Through-Substrate Contact Plug With Insulating Film
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving higher integration and flexibility in design due to the risk of short circuits between contact electrodes and gate electrodes, particularly when contact electrodes are formed on the back-surface side of the substrate, and these designs are not applicable to typical bulk semiconductor transistors.
Innovation Solution
A semiconductor device structure featuring a contact plug that extends from the front surface to the back surface of the substrate, covered by an insulating film, which prevents unintentional short circuits and allows for higher integration and flexibility in design, suitable for both bulk and silicon-on-insulator (SOI) structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the contact electrode is disposed on the back-surface side of the substrate, then flexibility in wiring paths is improved, but the risk of short circuit with gate electrode increases
Solution Approach 1:
An insulator layer is introduced as an intermediary between the contact electrode and the gate electrode. This insulator layer extends from the front surface to the back surface of the substrate, electrically isolating the contact electrode from the gate electrode and preventing short circuits while maintaining the back-surface contact configuration for wiring flexibility.
Solution Approach 2:
The contact electrode is extended into the thickness direction of the substrate, passing through from the back surface to the front surface. This three-dimensional configuration allows the contact electrode to connect to the source-drain region while being isolated by the insulator layer, resolving the short circuit risk associated with back-surface contact.
2Quantity of substance
If higher integration is attempted with back-surface contact electrode, then device density is improved, but alignment precision requirements increase causing short circuit risk
Solution Approach 1:
The insulator layer serves as a robust intermediary that provides electrical isolation regardless of alignment variations. This allows for higher device density with relaxed alignment precision requirements, as the insulator layer prevents short circuits even when manufacturing tolerances cause positional variations.
3Adaptability or versatility
If contact electrode passes through substrate and diffusion layer, then wiring flexibility is improved, but complexity of structure increases
Solution Approach 1:
The insulator layer performs multiple functions: it provides electrical isolation between the contact electrode and gate electrode, serves as a structural support for the contact electrode passing through the substrate, and enables back-surface contact configuration. This multi-functionality reduces overall device complexity despite the through-substrate contact path.
Data Source
AI summary
A semiconductor device including a semiconductor substrate with a first surface and a second surface facing each other, the semiconductor substrate having an element region in which a transistor is provided on the first surface, and a separation region in which an element separating layer surrounding the element region is provided; a contact plug extending from the first surface to the second surface, in the element region of the semiconductor substrate; and an insulating film covering a periphery of the contact plug.