Layer minimization of escape routing in area array packaging

ABSTRACT

We devise a central triangular sequence to minimize the escape routing layers in area array packaging. We use a network flow model to analyze the bottleneck of the routable pins. The triangular patterns are generated in a reverse order from the last to the first layer. We demonstrate that the triangular pin sequence maximizes the sum of escape pins in the accumulated layers and thus minimize the number of escape routing layers. A test case is presented to illustrate the approach.

REFERENCES

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• 2: E. Winkler, "Escape Routing from Chip Scale Packages," IEEE/CPMT Int. Electronics Manufacturing Technology Symp., pp. 393--401, 1996.
• 3: Man-Fai Yu , Wayne Wei-Ming Dai, Single-layer fanout routing and routability analysis for Ball Grid Arrays, Proceedings of the 1995 IEEE/ACM international conference on Computer-aided design, p.581-586, November 05-09, 1995, San Jose, California, United States
• 4: N. M. Gasparini, "A Method of Designing a Group of Bumps for C4 Packages to Maximize the Number of Bumps and Minimize the Number of Package Layers," Electronic Components and Technology Conference, pp. 695--696, 1994.
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• 6: Wun-Tat Chan , Francis Y. L. Chin , Hing-Fung Ting, Escaping a grid by edge-disjoint paths, Proceedings of the eleventh annual ACM-SIAM symposium on Discrete algorithms, p.726-734, January 09-11, 2000, San Francisco, California, United States
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INDEX TERMS

Primary Classification:
  B. Hardware
  B.7 INTEGRATED CIRCUITS
      B.7.2 Design Aids
          Subjects: Placement and routing

Additional Classification:
  B. Hardware
  B.7 INTEGRATED CIRCUITS
      B.7.2 Design Aids
          Subjects: Layout
  B.8 Performance and Reliability
      B.8.2 Performance Analysis and Design Aids

  F. Theory of Computation
  F.2 ANALYSIS OF ALGORITHMS AND PROBLEM COMPLEXITY
      F.2.2 Nonnumerical Algorithms and Problems
          Subjects: Routing and layout

General Terms:
Algorithms, Design, Performance

Keywords:
bottleneck analysis, central triangular pattern, escape routing