Amorphous Carbon Support for DRAM Capacitor Electrode Formation
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Solution Overview
Problem
Conventional methods for manufacturing capacitors in DRAM face challenges with the collapse of lower electrodes due to the removal of support base materials, particularly when using wet etching, which complicates the process and reduces yield, and dry etching struggles with removing thick silicon oxide without damaging the electrode.
Innovation Solution
The method involves forming a dense amorphous carbon film as a support base material using CVD, which is then removed by dry etching, preventing the collapse of lower electrodes and allowing for precise formation of deep and narrow holes with high aspect ratios without adding new support structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet etching is used to remove the support base material (silicon oxide), then the lower electrode collapses, but if dry etching is used, the thick silicon oxide cannot be removed without damaging the electrode
Solution Approach 1:
The patent changes the material parameter of the support base material from silicon oxide to amorphous carbon film. This material substitution enables the support to be removed by dry etching without collapsing the lower electrode, as carbon has different etching characteristics that allow selective removal while preserving the electrode structure.
Solution Approach 2:
The amorphous carbon film serves as a temporary, disposable support structure that is easily removed after serving its purpose. The carbon film provides necessary support during electrode formation and is then completely removed by dry etching, leaving no residue that would damage the electrode.
2Length of stationary object
If a thick silicon oxide film is used as support base material, then the deep hole can be formed, but the lower electrode collapses when the oxide is removed
Solution Approach 1:
The patent changes the material composition parameter from silicon oxide to amorphous carbon, which fundamentally alters the removal mechanism. Carbon can be selectively removed by dry etching processes that do not affect the lower electrode, whereas silicon oxide removal requires wet etching that causes electrode collapse.
Solution Approach 2:
The patent uses a composite structure where the amorphous carbon film serves as the support base material combined with the lower electrode structure. This composite approach allows the support material to be differentiated and removed selectively through material property differences.
3Productivity
If the aspect ratio of the deep hole is increased to achieve higher packing density, then the manufacturing difficulty increases remarkably
Solution Approach 1:
The patent changes the support material parameter to amorphous carbon film, which can be removed by dry etching. This enables the formation of deep holes with high aspect ratios without the manufacturing complexity associated with wet etching processes, as dry etching provides better control and no electrode collapse.
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 effectively prevents lower electrode collapse during the manufacturing of capacitors with high aspect ratios, maintaining structural integrity and precision, and avoids the complications of wet etching while enhancing heat resistance and reducing pattern deformation.
Implementation Method 1
depositing a dense amorphous carbon film as a support base material using CVD
Implementation Method 2
removed by dry etching
Data Source
AI summary
A method of manufacturing a stack capacitance type capacitor is provided, which prevents the problem that the capacitor cannot be formed because a lower electrode collapses with the external wall thereof exposed in forming the lower electrode of the capacitor in a deep hole formed in silicon oxide, and removing silicon oxide that is a support base material for the lower electrode using a solution containing hydrogen fluoride to expose the external wall of the lower electrode. According to the invention, the support base material in which a deep hole is formed is formed with an amorphous carbon film, the amorphous carbon film used as the support base material for the lower electrode is removed by dry etching after forming the lower electrode, and it is thereby possible to prevent the lower electrode from collapsing.