HDI stands for High Density Interconnection (HDI), which refers to circuit boards with dense circuits, high multi-layers, and drilling holes less than 0.15mm. HDI is manufactured using the additive layer method and micro-blind vias. It usually has 1-stage and 2-stage arbitrary interconnection forms.

HDI is often used in mid-to-high-end consumer electronics and areas with higher board requirements, such as mobile phones, notebooks, medical equipment, military aviation, etc.

1. The origin of HDI board

In April 1994, the U.S. printed circuit board industry formed a cooperative society ITRI (Interconnection Technology Research Institute) to gather various forces to research circuit board manufacturing technology. HDI was born in this society.

Five months later, in September 1994, ITRI launched research into the production of high-density circuit boards. The project was specifically called the October Project. After about three years of research, on July 15, 1997, ITRI made public the research results - publishing the October project phase 1 round 2 report that evaluated microvias, thus officially launching a new era of "high-density interconnection HDI".

Since then, HDI has developed rapidly. In 2001, HDI became the mainstream of mobile phone boards and integrated circuit packaging carrier boards.

2. 4 main differences between HDI and ordinary PCB

HDI (High Density Interconnect) is a compact circuit board designed for small capacity users. Compared with ordinary PCBs, the most significant feature of HDI is its high wiring density. The difference between the two is mainly reflected in the following four aspects.

1. HDI is smaller and lighter in weight

2. HDI wiring density is high

3. The electrical performance of HDI board is better

4. HDI boards have very high requirements for buried hole plug holes.