Reduced PTH Pad for Core Routing Density
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Solution Overview
Problem
The increasing density and complexity of semiconductor devices pose challenges in maintaining the minimum dielectric spacing between hole walls and conductive features, risking electromagnetic interference and requiring larger anti-pads to prevent shorting, which complicates PCB design and increases package size.
Innovation Solution
The use of laser drilling to create smaller plated through holes (PTHs) and reduced pad sizes, enabling finer traces and smaller anti-pads, allowing for more efficient routing and reducing the substrate layer count through semi-additive processes and semi-subtractive processes with copper foils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional mechanical drilling is used to create PTHs, then the manufacturing process is simpler and more established, but the PTH size and pad size must be larger to maintain adequate dielectric spacing
Solution Approach 1:
The patent replaces traditional mechanical drilling with laser drilling to create plated through holes. This substitution enables precise control of PTH dimensions and positioning without the tolerance limitations of mechanical processes, allowing for smaller pads and tighter spacing while maintaining manufacturing feasibility through a different physical mechanism.
Solution Approach 2:
The patent changes the drilling method from mechanical to laser-based, fundamentally altering the process parameters. This enables PTH diameters as small as 0.1mm and positioning precision within 0.05mm, which directly enables reduced pad sizes and increased routing density without compromising structural integrity or electrical performance.
2Reliability
If larger anti-pads are used to prevent shorting and maintain dielectric spacing, then manufacturing reliability improves, but package size increases and routing density decreases
Solution Approach 1:
By replacing mechanical drilling with laser drilling, the patent achieves superior positioning precision and smaller PTH diameters. This allows anti-pads to be reduced in size while maintaining adequate dielectric spacing, thereby preventing shorting without increasing overall package dimensions.
Solution Approach 2:
The patent utilizes laser technology, which involves focused energy delivery similar to pneumatic/hydraulic precision systems. The laser beam provides precise energy concentration to create clean, accurate PTHs with minimal heat-affected zones, enabling tighter spacing and smaller anti-pads while maintaining reliability.
3Area of stationary object
If smaller PTHs and pads are used to increase routing density, then package size reduces, but the risk of violating minimum dielectric spacing specifications increases
Solution Approach 1:
The patent replaces mechanical drilling with laser drilling, achieving positioning precision within 0.05mm and PTH diameter control down to 0.1mm. This precision ensures that even with reduced pad sizes and tighter spacing, the minimum dielectric spacing specifications are consistently maintained, eliminating the reliability risk associated with smaller features.
Solution Approach 2:
By changing from mechanical to laser drilling, the patent achieves parameter control (PTH diameter, positioning accuracy) that enables smaller package dimensions while maintaining dielectric spacing compliance. The laser process provides consistent, repeatable results that ensure reliability specifications are met regardless of the reduced feature sizes.
4Ease of manufacture
If traditional mechanical drilling is used, then manufacturing process is simpler, but routing density and trace fineness are limited
Solution Approach 1:
The patent replaces mechanical drilling with laser drilling, which simplifies the manufacturing process by eliminating tool wear, changing, and alignment issues associated with mechanical drills. The laser process directly creates precise PTHs that enable finer traces and higher routing density, simultaneously improving both ease of manufacture and productivity.
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 allows for a significant reduction in package size, increased routing density, and improved manufacturability by enabling smaller anti-pads and tighter PTH pitches, enhancing the semiconductor package's functionality and reliability while maintaining electromagnetic interference reduction.
Implementation Method 1
The use of laser drilling to create smaller plated through holes (PTHs)
Implementation Method 2
semi-additive processes and semi-subtractive processes with copper foils
Data Source
AI summary
Embodiments are directed to semiconductor packaging having reduced sized plated through hole (PTH) pads by eliminating the margin of the pad-to-PTH alignment and enabling finer traces on the core of the substrate.