Spin-on interlayer dielectric for non-planar transistors
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Solution Overview
Problem
In the fabrication of non-planar transistors, such as tri-gate and FinFETs, the formation of a void-free first level interlayer dielectric material layer that exerts tensile strain on source/drain regions is challenging, affecting transistor performance.
Innovation Solution
A spin-on coating technique followed by oxidation and annealing is used to form a void-free first level interlayer dielectric material layer, which exerts tensile strain on the source/drain regions, enhancing channel mobility and drive currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition techniques are used to form the interlayer dielectric layer, then the process is simple and fast, but voids form in high aspect ratio structures and tensile strain is not achieved
Solution Approach 1:
The patent changes the physical and chemical parameters of the dielectric material by using a spin-on-glass (SOG) material that can be oxidized. The oxidation process transforms the SOG into a denser material that exerts tensile strain on the source/drain regions. This parameter change enables both void-free gap fill in high aspect ratio structures and the desired tensile strain effect, resolving the contradiction between manufacturing precision and process complexity.
Solution Approach 2:
The patent utilizes a phase transition approach by oxidizing the spin-on-glass material. The oxidation process converts the as-deposited SOG phase into an oxidized phase with different properties - specifically, the oxidized material is denser and generates tensile strain. This phase transition enables the material to fill high aspect ratio gaps without voids while simultaneously providing the mechanical strain needed for enhanced carrier mobility.
2Productivity
If the interlayer dielectric material is densified to exert tensile strain, then drive current improves, but the deposition and processing becomes more complex
Solution Approach 1:
The spin-on-glass material is designed to be self-densifying through the oxidation process. Rather than requiring complex external densification equipment or multiple processing steps, the material automatically transforms into a denser state when exposed to oxidation conditions, thereby exerting tensile strain on the source/drain regions. This self-service mechanism improves drive current while avoiding the need for complex additional manufacturing steps.
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
The approach results in improved drive currents of up to 7% for NMOS tri-gate transistors by densifying the interlayer dielectric material and ensuring effective gap fill in high aspect ratio structures.
Implementation Method 1
A spin-on coating technique followed by oxidation and annealing is used to form a void-free first level interlayer dielectric material layer
Implementation Method 2
A spin-on coating technique followed by oxidation and annealing is used to form a void-free first level interlayer dielectric material layer
Implementation Method 3
A spin-on coating technique followed by oxidation and annealing is used to form a void-free first level interlayer dielectric material layer
Data Source
AI summary
The present description relates the formation of a first level interlayer dielectric material layer within a non-planar transistor, which may be formed by a spin-on coating technique followed by oxidation and annealing. The first level interlayer dielectric material layer may be substantially void free and may exert a tensile strain on the source/drain regions of the non-planar transistor.