Dummy Dies Enable Extended HBM Offsets in 2.5D Interposers

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Solution Overview

Problem

In 2.5D interposers, high-bandwidth memory (HBM) devices often require offsets due to IC size mismatches, leading to routing challenges that cannot be resolved by increasing ASIC size, which is impractical and costly, especially when design rules restrict chip area expansion.

Innovation Solution

Inserting dummy dies between ASIC and HBM on the interposer to increase the escape region, allowing 45-degree or orthogonal routing at extended offsets without enlarging the ASIC, using metallic dummy dies that maintain die-to-die gap rules and ensure signal integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If HBM is offset from corresponding PHY circuit pins due to IC size mismatches, then routing flexibility is improved, but routing difficulty increases

Engineering Contradiction:

Improverouting flexibilityVSAvoidrouting difficulty

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces dummy dies as intermediary elements between the HBM and the PHY circuit pins. These dummy dies serve as mediators that facilitate routing connections at extended offsets by providing additional escape regions and routing paths, thereby resolving the routing difficulty while maintaining the offset configuration for adaptability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If ASIC size is increased to resolve routing challenges, then routing capability is improved, but manufacturing cost increases

Engineering Contradiction:

Improverouting capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The patent segments the interposer structure by inserting dummy dies between the HBM and the PHY circuit. This segmentation creates additional escape regions and routing paths without requiring an increase in the ASIC die size, thereby maintaining manufacturing cost effectiveness while improving routing capability

Inventive Principle:

Principle #1Segmentation

3Area of stationary object

If chip area is expanded to accommodate routing, then routing space is improved, but design rule compliance becomes difficult

Engineering Contradiction:

Improverouting spaceVSAvoiddesign rule compliance

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent utilizes the vertical dimension of the interposer by stacking dummy dies between the HBM and the PHY circuit pins. This approach increases the available escape region and routing space in the vertical direction rather than expanding the chip area horizontally, thereby maintaining design rule compliance while providing sufficient routing space

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11538790B2Extended HBM offsets in 2.5D interposers

Publication Date: 2022.12.27 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

A semiconductor package includes an interposer, a number of a first integrated circuit (IC) dies, one or more second IC dies, and one or more dummy dies. The first IC dies, the second IC dies and the dummy dies are implemented on the interposer. The dummy dies are configured to enable routing of pins of the first IC dies to selected circuits of the second IC dies while conforming to predefined routing rules.