Non-Volatile Memory Shielding Against Insulator Impurities
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Solution Overview
Problem
Conventional semiconductor devices with non-volatile memories face issues with data storability due to impurities like water and mobile ions from the insulating layer reaching the charge storage part, leading to inaccurate data retrieval.
Innovation Solution
A semiconductor device is designed with a shielding part between the memory storage part and the insulating layer to prevent impurities from reaching the memory storage part, using a conductive wiring line layer as the shielding part and ensuring a specific protruding dimension and opening area to maintain data storability while allowing easy data deletion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an insulating layer containing inorganic insulating film and organic polymer film is provided above the non-volatile memory to protect and flatten the surface, then the surface flatness and protection are improved, but impurities including water and mobile ions from the insulating layer reach the charge storage part, causing data storability to deteriorate
Solution Approach 1:
A shielding part made of conductive material (such as aluminum wiring layer) is introduced as an intermediary layer between the insulating layer and the charge storage part. This shielding part blocks the migration path of impurities from the insulating layer to the charge storage part, while still allowing the insulating layer to provide its protective and flattening functions. The shielding part acts as a barrier that mediates between the protective insulating layer and the sensitive charge storage part.
Solution Approach 2:
The structure above the non-volatile memory is segmented into multiple functional layers: the insulating layer for protection and flattening, and a separate shielding part (can be a dedicated layer or existing wiring layer) for impurity blocking. This segmentation allows each layer to perform its specific function independently without interfering with each other's performance.
2Reliability
If a shielding part is provided between the memory storage part and the insulating layer to prevent impurities from reaching the memory storage part, then data storability is improved, but the device structure becomes more complex
Solution Approach 1:
The shielding part is designed to serve multiple functions: it acts as an impurity barrier between the insulating layer and charge storage part, and simultaneously functions as an existing wiring layer (such as aluminum layer) for electrical connections. By making the shielding part multi-functional, the need for additional dedicated shielding structures is eliminated, thus avoiding increased device complexity while still achieving improved data storability.
3Reliability
If the shielding part is made with sufficient protruding dimension to effectively block impurities, then data storability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The shielding effect is optimized by controlling the protruding dimension parameter of the shielding part relative to the charge storage part. By establishing an optimal range for this parameter (protruding dimension ≥ 5 times the distance between charge storage part and shielding part), effective impurity blocking is achieved while maintaining manufacturability. This parameter optimization balances shielding effectiveness with manufacturing precision requirements.
Data Source
AI summary
A semiconductor device that includes a substrate 37, a non-volatile memory (memory cell) 21 having a memory cell transistor (switching element) 33 and a floating gate electrode (memory storage part) 36, and a passivation insulating film (insulating layer) 40 and an organic polymer film (insulating layer) 41 both provided above the non-volatile memory 21, in which conductive wiring line layers (shielding part) 5a to 5c for shielding the floating gate electrode 36 are provided between the floating gate electrode 36 and both the passivation insulating film 40 and the organic polymer film 41 so that ions generated from the passivation insulating film 40 and the organic polymer film 41 can be prevented from reaching the floating gate electrode 36.