I am working on my masters thesis, which involve identifying defects in manufactured VLSI ICs and PCB circuits.
In order to be able to do my research i need a fairly wide range of images of those items, so i use them as training and testing data.
So please advice me with my options and if there any source of image database for either PCB or VLSI.
How about a company that makes VLSI chips? Microchip, Atmel, Texas Instruments.. Yer gonna have to do a lot of phone research to find one that will help you with what you need though as the images you're talking about provide key information on how the chips function.
I tried googling "ic defects images" but didn't get many useful results. Then I tried something more specific; "electro migration images" and got lots of useful results. Try web searches with specific defects. You'll get more results than you will probably need.