Semiconductor Element Testing via Removable Redistribution Layer

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Solution Overview

Problem

Conventional semiconductor testing methods require costly, finely manufactured probe cards with close probe spacing, which are prone to contamination and maintenance issues, especially for mini and micro LED products with small spacings, leading to increased production costs and inefficiencies.

Innovation Solution

A method utilizing a redistribution layer formed via a yellow light process, allowing probes to contact the layer instead of the semiconductor element, with the layer being removable by dry, wet, or mechanical grinding, enabling the use of cost-effective probe cards and allowing multiple elements to be tested with a single set of probes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a probe card with smaller probe spacing is used to test mini and micro LED products, then the testing capability for small-spaced semiconductor elements is improved, but the manufacturing cost and maintenance cost of the probe card increase significantly

Engineering Contradiction:

Improvetesting capability for small-spaced semiconductor elementsVSAvoidmanufacturing cost and maintenance cost of probe card

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent introduces a redistribution layer as an intermediary between the semiconductor element and the probe card. This layer has larger pitch than the original metal pads, allowing standard probe cards to test mini and micro LED products without requiring costly custom probe cards with small probe spacing. The redistribution layer converts the small-pitch element array into a larger-pitch test interface.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent adds a vertical dimension by forming a redistribution layer on top of the semiconductor element surface. This third-dimensional approach allows the test interface to be decoupled from the element pitch, enabling standard probe cards to access elements through the redistributed connections rather than requiring direct contact at element pitch.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If a probe card with smaller probe spacing is used, then the testing capability for mini and micro LED products is improved, but the probes are prone to contamination and require frequent cleaning or maintenance

Engineering Contradiction:

Improvetesting capability for mini and micro LED productsVSAvoidprobe contamination and maintenance frequency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The redistribution layer serves as a mediator that protects the original metal pads from direct probe contact. Probes contact the redistribution layer instead of the element pads, reducing contamination risk to the critical element interfaces while maintaining testing capability for mini and micro LED products.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If multiple semiconductor elements are tested simultaneously with closely spaced probes, then the testing speed is improved, but the probe card cost and complexity increase

Engineering Contradiction:

Improvetesting speedVSAvoidprobe card cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent creates copied test interfaces through the redistribution layer, where multiple element connections are remapped to larger-spaced probe contact points. This allows parallel testing of multiple elements using standard probe card pitches, achieving high throughput without requiring expensive custom high-density probe cards.

Inventive Principle:

Principle #26Copying

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 reduces production costs by using less expensive probe cards, improves testing speed, and prevents test probe marks on semiconductor elements, while maintaining high test efficiency and yield rates, especially for mini and micro LED products.

Implementation Method 1

using a yellow light process to form a redistribution layer on the semiconductor element to be tested

Methodology Applied

Scientific EffectPhotolithography: Photopolymerisation

Implementation Method 2

the redistribution layer is removed by a dry, wet or mechanical grinding process

Methodology Applied

Scientific EffectMechanical grinding: Abrasion

Data Source

PatentUS11756841B2Method for testing semiconductor elements

Publication Date: 2023.09.12 TOPCHANG INTERNATIONAL HOLDING LTD

AI summary

Disclosed is a method for testing a semiconductor element. The method comprises forming at least one redistribution layer on a chip, utilizing the at least one redistribution layer to test an array of semiconductor elements on the chip, and removing the at least one redistribution layer from the chip, wherein the length of each semiconductor element is between 2-150 μm and the width of each semiconductor element is between 2-150 μm.