Disk Carrier Raised Ring for CMP Edge Damage Reduction
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Solution Overview
Problem
The miniaturization of magnetic grains in hard-disk drives is limited by the superparamagnetic effect, leading to data corruption, and the mass production of patterned media disks is challenging due to edge damage during chemical-mechanical polishing.
Innovation Solution
A disk carrier with raised rings and areas is used to reduce edge damage during chemical-mechanical polishing, ensuring uniform pressure distribution and preventing excessive thinning at the disk edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical-mechanical polishing is performed to planarize the disk surface, then uniformity of the disk surface is improved, but edge damage occurs at the inside and outside diameter of the disk
Solution Approach 1:
The polishing pad is designed with varying durometer (hardness) across different regions. The first and second portions of the polishing pad adjacent to the inside and outside diameter have a first durometer, while the intermediate portion has a second durometer. This local variation in material property allows different regions to apply different polishing pressures, preventing edge damage while maintaining surface uniformity.
Solution Approach 2:
The polishing process utilizes changes in the physical parameter of the polishing pad (durometer/hardness) to control the polishing pressure distribution. By selecting materials with appropriate durometer values for different regions, the system optimizes the polishing force applied to each area of the disk, reducing edge damage while achieving planarization.
2Productivity
If magnetic grains are miniaturized to increase storage capacity, then disk capacity is improved, but superparamagnetic effect causes data corruption
Solution Approach 1:
The magnetic layer is divided into discrete, spatially separated magnetic islands rather than a continuous layer. Each island is isolated from others by non-magnetic material, preventing magnetic interference between adjacent bits. This segmentation allows smaller magnetic grains to be used within each island while maintaining data stability through physical isolation.
Solution Approach 2:
Non-magnetic material is introduced as an intermediary substance between adjacent magnetic islands. This intermediate layer provides physical and magnetic isolation, preventing superparamagnetic effects from causing data corruption by blocking magnetic field interactions between neighboring magnetic regions.
Data Source
AI summary
An apparatus, system, and method are provided for reducing edge damage of a disk during chemical mechanical polishing. The apparatus includes a disk carrier configured to receive a disk, the disk having an outside edge and an inside edge, a raised ring adjacent the outside edge of the disk and extending from a surface of the disk carrier to a height greater than a height of the disk, and a raised column adjacent the inside edge of the disk and having a height greater than a height of the disk. The system includes a disk carrier for receiving a disk, a raised ring adjacent the outside edge of each opening, and plugs insertable into a central opening in the disk and having a height greater than a height of the disk. The method includes providing the apparatus, inserting a disk into the apparatus, and polishing the disk.