Package Circuit Pad Inspection Using Liquid Crystal Rotation
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Solution Overview
Problem
The manufacturing yield and quality of package circuits in electronic devices are not adequately addressed by existing methods, necessitating improved inspection techniques to ensure conductivity and prevent defects.
Innovation Solution
A manufacturing method involving the formation of a liquid crystal layer on a circuit structure, where conductivity of conductive pads is determined by observing the rotation of liquid crystal molecules under an electric field, followed by a non-contact inspection and subsequent removal of the liquid crystal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional contact-based inspection methods are used to test conductivity of conductive pads, then inspection can be performed, but the conductive pads are at risk of damage and manufacturing yield decreases
Solution Approach 1:
The patent replaces mechanical contact-based conductivity testing with a non-contact optical inspection method. Liquid crystal molecules are used as sensors that respond to electric fields generated by conductive pads, and their orientation is detected optically through a microscope, eliminating mechanical contact and associated damage risks
Solution Approach 2:
The patent introduces liquid crystal molecules as an intermediary medium between the conductive pads and the detection system. These molecules serve as transducers that convert electrical field information into optical orientation changes, enabling indirect non-contact measurement of conductivity
2Reliability
If non-contact optical inspection is used to avoid damage to conductive pads, then pad integrity is maintained, but the precision of conductivity measurement may be insufficient
Solution Approach 1:
The patent utilizes optical anisotropy and birefringence effects in liquid crystal molecules, which cause changes in light polarization and intensity based on molecular orientation. These optical property changes provide precise, measurable signals that correlate with the strength of electric fields from conductive pads
Solution Approach 2:
The patent changes the physical state and orientation parameters of liquid crystal molecules in response to electric fields. By measuring these parameter changes through optical detection, the system achieves precise conductivity measurement without mechanical contact
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 method reduces the risk of damage to conductive pads during inspection, enhances the accuracy of conductivity testing, and improves the manufacturing yield and quality of package circuits by identifying and preventing defective connections.
Implementation Method 1
determining conductivity of the plurality of conductive pads according to a result of the rotation of the liquid crystal layer oriented with an electric field
Data Source
AI summary
The embodiments of the disclosure provide a manufacturing method of a package circuit, including the following steps. A circuit structure including a plurality of conductive pads is formed. A liquid crystal layer is formed on the circuit structure. An inspection step is performed, and the inspection step includes determining the conductivity of the conductive pads according to the result of the rotation of a liquid crystal layer oriented with an electric field. In addition, the liquid crystal layer is removed.