Embedded Signal Planes in Disk Drive Head Suspensions
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Solution Overview
Problem
Current disk drive head suspensions face challenges in accommodating increasing numbers of signal conducting traces with high bandwidth and low impedance, while maintaining efficient manufacturing and physical size constraints.
Innovation Solution
A head suspension flexure with a metal base layer, insulation layer, and embedded signal transmission structures, including conductive metal planes and connection vias, to enhance signal carrying capabilities and reduce impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of signal conducting traces is increased to accommodate complex read/write heads and IC chips, then the signal carrying capacity is improved, but the impedance increases and bandwidth decreases
Solution Approach 1:
The patent transitions from two-dimensional trace routing on the suspension surface to three-dimensional embedded signal transmission structures. Conductive planes are embedded within the suspension substrate at different depths, creating vertical stacking of signal paths. This dimensional change allows multiple high-capacity signal channels to coexist without increasing lateral trace density, thereby maintaining low impedance and high bandwidth while accommodating increased signal requirements.
Solution Approach 2:
The suspension structure employs composite material construction with multiple layers including conductive metal planes, insulating materials, and structural substrates. The embedded signal transmission structures combine conductive layers with dielectric materials to create shielded signal paths. This composite approach provides both electrical performance (low impedance, high bandwidth) and mechanical integrity, resolving the contradiction between signal capacity and signal quality.
2Area of stationary object
If the physical size of the suspension is decreased to maintain compact disk drive design, then the area is reduced, but the ability to accommodate sufficient traces with adequate signal performance deteriorates
Solution Approach 1:
The patent implements nested signal transmission structures where conductive planes are embedded within the suspension substrate at multiple depth levels. Signal paths are nested vertically rather than laterally, allowing multiple high-capacity traces to occupy the same horizontal footprint. This nesting approach enables compact suspension design while maintaining sufficient signal carrying capacity through three-dimensional space utilization.
Solution Approach 2:
By moving signal transmission from the two-dimensional surface plane to the three-dimensional interior volume of the suspension, the patent achieves higher signal capacity within reduced lateral dimensions. The embedded conductive planes utilize the vertical dimension for signal routing, effectively increasing trace density without increasing the suspension's planar footprint.
3Ease of manufacture
If traditional trace routing is used to accommodate more signals, then the manufacturing process remains simple, but the signal impedance increases and bandwidth decreases
Solution Approach 1:
The embedded signal transmission structures are incorporated into the suspension manufacturing process during the substrate formation stage, before final assembly. Conductive planes are embedded within the suspension substrate using standard semiconductor fabrication techniques such as sputtering, evaporation, or electroplating. This preliminary integration of signal structures into the base manufacturing process avoids complex post-assembly trace routing operations, maintaining manufacturing efficiency while achieving superior electrical performance.
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
The solution effectively increases signal carrying capacity, reduces impedance, and minimizes cross-talk, while being efficient to manufacture, thus addressing the need for improved mechanical and electrical performance in disk drive technology.
Implementation Method 1
connection vias through the insulation layer coupling the terminals and the metal planes
Data Source
AI summary
A disk drive head suspension flexure having a gimbal region and a tail includes a metal base layer, an insulation layer over the base layer and two or more pairs of adjacent traces extending over the insulation layer from the gimbal region to the tail. Each trace includes terminals on the gimbal region and tail. Two or more conductive metal signal transmission planes are embedded within the insulation layer and extend from the gimbal region to the tail between the pairs of traces and metal base layer. Each of the embedded signal transmission planes has a width extending across a width of a pair of the traces. Terminals on the gimbal region and tail are coupled to the signal transmission planes by connection vias extending through the insulation layer.