Selective Silicon Oxide Etching via Cyclic Halogen and Thermal Processing
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Solution Overview
Problem
Current methods for selectively etching silicon oxide films face challenges in achieving uniformity and selectivity, particularly with the miniaturization of semiconductor patterns, as they often result in non-uniform device characteristics and inefficiencies due to isotropic etching, low selectivity, and charging damage.
Innovation Solution
A method involving repeated etching and thermal processes in the same reactor, using halogen and basic gases to react with the silicon oxide film, with preheating and controlled temperature adjustments to enhance etch uniformity and selectivity, and reduce processing time and heating member wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate low-temperature chemical processing chamber and high-temperature thermal processing chamber are used, then reaction product removal is achieved, but apparatus size increases and processing time is delayed
Solution Approach 1:
The patent combines the low-temperature chemical processing and high-temperature thermal processing functions into a single etching apparatus. The apparatus can switch between etching mode (room temperature to 100°C) and thermal processing mode (up to 400°C), eliminating the need for separate chambers and wafer transfer, thus reducing processing time while maintaining reaction product removal capability.
Solution Approach 2:
The patent employs periodic switching between etching process and thermal processing within the same chamber. The etching is performed at low temperature, followed by periodic thermal processing to remove reaction products, achieving both reliability and productivity through cyclic operation.
2Productivity
If repeated etching and thermal processes are performed in the same reactor, then throughput is enhanced, but heating member operating time increases
Solution Approach 1:
The patent minimizes the duration of high-temperature thermal processing steps while maintaining their effectiveness for reaction product removal. By optimizing the thermal processing time and temperature, the patent achieves thorough product removal with minimal heating member exposure, thus extending lifespan while maintaining high throughput through repeated cycles.
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 enhances etch uniformity and selectivity, reduces processing time, and increases the lifespan and efficiency of heating members by minimizing exposure to high temperatures and optimizing temperature differences between etching and thermal processes.
Implementation Method 1
supplying halogen gas and basic gas into the reactor and allowing the halogen gas and the basic gas to react with the silicon oxide film formed on the wafer to generate a reaction product on the wafer
Implementation Method 2
heating the wafer with the reaction product generated thereon at a second temperature to remove the reaction product
Implementation Method 3
cooling the wafer at the first temperature
Data Source
AI summary
The present invention relates to a method for selectively etching a silicon oxide film in a semiconductor manufacturing process and comprises: a step of introducing a substrate having a silicon nitride film and a silicon oxide film to a substrate support part inside a reactor; a step of heating the substrate introduced into the reactor, so as to maintain a first temperature; a first step of supplying halogen gas and basic gas to the inside of the reactor, while the first temperature is maintained, so as to be reacted with the silicon oxide film formed on the substrate, thereby forming a reaction product on the substrate; a second step of heating the substrate, having the reaction product, up to a second temperature so as to remove the reaction product; a third step of cooling the temperature of the substrate down to the first temperature; and a step of repetitively performing the first step to the third step a preset number of times.