Optoelectronic Semiconductor Chip Molded Body Housing Volume Reduction

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Solution Overview

Problem

Existing methods for producing surface-mountable optoelectronic components result in a large housing volume to chip volume ratio, making them unsuitable for compact devices like mobile phones and digital cameras where space is limited.

Innovation Solution

A method involving a molded body that encases the optoelectronic semiconductor chip, with mushroom-shaped connection points and a silicate coating for improved adhesion, using a silicone-epoxy hybrid material for the molding compound to enhance mechanical stability and reduce delamination, and incorporating diffuser or radiation-absorbing particles for specific functionalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional housing structures are used for optoelectronic components, then the component provides adequate protection and electrical isolation, but the housing volume to chip volume ratio becomes excessively large

Engineering Contradiction:
Improvehousing volumeVSAvoidprotection and electrical isolation
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent employs a composite structure consisting of a molded body made from molding compound combined with a leadframe structure. The molded body provides environmental protection while the leadframe provides electrical isolation and mechanical support. This composite approach allows the housing volume to be minimized while maintaining adequate protection, as each material performs its specific function optimally without requiring redundant volume.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If the molded body is separated from connection points during singulation, then the connection points are accessible for electrical contacting, but the adhesion between molded body and connection points deteriorates

Engineering Contradiction:
Improveaccessibility of connection pointsVSAvoidadhesion between molded body and connection points
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies different surface treatments to different regions of the connection points. The portions of the connection points that remain embedded in the molded body have surface characteristics optimized for adhesion, while the portions that are exposed provide accessible electrical contacting surfaces. This local differentiation allows the connection points to simultaneously achieve strong adhesion where needed and accessibility where required.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If standard molding compounds are used, then the manufacturing process is simple, but delamination occurs between the molded body and component surfaces

Engineering Contradiction:
Improvemolding process simplicityVSAvoiddelamination resistance
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical composition parameters of the molding compound by incorporating specific additives and adhesion promoters. These compositional changes enhance the chemical bonding between the molded body and the surfaces it encapsulates (semiconductor chip, leadframe, and connection points), thereby preventing delamination while maintaining the overall simplicity of the injection molding process.

Inventive Principle:
Principle #35Parameter changes

4Volume of moving object

If the housing volume is minimized for compact devices, then space efficiency improves, but the mechanical stability and aging properties deteriorate

Engineering Contradiction:
Improvehousing volumeVSAvoidmechanical stability
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent uses a composite system where the molded body material is specifically formulated with enhanced mechanical properties including improved tensile strength, elongation, and resistance to aging. The leadframe structure provides additional mechanical reinforcement and structural integrity. This composite approach allows the overall housing volume to be minimized while the combined materials maintain adequate mechanical stability and aging resistance.

Inventive Principle:
Principle #40Composite materials

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

The approach results in a compact surface-mountable optoelectronic component with low delamination tendency, high mechanical stability, and improved aging properties, suitable for small devices by minimizing the housing volume relative to the chip volume.

Implementation Method 1

a silicate coating for improved adhesion

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

incorporating diffuser or radiation-absorbing particles for specific functionalities

Methodology Applied
Scientific EffectScattering: Scattering

Implementation Method 3

incorporating diffuser or radiation-absorbing particles for specific functionalities

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

Implementation Method 4

using a silicone-epoxy hybrid material for the molding compound to enhance mechanical stability and reduce delamination

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Data Source

PatentEP1920470B1Method for manufacturing a surface-mounted optoelectronic semiconductor device
Publication Date: 2018.04.04 OSRAM OPTO SEMICON GMBH & CO OHG
  • EP1920470B1 patent drawingFigure 1A~1B
  • EP1920470B1 patent drawingFigure 1C
  • EP1920470B1 patent drawingFigure 2A~2B

AI summary

Disclosed is a surface-mounted component comprising an optoelectronic semiconductor chip (1), a molded member (2) that is molded onto the semiconductor chip (1), an assembly area (3) which is formed at least in some points by a surface of the molded member (2), and at least one terminal point (4a, 4b) which is overlapped laterally by the molded member (2) or extends flush with the molded member (2). Also disclosed is a method for producing such a component.