TSV Backside Pad Dam Structure for Crack-Resistant Chip Stacking
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Solution Overview
Problem
Semiconductor packages with through-silicon vias (TSVs) face challenges in maintaining reliability due to cracking propagation, which can lead to electrical failures, especially when stacked in vertical configurations.
Innovation Solution
Incorporating a dam structure around the through-via in the semiconductor package, which is spaced apart from the via and has a specific height and width ratio, to prevent cracking propagation and enhance reliability without increasing package thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dam structure is added around the through-via to prevent cracking propagation, then reliability is improved, but device complexity increases
Solution Approach 1:
The backside pad is segmented into multiple functional regions: an electrode pad portion for electrical connection and a dam structure for crack prevention. This segmentation allows the single backside pad to simultaneously perform electrical connection and mechanical protection functions, resolving the contradiction between improved reliability and increased device complexity.
Solution Approach 2:
The backside pad is designed to serve multiple functions: it provides electrical connection through the electrode pad portion and prevents cracking propagation through the integrated dam structure. This multi-functionality eliminates the need for separate protective structures, thereby improving reliability without significantly increasing device complexity.
2Reliability
If the dam structure is positioned close to the through-via to effectively block cracks, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The dam structure is positioned at a specific location within the backside pad at a distance of about 1 μm to about 5 μm from the through-via, creating a localized protective barrier. This localized positioning provides effective crack prevention while maintaining reasonable manufacturing precision requirements, as the dam structure is placed where it is most needed without requiring extreme precision across the entire device.
3Reliability
If the backside pad width is increased to provide a larger dam structure, then reliability is improved, but the package area increases
Solution Approach 1:
The width ratio of the backside pad to the through-via is optimized to be within a range of about 5:1 to about 3:1. This parameter optimization ensures the dam structure is sufficiently large to prevent crack propagation while minimizing the increase in package area, thereby resolving the contradiction between improved reliability and increased area.
Data Source
AI summary
A semiconductor package includes a plurality of semiconductor chips. At least one of the semiconductor chips includes a semiconductor substrate including a semiconductor layer and a passivation layer having a third surface, a backside pad on the third surface, and a through-via penetrating through the semiconductor substrate. The backside pad includes an electrode pad portion, on the third surface, and a dam structure protruding on one side of the electrode pad portion and surrounding a side surface of the through-via. The dam structure is spaced apart from the side surface of the through-via.