Capacitor Electrode Leaning Prevention via Halogen Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in manufacturing thin and long cylindrical capacitor electrodes for semiconductor devices is the inclination or 'leaning' caused by wet etching methods, which is costly and damages support films, and lacks selective etching precision.
Innovation Solution
A method involving chemical transformation of silicon oxide films into reaction products using a halogen-containing gas, followed by post heat treatment to vaporize the reaction products, avoiding the use of wet etching and support films, thereby preventing electrode leaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet etching method is used to remove silicon oxide film, then the etching process can be performed, but the capacitor electrode becomes inclined (leaning) and may fall down
Solution Approach 1:
The invention changes the etching method from wet etching to a two-step process involving chemical reaction at low temperature (≤40°C) followed by thermal decomposition at high temperature (100-400°C). This parameter change in temperature and chemical mechanism eliminates surface tension effects that cause electrode leaning, while achieving complete oxide film removal.
Solution Approach 2:
The invention utilizes phase transition by transforming the silicon oxide film into a reaction product through chemical reaction, then removing it through thermal decomposition (solid to gas phase transition). This phase transition approach avoids liquid contact that causes surface tension and electrode leaning.
2Reliability
If a support film made of SiN is provided between capacitor electrodes to prevent leaning, then electrode stability improves, but the manufacturing process becomes more complex and costly
Solution Approach 1:
The invention extracts and eliminates the need for the support film by fundamentally changing the etching approach. Instead of adding a support film to prevent leaning, the method removes the root cause of leaning by avoiding wet etching entirely, thus simplifying the process while maintaining electrode stability.
Solution Approach 2:
The invention replaces the expensive and complex support film structure with a simple temperature-controlled chemical process. The transient reaction products are easily removed through thermal decomposition, eliminating the need for permanent support structures.
3Ease of manufacture
If conventional wet etching method is used, then the etching can be performed, but selective etching is difficult and the support film may be damaged
Solution Approach 1:
The invention applies local quality by using a two-step process with different temperature conditions. The first step (low temperature) selectively transforms the oxide film without affecting other materials, and the second step (high temperature) selectively removes only the transformed reaction product, achieving precise selective etching.
Solution Approach 2:
The invention performs preliminary action by first transforming the silicon oxide film into a reaction product through chemical reaction before removal. This preliminary transformation step enables selective removal in the subsequent thermal decomposition step without damaging other structures.
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 allows for selective removal of silicon oxide films without leaning, ensuring the reliability and precision of capacitor electrode manufacturing, improving the manufacturing process by avoiding the limitations of wet etching.
Implementation Method 1
transforming a silicon oxide film into a reaction product by supplying a gas containing a halogen element to chemically react with the silicon oxide film
Implementation Method 2
removing the silicon oxide film transformed to the reaction product by heating
Implementation Method 3
removing the reaction product by heating
Data Source
AI summary
A method for manufacturing a capacitor electrode by removing a silicon oxide film on a surface of a substrate, including: transforming the silicon oxide film into a reaction product by supplying a gas containing a halogen element to chemically react with the silicon oxide film while controlling temperature of the substrate to a first process temperature; and removing the silicon oxide film transformed to the reaction product while controlling the temperature of the substrate to a second process temperature higher than the first process temperature. The silicon oxide film is a BPSG film.