In this work, we investigate the abundance and distribution of metals in the intergalactic medium (IGM) at $⟨z⟩\simeq 2.8$ through the analysis of an ultra-high signal-to-noise ratio UVES spectrum of the quasar HE0940-1050. In the CIV forest, our deep spectrum is sensitive at $3\sigma$ to lines with column density down to $\log NCIV\simeq 11.4$ and in 60 per cent of the considered redshift range down to $\simeq 11.1$. In our sample, all HI lines with $\log NHI\ge 14.8$ show an associated CIV absorption. In the range , 43 per cent of HI lines has an associated CIV absorption. At , the detection rates drop to per cent, possibly due to our sensitivity limits and not to an actual variation of the gas abundance properties. In the range $\log NHI\ge 14$, we observe a fraction of HI lines with detected CIV a factor of 2 larger than the fraction of HI lines lying in the circum-galactic medium (CGM) of relatively bright Lyman-break galaxies hosted by dark matter haloes with $⟨M⟩\sim 1012$ M$\mathrm{<mrow\; data-mjx-texclass="ORD">\odot </mrow>}$. The comparison of our results with the output of a grid of photoionization models and of two cosmological simulations implies that the volume filling factor of the IGM gas enriched to a metallicity $\log Z/Z\odot \ge -3$ should be of the order of $\sim 10-13$ percent. In conclusion, our results favour a scenario in which metals are found also outside the CGM of bright star-forming galaxies, possibly due to pollution by lower mass objects and/or to an early enrichment by the first sources.