Cylinder-Type Capacitor Structure Manufacturing Method
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Solution Overview
Problem
The challenge in manufacturing semiconductor devices with cylinder-type capacitor structures is the difficulty in controlling the bowing shape of high-aspect-ratio cylinder holes during dry etching, which leads to issues with maintaining the distance between holes and preventing lower electrodes from falling or breaking during wet processing, resulting in short circuits or operational defaults.
Innovation Solution
The method involves forming embedded insulating films in grooves within the inter-layer insulating film to prevent bowing of cylinder holes and coupling lower electrodes with each other to prevent them from falling, using a process that includes forming grooves, embedding insulating films, creating cylinder holes, forming lower electrodes with a pipe shape, and covering them with capacitance and upper electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If dry etching is used to form high-aspect-ratio cylinder holes for finer memory cells, then the occupied area of the capacitor is reduced, but the cylinder holes develop a bowing shape that makes it difficult to control the distance between holes and the short margin of the lower electrode
Solution Approach 1:
The patent applies preliminary action by forming a mandrel structure before creating the cylinder holes. The mandrel serves as a sacrificial template that defines the precise position and shape of the cylinder holes in advance. By preparing this guiding structure beforehand, the bowing issue during etching is prevented and the distance between holes is controlled accurately, resolving the manufacturing precision problem while maintaining the reduced occupied area.
Solution Approach 2:
The patent introduces a mandrel as an intermediary element that mediates between the etching process and the final cylinder hole structure. The mandrel acts as a temporary supporting structure during fabrication that prevents the formation of bowing shapes. After the lower electrode is formed, the mandrel is removed, leaving precisely formed cylinder holes without distortion. This intermediary structure resolves the contradiction by enabling precise control during manufacturing while achieving compact capacitor design.
2Ease of manufacture
If the inter-layer insulating film is removed by wet processing after forming the lower electrode, then the capacitor structure is completed, but the lower electrode tends to fall or break causing short circuits or operational defaults
Solution Approach 1:
The patent applies beforehand cushioning by forming a support film that covers the lower electrode before the inter-layer insulating film is removed. This support film acts as a protective cushion that prevents the lower electrode from falling or breaking during the wet processing step. The support film is designed to be removed afterward, having served its protective function. This resolves the reliability issue by preventing electrode damage while maintaining ease of manufacture through the standard wet processing removal step.
3Quantity of substance
If the aspect ratio of the lower electrode is increased to increase the surface area of the electrode, then the capacitor capacity is increased, but the lower electrode becomes more prone to falling during wet processing
Solution Approach 1:
The patent applies beforehand cushioning by introducing a support film that specifically protects the high-aspect-ratio lower electrode during wet processing. The support film is formed to cover and reinforce the delicate electrode structure, allowing it to maintain its high aspect ratio for increased capacity without falling or breaking during subsequent processing. This enables the patent to achieve high capacitor capacity while maintaining reliability by preventing electrode failure during manufacturing.
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 bowing of cylinder holes and maintains the integrity of lower electrodes, increasing capacitor capacity by utilizing both inner and outer surfaces of the electrodes and reducing the risk of short circuits, thereby enhancing the reliability of semiconductor devices.
Implementation Method 1
a plurality of cylinder holes 102 are arranged by means of dry etching
Implementation Method 2
the inter-layer insulating film 101 is removed by means of wet processing
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming an inter-layer insulating film; arranging a plurality of grooves in a surface layer of the inter-layer insulating film; forming embedded insulating films which are embedded in the grooves; arranging a plurality of holes in the inter-layer insulating film and between the embedded insulating films, in a manner such that each hole between the embedded insulating films partially overlaps therewith; forming lower electrodes, each of which has a bottom and a side face, and covers the bottom and side faces of the corresponding hole; forming a capacitance insulating film which covers the lower electrodes; and forming an upper electrode which further covers the capacitance insulating film.