Optical Reference Beam Probe Alignment
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Solution Overview
Problem
Conventional probe alignment methods in laser trimming systems are cumbersome and lack precision, requiring manual iterative adjustments and physical fiducial references, which are prone to errors and limit throughput and accuracy, especially with finer device feature sizes.
Innovation Solution
A compact, high-speed laser processing system with integrated wafer probing and automated probe alignment using a dynamic optical reference beam, eliminating the need for physical fiducial references and enabling precise alignment of probe pins to wafer pads within tight tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional probe alignment methods using physical fiducial references are used, then alignment can be achieved, but the process becomes cumbersome and time-consuming requiring manual iterative adjustments
Solution Approach 1:
The patent replaces the mechanical/physical fiducial reference system with an optical reference beam system. Instead of using physical markers on the wafer that require manual alignment, the system uses a laser-generated optical reference beam that can be automatically detected and tracked by the probe card, enabling automated alignment without manual iterative adjustments.
Solution Approach 2:
The patent introduces an optical reference beam as an intermediary between the probe card and the wafer. This reference beam serves as a mediator that carries alignment information optically, allowing the probe card to determine its position relative to the wafer without direct mechanical contact or manual adjustment of physical fiducials.
2Measurement precision
If manual iterative adjustment steps are used for probe alignment, then alignment can be achieved, but the operator burden increases and precision is limited
Solution Approach 1:
The patent replaces manual mechanical adjustment mechanisms with an optical detection system. The probe card incorporates optical detectors that automatically sense the position of the optical reference beam, eliminating the need for operators to manually adjust probe positions while achieving higher precision through optical measurement capabilities.
Solution Approach 2:
The patent creates an optical copy or representation of the alignment reference through the laser beam. Instead of physically manipulating real fiducial markers, the system uses an optical field that can be precisely controlled and measured, allowing for more accurate alignment without the limitations of physical reference objects.
3Productivity
If physical fiducial references are used for calibration, then reference position can be determined, but errors are more prone and throughput is limited
Solution Approach 1:
The patent replaces physical fiducial references with an optical reference beam that is generated and controlled by the laser system itself. This eliminates errors associated with physical marker placement, wear, and misalignment, while enabling faster automated alignment that increases throughput without sacrificing reliability.
Solution Approach 2:
The patent makes the laser system multi-functional by using the same laser that performs trimming to also generate the optical reference beam for alignment. This integration eliminates the need for separate alignment equipment and physical fiducials, streamlining the process to improve both throughput and reliability through a unified system.
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 system achieves accurate and rapid alignment and processing of wafer devices, improving laser trimming efficiency by optimizing pulse energy control and maintaining stable trim rates for both coarse and fine adjustments, thereby enhancing overall processing precision and speed.
Implementation Method 1
detecting a position of the probe pin element in the reference field based at least in part on radiation from the optical reference beam
Data Source
AI summary
A laser processing system implements a method for aligning a probe element (e.g., a probe pin) with a device interface element (e.g., a contact pad of a circuit substrate). First, the laser processing system generates an optical reference beam at one or more predetermined positions to calibrate a reference field. The laser processing system then detects a position of the probe element in the reference field. The laser processing system also determines a relative position of the device interface element in the reference field. Based on the position of the probe element and the device interface element, the laser processing system then initiates alignment of the probe element and the device interface element. In one application, alignment of the probe element and the device interface element further includes contacting the probe element to the device interface element to make an electrical connection.