PCB board image transfer
PCB board image transfer
Structure of dry film photoresist
Dry film photoresist is composed of three parts of the polyester film, photoresist film and polyethylene film:
1, polyester film is supported photosensitive layer, the coating film thickness, usually about 25 M. The polyester film is removed before exposure to the development of the film, which prevents the exposure of oxygen to the resist layer, which can cause the decrease of sensitivity.
2, polyethylene film is covered on the photosensitive glue layer of protective film, to prevent dust and other dirt fouling dry film, to avoid the film roll, each layer of resist the adhesion between the film. The average thickness of the polyethylene film is about 25 m.
3, photoresist film is the main body of dry film, more negative photosensitive material, its thickness depending on its purpose, there are a number of specifications, the most thin can be a dozen microns, the thickness of up to 100 m.
The production of dry film photoresist is first to be prepared in the condition of high cleanliness, the high accuracy of the coated on the polyester film, drying and cooling, and then covered with polyethylene film, wound on a roll core.
Photo resist film composition and function: in a large amount in our country for production is full water-soluble dry film, presented here is water soluble photosensitive film layer composed of dry.
Printing etching process:
Under the material, surface cleaning, coated with the wet film, exposure, developing (paste dry film, exposing, developing), etching, to film, to enter the next process
Tian shaped electroplating process is as follows:
Metal cutting, hole drilling, hole, pre plating, surface cleaning, coated with the wet film, exposure, developing (paste dry film, exposing, developing), the formation of negative phase image, graphics plating, figure plating metal anti corrosion layer, to film, etching, to enter the next process
There are two methods of image transfer, one is the transfer of the screen printing image, one is the photo chemical image transfer.
Screen printing image transfer than photochemical image transfer cost low, more so in mass production, but screen printing resist ink usually only manufacturing printed wire is greater than or equal to o.25mm, and photochemical image for transfer of light induced resist Lang manufacturing high resolution clear image.
The content of this chapter is the latter method. Photochemical image transfer requires the use of a photoresist, and some of the basic knowledge about photoresist: