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Method for quantitative parameterization in custom interconnection design

IP.com Disclosure Number: IPCOM000015415D
Original Publication Date: 2002-Nov-15
Included in the Prior Art Database: 2003-Jun-20
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Abstract

Self-consistent formalisms are disclosed for intervention with pre-route algorithms in ULSI designs and for quantifying the physical properties of routes prepared with a pre-route algorithm. Disclosed are: (1) New measures of interconnect complexity to characterize individual interconnections and to characterize the set of interconnections in a design layout; and (2) A method for intervention with a pre-route algorithm. The term interconnect complexity refers to the physical characteristics of interconnections in a wire configuration for a design. Measures of interconnect complexity of a wire configuration for all routes in a design include: (1) total excess Steiner length TESL, (2) total excess Manhattan length TEML, (3) Steiner quality Q S , and (4) Manhattan quality Q M . TESL is obtained by subtracting the total Steiner length for all signals from the total netlength for all signals. TEML is obtained by subtracting the total Manhattan length from the total netlength. The Steiner quality Q S is the ratio of the total Steiner length to TESL, and the Manhattan quality Q M is the ratio of the total Manhattan length to TEML.

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Method for quantitative parameterization in custom interconnection design

   Self-consistent formalisms are disclosed for intervention with pre-route algorithms in ULSI designs and for quantifying the physical properties of routes prepared with a pre-route algorithm. Disclosed are: (1) New measures of interconnect complexity to characterize individual interconnections and to characterize the set of interconnections in a design layout; and (2) A method for intervention with a pre-route algorithm. The term interconnect complexity refers to the physical characteristics of interconnections in a wire configuration for a design. Measures of interconnect complexity of a wire configuration for all routes in a design include: (1) total excess Steiner length TESL, (2) total excess Manhattan length TEML, (3) Steiner quality QS, and (4) Manhattan quality QM. TESL is obtained by subtracting the total Steiner length for all signals from the total netlength for all signals. TEML is obtained by subtracting the total Manhattan length from the total netlength. The Steiner quality QS is the ratio of the total Steiner length to TESL, and the Manhattan quality QM is the ratio of the total Manhattan length to TEML.

Measures of the complexity of each individual interconnection include: (1) normalized excess Steiner length NESL; (2) normalized excess Manhattan length NEML; (3) average normalized excess Steiner length <NESL>, and (4) average normalized excess Manhattan length <NEML>. NESL for each signal is obtained by subtracting the Steiner length from the signal netlength, and then dividing this term by the signal Steiner length. NEML for each signal is obtained by subtracting the Manhattan length from the signal netlength and then dividing this term by the signal Manhattan length. For each signal, NESL measures how well the actual wire length approximates the length estimate provided by the Steiner algorithm. In our experience, signals with high NESL tend to be found in regions with high values of signal density and via density relative to values in neighboring regions. For a group of signals, <NESL> is the average of the NESL for the signals in the group; similarly, <NEML> is the average of the NEML for the signals in the group.

The method for intervention with a pre-route...