Crown-Shaped Capacitor Support Film Alignment Method
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Solution Overview
Problem
In semiconductor device manufacturing, misalignment during the formation of insulator beams and through holes can lead to lower electrodes not being connected to the beams, especially as devices miniaturize, causing structural instability and potential collapse of crown-shaped capacitors.
Innovation Solution
A method involving the sequential formation of sacrificial and support films, with specific openings created to maintain connection between crown-shaped electrodes and support films, allowing for the removal of sacrificial films while ensuring the electrodes remain connected to the support structures, thereby preventing collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulator beams are formed sequentially from the lower layer side, then the lower electrodes can be supported by the insulator beams, but misalignment between the insulator beam pattern and through hole position occurs, causing lower electrodes not to be connected to the beams
Solution Approach 1:
The patent forms openings in support films before forming the insulator beams. This preliminary action ensures that even if misalignment occurs during subsequent beam formation, the openings provide a tolerance zone that maintains connection between the lower electrodes and support structures. The openings are positioned to anticipate potential alignment variations.
Solution Approach 2:
The support films with pre-formed openings act as an intermediary layer between the lower electrodes and the insulator beams. These openings provide a mediating structure that compensates for alignment errors, allowing the system to maintain connectivity even when direct alignment between beams and electrodes is imperfect.
2Strength
If the number of insulator beams is increased to support higher aspect ratio capacitors, then the mechanical strength improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent divides the support function into multiple support films stacked at different heights, rather than using a single complex beam structure. Each support film provides localized support at specific levels, segmenting the overall support function into manageable layers that are easier to manufacture and align.
Solution Approach 2:
Instead of increasing the complexity of horizontal beam structures, the patent adds vertical dimensionality by stacking multiple support films at different heights. This dimensional approach provides enhanced mechanical support through the Z-axis without increasing in-plane structural complexity.
3Productivity
If the aspect ratio of crown-shaped capacitors is increased, then the device density improves, but the structural stability decreases and collapse risk increases
Solution Approach 1:
The support films are formed with openings before the capacitor structure is completed. This preliminary formation of support paths ensures that as the capacitor aspect ratio increases, the lower electrodes always have pre-established support routes to the substrate, preventing collapse during subsequent processing steps.
Solution Approach 2:
The multiple support films stacked at different heights provide beforehand cushioning support for high aspect ratio capacitors. This layered support structure anticipates the mechanical stresses that will occur with taller capacitor structures and provides distributed support to prevent collapse.
Data Source
AI summary
A device manufacturing method includes: sequentially forming a first sacrificial film, a first support film, a second sacrificial film, and a second support film on a semiconductor substrate; forming a hole to pass through these films; forming a crown-shaped electrode covering an inner surface of the hole and connected to the second support film and the first support film; forming a first opening in the second support film into a first pattern designed such that the connection between the crown-shaped electrode and the second support film is at least partially maintained; removing at least a part of the second sacrificial film through the first opening; forming a second opening in the first support film with use of the first opening; and removing the first sacrificial film through the second opening. This method is able to prevent misalignment of openings between the support films.