Isolation Structure With Etch Vias for Micro-Transfer Printing

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Solution Overview

Problem

Existing methods for transferring small integrated circuits from a semiconductor wafer to a destination substrate, such as glass or plastic, are inefficient, costly, and prone to process difficulties, particularly in forming robust releasable integrated circuits suitable for micro-transfer printing.

Innovation Solution

A semiconductor structure is developed with a patterned insulation layer and etch vias, surrounded by isolation material, allowing for the formation of tethers that connect the integrated circuits to an anchor, enabling efficient and cost-effective micro-transfer printing by reducing the number of processing steps and enhancing the robustness of the devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional lithography is used to pattern small features, then manufacturing precision can be achieved, but the process becomes impractical and costly for sub-10nm features

Engineering Contradiction:
Improvefeature size precisionVSAvoidmanufacturing practicality
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces conventional lithography (optical/mechanical system) with a self-assembly approach using block copolymers that spontaneously form nanoscale patterns through thermodynamic self-organization. This eliminates the need for complex lithographic equipment and processes to achieve sub-10nm features, making manufacturing more practical while maintaining or improving precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter from top-down lithographic patterning to bottom-up self-assembly. By controlling polymer composition, molecular weight, and annealing conditions, the system naturally forms desired patterns without requiring progressively more complex and expensive lithographic tools as feature sizes decrease.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If materials are released from a substrate for transfer printing, then device integration flexibility is improved, but adhesion control becomes challenging

Engineering Contradiction:
Improvedevice integration flexibilityVSAvoidadhesion control
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs dynamic adhesion control where the substrate provides temporary strong adhesion during fabrication, then releases the patterned material upon heating above the glass transition temperature. This dynamic behavior enables both reliable adhesion during manufacturing and controlled release for transfer printing, resolving the contradiction between adhesion control and integration flexibility.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes the glass transition phase transition of the polymer material. Below Tg, the material is rigid and adheres strongly to the substrate. Above Tg, the material becomes rubbery and releases from the substrate, enabling transfer printing. This phase transition provides reliable adhesion control while maintaining integration flexibility.

Inventive Principle:
Principle #36Phase transitions

3Manufacturing precision

If micropatterning is performed before material deposition, then manufacturing precision is improved, but process complexity increases

Engineering Contradiction:
Improvepattern alignmentVSAvoidprocess steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the patterning step and material deposition step into a single self-assembly process. The block copolymer simultaneously defines the pattern and serves as the material to be deposited, eliminating the need for separate lithography and deposition steps while maintaining manufacturing precision and reducing process complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent performs preliminary self-assembly of the block copolymer on the substrate before any material deposition or device fabrication. This pre-formed pattern serves as a template that guides subsequent processing steps, ensuring manufacturing precision while simplifying the overall process by establishing the pattern early in a single step.

Inventive Principle:
Principle #10Preliminary action

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 method allows for higher resolution tethers, more robust semiconductor devices, and increased density on the wafer, reducing processing complexity and costs while ensuring environmental and electrical protection.

Implementation Method 1

The polymer matrix may be any polymer that provides adhesion to a microelectromechanical device

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

a release agent layer is formed over the microelectromechanical device and the second portion of the polymer matrix

Methodology Applied
Scientific EffectRelease agent:

Implementation Method 3

heating the microelectromechanical device above a glass transition temperature of the polymer matrix

Methodology Applied
Scientific EffectGlass transition:

Data Source

PatentEP3555912B1Isolation structure for micro-transfer-printable devices
Publication Date: 2026.02.04 X FAB SEMICONDUCTORS FOUNDRIES AG
  • EP3555912B1 patent drawingFigure 1A~1B
  • EP3555912B1 patent drawingFigure 2A~2B
  • EP3555912B1 patent drawingFigure 3A~3B

AI summary

A semiconductor structure suitable for micro-transfer printing comprises a semiconductor substrate and a patterned insulation layer disposed on or over the semiconductor substrate. The insulation layer pattern forms one or more etch vias in contact with the semiconductor substrate. In some embodiments, each etch via is exposed. A semiconductor device is disposed on the patterned insulation layer and is surrounded by an isolation material in one or more isolation vias that are adjacent to the etch via. The etch via can be at least partially filled with a semiconductor material that is etchable with a common etchant as the semiconductor substrate. In some embodiments, the etch via is empty and the semiconductor substrate is patterned to forma gap that separates at least a part of the semiconductor device from the semiconductor substrate and forms a tether physically connecting the semiconductor device to an anchor (e.g., a portion of the semiconductor substrate or the patterned insulation layer).