Compressible Structure for Multi-Chip Module Alignment

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Solution Overview

Problem

Multi-chip modules (MCMs) face challenges in maintaining alignment between components, which can lead to misalignment and degrade inter-component communication, and existing technologies struggle to ensure only good semiconductor dies are used, increasing manufacturing costs and complexity.

Innovation Solution

A multi-chip module design incorporating a substrate with a cavity and a compressible structure made of compliant material, which provides a force to maintain the coplanarity of bridge and island chips without bending, using proximity-communication connectors and mechanical features for alignment, facilitating efficient assembly and improved manufacturing yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If remateable components are used to improve manufacturing yield, then bad chips can be swapped out with good ones, but alignment between components becomes difficult to maintain

Engineering Contradiction:
Improvemanufacturing yieldVSAvoidalignment between components
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent uses a flexible membrane structure with compressible material that can accommodate component removal and replacement while maintaining alignment. The membrane's flexibility allows it to deform during chip swapping operations, then return to its original shape to maintain precise alignment between remaining components, resolving the contradiction between remateability and alignment maintenance.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible membrane acts as an intermediary element between the substrate and the chips. It provides a compliant interface that maintains mechanical coupling and alignment while allowing individual chips to be removed and replaced. This intermediary structure enables remateable assembly without compromising the precision alignment between components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If multiple chips are stacked in MCM to increase density, then high-density systems are enabled, but alignment and coplanarity between chips become more difficult to maintain

Engineering Contradiction:
Improvechip densityVSAvoidcoplanarity between chips
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The flexible membrane with compressible material provides a compliant support structure that maintains coplanarity between stacked chips. The membrane can deform to accommodate manufacturing tolerances and thermal expansion differences, ensuring that multiple chips remain properly aligned and coplanar even in high-density configurations.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The compressible material in the flexible membrane changes its physical parameters (compression, expansion) in response to thermal and mechanical stresses. This parameter change allows the membrane to actively maintain coplanarity between chips under varying operating conditions, resolving the alignment difficulties in multi-chip stacks.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If rigid structures are used to maintain alignment, then precise positioning is achieved, but the structure cannot accommodate manufacturing tolerances and thermal expansion

Engineering Contradiction:
Improvealignment precisionVSAvoidtolerance to manufacturing variations
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The flexible membrane replaces rigid support structures with a compliant film that maintains alignment precision while accommodating manufacturing tolerances and thermal expansion. The membrane's flexibility allows it to deform elastically in response to dimensional variations, maintaining coplanarity without requiring extremely tight manufacturing controls.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The membrane structure combines flexible substrate material with compressible material to create a composite structure that provides both mechanical support and compliance. This composite design maintains alignment precision while accommodating thermal and manufacturing variations, resolving the contradiction between rigidity and adaptability.

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design ensures accurate alignment and coplanarity of chips, enhancing communication and manufacturing efficiency, reducing costs by allowing for the use of remateable components and improving the integration of multiple chips in MCMs.

Implementation Method 1

The compressible structure includes a compliant material with shape and volume compression, and the compressible structure provides a force on the bridge chip so that the second surface and the third surface are approximately coplanar without bending the bridge chip

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2815429B1Multi-chip module comprising a compressible structure and method for maintaining alignment in a multi-chip module using a compressible structure
Publication Date: 2021.07.07 ORACLE INT CORP
  • EP2815429B1 patent drawingFigure 1
  • EP2815429B1 patent drawingFigure 2
  • EP2815429B1 patent drawingFigure 3~4

AI summary

An MCM includes a two-dimensional array of facing chips, including island chips and bridge chips that communicate with each other using overlapping connectors. In order to maintain the relative vertical spacing of these connectors, compressible structures are in cavities in a substrate, which house the bridge chips, provide a compressive force on back surfaces of the bridge chips. These compressible structures include a compliant material with shape and volume compression. In this way, the MCM may ensure that facing surfaces of the island chips and the bridge chips, as well as connectors on these surfaces, are approximately coplanar without bending the bridge chips.