Camera module packaging technology

The camera module is a crucial electronic component for image capture, mainly consisting of a lens, a focusing motor, a base bracket, a photosensitive chip, a driver chip, an output interface and other parts. The main packaging technologies of camera modules include COB (Chip On Board), CSP(Chip Scale Package), and FC(Flip Chip), among which COB is currently the mainstream packaging method. COB refers to the process of mounting chips on the module substrate and then completing electrical connections through metal wire binding. Its main advantages are prominent, featuring small size and low height. Moreover, compared with the standard SMT process, COB can reduce the manufacturing cost of products. The disadvantages are strict requirements for cleanliness, low yield rate and long production process time. CSP is mainly applied to low-end products, while FC is only used by Apple.

Wire bonding

The COB process flow mainly includes cleaning the PCB, dropping adhesive, chip bonding, wire bonding, sealing adhesive, and testing. Each step is of vital importance. After the chip surface mount of the camera module is completed, the electrical connection between the chip and the substrate needs to be achieved through wire bonding. Ultrasonic waves generate high-frequency vibrations. Under the action of pressure and ultrasonic waves, the surfaces of the metals to be welded rub against each other, the oxide film is destroyed and plastic deformation occurs, causing atomic diffusion between the two metals and close contact. Finally, the internal circuits of the chip are connected to the pins of the packaging substrate through gold wires, and then sealed with special materials to protect the chip. The stability of wire bonding technology is related to the signal extraction of the chip and the yield of the lens during the subsequent finished product testing.

The Flick20 wire bonding machine produced by Devol Advanced can effectively enhance the stability of the camera module packaging and wire bonding process. The Flick 20 adopts the thermoultrasonic wire welding method. The welding speed can reach 22 wires per second, and the image recognition accuracy is ±0.37μm. It can be applied to various types of wires such as copper wire, palladium-plated copper wire, low alloy wire, and gold wire. The Flick 20 wire bonding machine is simultaneously equipped with a new type of high-speed identification device, achieving a controllable vibrating XY platform with low vibration and a high-speed wire bonding head with low inertia. Supports programming functions for complex wire welding programs and features the industry's most comprehensive arc library, such as spatial zigzags and ultra-low arcs. It is applicable to various packaging forms such as SOT/SOP/MEMS/DFN.