ESD Flooring: An Engineering Evaluation

Study By:

Donna Robinson-Hahn AT&T Microelectronics Allentown, PA

ABSTRACT

Staticworx® , superior in performance.

An integrated circuit (IC) can suffer catastrophic damage from as little as 50 volts while manufacturing personnel can generate over 10,000 volts by simply walking across a production floor.  This paper reports the results of an extensive two year study of over twenty reportedly ESD-safe floors that are used in combating this threat.

INTRODUCTION

A top executive slides her chair across her office to pick up a phone where a key customer is waiting to discuss a possible contractor.  Her hand makes contact with the receiver and the line goes dead.  Meanwhile, an engineer works on a CAD system, completing an intricate design when suddenly the system goes down.  The design is lost.  Just an isolated incident?  Think again.

A person walking across a standard vinyl tile floor can generate in excess of 10,000 volts.  Integrated circuits can suffer catastrophic damage from as little as 50 volts.

To combat this threat, the use of ESD-safe flooring, in conjunction with ESD footwear has become a reality for today’s electronics industry.  To meet this need, a variety of reportedly ESD-safe flooring materials have become commercially available which are intended to minimize the magnitude of charge generation.  As part of this study, various types of ESD flooring materials were installed in an AT&T Allentown manufacturing area and tested over a period of 2 years.  The test methodologies and results for each flooring type are reported and compared in this paper.

ESD BASICS

Electrostatic charge is typically generated when two dissimilar materials are brought into contact and then pulled apart, such as rubbing.  When separated, one object will exhibit a net positive charge, the other a net negative charge.  The exact magnitude of the charge is a function of the materials and of parameters such as surface texture, relative humidity, contact force, etc.  The accumulation of charge causes a static potential to develop.  A common example of frictional charging is the potential developed on a person walking across vinyl flooring or rolling a char across carpet.  The magnitude of the voltage build-up is a function of flooring material, shoe sole material, relative humidity, weight of the person, the capacitance with respect to ground, etc.  If the charged person then touches a sensitive electronic part, or if one grounds the part in the presence of a charged source, and Electrostatic Discharge (ESD) transient occurs that may damage or degrade the sensitive part.

Next: Experimental Overview

Introduction | Experiment Overview | Procedures | Results | Economics | Summary | Conclusion | Credits