Alignment method of a circuit board

Abstract

The invention discloses a circuit board contraposition method which includes arranging circuit graphs and contraposition graphs on a film negative in making outer layer graphs; forming circuit graphs copper foils and contraposition graphs copper foils on an outer layer board after the graphs being transferred and etched and para-positioning by utilizing the contraposition graphs copper foils in solder resisting process of the outer layer board. According to the circuit board contraposition method, the contraposition graphs transfer into the outer layer board along the transforming of the circuit graphs on the film negative, form into the contraposition graphs copper foils on the outer payer board after the processes of exposure and development; the contraposition graphs copper foils which can completely and clearly remain on the outer layer board are arranged on the outer layer board as the circuit graphs; during the solder resisting process, the exposure machine can discover the positions of contraposition graphs copper foils, so that the contraposition precision is high according to the positions of the contraposition graphs copper foils, and nearly a zero error contraposition is achieved.

Description

technical field [0001] The invention relates to the field of circuit board production, in particular to a method for aligning circuit boards. Background technique [0002] The circuit board, also known as the PCB board, has been greatly developed with the development of electronic technology, from the original single-layer board to the double-layer board, and now the most commonly used multi-layer board. Today's multilayer board manufacturing technology in the circuit board industry usually uses the following processes: material cutting → inner layer dry film → blackening and browning → lamination → mechanical drilling → decontamination and copper sinking → copper sinking and thickening Copper→outer layer dry film and graphic plating→solder resist screen printing→milling→electrical testing→finished product. Solder resist ink or character ink is mostly realized by screen printing. In silk screen printing, the alignment generally uses the peripheral pipe hole as the alignment...

AI Technical Summary

Problems solved by technology

The peripheral pipe position hole is relatively simple to make, but since the hole is drilled by a drilling machine, it is very easy to have drilling deviation and missed drilling during the drilling process.

Especially when drilling, due to the high-speed operation of the drilling machine (20,000 revolutions per minute), the temperature of the drill bit will reach about 400 degrees, and the sharply rising high temperature will melt the epoxy resin plate in the hole and form a glue. , stuck inside the round hole, resulting in the camera device of the exposure machine not capturing a complete circle but an irregular semicircle during the alignment of the solder resist process

In this way, the center of the circle cannot be captured by the camera, and the alignment will fail

In addition, when the drilling machine drills the distance of the outer rotary pipe, due to the inconsistent use of the drill tip, the circle drilled by the drill tip is not very standardized, and the post-process grinding plate, baking plate, copper sinking, electroplating and other processes are added. , the internal stress generated will elongate or shorten the circumference of the hole, and the center of the circle will change accordingly

During solder mask alignment, if the offset of the center of the circle cannot be accurately aligned, the produced board will have solder mask offset, and it will face the risk of scrapping all

Therefore, there is a great instability factor in using the peripheral tube position hole as the counter position.

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