Fin Memory Work Function Layout for Signal Interference Control
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Solution Overview
Problem
The instability of memory due to increased electronic signal interference between adjacent storage capacitors, caused by reduced process nodes and smaller dimensions of shallow trench isolating structures, leads to reduced maintenance time of electrons in storage capacitors.
Innovation Solution
Adjusting the thickness of work function layers on the side walls of memory fins to create a greater threshold voltage difference between areas where first fins face each other and areas where they face second fins, reducing electron diffusion and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If process nodes are reduced and dimensions of shallow trench isolating structures are reduced, then memory density is improved, but electronic signal interference between adjacent storage capacitors increases
Solution Approach 1:
The patent applies local quality by creating different work function layer thicknesses at different locations: thicker work function layers (first thickness) are formed on side walls where first fins face each other, while thinner work function layers (second thickness) are formed on side walls where first fins face second fins. This local differentiation addresses the electron diffusion problem specifically in regions where first fins are in close proximity, thereby reducing signal interference while maintaining high memory density.
Solution Approach 2:
The patent changes the work function layer thickness parameter to control electron diffusion. By adjusting the thickness of work function layers based on the specific fin configuration (first thickness for first fin-to-first fin interfaces, second thickness for first fin-to-second fin interfaces), the patent creates different threshold voltages that prevent electron diffusion between adjacent first fins while maintaining overall memory cell functionality.
2Quantity of substance
If spacing between adjacent first fins is reduced, then memory cell density is improved, but electron diffusion between first fins increases
Solution Approach 1:
The patent implements local quality by applying thicker work function layers specifically at the side walls of first fins that face other first fins, while using thinner work function layers at side walls facing second fins. This localized approach directly addresses electron diffusion in the critical first fin-to-first fin regions while maintaining acceptable threshold voltage characteristics elsewhere, thus preserving electron stability in storage capacitors despite reduced spacing.
Solution Approach 2:
The work function layer acts as an intermediary element between adjacent first fins. By positioning the work function layer on the side walls of first fins and controlling its thickness, it serves as a barrier that mediates electron diffusion between closely spaced first fins, enabling reduced spacing while maintaining electron stability.
3Stability of the object's composition
If threshold voltage difference between fin areas is increased, then electron diffusion is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent resolves the manufacturing complexity issue by implementing local quality through a targeted approach: thicker work function layers are applied only where first fins face each other (requiring higher threshold voltage to prevent electron diffusion), while thinner work function layers are used where first fins face second fins. This selective differentiation achieves the necessary threshold voltage variation without requiring complex manufacturing processes across the entire structure.
Data Source
AI summary
The embodiments of the present disclosure provide a memory and a manufacturing method of a memory. The memory includes first fins and second fins disposed on a substrate, a dielectric layer covering tops of the first fins and side wall surfaces exposed by an isolating structure, and work function layers disposed on a surface of the dielectric layer. In a direction parallel to an arrangement direction of the first fins and the second fins, the work function layers on the side walls where the adjacent first fins are opposite are provided with a first thickness, and the work function layers on the side walls where the first fins face towards the second fins are provided with a second thickness. The first thickness is greater than the second thickness.