A model and simulator that describe the dependence of deposition rate and bump formation on pattern density during electrochemical deposition ͑ECD͒ are presented. A curvature-enhanced ECD model from the recent literature ͓A.C. West et al., 4, C50, ͑2001͔͒ is used in a feature scale process simulator to explain bump formation and to qualitatively explain some observed pattern density effects. Experimentally, it is known that ECD topographies can be different when features are clustered together compared to isolated features. Although it is difficult to experimentally quantify the extent of bumping over patterned regions of wafers, the curvature-based models for bumping are at least qualitatively consistent with reported trends in deposit shape with feature density.In electrochemical deposition ͑ECD͒ processes used in integrated circuit ͑IC͒ fabrication, bath additives are often used to produce ''bottom-up'' filling of trenches and vias ͑features͒, in addition to other desirable process and film characteristics. 1-4 The filling enhancement due to these additives can be strong enough that they can actually cause a bump in the copper deposit over the trench, in a phenomenon called ''bumping'' ͑Fig. 1͒. 1,3 This effect can be accentuated by neighboring features and thus pattern density can greatly influence the shape and size of the deposited film. 5,6 These pattern density effects can have a large impact on post-ECD processing, particularly on surface planarization using chemical mechanical polishing ͑CMP͒. 6,7 West and co-workers, 1,2 and Josell and co-workers 3,4 presented models based upon curvature-enhanced deposition to explain bumping in some ECD baths under certain operating conditions. In these models, the interaction of additives with the surface causes bumping over features, such as shown in Fig. 2a. A concept common to these models is that an accelerator adsorbs on the surface and accumulates at a rate that depends strongly on the evolution of local curvature. Because the accelerator can affect the local copper deposition rate, either directly or indirectly through an intermediate species, the resulting variations in accelerator concentration on the surface are responsible for both bottom-up filling and the bumping phenomenon.We have demonstrated how to combine reactor-scale simulators with EVOLVE, 8 a feature scale simulator, to study the effects of groups of features on local deposition rates during LPCVD 9-11 and ECD. 12,13 The decrease in local deposition rates ͑''microloading''͒ due to the larger deposition areas in groups of features, relative to flat regions of the wafer, was studied by passing feature scale information to the reactor scale using homogenization. 9-14 We refer to the combination of reactor and features scales as integrated multiscale process simulation ͑IMPS͒. To accurately estimate the extent of microloading at each local region across the wafer, the correct deposition rates are needed. 9,10 In the studies cited above, we used deposition rate data from individual features. That is n...