Wafer Test Alignment Using Intermediary Ports
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Solution Overview
Problem
The alignment of optical fibers with optical ports on wafers during wafer-level testing is sensitive to errors and time-consuming due to the need for precise positioning, which hampers the efficiency of testing optical integrated circuits.
Innovation Solution
A wafer test system that includes an input device for transmitting test signals, a measuring device to assess the alignment, and an alignment device to adjust the optical probe's position relative to the wafer, utilizing an alignment port with a wider area than the optical port and separated by a predetermined distance to facilitate quicker and more accurate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct alignment between optical fiber and optical port is performed, then alignment precision is improved, but alignment time increases significantly
Solution Approach 1:
An alignment port is introduced as an intermediary element between the optical fiber and the optical port. The alignment port has a larger area than the optical port, allowing the optical fiber to be aligned with the alignment port first (which is easier and faster), and then the alignment port guides the light to the optical port. This intermediary structure reduces the difficulty and time of direct precision alignment while maintaining alignment accuracy.
2Measurement precision
If optical fiber is directly aligned with optical port, then alignment accuracy is improved, but sensitivity to alignment errors increases
Solution Approach 1:
The alignment port serves as a buffer zone that reduces sensitivity to alignment errors.由于其较大的面积, it provides a larger tolerance range for alignment, so small misalignments do not cause significant performance degradation. The alignment port acts as an intermediary that guides light even when there are minor alignment errors, thereby reducing the harmful effects of alignment inaccuracies.
3Ease of operation
If alignment port with wider area is used, then ease of alignment is improved, but device complexity increases
Solution Approach 1:
The alignment port and optical port are merged into a single wafer structure, with the alignment port having a larger area than the optical port. This merging approach allows the alignment function and optical transmission function to be combined in one integrated structure, reducing the need for separate alignment mechanisms and thereby limiting the increase in device complexity while improving ease of alignment.
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 reduces sensitivity to alignment errors and significantly decreases the time required for alignment, enhancing the efficiency of wafer-level testing for optical integrated circuits.
Implementation Method 1
an optical waveguide connected between the alignment port and the output port to transmit the test signal to the output port
Implementation Method 2
an opto-electric converter configured to convert the test signal into an electrical signal
Implementation Method 3
an electro-optical converter configured to convert the test signal into an optical signal
Data Source
AI summary
A wafer test system includes an input device configured to transmit a test signal, a wafer including an optical port, an input port configured to receive the test signal, and an output port configured to output a result signal based on the test signal, a measuring device configured to measure the result signal, and an alignment device configured to align an optical fiber port of an optical probe with an alignment port based on the result signal and then align the optical fiber port with the optical port. The alignment port is the input port or the output port. The optical probe is configured to be the input device when the input port is the alignment port and the optical probe is configured to be the measuring device when the output port is the alignment port.