WSI-1022 WS57C128 WS57C191 WS57C291 WS57C43 WS57C49 WS57C51 - Datasheet Archive
WSI-1022 September 22, 1998 Subject: Critical Process Change Notification High Speed Memory (35ns and slower only) Device Types:
Document: WSI-1022 WSI-1022 September 22, 1998 Subject: Critical Process Change Notification High Speed Memory (35ns and slower only) Device Types: WS57C128 WS57C128, WS57C191 WS57C191, WS57C291 WS57C291, WS57C43 WS57C43, WS57C49 WS57C49, WS57C51 WS57C51 - This change effects speeds 35ns and slower only (-35, -45, -55, -70 and -90) * 25 ns versions are not effected by this change * Overview In order to take advantage of more modern manufacturing equipment and thus increase production capabilities, WSI is in the process of converting the High Speed Memory devices listed above from 5" wafer to 6" wafer fabrication. Since both wafer lines (5" and 6") are located in the same fabrication facility and identical wafer masks are used, the change is considered very minor. Details The identical physical mask sets have been used to produce the wafers. Therefore, the design, layout, pad placement and die size are also identical to the existing versions of these parts. The Assembly process and packaging materials are unchanged. The wafer sort and final test flows are unchanged. The basic fabrication process is the same, with one minor exception: The thickness of the material used as a dielectric between the poly 2 and metal, BPSG, was changed from 9000 angstroms to 7500 angstroms on the 6" flow. The equipment and even more importantly, the chemical makeup of the BPSG itself remains the same; only the deposition thickness was changed. The 6" line has been qualified by WSI, and no reliability issues were uncovered. Part Number Change WSI considers these changes to be of such a benign nature that there will be no part number revision for these products. However, complete traceability is insured via bottom side marking for use by WSI. Production Plans WSI plans to begin production shipments of the 6" wafer material to all customers over the next several months: Device WS57C128 WS57C128 WS57C191 WS57C191, WS57C291 WS57C291, WS57C51 WS57C51 WS57C43 WS57C43, WS57C49 WS57C49 Package D, J, L, C D, J, P, C D, J, S, T Engineering Samples October, 1998 November, 1998 October, 1998 Production Shipments January, 1999 January, 1999 November, 1998 Additional Information and Comments If you require any additional information, qualification samples have any concerns or issues, or have a question, please contact your local WSI sales representative or send WSI an e-mail at email@example.com. Thank you for your continued support.