HDI PCB Board Introduction

HDI circuit PCB or HDI boards,or High-density interconnect are printed circuit boards with a higher wiring density per unit size than traditional printed circuit boards. In general, HDI PCB is defined as PCB with following features: microvias; blind and buried vias; built-up laminations and high signal performance parameters. HDI boards are more compact and have smaller vias, pads, copper traces and spaces.

Our HDI PCB Technology is as following:

1) HDI PCB build up: 1+N+1 HDI PCB, 2+N+2 HDI PCB, 3+N+3 HDI PCB, to anylayer PCB.

2) Copper filled via, resin plugging,HDI via fill plating, via in pad technology

3) Low loss PCB materials(FR408HR, Megtron4, EM-888, TU-863+, TU-872lk, TU-872SLK, TU-872SLK SP etc)

4) High Speed Digital PCB laminate: (RF, Megtron6/R-5775, TU-883, TU-883SP, IT968SE,IT-968 etc)

5) RF PCB, Microwave pcb laminate: (Rogers series, such as RO4350B, RO4835, RO4003, RO4533, Duroid 5880, RO3203, RO3003, Taconic TLY series etc)

6) Stacked Micro-vias

7) Blind & Buried Vias

8) Laser Direct Imaging

9) 2mil Trace/Space

If we design and manufacture HDI board, we need consider following parameters:

1）Number of layers: The number of layers is related to laminates quantity, which is used in the stack-up is the most important factor when it comes to HDI manufacturing.This in turn decides the cost of the overall board.

2） Choosing laser drilling over mechanical drilling: Laser-drilled vias will reduce cost, time, and they are easy to control depth vias.

3） Aspect ratio of laser drill: The aspect ratio of the drilled vias should be smaller for easy plating and good thermal properties. This is achieved by choosing microvias that generally have an aspect ratio less than 1. The ideal value is 0.7:1.

4）Drill-to-copper: Drill-to-copper is defined as the distance between the edge of drilled hole and the nearest wire feature. Design by automation tools won't take into account the drill-to-copper clearance. When design for HDI board, the drill-to-copper capability of a manufacturer needs to be considered. The normal value of drill-to-copper clearance is 7 to 8 mils.

5) Choose the proper surface finish: ENIG or ENEPIG surface finishes are preferred over hard or soft gold for HDI boards.