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# Method of Bounding and Approximating the Vertical Resistance of a Local Interconnect

IP.com Disclosure Number: IPCOM000227746D
Publication Date: 2013-May-14
Document File: 5 page(s) / 69K

## Publishing Venue

The IP.com Prior Art Database

## Abstract

Disclosed is a method of bounding and approximating the vertical resistance of a local interconnect. The method quickly establishes both a lower bound (R_lower) and an upper bound (R_upper) of the vertical resistance of a given local interconnect.

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Method of Bounding and Approximating the Vertical Resistance of a Local Interconnect

A method is needed to determine the (vertical) resistance, given all materials' dimensions and resistivity, for a local interconnect (or a structure with a liner, etc.) in a semiconductor structure.

One current solution is to run an electromagnetic (EM) field solver to produce a numerical value of R. With this solution, however, it is difficult to get a quick evaluation on the effect of an individual material's dimensions and resistivity on total resistance.

The invented solution is a simple method that can quickly establish both a lower bound ( Rlower ) and an upper bound (Rupper ) of the vertical resistance of a given local interconnect.

The novel contribution is the following formula:

Rlower < R < Rupper

(2) That also gives an approximate value of the above resistance:

R ≈ (Rlower + Ruppe)/2

Consider a rectangular shape structure consisting of two or more layers (see Figure 1). Each layer has a different resistivity, and a boundary line between two neighboring layers is either horizontal or vertical. Often the resistance value of the layered structure is obtained by running a simulation using an EM field solver. Here, the invention provides a method of obtaining a lower bound (Rlower ), and an upper bound (Rupper ) of the resistance value (R ) of the layered structure without using an EM field solver. Namely, Rlower < R < Rupper .

Figure 1: Rectangular shape structure consisting of two or more layers.

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Lower resistance bound: The method divides a given layered structure into M rows of sub-structures (see Figure 2). Each s...