Flowable Dielectric Gap Fill via PECVD and In-Situ Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional deposition methods face challenges in filling high aspect ratio gaps with void-free dielectric material due to limitations in existing processes, leading to premature closure of gaps and formation of voids and seams, especially in small features with reentrant features.
Innovation Solution
The use of plasma-enhanced chemical vapor deposition (PECVD) to form a flowable polymerized film followed by in-situ or ex-situ treatments to convert the film into a dielectric material, allowing for a bottom-up fill of high aspect ratio gaps, with a tunable process to achieve desired electrical and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional PECVD processes are used to deposit dielectric material, then conformal film deposition is achieved, but voids and seams form in high aspect ratio gaps due to premature closure at the top
Solution Approach 1:
The patent changes the physical and chemical parameters of the deposition process by using a flowable polymer precursor instead of conventional solid dielectric materials. This allows the material to flow into high aspect ratio gaps before being converted to a solid dielectric, preventing void formation while maintaining conformal deposition characteristics
Solution Approach 2:
The patent employs a two-phase approach: first depositing a flowable polymer phase that can easily fill high aspect ratio gaps, then converting this polymer phase to a solid dielectric phase through thermal or plasma treatment. This phase transition enables complete gap filling without the limitations of direct solid material deposition
2Manufacturing precision
If HDP CVD is used for bottom-up gap fill, then directional deposition is achieved, but overhang and top-hat formation occur at the entry region
Solution Approach 1:
The patent changes the deposition parameters by using a flowable polymer precursor with different flow and deposition characteristics compared to conventional solid dielectric materials. This allows bottom-up filling behavior without the high momentum charged species that cause sputtering and redeposition in HDP CVD
Solution Approach 2:
The patent uses a temporary flowable polymer material that serves as a placeholder during deposition, which is then converted to the final dielectric material. This temporary material enables the desired deposition pattern without the harmful side effects of HDP CVD processes
3Manufacturing precision
If HDP CVD processes are used, then plasma etch steps are required to remove sidewall deposits and top-hats, but these etch steps increase process complexity and time
Solution Approach 1:
The patent extracts and eliminates the plasma etch step from the conventional HDP CVD process by using a flowable polymer precursor that deposits without forming top-hats or excessive sidewall deposits, thereby simplifying the overall process and reducing cycle time
Solution Approach 2:
The patent performs preliminary action by depositing the flowable polymer material in a controlled manner that prevents top-hat formation in the first place, eliminating the need for subsequent etch steps to remove these deposits
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 method effectively fills high aspect ratio gaps with a void-free dielectric material, reducing the need for costly and time-consuming etch steps, and allows for flexible thermal budgets, achieving films with desired properties such as low dielectric constants and improved mechanical strength.
Implementation Method 1
plasma-enhanced chemical vapor deposition (PECVD) of a flowable polymerized film in a gap
Implementation Method 2
the in-situ treatment may be a purely thermal or plasma treatment process
Implementation Method 3
the in-situ treatment may be a purely thermal or plasma treatment process
Data Source
AI summary
New methods of filling gaps with dielectric material are provided. The methods involve plasma-enhanced chemical vapor deposition (PECVD) of a flowable polymerized film in a gap, followed by an in-situ treatment to convert the film to a dielectric material. According to various embodiments, the in-situ treatment may be a purely thermal or plasma treatment process. Unlike conventional PECVD processes of solid material, which deposit film in a conformal process, the deposition results in bottom-up fill of the gap. In certain embodiments, a deposition-in situ treatment-deposition-in situ treatment process is performed to form dielectric layers in the gap. The sequence is repeated as necessary for bottom up fill of the gap. Also in certain embodiments, an ex-situ post-treatment process is performed after gap fill is completed. The processes are applicable to frontend and backend gapfill.