Insulating Layer Refractive Index Gradient for Crack Prevention
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Solution Overview
Problem
The formation of insulating layers in semiconductor devices is prone to cracking or voids due to mismatched contraction stresses during heat treatment, as high pressure improves embeddability but increases cracking risk, while low pressure reduces cracking but leads to void formation.
Innovation Solution
A semiconductor device design featuring a first insulating layer with a higher refractive index than a second insulating layer, where the first layer is difficult to contract and the second layer is easy to contract, preventing excessive stress and void formation, and a manufacturing method involving sequential deposition under different pressures to achieve this configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the insulating layer is formed under high pressure, then the embeddability of the insulating material into the trench is improved, but the insulating layer is prone to cracking during heat treatment
Solution Approach 1:
The insulating layer is divided into multiple layers (first insulating layer and second insulating layer) with different refractive indices and contraction characteristics. The first insulating layer has higher refractive index and lower contraction, while the second insulating layer has lower refractive index and higher contraction, allowing each layer to accommodate different stress conditions and prevent cracking
Solution Approach 2:
The patent changes the physical parameters of the insulating layers by controlling the deposition pressure for each layer. The first insulating layer is formed under first deposition conditions (resulting in higher refractive index), and the second insulating layer is formed under second deposition conditions (resulting in lower refractive index), creating a gradient structure that manages contraction stress
2Reliability
If the insulating layer is formed under low pressure, then the insulating layer is less prone to cracking during heat treatment, but voids are generated in the insulating layer
Solution Approach 1:
The insulating layer is segmented into multiple layers with different formation pressures. The first insulating layer is formed under higher pressure to ensure good embeddability and avoid voids, while the second insulating layer is formed under lower pressure to reduce contraction stress and prevent cracking
Solution Approach 2:
The deposition pressure parameter is changed between forming the first and second insulating layers. The first layer uses higher pressure for better material embeddability, while the second layer uses lower pressure to reduce contraction, creating a balanced structure that avoids both voids and cracks
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 solution effectively prevents cracking and void formation in insulating layers, ensuring a stable semiconductor device with improved embeddability and enhanced voltage resistance.
Implementation Method 1
forming the insulating layer under a predetermined pressure and then performing heat treatment thereon
Implementation Method 2
makes it easy for the insulating material to contract in the heat treatment step
Data Source
AI summary
Described herein is a semiconductor device comprising: a semiconductor substrate; a trench provided at a surface of the semiconductor substrate; a first insulating layer covering an inner surface of the trench; and a second insulating layer located at a surface of the first insulating layer in the trench. A refraction index of the first insulating layer is larger than a refraction index of the second insulating layer.