Oxidative Trim for High Aspect Ratio Capacitor Electrodes
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Solution Overview
Problem
In semiconductor memory devices, high aspect ratio capacitor columns can suffer from tapering and bulging issues during etching, leading to reduced space between capacitors and increased risk of shorts, which complicates the formation of stable and efficient memory cell structures.
Innovation Solution
A controlled oxidative trim using oxygen is performed on the electrode material to address the bulging and tapering issues, followed by a wet etch to remove the oxidation product, thereby maintaining a straighter electrode structure and increasing the space between capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high aspect ratio capacitor columns are formed to increase capacitance, then capacitance is improved, but structural integrity deteriorates due to tapering and bulging
Solution Approach 1:
An oxidative trim process is performed on the electrode material before final capacitor formation to proactively remove tapering and bulging defects. This preliminary action prevents structural integrity issues from developing during subsequent processing steps.
Solution Approach 2:
The patent applies controlled oxidation by adjusting parameters such as oxygen exposure time, temperature, and oxidation chemistry to selectively remove material from tapered and bulged regions while preserving the overall high aspect ratio structure.
2Quantity of substance
If extended etching is performed to form high aspect ratio structures, then capacitance is improved, but manufacturing precision deteriorates due to increased tapering and bulging
Solution Approach 1:
The patent replaces purely mechanical/physical etching processes with a chemical oxidation process to trim the electrode material. This substitution allows for more precise and controlled material removal without the tapering and bulging effects associated with extended etching.
Solution Approach 2:
The patent uses oxidative chemistry to rapidly and selectively remove material from the electrode structure. This accelerated oxidation process provides better control over material removal compared to traditional etching, maintaining manufacturing precision while achieving the desired high aspect ratio.
3Productivity
If capacitor columns are placed closer together to increase density, then productivity is improved, but reliability deteriorates due to increased short risk
Solution Approach 1:
The oxidative trim is performed in advance to proactively remove tapering and bulging that would otherwise cause capacitors to converge and short. This preliminary action ensures reliable electrical conduction even when capacitors are placed at high density.
Solution Approach 2:
The oxidation process applies a counter-action to prevent the harmful convergence of capacitor columns. By removing material from tapered regions, the process counteracts the tendency of columns to bulge toward each other, maintaining reliable spacing at high densities.
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 structural integrity and electrical conduction by maintaining a high aspect ratio while preventing underetch and pinching, thus improving the capacitance and reliability of memory cells.
Implementation Method 1
performing a controlled oxidative trim to an upper portion of the electrode material
Implementation Method 2
A wet etch may then be performed to etch away the resultant oxidation product
Data Source
AI summary
Methods, apparatuses, and systems related to trim a semiconductor structure using oxygen are described. An example method includes forming a support structure for a semiconductor structure having a first silicate material on a working surface. The method further includes forming a first nitride material on the first silicate material. The method further includes forming a second silicate material on the first nitride material. The method further includes forming a second nitride material on the second silicate material. The method further includes forming an opening through the semiconductor structure. The method further includes depositing an electrode material within the opening. The method further includes removing portions of the support structure. The method further includes performing a controlled oxidative trim to an upper portion of the electrode material.