What is the difference between CSP and COB packages

- Jun 01, 2018 -

What is the difference between CSP and COB packages?

RTD new model A40 CSP series



The biggest difference between CSP and COB is that the photosensitive surface of the CSP sealing chip is protected by a layer of glass, and the COB is not equivalent to a bare chip. There is a difference in the module height from the two processes of the same lens, and COB should be low. During production and processing, the CSP requires a relatively low dust point. If there are still dust spots on the sensor surface that can be reworked, the COB cannot.
COB Advantage: Lens, Sensor, ISP
And the soft board is integrated together, and can be directly delivered to the assembly plant after packaging and testing. The COB packaging method is a more traditional method. After obtaining the Wafer, the Chip on Board will be used to die.
Fixed to PCB board plus bracket and lens module, this production method focuses on COB
The control of yield rate has resulted in a short production process, space saving, mature technology and lower cost advantages (about 10% lower).
Disadvantages of COB: The disadvantage of COB is that it is susceptible to contamination in the production process, it has high requirements for the environment, the cost of the process equipment is high, the yield ratio changes greatly, the process time is long and cannot be maintained, etc., and if it is used in the camera module, it is dropped. During the test, there was a problem that the particles could easily come off. The production process is shortened, but it also means that the technical difficulty of the production module will be greatly increased, affecting the performance of the yield.
CSP advantages: in The package segment is completed by the front-end process. The CSP package is suitable for ICs with a small number of feet. The cost of the process equipment is low and the process time is short. CSP
The advantages include that the packaged chip size is equivalent to the die size, and is suitable for use in portable electronic products. Because only the solder balls or bumps are sandwiched between the chip and the circuit board, the circuit transmission path can be greatly shortened, and the current consumption can be reduced.
The probability of electromagnetic interference occurring. In addition, because no plastic or ceramic packaging is required, the chip can be directly dissipated from the back.
Disadvantages of CSP: The challenge is poor light transmittance, high price, high height, and ghosting phenomenon of backlight penetration.