Color Filter Cavity Adhesion via Local Quality Zones

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Solution Overview

Problem

The formation of color filters in microelectronic imaging devices using photolithographic methods often results in incorrect definition of filtering elements at the periphery and adhesion issues near vertical walls, especially when trying to achieve correct definition both inside and outside a cavity.

Innovation Solution

A method involving thin layers of color filters with filtering elements of different critical dimensions in distinct regions, separated by zones of different materials, to prevent adhesion loss and ensure correct definition, with filtering elements arranged in a Bayer pattern and optionally accompanied by microlenses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photolithographic method is used to define resin blocks for color filter, then filtering elements can be formed, but adhesion loss occurs near vertical walls of the cavity

Engineering Contradiction:

Improvedefinition of filtering elementsVSAvoidadhesion of resin

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent introduces intermediate zones with specific materials between the filtering elements and the cavity walls. These zones are located specifically where adhesion problems occur (near vertical walls), providing local adhesion enhancement without affecting other regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses intermediate zones composed of specific materials as mediators between the resin blocks and the cavity walls. These intermediate materials improve adhesion at the critical interface where adhesion loss was occurring, resolving the reliability issue.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If dummy filtering elements are added at the periphery, then adhesion issues may be mitigated, but device complexity increases

Engineering Contradiction:

Improveadhesion of resinVSAvoidstructure of color filter

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of adding dummy elements throughout the periphery, the patent applies local quality enhancement only where needed: intermediate zones are placed specifically between filtering elements and cavity walls. This targeted approach improves adhesion without unnecessarily increasing device complexity.

Inventive Principle:

Principle #3Local quality

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 successful formation of color filters with precise dimensions and reduced adhesion loss near cavity walls, enhancing the accuracy and reliability of microelectronic imaging devices.

Implementation Method 1

filtering elements of a first type, based at least on a first material and respectively capable of filtering a first range of wavelengths from the visible luminous spectrum

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

the resin or the polymer is exposed, for example, using UV radiation through a mask. After exposure, the resin is developed.

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS8138012B2Production of an improved color filter on a microelectronic imaging device comprising a cavity

Publication Date: 2012.03.20 STMICROELECTRONICS FRANCE

AI summary

A microelectronic device includes a color filter equipped with a plurality of filtering elements, including several filtering elements. The device includes at least one first zone located inside a cavity and includes a first group of filtering elements having a first critical dimension, and at least one second zone at the periphery of the cavity, including a second group of filtering elements having a second critical dimension that is different from the first critical dimension.