Browse Prior Art Database

Extended Guard Bands for Skipping Presputter Contamination Magnetic Defects

IP.com Disclosure Number: IPCOM000115996D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Buhler, A: AUTHOR [+4]

Abstract

Presputter Contamination (PSC) magnetic defects occur when contamination is present on the substrate prior to sputtering the magnetic layer. The sputtered magnetic layer then may have poor adhesion and possibly protrude up leading to an asperity. It usually is sputtered as a continuous film, however post processing of the disk often leads to the film to be partially (but not completely) broken (Fig. 1). The areas which are broken will be skipped at SAT; but the poorly adhered adjacent regions which can be written and read successfully will not be skipped - the danger then is that if these break open due to say a head flying over it or corrosion, customer data can be lost.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 79% of the total text.

Extended Guard Bands for Skipping Presputter Contamination Magnetic
Defects

      Presputter Contamination (PSC) magnetic defects occur when
contamination is present on the substrate prior to sputtering the
magnetic layer.  The sputtered magnetic layer then may have poor
adhesion and possibly protrude up leading to an asperity.  It usually
is sputtered as a continuous film, however post processing of the
disk often leads to the film to be partially (but not completely)
broken (Fig. 1).  The areas which are broken will be skipped at SAT;
but the poorly adhered adjacent regions which can be written and read
successfully will not be skipped - the danger then is that if these
break open due to say a head flying over it or corrosion, customer
data can be lost.

      Extensive failure analysis of PSC defects show a unique
character which allow for an extended guardband algorithm which
protect the customer from the majority of such defects.  It has been
determined that the open regions lead to sequential errors of length
"L" much longer than other typical (e.g., substrate scratches)
magnetic defects.  The specific lengths will depend upon the
manufacturing processes, but generally L > 5 microns.

      Failure analysis also demonstrates statistics on the diameter
or characteristic width "w" of PSC.  These statistics will depend on
the manufacturing process but are typically larger than the track
pitch, generally w > 50 microns.

      The extended guard band...