Disk Drive Head Suspension Flexure Stacked Traces
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Solution Overview
Problem
Integrated lead head suspension components in hard disk drives face challenges in achieving improved electrical characteristics without compromising mechanical performance, as modifying trace configuration to increase bandwidth or reduce differential impedance negatively impacts gimbal stiffness.
Innovation Solution
An integrated lead head suspension component is designed with a base region and gimbal region, featuring stacked traces with varying widths and dielectric layer thicknesses, manufactured using an additive process to optimize electrical and mechanical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the distance between stacked traces is increased to improve bandwidth, then bandwidth increases, but differential impedance increases and gimbal stiffness increases
Solution Approach 1:
The patent applies different trace widths at different locations along the stacked traces. The traces have a first width in the base region and a second, narrower width in the gimbal region. This local variation in geometry allows the traces to have lower differential impedance where needed (in the gimbal region) while maintaining adequate bandwidth, resolving the contradiction between these two electrical characteristics.
2Object-affected harmful factors
If the trace width is increased to reduce differential impedance, then differential impedance decreases, but gimbal stiffness increases
Solution Approach 1:
The stacked traces are designed with varying widths along their length, being narrower in the gimbal region compared to the base region. This local reduction in trace width in the gimbal area decreases the stiffness contribution of the traces to the gimbal assembly, allowing the gimbal to maintain its intended compliance while the overall trace structure maintains adequate electrical performance.
3Area of stationary object
If the area available for routing traces is reduced due to smaller head suspensions, then device size decreases, but signal transmission performance deteriorates
Solution Approach 1:
The patent employs a stacked trace configuration where multiple conductor layers are separated by dielectric layers, utilizing the vertical dimension to route multiple signals. This three-dimensional trace arrangement allows adequate signal transmission performance to be achieved even when the planar area available for trace routing is reduced due to smaller head suspension sizes.
Data Source
AI summary
An integrated lead head suspension component comprising a spring metal layer, a first conductor layer, a first dielectric layer between at least portions of the spring metal and the first conductor layers, a second conductor layer and a second dielectric layer between at least portions of the first and second conductor layers. The head suspension component includes stacked traces having first and second traces in the first and second conductor layers, respectively. The stacked traces comprise base sections having first widths and gimbal sections having second widths that are less than the first widths. The second dielectric layer can have a generally constant thickness on the base and gimbal sections or, alternatively, a gimbal section thickness that is less than a base section thickness.