Protective Layer Between Insulation and Wiring in Stacked Structures
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Solution Overview
Problem
The existing methods for manufacturing semiconductor units result in a reduction in reliability of connection terminal sections due to etching during isolation trench formation, which affects the connection between wirings in stacked structures.
Innovation Solution
A stacked structure and manufacturing method involving a protective layer of a different material from the insulating layer, where the wiring, insulating layer, and substrate are stacked, and the protective layer is positioned between the insulating layer and the wiring to prevent damage during etching, ensuring the reliability of connection terminal sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the oxide film is etched during formation of the isolation trench, then the isolation trench is successfully formed to separate stacked structures, but the wiring exposed in the isolation trench is concurrently etched, leading to reduction in reliability of the connection terminal section
Solution Approach 1:
A protective layer is introduced as an intermediary between the oxide film and the wiring. This protective layer is selectively etched away after the isolation trench is formed, allowing the wiring to be exposed only in the necessary regions while protecting it during the etching process. The protective layer acts as a temporary mediator that enables precise control over where the wiring is exposed.
Solution Approach 2:
The protective layer is formed on the wiring before the isolation trench etching process begins. This preliminary action ensures that the wiring is protected from etching damage during the isolation trench formation. The protective layer is then selectively removed after the trench is formed, achieving the desired exposure pattern without damaging the wiring.
2Ease of manufacture
If the through chip via formation technique is used to connect the first wiring to the second wiring, then the connection between wirings is established, but the substrate etching may cause the first wiring to be etched, leading to reduction in reliability of connection
Solution Approach 1:
The protective layer serves as an intermediary that protects the first wiring during the substrate etching process for through chip via formation. The protective layer is selectively removed only in the regions where connection is needed, allowing precise control over the etching process and preventing unwanted etching of the wiring while enabling reliable connections.
Solution Approach 2:
The protective layer is selectively removed in specific local regions where wiring exposure is required for connection. This local quality approach ensures that the wiring is protected in regions where it should remain intact while being exposed only where connection is needed, thereby maintaining connection reliability without unnecessary etching damage.
Data Source
AI summary
A stacked structure, includes: a wiring; an insulating layer; a substrate; and a protective layer, wherein the wiring, the insulating layer, and the substrate are stacked from a bottom side, and an end portion of the wiring is projected from a side face of the stacked structure, and the protective layer is provided between the insulating layer and at least a part of the wiring and is configured of a material different from a material configuring the insulating layer.