Semiconductor Capacitor Stack Fabrication With Preformed Supporter Holes
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Solution Overview
Problem
As semiconductor devices with increased capacitor height suffer from reliability issues such as bending or inclination, existing methods fail to effectively support the lower electrode during fabrication, leading to compromised device reliability.
Innovation Solution
A method is introduced that involves forming supporter holes in advance to facilitate the dip-out process, preventing damage to the lower electrode by allowing for a single dip-out process to remove all mold layers, thereby maintaining alignment and reducing etching difficulty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the height of the capacitor is increased to increase capacitance within a limited planar area, then the capacitance is improved, but the reliability of the DRAM device deteriorates due to bending or inclination of the capacitor
Solution Approach 1:
Supporter holes are formed in advance through the stack structure before the lower electrode is deposited. This preliminary action provides a pathway for etchant to reach and remove the mold layer, preventing the lower electrode from adhering to the mold layer and causing bending or inclination during subsequent processing.
2Ease of manufacture
If multiple dip-out processes are performed to remove mold layers sequentially, then the mold layers are removed, but the lower electrode may be damaged and the process complexity increases
Solution Approach 1:
Supporter holes are formed in advance to create etchant pathways, enabling a single dip-out process to remove all mold layers simultaneously. This eliminates the need for multiple sequential dip-out processes and prevents lower electrode damage that would occur with repeated handling.
Solution Approach 2:
The stack structure is segmented by forming holes through it, allowing etchant to access and remove different mold layers at the same time rather than requiring sequential removal of each layer.
3Reliability
If supporter holes are formed in advance, then the dip-out process is facilitated and lower electrode damage is prevented, but the manufacturing process complexity increases
Solution Approach 1:
Supporter holes are formed in advance as a simple preparatory step that enables subsequent process simplification. Although this adds one process step, it eliminates the need for multiple dip-out processes and lower electrode re-alignment operations, resulting in net process simplification.
Data Source
AI summary
Present invention relates to a method of fabricating a semiconductor device that can facilitate the processes of etching a supporter and removing a mold layer. According to the present invention, a method of fabricating a semiconductor device semiconductor device comprises: sequentially forming a substructure over a substrate and a etch stop layer over the substructure; forming a stack structure of alternately stacked mold layers and supporter layers over the etch stop layer; forming a plurality of supporter holes in the stack structure exposing the etch stop layer; forming a sacrificial layer filling each of the plurality of the supporter holes; forming a plurality of lower electrode openings exposing the substructure by etching the sacrificial layer and the stack structure; and forming a lower electrode inside the plurality of lower electrode openings.