Piezoelectric Contact Load Sensor for Semiconductor Wafer Inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing contact load measuring apparatuses face challenges in accurately measuring contact load between a probe and a semiconductor wafer during electrical property inspection due to sensor deformation and tilt, leading to measurement errors.
Innovation Solution
A contact load measuring apparatus using a compression-type piezoelectric element as a load sensor, which detects contact load as an oscillation waveform and is preloaded to minimize deformation, combined with an antiphase signal generator to dampen vibrations and stabilize the mounting table, ensuring high accuracy and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a load sensor is used to measure contact load, then measurement capability is provided, but sensor deformation occurs causing measurement errors
Solution Approach 1:
A rigid beam structure is introduced as an intermediary between the mounting table and the load sensor. The beam transmits the contact load to the sensor while its high rigidity prevents deformation, ensuring accurate measurement without the sensor itself deforming under load
2Productivity
If the mounting table is moved up by a specific overdriving amount, then contact load is applied, but the mounting table may be tilted or sunk down
Solution Approach 1:
The rigid beam acts as a mediator between the mounting table and probe card, providing a stable load transmission path that prevents table tilt and sinking while allowing the necessary overdriving motion for contact load application
3Reliability
If the contact load is increased to ensure probe-wafer contact, then contact reliability improves, but the probe card may be bent or mounting table sunk
Solution Approach 1:
The patent replaces direct mechanical contact between the mounting table and probe card with a controlled load application system using the rigid beam and load sensor, allowing precise contact load application without excessive force that could damage components
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
Enables direct, high-accuracy measurement of contact load without affecting the inspection process, stabilizing the mounting table quickly and increasing inspection throughput by suppressing sensor deformation and vibration.
Implementation Method 1
a load sensor that detects the contact load, the load sensor including a compression-type piezoelectric element
Implementation Method 2
which detects contact load as an oscillation waveform and is preloaded to minimize deformation
Data Source
AI summary
An inspecting apparatus is provided for inspecting electrical characteristics of an object (W) to be inspected, such as a semiconductor wafer. The inspecting apparatus is provided with a placing table (11) for supporting the object, a lift mechanism (12) for bringing up and down the placing table, and a driving apparatus (24) for driving the lift mechanism. The apparatus is also provided with a probe (13A) which makes contact with the object on the placing table brought up by the lift mechanism driven by the driving apparatus, and a load sensor (21), including a compression-type piezoelectric element, for detecting a contact load between the object and the probe as an oscillation waveform.