Why high Tg materials used on PCB "tweet"Want to tell me the above all, high Tg refers to the high heat resistance. With the rapid development of electronic industry, especially the electronic products represented by computer, toward high function, high multiple stratification, need PCB substrate material of higher heat resistance is an important guarantee. Represented by SMT, CMT's emergence and development of high density installation technology, make the PCB in the small aperture, fine lines, thin, more and more inseparable from the support substrate, high heat resistance. PCB substrate material under high temperature, not only produce the phenomenon such as softening, deformation, melting, also reflected in the sharp decline in mechanical, electrical properties (I think you don't want to see their products appear this kind of circumstance).Commonly so FR - 4 and the difference between high Tg FR - 4: is under the hot, especially in the heat after moisture absorption, its material mechanical strength, dimensional stability, adhesion, water absorption, thermal decomposition, thermal expansion situations vary, such as high Tg products is significantly better than the ordinary PCB substrate materials.
What is a reverse copper foil substrate ？
Traditional electroplating copper sheet is smooth and coarsening surface two part, commonly used in circuit boards, will then copper surface coarsening and resin, so that to produce, copper box resin and binding force is big, but because of the coarsening surface roughness is deeper, if to do the coarsening surface on the surface of circuit boards, are the future of the uniform rough surface can be attached with a dry film directly, need not too much before processing Try to achieve good bonding force, so the copper sheet suppliers will copper rough surface reverse turn smooth surface in addition to reinforce combined with processing, this usage is the so-called reversing the usage of copper sheet, and with smooth surface roughness is very low, so the etching is easier to clean when making fine lines, thus is advantageous to the fine line production and change a good rate, so part of the manufacturers began to should do this Use, this kind of PCB plate used in making fine lines, above are for reference only.
