Capacitor Lower Electrode Leaning Prevention
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Solution Overview
Problem
In the fabrication of capacitors with high aspect ratios, the full dip-out process often results in leaning of lower electrodes due to limited space, making it difficult to form dielectric layers and upper electrodes, and the nitride floating capacitor structure provides insufficient support, leading to electrode leaning and potential contact during the dip-out process.
Innovation Solution
A method involving the formation of multiple upper electrodes, including a first upper electrode that fills the cylinder type lower electrodes, a second upper electrode surrounding the outer walls, and a third upper electrode connecting the first and second upper electrodes, with pillar parts that increase supporting force and prevent leaning, allowing for a thinner lower electrode design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the cylinder type lower electrode is decreased to secure the inner space, then the available space for dielectric layer and upper electrode increases, but the lower electrode becomes weaker and more prone to leaning during the full dip-out process
Solution Approach 1:
The support function is segmented between the lower electrode's own structure and the separately formed support layer. The support layer is formed as a distinct structure that provides reinforcement without increasing the lower electrode thickness, thus resolving the contradiction between maintaining strength and securing inner space.
Solution Approach 2:
The lower electrode structure is combined with a support layer to create a composite structure. This composite provides both the electrical function of the lower electrode and the mechanical support function, allowing the lower electrode to be thinner while maintaining overall structural strength during the dip-out process.
2Volume of moving object
If the thickness of the cylinder type lower electrode is decreased, then the inner space is secured, but the lower electrode is more likely to lean and touch adjacent electrodes during the full dip-out process
Solution Approach 1:
The support function is separated from the lower electrode itself and implemented through a distinct support layer. This segmentation allows the lower electrode to maintain its thin profile for space efficiency while the support layer independently provides positional stability and prevents leaning during the dip-out process.
Solution Approach 2:
The support layer acts as an intermediary structure between the lower electrode and the surrounding environment. It provides mechanical support and spacing that prevents the thin lower electrode from leaning or touching adjacent electrodes, thereby ensuring reliability without compromising the inner space.
3Stability of the object's composition
If the NFC structure is used to fixate lower electrodes, then leaning is prevented, but the space for forming the cylinder type lower electrode becomes limited in high degree integration
Solution Approach 1:
The support layer is applied locally and selectively to provide fixation only where needed for preventing lower electrode leaning. This localized approach maximizes the use of available space in high-density integration while maintaining the necessary stability of the lower electrode structure.
Data Source
AI summary
A method for fabricating a capacitor includes forming a mold structure over a substrate, wherein the mold structure has a plurality of open parts and has a mold layer stacked with a support layer; forming cylinder type lower electrodes in the open parts; forming a first upper electrode over an entire surface of a structure including the cylinder type lower electrodes to fill the cylinder type lower electrodes; defining a through hole that passes through portions of the first upper electrode and the support layer; removing the mold layer through the through hole and exposing the cylinder type lower electrodes; forming a second upper electrode to fill the through hole and spaces between the cylinder type lower electrodes; and forming a third upper electrode to connect the second upper electrode and the first upper electrode with each other.