Electrooptical Device Backside Cavity Integration

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Solution Overview

Problem

Existing electrooptical devices face challenges in integrating sensitive non-linear optical materials due to their sensitivity to micro-electronics fabrication conditions, limiting the use of materials that could achieve high modulation rates and bit rates in data transmission.

Innovation Solution

The electrooptical device incorporates a cavity through the semiconductor substrate, allowing the non-linear optical material to be inserted from the back side, independent of front side device structure fabrication, thus avoiding aggressive processing conditions and enabling the use of materials like organic polymers for high modulation rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If non-linear optical materials are integrated using standard CMOS fabrication methods, then device integration is achieved, but the sensitive non-linear optical materials are damaged by aggressive processing conditions

Engineering Contradiction:
Improvedevice integrationVSAvoidmaterial stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The device is divided into two separate sides: the front side for CMOS fabrication of electronic components and the back side for integration of the non-linear optical material. This segmentation allows each side to be processed independently under appropriate conditions, preventing the optical material from being damaged by aggressive CMOS processing while still achieving full device integration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The integration approach transitions from a single-sided sequential integration to a dual-sided parallel integration. By utilizing the back side of the substrate as a separate integration dimension, the non-linear optical material can be introduced after front side processing is complete, avoiding exposure to harmful processing conditions while maintaining device integration.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If non-linear optical materials are used, then high modulation rates and bit rates are achieved, but the materials cannot withstand micro-electronics fabrication processing conditions

Engineering Contradiction:
Improvemodulation rateVSAvoidfabrication compatibility
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The front side device structures are fabricated completely before introducing the non-linear optical material on the back side. This preliminary action ensures that all aggressive processing steps are completed before the sensitive optical material is introduced, allowing high-performance materials to be used without fabrication compatibility issues.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of the conventional approach of placing optical materials first and then fabricating electronics on top, this invention inverts the sequence by fabricating electronics on the front side first and then integrating the optical material on the back side. This inversion allows the optical material to benefit from high modulation rates while avoiding fabrication compatibility problems.

Inventive Principle:
Principle #13The other way round (Inversion)

3Manufacturing precision

If non-linear optical material is exposed to aggressive processing conditions, then device structure fabrication is completed, but the optical material properties are degraded

Engineering Contradiction:
Improvedevice structure fabricationVSAvoidoptical material properties
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The non-linear optical material is extracted from the front side processing sequence and placed on the back side, where it is shielded from aggressive processing conditions. This extraction allows complete device structure fabrication on the front side while preserving the optical material properties through back side encapsulation and protection.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This approach allows for the integration of non-linear optical materials that were previously incompatible, enabling higher bit rates and robustness in data transmission with reduced energy consumption and improved long-term stability of the non-linear optical material.

Implementation Method 1

By applying a voltage to completely or partially optically transparent electrodes, an electric field is generated having a strong overlap with an optical mode being in interaction with it, therefore changing the transmission properties of the waveguide

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 2

at least one cavity extends through the semiconductor substrate and connects the active layer on the front side of the semiconductor substrate with the back side of the semiconductor substrate

Methodology Applied
Scientific EffectPhysical cavity structure:

Data Source

PatentEP3506002B1Electrooptical device
Publication Date: 2022.06.08 IHP GMBH INNOVATIONS FOR HIGH PERFORMANCE MICROELECTRONICS LEIBNIZ INSTITUT FÜR INNOVATIVE MIKROELEKTRONIK
  • EP3506002B1 patent drawingFigure 1
  • EP3506002B1 patent drawingFigure 2
  • EP3506002B1 patent drawingFigure 3

AI summary

The invention relates to an electrooptical device, comprising: - a semiconductor substrate having a front side and a back side; - at least one photonic component arranged on the front side of the semiconductor substrate, the photonic component comprising an active layer made of a non-linear optical material; wherein - at least one cavity, extends through the semiconductor substrate and connects the active layer on the front side of the semiconductor substrate with the back side of the semiconductor substrate.