Stacked Semiconductor Device with Metal Bond Interconnects
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Solution Overview
Problem
Existing semiconductor devices face challenges in effectively stacking circuits with different functions while maintaining reliable electrical connections and insulation, particularly in image sensors where multiple circuit layers require efficient interconnections.
Innovation Solution
A semiconductor device architecture that includes multiple stacked substrates with conductive pads and intermediate connections, utilizing metal bonds and oxide layers for electrical connectivity, allowing for efficient interlayer connections between circuit layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple semiconductor substrates are stacked to integrate different circuit layers, then circuit integration and functionality are improved, but ensuring reliable electrical connections and insulation between layers becomes more difficult
Solution Approach 1:
The patent introduces an intermediate connection structure comprising a lower metal bond, upper metal bond, and filling metal that mediates between the second conductive pad and third conductive pad across the oxide layer interface. This intermediary structure ensures reliable electrical connection by providing continuous conductive paths through the insulating oxide layer, resolving the contradiction between layer integration and connection reliability.
Solution Approach 2:
The patent employs composite material structures including the combination of oxide layers (insulating) with metal bonds (conductive), and the integration of multiple substrate materials. This composite approach allows simultaneous achievement of electrical insulation between layers and reliable conductive paths through the metal components, addressing both insulation and connection reliability requirements.
2Reliability
If intermediate connections extend through oxide layers to connect conductive pads across substrates, then electrical connectivity between layers is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent forms the oxide layer on the second substrate before creating the intermediate connection. This preliminary action establishes the insulating barrier in advance, allowing subsequent metal bond formation and filling operations to proceed systematically. By preparing the oxide layer first, the manufacturing process manages complexity through staged construction rather than attempting to create the complete intermediate connection in a single complex step.
Solution Approach 2:
The intermediate connection is segmented into distinct components: lower metal bond, filling metal, and upper metal bond. This segmentation allows each component to be formed and optimized independently through separate manufacturing steps, reducing overall manufacturing complexity compared to creating a monolithic connection structure. Each segment serves a specific function and can be processed with appropriate techniques.
Data Source
AI summary
A semiconductor device includes a first semiconductor substrate having a first wiring layer which includes a first conductive pad, a second semiconductor substrate disposed on the first semiconductor substrate and including a second wiring layer which includes a second conductive pad, a first oxide layer disposed on the second semiconductor substrate and containing a second end of an intermediate connection which extends vertically through the second semiconductor substrate and has a first end electrically connected to the second conductive pad, and a third semiconductor substrate disposed on the first oxide layer and including a third wiring layer which includes a third conductive pad. The second end of the intermediate connection layer is electrically connected to the third conductive pad via a metal bond.