Hydrophobic Image Sensor Insulating Layers

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Solution Overview

Problem

Image sensors face challenges in improving light-collection efficiency due to hydrophilic surfaces on insulating layers, which can lead to moisture-related defects and reduced picture quality, especially in humid environments.

Innovation Solution

The surfaces of insulating layers and interlayer insulating layers exposed by cavities are modified to be hydrophobic through plasma processing using gases like ammonia (NH3), nitrogen (N2), carbon tetrafluoride (CF4), sulfur hexafluoride (SF6), or nitrogen trifluoride (NF3), eliminating polar molecules and enhancing moisture resistance without additional protective layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If hydrophilic surfaces are used on insulating layers, then manufacturing is simpler, but moisture resistance deteriorates leading to defects in humid environments

Engineering Contradiction:

Improvesurface treatment processVSAvoidmoisture resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the surface energy parameter of the insulating layer by forming a hydrophobic surface layer with lower surface energy than the bulk insulating material. This is achieved through specific material selection and surface treatment processes that reduce surface energy, creating moisture-resistant properties without complicating the overall manufacturing process.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure where a hydrophobic surface layer is formed on top of the insulating layer. This composite approach combines the electrical insulation properties of the base material with the moisture resistance of the hydrophobic surface layer, achieving both reliability and ease of manufacture.

Inventive Principle:

Principle #40Composite materials

2Reliability

If additional protective layers are formed to improve moisture resistance, then reliability improves, but device complexity and manufacturing steps increase

Engineering Contradiction:

Improvemoisture resistanceVSAvoidnumber of layers

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the protective function with the insulating layer itself by forming the hydrophobic surface layer as an integral part of the insulating structure. This eliminates the need for separate protective layers, reducing device complexity while maintaining moisture resistance and reliability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The hydrophobic surface layer serves multiple functions: it provides moisture resistance, maintains electrical insulation properties, and can contribute to light transmission optimization. This multi-functionality reduces the need for additional specialized layers, simplifying the overall device structure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If hydrophobic surfaces are formed through plasma processing, then moisture resistance improves, but processing time and energy consumption increase

Engineering Contradiction:

Improvemoisture resistanceVSAvoidplasma processing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies plasma processing in a controlled manner, using partial action sufficient to create the hydrophobic surface layer without excessive treatment. This optimizes the balance between achieving adequate moisture resistance and minimizing processing time and energy consumption.

Inventive Principle:

Principle #16Partial or excessive action

4Productivity

If cavities are formed to expose insulating layer surfaces, then light collection efficiency improves, but surface area exposed to moisture increases

Engineering Contradiction:

Improvelight collection efficiencyVSAvoidmoisture exposure

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by forming the hydrophobic surface layer on the cavities before they are exposed to the environment. This pre-protection prevents moisture from entering the cavities and affecting the underlying structures, allowing the cavities to maintain their light collection function without increased moisture vulnerability.

Inventive Principle:

Principle #9Preliminary anti-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

This approach improves light-collection efficiency and moisture resistance, reducing defects and maintaining high picture quality, while simplifying the manufacturing process by avoiding the need for additional protective layers and minimizing energy-related dark current issues.

Implementation Method 1

Methodology Applied

Scientific EffectPlasma processing: Plasma

Data Source

PatentUS9117716B2Image sensors including hydrophobic interfaces and methods of fabricating the same

Publication Date: 2015.08.25 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of fabricating an image sensor device includes forming an insulating layer on a substrate including a photodiode therein, and forming a wiring structure on the insulating layer. The wiring structure includes at least one wiring layer and at least one insulating interlayer. A cavity is formed extending into the wiring structure over the photodiode to expose a surface of the at least one insulating interlayer. The surface of the at least one insulating interlayer exposed by the cavity is modified to define a hydrophobic surface. Related systems and devices are also discussed.