Disk Drive Circuit Member Stepped Side Pad Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In disk drive suspensions, the reliability of lateral terminal connections is compromised due to the thinness of conductors, leading to inadequate connection areas and potential electric short-circuits from solder bridges, especially when high-temperature solder contacts the polyimide insulating layer, causing deterioration and inaccurate bent portion formations.
Innovation Solution
A circuit member design featuring a stepped side pad that prevents conductive members like solder from contacting the cover layer, with a thick portion, conductor convex portion, and conductor extending portion, providing a stable connection surface and supporting the electronic component at a predetermined position, while the stepped side pad suppresses the movement of conductive members towards the cover layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If terminals are connected in a lateral direction of the conductors, then connection area is increased, but connection reliability deteriorates due to thinness of conductors
Solution Approach 1:
The invention transitions from lateral connection (2D plane connection) to vertical connection (3D height-direction connection) by forming a protrusion on the pad structure. This allows the terminal to connect to the pad from the vertical direction, achieving sufficient connection area without relying on lateral conductor thickness, thereby resolving the contradiction between connection area and connection reliability.
2Strength
If high-temperature solder is supplied on a pad, then bonding is achieved, but polyimide insulating layer is deteriorated by heat
Solution Approach 1:
The invention introduces a protrusion structure as an intermediary between the solder and the polyimide insulating layer. The protrusion extends vertically from the pad surface, allowing solder to bond to the protrusion tip while the broader base of the protrusion dissipates heat away from the polyimide layer, thus achieving bonding strength without direct heat damage to the insulating layer.
Solution Approach 2:
The protrusion creates a localized bonding region at its tip where solder is concentrated, while the base of the protrusion and surrounding pad area serve as heat dissipation zones. This local concentration of bonding function separates the high-temperature bonding zone from the heat-sensitive polyimide layer, resolving the contradiction between bonding strength and heat damage prevention.
3Productivity
If molten solder is supplied to multiple pads, then all pads are bonded, but solder may adhere to portions between adjacent pads causing electric short-circuit
Solution Approach 1:
The invention segments the bonding interface by creating distinct protrusions on each pad, separated by grooves or recesses. This segmentation confines the molten solder to specific protrusion tips during bonding, preventing solder from spreading to adjacent pads or inter-pad regions, thus maintaining electrical insulation while achieving efficient bonding of multiple pads.
Solution Approach 2:
The protrusion structure acts as an intermediary that confines solder flow during the bonding process. The vertical geometry of the protrusions directs solder upward to the tip regions, preventing lateral spread to adjacent pads, thereby maintaining electrical isolation between circuits while enabling simultaneous bonding of multiple pads.
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 design enhances the reliability and accuracy of connections by preventing solder bridges and ensuring stable, heat-resistant bonding, thereby improving the reliability of terminal connections and preventing electric short-circuits.
Implementation Method 1
the stepped side pad suppresses the movement of conductive members towards the cover layer
Implementation Method 2
ensuring stable, heat-resistant bonding, thereby improving the reliability of terminal connections and preventing electric short-circuits
Data Source
AI summary
A circuit member includes a metal base, an insulating layer, a conductor, and a cover layer. A termial portion of the circuit member includes a thick portion formed at a part of the insulating layer, a conductor convex portion which is a part of the conductor, and overlaps the thick portion, and a conductor extending portion. By the conductor convex portion and the conductor extending portion, a stepped side pad is formed. The stepped side gad includes a first surface along the conductor extending portion, and a second surface which rises in a thickness direction of the conductor extending portion. The stepped side pad and an element are connected by a conductive member.