All you need to know about Blind and Buried Vias PCB!

By | Date posted: | Last updated: May 6, 2022
Blind and Buried Vias PCB

When it comes to high density PCBs where you cannot fit all your connections on one layer, vias are extremely useful.

Simply put, vias are barrel shaped vertical conductive holes that help make connections between multiple layers of a PCB.

Blind and buried vias

The two vias are popular when you need to make connections between the multiple layers of a printed circuit board that are blind and buried vias.

To put it succinctly, a blind via connects the outermost layer of the board to one or more inner layers, but does not go through the whole PCB. Blind vias free up space and works well for fine pitch BGA components. They also help reduce signal stubs through the drilling process as the via terminates at the last connected layer.

A buried via, on the other hand connects two or more inner layers but doesn’t penetrate through to the outer layer. As their name suggests, they are hidden beneath the layers and free up surface space without impacting the traces or surface components on the top or bottom layers.

Both blind and buried vias are of tremendous use in High density interconnect PCBs. Such PCBs offer multiple advantages including but not limited to:

  • High layer density
  • Better power delivery
  • Ability to use smaller pitch devices

Types of blind vias

There are broadly four types of blind vias

  • Photo defined blind vias.
  • Sequential lamination blind vias.
  • Controlled depth blind vias.
  • Laser drilled blind vias.

Photo Defined Blind Via

This is created by laminating a sheet of photosensitive resin to a core. The layer of photosensitive material is covered with a pattern that covers the areas where the holes are to be created. It is then exposed to light that causes the material on the PCB to harden. After this, the PCB is immersed in an etching solution. Post the etching process the copper is plated in the hole and on the outer surface. These vias are typically used to create BGA packages.

Sequential Lamination Blind Via

This is created by processing a thin piece of laminate. The laminate is drilled, plated and etched. The other side is left as a solid sheet of copper. The subassembly is then laminated. The combined lamination is processed to create the outer layers of a multilayer PCB. This process needs some extra steps, hence the price of this kind of via is high. Additionally, there is also yield loss that comes with handling thin laminates.

Controlled Depth Drilled Blind Vias

These are created like through-hole vias. The drill penetrates only someway through the PCB. Care is taken to see that no features below the drilled hole come in contact with the drilled hole. Copper is hen plated in the drilled hole and the through-hole vias. These vias are least expensive. However they come with a limitation that the holes must be large enough for the mechanical drills to create them and the area below them must be kept clear of circuits.

Laser Drilled Blind Vias

These are created once all the layers in the PCB are laminated and before the outer layer is plated and etched. With the use of either CO₂ laser or Eximer laser the copper on the outer layer is ablated.

The CO₂ laser is extremely powerful and can quickly drill the holes. However, with this laser the drilling step has to preceded by an etching step. The eximer laser can drill through both the copper balance in PCB and the underlying dielectric material to form a blind via.

The Advantages of Blind Vias

Blind vias help to reduce parasitic capacitance. This is done by shortening the length of the vias and by reducing their diameters. Blind vias are therefore a great way to connect signal lines operating above 4.8 Gb/s.

Some of the limitations of blind vias include:

  • A blind via is a blind hole in the PCB. In order to ensure that the plating is done correctly, the diameter of the hole should be equal to its depth. This requires an aspect ratio of 1:1 or less. Some fabricators require a diameter that is 1.5 times the depth.
  • With a blind via the drilling needs to stop at the intended layer. With a laser drill, while the drill needs to go through copper on layer 1 in should not drill the copper connecting pad that is in layer 2. This requires careful calibration.
  • Another issue is to do with soldering a component to a pad into which the blind via is placed. When solder paste is applied to the pads, the air in the blind via is trapped under the hole that cannot weaken the joint.

Aspects to keep in mind in making vias

Vias can be made before or after multilayer lamination. One or more cores are drilled and through holes are plated. The stack is then built and pressed.

In creating blind vias, it is important to be aware of the drill depth. If the hole is too deep it can impact the integrity of the signal and if the hole is too shallow the connection wouldn’t be proper.

It is also important to plug the vias with either metal or thermal/electrical epoxy and plate it with copper. In the absence of this, bubbles can move upwards and impact the solder joint.

The other aspect to keep in mind is that the vias must cut through an even number of copper layers. Also, if the via is completely enclosed within the terminal point it can lead to a significant increase in costs.

While discussing Blind & Buried Vias it is also important to understand what stacked & microvias are:

A stacked via further helps in improving the size & density considerations of the PCB. It therefore greatly aids miniaturization and high-signal transmission speed.

If you have blind vias with an aspect ratio of greater than 1:1 or if your drilling needs span multiple layers, a stacked via is needed. These are laminated blind or buried vias. Not only do stacked vias save space and help in high-density, they also offer greater flexibility when it comes to the inner connections along with better routing capacity and less parasitic capacitance.

A microvia is a small via that offers more routing space on the board and lower parasitic capacitance. However, such Vias requires more drilling time.

To sum up

The main benefits that blind and buried vias offer, include:

  • You can meet the density requirements and constraints for lines and pads on your design without increasing the overall layer count or the size of your board.
  • They help in saving space and meeting extremely tight design tolerances.
  • They help designers manage the hole-to-pad ratio and restrict chances of breakout.

The issue with blind and buried vias include:

  • They increase the cost of the board. This is because the board is complex and many manufacturing steps are added. Also testing and precision checks need to be added. Between the two, however, buried vias offer a lower cost.

It is important to choose the right electronic contract manufacturing partner who has the requisite experience with blind and buried vias.

Technotronix is one of the leading PCB manufacturers based in the USA. We have adopted advanced methods and technologies, which can give you the finest PCB manufacturing services. Our ability to deliver, unparalleled quality as well as customer service, is what makes us stand out. Both on-time delivery and price competitive products are our USP. The most important element of our success, however, has been the relationships we have developed with our customers.

In case if you have any questions, please feel free to contact us via email at [email protected] or call us at 714/630-9200.

Ceramic Multilayer PCB – Top Advantages and Disadvantages!

By | Date posted: | Last updated: April 26, 2022
Ceramic Multilayer PCB

The success of a PCB has a lot to do with the selection of the board material. While FR4 is often used as a default option, the fact remains that there are a number of alternatives that offer better performance and maybe lower costs. Let us look at some of the advantages and disadvantages of a relatively modern technology – ceramic multilayer PCB – that is increasingly gaining ground.

Ceramic Multilayer PCBs

With miniaturization of devices becoming the norm, the PCB industry has been focusing on miniaturization of traditional substrate and laminate PCB materials as well as increased layers. However there have always been challenges around issues such as:

  • Heat dissipation
  • Removal of excesses from the board, and more.

The above has necessitated the search for materials that would work well given the challenges. In many ways ceramic PCBs have been a strong answer. Ceramic materials such as aluminum oxide, aluminum nitride, beryllium oxide and more are seen to perform well on parameters such as:

  • Thermal conductivity
  • Resistance to erosion
  • CTE component compatibility
  • High density trace routing, and more

Advantages of Ceramic Printed Circuit Boards

Before we look at the advantages of ceramic boards in detail, it is important to mention that ceramic isn’t a single material but a class of materials with similar physical and chemical properties.

Thermal Conductivity

A big advantage with ceramic material is its high thermal conductivity. In fact, as compare to ceramic, FR4 has extremely low thermal conductivity. Some figures will put this in perspective:

  • Aluminum Oxide is 20 times as thermally conductive as FR4.
  • Aluminum Nitride and Silicon Carbide are about 100 times as thermally conductive as FR4.
  • Boron Nitride is known to have the highest thermal conductivity.

In case of FR4 PCBs the low thermal conductivity is compensated by using elements such as:

  • Thermal Vias
  • Metal Planes
  • Fans
  • Thermal Landings, and more to direct heat away from the surface layers.

Ceramic boards, on account of their high thermal conductivity, usually do not require these elements as heat can easily be transported to a thermal landing or an active cooling element.

Additionally, the high thermal conductivity ensures that there isn’t any formation of hot spots in the surface as well as the inner circuit layers as heat transport is uniform.

Low Electrical Conductivity

Despite being high on thermal conductivity, the electrical conductivity of ceramics is still low enough for it to be used for PCB substrates. Additionally, it is also possible to adjust the electrical conductivity of ceramic boards through doping.

Do not exert stress on vias

Another advantage of using ceramic boards is that they do not tend to exert a large amount of stress on any vias leading to their fracture. Vias in FR4 boards, particularly are susceptible to fracture during thermal cycling. The risk of fracture is on account of the fact that there are mismatches in the thermal expansion coefficient of copper and FR4. Thermal cycling of the boards, therefore, creates stress along the via barrel and is prone to fractures. In the case of ceramic circuit boards, their thermal expansion coefficients are closer to the values for their conductor structures. This reduces stress during thermal cycling. Also, with the thermal expansion being uniform the stress son any via is significantly reduced.

Mechanical Strength

The big advantage with ceramics is also its mechanical strength. Its ability to withstand high mechanical load as well as strong vibrations and shock can go a long way in their use in harsh operating environments. This is made possible because a ceramic board has a lower Young’s Modulus as opposed to FR4. The ceramic board, therefore, tends to deform much less as opposed to an FR4 board when the same pressure is applied.

Some of the other pros of using ceramic boards include:

  • They resist chemical erosion.
  • Have compatible mechanical intensity.
  • Easy high-density tracing implementation.

This does not, however, mean that ceramic boards come with any disadvantages. The main disadvantages associated with ceramic boards include:

  • They have a higher cost than standard PCBs.
  • They aren’t as widely available.
  • They entail careful handling.

It is important, therefore, to go over the features required by you carefully, in making the right choice of printed circuit boards.

At Technotronix, our highly qualified and experienced multilayer PCB manufacturer ensures that all the layers are correctly registered. Adhering to high-quality multilayer PCB manufacturing practices, we are equipped to handle complex boards with up to 24 layers, which are laminated to insulate them. If you are looking for progressive ceramic multilayer PCBs, you are at the right place.

In case if you have any questions, please feel free to contact us via email at [email protected] or call us on 714/630-9200.

Top benefits of Automation in Electronics Manufacturing!

By | Date posted: | Last updated: April 19, 2022
Automation in Electronics Manufacturing

Industrial automation refers to using technology and control systems to replace physical labor in manufacturing. It is clearly a step ahead of mechanization. In fact, with a combination of mechanics, hydraulics, pneumatics, tasks that were carried out by human beings can be automated. This, in turn, will pave the wave for Industry 4.0, that will revolutionize manufacturing as well as engineering.

In fact, industrial automation will positively impact a wide variety of sectors, right from automotive to FMCG.

The benefits of automation in electronics manufacturing:

1. Improved efficiency

One of the biggest advantages that accrue from automation is that it takes away the propensity of error that comes with manual intervention. Even though machines may not be a match to human creativity, they are great to get repetitive work done without fatigue and therefore, errors.

In electronics manufacturing, particularly in manufacturing mission critical equipment where accuracy is key, the importance of automation cannot be overstated. Also, where the work takes place in dangerous environs or where the work is extremely monotonous, automation offers the right solution.

2. Reduced Costs

In terms of costs, automation goes a long way in saving labor costs. In fact machines can work for far longer hours even in extreme conditions. Not just that, if you do not implement automation solutions, this cost will continue to rise. In fact, in the wake of the pandemic labor shortage has only worsened that can make businesses extremely unviable.

3. Safety

With robots and automated machines being able to handle dangerous tasks and harsh environmental conditions, it ensures safety. Be it lifting heavy equipment or inclement weather conditions, you do not have to worry if you are using automation, as opposed to using manpower.

4. Improved quality

The improved quality from automation also occurs on account of the fact that when machines take over repetitive, monotonous work, it frees up time for people to focus on innovation and other complexities. What this results in, is overall high quality products. In fact, with the basic tasks being taken care of by machines, human beings can focus on high value activities bringing progressive improvement in the quality of electronics.

5. Quick time-to-market

Automation in electronics manufacturing services leads to faster production, and in turn quick time-to-market, which is a big source of competitive advantage. In fact, with appropriate preventive maintenance, machines can run nearly perpetually.

6. Improved Customization

With automation allowing manufacturers to increase flexibility in production, what will also benefit is the ability to customize products to different specifications. Traditionally, electronic products have been built in high volumes to the same specification. With smart factories, this is slated to change.

With this improved level of flexibility, what will also see a change, is the ability of original equipment manufacturers to build prototypes and hence new products quickly.

7. New products

Automation is certainly going to result in a wide range of new products introduction (NPI) that will improve lives as also drive automation even further forward paving the way for high quality products that push boundaries.

8. Improved Sustainability

Automation can lead to streamlining overall operations as well as reducing resource costs. Importantly, it also leads to reducing the company’s environmental footprint. In fact compared to legacy systems automation uses fewer resources as well as less energy. It therefore has lower emissions.

Customers too prefer eco-friendly brands and prefer companies that source material ethically and impact the surrounding environment and communities positively. In fact, the entire supply chain benefits from eco-friendly practices including the many vendors and suppliers who can also claim that everything was sourced and supplied using sustainable means.

To sum up

At the onset the key factors that led to industrial automation were improving productivity and cutting costs. The focus, however, is moving towards improving quality and nimbleness and agility.

In fact, the adoption of automation will lead more and more electronic manufacturers to use efficient operations. Any challenges along the way will involve their mitigation using remote monitoring as well as smart control systems. The eventual future definitely is lights-out manufacturing, with several organizations already adopting the concept.

As a leading electronics contract manufacturer, Technotronix offer PCB manufacturing service with combining state-of-the-art technology and advanced engineering to deliver unparalleled quality and service. We are upgrading ourselves every day and offering the finest circuit board assembly, circuit board designs and fabrication services to our clients.
If you have questions or queries related to any kind of PCB manufacturing services, email us at [email protected] or call us on 714/630-9200.

High TG PCB Manufacturing: Characteristics, Applications & Advantages!

By | Date posted: | Last updated: April 12, 2022
High TG PCB Manufacturing

The demand for high Tg PCB manufacturing has been seeing exponential growth. Not without reason, High Tg PCB offers high resistance to temperature, pressure, moisture, harmful chemicals and more. They also offer increased electrical and mechanical support to devices. Little surprise then that high Tg PCBs find application in a wide variety of applications.

Let us look at the concept of high Tg PCB in detail:

What is a high Tg PCB?

Tg or Transition Glass temperature is the highest temperature at which a substance remains in a solid state. Beyond this temperature, it changes into its liquid form. A high Tg PCB therefore is designed to withstand extreme temperatures. Such PCBs work well in harsh temperature conditions as they do not melt or soften. If the operating temperature exceeds TG, the PCB can melt, show deformation, and more.

Standard PCBs offer a Tg value of 140°C, which can withstand an operating temperate of 110°C. For industries such as automotive, aeronautics and more, that have extreme temperature processes, a PCB made of FR-4 can offer a workable solution.

What is FR-4?

FR-4 is a flame-retardant fiberglass reinforced epoxy material. It offers far greater heat resistance than standard PCBs. FR-4 circuits boards, in turn, are classified based on the number of copper trace layers, as below:

  • Single-sided PCB / Single-layer PCB
  • Double-sided PCB / Double-layer PCB
  • Four or more than 10 layers PCB / Multilayer PCB

What happens when the temperature exceeds the Tg value for the PCB?

When the temperature of the PCB exceeds its Tg value, the substrate undergoes structural change and changes into a rubbery state. This impacts the mechanical and electrical properties of the PCB.

When do you require a high temperature circuit board?

A high temperature circuit board is required when:

  • Your product operates at 130 degrees Celsius or even higher.
  • You have made a transition to RoHS circuit boards that requires high temperature for lead free solder.
  • High Tg PCBs dissipate heat in the following 3 ways:
  • Conduction – This is achieved by placing the heat sink directly with the heat source.
  • Radiation – Here the heat dissipates by creating a direct path for electromagnetic waves.
  • Convection – The heat dissipates by moving it to water or air.

Properties of High Tg Printed Circuit Boards

Some properties of a high Tg PCB include:

  • Ability to withstand high temperature.
  • Ability to withstand pressure.
  • Improved mechanical and electrical properties.
  • Low coefficient of thermal expansion.
  • Improved durability.

On account of the above properties, even if a high Tg PCB comes at a higher cost, it still turns out to be a cost-effective solution for high-energy applications.

Advantages of high Tg PCB manufacturing

The advantages of high Tg PCB include:

High stability and durability

With a high Tg PCB you are assured of high durability as it can withstand high temperature, pressure, moisture, harmful chemicals and more.

Suited for high power density designs

When it comes to high-power density designs a high Tg PCB is ideal as it withstands high temperatures.

Suited for multilayer PCBs

A High Tg PCB comes in handy for multilayer PCBs that are the need of the hour for sophisticated appliances. With their ability to function under harsh conditions, they go a long way in improving the reliability of the appliance.

Applications of High Tg PCB Manufacturing

Any electronic application where excessive heat is a norm, benefits from a high Tg PCB. High Tg PCBs are also the perfect answer to high power PCB designs. Some of the areas where they find extensive application include:

Industrial Applications

Whether it is drilling machines, power inverters, solar power equipment or other devices, high Tg PCBs find extensive use in industrial applications.

Automobile Industry

The automobile industry finds wide use of high Tg PCBs. They find application in:

  • Radar technology
  • Control systems
  • Navigation devices, and more

Some of the other industries where high Tg PCBs are extensively used include:

  • Computer Technology
  • Telecommunication appliances
  • Security systems
  • Wi Fi Boosters
  • High Processing antennas
  • Medical appliances
  • Aeronautical appliances, and more

To Sum Up

With the development of high Tg PCBs, the focus has clearly moved from trying to minimize heat generation in appliances to resisting the heat efficiently.

At Technotronix, we specialize in high Tg PCB manufacturing which finds an extensive application in a wide range of industries that operate at relatively high temperatures. With over 4 decades of experience in PCB manufacturing as well as assembling PCBs with differing levels of complexities, we follow industry best practices to ensure we deliver cutting-edge products.

In case you have any questions regarding high temperature PCB, please feel free to contact us via email at [email protected] or call us on 714/630-9200.