effectiveness.
Solution Approach 2:
Dividing the seal ring into two portions formed at different stages allows independent optimization of each portion's dimensions and formation conditions, reducing the cumulative precision requirements compared to forming a single integrated seal ring structure.
Data Source
AI summary
An embodiment device includes a semiconductor substrate and an interconnect structure over the semiconductor substrate. The interconnect structure includes a functional circuit region and a first portion of a seal ring spaced apart from the functional circuit region by a buffer zone. The device also includes a passivation layer over the interconnect structure and a second portion of the seal ring over the passivation layer and connected the first portion of the seal ring. The second portion of the seal ring is disposed in the buffer zone.