We study a singular perturbation problem arising in the scalar twophase field model. Given a sequence of functions with a uniform bound on the surface energy, assume the Sobolev norms W 1, p of the associated chemical potential fields are bounded uniformly, where p > n 2 and n is the dimension of the domain. We show that the limit interface as ε tends to zero is an integral varifold with a sharp integrability condition on the mean curvature.