Semiconductor Capacitor Structure Preventing Internal Electrode Bending
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Solution Overview
Problem
In the manufacturing of Dynamic Random Access Memory (DRAM), internal electrodes tend to bend and cause short circuits due to stress generated by the removal of the sacrifice layer, especially when the capacitor via has a large height, leading to capacitance value issues.
Innovation Solution
A method is developed to form a semiconductor structure by creating a semiconductor structure with a base, external electrode layers, a dielectric layer, internal electrode layers, and conductive layers, where the external electrode layers and dielectric layers support the internal electrode layers to prevent bending and short circuits, involving specific etching processes and layer formations to maintain mechanical stability and uniform morphology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacitor via has a large height to increase capacitance value, then the capacitance value is improved, but the internal electrode bends and causes short circuit
Solution Approach 1:
The support layer is formed on the base before forming the capacitor via, providing preliminary structural support. The external electrode layers are formed on the sidewalls of the capacitor via before filling the internal electrode, creating a support structure that prevents bending during subsequent processing steps.
Solution Approach 2:
The external electrode layers act as intermediary structures between the support layer and the internal electrode layer. These intermediary layers provide mechanical support to the internal electrode, preventing it from bending while maintaining the required capacitance value through the via height.
2Ease of manufacture
If the internal electrode is formed without external support, then the manufacturing process is simplified, but the internal electrode bends due to stress from sacrifice layer removal
Solution Approach 1:
The external electrode layers are formed on the sidewalls of the capacitor via before the internal electrode is deposited. This preliminary action creates a support structure that maintains internal electrode straightness during and after the sacrifice layer removal process, without significantly complicating the manufacturing flow.
Solution Approach 2:
The formation of external electrode layers changes the mechanical parameters of the capacitor structure, adding structural support that counteracts the stress-induced bending. This parameter change (adding sidewall electrodes) maintains ease of manufacture while improving structural stability during the critical removal of the sacrifice layer.
Data Source
AI summary
A semiconductor structure and a method for forming semiconductor structure are provided. The method includes: after a plurality of capacitor vias are formed in a support layer and a sacrifice layer, external electrode layers are formed on sidewall surfaces of the capacitor vias; a dielectric layer is formed on a sidewall surface of each external electrode layer; remaining sacrifice layer between the external electrode layers is removed to form a cavity at a position where remaining sacrifice layer has been removed; an internal electrode layer is formed on a surface of the dielectric layer and a bottom surface of each capacitor via; a first conductive layer completely filling the cavity is formed, where the first conductive layer is in contact with a respective one of the external electrode layers; and a second conductive layer completely filling a remaining part of each capacitor via is formed on the internal electrode layer.