Low-Temperature Etching of Silicon Oxide Films
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Solution Overview
Problem
Existing etching methods for high aspect ratio holes in silicon oxide films at low temperatures result in significant differences in etch rates between laminated and single-layer films, leading to increased processing time and reduced productivity.
Innovation Solution
An etching method using a plasma generated from hydrogen-containing and fluorine-containing gases with controlled high-frequency electric power, where the lower electrode temperature is set to very low temperatures (≤ -30 °C) and the high-frequency electric power for biasing is optimized to match the etch rates of laminated and single-layer films, ensuring a ratio within ±20% of each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing etching methods are used for high aspect ratio holes in silicon oxide films at low temperatures, then high aspect ratio hole formation is achieved, but significant differences in etch rates between laminated and single-layer films occur, leading to increased processing time and reduced productivity
Solution Approach 1:
The patent applies parameter changes by optimizing the plasma generation conditions, specifically using a combined RF power system with different frequency components (e.g., 13.56 MHz and 27.12 MHz) to control the etch rate. By adjusting the power parameters and gas composition ratios, the etch rates for laminated and single-layer films are balanced, reducing processing time while maintaining high aspect ratio hole formation capability
Solution Approach 2:
The patent implements dynamics by using time-varying RF power application with multiple frequency components that can be independently controlled. The dynamic adjustment of power parameters during the etching process allows for real-time optimization of etch rates across different film structures, enabling simultaneous processing of laminated and single-layer films with matched etch rates
2Manufacturing precision
If existing etching methods are used for high aspect ratio holes in silicon oxide films at low temperatures, then high aspect ratio hole formation is achieved, but significant differences in etch rates between laminated and single-layer films occur, leading to increased processing time and reduced productivity
Solution Approach 1:
The patent changes physical parameters by introducing multi-frequency RF power control and optimizing gas composition ratios. These parameter changes enable precise control over the etch rate for different film structures, ensuring that laminated and single-layer films etch at matched rates, thereby reducing the overall processing time required
3Ease of manufacture
If existing etching methods are used, then etching of silicon oxide and silicon nitride films is performed, but significant differences in etch rates between different film structures occur, requiring separate processing and reducing productivity
Solution Approach 1:
The patent applies universality by creating a single etching process configuration that can simultaneously and effectively process both laminated films (silicon oxide and silicon nitride) and single-layer silicon oxide films. The multi-frequency RF power system and optimized gas composition enable this universal processing capability, eliminating the need for separate processing steps for different film structures and thereby improving productivity
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 significantly reduces processing time by aligning etch rates of laminated and single-layer films, improving productivity while maintaining high aspect ratio hole formation capabilities.
Implementation Method 1
generating a plasma from a hydrogen-containing gas and a fluorine-containing gas with high-frequency electric power for plasma generation
Implementation Method 2
etching a first film including a silicon oxide film and a silicon nitride film with the generated plasma
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An etching method includes generating a plasma from a hydrogen-containing gas and a fluorine-containing gas with high-frequency electric power for plasma generation. A first film including a silicon oxide film and a silicon nitride film is etched with the generated plasma in an environment at a temperature lower than or equal to -30 °C. The first etch rate of first etching that etches the first film and the second etch rate of second etching that etches a second film having a structure different from the structure of the first film are controlled, so that the difference between the first etch rate and the second etch rate is within ±20% of the first etch rate.