High density interconnect laminate technology is the product of "light, thin, short and small" and multi-functional hair layer of electronic products.There are some definite specifications on the technical indicators of relevant data reports:
1) micro-through hole (including blind hole,buried hole) diameter is Φ0.1mm or less; hole ring is less than 0.25mm; 2) the hole density of micro-through holes is greater than or equal to 600 holes/square inch; the width of the conductor is less than or equal to 0.10mm; 3) line density (set channel mesh at 0.05 inches) over 117 inches/sqr. According to the technical index, it is a feasible way to realize PCB high-density and adopt micro-conducting hole technology.Therefore, its classification is often divided according to the micro-conducting hole formation process:
Photoinduced pore-forming multilayer pcb technology
Plasma etching hole manufacturing technology of laminated multilayer pcb
Jet sand blasting process for forming porous laminated multilayer pcb
Laser pore-forming laminated multilayer pcb technology
There are three other commonly used classification methods for high density interconnect laminated pcb. One is to divide laminated pcb according to the types of media: 1) laminated pcb made of photosensitive materials; 2) laminated pcb made of non-photosensitive materials.
The second is the classification according to the electrical interconnection method: 1) electroplating microconducting hole interconnection of laminated multilayer pcb, 2) conducting adhesive microconducting hole interconnection of laminated multilayer pcb.
The third is the classification of "core pcb" : 1) with a "core pcb" structure, 2) without "core pcb" structure (no core pcb structure is in the semi-cured sheet with special technology to manufacture high-density interconnect laminated multilayer pcb).
High density interconnect laminated multilayer board (HMI) is the first manufacturing technology research result of "surface thin layer circuit multilayer board" developed by IBM in Japan in 1991. Mobile phones and laptops are now widely used.The combination of PCB classification and name is easy to understand the basic technology and process of PCB.
For the present computer city is more intuitive and fully open to see the PCB and its application, our common computer interface card is basically epoxy glass cloth base printed circuit board (because the laptop is the whole machine, so difficult to meet high density interconnect laminated pcb), one side is instrumentation components for welding surface components foot, on the other side can see solder joint very regular, discrete element these welds foot welding face we call it as a bonding pad. Why don't other copper lines have tin on them? Because except for the need of tin soldering pads and other parts, the rest of the surface has a layer of resistance to wave soldering soldering film. Its surface welding resistance film is mostly green, a small number are yellow, black, blue, etc., so in the PCB industry often called welding resistance oil as green oil.Its function is to prevent wave welding bridge phenomenon, improve soldering quality and save solder and so on. It is also the permanent protective layer of the printed circuit board, can play a role in moisture, corrosion, mold and mechanical abrasion. Seen from the outside, the surface of the smooth and bright green soldering film is photosensitive heat curing green oil. Not only its appearance is more beautiful, it is important that the accuracy of its welding disk is higher, thus improving the quality of the solder joint reliability. On the contrary screen printing soldering oil is poor.
As we can see from the computer mainboard, there are three ways to install components.The utility model relates to a transmission plug-in installation process in which electronic components are inserted into the through-hole of a printed circuit board.In this way, it is easy to see that the double-sided pcb has the following through holes: one is the simple element mounting hole; the second is the component insertion and double-side interconnection through hole; the third, the simple double-sided guide hole; the fourth is the pcb installation and positioning hole. The other two mounting methods are surface mounting and chip mounting directly.In fact, chip direct installation technology can be considered as a branch of surface mounting technology, which is to paste chip directly on PCB, and then connect it to PCB by line welding, belt loading method, inversion method, beam lead method and other packaging technologies.The soldinging surface is on the element surface.