Hierarchically Defining Bump and Pin Regions Overcomes 3D IC Complexity

Categories: 3D IC, Chiplet, EDA, Siemens EDA

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Key Takeaways

• Chiplets offer modular, flexible, and cost-efficient system integration but also significantly increase package assembly complexity.

• Hierarchical device planning is essential for abstracting and managing the rising intricacies of modern IC packaging.

• Early SI/PI and thermal analysis is critical to avoid costly redesigns and guide key architectural decisions throughout the design cycle.

By Todd Burkholder and Per Viklund, Siemens EDA

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Introduction: The Rise of Chiplets and the Complexity Challenge

Advanced IC packaging is undergoing a transformation. As the semiconductor industry shifts toward heterogeneous integration, designers are merging diverse chiplets, dies, interposers, and bridges into unified 3D-stacked systems. This approach delivers unprecedented flexibility and performance — but dramatically increases design complexity.

Chiplets are at the forefront of this trend. Their modular, standards-based architecture accelerates innovation while reducing manufacturing costs. However, this shift comes with a cost: package pin counts have grown from ~100,000 to more than 50 million, and projections suggest even more explosive growth ahead.

No single designer can manually manage such massive connectivity. The industry needs a way to abstract complexity and create reusable, optimized functional building blocks. That’s where hierarchical device planning becomes indispensable.

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Why Traditional Methods Fall Short

Not long ago, managing 100,000 connections with spreadsheets and flat design methods was painful but feasible. Today, that approach is impossible.

Modern designs involve:

• Millions to tens of millions of pins

• Constant design iteration

• Concurrent chip-package co-design

• Multiple chiplets, interposers, and bridges evolving in parallel

Manual approaches break down due to:

• Missing or outdated data

• Lack of synchronization

• Complex interface dependencies

• High risk of assembly errors

And the consequences can be catastrophic — failed packages costing millions, schedule slips, or even the collapse of a company. The semiconductor industry has already experienced such failures.

Today’s reality demands fully integrated, intelligent design methodologies that keep pace with package complexity.

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A New Paradigm: Hierarchical Device Planning

Hierarchical device planning restructures IC packaging into manageable layers. Instead of wrestling with millions of pins individually, designers define hierarchical, parameterized bump/pin regions that can be planned, optimized, and validated at the right level of abstraction.

The Core Benefits

• Abstracted complexity: Designers work with functional regions, not millions of pins.

• Reusable optimized blocks: Sub-devices and floorplans can be deployed across derivative designs.

• Automatic pin synthesis: When parameters change, the system updates all pins automatically.

• Faster iteration: Design changes that once took weeks can now be resolved in days.

• Improved accuracy: Fewer manual steps means fewer opportunities for errors.

This approach redefines how package planners manage connectivity across multi-die 3D ICs.

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The Need for Early Multi-Domain Analysis

As 3D IC architectures grow more complex, early SI, PI, thermal, and stress analysis become essential. Issues detected late in the flow can trigger full package redesigns — an extremely costly and time-consuming scenario that modern schedules cannot tolerate.

Hierarchical planning supports early analysis by:

• Providing structured models

• Allowing iterative refinement

• Guiding design choices at the system level

This proactive approach prevents downstream failures and ensures robust system performance.

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Enabling 3D IC Innovation with Siemens’ Innovator 3D IC

Siemens’ Innovator 3D IC portfolio is engineered to support the industry’s shift toward advanced heterogeneous systems. Its capabilities include:

• Hierarchical device planning for complex 2.5D & 3D ICs

• Full connectivity tracking across multi-die assemblies

• Early SI/PI/thermal evaluation

• Advanced floorplanning and optimization

• AI-infused user experience

• Robust work-in-progress data management

A critical feature is automated version control and error detection. Forgetting to import an updated Verilog file or mismatched interface definitions can corrupt an entire package build. Innovator 3D IC prevents these pitfalls with integrated, automated checks.

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Moving Toward Industry-Wide Standards and Methodologies

The exploding complexity of 3D ICs requires an ecosystem of:

• New design methodologies

• Better cross-domain collaboration

• Standardized chiplet communication protocols

Standards like UCI Express, Bunch of Wires (BOW), and AIS are emerging to streamline chiplet interoperability.

Most importantly:
Designers must realize their challenges are not unique — the industry shares them, and solutions already exist.

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Conclusion: Managing Complexity Through Abstraction

As IC packaging surges toward tens of millions of pins and increasingly intricate multi-die assemblies, hierarchical device planning has emerged as a foundational methodology. By defining bump and pin regions hierarchically, designers can abstract complexity, streamline iteration, prevent costly errors, and accelerate the development of next-generation 3D IC systems.

The path forward is clear:
Adopt advanced tools, embrace hierarchical planning, and design at the right abstraction level.
It is the only way to meet the demands of modern 3D IC and chiplet-based systems — and to deliver the future of electronic design.