Embedded PCB Conductor Structures via Laser Plasma Etching
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Solution Overview
Problem
Traditional methods for producing printed circuit boards, especially multilayer boards, face challenges such as limited resolution of conductor structures, high production complexity, and increased costs due to the surface placement of conductor tracks, which requires extensive monitoring and correction during assembly and results in yield losses.
Innovation Solution
A method involving a base substrate with a cover metal layer, where plasma etching is used to create trenches and fill them with metal, allowing for the formation of conductor structures that are embedded within the substrate, reducing the need for surface-level conductor tracks and enabling higher resolution with lower complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional subtractive photolithographic processes are used to form conductor tracks, then the process is relatively simple and cost-effective, but the resolution is limited and conductor track widths in the low two-digit or one-digit μm range cannot be produced
Solution Approach 1:
The patent replaces the traditional photolithographic mechanical/chemical process with a direct laser writing process. The laser beam directly writes conductor tracks by locally modifying the base substrate material, eliminating the need for photoresist coating, exposure, development, and etching steps. This substitution enables sub-micrometer resolution while maintaining process simplicity and reducing the number of manufacturing steps.
Solution Approach 2:
The patent changes the fundamental parameter of how conductor tracks are formed - instead of using chemical reactions and material removal through multiple stages, it uses direct energy deposition from a laser to locally melt, vaporize, or sinter the base substrate material. This parameter change enables precise control of conductor track dimensions at sub-micrometer scale while simplifying the overall process.
2Reliability
If conductor tracks are placed on the surface of the base substrate, then the production process is simpler, but extensive monitoring and correction are needed during assembly due to deviations caused by pressing pressures and temperatures
Solution Approach 1:
The patent transitions conductor tracks from a two-dimensional surface placement to a three-dimensional embedded structure within the base substrate. By forming conductor tracks inside the substrate material through laser writing, the design is protected from surface-level mechanical stresses and thermal deformations during assembly pressing, thereby improving reliability without requiring additional monitoring and correction steps.
Solution Approach 2:
The patent performs the conductor track formation and embedding within the base substrate before the assembly pressing process. This preliminary action ensures that the conductor tracks are already protected and fixed in their precise positions before any pressing or thermal processing occurs, eliminating the need for subsequent monitoring and correction during assembly.
3Manufacturing precision
If additive and semi-additive approaches are used to form conductor tracks, then higher resolution is achieved, but enormous technical complexity is introduced resulting in yield losses and high production costs
Solution Approach 1:
The patent replaces complex additive manufacturing systems (which require multiple deposition, patterning, and planarization steps) with a direct laser writing system. The laser beam directly creates conductor tracks by modifying the base substrate material in situ, eliminating the need for separate metal deposition equipment, photoresist processing, and multiple alignment steps, thereby achieving high resolution with simplified process equipment.
Solution Approach 2:
The patent merges the conductor track formation process with the base substrate processing into a single step. The laser writing process simultaneously creates the conductor pattern and defines its position within the base substrate, combining what would traditionally require separate patterning and deposition steps into one integrated process, thereby reducing overall process complexity.
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 enables the production of printed circuit boards with high resolution in the μm range, reducing production complexity and costs while improving yield, and minimizing the impact of assembly pressures on conductor structures, thus addressing the limitations of traditional subtractive and additive processes.
Implementation Method 1
causing a plasma to act on the first substrate side with the aid of which plasma the polymer material is removed in the at least one first partial area while forming at least one trench
Data Source
AI summary
A method of producing a multilayer printed circuit board includes a metallic conductor structure including providing a base substrate including a film or plate and having first and second substrate sides, which base substrate at least partly consists of an electrically non-conductive organic polymer material and wherein the first substrate side is covered with a cover metal layer, partially removing the cover metal layer while subdividing the first substrate side into at least one first partial area, in which the first substrate side is free of the cover metal layer, and into at least one second partial area, in which the first substrate side is covered with the cover metal layer, and causing a plasma to act on the first substrate side with the aid of which plasma the polymer material is removed in the at least one first partial area while forming at least one trench.