Skip to main content

Double-Sided PCB Assembly and Manufacturing Processes

Published Date
Author Cadence PCB Solutions

Key Takeaways

  • Double-sided PCBs are used in house appliances, mobile phones, computers, lighting systems, amplifiers, and vending machines. 

  • The double-sided PCB manufacturing process is different from the single-sided PCB manufacturing process. 

  • In double-sided PCB assembly, wave soldering is impractical, as the resubmission of the board for soldering for the second time ruins the delicate parts on the first side. 

  PCB assembly and manufacturing

As the name suggests, a double-sided PCB utilizes both sides of the printed circuit board. Unlike single-sided boards, double-sided PCB assembly includes components on both sides of the PCB. Double-sided PCB assembly and manufacturing processes are different from the processes for single-sided PCBs. Double-sided PCBs are often used in higher technology electronics due to their reduced size and cost as well as their flexibility and density. Let’s explore the manufacturing and assembly process for these PCBs.

Single-Sided vs. Double-Sided PCBs

PCB technology is valuable for building electronic circuits and devices. The PCBs that connect electronic components are an inevitable part of any electronic design. Single-sided PCBs are the most common type of PCB and are also the easiest to fabricate and assemble. In single-sided PCBs, components are assembled only on one side of the board. The conductive wiring on the bottom surface connects the components placed on the top surface.

Technological developments required more from the circuit boards incorporated in advanced electronic devices and equipment; to meet these demands, double-sided PCBs were developed. 

Introducing Double-Sided PCBs

Double-sided PCBs are different from single-sided PCBs, with traces routed on both the top and bottom layers of the PCB. Double-sided PCBs mount components on both sides of the circuit board and permit the crossing of traces. For higher density, complex circuit fabrication, double-sided PCB technology is the best option.

Double-sided PCBs are used in house appliances, mobile phones, computers, lighting systems, amplifiers, and vending machines. They are suitable for mass production of fixed circuits and bring a greater level of optimization to electronic equipment layout.

There are many benefits to using double-sided PCBs; let’s discuss some of their advantages next. 

Advantages of Double-Sided PCBs

  • An extra layer for assembling components, increasing the density of the board. 

  • Extra space improves the flexibility of the PCB and can be employed to build complex circuits.

  • Board size reduction; compact sizing leads to reduced costs during the PCB fabrication and assembly process. 

  • High performance at extreme temperatures and under humid atmospheric conditions. 

  • High reliability and safety due to their open structure.

  • Longer life expectancy than single-sided PCBs. 

Double-Sided PCB Assembly and Manufacturing Processes

On a double-sided PCB, there is a copper coating on both sides. In between this coating, the insulating layer is positioned. Proper circuit connection between both sides is ensured with vias. Finally, components are placed on either side of the double-sided PCB. 

Manufacturing 

The double-sided PCB manufacturing process involves the following steps in the given order:

Preparing material→cutting copper-clad laminate→drilling→deburring→electroless copper deposition or plating through holes→photo imaging→pattern plating→etching→solder masking→surface finishing→gold and nickel plating→applying silkscreen→separation or cutting→electrical testing

Double-sided PCB manufacturing can be completed in two ways:

  1. Dry run process - PCB assembly is completed in one pass through a press.

  2. Wet run process - PCB assembly is completed with a pre-assembled die on both sides.

Assembly 

If a PCB is double-sided, then the soldering process is required for both sides. Whatever happens on the top side applies to the bottom side as well. The difference in the flipside component assembly for double-sided PCBs is that the melting point of the solder mask should be a bit lower than the one used on the other side. In case the components are smaller than the other side’s assembly, the component placement needs extra attention. In double-sided PCB assembly, wave soldering is impractical, as the resubmission of the board for soldering for the second time ruins the delicate parts on the first side. 

Here is how double-sided PCB assembly is performed:

First, the components on one side are assembled and soldered. Then, the board is flipped for assembly on the other side. The step-by-step process can be described as follows: 

Apply solder paste→pick and place components→solder components→review the assembly→test→flip the board→apply solder paste→pick and place the components→solder the components→review the assembly→test

The volume of double-sided PCB assembly and manufacturing processes handled by PCB manufacturers is increasing as the electronics market demands more high-density compact designs for complex circuits. Designers can rely on Cadence software to design double-sided PCBs. OrCAD software offers tools and features that support double-sided PCB designs.

Leading electronics providers rely on Cadence products to optimize power, space, and energy needs for a wide variety of market applications. If you’re looking to learn more about our innovative solutions, talk to our team of experts or subscribe to our YouTube channel.