Triangular Lattice Land Group for Printed Wiring Board Terminal Density
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Solution Overview
Problem
The existing methods for increasing terminal density on semiconductor devices while maintaining adequate intervals between terminals on printed wiring boards restrict the design freedom and reduce the number of leading wires, leading to larger apparatus sizes and potential reliability issues.
Innovation Solution
A printed wiring board and semiconductor device with a land and terminal group arranged in a triangular lattice pattern, where the smallest angle between the rectangular region and the triangular lattice sides is between 7° and 23°, allowing for improved terminal density and reduced differences in leading wire numbers between directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If terminals are arranged in a square pattern with parallel sides to the rectangular region, then terminal density is maintained, but the difference in wiring density between leading directions increases and design freedom is restricted
Solution Approach 1:
The patent applies asymmetry by rotating the triangular lattice of terminals at a specific angle (7° to 23°) relative to the rectangular region boundaries. This asymmetric arrangement breaks the symmetry of conventional square or axis-aligned triangular patterns, thereby balancing the wiring density distribution in different leading directions and increasing design freedom while maintaining terminal density.
Solution Approach 2:
The patent transitions from conventional two-dimensional square or axis-aligned triangular arrangements to a rotated triangular lattice arrangement. By introducing a rotational dimension (角度维度) to the terminal layout, the patent optimizes the spatial distribution of terminals and leading wires, achieving balanced wiring density in multiple directions simultaneously.
2Quantity of substance
If terminals are arranged with short intervals to increase terminal density, then more terminals per unit area are achieved, but mounting reliability is lowered
Solution Approach 1:
The patent changes the geometric parameters of terminal arrangement by adopting a triangular lattice pattern with specific rotation angles (7° to 23°). This parameter optimization allows achieving higher terminal density while maintaining adequate intervals between adjacent terminals, thus preserving mounting reliability. The specific angle range is determined to balance terminal density and interval requirements.
3Quantity of substance
If the area of the wiring substrate is expanded to increase terminal count, then more terminals are available, but the cost and apparatus size increase
Solution Approach 1:
The patent optimizes the spatial parameters of terminal arrangement using a rotated triangular lattice pattern. This optimized arrangement increases terminal density (terminals per unit area), allowing more terminals to be accommodated on the same wiring substrate area, thereby avoiding increases in apparatus size and cost while achieving higher terminal counts.
4Quantity of substance
If terminals are arranged in a triangular lattice with sides parallel to the rectangular region, then terminal density is increased, but the difference in leading wire numbers between directions increases
Solution Approach 1:
The patent applies asymmetry by rotating the triangular lattice at a specific angle (7° to 23°) relative to the rectangular region boundaries. This asymmetric arrangement balances the distribution of leading wires in different directions, reducing the difference in leading wire numbers between opposite directions, while maintaining high terminal density.
Data Source
AI summary
A printed wiring board includes conductive layers laminated with insulator layers interposed. A land group including a plurality of lands arranged with intervals between each other, is formed in a rectangular region on a surface layer, among the plurality of conductive layers, when viewed in a direction perpendicular to the surface layer. The land group is arrayed in a triangular lattice manner. The land group is arranged so that a smallest angle, among angles formed between one side of the rectangular region and respective three sides of the triangular lattice, is 7° or more and 23° or less.