Systematic analysis for the kinematical corrections of cc-system in the diffractive lepto-productions of charmonia (1S, 2S) is presented within the light-cone perturbation theory. In the convolution of perturbative parts in the light-cone wave functions of a photon and a charmonium, the corrections are evaluated up to the order O(k_⊥~2/m_c~2) with k_⊥ being the relative momentum of cc-system and m_c the charm quark mass. We find the corrections to reduce effectively the large suppression by Fermi-motion effects predicted so far and strongly enhance the total cross sections of both J/ψ and ψ' productions. In addition, good agreement with recent data on Q~2 and s~(1/2) at HERA suggests that such systematic analysis is more reasonable in the color-dipole picture. We also discuss about the diffractive leptoproduction of botomonium, which could reduce an ambiguity from the Fermi-motion effect because of the heavier mass than the charm quark.
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