Gap-Fill Thin Film Deposition Without Voids or Fluorine Residue
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Solution Overview
Problem
Existing substrate processing methods, such as the deposition-etch-deposition (DED) and deposition-etch-H2 plasma treatment-deposition (DEHD) methods, face challenges in filling gaps in high aspect ratio structures without forming voids, due to issues like fluorine residue affecting film quality and deposition rate.
Innovation Solution
A substrate processing method involving a sequence of steps: forming a thin film, etching with a fluorine-containing gas, treating with a hydrogen-containing gas to remove fluorine-terminated sites, applying an inhibiting gas to the upper gap portion to suppress further deposition, and repeating these steps to ensure uniform gap filling without voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a deposition-etch-deposition (DED) method using NF3 gas is used to keep the gap inlet open, then void formation is prevented, but fluorine remains in the film causing decreased film formation rate and film quality
Solution Approach 1:
The patent extracts and removes fluorine residues from the film surface using hydrogen plasma treatment. The hydrogen plasma reacts with fluorine atoms to form volatile HF compounds that are removed from the structure, eliminating the harmful fluorine accumulation that degraded film quality and formation rate in conventional DED methods
Solution Approach 2:
The patent introduces hydrogen plasma as an intermediary treatment step between deposition and etching. This hydrogen plasma layer acts as a mediator that removes fluorine contaminants without damaging the underlying film structure, enabling subsequent high-quality deposition cycles
2Productivity
If hydrogen plasma treatment is applied to remove fluorine, then fluorine residues are eliminated, but hydrogen acts as hydrogen-terminated sites promoting deposition at film surface increasing deposition rate in upper area causing void formation
Solution Approach 1:
The patent applies selective nitrogen plasma treatment to the upper portion of the gap structure. This creates local quality differences where the upper area receives fluorine removal treatment while the lower area maintains hydrogen-terminated sites that promote deposition, preventing void formation by controlling deposition rates spatially
Solution Approach 2:
The patent changes the plasma treatment parameters by using nitrogen plasma instead of hydrogen plasma for the upper portion. This parameter change transforms the surface chemistry from hydrogen-terminated (promoting deposition) to nitrogen-terminated (inhibiting deposition), enabling precise control over deposition rates in different gap regions
3Device complexity
If simple deposition process is used to fill the gap, then process complexity is reduced, but voids are formed inside the gap
Solution Approach 1:
The patent segments the gap filling process into multiple alternating cycles of deposition, hydrogen plasma treatment, and nitrogen plasma treatment. This segmentation allows each step to perform its specific function optimally while maintaining overall process efficiency and preventing void formation through controlled deposition patterns
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 gaps without voids, enhances the gap filling rate, and improves film quality by removing fluorine residues and controlling deposition rates across the gap structure.
Implementation Method 1
a second step of etching a portion of the thin film by supplying a fluorine-containing gas onto the thin film
Implementation Method 2
a third step of supplying a hydrogen-containing gas onto the thin film, wherein the hydrogen-containing gas supplied during the third step may remove fluorine-terminated sites formed on a surface of the thin film by the second step
Implementation Method 3
a fourth step of supplying an inhibiting gas to an upper portion of the gap, wherein the inhibiting gas supplied during the fourth step removes the hydrogen-terminated sites on the thin film in the upper portion of the gap, thereby suppressing the formation of a thin film on the upper portion of the gap during the fifth step
Implementation Method 4
a first step of forming a thin film on a structure including a gap by performing a first cycle including supplying a first reaction gas on the structure
Data Source
AI summary
Provided is a substrate processing method capable of filling a film in a gap structure without forming voids or seams in a gap, the substrate processing method including: a first step of forming a thin film on a structure including a gap by performing a first cycle including supplying a first reaction gas and supplying a second reaction gas to the structure a plurality of times; a second step of etching a portion of the thin film by supplying a fluorine-containing gas onto the thin film; a third step of supplying a hydrogen-containing gas onto the thin film; a fourth step of supplying an inhibiting gas to an upper portion of the gap; and a fifth step of forming a thin film by performing a second cycle including supplying the first reaction gas and supplying a second reaction gas onto the thin film a plurality of times.