Automated Design for Micromachining

# Resistor

## Introduction

This cell implements a simple resistor. The resistor is a straight length of minimum width POLY0.

Please also read the documentation for the snake resistor parameterized cell.

Figure 1: Layout for a PolyMUMPS resistor. The length is 100um and presents a resistance of ~1300Ω.

Model 1: Pin design (20um x 20um).

## Theory

The resistance between the terminals can be calculated using the following formula:

(1)R=lρ/wt

Where, R is the resistance between terminals, l is the length of POLY0 separating the terminals, ρ is the resistivity of the POLY0, w is the width of the POLY0, and t is the thickness of the POLY0.

The values for ρ and t are process dependent, and can vary from process run to process run. However, for the PolyMUMPs® process they have nominal values of 0.5um for t [1] and 1.3×10-3Ωcm. With34 the default length of 100um, the resistor would thus have a resistance of approximately 1300Ω.

## Parameters

Any parameter may be modified, if necessary, to meet design rules. Typically, this involves increasing parameters that specify distances, so that minimum line width and minimum line spacing rules will not be violated. This has been extended to the convention of specifying a zero for some parameters to obtain an instance of the minimum size.

In addition to the parameters listed below, several technology parameters also influence the implementation of parameterized cells. This data must be present in the technology library.

Table 1: Parameters for the 'resistor' parameterized cell.
Name Description Range Units
length This is the length of the POLY0 resistor. Increasing the length will increase the resistance. [0,∞) um
width This is the width of the POLY0 resistor. Increasing the width will decrease the resistance. [0,∞) um
pin size At each end of the resistor is a pin. This parameter controls the side length of the pins. More details are available in the documentation for the pin parameterized cell. [0,∞) um
chamfer This is the length along each corner that will be chopped. Typically, this parameter should is zero. However, it can be increased to reduced spurious DRC violations in non-manhattan geometries. [0,∞) um
include R If this box is checked, the pcell will calculate the resistance of the device using standard MUMPS parameters (as above) and display the value using the TMP layer. true/false -

## References

[1] David Koester, Allen Cowen, Ramaswamy Mahadevan, Mark Stonefield, and Busbee Hardy. PolyMUMPS Design Handbook: 9th Ed. MEMSCAP, Bernin, France, 2003.