Thin-film microstrip circuits have been widely applied in microwave communications, electronic countermeasures (ECM), and aerospace applications, etc. When manufacturing thin-film ICs, it is very important to apply deposited thin-film resistor material to fabricate high-accuracy and highly stable thin-film embedded resistors. Thin-film ICs call for thin-film resistors that meet these stringent requirements:
- Square resistance should be wide enough
- Temperature coefficient of resistance should be small
- Adhesive force with substrate should be strong enough
- Thin-film resistors should feature a stable and reliable performance
- Filming should be easy and convenient
- Should be capable of handling high-temperature processing, high power and relatively wide application range.
A Brief Introduction of Embedded PCBs
The first IC invented by Jack Kilby in 1959 contained only two transistors and a resistor. Nowadays, multiple complex techniques are applied to combine tens of millions of transistors into one single PC chip. With electronic products stepping towards miniaturization and multifunction, a type of embedded passive component technology occurred to meet the increasingly higher demands. The ratio between passive components and active components is approximately 20:1, density has been gradually going up with the ratio rising. With so many passive components embedded in PCBs, the area of an SMT circuit board shrinks by 40% compared to board fabricated through embedded technology.
To read this entire article, which appeared in the June 2017 issue of The PCB Design Magazine, click here.