Welding prevention method of circuit board

Abstract

The invention provides a welding prevention method of a circuit board. The welding prevention method is applied to welding prevention processing of an ultrathin circuit board. The welding prevention method comprises the steps of 1) pre-processing, and clearing foreign matter impurity on the circuit board to prevent pollution; 2) installing the circuit board on a machine table of a screen printing machine; 3) performing silk-screen printing of welding prevention ink on one surface of the circuit board; 4) baking the board in a high temperature, and completely curing the welding prevention ink printed on the circuit board; 5) performing alignment exposure and developing; and 6) repeating the steps of 2) to 5), and performing welding prevention processing on the other surface of the circuit board. In the technical scheme provided by the invention, printing, board baking, exposure and developing are respectively performed on two surfaces of the circuit board; and meanwhile, the welding prevention ink is completely curved by a mode of high-temperature board baking, no counter polymerization reaction is generated on ultraviolet light during exposure, and double images are further prevented.

Description

technical field [0001] The invention relates to the field of circuit board processing technology, in particular to a welding-proof method suitable for ultra-thin circuit boards. Background technique [0002] With the extensive application of electronic products in various industries, the production requirements for circuit boards are becoming more and more diverse. For example, in order to reduce the risk of bank cards being copied, relevant departments have pushed for financial IC cards with higher security performance in recent years. The financial IC card is a bank card with a smart chip (IC card) as the medium. The chip has a large capacity and can store information such as keys, digital certificates, fingerprints, etc., and can handle multiple functions at the same time. Features such as convenience. Due to the thickness limit of the bank card, the thickness of the circuit board used as the chip carrier is required to be controlled within the range of 0.1-0.20mm. Becau...

AI Technical Summary

Problems solved by technology

Due to the thickness limit of the bank card, the thickness of the circuit board used as the chip carrier is required to be controlled within the range of 0.1-0.20mm. Because the circuit board used as the chip carrier is too thin, when the traditional screen printing method is used to print the solder resist ink, there will be When the circuit board sticks back to the printed screen screen, the traditional thin plate solder mask production process is: pretreatment before solder mask -> print first side solder mask -> pre-baking -> print second side solder mask -> Prebaking->alignment->exposure->development, the prebaking temperature is generally about 75°C, and the time is 20 minutes to initially cure the ink, but when using the traditional process, the ultraviolet light easily penetrates to the opposite surface during exposure, causing The development is not clean, double image appears