Semiconductor Chip Screen Printing Mask for Contact Protection

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Solution Overview

Problem

Existing methods for manufacturing radiation-emitting semiconductor devices face challenges in achieving efficient manufacturing processes that preserve the integrity of electrical contacts and minimize the need for complex cleaning steps, often resulting in the removal and reapplication of solderable metallization.

Innovation Solution

A method involving the use of an auxiliary carrier with spacers and a reflective casting compound applied using screen printing or squeegees, where the casting compound does not cover the rear sides or second main surfaces of electrical contacts, allowing for easy cleaning and preserving the solderable coating, and the application of a wavelength-converting layer to enhance radiation emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a casting compound is applied to the rear side of semiconductor chips using conventional methods, then the chips are encapsulated and protected, but the electrical contacts are covered and require complex cleaning steps to remove the casting compound

Engineering Contradiction:

Improveintegrity of electrical contactsVSAvoidcleaning complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces a mask structure that segments the application area of the casting compound, allowing it to be applied only to specific regions (front side and side surfaces of chips) while excluding the electrical contacts on the rear side. This segmentation enables selective coating without covering the contacts, eliminating the need for complex cleaning steps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mask is applied beforehand to the semiconductor chip array before the casting compound is applied. This preliminary action defines the application boundaries and protects the electrical contacts in advance, so that when the casting compound is applied, it automatically excludes the contact areas without requiring subsequent removal or cleaning operations.

Inventive Principle:

Principle #10Preliminary action

2Strength

If the casting compound is applied to completely encapsulate the semiconductor chips, then mechanical protection is improved, but the electrical contacts become inaccessible and require removal of the coating

Engineering Contradiction:

Improvemechanical protection of semiconductor chipsVSAvoidaccessibility of electrical contacts

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The mask enables local quality control by allowing the casting compound to be applied with different properties to different regions: the front side and side surfaces receive full encapsulation for mechanical protection, while the rear side with electrical contacts remains free of the compound, maintaining electrical accessibility and solderability.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If conventional application methods are used to apply casting compound, then complete coverage is achieved, but the solderable metallization on electrical contacts must be removed and reapplied

Engineering Contradiction:

Improvecoverage of casting compoundVSAvoidmetallization processing steps

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The mask structure extracts or excludes the electrical contact regions from the casting compound application area. By defining the application boundaries through the mask, the method takes out the contacts from the coating process entirely, preserving the solderable metallization and eliminating the need for its removal and reapplication.

Inventive Principle:

Principle #2Taking out (Extraction)

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 method enables the production of radiation-emitting semiconductor devices with improved efficiency by maintaining the integrity of electrical contacts and reducing the need for complex cleaning, while enhancing light emission through the use of a wavelength-converting layer and reflective casting compound.

Implementation Method 1

a wavelength-converting layer is applied to the main surface of the semiconductor chip assembly on which the auxiliary carrier was applied

Methodology Applied

Scientific EffectWavelength conversion: Photoluminescence

Implementation Method 2

a casting compound is applied between the semiconductor chips by means of screen printing or squeegees in such a way that a semiconductor chip assembly is formed... a reflective casting compound

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS11616178B2Method for producing a plurality of radiation-emitting semiconductor devices with a screen for a screen printing process

Publication Date: 2023.03.28 OSRAM OLED

AI summary

A method for producing a plurality of radiation emitting semiconductor devices and a radiation emitting semiconductor device are disclosed. In an embodiment a method include providing an auxiliary carrier, applying a plurality of radiation-emitting semiconductor chips to the auxiliary carrier with front sides so that rear sides of the semiconductor chips are freely accessible, wherein each rear side of the respective semiconductor chip has at least one electrical contact, applying spacers to the auxiliary carrier so that the spacers directly adjoin side surfaces of the semiconductor chips and applying a casting compound between the semiconductor chips by a screen printing process such that a semiconductor chip assembly is formed, wherein a screen for the screen printing process has a plurality of cover elements, and wherein each cover element covers at least one electrical contact.