High-power magnetron Cu seed deposition on 3-D dual inlaid features

Abstract

Cu seed deposition is an important step before electroplating when filling trenches and vias for interconnect manufacture. An integrated reactor to feature scale model has been applied to a high-power magnetron (HPM) source for Cu seed deposition. Images of the resulting Cu seed coverage on a canonical dual inlaid feature using the HPM source are presented. The dominant deposition specie is the Cu athermal, which has a broad angular distribution. The deposition results predict rounded profiles and via bottom and cusp formation at trench and via tops due to geometric shadowing of the Cu athermals. Index Terms-Copper deposition, dual inlaid, magnetron.A S CRITICAL dimensions shrink, aspect ratios increase, and transistor counts increase, manufacturing interconnects becomes an increasing challenge. Modeling can provide knowledge and a physical basis to help speed process development time for the interconnect manufacturing process. Part of the manufacturing process requires deposition of a copper "seed" (thin layer) onto trench and via structures prior to completely filling the structures with copper using an electroplating process. Modeling results for Cu seed deposition on a three-dimensional (3-D) dual inlaid feature used in interconnect manufacture will be discussed.An integrated reactor/feature scale model has been applied to a high-power magnetron (HPM) source for Cu seed deposition [1]. The reactor model used is HPEM [2], which is being developed at the University of Illinois. The feature scale model used is Papaya which is being developed at Motorola [3], Austin, TX. Papaya is a 3-D Monte Carlo (MC) model. The feature model tracks changes to a configuration of "pseudoparticles" in a "lattice" due to events on the surface. The inputs to the feature model (Papaya) calculated by the reactor model (HPEM) are the "atomic sources" which have an identity (Ar , Cu, Cu , and Cu.athermals), a flux rate (#/cm s), an angular distribution, and an energy distribution.The "atomic source" or "particles" are introduced at a "source plane" above the defined feature and their paths are tracked to the feature surface. Once a particle hits the feature surface, various processes occur depending on the particle's identity, energy, angle of incidence, and the material it hits. For instance, an Ar ion hitting the surface is not allowed to adsorb but may sputter material from the feature surface. The sputter rate depends on the material hit, the angle of incidence, and the energy of the Ar ion. The physical processes included in the fea-).Publisher Item Identifier S 0093-3813(02)03073-4. ture model are specie transport, adsorption, surface diffusion, reflection (diffusive, specular), energy loss, etch, sputter, and growth. The lattice is assumed to be face centered cubic (FCC) and is three-dimensional. The thermal accommodation coefficients, sticking coefficients, and sputter yields are functions of angle, energy, specie, and material [4].For the operating regime of the HPM considered here, the "atomic source" to the feature surface i...

A model for etching of three-dimensional high aspect ratio silicon structures in pulsed inductively coupled plasmas

“…With the increasing complexity of cyclic processing and the large number of process variables, three-dimensional (3D) feature scale modeling becomes attractive as it can provide keen insights into the fundamental etching and deposition mechanisms [14,15]. For example, during the multi-step etching process, usually consisting of passivation and etching steps, the model can investigate the effect of individual steps on the final results.…”