Photonic Integrated Circuit Wafer-Level Testing via Test Waveguide
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Solution Overview
Problem
The need for high-speed signal transmission in electronic devices is hindered by physical limitations in electrical signal transmission through copper lines, prompting the development of photonic integrated circuit devices for optical signal transmission, which require effective testing and fabrication methods to ensure reliability.
Innovation Solution
A photonic integrated circuit device with a semiconductor substrate featuring chip regions and scribe lines, including an optical transmitter, optical receiver, and a test optical waveguide for wafer-level testing, allowing electrical testing of optical components before dicing into individual devices, facilitating improved reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wafer-level testing is implemented for photonic integrated circuit devices, then reliability is improved through early defect detection, but device complexity increases due to the need for test optical waveguides and substrate-level testing infrastructure
Solution Approach 1:
The patent combines the test optical waveguide with the functional optical waveguide structure, allowing the same waveguide to serve both testing and operational purposes. This merging approach enables wafer-level testing functionality to be integrated into the existing device architecture rather than adding separate testing infrastructure, thereby improving reliability while minimizing the increase in device complexity.
Solution Approach 2:
The test optical waveguide is designed to perform multiple functions: it serves as both a testing pathway for wafer-level characterization and as part of the functional optical circuit. This multi-functionality allows a single structure to fulfill both testing and operational requirements, reducing the need for additional dedicated testing components and infrastructure.
2Ease of operation
If test optical waveguides are provided on the semiconductor substrate, then ease of operation is improved through electrical testing capability, but manufacturing precision requirements increase due to alignment and integration constraints
Solution Approach 1:
The test optical waveguide is merged with the functional waveguide routing, allowing both testing and operational optical paths to share the same physical infrastructure. This integration reduces the number of separate waveguide structures that would need to be precisely aligned and manufactured, thereby easing operational testing while reducing manufacturing precision requirements.
Solution Approach 2:
The test optical waveguide is designed to be optically coupled to both the optical transmitter and optical receiver on the same substrate, creating an equipotential testing environment where all components operate at the same integration level. This approach simplifies the testing process by eliminating the need for external optical probing and alignment, thereby improving ease of operation while managing manufacturing precision through standardized substrate-level integration.
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
Enables reliable wafer-level testing and separation of photonic integrated circuit devices, overcoming the limitations of electrical signal transmission by allowing optical signal testing without external optical probes, thus enhancing the reliability and speed of photonic integrated circuit devices.
Implementation Method 1
A test optical waveguide is provided, which is disposed on the semiconductor substrate. This test optical waveguide connects the optical transmitter to a photodetector provided on the optical receiver.
Implementation Method 2
The photodetector may include a cladding layer on the substrate, a silicon core layer on the cladding layer and a germanium pattern on the silicon core layer. The test optical waveguide may be optically coupled to the silicon core layer.
Data Source
AI summary
A photonic integrated circuit device includes a semiconductor substrate (e.g., wafer) having a chip region therein, which is bounded on at least one side thereof by a scribe line. The chip region includes an optical transmitter, an optical receiver and a test optical waveguide. This test optical waveguide is coupled to the optical transmitter and the optical receiver and overlaps the scribe line. During a substrate dicing operation, a portion of the test optical waveguide overlapping the scribe line is removed.