Introduction to Advanced PCB Technology (2)

C. Fine line production technology
Another feature of high-density PCB circuit boards is that they have very small line widths and line spacings. To make lines below 4 mil, it is difficult to use the traditional stereotype machine, and the stereotype liquid is difficult to achieve. It needs to use advanced DES (Development, Etch, Release) line, and cooperate with suitable dry film and exposure technology to achieve. The research focuses on the production of 3mil/3mil line width and line spacing, and then studies 2mil/3mil, 2mil/2mil.

2. Thermosetting Ink Lamination Technology (TCD technology for short)
TCD technology is a new technology of making the SBU layer in the HDI board by using the method of full-board electroless copper deposition after the silk-screen thermosetting ink instead of the pressing plate method.
The advantages of TCD technology are:
A. The SBU layer dielectric thickness is adjustable. No matter how thick the dielectric layer is required by the user, it is necessary to use the thicker thermosetting ink to screen printing, instead of being limited by the fixed thickness of the semi-solid film.
B. Laser drilling is easy to achieve. Because the main component of the ink is resin and does not contain glass, the laser energy required is lower and more stable than the epoxy glass cloth in the prepreg, so the laser drilling is easy to control.
C. Manufacturing costs are greatly reduced. Because the laser drilling glass cloth technology is difficult to control, some manufacturers first use the copper foil with semi-cured resin (RCC) without glass cloth to press the plate. This kind of RCC is only produced in Japan and is expensive, so using TCD technology can achieve the same effect without using RCC.
D. Simplify the production process. In the TCD process, laser drilling can be used directly after printing the ink. If other materials such as RCC are used, the copper window must be opened at the position to be drilled on the board before laser drilling can be performed.