Semiconductor Optical Waveguide Recessed Cladding Design
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Solution Overview
Problem
Conventional semiconductor devices with insulating layers formed on the entire surface of the substrate face issues during electrostatic chucking, leading to charge accumulation, substrate cracking, and stress-induced deterioration of device characteristics.
Innovation Solution
A semiconductor device design featuring a semiconductor substrate with recessed areas for the cladding layer, which reduces charge accumulation and stress, and a method of manufacturing involving lamination of wafers to form optical waveguides and modulators, enhancing bonding strength and optical confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer is formed on the entire surface of the semiconductor substrate, then light confinement in the optical waveguide is improved, but charge accumulation occurs during electrostatic chucking, leading to substrate cracking and device deterioration
Solution Approach 1:
The insulating layer is segmented into two distinct regions: a first insulating layer formed only in the recess portion (providing light confinement where needed) and a second insulating layer formed on the entire surface (including the flat portion). This segmentation allows the first region to provide optical confinement while the second region prevents charge accumulation during electrostatic chucking, resolving the contradiction between light confinement and charge accumulation prevention.
2Loss of energy
If a thick insulating layer is formed to suppress light scattering, then optical loss is reduced, but stress on the semiconductor substrate increases, potentially causing cracking
Solution Approach 1:
The insulating layer structure implements local quality by providing different thicknesses and positions of insulating material in different regions. The first insulating layer in the recess portion provides sufficient thickness for light confinement and scattering suppression, while the overall distributed structure (with the second insulating layer on the flat portion) prevents excessive stress concentration on the substrate, thus reducing both optical loss and substrate cracking risk.
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 reduces charge accumulation and stress, improving the characteristics and yield of semiconductor devices by allowing for proper detachment from electrostatic chucks and minimizing optical losses.
Implementation Method 1
The insulating layer is a cladding layer for substantially confining light propagating inside the optical waveguide to the inside of the optical waveguide
Implementation Method 2
when the semiconductor substrate is to be held by, for example, electrostatic chucking, a large amount of charges is accumulated in the insulating layer. Therefore, the semiconductor substrate and the electrostatic chuck are fixed by the electrostatic force
Data Source
AI summary
A semiconductor device includes a semiconductor substrate having a first surface, a second surface opposite to the first surface, and having a first recess portion formed on the first surface, a first cladding layer located in the first recess portion, and a first optical waveguide formed on the first cladding layer. The first optical waveguide overlaps with the first cladding layer in plan view.