Blind & Buried Vias

What's Blind and Buried Vias/Via-In-Pad?

A via interconnect hole that resides in a solderable pad, where the requirements are for a flat, planar surface that does not contribute negatively to the placement or orientation of the soldered component.

Common Method of Creating Via-In-Pad

  1. Using mechanical drills, the via spans one or several dielectrics and conductive layers, and is filled (post-plating) with a conductive or non-conductive epoxy material that is void-free and facilitates a planar surface to create the surface pad that a device will be soldered to.
  2. Using laser ablation, the micro via spans a single dielectric and connects the surface layer to the next layer down in the stackup (except variable-depth micro vias). The subsequent micro via is fully copper plated and planarized to create a flat surface pad that a device will be soldered to.

Micro Vias

  • TYPE I (1 + n + 1) - Laser micro vias on both sides of the board.
  • TYPE II (1 + n +1) - Laser micro vias on both sides of the board, with buried vias in the core.
  • TYPE III ( 2 + n + 2) – Laser micro vias on both sides of the board, may have buried vias in the core.

Via Fill Materials

Conductive (Type: Silver Coated Copper Particulates):

  • DuPont CB-100
  • Tatsuta AE3030

Non-Conductive Epoxies:

  • San-Ei Kagaku PHP-900 IR10F
  • Peters PP2795
Printed Circuit Board stacked microvias Best in class overall end-user performance with San-Ei IR-10F product.
Printed Circuit Board stacked microvias Very high copper peel strength.
Printed Circuit Board stacked microvias Low CTE above tg of the laminate material.
Printed Circuit Board stacked microvias Excellent performance at elevated temperatures.

Note: Non-conductive CTE is comparable to FR4 material. It is preferred to use non-conductive via fill unless thermal conductivity is the requirement. Filled via drilled sizes:  Smallest .008    Largest .020

Serving the Medical, Aerospace/Defense, Commercial, and All Other PCB Markets
Advanced Circuits has become well known as an industry leader in printed circuit board manufacturing and Assembly due to our commitment to provide the highest standards in quality, performance, and reliability in every circuit board we manufacture.  Advanced Circuits is also one of the few PCB manufacturers in the U.S. that is able to produce printed circuit boards for DOD Contracts.
PCB capabilities for medical devices | Advanced Circuits    PCB capabilities for military aerospace | Advanced Circuits    PCB capability for commercial devices | Advanced Circuits             

New Advanced Circuits PCB Board Materials!

These new materials can be utilized for: Integrity Designs requiring miniaturization, Advanced HDI, Stacked Microvias, Antenna and Aerospace, Multilayer Advanced RF and Microwave. Advanced Circuits is one of the select few fabricators in the United States certified to offer Integral Technology's Zeta Lam high density interconnect product.

  • Halogen-free UL Certified materials
  • High Speed / Ultra Low Dk & New RF Products
  • Rogers 2929 Bondply
  • 3M ECM (Embedded Capacitance Material) - Click Here for more info
  • Zeta Lam SE - Click Here for more info

You can trust Advanced Circuits to provide in-depth information on this and many more subjects relating to the manufacture and assembly of printed circuit boards. Find out more about High Performance Materials for Advanced Designs in our Tech Talk for Techies report. It discusses materials that provide greater thermal performance and severe environment reliability.  Click Here to see Part 2 of the report.