Fabrication process(2)
Fabrication Process
이전 글에서 wafer preparation, film deposition, photo-lithography, etching을 다루었고,
이번 글에서는 doping부터 packaging까지를 정리해보았다.
Fabrication - Doping
Dopping
( Ref : Doping이 필요한 이유 / https://kycu-sb.tistory.com/54 )
n-type semiconductor : doping with P, ( -1 : 전자가 하나 많아, 전자가 떠다닌다.)
-> 떠다니는 전자를 통해 전류가 흐르도록
p-type semiconductor : doping B ( +1 : silicon보다 hole이 하나 많다.)
-> hole에 전자가 채워지면서 전류가 흐르도록
위와 같이 전자를 하나 얻거나 잃으면 전자 불균형이 생겨,
전기적 특성이 크게 띄지 않던 silicon에 전자가 흐름으로써 전류가 생기게 된다.
Doping - Ion implantation (이온 주입)
: Ion implantation is the process of adding impurities(불순물) to a Si wafer.
Photo-lithography allow us to selectively implant the region with n or p well.
이온이 Si wafer를 가격하며 해당 이온이 그곳에 들어간다.
P-well & N-well
P-well
: P-well is a region of a substrate(반응이 일어나는 부분) that is doped with impurities to create a p-type semiconductor material. P-type semiconductors have an excess of positive charge carriers, known as holes.
N-well
: N-well, onthe other hand, is a region of substrate that is doped with impurities to create an n-type semiconductor material. N-type semicoductors have an excess of negative charge carriers, know as electrons.
** P-wells and N-wells are used to create p-n junctions, which are important components in electronic devices such as diodes, trasistors, and integrated circuits. The precise positioning and doping concentration of the wells are critical to ensure the correct electrical properties of the final semiconductor device. (Previously, I mentioned that the number of outermost electrons determines the electrical properties of an element.)
Fabrication - Packaging
Chip ( or die)
- The Si wafer is then cut out using a precision diamond saw machine( cutting tool ).
- The individual IC(integrated-circuit) is called a chip or die.
IC Packaging
- Wire bonding : most widely used package interconnects with thin gold wires.
- Flip chip bonding : high performance and density interconnects with flip-chip bumps. (using heat)
PN junction
