As electronic devices continue to evolve, more advanced PCB (Printed Circuit Board) designs require packing more functionality into smaller spaces. These designs typically use custom integrated circuits (ICs) or systems-on-a-chip (SoCs), featuring a higher number of layers and finer trace widths. To ensure the correctness and performance of these designs, powerful rule-driven design tools are required. These tools check the routing and layout against design rules to ensure that the circuit board functions as intended.<\/p>\n
In this article, we will take an in-depth look at the key design rules that need to be established when preparing an HDI (High-Density Interconnect) PCB layout, as well as some tips for improving efficiency. Although we will use Altium Designer as an example, these rules generally apply to any PCB design platform.<\/p>\n
HDI PCBs are not significantly different from standard PCBs in many respects, except for their high component and trace density. HDI PCBs are typically defined as boards with 10 million or fewer vias, 6 million or fewer traces, or a pin pitch of 0.5 millimeters or less. Generally, these PCBs use blind vias of approximately 8 mils or smaller, with the smaller ones created using laser drilling.<\/p>\n
However, there are no specific requirements for the composition of HDI PCB layouts; therefore, most designers believe that once a design includes microvias, it can be consideredHDI Board<\/a>. However, before you begin designing, you need to establish some design rules. Before you start formulating these design rules, you should first understand your manufacturer\u2019s capabilities, as this will have a significant impact on the design.<\/p>\n The following are some key design rules to consider before laying out an HDI PCB:<\/p>\n Via size and trace width are critical factors in determining when to transition to an HDI system. As trace width decreases, via size also decreases, which may ultimately require the fabrication of micro-vias. Therefore, these parameters must be determined before design begins.<\/p>\n The design and aspect ratio of through-holes require careful consideration, depending on the required layer thickness. You should define layer transitions early on so that you can place them quickly during routing.<\/p>\n Ensure there is sufficient space between traces and between traces and other objects (such as pads, components, planes, etc.) to comply with HDI DFM (Design for Manufacturability) rules and prevent excessive crosstalk.<\/p>\n Factors such as trace length matching, maximum trace length, and allowable impedance deviation are all important design rules, but these generally apply to non-HDI boards as well. However, in HDI board design, via size and trace width are the most critical factors.<\/p>\n HDI layer stacks can range from a few layers to several dozen to meet the required routing density. Ball grid array (BGA) circuit boards with a high number of pins and fine pitch can have hundreds of connections per quadrant; therefore, through-holes are critical when creating the layer stack for an HDI PCB layout.<\/p>\n In some PCB design software, you may not be able to directly define layer transitions as microvias, but you can still create layer transitions and set via size constraints. You can then define spacing constraints separately for design rules governing via routing, setting specific spacing based on pad size and via diameter.<\/p>\n Before establishing design rules, we recommend that you consult with the manufacturer to understand its manufacturing capabilities, to ensure that the rules you set are aligned with those capabilities.<\/p>\n You can use a variety of tools to determine the required trace width, depending on whether impedance control is necessary.<\/p>\n If impedance control is not required, you can set any trace width. Otherwise, you need to determine the impedance curve for the PCB stackup and enter that specific width into the design rules.<\/p>\n Care must be taken when setting the trace width, as it affects the size of the via pads. If the trace width required for impedance control is too wide, you can compensate by reducing the laminate thickness or increasing the pad size, as long as the design still complies with IPC standards.<\/p>\n Once you have set the desired width, simply define it as a design rule. The integrated field solver can be used to define impedance curves and ensure that trace widths comply with specifications.<\/p>\n During the layout and routing of HDI PCBs, establishing key design rules is essential to ensure the performance and reliability of the circuit board. Via size and trace width are critical factors in the design process, and adhering to design rules\u2014particularly those related to crosstalk\u2014will help ensure the smooth manufacturing and reliable operation of HDI PCBs.<\/p>\n If you use the appropriate design rules in your PCB design software, you can more easily design high-density interconnect (HDI) boards and ensure they meet your project requirements.<\/p>\n Learn more about HDI PCB layout to enhance your electronic design capabilities.<\/p>\n HDI PCBs (High-Density Interconnect PCBs) differ from standard PCBs in terms of component and trace density. HDI PCBs typically feature smaller through-holes and narrower traces to meet the requirements of high-density layouts.<\/p>\n Through-hole dimensions and trace widths should be determined based on design rules and the manufacturer\u2019s capabilities. It is recommended to consult the manufacturer before designing to obtain accurate parameters.<\/p>\n The stack-up of an HDI PCB refers to the combination of layers, which can range from a few to several dozen. It is designed to meet the demands of high-density routing, particularly on circuit boards featuring BGAs with a high pin count and fine pitch.<\/p>\n Ensuring the reliability of HDI PCBs requires establishing appropriate design rules, particularly regarding via size, trace width, and impedance control. In addition, working closely with the manufacturer to understand its capabilities is key to ensuring reliability.<\/p>\n Crosstalk refers to the interference that occurs between signals on adjacent conductors or traces. In high-density HDI PCBs, controlling crosstalk is critical to ensuring signal integrity.<\/p>\n Related Reading<\/strong>\uff1a9 Factors to Consider When Evaluating the Feasibility and Cost of HDI Manufacturing<\/a> \u00b7 Applications of Laser Drilling in HDI Printed Circuit Boards<\/a><\/p>","protected":false},"excerpt":{"rendered":" \u968f\u7740\u7535\u5b50\u8bbe\u5907\u4e0d\u65ad\u6f14\u8fdb\uff0c\u66f4\u9ad8\u7ea7\u7684PCB\uff08Printed Circuit Board\uff0c\u5370\u5237\u7535\u8def\u677f\uff09\u8bbe\u8ba1\u9700\u8981\u5728\u66f4\u5c0f\u7684 […]<\/p>\n","protected":false},"author":1,"featured_media":6052,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"How to Set Up Layout and Routing for HDI PCBs? Via Sizes, Layer Transitions, and Routing Constraints","description":"How do you set up the layout and routing for HDI PCBs? This guide explains design rules such as via dimensions and trace widths, layer transitions, clearing, and other routing restrictions. It also highlights common pitfalls to help you avoid easily overlooked details."},"_slim_seo_primary_term_category":0,"_slim_seo_primary_term_post_tag":0,"footnotes":""},"categories":[405,26],"tags":[],"class_list":["post-2985","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-pcb-design","category-blog"],"_links":{"self":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2985","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/comments?post=2985"}],"version-history":[{"count":4,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2985\/revisions"}],"predecessor-version":[{"id":19527,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2985\/revisions\/19527"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media\/6052"}],"wp:attachment":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media?parent=2985"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/categories?post=2985"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/tags?post=2985"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}1. Through-hole Dimensions and Trace Width<\/h3>\n
2. Layer Transitions<\/h3>\n
3. Clear<\/h3>\n
4. Other Routing Restrictions<\/h3>\n
Laminates and Through-Holes<\/h2>\n
Wire Width<\/h2>\n
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Conclusion<\/h2>\n
Frequently Asked Questions<\/h2>\n
1. What is the difference between HDI PCBs and standard PCBs?<\/h3>\n
2. How do you determine the size of through-holes and the width of traces?<\/h3>\n
3. What is an HDI PCB stackup?<\/h3>\n
4. How can the reliability of HDI PCBs be ensured?<\/h3>\n
5. What is crosstalk?<\/h3>\n