Wiring Board Lamination Using Viscoelastic Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for manufacturing wiring boards using thermotropic liquid crystal polymer films often result in non-uniform quality due to insufficient control over the hot pressing temperature, leading to high frequencies of imperfect products, as the transformation from a solid to a liquid state is not uniform across different polymer lots.
Innovation Solution
A method is developed where the viscoelastic characteristics of the thermotropic liquid crystal polymer film are measured at a low frequency within a laminating temperature range, and hot pressing is carried out at a selected temperature within a predetermined range (240 to 350°C) to ensure uniform quality, with apparent melt viscosity measured between 1×10^4 to 2×10^5 Pa-s, and the thermotropic liquid crystal polymer film is adjusted to have a segment orientation ratio between 1.00 to 1.15.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot pressing temperature is determined on the basis of melting point, then productivity is improved, but manufacturing precision deteriorates due to non-uniform quality across different polymer lots
Solution Approach 1:
The patent changes the control parameter from melting point to viscoelastic characteristic value. By measuring and controlling the viscoelastic characteristic value at a low frequency within the laminating temperature region, the hot pressing temperature can be precisely adjusted to ensure uniform quality across different polymer lots while maintaining high productivity.
Solution Approach 2:
The patent introduces a feedback mechanism where the viscoelastic characteristic value is measured and used to determine the appropriate hot pressing temperature. This closed-loop control ensures that temperature settings are adjusted based on actual material properties, preventing quality variation while maintaining efficient production.
2Manufacturing precision
If hot pressing temperature is selected to ensure uniform quality, then manufacturing precision is improved, but productivity decreases due to additional measurement and adjustment steps
Solution Approach 1:
The patent performs preliminary measurement of the viscoelastic characteristic value before hot pressing. This advance characterization allows for optimal temperature determination without adding significant time to the production process, as the measurement can be performed on material batches before they enter the main production line.
Solution Approach 2:
The material itself provides the control information through its viscoelastic characteristic value. By measuring this intrinsic property, the system uses the material's own characteristics to determine processing parameters, eliminating the need for external complex testing or quality control steps.
3Reliability
If thermotropic liquid crystal polymer is used for wiring boards, then reliability is improved through low hygroscopic property and heat resistance, but manufacturing precision deteriorates due to non-uniform transformation from solid to liquid state
Solution Approach 1:
The patent changes the control approach from using melting point to using viscoelastic characteristic value. This parameter change allows for precise control of the laminating process, ensuring uniform transformation from solid to liquid state while maintaining the inherent reliability benefits of thermotropic liquid crystal polymer.
Solution Approach 2:
The patent replaces the conventional thermal control mechanism (based on melting point) with a viscoelasticity-based control mechanism. By measuring and controlling the viscoelastic characteristic value, the process achieves more uniform material transformation and better manufacturing precision while preserving the material's reliability properties.
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 the production of wiring boards of uniform quality at a high yield, with improved heat resistance, chemical resistance, and electrical properties, while maintaining the low hygroscopic properties of the thermotropic liquid crystal polymer.
Implementation Method 1
the transformation from a solid to a liquid state is not uniform across different polymer lots
Implementation Method 2
the viscoelastic characteristic value of the thermotropic liquid crystal polymer forming the film referred to above is measured at a low frequency within a laminating temperature region
Data Source
AI summary
The object of the invention is to provide a wiring board having the uniform quality at a high yield which is produced by hot-pressing and laminating on a wiring board base material a thermotropic liquid crystal polymer which is excellent as a wiring board covering material.The present invention provides a method of making a wiring board comprising: hot-pressing and laminating a thermotropic liquid crystal polymer film on a wiring board base material on the surface of which at least one layer containing a electro-conductive circuit is exposed, characterized by that a viscoelastic characteristic of the thermotropic liquid crystal polymer film is measured at a low frequency within a laminating temperature region and the hot-pressing is carried out at a temperature selected so that the viscoelastic characteristic falls within a predetermined range.