Probe Apparatus Optical Target Mark Alignment
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Solution Overview
Problem
Conventional probe apparatuses for semiconductor devices face challenges in position alignment accuracy and throughput due to the use of mechanical targets, which are prone to malfunctions, generate particles, and require complex mechanisms, while optical alignment methods require multiple steps and reduce efficiency.
Innovation Solution
A probe apparatus using an optical unit to align a pair of cameras by projecting an optical target mark onto the image forming units of both cameras simultaneously, allowing for simultaneous image pickup and reducing the need for mechanical targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical target is used for position alignment of cameras, then the alignment can be performed, but the device complexity increases and reliability decreases due to moving parts and potential malfunctions
Solution Approach 1:
The patent replaces the mechanical target with an optical target mark that is stationary and illuminated by a light source. The first camera captures the optical target mark through an optical system, eliminating the need for mechanical movement and parts, thereby reducing device complexity and improving reliability.
Solution Approach 2:
The patent uses an optical target mark that creates an optical image captured by the camera, replacing the physical mechanical target. This optical copy approach eliminates mechanical components while preserving the alignment function, reducing complexity and improving reliability.
2Ease of manufacture
If a mechanical target is used for position alignment, then the alignment can be performed, but manufacturing cost increases and ease of manufacture decreases due to complex driving mechanisms
Solution Approach 1:
The patent replaces the mechanical target with an optical target mark that is stationary and illuminated by a light source. The first camera captures the optical target mark through an optical system, eliminating the need for mechanical movement and parts, thereby reducing device complexity and improving reliability.
Solution Approach 2:
The patent uses an optical target mark that creates an optical image captured by the camera, replacing the physical mechanical target. This optical copy approach eliminates mechanical components while preserving the alignment function, reducing complexity and improving reliability.
3Productivity
If conventional optical alignment methods are used where spot light or two-dimensional pattern is projected, then alignment can be performed, but throughput decreases because both cameras cannot simultaneously recognize the target
Solution Approach 1:
The patent introduces a beam splitter that divides the optical path, allowing the optical target mark to be simultaneously imaged by both the first camera and the second camera. This dimensional change in the optical path enables parallel recognition by both cameras, improving throughput and reducing alignment time.
Solution Approach 2:
The beam splitter acts as an intermediary that divides the optical path from the optical target mark to both cameras simultaneously. This intermediary component enables both cameras to capture the target at the same time, eliminating sequential alignment steps and improving productivity.
4Measurement precision
If a glass plate with target mark is used in mechanical target, then alignment can be performed, but measurement precision decreases due to refraction errors from glass thickness variations
Solution Approach 1:
The patent extracts and eliminates the glass plate from the alignment system by using a stationary optical target mark without a glass substrate. This removes the source of refraction errors caused by glass thickness variations, thereby improving measurement precision of the position 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 enables faster and more accurate position alignment, reducing the complexity and cost of the alignment process, improving the overall efficiency of the probe test by eliminating the need for mechanical targets and simplifying the alignment mechanism.
Implementation Method 1
a projection optical unit including an optical system that projects an optical target mark, used in a position alignment of the first and the second imaging device, onto each of image forming units of the first and the second imaging device at the same time
Data Source
AI summary
A probe apparatus includes a stage, a first and a second imaging device, a first and a second imaging optical unit, and a projection optical unit. The stage is movable in horizontal and vertical directions. The first imaging device picks up an image of a probe needle which is made to contact with an electrode of a device formed on a surface of the substrate. The first and second imaging optical units include optical systems for performing an image pickup by using the first and second imaging devices, respectively. The second imaging device picks up an image of the electrode held on the stage. The projection optical unit includes an optical system that projects an optical target mark, used in a position alignment of the first and the second imaging device, onto each of image forming units of the first and second imaging devices at the same time.