Ferroelectric Capacitor Protection via Multi-Layer Insulating Films
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Solution Overview
Problem
Ferroelectric capacitors in semiconductor devices are prone to deterioration due to the ingress of reducing substances like hydrogen and water, which degrade their characteristics, and heat treatment can lead to element evaporation, further compromising performance.
Innovation Solution
A method involving the formation of a semiconductor device with a ferroelectric capacitor covered by a three-layer insulating film structure: a first layer with oxygen, hydrogen, and water permeability, followed by a second layer with reduced permeability, and a third layer to prevent further contamination and evaporation, all formed using specific materials and processes to maintain capacitor integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single protection film is formed over the ferroelectric capacitor, then the structure is simple, but it cannot simultaneously prevent element evaporation and block reducing substances effectively
Solution Approach 1:
The protection film is divided into three distinct layers: a first protection film (aluminum oxide) that blocks element evaporation during heat treatment, a second protection film that provides additional barrier properties, and a third protection film that prevents reducing substance ingress. Each layer serves a specific protective function, collectively achieving comprehensive protection that a single film cannot provide.
Solution Approach 2:
The patent employs a composite multi-layer film structure combining different materials with complementary properties. The first protection film uses aluminum oxide for its oxygen permeability and element blocking capability, while subsequent layers use materials optimized for reducing substance barrier properties, creating a composite protective system that leverages the strengths of each material.
2Reliability
If the first protection film has high oxygen permeability to supply oxygen during heat treatment, then oxygen supply is improved, but reducing substances can also pass through more easily
Solution Approach 1:
The protective function is segmented across three layers: the first layer (aluminum oxide) provides oxygen permeability for heat treatment while blocking elements, the second layer provides enhanced barrier properties, and the third layer specifically blocks reducing substances. This segmentation allows each layer to optimize for its specific function without compromising overall protection.
Solution Approach 2:
The second and third protection films act as intermediary layers between the ferroelectric capacitor and the external environment. These intermediate layers provide additional barrier functions that prevent reducing substances from reaching the ferroelectric capacitor, while the first layer maintains oxygen supply during heat treatment.
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 suppresses the deterioration of ferroelectric capacitors by controlling the passage of hydrogen and water while compensating for element loss during heat treatment, resulting in high-performance and high-quality semiconductor devices with improved ferroelectric capacitor characteristics.
Implementation Method 1
a first insulating film having a barrier property against a first element contained in the ferroelectric capacitor and having an oxygen permeability, a hydrogen permeability, and a water permeability
Implementation Method 2
a first insulating film having a barrier property against a first element contained in the ferroelectric capacitor and having an oxygen permeability, a hydrogen permeability, and a water permeability
Implementation Method 3
performing heat treatment in an oxidizing atmosphere after forming the first insulating film
Data Source
AI summary
A first-layer insulating film having a barrier property against a determined element contained in a ferroelectric capacitor as well as an oxygen permeability, a hydrogen permeability, and a water permeability is formed over a surface of the ferroelectric capacitor formed over a substrate. After that, heat treatment is performed in an oxidizing atmosphere. After the heat treatment, a second insulating film having a hydrogen permeability and a water permeability lower than those of the first-layer insulating film respectively is formed over a surface of the first-layer insulating film in a non-reducing atmosphere. A third-layer insulating film is formed over a surface of the second-layer insulating film. By doing so, degradation of a ferroelectric film under and after the formation of a semiconductor device having the ferroelectric capacitor is suppressed and deterioration in the characteristics of the ferroelectric capacitor is suppressed.