Probe Tip Position Detection via Mechanical Contact
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Solution Overview
Problem
Current methods for aligning probes with semiconductor wafers during electric characteristic inspection are time-consuming and lack accuracy, particularly in detecting the height of probe tips, which is crucial for reliable inspection and can be damaged by excessive needle pressure.
Innovation Solution
A method and apparatus that utilize a tip position detecting device with a sensor unit and a vertically movable contact member, applying a predetermined pressure to detect probe tip positions without bending the probes, and transferring needle marks onto a soft member for accurate alignment and inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a camera is used to detect probe tip positions, then tip positions can be detected, but the process takes a long time due to focusing requirements
Solution Approach 1:
The patent replaces the optical camera-based detection system with a mechanical contact-based detection system. A detection probe with a contact member physically touches the target probe tip, and a displacement sensor detects the positional change mechanically, eliminating the time-consuming optical focusing process while maintaining detection accuracy.
Solution Approach 2:
The patent introduces a detection probe as an intermediary device between the camera system and the target probe. This detection probe with its contact member serves as a mediator that converts the optical detection problem into a mechanical measurement problem, enabling faster detection through physical contact and displacement sensing.
2Loss of information
If needle marks are transferred onto a transfer sheet, then XY coordinate data can be acquired, but Z coordinate data of probe tips cannot be detected with high accuracy
Solution Approach 1:
The patent transitions from two-dimensional needle mark detection on a flat transfer sheet to three-dimensional direct contact detection. By using a vertically movable contact member with displacement sensor, the system directly measures the Z-coordinate (height) of probe tips through mechanical contact, adding accurate vertical dimension measurement capability that was missing in the needle mark method.
Solution Approach 2:
Instead of creating indirect copies (needle marks) of probe positions on a transfer sheet, the patent uses a detection probe to directly sense and copy the actual three-dimensional position information of target probes. The displacement sensor captures the real spatial coordinates, providing accurate Z-coordinate data without relying on indirect mark-based methods.
3Measurement precision
If excessive pressure is applied to detect probe tips, then detection can be achieved, but the probe card may be damaged
Solution Approach 1:
The patent incorporates a soft member at the contact interface of the detection probe to cushion the contact force. This soft material absorbs and distributes the pressure, preventing excessive force from being transmitted to the delicate probe tips during detection, thereby protecting the probe card from damage while maintaining detection capability.
Solution Approach 2:
The patent changes the physical parameter of the contact surface by using a soft member instead of a hard contact point. This material parameter change allows the contact interface to deform and adapt to the probe tip geometry, distributing the contact pressure over a larger area and reducing the peak stress that could damage the probe card.
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 simplifies the detection process, enabling high-accuracy alignment of inspection electrodes and probes within a shorter time, increasing inspection reliability and reducing the risk of probe card damage.
Implementation Method 1
a first imaging unit movably arranged above the mounting table to capture an image of the object
Implementation Method 2
a second imaging unit mounted to the mounting table to capture an image of the probes
Implementation Method 3
transferring needle marks of the probes onto a soft member provided at the tip position detecting device by allowing the probes to come into contact with the soft member
Data Source
AI summary
An alignment method is used in implementation of electric characteristic inspection of an object to be inspected via electric contact between the object disposed on a movable mounting table and probes. The alignment method includes detecting tip positions of the probes by using the tip position detecting device, detecting the tip positions of the probes, previously detected by the tip position detecting device, by using the second imaging unit, transferring needle marks of the probes onto a soft member provided at the tip position detecting device by allowing the probes to come into contact with the soft member, detecting the needle marks of the probes formed on the soft member by using the first imaging unit, and detecting inspection electrodes of the object corresponding to the probes by using the first imaging unit.