Blind vs Buried Vias: PCB Manufacturing Cost Explained

Deciding whether to use blind vs buried vias, or good old fashioned through-hole vias is one of the most impactful choices you will make during PCB design. It also has a direct impact on how much your board will cost to manufacture.

Production of multilayer boards with blind or buried vias will be 40–100% more expensive than an equivalent design that utilises through-hole vias exclusively. But for high-density boards that support BGAs or have strict signal integrity requirements, sometimes they’re necessary.

But when are they really necessary? And is there anything you can do to minimise their impact on your PCB budget?

In this article, we cover:

• What are blind and buried vias?
• Why blind/buried vias cost more to manufacture
• Blind vs buried via cost comparison
• How blind/buried via costs can be reduced with proper design techniques
• When you should avoid using blind/buried vias
• Blind vs buried vias: impact on PCB reliability

What Are Blind and Buried Vias?

It’s helpful first to define exactly what differentiates blind and buried vias from one another as well as from standard through-hole vias.

Through-Hole Via

A through-hole via is simply a hole drilled all the way through the PCB, from top layer to bottom layer. They are by far the most common, simplest type of vias used in PCB fabrication.

Blind Via

A blind via connects the top or bottom layer of the PCB to one or more inner layers. They do not go all the way through the board. These vias are visible from one side of the PCB only.

Buried Via

Buried vias connect two or more inner layers of a PCB without reaching either of the outer layers. They are completely hidden inside the PCB and cannot be seen from either side of the board.

Why Blind and Buried Vias Cost More: The Full Story

Ok, so now that we know what blind and buried vias are. Why do they cost so much more money to fabricate?

1. Extra Lamination Stages

Traditional PCBs are laminated using just a single press cycle. Boards with blind and buried vias require multiple, sequential lamination cycles. The inner layers of the board are built up first, drilled, plated, and laminated. Then the final outer layers are applied along with any blind vias.

Each stage of the process requires:

• Separate press time
• Alignment
• Inspection

A complex eight-layer HDI board with both blind and buried vias could require 3 or even 4 separate lamination cycles. Every lamination stage adds risk and expense to the fabrication process.

2. Special Drilling Techniques

Whereas through-hole vias are drilled using standard mechanical drills, blind vias (and buried vias that must be drilled before lamination) often require one of the following:

• Laser drilling: Microvias (any via ≤150µm in diameter) require laser drilling. This process is slower and uses more expensive equipment than mechanical drilling.
• Controlled depth drilling: Drilling blind vias mechanically is possible, but the drill must stop at the desired depth without breaking through to the next layer. The process requires tighter tolerances and much slower feed rates.

In both cases, more machine time is required and expensive, specialised equipment is necessary.

3. Additional Plating and Cleaning Steps

After drilling and before each lamination cycle, each group of vias needs to be cleaned, copper-plated, and then inspected before moving on to the next stage. This means the PCB needs to go through the plating line multiple times instead of once.

4. Higher Scrap Rates

As you might expect, when you complicate the fabrication process by adding sequential lamination and precision drilling you run the risk of introducing defects. Boards can be scrapped due to misregistration between lamination steps, poorly completed plated via barrels, and drilling depth errors. Manufacturers take this increased scrap rate into consideration when pricing these boards.

IPC estimates that yield loss on HDI boards (with blind/buried vias) can increase costs by 10–25%, depending on board complexity.

Cost Comparison: Blind vs Buried vs Through-Hole Vias

Factor	Through-Hole Via	Blind Via	Buried Via
Lamination Cycles	1	2 or 3	2 or 4
Drilling Process	Mechanical	Laser or Controlled Depth	Mechanical (Pre-lamination)
Typical Cost Increase	~$0 (Baseline)	+30-60%	+40-80%
Combined (Both)	N/A	N/A	+50-100%
Lead Time Impact	Little to none	Adds 3-5 working days	Adds 3-7 working days
Order Sensitivity	Low	Moderate	High (fixed costs)

* These numbers are indicative. Actual costs vary based on layer count, via quantity, dimensions, and manufacturer capabilities.

When to Use Blind and Buried Vias?

OK, so they’re expensive. When should you bite the bullet and use them anyway?

• If Routing Density Requires It: BGAs with fine pitch pads (≤0.8mm) are often too dense to route using through-hole vias alone.
• Size Is Limited: Space is at a premium for wearables, medical implants, and aerospace. You can often reduce overall board size by converting through-hole to blind/buried.
• Signal Integrity is a Concern: The stub nature of through-hole vias introduces impedance discontinuities. Using blind vias eliminates stubs for high frequencies (>~3GHz).
• You Need An HDI Stackup: If your design calls for an HDI build, you will be using blind and buried vias anyway.

Avoid Blind and Buried Vias If:

1. Routing can be achieved with through-hole vias.
2. Prototyping budget is tight.
3. Your manufacturer cannot fabricate them.

Reduce Blind vs Buried Vias Cost With These Tips

1. Reduce Lamination Cycles as Much as Possible

Design your layer stackup such that blind/buried vias can be fabricated using the least amount of sequential lamination cycles possible. For an eight-layer board, use blind vias that connect only layer 1 to 2 and layer 7 to 8.

2. Use Microvias instead of Deep Blind Vias

Microvias are by far cheaper to fabricate. Since they typically traverse only one layer, they can be laser drilled in a single step. Where possible, replace traditional blind/buried vias with staggered or stacked microvias.

3. Keep Your Via Sizes Standardised

The more different drill sizes you use, the more times your PCB manufacturer will need to change out drill bits/laser heads.

4. Talk to Your PCB Manufacturer Early

Ideally, you should consult with your PCB manufacturer during the design phase. At PCB Company, we offer free design reviews with our PCB engineering team to see where costs can be reduced.

5. Avoid Via-in-Pad If Possible

This technique requires that the via be filled with epoxy, planarised, and then inspected — adding significant cost.

Blind/Buried Vias and PCB Reliability

When done correctly, blind vs buried vias are every bit as reliable as traditional through-hole vias. However, be aware of these risks:

• Delamination: If bonding is weak, boards can delaminate under shock. Work with manufacturers adhering to IPC-6012 Class 2 or Class 3.
• Poor Plating: Connection will fail under thermal cycling if not plated properly.
• Drill Misregistration: Can lead to decreased annular ring width and opens.

FAQs

What is the difference between a blind via and a buried via?

Blind vias connect an outer layer to one or more inner layers of a PCB. Buried vias connect inner layers of a PCB only. Both blind and buried vias require sequential lamination to fabricate.

How much more do blind/buried vias cost?

Blind and buried vias can add 30–60% and 40–80% to your base PCB fabrication cost respectively. Complex boards with both can cost 5 or 6 times as much as through-hole boards.

Can I have blind and buried vias on the same board?

Absolutely. In fact, most HDI boards use a combination. Using both results in the highest number of sequential lamination steps and is the most expensive configuration.

Will blind/buried vias increase my PCB lead time?

Yes. Plan for at least an additional 3–7 working days over a traditional multilayer board due to additional lamination and plating steps.

Are microvias the same thing as blind vias?

Microvias are a type of blind via that typically connect only one layer to the next (ex. layer 1 to layer 2). They are smaller than 150 micron in diameter and are always laser drilled.

Conclusion

If your board requires high routing density, has BGAs, or stringent signal requirements, then blind and buried vias can be a huge benefit. But they do cost more money and take longer to fabricate.

Often times a well-optimised layer stackup using only through-hole vias can meet your design requirements without blowing your budget. Talk to our engineers today at PCB Company to see how we can help optimise your next multilayer PCB design.