What is Chip On Board (COB)

By Bester PCBA

Last Updated: 2023-08-07

What is Chip On Board (COB)

COB, short for Chip On Board, is a packaging technology widely used in the PCB industry. It involves mounting bare silicon chips, typically integrated circuits, directly onto a circuit board without individual encapsulation. Instead of a traditional package, COB chips are covered with a blob of black epoxy or a transparent epoxy/silicon caulk-like material in the case of LEDs.

The COB process offers several advantages. Firstly, it allows for multiple chips to be connected in parallel and placed on a common substrate, resulting in higher efficiency and power density compared to conventional chips. This makes COB chips particularly suitable for applications requiring compact form factors. Additionally, COB technology has gained popularity in lighting applications due to its ability to provide higher light output while consuming less energy.

COB eliminates the need for the original IC packaging Trimming & Form and marking processes, leading to cost savings for IC packaging factories. This makes the COB process generally more cost-effective than traditional IC packaging methods. Over time, COB has evolved to be used in smaller electronic products more effectively than IC packaging.

Frequently Asked Questions

Is PCB a Chip

A PCB, or printed circuit board, is a flat plate made of fiberglass with copper traces that are used to connect electronic components together. On the other hand, a chip refers to a small piece of semiconductor material, typically silicon, that contains a set of electronic circuits.

How Are Chips Connected to PCB

Chip on board assembly is a process where bare semiconductor chips are mounted onto a PCB or substrate. To achieve electrical connection, the manufacturer utilizes either aluminum wedge bonding or gold ball bonding.

What Are the Advantages of Chip on Board

The benefits of using chip on board (COB) technology include eliminating the need for IC packaging trimming, form, and marking processes. This results in cost savings for IC packaging factories and makes the overall process more affordable compared to traditional IC packaging methods.

What Are the Disadvantages of Chip on Board

Chip on board technology offers various advantages compared to wire connections, including lower cost and size, as well as increased reliability due to fewer potential points of failure. However, it is important to note that chip on board also has certain drawbacks, such as limited heat dissipation. This is primarily due to the proximity of the components to the chip, which results in most of the generated heat being concentrated in that area.

What Is COB in Semiconductor

Chip-on-board (COB) technology refers to the process of directly attaching a semiconductor die to a PCB substrate using adhesive. The die is then wire bonded to an existing circuit pattern on the board before being encapsulated.

How Is a COB Chip Made

The main process used in the production of a COB (Chip On Board) chip is Wire Bonding and Molding. This technique involves packaging the exposed integrated circuit (IC) as an electronic component. To extend the I/O of the integrated circuit (IC), Wire Bonding, Flip Chip, or Tape Automatic Bonding (TAB) can be used to connect it to the trace of the package.