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FULL CUSTOM LAYOUT DESIGN AUTOMATION USING SCHEMATIC DRIVEN LAYOUT

IP.com Disclosure Number: IPCOM000006255D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2001-Dec-19
Document File: 4 page(s) / 168K

Publishing Venue

Motorola

Related People

Mark Rencher: AUTHOR [+2]

Abstract

The requirements to improve product cycle and reduce silicon costs are constantly being evaluated, compromised and exploited. Improving product cycle time generally requires an increase in silicon, while reduced sihn size increases cycle time. These opposing objectives have been overcome with a new technique called Schematic Driven Layout (SDL). This report will discuss the development requirements of SDL and its application to full custom bipolar design.

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MOTOROLA INC. Technical Developments Volume 14 December 1991

FULL CUSTOM LAYOUT DESIGN AUTOMATION USING SCHEMATIC DRIVEN LAYOUT

by Mark Rencher and Rick Hester

   Abshact-The requirements to improve product cycle and reduce silicon costs are constantly being evaluated, compromised and exploited. Improving product cycle time generally requires an increase in silicon, while reduced sihn size increases cycle time. These opposing objectives have been overcome with a new technique called Schematic Driven Layout (SDL). This report will discuss the development requirements of SDL and its application to full custom bipolar design.

1. INTRODUCTlON

  Reducing cycle time and silicon cost are a continual opposing objectives. Improving cycle time generally requires layout tool automation such as place and route, compaction or synthesis. Using these tools however does not folly achieve the smallest the smallest amount of silicon (cost) to create a part. Because a full custom layout is most desirable from a cost perspective and achieving a reduced cycle time is desirable from a time-to-market perspective and improvement in full custom layout tech- niques to reduce cycle time is required.

  To achieve significant reductions in full custom layout cycle time while not compromising layout area, a layout methodology called Schematic Driven Layout (SDL) is developed. SDL is a technique that transposes geomet- ric information from a schematic symbol device to a parameter&d cell layout device.

  This report will discuss the geometric description which is place on schematic symbols, the geometric description of layout devices and the transposing of geo- metric information on schematic symbols to the layout device representation.

II. GEOMETRIC DESCRIPTION OF

SCHEMATIC SYSTEM DEVICES

  To achieve Schematic Driven Layout a consistent base of information must be provided on the schematic symbol. This information must be beneficial to both the schematic symbol and the layout representations. The

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basis for this consistent information is the geometric description ofthe device.

  In the past the schematic symbol required the description of the electrical characteristics through the use of Spice model references and their associated par- ameters. This information however had no direct cor- relation with the geometric information associated with the layout device. To overcome this limitation, a new modeling technique using geometric information was required.

  To provide geometric modeling of the device, the schematic symbol requires the attachment of geometric properties that fully describe the electrical and layout characteristics of the device.

An example of the geometric properties that are defined for an NPN BJT include:

ref NPN type i.e. n (NPN), nm (NPN matching), nhf(NPN High Frequency)
le Length of the Emitter
we Width of the Emitter

WC Width of the Collector np Number in parallel ne Number of emitters nb Number of bases
nc Number of collectors...