PCB Blind Via Laser Activation Catalyst
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Solution Overview
Problem
The existing methods for manufacturing printed circuit boards face challenges in achieving high density distribution of blind vias and metal bumps due to the need for larger openings in the dielectric and photoresist layers, which reduces productivity and increases complexity in alignment processes.
Innovation Solution
A method involving a laser-activated catalyst in the dielectric ink, allowing for precise definition of blind vias and subsequent electro-less copper plating, eliminating the need for larger openings and improving alignment, resulting in higher productivity and increased density of blind vias and metal bumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the second opening is larger than the first openings to achieve alignment, then the alignment is easier, but the distribution density of the second openings and traces is smaller
Solution Approach 1:
The patent replaces the mechanical alignment process (manual or automated alignment of photoresist pattern with laser openings) with a direct laser writing process. The laser directly writes the openings in the dielectric layer without requiring a separate photoresist alignment step, thereby eliminating the need for larger second openings and enabling higher distribution density while maintaining manufacturing ease
Solution Approach 2:
The patent changes the size parameter of the openings by eliminating the alignment buffer margin. Since the laser direct writing process inherently provides precise positioning, the openings can be made smaller and closer together while still achieving proper alignment, thus increasing the distribution density from the conventional larger openings
2Manufacturing precision
If multiple developing processes are used to form openings in dielectric and photoresist layers, then the alignment can be achieved, but the manufacturing complexity and time increase
Solution Approach 1:
The patent merges multiple separate processes (laser opening formation in dielectric layer, photoresist coating, photoresist exposure and development) into a single integrated process. The laser directly writes the openings through the dielectric layer without requiring a separate photoresist layer, thereby reducing process complexity while maintaining alignment precision
Solution Approach 2:
The patent extracts and removes the photoresist layer from the manufacturing process. By using laser direct writing to form openings directly in the dielectric layer, the photoresist coating, exposure, and development steps are completely eliminated, simplifying the overall process while preserving alignment capability
3Ease of manufacture
If larger openings are used in dielectric and photoresist layers, then the alignment is easier to achieve, but the productivity and distribution density are reduced
Solution Approach 1:
The patent replaces the mechanical alignment system with laser direct writing technology. The laser system inherently provides precise positioning and writing capability, eliminating the need for larger openings as alignment buffers. This enables smaller, denser openings to be written directly, increasing productivity and distribution density while maintaining alignment ease through the laser's inherent precision
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 a higher density of blind vias and metal bumps, enhancing the manufacturing efficiency and productivity by eliminating the need for multiple developing processes and improving electrical connectivity.
Implementation Method 1
a laser-activated catalyst in the dielectric ink
Implementation Method 2
laser-activated catalyst in the dielectric ink, allowing for precise definition of blind vias and subsequent electro-less copper plating
Implementation Method 3
subsequent electro-less copper plating, eliminating the need for larger openings and improving alignment
Data Source
AI summary
A printed circuit board includes a base, a number of conductive pads, a dielectric layer, an activated metal layer, a first metal seed layer, a second metal seed layer, and a plurality of metal bumps. The conductive pads are formed on the base. The dielectric layer is formed on a surface of the conductive pads and portions of the base are exposed from the conductive pads. The dielectric layer includes blind vias corresponding to the conductive pads, and a laser-activated catalyst. The activated metal layer is obtained by laser irradiation at the wall of the blind via. The activated metal layer is in contact with the dielectric layer. The second metal seed layer is formed on the activated metal layer and the conductive pads. Each metal bump is formed on the second metal seed layer, and each metal bump protrudes from the dielectric layer.