What is cob (Chip on Board)? Introduction to the history of Cob

COB (Chip on Board) is a mature technology in the electronics industry, but the general packaging factory is not familiar with its manufacturing process, perhaps because it uses some wire bond (IC) technology to seal the electronic circuit, and the So a lot of finished products or professional circuit board of the foundry very difficult to find the relevant technical staff.

Previously, Cob was used mostly only in some low-tier consumer products, the smaller the product, the more companies will start to consider the cob into its products, after all, the circuit board can be used on the space of gold, and cob production can be used to a smaller than the IC space between the. Maybe it's too expensive to use advanced technology, so someone has come back to consider Cob's process.

I've re-organized many years of experience in pre-and cob-operation to remind myself of this work, and on the other hand, to provide references, and, of course, Some of the information may not be up to date, just for reference .

History of IC, COB, and Flip Chip (COG)

The following image can help you understand the history of electronic wafer encapsulation from IC seal →cob→flip Chip (COG), the size is smaller. Cob can only be said to be in the current technology of the middle of the product. In addition CSP (Chip scare package) should be a COB to Flip Chip in the middle of the process it! It's a bit messy.

Cob said to wear, that is, the IC sealed line (wire bonding) and sealing plastic (CAPLU) to the circuit board, that is to say the original adhesive to the Guide (leadframe) The bare Crystal circle (die) is glued to the circuit board (PCB), and the original welding (Bonding) to the Guide line/welding wire (wire) welding to the PCB plated gold welding mattress, and then with the epoxy to cover the wafer and guide to replace the original mold packaging, Cob can save the original ICF-encapsulated cutting foot molding (triming&form) and printing (marking) of the production process, can also be less than the IC sealing factory pipe sales, so basically its manufacturing process than the IC packaging process is cheaper.

Because it is cheap, the technology of early cob is generally only used in the low-level consumer electronics products, such as toys, calculator, small display, watches and other daily necessities, because these products are cheap so that you can use the bad to lose to buy a new one of the. As a result, the cob manufacturing process of the early Taiwan Bay was mostly made by the IC seal factory workers, the home-based OEM, the restaurant is factory, without environmental control, it is often misleading that the cob quality is this is not reliable.

However, with this time, the more and more large factories look at its small size, and the product thin and short of the trend, cob in recent years, instead of more and more broad trend, such as the mobile phone, camera and other requirements of short products there are many products into the cob manufacturing process.

Cob has another advantage that some manufacturers are particularly Chung to love. Because of the need to "seal" the relationship, the general Cob will seal all the external connectors in the epoxy resin (Epoxy), for those who like to crack the design of the hackers guests may need to spend more time to crack, the connection to the anti-hackers security and other level of Ascension. (※: Anti-hackers safety level is the amount of time spent and money to crack a technical decision, the time spent and the more money, the higher the rating)

What is cob (Chip on Board)? Introduction to the history of Cob