HDI-SBU

HDI

What is a HDI?

UAn HDI PCB is defined by its high density of interconnections. HDI PCBs have thin traces and isolations, vias and microvias.

What is a buried hole?

A buried hole is a hole between several internal layers. Buried holes are usually drilled mechanically. (see HDI diagram)

What is a blind hole?

A blind hole only goes through part of the PCB, it is a non-through hole. The blind hole is made by mechanical or laser drilling. (see HDI diagram)

What is a microvia?

LeMicrovias are blind holes drilled with lasers. In most cases, a microvia is a blind hole with a diameter of 150µm or less and a height no greater than its width. The metal plating ratio of the microvia is usually 0.8 to 1.

SBU Definition

Sequential Build Up (SBU) technology is a technology used to create HDI circuits. This technology combines several successive layers in a sequence of holes. It uses buried, blind and microvias technologies to densify the interconnections.

Types of HDI features

Case I
It includes:

• Metal plated microvias (copper filled or not according to the request) and metal plated through-hole for interconnection

Case II
IIt includes:

• Metal plated microvias (copper filled or not according to the request) and metal plated through-hole for interconnection
• Buried holes

Case III

It includes:

• Metal plated microvias (copper filled or not according to the request) and metal plated through-hole for interconnection
• Buried holes
• Staggered or stacked microvias

Staggered holes may or may not be filled with copper, while stacked holes are necessarily filled with copper.

HDI diagram

Examples of use:

• Automotive
• Smartphones and tablets
• Defence and aeronautics
• Medical
• Laptop computer
• Railway
• Aerospace

For further information, please contact us