Semiconductor device manufacturing: process – Masking – Subphotolithographic processing
Reexamination Certificate
2000-09-20
2003-03-18
Anderson, Bruce (Department: 2881)
Semiconductor device manufacturing: process
Masking
Subphotolithographic processing
C438S949000, C430S312000, C430S313000, C430S005000, C430S322000, C250S492200, C250S492220
Reexamination Certificate
active
06534425
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to fabrication of magnetic recording heads or other structures having a sloped profile or surface. More particularly, the present invention relates to photolithography reticle designs and fabrication techniques for generating sloped photoresist profiles.
As areal density in magnetic disc drive recording increases, at a rate of greater than 100% per annum, the head/disc spacing continues to shrink. The introduction of ramp load/unload, for desktop as well as mobile computer disc drives, also increases the opportunity for contact between the head and media. Without air bearing surface (ABS) designs which allow “friendly” interaction between heads and recording media, deformation of the media will result. Under extreme Pitch Static Attitude (PSA) and Roll Static Attitude (RSA) conditions, portions of the ABS and slider body are subject to contact with the recording media. This type of contact leads to burnishing of the head, which results in debris in the data zone, and/or plastic deformation of the recording media.
Sharp corners on a magnetic recording head, where the load is concentrated in a small area, have shown the highest incidence of plastic deformation of the media. In an effort to eliminate and/or reduce the amount of burnishing and/or plastic deformation, ABS designs have been modified to provide contact protection. Several features, such as pedestals, have been added to the ABS design to control the area where contact occurs. Also, in an effort to minimize the effect of controlled contact between the head and media, abrupt edges have been replaced with tapered sidewalls. To fabricate a tapered sidewall on an ABS, a tapered photoresist profile is generated, and the profile is generally transferred to the ABS during etching. Control of the resist profile angle while using a conventional chrome photolithography reticle has proven difficult.
Previous researchers have produced tapered profiles using selectively etched multi-layered masks and variable optical density reticles, both of which are costly and difficult to manufacture.
SUMMARY OF THE INVENTION
A photolithography reticle for use in conjunction with an exposure tool to produce a tapered sidewall profile in photoresist includes a solid portion and multiple sub-resolution line portions. The solid portion has a width which is greater than a resolution of the exposure tool. The sub-resolution line portions have widths which are less than the resolution of the exposure tool. Each of the sub-resolution line portions is spaced apart from the solid portion and from the others of the plurality of sub-resolution line portions by less than the resolution of the exposure tool.
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James B. Kruger et al., “Trilayer Resist”, VLSI Electronics Microstructure Science, vol. 8, 1984, pp. 91-136.
Karr Brian W.
Stover Lance E.
Zhu Jianxin
Anderson Bruce
Seagate Technology LLC
Wells Nikita
Westman Champlin & Kelly P.A.
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