Porous Elastic Compensation Layer for Chip Height Variations

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Solution Overview

Problem

Existing chip packages face challenges in uniformly distributing clamping force over semiconductor chips, leading to uneven current distribution and potential chip damage, especially when dealing with height differences and uneven surfaces, which complicates stacking and reduces module capability.

Innovation Solution

A chip package incorporating an electrically conductive and elastically deformable compensation layer with a porous structure to uniformly distribute clamping force and compensate for height differences between semiconductor chips, eliminating the need for individual springs or tight mechanical tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If individual spring elements are assigned to each semiconductor chip to compensate for height differences, then uniform clamping force distribution is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveuniform clamping force distributionVSAvoidindividual spring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple individual spring elements are merged into a single compensation layer that provides distributed spring support across multiple chip positions. The compensation layer integrates the function of multiple springs into one component, reducing device complexity while maintaining uniform clamping force distribution through its porous elastic structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The compensation layer serves multiple functions simultaneously: it compensates for height differences between chips, distributes clamping force uniformly, provides electrical conductivity, and offers mechanical compliance. This multi-functional design eliminates the need for separate spring elements for each chip.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If tight mechanical tolerances are enforced to ensure uniform clamping force, then reliability is improved, but manufacturing precision requirements and cost increase

Engineering Contradiction:
Improveuniform clamping force distributionVSAvoidmechanical tolerance requirements
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The compensation layer changes the mechanical parameters of the system by introducing an elastic, compliant element that can deform to accommodate height variations. This transforms the system from one requiring rigid precision to one that tolerates variations through elastic deformation, reducing manufacturing precision requirements while maintaining reliable clamping force distribution.

Inventive Principle:
Principle #35Parameter changes

3Strength

If a rigid compensation layer is used to maintain structural stability, then strength is improved, but adaptability to height differences deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidcompensation for height differences
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The compensation layer is designed as a flexible porous structure that can deform elastically to accommodate height differences between chips. Despite its flexibility, it maintains sufficient structural stability through its material properties and geometry, achieving both adaptability and strength simultaneously.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The compensation layer uses composite material properties combining electrical conductivity with elastic deformability. This allows the layer to maintain structural integrity and electrical functionality while adapting to height variations through elastic deformation.

Inventive Principle:
Principle #40Composite materials

4Adaptability or versatility

If a porous structure is introduced to provide elastic deformability, then adaptability to height differences is improved, but electrical conductivity may deteriorate

Engineering Contradiction:
Improveelastic deformabilityVSAvoidelectrical conductivity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The compensation layer utilizes a porous material structure that provides elastic deformability through the void spaces. The porous structure allows the material to compress and expand while maintaining a connected conductive network, achieving both adaptability and electrical conductivity through optimized pore geometry and material composition.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The compensation layer employs composite material properties where the matrix material provides electrical conductivity while the porous structure provides elastic deformability. This composite approach allows simultaneous achievement of adaptability through pore compression and maintained electrical conductivity through the continuous conductive phase.

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 solution ensures robust stacking, maintains low contact resistance, and extends the lifespan of semiconductor chip modules by uniformly distributing clamping force and accommodating varying chip heights, while maintaining high thermal and electrical conductivity.

Implementation Method 1

the at least one first compensation layer comprises a plurality of pores and is elastically deformable so that the at least one first compensation layer is configured to compensate for height differences between the semiconductor chips

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4064345A1Chip package with porous elastically deformable layer
Publication Date: 2022.09.28 HITACHI ENERGY LTD
  • EP4064345A1 patent drawingFigure 1~4
  • EP4064345A1 patent drawingFigure 5~6
  • EP4064345A1 patent drawing

AI summary

In at least one embodiment, the chip package comprises: - at least one first compensation layer (31) which is electrically conductive, and - a plurality of semiconductor chips (2) arranged on and electrically contacted by the at least one first compensation layer (31), wherein - the at least one first compensation layer (31) comprises a plurality of pores (6), and - the at least one first compensation layer (31) is elastically deformable so that the at least one first compensation layer (31) is configured to compensate for height differences (ΔH) between the semiconductor chips (2).