Materials / Compare
PCB Laminate FR-4 vs. Silicon
Compare PCB Laminate FR-4 vs. Silicon strength, stiffness, weight and thermal properties.
| Try it on a partA panel to run stress or thermal on, free in your browser | Open in LessCAD | Open in LessCAD |
|---|---|---|
| Mechanical | ||
| Yield strength | not given (tensile used) | not given (tensile used) |
| Ultimate tensile strength | 246–385MPasourcetypical, in-plane: cross direction .. length direction (ASTM D3039) | 130MPasourcemodulus of rupture (bending fracture stress); brittle, no yield point |
| Flexural strength | 531–621MPasourcetypical: cross direction .. length direction (IPC-TM-650 2.4.4B) | 130MPasourcemodulus of rupture |
| Elongation at break | not sourced | not sourced |
| Young's modulus (stiffness) | 21.9–25.8GPasourcetypical, in-plane: cross direction .. length direction (ASTM D790-15e2) | 131GPasourcetypical (single quoted value of an anisotropic crystal) |
| Density | 1,920kg/m³sourcetypical, 50% resin content; another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR | 2,329kg/m³sourcetypical |
| Strength to weight | 164kN·m/kg2.94x higher | 55.8kN·m/kg |
| Stiffness to weight | 12.4MN·m/kg | 56.2MN·m/kg4.53x higher |
| Poisson's ratio | 0.171–0.177sourcetypical, in-plane: cross direction .. length direction | 0.221sourcetypical |
| Shear modulus | 10.2GPa | 53.6GPa5.28x stiffer in shear |
| Bulk modulus | 12.2GPa | 78.3GPa |
| Speed of sound | 3,525m/s | 7,500m/s |
| Thermal | ||
| Thermal conductivity | 0.4W/m·Ksourcetypical (ASTM E1952); direction not stated by the sheet | 163W/m·Ksourcetypical at 313 K (40 °C) |
| Thermal expansion | 13–14µm/m·Ksourcetypical, in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C) | 2.62µm/m·Ksourcetypical at 300 K |
| 100 mm part over a 50 °C swing | 67.5µm growth | 13.1µm growth5.15x less |
| Specific heat | 1,200–1,400J/kg·Ksourcetypical (ASTM E1461); another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR | 732J/kg·Ksourcetypical |
| Heats up and cools (diffusivity) | 0.16mm²/s | 95.6mm²/s597x faster |
| Thermal shock resistance | 324W/m | 48,095W/m149x more resistant |
| Melting point | not sourced | 1,412°Csourcetypical |
| Glass transition | 180°Csourcetypical, DSC (IPC-TM-650 2.4.25C) | not sourced |
| Max service temperature | 130°CsourceUL Relative Thermal Index (UL 796) | 300°Csourceproducer's maximum application temperature (optical components) |
| Values for | Isola 370HR FR-4 laminate (Polyclad PCL-FR-370HR, 180 C Tg multifunctional epoxy, E-glass fabric), copper removed; Isola data sheet Revision C, last updated April 15, 2021. Woven-glass laminate: the sheet gives in-plane values per weave direction (length / cross) and the Z-axis CTE separately; the solver is isotropic per material. | Synthetic single-crystal silicon (cubic, diamond structure), Korth Kristalle (crystal grower) material data; Korth usually supplies Floating Zone (FZ) material, Czochralski (Cz) also offered. Silicon is elastically anisotropic; the producer quotes one modulus and the solver is isotropic. |
Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.
Questions
Is PCB Laminate FR-4 stronger than Silicon?
PCB Laminate FR-4 is stronger: its tensile strength is 315 MPa against 130 MPa for Silicon (2.43x).
Which is lighter, PCB Laminate FR-4 or Silicon?
PCB Laminate FR-4 is lighter: 1,920 kg/m³ against 2,329 kg/m³ for Silicon.
Which is stiffer, PCB Laminate FR-4 or Silicon?
Silicon is stiffer: Young's modulus 131 GPa against 23.9 GPa for PCB Laminate FR-4, so the same part in Silicon deflects less under the same load.
Which is lighter for the same job, PCB Laminate FR-4 or Silicon?
For the same stiffness or strength: PCB Laminate FR-4 is lighter for a strong rod or tie, strong beam, strong panel or plate; Silicon is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate.
| Part that must be | PCB Laminate FR-4 | Silicon |
|---|---|---|
| Stiff rod or tie (tension) | 4.53x heavier | lighter |
| Stiff beam (bending) | 1.93x heavier | lighter |
| Stiff panel or plate | 45% heavier | lighter |
| Strong rod or tie | lighter | 2.94x heavier |
| Strong beam | lighter | 2.19x heavier |
| Strong panel or plate | lighter | 1.89x heavier |
For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).
Which conducts heat better, PCB Laminate FR-4 or Silicon?
Silicon conducts heat better: 163 W/m·K against 0.4 W/m·K for PCB Laminate FR-4.
Which expands less with temperature?
Silicon expands less: 2.62 µm/m·K against 13.5 µm/m·K for PCB Laminate FR-4.