Probe Tip Height Detection Using Load Sensor Contact

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Solution Overview

Problem

Existing methods for detecting probe tip height and alignment in semiconductor wafer inspection are inadequate, particularly when dealing with various types of probe cards, as they rely on optical alignment methods that struggle with different materials and shapes, and do not effectively detect the height of probe tips before alignment.

Innovation Solution

A method using a movable mounting table with a first and second imaging unit, where the height of a load sensor is detected, and the mounting table moves to contact the probe tips, allowing for precise detection of probe tip height without relying on optical units, and confirming the load sensor's operation using a pin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If optical alignment method using camera is used to detect probe tips, then alignment can be performed, but detection becomes difficult when probe materials or shapes vary

Engineering Contradiction:

Improvecompatibility with various probe card typesVSAvoidprobe tip detection difficulty

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

A load sensor is introduced as an intermediary object to detect probe tip height. Instead of directly imaging the probe tips with a camera, the system uses the load sensor's contact with the probe tips to generate detectable signals, thereby resolving the detection difficulty caused by varying probe materials and shapes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The optical detection system is replaced with a mechanical contact-based detection system. The load sensor physically contacts the probe tips to measure their height, substituting the optical imaging method with a mechanical measurement approach that is independent of probe material and shape characteristics.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If laser measuring device is used to detect probe tip height, then precise height detection is achieved, but the method does not detect probe tip height before alignment

Engineering Contradiction:

Improveprobe tip height precisionVSAvoidalignment process timing

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The load sensor detection is performed before the alignment process to pre-acquire probe tip height information. This preliminary measurement allows the system to prepare alignment parameters in advance, eliminating the need for time-consuming post-alignment adjustments and ensuring precise height detection is available when needed.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If pressure sensor on wafer chuck is used to set specific contact pressure, then reliable electrical contact is achieved, but probe tip height cannot be detected upon alignment

Engineering Contradiction:

Improveelectrical contact reliabilityVSAvoidprobe tip height detection

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The load sensor serves as an intermediary measurement device that independently detects probe tip height without interfering with the contact pressure control function of the wafer chuck pressure sensor. This separate measurement path enables both functions to operate simultaneously without compromising either reliability or measurement precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Measurement precision

If mounting table is moved to make probes contact load sensor, then probe tip height is detected based on moving amount, but precise positioning is required

Engineering Contradiction:

Improveprobe tip height detection accuracyVSAvoidmounting table positioning precision

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The system uses feedback from the load sensor to verify and refine the mounting table positioning. As the mounting table moves to bring the probes into contact with the load sensor, the load sensor provides real-time feedback on the contact status, allowing the control system to make precise adjustments and confirm accurate positioning based on the measured moving distance.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7800387B2Method for detecting tips of probes, alignment method and storage medium storing the methods, and probe apparatus

Publication Date: 2010.09.21 TOKYO ELECTRON LTD

AI summary

There is provided a method for detecting a height of a tip of a probe before detecting a horizontal position of the probe tips of the probe, by using an alignment device having a first imaging unit and a second imaging unit provided at the mounting table. In the method, at a first step, a height of a load sensor provided in the mounting table is detected by using the first imaging unit. Further, at a second step, the mounting table is moved to make the probe come in contact with the load sensor and a height of the probe tip is detected based on a moving amount of the mounting table. In addition, it is confirmed whether the load sensor operates normally by using a pin, between the first and the second step.