Why are the costs of high-level HDI boards relatively high? What are the factors influencing the quotations?

In the PCB industry, high-end HDI boards have always been regarded as products with a high technical threshold and significant manufacturing difficulties. When many customers inquire about prices, they often find that for the same size circuit board, the price of high-end HDI boards is usually several times or even more than that of ordinary PCBs. Especially in the fields of smart phones, automotive electronics, medical equipment, and communication devices, the purchase cost of high-end HDI boards typically accounts for a significant portion of the overall electronic material cost of the entire device.

So, why are high-end HDI boards more expensive? How are the quotations determined? Which factors will directly affect the final cost? This article will conduct an analysis from multiple dimensions such as materials, processes, equipment, yield rate, and market demand.

Why are high-end HDI boards more expensive than ordinary PCBs?

The common PCB mainly adopts mechanical drilling and conventional circuit fabrication techniques. The production process is relatively mature, with lower equipment investment and production costs.

And high-level HDI boards usually involve:

Laser micro-hole processing

Repeated pressing

Blind-buried hole structure

Any-layer interconnection

Ultra-fine circuitry technology

High-precision impedance control

These technical requirements not only increase the manufacturing process, but also raise the investment in equipment and the difficulty of production management.

In simple terms, the reason why high-end HDI boards are expensive is not due to the material itself, but rather the combined increase in costs resulting from "manufacturing difficulty" and "yield control".

What are the main factors influencing the pricing of high-end HDI boards?

1. HDI Level

This is one of the most direct factors influencing the price.

Common classifications include:

First-order HDI

Second-order HDI

Third-order HDI

Fourth-order HDI

Any-layer HDI

The higher the order:

The more times the laser is used for drilling, the better.

The more times of pressing and bonding there are

The greater the difficulty of the position, the more challenging it is.

For example:

The first-generation HDI may only require one layer stack-up and bonding process.

And the third-order HDI usually requires more than three lamination processes and multiple rounds of laser drilling.

The complexity of the process has increased exponentially.

Therefore, the price will also increase significantly.

II. Number of Layers

The number of layers is an important component of the quotation.

Common products include:

8-layer HDI

10-layer HDI

12-layer HDI

16-layer HDI

HDI above the 20th floor

An increase in the number of layers means:

More circuit boards and semi-cured sheets

More complex layering structure

A longer production cycle

For example:

Compared with the 8-layer board, the manufacturing cost of the 16-layer board usually does not simply double, but may increase by several times.

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III. Types of Panels

The prices of different materials vary significantly.

Common FR-4 material

The cost is lower.

Suitable for general electronic products.

High TG material

It has better heat resistance.

Suitable for automotive electronics and industrial equipment.

High-frequency and high-speed materials

For example:

Rogers Series

Panasonic series

Megtron series

For:

5G Communication

AI server

High-speed switch

The prices of these materials are much higher than those of ordinary FR-4.

Sometimes the cost of a single material alone can account for more than 30% of the total cost of a board.

IV. Number of Laser Micro-Holes

High-end HDI boards extensively use laser drilling.

Common aperture:

100 micrometers

75 micrometers

60 micrometers

The smaller the aperture is:

The processing time is longer.

If a board has several hundred thousand tiny holes:

The cost of laser drilling will increase significantly.

Therefore, many manufacturers will focus on calculating the following when making quotations:

Number of micropores

Pore density

Drilling time

V. Line Precision Requirements

The thinner the wire is, the greater the processing difficulty will be.

For example:

Standard PCB:

4mil/4mil

5mil/5mil

Advanced HDI:

3mil/3mil

2mil/2mil

1.5 mil / 1.5 mil

Ultra-thin circuits require:

LDI Laser Imaging

mSAP process

SAP process

These advanced techniques will significantly increase the production costs.

VI. Impedance Control Requirements

High-speed electronic products usually require strict control of impedance.

For example:

50Ω single-ended impedance

90Ω differential impedance

100Ω differential impedance

Control accuracy requirements:

±10%

±5%

Even ±3%

The higher the precision requirement is:

The higher the cost of inspection and adjustment during the manufacturing process.

VII. Copper Thickness Requirements

The thickness of copper directly affects the cost of materials and processes.

Common specifications:

0.5 ounces

1oz

2oz

3oz

The thicker the copper layer:

The longer the electroplating time is

The greater the difficulty of etching

For automotive electronics and industrial equipment, thick copper design is very common.

The cost has naturally increased.

VIII. Surface Treatment Process

There is a significant price difference among different surface treatment methods.

Spray tin (HASL)

The cost is lower.

Silver Inlay (ENIG)

It is widely applied.

The surface is relatively flat.

Chemical nickel palladium gold (ENEPIG)

Suitable for high-reliability products.

Electroplated gold

Commonly found on high-end connector boards.

The cost is the highest.

Therefore, the surface treatment process will directly affect the quotation.

Why does yield affect costs?

Many customers only focus on the materials and craftsmanship, but overlook the factor of yield rate.

In fact:

A significant portion of the cost of high-end HDI boards comes from yield losses.

The more complex the process is, the higher the risk of scrapping.

During the high-level HDI production process, the following situations may occur:

Alignment deviation of holes

Fill in the holes and cavities

Interlayer misalignment

Line breakage

Impedance out of tolerance

If there is any problem at any stage:

The entire board may be scrapped.

A decline in yield will increase the unit cost.

For example:

Produce 100 pieces of boards.

If the yield rate is 95%, only 5 pieces will be lost.

If the yield rate is 80%, then 20 pieces will be lost.

These losses will eventually be passed on to the product prices.

Therefore:

High-end HDI boards are not merely for selling products.

It is even selling manufacturing capabilities and maintaining stable production rates.

Why does the investment in equipment get reflected in the price?

Advanced HDI manufacturing relies on a large number of high-end equipment.

Mainly includes:

Laser drilling machine

Used for micro-hole processing.

The value of a single device is usually quite high.

LDI exposure equipment

Realize the fabrication of ultra-thin circuits.

It belongs to the high-precision core equipment.

Vacuum Pressing Machine

Used for multiple layer lamination.

AOI automatic inspection equipment

Improve product yield.

X-ray detection equipment

Detect internal structural defects.

These equipment require huge investment, and also involve costs for maintenance, calibration and technological upgrades.

It will all be reflected in the product quotations in the end.

Why is there such a big difference in price between small-batch and large-batch production?

This is a problem that many customers tend to overlook.

Small batch production

Feature:

The proportion of engineering costs is high.

Long machine adjustment time

Low material utilization rate

The unit cost is relatively high.

Mass production

Feature:

Engineering cost amortization

Improvement in material utilization rate

The yield is more stable.

The unit cost has significantly decreased.

Therefore:

The same high-end HDI board,

The unit price of 10 sample boards and 10,000 production boards may differ by several times.

How to reasonably control the procurement cost of high-end HDI boards?

Enterprises can optimize from the design stage.

For example:

Avoid excessive design

Not all products require fourth-order or any layer HDI.

Optimize the layer structure

Properly plan the layered design.

Control the number of micropores

Reduce unnecessary laser holes.

Select the appropriate type of board

Select materials based on the actual performance requirements.

Conduct DFM review in advance

Reduce production risks through manufacturability analysis.