Hard Disk Drive Slider Pad Configuration for Solder Control
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Solution Overview
Problem
The existing bonding process for hard disk drives often results in solder overflow due to the mismatched sizes of soldering and testing pads, leading to compromised electrical connections and increased defects as the number of connections increases with new technologies, such as energy-assisted magnetic recording.
Innovation Solution
The implementation of slit-separated multiple-portion electrical connection pads, where a narrow interconnection portion for soldering and a wider probe contact portion for testing are physically distinguished by a slit, inhibiting undesirable solder flow and maintaining a controlled solder joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrical connection pad is used for both soldering and probe testing, then the device complexity is reduced, but solder overflow occurs and electrical connection reliability deteriorates
Solution Approach 1:
The electrical connection pad is divided into two distinct portions: a first pad portion for soldering connections and a second pad portion for probe testing. This segmentation allows each portion to be optimized for its specific function, preventing solder overflow onto the test portion while maintaining reliable electrical connections for both purposes.
2Ease of operation
If the pad size is increased to accommodate both soldering and testing functions, then the ease of operation is improved, but solder flow control deteriorates leading to solder bridges
Solution Approach 1:
By segmenting the pad into function-specific portions, the design allows the test portion to be sufficiently large for probe accessibility while the solder portion maintains appropriate dimensions for precise solder joint formation. The separation eliminates the trade-off between test accessibility and solder control.
Solution Approach 2:
Different portions of the electrical connection pad are designed with different dimensions and properties optimized for their specific functions. The solder portion has dimensions optimized for solder flow control, while the test portion has dimensions optimized for probe contact, achieving local quality optimization throughout the pad structure.
3Adaptability or versatility
If the number of electrical connections is increased to support new technologies, then the adaptability is improved, but the likelihood of solder defects increases
Solution Approach 1:
The segmented pad design can be systematically applied to multiple electrical connections across the slider. Each connection point benefits from the separation between solder and test portions, and this scalable approach maintains consistent quality control as the number of connections increases to support advanced technologies like energy-assisted magnetic recording.
Data Source
AI summary
A hard disk drive head slider housing a read-write transducer includes a plurality of electrical connection pads, where each electrical pad includes an interconnection portion configured for electrically connecting to an interconnected component, such as a lead suspension, a probe contact portion configured for electrical testing the head slider, and at least one slit positioned between the interconnection portion and the probe contact portion, thereby physically distinguishing and separating the two portions of a multiple-portion pad to inhibit undesirable solder flow to the wider probe contact portion on the slider side of each pad. A more controlled solder joint is provided, while the probe contact portion can remain relatively wide for probe contact and the interconnection portion can remain relatively narrow to reduce solder bridges among the pads.