Flexible PCB Screen Printing Sintering Process
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Solution Overview
Problem
The manufacturing of flexible printed circuit boards is complex and costly due to etching or plating processes, which also lead to issues like circuit pattern delamination and high heat generation, affecting the reliability and productivity of the final product.
Innovation Solution
A flexible printed circuit board is manufactured using a screen printing technique with conductive paste on a substrate, sintered at 290° C. to 420° C., eliminating the need for plating and optimizing the resistivity and bond strength of the circuit pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If etching or plating processes are used to form circuit patterns, then the circuit pattern can be formed on the substrate, but the manufacturing process becomes complex and production cost increases
Solution Approach 1:
The patent extracts and eliminates the complex etching and plating processes from the manufacturing flow, retaining only the essential screen printing step to form circuit patterns. This simplifies the manufacturing process while maintaining circuit pattern formation capability through direct printing of conductive paste followed by low-temperature sintering
Solution Approach 2:
The patent replaces the mechanical/chemical etching and plating systems with a printing-based system. Instead of using etchants to remove material and plating solutions to deposit metal, the invention uses screen printing to directly deposit conductive paste that is then sintered to form functional circuit patterns
2Manufacturing precision
If etching or plating processes are used to form circuit patterns, then the circuit pattern can be formed on the substrate, but production cost increases
Solution Approach 1:
The patent employs screen printing technology which uses inexpensive conductive paste formulations and simple screen printing equipment compared to expensive plating lines. The screen printing screens are disposable or easily replaceable, reducing equipment investment and maintenance costs while achieving the required circuit pattern precision
Solution Approach 2:
The patent changes the manufacturing parameters from high-cost etching/plating conditions to low-cost printing parameters. By using screen printing with controlled paste composition and low-temperature sintering (290-420°C), the process achieves circuit pattern formation at lower material and equipment costs
3Manufacturing precision
If plating process is used to form circuit pattern, then the circuit pattern can be formed, but circuit pattern delamination occurs affecting reliability
Solution Approach 1:
The patent extracts the plating process from the manufacturing sequence, eliminating the root cause of delamination. By using direct screen printing and sintering of conductive paste, the invention removes the intermediate plating layer that is prone to delamination, creating a more reliable bond between the circuit pattern and substrate
Solution Approach 2:
The patent uses composite conductive paste formulations containing metal particles, glass flakes, and organic vehicles that, when sintered, create a composite circuit pattern with strong adhesion to the substrate. This composite structure provides both electrical conductivity and mechanical bonding strength, eliminating delamination issues
4Manufacturing precision
If conventional manufacturing processes are used, then circuit patterns can be formed, but heat generation affects productivity and reliability
Solution Approach 1:
The patent changes the sintering temperature parameter from conventional high-temperature processes to low-temperature sintering (290-420°C). This parameter change reduces heat generation during manufacturing, improving productivity by shortening cycle time and enhancing reliability by preventing heat-related defects while still achieving proper circuit pattern formation
Solution Approach 2:
The patent utilizes phase transition of the organic vehicle in the conductive paste during low-temperature sintering. The organic binder undergoes decomposition and phase change at relatively low temperatures, enabling the metal particles to sinter and form conductive pathways without requiring high temperatures that would generate excessive heat
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 simplifies the production process, reduces costs, and enhances the reliability of the flexible printed circuit boards by maintaining excellent bond strength and resistivity standards without the need for plating, thus improving productivity and avoiding heat-related issues.
Implementation Method 1
the conductive paste being sintered at 290° C. ̃420° C.
Data Source
AI summary
The present invention relates to a method for manufacturing a flexible printed circuit board and a flexible printed circuit board manufactured by using the same. A circuit pattern is formed with a conductive paste on one surface of a base material, and the circuit pattern is sintered at a temperature of 290° C. to 420° C. to manufacture the flexible printed circuit board. As such, manufacturing costs can be reduced and productivity can be improved through a simple yet convenient process. Also, the circuit pattern is formed without a plating process, such that the problem of circuit pattern separation occurring during the plating process can be addressed and product reliability can be improved.