High Density Interconnects (HDI) board are defined as a board (PCB) with a higher wiring density per unit area than conventional printed circuit boards (PCB). They have finer lines and spaces (<100 µm), smaller vias (<150 µm) and capture pads (<400 µm), I/O>300, and higher connection pad density (>20 pads/cm2) than employed in conventional PCB technology. HDI board is used to reduce size and weight, as well as to enhance electrical performance.

According to layer up different, currently DHI board is divided into three basic types:

1) HDI PCB (1+N+1)

Features:

• Suitable for BGA with lower I/O counts
• Fine line, microvia and registration technologies capable of 0.4 mm ball pitch
• Qualified material and surface treatment for Lead-free process
• Excellent mounting stability and reliability
• Copper filled via

Application: Cell phone, UMPC, MP3 Player, PMP, GPS, Memory Card

1+N+1 HDI PCB Structure:

2) HDI PCB (2+N+2)

Features:

• Suitable for BGA with smaller ball pitch and higher I/O counts
• Increase routing density in complicated design
• Thin board capabilities
• Lower Dk / Df material enables better signal transmission performance
• Copper filled via

Application: Cell phone, PDA, UMPC, Portable game console, DSC, Camcorder

3) ELIC (Every Layer Interconnection)

Features:

• Every layer via structure maximizes design freedom
• Copper filled via provides better reliability
• Superior electrical characteristics
• Cu bump and metal paste technologies for very thin board

Application: Cell phone, UMPC, MP3, PMP, GPS, Memory card.