Electrostatic Discharge Sensitive Devices Research Articles

Development of functionalised foam for electrostatic discharge applications

ABSTRACT Electrostatic discharge-sensitive devices (ESDS) consist of electronic systems that are easily damaged by electrostatic fields or discharges. To safely stow and transit the ESDS, Bosch Car Multimedia S.A. resorts to thermoformed trays with a specific design for each product configuration. Although efficient, the solutions’ specificity arose logistic issues that created the need for an alternative approach. This paper reports the investigation for the development of a flexible tray, based on an electrostatic-dissipative integral skin foam. First, a commercial integral skin polyurethane foam was evaluated by varying components mixing ratio. Once achieved a suitable combination of hardness and density, post-formulation additives (colour and anti-static) were investigated. Free expansion foaming stages were assessed and cured foams were characterised in terms of electrostatic discharge protection. Moulded foams with variable patterns were developed and evaluated considering the application purpose requirements. Real-scale prototypes of the most adequate concept design were produced and analysed.

Can Electrostatic Discharge Sensitive electronic devices be damaged by electrostatic fields?

In recent years the susceptibility of ElectroStatic Discharge Sensitive devices (ESDS) to electrostatic fields has been questioned. This paper proposes that very high impedance voltage sensitive ESDS such as MOSFETs or MOS capacitors can be damaged due external field changes without making contact with other conductors in the presence of the field. A simple electronic model is proposed. In a practical evaluation of this risk, discharges are demonstrated to occur due changing external fields, as a result of breakdown of a voltage sensitive structure in a high impedance circuit with one terminal continuously grounded.

Characterization of ESD shielding materials with novel test methods

Electrostatic discharge (ESD) shielding effectiveness of materials used to protect ESD sensitive devices was evaluated with a coaxial electrode and ESD generator. Attenuation of a continuous low power signal and a high power transient was measured. Electromagnetic far field shielding does not necessarily address ESD protection performance. High impedance on a discharge path reduces energy coupling efficiently. Therefore the prevention of conductive and capacitive coupling is the key factor for designing protective packaging for transportation of ESD sensitive devices. Due to the effect of breakdown field strength, low power signals shall not be used alone to assess ESD shielding characteristics. A coaxial electrode and an ESD generator was found a useful combination for the evaluation of ESD shielding effectiveness. As a final outcome, adequate ESD protection can be achieved even without the far field shielding, depending on application.

Peak current failure levels in ESD sensitive semiconductor devices and their application in evaluation of materials used in ESD protection. Part 1: Theoretical analysis

This paper shows that theoretical analysis of the thermal model of damage to electrostatic discharge (ESD) energy susceptible devices combined with data from Human Body Model test on devices can be used to estimate an ESD pulse current threshold for damage to ESD energy susceptible semiconductor devices over a wide range of ESD duration and waveforms. The technique is intended for laboratory evaluation of ESD threats from equipment, materials and other ESD sources in the electronics assembly factory environment. In Part 2 of this paper the predicted ESD current damage threshold is experimentally demonstrated to give a useful boundary to a ‘safe’ area of ESD current and duration.

The Effects of Electrostatic Discharge on Microelectronic Devices A Review

Electrostatic discharge (ESD) can cause permanent and temporary failures in microelectronic devices. Protection networks are used on electrostatic discharge sensitive devices in order to raise their immunity to damage from ESD. A review is given of the causes and nature of ESD, including the case of discharge from the human body. A description of failure mechanisms is presented along with a summary of protection networks and techniques.