Editing Printed circuit board (section)

=== Common substrates ===
Often encountered materials:
* [[FR-2]], [[phenolic paper]] or phenolic cotton paper, paper impregnated with a [[phenol formaldehyde resin]]. Common in consumer electronics with single-sided boards. Electrical properties inferior to FR-4. Poor arc resistance. Generally rated to 105&nbsp;°C. 
* [[FR-4]], a woven [[fiberglass]] cloth impregnated with an [[epoxy resin]]. Low water absorption (up to about 0.15%), good insulation properties, good arc resistance.  Very common. Several grades with somewhat different properties are available. Typically rated to 130&nbsp;°C. 
* [[Aluminum]], or ''metal core board'' or [[insulated metal substrate]] (IMS), clad with thermally conductive thin dielectric - used for parts requiring significant cooling - power switches, LEDs. Consists of usually single, sometimes double layer thin circuit board based on e.g. FR-4, laminated on aluminum sheet metal, commonly 0.8, 1, 1.5, 2 or 3&nbsp;mm thick. The thicker laminates sometimes also come with thicker copper metalization.<ref>{{cite web |last=Fjelstad |first=Joseph |url=https://www.circuitinsight.com/pdf/manufacture_aluminum_substrate_pcbs_ipc.pdf |title=Method for the Manufacture of an Aluminum Substrate PCB and its Advantages |website=CircuitInsight.com |access-date=January 17, 2024 }}</ref><ref>{{cite journal |last=Yung |first=Winco K. C. |date=2007 |url=https://www.bestpcbs.com/public/pdf/Metal-Core-PCB-design-guide.pdf |title=Using Metal Core Printed Circuit Board (MCPCB) as a Solution for Thermal Management |journal=Journal of the HKPCA |issue=24 |pages=12–16}}</ref>
* [[Flexible electronics|Flexible substrates]] - can be a standalone copper-clad foil or can be laminated to a thin stiffener, e.g. 50–130&nbsp;μm
** [[Kapton]] or [[UPILEX]],<ref>{{cite web |url=http://www.upilex.jp/en/application.html|title= Applications {{!}} UBE Heat Resistant Polyimide Materials |publisher=UBE |website=Upilex.jp }}</ref> a [[polyimide]] foil. Used for [[Flexible electronics|flexible printed circuits]], in this form common in small form-factor consumer electronics or for flexible interconnects. Resistant to high temperatures.
** [[Pyralux]], a polyimide-fluoropolymer composite foil.<ref>{{cite web |url=http://www.dupont.com/products-and-services/electronic-electrical-materials/flexible-rigidflex-circuit-materials/brands/pyralux-flexible-circuit.html |title=Pyralux Flexible Circuit Materials |publisher=DuPont }}</ref> Copper layer can delaminate during soldering.

Less-often encountered materials:

* FR-1, like FR-2, typically specified to 105&nbsp;°C, some grades rated to 130&nbsp;°C. Room-temperature punchable. Similar to cardboard. Poor moisture resistance. Low arc resistance.
* FR-3, cotton paper impregnated with epoxy. Typically rated to 105&nbsp;°C.
* FR-5, woven fiberglass and epoxy, high strength at higher temperatures, typically specified to 170&nbsp;°C.
* FR-6, matte glass and polyester
* [[G10 (material)|G-10]], woven glass and epoxy - high insulation resistance, low moisture absorption, very high bond strength. Typically rated to 130&nbsp;°C.
* G-11, woven glass and epoxy - high resistance to solvents, high flexural strength retention at high temperatures.<ref>{{cite book|url=https://books.google.com/books?id=nnCNsjpicJIC&q=printed+circuit+board+materials+%22fr-1%22&pg=PA475|title=Op Amps for Everyone|first=Bruce|last=Carter|date=March 19, 2009|publisher=Newnes|via=Google Books|isbn=9780080949482}}</ref> Typically rated to 170&nbsp;°C.
* CEM-1, cotton paper and epoxy
* CEM-2, cotton paper and epoxy
* CEM-3, non-woven glass and epoxy
* CEM-4, woven glass and epoxy
* CEM-5, woven glass and polyester
* [[PTFE]], ("Teflon") - expensive, low dielectric loss, for high frequency applications, very low moisture absorption (0.01%), mechanically soft. Difficult to laminate, rarely used in multilayer applications.
* PTFE, ceramic filled - expensive, low dielectric loss, for high frequency applications. Varying ceramics/PTFE ratio allows adjusting dielectric constant and thermal expansion.
* RF-35, fiberglass-reinforced ceramics-filled PTFE. Relatively less expensive, good mechanical properties, good high-frequency properties.<ref>{{cite web |date=September 1, 1998 |url=http://www.microwavejournal.com/articles/2426-a-high-performance-economical-rf-microwave-substrate |title=A High Performance, Economical RF/Microwave Substrate |publisher=MicrowaveJournal.com |access-date=November 4, 2024 }}</ref><ref>{{cite web |url=http://www.multi-circuit-boards.eu/fileadmin/user_upload/downloads/e_taconic_rf35-hf_www.multi-circuit-boards.eu.pdf |title=RF-35 datasheet |publisher=Taconic |via=Multi-CB }}</ref>
* [[Alumina]], a ceramic. Hard, brittle, very expensive, very high performance, good thermal conductivity.
* [[Polyimide]], a high-temperature polymer. Expensive, high-performance. Higher water absorption (0.4%). Can be used from cryogenic temperatures to over 260&nbsp;°C.