Semiconductor Gate Element Waveguide Etching Profile Control
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Solution Overview
Problem
The manufacturing of waveguide structures in semiconductor integrated circuits faces challenges due to the need for precise control of opening profiles for effective light confinement and grating coupler integration, which is difficult to achieve with existing fabrication methods.
Innovation Solution
The semiconductor device incorporates a grating coupler structure within a semiconductor substrate, with a specific opening profile etched through inter-level dielectric material to ensure precise alignment and integration, using a combination of gate dielectric and electrode layers to control the etching process and enhance light coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching methods are used to create waveguide openings, then the manufacturing process is simple, but the opening profile precision and light confinement effectiveness are insufficient
Solution Approach 1:
The etching process is divided into multiple sequential steps with different etching agents and conditions. The first etching step uses a preliminary agent to create an initial opening, followed by a second etching step with a different agent to refine the profile and achieve the final precise dimensions required for effective light confinement.
Solution Approach 2:
A preliminary etching step is performed before the final etching to prepare the opening profile. This preliminary action creates a rough opening that is then refined in subsequent steps, ensuring that the final opening achieves the precise profile needed for optimal light confinement without requiring excessive precision in each individual etching step.
2Reliability
If the waveguide structure is integrated with grating couplers, then light coupling efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The grating coupler structure and waveguide are integrated into a single fabrication process sequence. The grating coupler is formed first through patterning and etching, followed by waveguide formation that directly interfaces with the grating coupler structure, ensuring precise alignment and efficient light coupling while maintaining manufacturing simplicity.
Solution Approach 2:
The grating coupler structure introduces localized periodic variations in the waveguide region to enhance light coupling. This local structural modification is applied only where needed for coupling, while the rest of the waveguide maintains its simple structure, thus improving light coupling efficiency without significantly increasing overall manufacturing complexity.
3Reliability
If the opening profile is optimized for light confinement, then device performance is improved, but the etching control difficulty increases
Solution Approach 1:
Multiple etching agents are used as intermediaries to achieve the desired opening profile. The first etching agent creates an initial profile, and the second etching agent refines it to the final precise dimensions. This multi-agent approach allows each agent to be optimized for specific profile requirements, making the overall process more controllable than using a single aggressive etchant.
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 allows for efficient light confinement and modulation, improving the manufacturing feasibility of waveguide structures by ensuring smooth and precise etching profiles that enhance device performance.
Implementation Method 1
a light is confined in the waveguide structure by a total internal reflection from the waveguide walls
Data Source
AI summary
A semiconductor structure is disclosed. The semiconductor structure includes: a substrate and a gate element over the substrate. The gate element includes: a gate dielectric layer over the substrate; a gate electrode over the gate dielectric layer; and a waveguide passing through the gate electrode from a top surface of the gate electrode to a bottom surface of the gate electrode. A manufacturing method of the same is also disclosed.