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Via hole

What is the difference between a microvia and a regular via?

Microvias are smaller vias, typically with a diameter less than 150 microns, used in high-density designs. They’re ideal for HDI PCBs, where space is limited and precision is critical.

What is a microvia?
According to the new definition within IPC-T-50M a microvia is a blind structure with a maximum aspect ratio of 1:1, terminating on a target land with a total depth of no more than 0.25mm measured from the structure’s capture land foil to the target land.
What is meant by a buried via hole?

A buried via is located entirely within the inner layers of a PCB, with no exposure to the outer layers. It is used to connect two or more inner layers without affecting the outer surface.

What is meant by a blind via hole?

A blind via connects the outer layer of a PCB to one or more inner layers but does not go all the way through the board. It’s used when you need to save space and reduce signal interference.

Material

Can I mix different materials in one PCB?

Yes. Hybrid PCBs use different materials to balance cost and performance—for example, combining standard FR4 with high-frequency cores in one stack-up.

Do I have to use an FR4 material with a high Tg (Tg = glass transition temperature) for lead-free soldering?
No, not necessarily. There are many factors to be taken into account, e.g. how many layers, the thickness of the PCB and also a good understanding of the assembly process (number of soldering cycles, time above 260 degrees, etc.). Some research has shown that a material with a “standard” Tg value has even performed better than some materials with a higher Tg value. Note that even with “leaded” soldering the Tg value is exceeded.
What is of most importance is how the material behaves at temperatures above the Tg value (post Tg) so knowing the temperature profiles the board will be subjected to will help you look evaluate the necessary performance characteristics.
How many reflow cycles can FR4 materials withstand?
It is hard to give a precise answer, but we have made tests with material with up to 22 reflows, four of these with a peak temperature of 270C°. The stress after 22 reflows is considerable and material can degrade, but all connections remained functional. Our recommendation is to choose a higher grade material where there are more than 6 layers and thicker than 1.6 mm.
Which PCB surface is best for lead-free soldering?
There is no “best surface;” all surfaces have their pros and cons. Which one you should choose depends on many factors. Please consult our technicians or review the information on surface finishes within this section of the website.

FAQ about Multilayer PCBs

What should I consider when designing a multilayer PCB?

Key factors include layer stack-up, impedance control, heat dissipation, and ensuring the manufacturer can meet your specifications.

What is a multilayer PCB?
A multilayer PCB is a printed circuit board that consists of multiple layers of conductive material sandwiched between insulating layers. This type of PCB is used for complex electronic circuits that require more space for routing and component placement.
What are the advantages of using a multilayer PCB?
Some of the benefits of using a multilayer PCB include increased circuit density, improved performance, reduced electromagnetic interference, and reduced circuit size.
How are multilayer PCBs manufactured?
Multilayer PCBs are typically manufactured using a process that involves layering, drilling, etching, and laminating. The process starts with the creation of a substrate, followed by the deposition of conductive layers and insulating layers. The layers are then drilled to create vias and holes for component placement. Finally, the board is laminated to ensure stability and durability.
How does a multilayer PCB differ from a single-layer PCB?
A single-layer PCB only has one layer of conductive material, while a multilayer PCB has multiple layers of conductive material. The multiple layers in a multilayer PCB allow for more space for routing and component placement, making it possible to create more complex circuits.
What materials are used in the construction of a multilayer PCB?
The materials used in a multilayer PCB typically include a substrate material, conductive layers (such as copper), insulating layers (such as polyimide or FR4).

FAQ about HDI PCBs

Are HDI PCBs more expensive than standard PCBs?

Yes, HDI PCBs usually cost more due to complex manufacturing processes, but the benefits in performance and size often justify the higher price.

What is a HDI PCB?
IPC-2226 defines HDI as a printed circuit board with a higher wiring density per unit area than conventional printed circuit boards (PCB). They have finer lines and spaces ≤ 100 µm / 0.10 mm, smaller vias (<150 µm) and capture pads <400 µm / 0.40 mm, and higher connection pad density (>20 pads/cm2) than employed in conventional PCB technology.
How does HDI PCBs keep my cost down?
HDI PCBs help reduce costs by decreasing size, minimizing the number of components, reducing signal interference, and automating the manufacturing process.
What is the laser drill accuracy?
It is very safe to assume it is +/- 1 mil accuracy. Usually, in a staggered microvia formation, the diameters of both operate and lower microvias are the same. The key parameter that decides whether the staggering is possible or not, without the lower microvia needing to be filled, is the dimension E, the vertical separation between the central access of the two microvias. For staggering to be viable, the value of E must be greater than the microvia diameter.
Why should I turn to HDI PCBs?
At some level of circuit complexity, turning to an architecture with blind and buried vias will result in better yield and lower cost than would a through-hole design.
How do I select materials for HDI?
Materials play a large role in terms of manufacturability and direct cost of your circuit board. Here is a tip: The goal is always to select the right material for manufacturability that, at the same time, meets your temperature, and your electrical requirements. When it comes to materials, make sure that your high-speed material is also suitable for your HDI design. They are many other factors that come into play when selecting the proper materials for your design.

FAQ about High Frequency PCBs

Why do I need a high-frequency PCB for my product?

If your product needs to transmit signals fast and clearly—like in 5G, radar, or wireless devices—a high-frequency PCB helps maintain signal integrity, reduce signal loss, and ensure minimal interference.

What is a High Frequency PCB?

A High-Frequency PCB is specifically designed for applications operating at RF and microwave frequencies, typically ranging from 3 MHz to 100 GHz. These boards are engineered to support high-speed signal transmission while minimizing losses.

What makes High Frequency PCBs different from regular PCBs?

High-frequency PCBs are designed to handle RF signals, which require precise impedance control, minimal signal loss, and low interference. Unlike regular PCBs, RF PCBs are made with materials that have specific electrical and thermal properties to perform reliably at high frequencies.

What materials are used in the manufacturing of High-Frequency PCBs?

High-frequency PCBs are made using specialized laminates such as PTFE (Teflon), Rogers, and other low-loss materials. These materials are selected based on their dielectric constant, loss tangent, and thermal conductivity to ensure reliable performance at high frequencies.

Do high-frequency PCBs require special testing or handling?

Yes. They need precise manufacturing, tight tolerance control, and often stricter quality checks to ensure performance meets demanding specs.

Are high-frequency PCBs only for telecom products?

No. They’re also used in automotive radar, medical equipment, satellite systems, and any product where signal quality at high speeds is critical.

FAQ about Mixed Laminate Multilayer PCBs

What is a Mixed Laminate Multilayer PCB?
A Mixed Laminate Multilayer PCB is a type of printed circuit board that combines multiple layers of different materials in its laminate structure, providing improved electrical and mechanical performance.
What are the advantages of Mixed Laminate Multilayer PCBs?
The advantages of Mixed Laminate Multilayer PCBs include improved thermal management, increased electrical performance, reduced weight and improved dimensional stability.
How are Mixed Laminate Multilayer PCBs manufactured?
Mixed Laminate Multilayer PCBs are manufactured by laminating layers of different materials such as metal-based substrates, ceramic-based materials, and FR-4, and then drilling and plating vias to interconnect the layers.
What are the applications of Mixed Laminate Multilayer PCBs?
Mixed Laminate Multilayer PCBs are widely used in demanding applications such as telecommunications, industrial controls, medical devices, and military and aerospace systems.

FAQ about Rigid-Flex PCBs

Do rigid-flex PCBs have special quality requirements?

Yes. They need strict bend tests, good material control, and careful inspection to avoid cracks or layer separation during use.

What is a rigid-flex PCB?
A rigid-flex PCB is a type of printed circuit board that combines the benefits of rigid and flexible PCBs into one product. It consists of a rigid inner layer and a flexible outer layer, which allows for better versatility and flexibility in design and usage.
How does a rigid-flex PCB differ from a standard PCB?
A standard PCB is typically made of a single layer of material and can only bend or flex to a limited degree. A rigid-flex PCB, on the other hand, has multiple layers and can bend and flex more easily, making it ideal for applications that require a lot of movement or compact design.
What are the benefits of using a rigid-flex PCB?
Rigid-flex PCBs offer improved durability, reduced space requirements, and better electrical performance compared to standard PCBs. They are also better suited for harsh environmental conditions, such as extreme temperatures, shock and vibration.
What industries commonly use rigid-flex PCBs?
Rigid-flex PCBs are widely used in the aerospace, medical and telecommunications industries, among others.
What is the production process for a rigid-flex PCB like?
The production process for a rigid-flex PCB is similar to that of a standard PCB, but with additional steps to create the flexible and rigid layers. The flexible layer is typically made from a polyimide material, while the rigid layer is made from a traditional PCB material, such as FR4. The two layers are then combined and laminated together to create the final product.

FAQ about Flexible PCBs

What should I know before ordering flexible PCBs?

Good design is key. Clear bend areas, proper materials, and choosing a supplier with flex PCB experience help avoid cracks or breaks.

What is a flexible PCB?
Flexible PCB is a type of circuit board that is made of a flexible material, such as polyimide or polyester, instead of traditional rigid FR-4 material. It allows for greater design freedom and can be bent, folded, and curved to fit into tight spaces.
What are the benefits of using flexible PCBs?
Flexible PCBs have many benefits, including increased design flexibility, reduced weight and size, increased reliability, improved performance, and cost savings compared to traditional rigid PCBs.
What types of applications are suitable for flexible PCBs?
Flexible PCBs are widely used in many applications, including mobile devices, wearable technology, medical devices, and automotive electronics.
What materials are used to make flexible PCBs?
Flexible PCBs are typically made from polyimide or polyester, which are flexible and have good thermal and electrical performance. Other materials, such as polycarbonate, may also be used depending on the specific requirements of the application.
What is the difference between flexible and rigid-flex PCBs?
Flexible PCBs are made entirely of a flexible material, while rigid-flex PCBs are a combination of flexible and rigid PCBs. Rigid-flex PCBs are used in applications where a combination of flexibility and rigidity is required, and they offer the benefits of both flexible and rigid PCBs.

FAQ about Double sided PCBs

What is a double sided PCB?
Double sided PCB, also known as double sided printed circuit board, is a type of circuit board that has conductive pathways and components on both sides of the board.
What is the process of manufacturing double sided PCBs?
Double sided PCBs offer several advantages including increased component density, improved signal integrity, and reduced size and weight of the final product.
What are the advantages of double sided PCBs?
The process of manufacturing double sided PCBs main involves drilling, plating, etching, lamination, and testing etc.
How does the trace routing differ in double sided PCBs compared to single sided PCBs?
In double sided PCBs, trace routing can be done on both sides of the board, allowing for a more flexible and efficient design. In single sided PCBs, trace routing is limited to one side only.

FAQ about Thick copper PCB

What quality issues should I watch for with thick copper PCBs?

Pay attention to trace width, layer adhesion, and heat management. Work with an experienced manufacturer to avoid defects like uneven plating.

What is considered a thick copper PCB?
A thick copper PCB typically refers to boards with copper thickness of 2 oz (70μm) or more per layer. SprintPCB can manufacture up to 6 oz copper for heavy-duty applications.
What are the main applications of thick copper PCBs?
Thick copper PCBs are widely used in power supply modules, automotive electronics, renewable energy systems, industrial control, and high-power converters, where high current and efficient heat dissipation are essential.
What are the advantages of thick copper PCBs?
They offer high current-carrying capacity, improved heat dissipation, mechanical strength, and extended product life in demanding environments.
Can SprintPCB produce multilayer thick copper PCBs?
Yes. SprintPCB supports multilayer thick copper PCBs, combining heavy copper with advanced lamination techniques to ensure signal integrity and thermal management in complex designs.
Are there any design guidelines for thick copper PCBs?
Yes. Due to the increased copper thickness, trace width, spacing, and via plating need to be carefully designed. Our engineering team provides DFM (Design for Manufacturability) support to help you optimize your layout for thick copper requirements.

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