Lapping Stacked Row Bars with In-Wafer ELG Circuits
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Solution Overview
Problem
The existing process for lapping multiple row bars in hard disk drives is time-consuming and inefficient due to the need for multiple steps of attaching and removing wires to monitor electrical lapping guide resistance during the lapping process.
Innovation Solution
The method involves electrically connecting a first row bar to a carrier and an outermost row bar with electrical traces that extend through all row bars, allowing lapping and cutting without reattaching wires, reducing processing steps and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wires are attached to each row bar individually to monitor ELG resistance during lapping, then measurement precision is improved, but device complexity and processing time increase
Solution Approach 1:
Multiple wire attachment operations are merged into a single operation. The carrier is equipped with multiple bond pads that can simultaneously electrically connect to multiple row bars in the stack, eliminating the need to repeatedly attach and remove wires for each row bar lapping operation.
Solution Approach 2:
Wire attachments are performed in advance on the carrier before the lapping process begins. The carrier is pre-configured with electrical connections to multiple row bars, so that when lapping starts, all measurement circuits are already in place and ready for continuous monitoring throughout the process.
2Measurement precision
If wires are reattached for each row bar lapping operation, then measurement precision is maintained, but productivity decreases
Solution Approach 1:
The electrical measurement action continues uninterrupted throughout the entire lapping process. Multiple row bars can be lapped sequentially or simultaneously while maintaining continuous ELG resistance monitoring through the pre-established wire connections on the carrier, eliminating downtime for wire reattachment.
3Manufacturing precision
If multiple wire attachment and removal steps are performed, then manufacturing precision is ensured, but loss of time increases
Solution Approach 1:
Multiple time-consuming wire attachment steps are merged into a single preliminary setup operation. The carrier's multiple bond pads enable simultaneous electrical connections to multiple row bars, consolidating what would otherwise be repeated sequential operations into one efficient setup phase.
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 approach simplifies the lapping process by maintaining continuous electrical connections within the row bar stack, reducing the number of steps required and enhancing processing efficiency by eliminating the need for frequent wire reconnections.
Implementation Method 1
at least one electrical trace extending through at least two of the multiple row bars and electrically connected to at least one bond pad of the carrier
Implementation Method 2
lapping processes can be used to remove material at the ABS until a desired stripe height is achieved
Data Source
AI summary
An assembly for lapping multiple row bars, the assembly including a carrier having at least one carrier bond pad, multiple row bars adjacent to each other in a stack, wherein a first row bar of the stack is positioned closer to the carrier than any of the other multiple row bars of the stack and comprises at least one row bar bond pad, an electrical connection between at least one of the carrier bond pads and at least one of the row bar bond pads of the first row bar, and at least one electrical trace extending through at least two of the multiple row bars and electrically connected to at least the first row bar and one additional row bar of the stack. An outermost row bar of the stack includes an outer surface and at least one electronic lapping guide.