Magnetic Recording Head Slider Bond Pad Segmentation
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Solution Overview
Problem
The challenge in hard disk drive components is maintaining adequate spacing between bond pads to prevent solder bridging while accommodating smaller bond pads for reliable testing and bonding, as conventional probes can scratch the metal and limit the bonding area.
Innovation Solution
The solution involves forming bond pads with a larger probe contact area and a smaller soldering contact area, where the probe contact area is distal to the mounting surface and the soldering contact area is proximal, allowing for effective probing without disturbing the soldering area and maintaining a gap between adjacent pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bond pads are made smaller to accommodate additional bond pads in an area, then the density of bond pads is improved, but the ability to test the bond pads for reliability deteriorates
Solution Approach 1:
The bond pad is segmented into two distinct regions: a probe contact area and a solder contact area. This segmentation allows the pad to serve dual functions - testing and bonding - while maintaining adequate size for reliable probing even as overall pad density increases
Solution Approach 2:
Different regions of the bond pad are assigned different functions with different size requirements. The probe contact area is made larger to accommodate probe tips and ensure reliable testing, while the solder contact area is optimized for bonding. This local differentiation resolves the contradiction between small overall pad size and adequate probe contact area
2Quantity of substance
If bond pads are made smaller to accommodate additional bond pads in an area, then the density of bond pads is improved, but the effective bonding area for solder deteriorates
Solution Approach 1:
The bond pad is divided into probe contact area and solder contact area, allowing each region to be optimized for its specific function. The solder contact area maintains adequate size for effective bonding while the overall pad density increases through compact arrangement
Solution Approach 2:
The solder contact area is specifically designed with appropriate dimensions and geometry to ensure effective solder bonding. This local optimization of the solder contact region maintains bonding effectiveness even as the overall bond pad density increases across the component
3Reliability
If a conventional probe contacts a bond pad during testing, then the bond pad can be tested for reliability, but the probe tip may scratch some of the metal off of the bond pad, thus hampering the effective bonding area
Solution Approach 1:
By separating the probe contact area from the solder contact area, the invention ensures that probing operations affect only the probe contact region. The solder contact area remains protected from probe-induced damage, maintaining its integrity for effective bonding
Solution Approach 2:
The probe contact area serves as an intermediary region that absorbs the mechanical stress and potential damage from probe contact. This intermediary zone protects the critical solder contact area from metal scratching while still enabling reliable electrical testing
4Quantity of substance
If bond pads are arranged side by side with minimum pad gap, then the density is improved, but solder during reflow may flow off of one pad and bridge the gap between neighboring pads
Solution Approach 1:
The solder contact area is designed with specific dimensional characteristics that control solder flow behavior. By optimizing the local geometry of the solder contact region, solder is contained during reflow while maintaining adequate pad density through compact arrangement
Data Source
AI summary
A method for manufacturing a magnetic recording head slider is disclosed. A plurality of bond pads are formed in a linear arrangement adjacent one another on a trailing edge of a slider body. Each of the plurality of bond pads comprises a probe contact area and a soldering contact area with each area being laterally bounded in a width dimension, along the trailing edge, by respective edges of the pads wherein a width of the probe contact area is greater than a width of the soldering contact area of each respective pad whereby the probe contact area is larger than the soldering contact area.