HDI Best Practices
Best practices
<h1>HDI PCB Design Best Practices</h1>
<h2>Overview</h2>
<p>High-Density Interconnect (HDI) PCBs represent cutting-edge technology enabling smaller, faster, and more powerful electronic devices.</p>
<h2>Core Design Principles</h2>
<h3>1. Layer Stack-Up Planning</h3>
<ul>
<li>Use sequential lamination for complex designs</li>
<li>Implement 1+N+1 or 2+N+2 stack-up structures</li>
<li>Place signal layers adjacent to reference planes</li>
<li>Symmetrical stack-up to minimize warpage</li>
</ul>
<h3>2. Microvia Design (2025 Standards)</h3>
<ul>
<li>Diameter: ≤150 μm for standard HDI, ≤100 μm for ultra-HDI</li>
<li>Aspect ratio: ≤1:1 for reliability</li>
<li>Limit depth to 1-2 layers maximum</li>
<li>Pad size: 0.25-0.30mm</li>
</ul>
<h3>3. Via-in-Pad Technology</h3>
<ul>
<li>Direct laser drilling on component pads</li>
<li>Copper plating and planarization</li>
<li>Essential for BGAs with pitch ≤0.8mm</li>
</ul>
<h3>4. Trace Width and Spacing</h3>
<ul>
<li>Minimum: 2 mil (0.05mm)</li>
<li>Controlled impedance requires precise geometry</li>
<li>Differential pairs: match lengths within 5 mil</li>
</ul>
<h3>5. DFM Guidelines</h3>
<ul>
<li>Consult manufacturer for capabilities</li>
<li>Provide detailed stack-up specifications</li>
<li>Design for electrical testability</li>
</ul>
<h2>Applications</h2>
<ul>
<li>Consumer electronics (smartphones, wearables)</li>
<li>High-performance computing</li>
<li>Medical devices</li>
<li>Aerospace and defense</li>
</ul>
<hr>
<p><em>Based on industry best practices from <a href="https://www.allpcb.com/blog/pcb-knowledge/hdi-pcb-stackup-mastering-layer-configuration-for-optimal-performance.html">AllPCB</a>, <a href="https://www.tessolve.com/blogs/high-density-interconnect-hdi-pcb-design-best-practices-for-complex-products/">Tessolve</a>, and <a href="https://resources.pcb.cadence.com/blog/2024-hdi-pcb-design-guidelines-with-orcad-x">Cadence</a></em></p>
