Through Via Etch-Stop Structure for Reliable Lower Wiring Connection
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Solution Overview
Problem
The challenge in semiconductor devices is ensuring reliable connections between through vias and lower wiring layers, as excessive etching during the formation of lower wiring trenches can compromise the integrity of these connections.
Innovation Solution
Incorporating a sacrificial layer between the substrate and lower wiring layer, with a through via insulating layer acting as an etch stop, preventing excessive etching and enhancing the reliability of the connection between the through via and lower wiring layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lower wiring trench is etched deeply to expose the lower wiring layer, then the connection between through via and lower wiring layer can be established, but the etching may become excessive and compromise the integrity of the connection
Solution Approach 1:
The patent applies preliminary action by forming the through via insulating layer within the sacrificial layer before the lower wiring trench etching process. This pre-positioned insulating layer serves as a predetermined etch stop that will automatically halt the etching process at the correct depth, preventing over-etching and ensuring reliable connection between the through via and lower wiring layer.
Solution Approach 2:
The through via insulating layer acts as an intermediary element between the through via structure and the lower wiring layer. It provides a controlled interface that manages the etching process, ensuring that the lower wiring trench reaches the appropriate depth to establish reliable electrical connection without compromising structural integrity.
2Manufacturing precision
If the lower wiring trench is etched to the correct depth to maintain connection integrity, then the connection reliability is preserved, but the etching may be insufficient to fully expose the lower wiring layer
Solution Approach 1:
The patent replaces the mechanical control of etching depth (relying solely on process parameters and operator skill) with a material-based etch stop mechanism. The through via insulating layer provides a chemical/physical stopping point that automatically terminates the etching process, eliminating the need for precise mechanical depth control while ensuring both adequate exposure and connection integrity.
3Ease of manufacture
If no etch stop layer is used, then the manufacturing process is simpler, but the lower wiring trench may be excessively etched compromising connection integrity
Solution Approach 1:
The patent merges the through via insulating layer with the sacrificial layer, positioning the insulating layer within the sacrificial structure. This integration allows the etch stop function to be provided without adding a completely separate process step, maintaining relative process simplicity while ensuring connection integrity through the embedded insulating layer.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration improves the reliability of the connection between the through via and lower wiring layer by controlling the etching process, thereby maintaining structural integrity and performance.
Implementation Method 1
The through via insulating layer disposed inside the sacrificial layer may serve as an etch stop layer in a process of forming a lower wiring trench in which a lower wiring layer is formed
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes: a first substrate; an active pattern extending on the first substrate; a gate electrode extending on the active pattern; a source/drain region on the active pattern; a first interlayer insulating layer on the source/drain region; a sacrificial layer on the first substrate; a lower wiring layer on a lower surface of the sacrificial layer; a through via trench extending to the lower wiring layer by passing through the first interlayer insulating layer and the sacrificial layer in a vertical direction; a through via inside the through via trench and connected to the lower wiring layer; a recess inside the sacrificial layer and protruding from a sidewall of the through via trench in the second horizontal direction; and a through via insulating layer extending along the sidewall of the through via trench and into the recess.