LED Interposer Structure for Integrated Inspection and Defect Separation

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Solution Overview

Problem

Existing display devices face challenges in efficiently manufacturing and inspecting light emitting diodes (LEDs) for next-generation display applications, leading to high process costs and complexity.

Innovation Solution

An interposer structure is developed, comprising a temporary substrate with a common pad and multiple LEDs, where each LED has a specific lamination structure, allowing for simultaneous manufacturing and inspection through electrical connections to a common pad, enabling cost reduction and process simplification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If light emitting diodes are manufactured using conventional separate processes, then manufacturing precision can be maintained, but process complexity and cost increase significantly

Engineering Contradiction:
Improveprocess simplicityVSAvoidprocess complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines the LED manufacturing process and interposer fabrication process into a single integrated process. The LED structure is formed directly on the interposer substrate through sequential lamination of electrodes, semiconductor layers, emission layers, and passivation layers in one continuous manufacturing flow, eliminating the need for separate manufacturing and assembly processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The interposer substrate serves multiple functions simultaneously: it acts as the manufacturing platform for LED structures, provides electrical connections through common pads, enables inspection through probe card integration, and serves as the final mounting substrate. This multi-functionality reduces the number of separate processes and components needed.

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

2Measurement precision

If LED inspection is performed after manufacturing, then manufacturing precision is maintained, but inspection cost and process time increase

Engineering Contradiction:
Improveinspection capabilityVSAvoidprocess time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent incorporates inspection capabilities into the manufacturing process itself. Probe cards are integrated during the manufacturing process to perform electrical and optical inspections of LED structures while they are still on the interposer substrate, before final assembly. This allows for real-time quality control without adding separate inspection steps.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If defective LEDs are identified and separated, then product quality improves, but additional process steps are required

Engineering Contradiction:
Improveproduct qualityVSAvoidprocess efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The integrated manufacturing and inspection system automatically identifies defective LED structures through real-time monitoring during manufacturing. The system self-corrects by preventing defective structures from proceeding to subsequent steps, eliminating the need for separate manual inspection and sorting processes.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4611508A1Interposer including light emitting diode, method for manufacturing interposer including light emitting diode, and method for inspecting light emitting diode
Publication Date: 2025.09.03 LG DISPLAY CO LTD
  • EP4611508A1 patent drawingFigure 1A~1B
  • EP4611508A1 patent drawingFigure 2A~2B
  • EP4611508A1 patent drawingFigure 3A~3B

AI summary

An interposer (100, 400) may include a temporary substrate (Sub), a common pad (PAD) disposed on the temporary substrate (Sub) and light emitting diodes (ED1, ED2) disposed on the common pad (PAD). Each of the light emitting diodes (ED1, ED2) may include a first electrode (124, 424), a first semiconductor layer (121), an emission layer (122), a second semiconductor layer (123), a second electrode (125), and a passivation layer (127, 427). The second electrode (125), the second semiconductor layer (123), the emission layer (122), the first semiconductor layer (121) and the first electrode (124, 424) may have a structure formed from sequential lamination. The passivation layer (127, 427) may enclose the second semiconductor layer (123), the emission layer (122) and the first semiconductor layer (121). The common pad (PAD) may be electrically connected to the second electrode (125) at a lower side of the light emitting diodes (ED1, ED2). The first electrode (124, 424) in each of the light emitting diodes (ED1, ED2) may extend to an upper portion of the passivation layer (127, 427). A method for inspecting light emitting diodes (ED1, ED2) disposed on a temporary substrate (Sub) is also disclosed.