Advanced Physical Etching and Deposition Simulator

Elite is an advanced 2D topography simulator for modeling physical etching, deposition, reflow and CMP planarization processes for modern semiconductor technologies. Within the Athena framework, Elite provides seamless bi-directional integration with SSuprem 4 and Optolith process simulators and contains an additional MC Etch & Depo Simulator, which provides several Monte Carlo based atomistic etching and deposition models.

 

Advanced Semiconductor Topology Simulation Solutions

  • Elite predicts the topology evolution during complex processes such as multi-level metallization, deep trench etching, CVD, APCVD, LPCVD, plasma etching, and ion milling
  • Elite provides a time efficient and cost effective alternative for solving problems encountered in processes using aggressive topographical design rules
  • The comprehensive capabilities of Elite enable accurate simulation of critical process issues such as material planarization, step coverage, formation of voids and microstructure cracks, and modeling of interconnect stringers and fillets
  • Seamless interface with layout editor MaskViews allows investigation of CD variation and misaligment effects on individual topological processes and final structures
  • Chemical Mechanical Polishing (CMP) and material reflow models provide analysis capabilities for critical planarization processes

 

Models and Features

  • Seamless integration with Optolith lithography simulator and SSuprem 4 process simulator
  • Fast and robust algorithm for material surface evolution
  • Supports etching and deposition machine library definition
  • Includes several default machine definitions

 

Deposition Models

  • 8 physical models: Conformal, CVD, uni-directional, dual-directional, hemispherical, planetary, conical, and custom defined Model
  • Microstructure crack formation
  • Density variation during metallization
  • Physical sputtering

 

Etch Models

  • RIE model combines isotropic and directional etching
  • Wet etching based on isotropic profile evolution
  • Ion milling model
  • Beam divergence for dry etch modeling
  • Doping and stress dependent etch rates
  • Microloading effects

 

Reflow Effects

  • Chemical Mechanical Polishing (CMP)
  • Polishing pad degradation model
  • Pattern density effects
  • Shadowing effects
  • Simultaneous chemical and mechanical erosion

Multi-Level Interconnect

Accurate descriptions of multi-level interconnect structures can be simulated with Elite. The figure shown above illustrates the capability to evaluate the tightly spaced interconnect lines and dielectric film uniformity of complicated interconnect structures. The interface with SSuprem4 allows doping and oxidation profiles to be included in the structure.

 

Microloading Effect

The etch models in Elite take into account both geometrical and advanced physical effects. The figure above shows the effect of microloading for Reactive Ion Etching. The effective etch rate on the bottom of the trench is smaller for narrower mask windows because the local ion flux is reduced due to shadowing effect.

 

Bonded SOI Wafer and Deep Trench Isolation Process

This example shows the combination of an Elite and SSuprem 4 simulation of the deep trench isolation process on the Bonded SOI wafer. A bipolar power device has been formed in this structure. The reflow effect on the surface contact for the power automotive device is also considered.

 

Inter-metal Dielectric Void Formation

Elite can optimize a process to avoid formation of superfluous voids during deposition. The example above shows the use of two conductors (poly and aluminum) that are close together. The narrow gap between them can form a void after TEOS deposition as demonstrated in this example. The type of inter-metal dielectric material, thickness of this dielectric, method of insulation as well as design rules may affect the integrity of multi-level metallization.

 

Elite includes a module for evaluating the effects of CMP processes. The figure above illustrates the resulting surface evolution during a CMP of a dielectric test-structure. Such simulations could be used to investigate effects related to pattern density

 

Metal Step Coverage After Reflow

This figure illustrates the ability of Elite to model metal step coverage in a contact via after reflow. Topographical descriptions such as this are useful for analyzing and avoiding failure mechanisms during multi-level deposits and patterning steps.

 

Deep Trench Etching and Epitaxial Growth

The combination of SSuprem 4 and Elite can be used to optimize a Super Junction formation process, which is very popular in power device electronics. One of the methods of manufacturing of pillar-like p-n junctions consists of etching several deep trenches in n-type substrate with subsequent deposition/anneal or epitaxial growth of p-type silicon. This figure shows Elite simulation of the Deep Trench Etching using RIE and CVD deposition of p-type material. Ssuprem4 is used to simulate the non-planar epitaxial growth with impurity redistribution and p-n junction formation.

 

Stress Dependent Etch Rate Model

Elite allows an estimation of the effect of heavy doping or stress on the etching rates. This figure demonstrates effect of the stress formed during mask pattering on the subsequent RIE etching.

 

Rev. 090413_08