Model-based dummy feature placement for oxide chemical-mechanical polishing manufacturability

  • Authors:
  • Ruiqi Tian;D. F. Wong;R. Boone

  • Affiliations:
  • Dept. of Comput. Sci., Texas Univ., Austin, TX;-;-

  • Venue:
  • IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
  • Year:
  • 2006

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Abstract

Chemical-mechanical polishing (CMP) is an enabling technique used in deep-submicrometer VLSI manufacturing to achieve long range oxide planarization. Post-CMP oxide topography is highly related to local pattern density in the layout. To change local pattern density and, thus, ensure post-CMP planarization, dummy features are placed in the layout. Based on models that accurately describe the relation between local pattern density and post-CMP planarization by Stine et al. (1997), Ouma et al. (1998), and Yu et al. (1999), a two-step procedure of global density assignment followed by local insertion is proposed to solve the dummy feature placement problem in the fixed-dissection regime with both single-layer and multiple-layer considerations. Two experiments conducted with real design layouts gave excellent results by reducing simulated post-CMP topography variation from 767 Å to 152 Å in the single-layer formulation and by avoiding cumulative effect in the multiple-layer formulation. The simulation result from single-layer formulation compares very favorably both to the rule-based approach widely used in industry and to the algorithm by Kahng et al (1999). The multiple-layer formulation has no previously published work