Heavy Copper Printed Circuit Board (HPCB) 

What is a Heavy Copper PCB Board?

The heavy copper PCB is a copper PCB comprising thick dimensions in which the containment of copper in the external and internal surface is much more. The copper PCB board drives the current using tracks composed of etched copper. Therefore, the carrying capacity could improve by enhancing the width. However, it cannot be efficient every time in the copper PCB. Thus, the supplementary way to increase the capacity of current in the board is to deploy heavy copper instead of expanding the breadth of the board. In doing so, we can boost the efficiency of managing excessive heat capacity.

The resolution of current-carrying capability determined by the breadth and thickness of heavy copper ensures compatibility. Weight, plating thickness and the proper substrate utilizes to calculate copper's purity. To add copper thickness to the plated holes and sidewalls, etching and plating processes are used to create the boards. It also establishes the durability of the PCB in the through-holes, which can transform a flimsy board into one that can function as a stable wire platform. Because of this, measuring the copper's thickness whenever a circuit design is necessary to determine how many operations it can handle.

Benefits of a Heavy Copper PCB

Great thermal distribution

The copper PCB delivers high thermal mass and is utilized frequently for higher frequency and speed applications. In addition, heavy Copper PCB boasts the highest thermal resistance; consequently, it uses extensively in applications that require increased frequency and speed.

Mechanical strength

The heavy copper PCB's improved structural durability guarantees that such an electrical system will remain robust and powerful.

Good conductor

Because of their high conductivity, copper PCB boards are extensively used in semiconductors and equipment manufacturing to construct a variety of prototypes and novel systems.

Onboard heat sink

Heavy copper boards include an embedded heat sink, which enhances heat transport away from a hot device. It can do this by extending the device's operational surface area and the volume of low-temperature fluid that circulates through it.

Great heat sink

It must have been incredibly adept at employing the conduction, radiation, and convection processes.

The copper PCB may endure heat exchange from its source to the environment. It avoids overheating, assisting heavy copper PCBs.

Supports exotic material

Copper PCB board supports different bizarre materials. For example, heavy copper PCB employs in designing UPS systems, nuclear energy power plants, military models, radar systems, and solar plants. In the same way, copper PCB has a broad scope for welding devices, hydro plants, renewable energy systems, and various control systems in weapons and missiles. 

Along with that, it comprises the following subsidiary benefits.

•  It does not settle the capacity to carry the current.
• Abolishes the intricate wired bus design.
• Condensed circuit size to accommodate many copper weights on a single PCB
• Because high-temperature materials have a decreased chance of circuit failure, they can improve utilization.
• The higher current for the PCB passes through heavy copper-plated vias.
• Certain parts are plated with heavy copper to operate the built-in heat or cold sinks.
• It helps in combining high-current circuits with circuit control on a single PCB.
• Assists transfer of heat for the outer sink supplying the high-powered density.

Heavy Copper Circuit Construction

The mix of copper plating and etching methods creates the PCB whether it is double or multilayered types. Carbon PCB layers are first etched to eradicate superfluous copper before plating to provide the copper width to pads, traces, planes, and plated using holes. Typically, these copper foil sheets range in thickness from 0.5 oz/ft2 to 2 oz/ft2. Then, to create a complete package, all circuit layers are joined together utilizing an epoxy-based substrate like polyimide or FR4.

The heavy copper PCBs with substantial copper circuitry uses similar techniques, using particular methods of plating and etching, including differential etching and high-speed/step plating. In the past, copper PCB features were created by completely etching in-depth laminated clad copper material, which resulted in irregular trace walls from sides and intolerably deep undercutting. However, by combining coating and etching, it is now possible to create powerful copper features with straight sidewalls and low undercut, thanks to advancements in plating technology.

By plating a copper PCB board, the PCB manufacturer can enhance the thickness of copper in plated holes and through walls. Powerlink's advancement has enabled it to integrate copper PCBs with shared functions on a single board. Benefits include low impedance power distribution, compact designs, reduced layer counts, and potential cost reductions. The control circuits that oversee high-current/high-power circuits are often produced independently on various circuit boards. High-current circuitry and control circuits can be integrated with the copper PCB board to create a very dense yet simple board construction. The standardization of copper PCB circuits is possible by linking substantial copper components. They use the copper PCB board and their common characteristics without the restriction of negotiation from the designer and the fabricator to manufacture the tolerances and capabilities preceding the final project.

Heavy Copper PCB Capabilities

Depending on the need, making heavy copper PCBs can be pricey. As a result, while having a more complex design, it is more successful at producing heavy copper PCBs. It ought to be able to perform the following:

• Copper sheets up to 40 ounces thick ( 1400μm )
• Ceramic, Aluminum, Copper, and FR4 make up the primary material.
• Routing, punching, and V-Cutting should utilize to create the outline.
• Oil-based solder masks are available in white, black, blue, green, or red.
• Surface treatments include Immersion Gold, HASL, and OSP.
• The largest panel size allowed is 580*480mm.

Typical Applications of Heavy Copper PCB

Power converters, heat indulgence, high power distribution, and planer transformers are a few uses for heavy copper PCBs. In addition, heavy copper-clad boards are more in demand. They can utilize in industrial, military, automotive, and computer controls.

Applications for heavy copper PCB include:

• Supplying and converting powers
• Control of torque
• Solar power converters utilizing signal and safety systems
• Power distribution and monitoring of the power line
• Wielding equipment and protection relays
• Rail traction systems, UPS systems, and storage pumping plants
• Overload relays, HVAC systems, Fuse blocks, and high-power rectifiers
• Excitation systems for power regulators
• Helps in position controlling systems, military weapons control systems, nuclear power energies, and hydropower sectors.
• Line reactors and surge protectors

The heavy copper circuit boards are meeting the demand for ever-increasing power, performance, and cost requirements. This solution for a long time by PCB thermal management professionals and produces more than 20 ounces of finished copper. It also features a dependable spray coat for a protective and consistent solder mask that aids in imaging nomenclature.

Circuit Board Strength and Survivability

Circuit board producers and engineers can select from a diversity of dielectric supplies, from standard FR4 (working temp. 130°C) to excessive-temperature polyimide (working temp. 250°C). An excessive temperature or extreme surroundings may demand a striking material, but if the circuit dashes and covered vias are ordinary 1 oz/ft2, will they continue the harsh conditions? The circuit PCB industry has established a tested way of defining the thermal reliability of a completed heavy PCB board. Thermal strains generate the different fabrication of board, meeting, and reparation procedures, where the variation between the CTE of Cu, which is the coefficient of thermal expansion, and the PWB laminate supply the force of driving for growth to failure of the PCB circuit and nucleation crack. Thermal cycle testing (TCT) draughts to enhance the resistance in a circuit as it experiences 25°C to 260°C air-to-air thermal cycling temperatures.

Board Survivability

A growth in resistance denotes a breakdown in electrical integrity through breaks in the copper PCB. An ordinary coupon project for this test employs a chain of 32 coated through holes, considered the weakest point in a heavy PCB board when exposed to thermal stress. The TCT results show that the failure rate can become offensive regardless of the circuit PCB board. Therefore, the review on ordinary FR4 copper PCB boards up to 1.2-mil from 0.8-mil plating of the given copper PCB has utilized a thermal cycle. It has revealed that 32% of PCB board circuits fail after the 8th cycle, with a 20% increase in resistance that measures as a failure.

Heavy copper PCBs using exotic resources significantly enhance this disappointment rate of 3% for Cyanate Ester after the eighth cycle but are excessively expensive. It observes a minimum of 4 cycles of thermal before shipments. The assembling of an average surface-mount technology could follow two different thermal processes for repairing each component. Supplying heavy copper PCB helps in reducing or eradicating these disappointments. The failure rate could mitigate by coating 2 oz/ft2 of copper to the wall of the holes to almost 0. Consequently, the heavy copper PCB circuit turns impermeable to the mechanical stresses employed by thermal cycling.

Heavy Copper PCB Manufacturing Process

There are frequent influences on manufacturing heavy copper PCBs. But characteristically, electroplating or etching is applied. The thickness of copper is conveyed to the electroplated holes or sidewalls using the etching or plating methods. Again, though, distinctive plating and etching methods are essential to construct heavy copper PCBs. It is to guarantee that the copper is much denser than required.

When routine etching procedures often use, the manufacturing of heavy copper PCB is insufficient. The etching techniques generate only irregular, over-etched border lines. Throughout the manufacturing of heavy copper PCBs, electroplating still uses. As a consequence, the PCB's wall thickness gets increases.

There are limitations on how heavy copper PCBs manufactures, though. For example, the price of etching escalates, and a massive portion of copper gets removed. In addition, the thick copper lines enable the surface to be irregular as well. Some of the types of heavy copper PCB manufacturing include:

Techniques using the bus bar

Using this technique helps in making automobiles and other manufacturing goods. The copper PCBs are required to fit with thick copper bars to oversupply the current. As a result, a high-power circuit consuming only a few outlines can convey a superior current. In addition, the method disseminates the PCB, reducing incidentals and prices.

Embedded copper technique

This process helps produce the lay-up resin by generating a hefty copper surface by combining a heavy copper PCB with a flat interface using embedded techniques.

The heavy copper PCB thickness requirements meet through the integration of several techniques utilized in manufacturing heavy copper PCBs. No matter the double or single-sided copper PCB, both comprise the procedure of coating or plating and etching. The etching of the copper foil is the starting procedure that requires tapping the layers in a given circuit copper board. After that, the etched copper, which is unnecessary for the system, is removed. Next, different plates used are added to bulk the layers of copper in the planes, pads, and traces and coated using the holes method.

After that, the substrate made of epoxy laminates the entire circuit to finish the package. The heavy copper PCB circuits on the board enable sophisticated etching and plating procedures. Usually, thick copper-clad bonded with PCB board material carves to form the properties ultimately. As a result, there are unequal tracing sidewalls and unacceptable undercutting. As electroplating technology developed, heavy copper PCB featured plating and etching methods. It results from having smooth sidewalls and minimum undercuts. As soon as the thickness of copper increases, the quantity of copper width in plating holes through borders, and the heavy copper PCB circuit begins to build the board.

Advantages of Embedded Copper Technique

Then, a heavy copper PCB is more straightforward to blend according to the standard feature of a single circuit board. This method of manufacturing heavy copper PCBs has several advantages, along with a reduction of the number of levels, smaller footprints, low - resistance transmission lines, and significant efficiency improvements. Large current or increased-power circuits and associated control circuits generally manufacture individually for multiple boards. The reason is that thick copper coating allows the incorporation of high-current devices and controls the connections to generate a simple and concise composition of the board.

The method can insert Heavy copper PCB with minimal restriction owing to the characteristics connected to the continuous standardized circuits. It allows the developers to develop and analyze the manufacturing procedures for making it temperature-tolerant. In addition to delivering a reliable and consistent large power circuit combined with hefty base copper, one must employ electroplating and etching techniques. It enables the well-defined circuit border inside the narrow outlines and smaller intervals. Before establishing the integrated part, the whole method implements for perfect functioning.

Thermal Management

The copper PCB produces excessive heat. Since its dissipation is in the environment, it must originate from a source. The whole product may fail if the component overheats. Heat loss will reduce when using a circuit made of heavy copper. It accomplishes this by conducting heat away from crucial components in heavy copper circuits as producers attempt to gain extreme performance and value from their courses. Heavy PCB board circuits are more composite these days and used to drive to maximum density powers. Diminishment, power device utilization, thrilling situations from the surrounding, and necessities of excessive current use enhance the significance of the management of thermal entities. The extreme heat losses, which often produces utilizing the process of microelectronics, are degenerated to the surrounding by radiation from the source; otherwise, the modules cause failures due to overheating the components. However, copper PCB board circuits can support by dropping the damages created by I2R, dramatically reducing the failure rates with the heat consumption away from appreciated devices.

The interface of the heavy copper PCB uses the heatsinks to regulate temperature properly from heat sources. Any heat sink's purpose is to clear out heat with the help of conduction far from the production location and disperse this expansion into an atmospheric atmosphere by movement. Copper vias connect the heat source on one portion of the copper PCB board into the concrete bare metal substrate on the contrary direction. Typically, conventional heatsinks are welded, attached to this exposed metal substrate, or connected using a high thermal conductivity adhesive.

More on thermal system

The PCB assembly services must complete in three time-consuming and expensive processes for conventional heatsinks. This process takes a significant effort, and the outputs are not as excellent as they might be with a mechanically automated process. In contrast, built-in heatsinks are manufactured during the fabrication of a printed circuit board and do not necessitate further assembly. Techniques based on heavy copper connections enable this. 

It comprises the benefit, which includes the additional power source coat utilizing the heat vias, helping to minimize heat resistance for designing the copper PCB. It allows for the same precision and reproducibility as in PCB manufacturing. In addition, planar windings have greater average conductance than cylindrical wire conductors. It is because they consist of relatively flat conductive traces produced on copper-covered laminate. The improvement results in decreasing body effects and helps to enhance current-carrying performance.

Because of the use of a similar dielectric substance employed within the layers, by providing complete encapsulation of all field winding, onboard planners produce optimal secondary-to-secondary and primary-to-secondary isolation of dielectric separation. It utilizes to achieve inductance, mitigating the leakage. The primary windings help in subdividing the auxiliary windings sandwich between the primary. Standard PCB fusion processes can reliably sandwich up to 50 levels of coils as strong as 10 oz/ft2 employing a variety of epoxies. In addition, we generally deal with substantial plating thicknesses while fabricating heavy copper PCB circuits. Hence it allows us to determine trace detachment and pad thicknesses. For this reason, designers are encouraged to include the board manufacturer early in the planning process. The company creates a set of heavy copper PCB circuit design guidelines that would provide designers with a comprehensive overview of what is necessary.

Design Consideration and Tips

Copper width and thickness

The heavy copper PCB designers observe the amount of current needed for the design of copper boards. Any designers need to know about the consumption of required copper with a specific thickness, the temperature required, and the given width. The heat produced by the copper PCB should be proportional to the total current produced.

Choosing procedure of a proper thickness for copper PCB

The current helps in determining the proper thickness in a given conductor. Meanwhile, trace width techniques determines the copper PCB's required thickness. It defines the three different terms in a copper PCB board. They are current, temperature increment, and width of the trace. 

Current capacity

When the current flows from the trace of copper, it provides excessive heat to the copper PCB. Then the transited heat helps to gain power dissipated from the environment due to the convection and conduction method. In this way, the developer of the heavy copper PCB should calculate the current with excessive value before reaching the higher temperature of about 30 degrees Celsius in the trace. Then, a thumb rule applies in the industry in the paths exposed.

The substrate of heavy copper PCB

It is the most important term to consider by the designer during the construction of the heavy copper PCB. The material comprises a temperature of about 130 degrees Celsius utilizing the FR-4 material deploying the transition glass temperature. But due to the high current, the substrate material and transition temperature are too dangerous.

Thermal expansion coefficient

The thermal expansion coefficient increases PCB components' speed as it gets exciting. Parts per million is the expression for the coefficient. The CTE within the substrate and copper is important as thermal stress due to excessive current is generated by the traces using the cracks of the formation resulting in the copper PCB failure. The plating electrically elevates the thickness, reducing the resistance by improving heat conduction. Therefore, it reduces the resistance to heat. Due to this, radiation, convection, and conduction perform heat dissipation.

Conclusion

The heavy copper PCBs are outstanding and capable of fulfilling our electrical demands because of their extraordinary characteristics and benefits. They can support high currents and accommodate a wide range of application specifications. The usage of heavy copper circuit boards and conductive parts is crucial when producing applications like power supplies, which operate under varying heat conditions. 

They offer numerous noteworthy advantages, which is why they utilize widely in various industries. Therefore, before designing, it is critical to comprehend the strengths and restrictions of the board. Additionally, we are sure to have efficiency by using the proper manufacturing process for the copper PCB board before moving on to heavy copper PCB assembly.