  We present an effective field theory suitable to describe a non-relativistic
particle-antiparticle pair of heavy scalars based on the gauge group SU(3). Its
formulation is analogous to that of "velocity NRQCD" (vNRQCD), a
non-relativistic effective theory for heavy quark pairs. The matching
conditions with scalar QCD and the renormalization group evolution of the
effective theory are discussed. The non-relativistic framework proposed here
suffices to compute scalar-antiscalar bound state energies at
next-to-next-to-leading-logarithmic (NNLL) order and
next-to-leading-logarithmic (NLL) threshold production of squarks in $e^+e^-$
and $\gamma\gamma$ collisions, in particular of the lighter scalar top quark at
a future Linear Collider.
