Ultrathin Optoelectronic Modules via Structured Encapsulation

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Solution Overview

Problem

Existing methods for manufacturing optoelectronic modules, such as proximity sensors, face challenges in achieving optimal performance and minimized dimensions while minimizing cost, as they often compromise between module thickness and performance due to issues like delamination, cracking, and warpage, especially when using materials with different thermal expansion coefficients and polymeric materials that shrink upon curing.

Innovation Solution

The method involves using a clear encapsulation material applied to active optical components, followed by an opaque coating and opaque encapsulation, where the opaque coating is structured to define apertures and the opaque encapsulation is applied to fill trenches, providing mechanical protection and precise alignment, while the clear encapsulation material is shaped to prevent delamination and cracking, and the opaque encapsulation is applied to ensure light tightness and mechanical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a separate aperture-stop wafer is used to achieve precise aperture positioning, then manufacturing precision is improved, but device complexity and module thickness increase

Engineering Contradiction:
Improveaperture positioning precisionVSAvoidmodule structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the aperture stop function with the encapsulation material itself. The encapsulation material is structured to directly form the aperture openings, eliminating the need for a separate aperture-stop wafer. This integration maintains precise aperture positioning while reducing device complexity and module thickness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The encapsulation material serves multiple functions: it provides mechanical support, optical isolation, and directly defines the aperture positions. By making the encapsulation material multi-functional, the patent eliminates the separate aperture-stop component while maintaining precise aperture positioning.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If coating surfaces with aperture stops is used to simplify manufacturing, then ease of manufacture is improved, but reliability deteriorates due to delamination and cracking

Engineering Contradiction:
Improveaperture stop application simplicityVSAvoidcoating integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The aperture stops are merged into the encapsulation material structure rather than being applied as a separate coating. This eliminates the coating-substrate interface that causes delamination and cracking, while maintaining the simplicity of wafer-level manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a structured encapsulation material that combines mechanical support and aperture definition functions. This composite structure eliminates the need for separate coating layers, preventing delamination and cracking while maintaining manufacturing simplicity.

Inventive Principle:
Principle #40Composite materials

3Reliability

If heating is applied to improve adhesion of aperture-stop coating, then reliability is improved, but harmful effects increase due to warpage

Engineering Contradiction:
Improvecoating adhesionVSAvoidmodule warpage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

By merging the aperture stop function into the encapsulation material, the patent eliminates the need for separate coating and heating processes. This prevents warpage caused by thermal expansion differences while maintaining reliable aperture positioning through the structured encapsulation material.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If spacer wafers are used to reduce warpage, then reliability is improved, but device complexity and module thickness increase

Engineering Contradiction:
Improvewarpage reductionVSAvoidwafer stacking complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the encapsulation material, including structural support and aperture definition. This eliminates the need for separate spacer wafers, reducing device complexity and module thickness while maintaining reliability through proper material selection and process control.

Inventive Principle:
Principle #5Merging (Combining)

5Device complexity

If direct contact between wafers is increased to reduce module thickness, then device complexity is reduced, but reliability deteriorates due to increased warpage

Engineering Contradiction:
Improvewafer stacking simplicityVSAvoidwarpage control
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges the encapsulation material with the aperture stop function, creating a unified structure that reduces the number of wafer interfaces. This simplifies the wafer stacking while maintaining reliability by reducing the cumulative warpage effects from multiple material interfaces.

Inventive Principle:
Principle #5Merging (Combining)

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 enables the production of ultrathin, low-footprint optoelectronic modules with precise aperture positioning, reduced delamination and cracking, and enhanced optical isolation, achieving high-yield manufacturing and improved performance.

Implementation Method 1

the clear encapsulation material is shaped to prevent delamination and cracking

Methodology Applied
Scientific EffectMechanical constraint:

Implementation Method 2

the opaque coating is structured to define apertures

Methodology Applied
Scientific EffectPhotolithography:

Implementation Method 3

the opaque encapsulation is applied to ensure light tightness

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Data Source

PatentEP3378096B1Thin optoelectronic modules with apertures and their manufacture
Publication Date: 2021.08.11 HEPTAGON MICRO OPTICS PTE LTD
  • EP3378096B1 patent drawingFigure 1A~1D
  • EP3378096B1 patent drawingFigure 2~4
  • EP3378096B1 patent drawingFigure 5A~5B

AI summary

The wafer-level manufacturing method makes possible to manufacture ultrathin optical devices such as opto-electronic modules. A clear encapsulation is applied to an initial wafer including active optical components and a wafer-size substrate, thereon, a photostructurable opaque coating is produced which includes apertures. Then, trenches are produced which extend through the clear encapsulation and establish side walls of intermediate products. Then, an opaque encapsulation is applied to the intermediate products, thus filling the trenches. Cutting through the opaque encapsulation material present in the trenches, singulated optical modules are produced, wherein side walls of the intermediate products are covered by the opaque encapsulation material.