Multi-stacked TSV Device with Insulating Spacers
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Solution Overview
Problem
Forming a stable through-silicon via (TSV) structure that passes through multiple semiconductor substrates and insulating layers is challenging due to the requirement for advanced photolithography and etching technologies, especially for devices with tens of micrometers to hundreds of micrometers in thickness.
Innovation Solution
A multi-stacked device configuration with TSV structures that include insulating spacers between substrates and layers, allowing the TSV structure to pass through multiple substrates and layers while being electrically connected, and using TSV pads and bumps for inter-device connection, with spacers ensuring electrical insulation and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a TSV structure passes through multiple semiconductor substrates and insulating layers, then electrical connection reliability is improved, but manufacturing complexity increases due to requiring advanced photolithography and etching technologies
Solution Approach 1:
The patent divides the continuous TSV structure into multiple segments by introducing insulating spacers at different levels. The TSV structure is segmented into first TSV structures in the lower device, second TSV structures in the intermediate device, and third TSV structures in the upper device, with insulating spacers between them. This segmentation allows each segment to be formed with less stringent process requirements while maintaining overall electrical connectivity through conductive portions.
Solution Approach 2:
The patent introduces insulating spacers as intermediary elements between the TSV structures and semiconductor substrates. These spacers act as mediators that provide electrical insulation while allowing the TSV structures to maintain mechanical and electrical connection pathways. The spacers are positioned at specific locations where substrates are thinned or removed, enabling controlled electrical isolation without compromising the overall TSV functionality.
2Reliability
If additional insulating layers are added in the TSV hole, then electrical insulation is improved, but contact resistance increases and hole-open failures may occur
Solution Approach 1:
The patent applies insulating spacers selectively at specific locations rather than uniformly throughout the TSV structure. The spacers are positioned where substrates are thinned or removed, providing local electrical insulation exactly where needed. This localized approach maintains low contact resistance in critical connection areas while providing sufficient insulation where substrates are absent or thinned.
Solution Approach 2:
The patent uses partial insulating action by introducing spacers only at specific segments of the TSV structure rather than completely filling the TSV hole with insulating material. This partial application of insulation provides sufficient electrical isolation to prevent leakage while maintaining low contact resistance in the conductive portions that require direct electrical connection.
Data Source
AI summary
A multi-stacked device includes a lower device having a lower substrate, a first insulating layer on the lower substrate, and a through-silicon-via (TSV) pad on the first insulating layer, an intermediate device having an intermediate substrate, a second insulating layer on the intermediate substrate, and a first TSV bump on the second insulating layer, an upper device having an upper substrate, a third insulating layer on the upper substrate, a second TSV bump on the third insulating layer, and a TSV structure passing through the upper substrate, the third insulating layer, the second insulating layer, and the intermediate substrate to be connected to the first TSV bump, the second TSV bump, and the TSV pad. An insulating first TSV spacer between the intermediate substrate and the TSV structure and an insulating second TSV spacer between the upper substrate and the TSV structure are spaced apart along a stacking direction.