Phosphoric Acid Temperature Cycling for 3D Memory Etching
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Solution Overview
Problem
The precipitation of silica during the etching of substrates using phosphoric acid can hinder the formation of predetermined structures, particularly in the production of three-dimensional memory devices, leading to processing inefficiencies and potential defects.
Innovation Solution
A substrate processing method and device that utilize temperature control to manage the etching process, alternating between two or more temperatures in the processing tank to optimize the etching rate and prevent silica precipitation, allowing for precise control of the phosphoric acid temperature to suit the etching requirements of the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If phosphoric acid is used to etch substrates at high temperature, then the etching rate is improved, but silica precipitation occurs which hinders structure formation
Solution Approach 1:
The patent applies periodic temperature variation during the etching process, alternating between high temperature (for fast etching) and low temperature (to prevent silica precipitation). This periodic action allows the system to achieve both high etching rates and prevent harmful silica precipitation by cycling through different thermal conditions during substrate processing.
Solution Approach 2:
The patent changes the temperature parameter dynamically during the etching process. By varying the temperature between different stages of etching, the system optimizes the etching rate while controlling silica precipitation. The temperature parameter is adjusted based on the specific etching requirements and substrate conditions.
2Productivity
If temperature is increased to improve etching rate, then processing efficiency is improved, but silica precipitation increases which reduces manufacturing precision
Solution Approach 1:
The patent implements periodic temperature cycling where the temperature is raised to improve etching efficiency and then lowered to prevent silica precipitation that would compromise structure precision. This periodic action enables the system to maintain both high productivity and manufacturing precision by alternating between aggressive etching conditions and controlled precipitation conditions.
Solution Approach 2:
The patent applies preliminary low-temperature treatment before high-temperature etching to prevent initial silica precipitation, then follows with controlled high-temperature etching. This preliminary action prepares the substrate and processing environment to avoid precipitation issues while maintaining etching precision.
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 enhances the processing efficiency by preventing silica precipitation, improving the etching rate, and reducing processing time, thereby facilitating the production of substrates with complex microstructures like three-dimensional memory devices.
Implementation Method 1
a temperature control unit that controls a temperature of the phosphoric acid. The temperature control unit controls the temperature of the phosphoric acid stored in the one or more processing tanks to perform processing of the substrate using phosphoric acid set to a first temperature
Data Source
AI summary
A substrate processing method includes a first processing step of processing a substrate using phosphoric acid set to a first temperature in a processing tank, and a second processing step of processing the substrate using phosphoric acid set to a second temperature in the processing tank.