Alternating Width Stacked Leads for Disk Drive Flexures
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Solution Overview
Problem
Existing disk drive head suspensions face impedance variations due to trace-to-trace alignment issues in stacked trace configurations, leading to reduced electrical performance, which is exacerbated by manufacturing process variations.
Innovation Solution
An integrated lead flexure with alternating width stacked traces is designed to improve impedance characteristics by ensuring regular alternating wider and narrower portions in the transmission line array, reducing sensitivity to misregistration and maintaining constant phase and group delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stacked trace configurations are used in integrated lead flexures, then electrical connectivity is achieved, but impedance variations occur due to trace-to-trace alignment issues
Solution Approach 1:
The patent applies asymmetry by making one trace in the stacked configuration wider than the other. This asymmetric width design compensates for potential misalignment between traces, as the wider trace provides a larger effective overlapping area with the adjacent trace, thereby maintaining consistent impedance characteristics even when manufacturing alignment varies.
Solution Approach 2:
The patent changes the geometric parameters of the stacked traces by varying their widths. Specifically, one trace has a greater width than the other, and this width parameter is optimized to compensate for alignment variations. By adjusting this physical parameter, the design achieves more robust impedance control despite manufacturing tolerances.
2Ease of manufacture
If regular stacked traces are used, then manufacturing is simplified, but impedance variations and signal reflections increase
Solution Approach 1:
The asymmetric width design maintains relative manufacturing simplicity while improving impedance consistency. The wider trace is designed to accommodate potential misalignment, effectively creating a tolerance buffer that reduces signal reflections and impedance variations without requiring complex manufacturing processes.
Solution Approach 2:
The patent applies local quality by creating different trace widths at specific locations within the stacked configuration. The wider portion is strategically positioned to compensate for alignment issues at critical interfaces, while other portions maintain standard dimensions. This localized modification optimizes impedance control where it is most needed without complicating the overall manufacturing process.
Data Source
AI summary
An integrated lead flexure for a disk drive head suspension of the type having a plurality of stacked leads disposed on separate layers, the plurality of stacked leads extending between terminal connector pads and head connector pads, comprising stacked lead pairs having opposing and regularly alternating wider and narrower portions, respectively.