This group of resource materials is designed to raise your awareness of the possibility of ESD damage sustained by components during board assembly, and give a basic understanding of the principles of ESD damage prevention and practice.
Both this section and the final (fourth) one are slightly different from usual, in that they contain questions about which you are asked to carry out some web research before reading further. Each “Search” item is linked to a typical answer, and the subsequent material has a parallel (but not identical) explanation as well as offering further insights.
The questions are designed to be answered using an internet search engine such as Google (www.google.co.uk) to search for documents relating to ESD damage prevention and ESD programs (Suggested keywords: ESD, program, electronics). A variety of web sites and other resources given at Sources of information will also provide useful information.
Answer the “Search” questions from the information in the web pages you find – you may have to search a bit and try related pages. When you find the information you are looking for, write it down, and also make a note of the source of the information in case you need to check it later.
You should assess your answers by comparing them with the key points in the linked answers (in ESD control during manufacture, also in the text which follows). Any divergence between your answer and the key points should be used as the basis for further research and discussion with fellow-students or your tutor.
a) What does the acronym “ESD” stand for?
b) Explain briefly the cause of ESD
Give three reasons why we should be concerned about ESD.
a) What is the main source of ESD in a manual assembly process?
b) What percentage of ESD damaged components has been estimated to pass tests, to be found by customers later?
c) What percentage of EOS/ESD damaged components have been found to be damaged by non-grounded people?
(Hint: see http://www.static-sol.com/61340-5-1/technical/why_worry.htm)
d) What is the approximate voltage threshold, below which a person will not feel an ESD
e) What is the target ESD withstand voltage of many integrated circuits that have on-chip protection circuits?
f) Give four types of component that may have ESD withstand voltage of less than 2,000V.
Now continue your study, first by reading Electrostatics explained,