Wiring Board Chamfered Through-Hole via Laser Burr Removal
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Solution Overview
Problem
The high manufacturing cost of wiring boards with through-hole wirings is due to the complex process of forming openings in copper foils, which involves photosensitive resist layers and etching, leading to increased costs and potential disconnections in the wiring layers.
Innovation Solution
A method of manufacturing a wiring board that involves forming through-holes in a core layer with laser processing and removing burrs to create chamfered portions, allowing for the formation of metal layers that cover and fill the holes, reducing the need for complex resist layer formation and etching processes, and enhancing adhesion between the core layer and wiring patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If openings are formed through copper foils by etching with photosensitive resist layers, then through-hole wirings can be formed, but the manufacturing process becomes complicated and manufacturing cost increases
Solution Approach 1:
The invention extracts and removes the copper foil from the regions where through-holes are to be formed, rather than using photosensitive resist layers and etching. This is achieved by forming openings through the copper foil using a simpler method that eliminates the need for complex resist layer formation, exposure, and development processes, thereby reducing manufacturing complexity while maintaining connection reliability
Solution Approach 2:
Instead of forming openings by protecting areas with resist layers and etching away exposed copper, the invention inverts the approach by directly removing copper in desired opening regions without using photosensitive resist layers. This reversal of the conventional process simplifies the manufacturing steps and reduces costs
2Reliability
If openings are formed through copper foils by etching, then through-hole wirings can be formed, but manufacturing cost increases
Solution Approach 1:
The invention extracts and removes the copper foil from the regions where through-holes are to be formed, rather than using photosensitive resist layers and etching. This is achieved by forming openings through the copper foil using a simpler method that eliminates the need for complex resist layer formation, exposure, and development processes, thereby reducing manufacturing complexity and cost while maintaining connection reliability
Solution Approach 2:
The invention replaces expensive and complex photosensitive resist layers with a simpler, more cost-effective method for forming openings. By eliminating the need for resist materials, exposure equipment, and development processes, the manufacturing cost is significantly reduced while achieving the same functional result of creating through-holes for wiring
3Manufacturing precision
If burrs are present at the through-hole opening, then metal layer formation is compromised, but removing burrs is not performed in conventional processes
Solution Approach 1:
The invention performs preliminary action by removing burrs from the through-hole openings before forming the metal layer. This preliminary burr removal ensures that the subsequent metal layer formation process is not compromised, allowing for high-quality plating without defects. By addressing the burr issue beforehand, the process ensures proper adhesion and uniform thickness of the metal layer
4Reliability
If plating liquid supply is insufficient within through-holes, then voids and disconnections occur, but conventional processes do not address this issue
Solution Approach 1:
The invention performs preliminary action by removing burrs from the through-hole openings before forming the metal layer. This preliminary burr removal ensures that the subsequent metal layer formation process is not compromised, allowing for high-quality plating without defects. By addressing the burr issue beforehand, the process ensures proper adhesion and uniform thickness of the metal layer
Solution Approach 2:
The invention converts the potential harm of burrs (which can block plating liquid supply) into a benefit by systematically removing them. The burr removal process, while adding a step, prevents the formation of voids and disconnections, thereby improving overall plating quality and wiring reliability. The harmful effect of burrs is transformed into an opportunity to ensure proper plating liquid penetration
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 reduces manufacturing costs and increases the reliability of the wiring board by ensuring sufficient plating liquid supply within the through-holes, minimizing voids and disconnections, and improving the connection reliability between the core layer and wiring layers.
Implementation Method 1
laser processing is performed on the exposed portions of the respective surfaces of the insulating layer through the openings, thereby forming through-holes
Implementation Method 2
the through-holes are filled with the plating material
Data Source
AI summary
A wiring board includes a core layer, a through-hole penetrating through the core layer in its thickness direction, a first wiring layer formed on a first surface of the core layer, a through-hole wiring formed in the through-hole and electrically connected to the first wiring layer, and a curved first chamfered portion formed in a boundary portion between an inner side surface of the through-hole and the first surface of the core layer. The first wiring layer includes a first metal layer formed outside the first chamfered portion on the first surface of the core layer and a second metal layer formed on the first chamfered portion and the first metal layer.