Reliability of High Density Interconnect
In today’s world of technology, there is a strong demand for advanced components to be placed in smaller devices. This push for smaller products has created the need for higher density interconnect, allowing more workings to be packed into a compact PCB. As the industry shifts towards HDI, it is important that manufacturers know how to test and qualify this technology to ensure the reliability of their finished products.
The complexity and tight size constraints posed by high density interconnect technology require careful attention to detail throughout the design process. This includes meticulous consideration of component placement, signal integrity, power distribution and thermal management. Adding to these challenges is the fact that HDI circuit boards are built using a different manufacturing process than PTH (plated through hole) PCBs. This involves microvia drilling and sequential lamination, a method which requires the layering of thin sheets of insulating material and conductive copper foil to build up the circuit board’s structure.
While these complexities may not be apparent when viewing the finished product, they become more prominent during manufacturing and assembly. As the manufacturing process moves forward, engineers must be aware that any change in a component or layout can lead to performance issues. This is particularly true for high-speed digital signals, which can be significantly impacted by changes in signal and power routing.
How to Test the Reliability of High Density Interconnect
A key aspect of this process is ensuring the proper selection of materials for use in HDI circuit boards. This is because the increased capabilities of HDI PCBs can put them at risk for reliability issues if the wrong materials are used. For example, the fine line widths and spacing, via pad sizes and drill diameters of HDI PCBs can have an impact on signal and power integrity at high speeds.
Fortunately, there are many standards documents available for PCBs that have been developed to address these concerns. These include IPC, MIL-STD, SAE, NASA/DO and other standard specifications for specific products and industries. These standard tests can be used as a guide when performing a comprehensive testing program for your HDI PCBs to ensure that they meet all the requirements of your application.
To further protect the reliability of HDI printed circuit boards, manufacturers should always work with a reliable supplier who is familiar with the intricacies of this technology and can offer expert guidance on how to design for optimal performance. A quality fabrication house will also be able to recommend the right materials and processes for your particular needs, which will help to ensure that you get the most out of your HDI circuit boards.
HDI printed circuit boards are a powerful tool for electronic designers looking to maximize the functionality of their products without sacrificing space. They offer ultra-low losses, dielectric constants that rival ceramics and a peel strength that is superior to conventional through-hole designs. The benefits of HDI PCBs are clear, bringing greater performance to the devices that we depend on every day.