3D Functional Block Stacking Without CMP Edge Damage

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current 3D assembly technologies in microelectronics face challenges in scalability, edge degradation, and reliability due to chemical-mechanical polishing (CMP) processes, leading to complex and incompatible assembly of substrates and chips with varying materials, sizes, and designs.

Innovation Solution

A 3D assembly process involving planarized functional blocks with copper interconnection layers, allowing direct bonding and transfer onto a receiving substrate, enabling stacking of multiple blocks without edge effects and improving mechanical strength and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If chemical-mechanical polishing (CMP) is used for planarization in 3D assembly, then surface flatness is improved, but edge degradation and intra-layer microcracks occur

Engineering Contradiction:
Improvesurface flatnessVSAvoidedge degradation and microcracks
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent extracts and removes the problematic CMP planarization step from the 3D assembly process. Instead of using CMP to achieve surface flatness, the invention directly bonds planarized surfaces without the harmful polishing process, thereby eliminating edge degradation and intra-layer microcracks while maintaining surface flatness requirements

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary planarization process that achieves surface flatness without the harmful effects of CMP. This intermediary process serves as a mediator between the need for flat surfaces and the avoidance of edge degradation, enabling direct bonding without traditional CMP steps

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If direct bonding is used for 3D assembly, then manufacturing complexity is reduced, but scalability to large numbers of assemblies is limited

Engineering Contradiction:
Improveassembly process complexityVSAvoidscalability to large numbers of assemblies
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent segments the 3D assembly process into modular functional blocks that can be independently prepared and then systematically stacked. This segmentation enables scalability by allowing parallel processing of multiple blocks and their subsequent assembly into large-scale 3D structures without proportionally increasing process complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary planarization and preparation of functional blocks before the actual bonding process. This preliminary action enables more assemblies to be prepared in advance, facilitating scalable production where multiple pre-prepared blocks can be rapidly stacked without increasing the complexity of the core bonding process

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If multiple functional blocks are stacked vertically, then integration density is improved, but edge effects accumulate making further stacking difficult

Engineering Contradiction:
Improveintegration densityVSAvoidedge effects
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent extracts and eliminates the source of edge effects by removing the CMP process from each stacking step. Without CMP-induced edge degradation, functional blocks can be stacked multiple times without accumulating edge effects, enabling sustained high integration density across many layers

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent treats the donor substrate as a disposable temporary carrier that is removed after transferring the functional block. This approach allows each functional block to be independently prepared and transferred without permanent edge effects on the final assembly, enabling continuous stacking of fresh blocks

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 process facilitates easy implementation of 3D assemblies with high integration density and improved performance by avoiding edge degradation and intra-layer microcracks, supporting diverse stacking variants and materials.

Implementation Method 1

The conductive elements 112 of the first interconnection layer 110 of the first functional block 100 are facing and in contact with the conductive elements 122 of the second interconnection layer 120 of the second functional block 200

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

transfer, successively, onto a recipient substrate the functional blocks by direct bonding

Methodology Applied
Scientific EffectDirect bonding: Welding

Data Source

PatentEP4709136A1Method for producing a 3D connection
Publication Date: 2026.03.11 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4709136A1 patent drawingFigure 1A~1E
  • EP4709136A1 patent drawingFigure 2A~3F
  • EP4709136A1 patent drawingFigure 4A~4L

AI summary

This description relates to a process comprising the following steps: - providing several assemblies, each comprising a donor substrate (10) covered by a functional block (100, 200) successively comprising a first interconnecting layer (110), a functional layer (130) and a second interconnecting layer (120), the functional layer comprising one or more electronic components, the interconnecting layers (110, 120) comprising a dielectric material (111, 121) in which conductive elements (112, 122) are formed, a first surface of the first interconnecting layer (110) in contact with the donor substrate (10) and the free surface of the second interconnecting layer (120) being planarized so as to be compatible with subsequent direct bonding, - transferring, successively, onto a receiving substrate (20) the functional blocks (100, 200), by direct bonding,to form a 3D assembly comprising a receiving substrate (20) covered by a stack of two functional blocks (100, 200).