Measurement of the phase $\phi_s$ at LHCb

One of the key goals of the LHCb experiment is the determination of the CP-violating phase $\phi_{s}$ in $\bar{b}\rightarrow \bar{c}c\bar{s}$ decays. Its value is predicted to be very small in the Standard Model. The measurements in the $B^{0}_{s}\rightarrow J/\psi \phi$, $B^{0}_{s}\rightarrow J/\psi\pi^{+}\pi^{-}$ and $B^{0}_{s}\rightarrow \psi(2S) \phi$ channels are reviewed. The first observation of the $B^{0}_{s}\rightarrow \eta_{c} \phi$ and $B^{0}_{s}\rightarrow \eta_{c} \pi^{+}\pi^{-}$ decay modes is presented. These channels can be used to measure $\phi_{s}$ with larger data statistics that will be collected during Run~II by the LHCb experiment.