Macroscopically, the effects of static electricity are broadly known: lighting, for example. Microscopically, effects include build-up of dust on TVs, clinging of clothes and a “static” shock when someone touches a cat. When friction and separation occurs between material, triboelectric generation occurs; the transfer of electrons from the atoms on the object’s surface, takes place. The resulting imbalance of electrons is known as an electrostatic charge. This charge is either positive or negative depending on deficiency or abundance of free electrons.

The amount of charge potential is influenced by the extent of the contact, the materials involved, relative humidity, and the texture of the materials. Static charges of up to 30,000 Volts are not uncommon and can be generated quite easily. In comparison, a discharge of only 10 Volts can destroy a Class 1 ESD (Electrostatic Discharge) Sensitive device. ESD damage to electronic devices may lead to premature or intermittent device failure. Studies indicate that ESD damage to electronics and associated equipment is estimated as high as $5 billion annually.

Electrostatic damage to electronic devices can occur at any point from manufacture to field service. Damage results from handling the devices in uncontrolled surroundings with inadequate ESD control practices in effect. LEDs are static sensitive devices. InGaN die are generally considered “Class 1” devices (Can survive 20 V bias w/Machine Model Testing, and 130 V from Human Body Model Testing), while AlInGaP LEDs are considered “Class 2”or better.

ESD damaged devices can appear dim, dead, shorted, or with low Vf or Vr. ESD damaged devices should not be confused with electrical overstress (EOS) induced damage caused by improper circuit design or drive, from damage incurred during die attach, wire bonding or encapsulation, or from normal environmental induced stress. The following devices have been identified by test data and/or analysis applicable to the level shown:

ESD Safety & Control (ESDS) Programs: Most electronic and electro-optics companies are very familiar with ESD and have successfully implemented ESD control, handling, and administration programs throughout their facilities. These programs have been instrumental in virtually eliminating quality defects due to ESD cause. ISO-9000 Certification is also driving the need for proper control programs. Generally, these programs include provisions for Charge Protection; Grounding; Shielding; Neutralization; Use of Anti-Static Materials, Work Stations, and other materials and equipment, and all importantly, Education. The primary method of ESD Control is to ground (or bring to the same potential) all conductors that come in contact or near proximity to the electronic device(s). These conductors include humans, tools, mats, other electronic devices, boards, connectors, packaging, etc.

Transportation & Packaging: ESD sensitive devices should always be stored in enclosed antistatic shielding bag, tote, and container when being routinely handled. This includes inventory storage, transportation, and WIP. Precautions during transportation include the use of dissipative carts, bins or other devices with conductive wheels or drag chains in conjunction with a conductive floor while transporting ESD devices. The standards used to clarify and qualify packaging materials are ANSI/ESD S11.31 – 1994 for shielding bags, ANSI/EOS/ESD S8.1 – 1993 for proper use of package markings, ANSI/EIA – 541 – 88 and ANSI/EIA – 583 – 91 for packaging materials. The Electrostatic Discharge Association can also be contacted for information on programs, methods and education.