Trench Isolation Layer Stack for Step Height Control
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Solution Overview
Problem
Current semiconductor manufacturing methods for trench isolation structures in memory devices face challenges such as damaged isolation structures, uneven surfaces, and difficulty in controlling the step height, leading to issues like current leakage and low programming speed, which affect the electrical performance and production yield of memory devices.
Innovation Solution
A semiconductor structure and manufacturing method involving a substrate with trenches, where an oxide layer and a protective layer are conformally formed, followed by a nitride layer and an insulating material layer, allowing for precise control of the step height between trench isolation features and the top surface, thereby preventing material loss and ensuring a complete and flat profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current manufacturing processes are used for trench isolation structures, then the manufacturing process is simple, but the isolation structures become damaged with uneven surfaces and uncontrolled step height
Solution Approach 1:
The trench isolation structure is divided into multiple segmented layers: oxide layer (first layer), protective layer (second layer), insulating material layer (third layer), and nitride layer (fourth layer). Each layer serves a specific function and can be independently controlled, enabling precise step height management while protecting the isolation structure from damage during manufacturing.
Solution Approach 2:
The protective layer is formed in advance before the insulating material is deposited. This preliminary protective layer prevents damage to the oxide layer and controls the step height before subsequent manufacturing steps, ensuring the isolation structure maintains its integrity throughout the fabrication process.
2Productivity
If isolation structures are reduced in size to increase integration density, then the degree of integration increases, but the isolation effect deteriorates and electrical properties worsen
Solution Approach 1:
The trench isolation structure uses composite materials with different properties: oxide layer for basic isolation, protective layer for structural integrity, insulating material for electrical isolation, and nitride layer for planarization. This composite approach maintains effective isolation even when the overall structure size is reduced for higher integration density.
3Ease of manufacture
If current trench isolation structures are formed, then the manufacturing process is straightforward, but current leakage and low programming speed occur
Solution Approach 1:
Different regions of the trench isolation structure have different material compositions and properties tailored to specific local requirements. The oxide layer provides base isolation, the protective layer ensures structural stability, the insulating material layer enhances electrical isolation, and the nitride layer provides surface planarization. This localized optimization eliminates current leakage and improves programming speed while maintaining manufacturing feasibility.
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
The method significantly improves the electrical properties and operating performance of semiconductor structures by accurately controlling the step height and preventing material loss, enhancing the reliability and yield of memory devices.
Implementation Method 1
an oxide layer conformally formed in the trench
Implementation Method 2
an oxide layer conformally formed in the trench
Implementation Method 3
a protective layer in the trench, and the protective layer is conformally formed on the oxide layer
Implementation Method 4
a protective layer in the trench, and the protective layer is conformally formed on the oxide layer
Implementation Method 5
a nitride layer in the trench, and a nitride layer is conformally formed on the protective layer
Implementation Method 6
a nitride layer in the trench, and a nitride layer is conformally formed on the protective layer
Data Source
AI summary
A semiconductor structure and its manufacturing method are provided. The semiconductor structure includes a substrate having a trench. The semiconductor structure also includes an oxide layer conformally formed in the trench and a protective layer formed in the trench. Also, the protective layer is conformally formed on the oxide layer. The semiconductor structure further includes an insulating material layer in the trench, and the insulating material layer is formed above the protective layer, wherein a top surface of the insulating material layer is higher than a top surface of the protective layer.