Flowable Oxide Deposition for Void-Free Gap Fill
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Solution Overview
Problem
Existing semiconductor deposition processes face challenges in filling high aspect ratio gaps with void-free dielectric material due to the formation of cusps and pinch-off issues, especially in narrow features, which exacerbates as device geometries shrink and thermal budgets are reduced.
Innovation Solution
The method involves rapid introduction of a silicon-containing precursor and an oxidant into a deposition chamber, allowing for a controlled reaction to form a flowable film that minimizes process sensitivities and achieves rapid target concentration ratios, using techniques like 'puffing' to introduce excess process gases and maintain precise control over delivery rates and temporal shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If HDP CVD is used for high aspect ratio gap-fill, then directional bottom-up deposition is achieved, but cusp formation and pinch-off occur at the entry region
Solution Approach 1:
The patent inverts the conventional HDP CVD approach by using a flowable CVD chemistry that deposits material in a liquid-like state which then flows to fill the gap uniformly, rather than relying on directional vapor deposition. This inversion of the deposition mechanism eliminates the cusp formation and pinch-off problems inherent in directional HDP CVD.
Solution Approach 2:
The patent changes the physical state parameter of the deposited material from vapor-phase solid deposition (HDP CVD) to liquid-phase flowable deposition. By controlling temperature and pressure parameters, the material is deposited as a flowable liquid that can uniformly fill high aspect ratio gaps without forming cusps or pinching off at the entry region.
2Productivity
If device geometries are shrunk and thermal budgets are reduced, then device density increases, but void-free filling of high aspect ratio spaces becomes increasingly difficult
Solution Approach 1:
The patent changes the deposition parameters by using flowable CVD chemistry at controlled temperatures and pressures, enabling uniform filling of increasingly narrow and deep gaps that result from scaled device geometries, achieving void-free filling even in high aspect ratio structures.
Solution Approach 2:
The patent uses a flowable material that copies the exact geometry of the gap being filled, flowing into all regions including corners and sidewalls to create a perfect replica of the gap space filled with uniform dielectric material, ensuring void-free filling in scaled geometries.
3Loss of time
If rapid delivery of process gases is used, then target concentration ratio is reached in minimal time, but process sensitivity to time-specific parameters increases
Solution Approach 1:
The patent implements feedback control by monitoring the actual gas concentrations and deposition rate in real-time, then adjusting the gas delivery rates to maintain the optimal reactant ratio despite rapid delivery conditions, reducing process sensitivity through active control.
Solution Approach 2:
The patent performs preliminary mixing and stabilization of the flowable CVD chemistry reagents before rapid delivery, ensuring that the correct stoichiometric ratio is pre-established, which reduces sensitivity to timing variations during the rapid delivery phase.
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 approach enables efficient filling of gaps with a flowable silicon-containing film that converts into a dielectric material, reducing voids and improving film quality by minimizing transition times and optimizing film properties such as composition and surface roughness.
Implementation Method 1
chemical vapor deposition processes for forming dielectric layers
Implementation Method 2
converting the flowable film into the dielectric material
Data Source
AI summary
Methods and apparatus for filling gaps on partially manufactured semiconductor substrates with dielectric material are provided. In certain embodiments, the methods include introducing a first process gas into the processing chamber and accumulating a second process gas in an accumulator maintained at a pressure level substantially highest than that of the processing chamber pressure level. The second process gas is then rapidly introduced from the accumulator into the processing chamber. An excess amount of the second process gas may be provided in the processing chamber during the introduction of the second process gas. Flowable silicon-containing films forms on a surface of the substrate to at least partially fill the gaps.