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Hybrid PCBs for Next Generation Applications
Friday, November 18, 2022
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Section: PCB & Laminates
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Projects Leaders


Sarah Czaplewski, IBM


Steve Ethridge, Dell

Call-for-Participation Webinar

Call-for-participation webinar presentation (December 7, 2022)
 

Project Statement & SOW

Statement of Work
Project Statement


Background

An increasing range of high-speed applications require low loss dielectric laminate materials within a printed circuit board (PCB) stack-up to achieve the required electrical performance. However, low loss laminate materials are more expensive than standard loss materials. One solution to minimize cost is to selectively use lower loss material on only the layers that require higher performance, and use cheaper material on layers that do not require high performance. This “hybrid” combination of laminate materials can provide the required electrical performance at minimum cost.
 
However, the combination of dissimilar dielectric materials has associated challenges for PCB fabrication that can negatively impact reliability if manufacturing processes are not optimized and/or the materials are in some way incompatible. Selection of materials must be carefully considered, especially as new materials are continually being developed and as PCB performance requirements include increased utilization of microvia structures and consideration of hybrid stack-ups that may include asymmetry or more than two laminate materials.
 
It is against this background that an informed and comprehensive study is required to document and assimilate current recommendations and best practices for designing and manufacturing reliable hybrid PCBs. In the initial phase of developing the project scope, an industry survey was conducted with participation from laminate material suppliers, PCB fabricators, and OEMs. Survey results showed that determining material compatibility and minimizing warpage are among the biggest challenges in hybrid PCB manufacturing. Based on these and other areas identified by the survey, the following tasks were identified as high-priority:
  • Evaluate the impact of material placement within the stack-up on reliability and warpage
  • Study the influence of coefficient of thermal expansion (CTE) mismatch on hybrid reliability
  • Determine the drivers of warpage in asymmetric hybrid PCBs
  • Evaluate the impact of hybrid use on microvia reliability
 

Project Focus

This project aims to evaluate how placement of dielectric materials with dissimilar properties within a hybrid stack-up impacts PCB thermomechanical performance using a commercially available simulation software. Through multiple tasks, the project team will study the impact of the following parameters on via hole reliability (potentially including microvias) and PCB warpage: 
  • The impact of material placement within a symmetrical hybrid stack-up with materials having different properties such as CTE and/or gel point
  • The impact of having various ratios of dissimilar dielectric materials in a symmetrical hybrid stack-up (i.e., 25% material A & 75% material B; 50% material A & 50% material B, etc.)
  • The impact of resin asymmetry in the stack-up
 At the end of the project, findings will be summarized along with any insights and recommendations for hybrid PCB material selection and stack-up design.
 

Project Benefits & Value to Industry

 The benefits of this project will include:
  • Increased knowledge of how material placement in a hybrid stack-up influences PCB thermomechanical performance to enable creation of more robust designs earlier in product development
  • Better understanding of how differences in dielectric material properties impact hybrid PCB thermomechanical performance
  • Exposure to simulation tools for evaluating PCB hybrid stack-ups that may help to reduce engineering design iterations and manufacturing trial builds
The results of this project will increase understanding of how hybrid stack-up designs influence PCB thermomechanical performance. OEMs and PCB manufacturers may use this information to improve stack-up designs to be more robust and reliable as well as reduce the number of design and test iterations, thereby saving cost and development time. Laminate manufacturers may use this information to help tailor resin systems for use in hybrid constructions to better support customer needs. 
 

Presentations

Hybrid PCBs for Next Generation Applications – Results of Industry Survey (webinar presentation & recording, April 2022)
 

Steps for Joining the Project

Please note: iNEMI membership is required to participate in this project. Steps for joining the project follow.

For iNEMI members:
  • Complete and sign the Project Statement (above)
  • Email the completed statement to infohelp@inemi.org.
For non-members:
 

Contact

infohelp@inemi.org