This work explores from a statistical point of view the rest-frame Far-ultraviolet (FUV) to Far-infrared (FIR) emission of a population of Lyman break galaxies (LBGs) at $zsim3$ that cannot be individually detected from current FIR observations. We perform a stacking analysis over a sample of $sim$17000 LBGs at redshift $2.5<z<3.5$ in the COSMOS field. The sample is binned as a function of UV luminosity ($L_{mathrm{FUV}}$), UV continuum slope ($beta_{mathrm{UV}}$), and stellar mass (M$_{*}$), and then, stacked at optical ($BVriz$ bands), near-infrared ($YJHKs$ bands), IRAC (3.6, 4.5, 5.6 and 8.0 $mu$m), MIPS (24$mu$m), PACS (100 and 160~$mu$m), SPIRE (250, 350, and 500~$mu$m), and AzTEC (1.1mm) observations. We obtain thirty rest-frame FUV-to-FIR spectral energy distribution (SEDs) of LBGs at $zsim3$, and analyse them with CIGALE SED-fitting analysis code. We are able to derive fully consistent physical parameters (M$_{*}$, $beta_{mathrm{UV}}$, $L_{mathrm{FUV}}$, $L_{mathrm{IR}}$, A$_{FUV}$, SFR, and slope of the dust attenuation law), and build a semi-empirical library of thirty rest-frame FUV-to-FIR stacked LBG SEDs as a function of $L_{mathrm{FUV}}$, $beta_{mathrm{UV}}$, and M$_{*}$. We used the so-called IR-excess ($IRX equiv L_{mathrm{IR}} / L_{mathrm{FUV}}$) to investigate the dust attenuation as a function of $beta_{mathrm{UV}}$ and M$_{*}$. Additionally, the SED-fitting analysis results provide a diversity of dust attenuation curve along the LBG sample, and their slope are well correlated with M$_{*}$. Stepper dust attenuations curves than Calzettis are favoured in low stellar mass LBGs ($log(M_{*} [M_{odot}]) < 10.25$), while grayer ones are favoured in high stellar mass LBGs ($log(M_{*} [M_{odot}]) > 10.25$).
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