The round shapes you have seen in toys and some times in cheap calculators and wrist watches are called Chip-On-Board or COB. The silicon chip is bonded to regular PCB such as glass expoxy. The connections to the silicon die are then brought to the PCB using the bonding wires for electrical connections to the PCB in the same way as in the conventional Plasitc/Ceramic package ICs that we use commonly.

Then the Bonding glue or adhesive (black material) is applied to secure and protect the die.

The idea is to reduce the cost of packaging (plastic material and pins).

However, this COB technique is only economically feasible for mass volumes, tens of thousands of chips/dies in a lot.

That is why chips used in toys such as musical ICs, video games, calculators or even educational toy computers use this technology to reduce the cost of the product.

Thanks!

Thank you very much sir for this valuable information. Can u suggest me any Buk or reference where I can study this technology from researchers point of view ?

I do not know an book but we used to send our boards to a supplier in Goa around 10 years back. Later, either the service stopped or discontinued but then we shifted to Hongkong vendor. If I come across any book then I shall certainly send it to you.

Thanks!

Thanks sir

A good view of the chip on board assembly process is

on this set of web pages:

http://www.dieproducts.org/tutorials/assembly/cob/index.php

Hello Douglas,

Thanks for sharing wonderful piece of information.