Abrading – Precision device or process - or with condition responsive... – Computer controlled
Patent
1997-03-03
1998-10-06
Eley, Timothy V.
Abrading
Precision device or process - or with condition responsive...
Computer controlled
451 1, 296031, B24B 4902, G11B 5127
Patent
active
058168907
DESCRIPTION:
BRIEF SUMMARY
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority from U.S. Provisional application Ser. No. 60/029,327, which was filed on Oct. 29, 1996 and is entitled ELG WIRING SCHEMES.
The present application herein incorporates by reference co-pending and commonly assigned U.S. patent application Ser. No. 08/629,524 now U.S. Pat. No. 5,722,155 to Stover et al. filed on Apr. 10, 1996 and entitled MACHINING GUIDE FOR MAGNETIC RECORDING REPRODUCE HEADS, and co-pending and commonly assigned U.S. patent application Ser. No. 08/738,693 now U.S. Pat. No. 5,755,612 to Schaenzer et al filed on Oct. 28, 1996 and entitled SMALL FOOT MACHINING GUIDE FOR RECORDING HEADS.
BACKGROUND OF THE INVENTION
The present invention relates generally to the batch fabrication of sliders which carry magnetoresistive (MR) and/or inductive transducers for data storage applications. More particularly, the present invention relates to an improved electrical lap guide (ELG) wiring configuration which allows more ELGs to be included on a row or bar of transducers to be machined, and which reduces the number of electrical connections needed between the bar and the lapping machine for a given number of ELGs on the bar.
During the fabrication of magnetic transducer carrying sliders for use in magnetic data storage systems, an array of sliders is fabricated on a common substrate in a deposition of metallic and nonmetallic layers. Typically, resistive or other elements which cooperatively function as electrical lap guides (ELGs) are also fabricated in the deposition of layers for use in lapping or machining the sliders. ELGs of various types are well known in the art. See for example, U.S. Pat. No. 5,023,991 entitled ELECTRICAL GUIDE FOR TIGHT TOLERANCE MACHINING which issued to Alan Smith on Jun. 18, 1991.
Patterning of the sliders (including the magnetic transducers) and ELGs is accomplished using photolithography in combination with etching and lift-off processes. The finished wafer is then optically and electrically inspected and subsequently cut into smaller arrays, known as rows or bars. Next, the individual bars of sliders are machined, at a surface which will eventually face the recording medium (i.e., the air bearing surface or ABS), to obtain a desired MR transducer height (sometimes referred to as the stripe height SH) or to obtain a desired inductive transducer height (sometimes referred to as the throat height TH).
During machining or lapping of a particular bar of transducers and ELGs, the machined surface moves from a beginning position to a final position, while reducing the height of the transducers. The primary function of the one or more ELGs located on the bar is to control the machining process such that the desired transducer height is achieved. After a particular bar of sliders is machined to the desired transducer height as controlled by the ELGs, the bar is cut or diced into individual sliders. During this process, the ELGs can be destroyed if desired since the purpose for which they exist has been accomplished.
Typically, each ELG includes one or more resistive elements which are fabricated in the deposition of layers along with the sliders. A very simple ELG design has one resistor which is aligned with a transducer such that the machining process reduces the height of both the transducer and the resistor at the same time. The resistance of the machined resistor (frequently referred to as the analog resistor) is monitored to determine when the desired height of the transducer has been achieved so that the machining process can be halted at this point. More common ELG designs include at least two resistive components, one machined (analog) and typically one or two non-machined reference resistors. Two or three resistor ELG's require at least three electrical access terminals on a surface of the bar in order to monitor the resistance of the ELG resistors. In some ELG designs, the resistance of each of the reference resistors is measured prior to lapping and used to calculate the local sheet resistance Q
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Hao Shanlin X.
Keel Beat G.
Stover Lance E.
Eley Timothy V.
Seagate Technology Inc.
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