Integrated Waveguide Metallic Elements for CMOS Light Redirection

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Solution Overview

Problem

Conventional image sensor technologies, particularly CMOS image sensors, face challenges in optimizing optical efficiency due to the geometric arrangement of photodetectors with respect to other pixel structure elements, as standard geometrical optics models fail to accurately predict light propagation at deep sub-micron scales, where electromagnetic interactions with metallic elements become significant.

Innovation Solution

The implementation of an integrated waveguide using electromagnetic field simulation techniques, which positions metallic elements within the dielectric structure to redirect light towards the photodetector, optimizing the electromagnetic field distribution and enhancing optical efficiency by simulating the interaction between incident light and the pixel structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If standard geometrical optics models are used to design pixel structure, then design process is simple, but light propagation prediction is inaccurate at deep sub-micron scales

Engineering Contradiction:

Improvedesign process simplicityVSAvoidlight propagation prediction accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transitions from geometrical optics parameters to electromagnetic field parameters to accurately model light behavior at deep sub-micron scales where wavelength effects become significant

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces geometrical optics modeling with electromagnetic field simulation to accurately predict light propagation in deep sub-micron pixel structures

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If metallic elements are positioned to optimize electromagnetic field distribution, then optical efficiency is improved, but device complexity increases

Engineering Contradiction:

Improveoptical efficiencyVSAvoidpixel structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent converts the potentially harmful light-blocking effect of metallic elements into a beneficial effect by strategically positioning them to manipulate electromagnetic field distribution and redirect light toward the photodetector

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent uses electromagnetic field simulation as an intermediary tool to optimize the positioning of metallic elements, allowing indirect optimization of light propagation without direct mechanical adjustment

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If pixel elements are scaled to deep sub-micron dimensions, then device integration is improved, but conventional optics modeling becomes inadequate

Engineering Contradiction:

Improvedevice integrationVSAvoidoptics modeling accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent changes the modeling approach from geometrical optics to electromagnetic field simulation to maintain accuracy as pixel dimensions approach wavelength scales

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent adds the electromagnetic field dimension to the modeling approach, moving beyond three-dimensional geometrical optics to include wave nature of light in deep sub-micron structures

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 improves optical efficiency by redirecting light that would otherwise be non-incident on the photodetector, leading to higher light sensitivity and image quality, counteracting conventional design limitations by intentionally placing metallic elements in close proximity to the photodetector.

Implementation Method 1

The integrated waveguide includes a dielectric structure configured to receive a first electromagnetic field distribution via a first major surface and has a second major surface, wherein the first electromagnetic field distribution produces a second electromagnetic field distribution within the dielectric structure

Methodology Applied

Scientific EffectElectromagnetic field distribution: Electromagnetic Induction

Implementation Method 2

The at least one metallic element structured and positioned to effect the second electromagnetic field distribution to increase an amount of the second electromagnetic field distribution that is incident upon a selected region of the second major surface

Methodology Applied

Scientific EffectLight redirection: Reflection

Data Source

PatentUS7616855B2Integrated waveguide and method for designing integrated waveguide

Publication Date: 2009.11.10 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

An integrated waveguide including a dielectric structure configured to receive a first electromagnetic field distribution via a first major surface and having a second major surface, wherein the first electromagnetic field distribution produces a second electromagnetic field distribution within the dielectric structure. The waveguide further includes at least one metallic element disposed in the dielectric structure between the first major surface and the second major surface, the at least one metallic element structured and positioned to effect the second electromagnetic field distribution to increase an amount of the second electromagnetic field distribution that is incident upon a selected region of the second major surface.