|Parameter||Normal TG||Mid TG||High TG|
2. High Tg printed circuit board is characterized by the increase of TG of the substrate, heat resistance, moisture resistance, chemical resistance, stability and other characteristics for the board will be increased and improved. The higher the TG value, the better the temperature resistance of the board, so high Tg is widely used in the process of HASL lead-free.
3. The advantage of high TG PCB is that with the development of science and technology, electronic products are developing towards high function and high multilayer, especially the development of high-density SMT technology. PCB is more and more dependent on the support of high heat resistance of substrate in terms of small aperture, fine circuit, and thin type. In addition, the mechanical strength, dimensional stability, adhesion, water absorption, thermal decomposition and thermal expansion of high TG materials are significantly better than ordinary PCB substrate materials at high temperature, especially after hygroscopic heating.
The following table is a list of high TG PCB material commonly used by PCBONLINE. You can download the relevant information.
A. Inner layer technology: high TG, high speed, high frequency, thick copper, the thin dielectric layer and other special materials are used for the high-layer board, which puts forward high requirements for inner line production and graphic size control. For example, the integrity of impedance signal transmission increases the difficulty of inner line production. The smaller the line distance is, the more situations of the open and short circuit will be, slightly short circuit increases, the qualified rate becomes low; There are many signal layers in fine lines and the probability of missing AOI detection in inner layer increases. The thickness of inner core board is relatively thin, easy to fold and cause poor exposure, easy to roll when etched through the machine; Most of the high-layer board is system board, unit size is large, the cost of scrapping in the finished product is relatively high. PCBONLINE has carried out the technical transformation of the equipment and imported high-precision etching line equipment to improve the uniformity of etching, reduce the problems such as rough edges and unclean etching, so as to improve the quality.
B. Laminating technology: multiple inner core board and semi-solidified sheets are superimposed. Defects such as slide plate, lamination, resin cavity, and bubble residue are easy to be generated during the laminating process. In the design of the laminated structure, the heat resistance, voltage resistance, amount of glue and thickness of the medium should be fully considered, and a reasonable program of high layer board pressing should be set. Too many layers, expansion and shrinkage control and size coefficient compensation cannot maintain consistency; The thin insulation layer easily leads to the failure of reliability test between layers. PCBONLINE adopts material with different TG values in pressing, which cannot be set at the same stove. Common parameters board can not be laminated with special parameters board; To ensure the rationality of the given expansion and contraction coefficient, the performance of different board and semi-curing tablets is different, the corresponding board semi-curing tablet parameters shall be used for laminating, and the process parameters shall be verified for the special materials that have never been used.
C. Drilling technology: special board of high TG, high speed, high frequency, and thick copper are adopted, which increases the difficulty of drilling roughness and burr and defouling. Multiple layers accumulated the total copper thickness and board thickness, It is easy to break a knife when drilling a hole; In this regard, PCBONLINE has adopted the appropriate reduction of falling speed and rotation speed. Accurately measure the expansion and contraction of the board to provide accurate coefficients.
|Final board thickness||0.4-3.2mm|
|Min Drill Bit size||8mil|
|Hole size tolerance||
|Hole Position Tolerance||+/-2mil|
Line to PAD
Hard Gold Plating
SMD 40-2000u", GND 30-800u"
Au 1-5u", Ni 80-200u"
Au 1-50u", Ni 80-200u"