Component Carrier Via Formation by Laser Drilling and Etching

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Solution Overview

Problem

The increasing miniaturization and complexity of component carriers with multiple electronic components pose challenges in efficiently forming vertical through connections that are mechanically robust and electrically reliable, while also effectively managing heat dissipation, especially with conventional laser drilling methods that often result in front-to-backside offsets and excessive overhangs.

Innovation Solution

A method involving laser drilling of blind holes followed by etching to create tapering through holes with minimal overhang, eliminating the need for double-sided laser drilling and enabling efficient filling with conductive media, thereby avoiding offsets and improving mechanical and electrical reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional laser drilling is used to form through holes, then manufacturing speed is improved, but front-to-backside offsets and excessive overhangs occur resulting in poor filling reliability

Engineering Contradiction:

Improvemanufacturing speedVSAvoidhole alignment and overhang control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The through hole formation process is segmented into two distinct stages: first laser drilling to create the initial hole path, then chemical etching to complete the through hole. This segmentation allows each process to optimize for its specific function, avoiding the compromises required when using a single method.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A chemical etching process is introduced as an intermediary step between laser drilling and hole filling. This intermediary process removes the harmful overhang material that would otherwise interfere with reliable via filling, while preserving the benefits of laser drilling speed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If double-sided laser drilling is used to eliminate offsets, then alignment precision is improved, but device complexity and process time increase

Engineering Contradiction:

Improvehole alignmentVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The alignment function is extracted from the drilling process itself and transferred to the etching process. The laser only needs to create an initial path, while the etching process provides the final alignment and geometry control, simplifying the overall system requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using drilling to achieve both speed and precision simultaneously, the approach inverts the sequence: use fast drilling for initial hole creation, then use precise etching for final geometry control. This reverses the conventional wisdom that drilling must provide all hole formation functions.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If excessive overhang is present in laser drilled holes, then manufacturing is simplified, but filling reliability and mechanical integrity deteriorate

Engineering Contradiction:

Improvehole formation simplicityVSAvoidvia filling reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The etching process, which could be seen as an additional manufacturing step, actually converts the harmful effect of laser-induced overhang into a beneficial tapered geometry. The etchant selectively removes material to create the desired hole shape, turning a process limitation into a design advantage.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Volume of moving object

If component carrier size is reduced for miniaturization, then product integration is improved, but heat dissipation becomes more difficult

Engineering Contradiction:

Improvecomponent carrier sizeVSAvoidheat dissipation

Core Design Contradiction:

Volume of moving objectVSTemperature

Solution Approach 1:

The component carrier incorporates a heat sink structure with porous or finned geometry that increases surface area for heat dissipation. This allows effective thermal management in miniaturized devices by creating a high surface-area-to-volume ratio structure.

Inventive Principle:

Principle #31Porous 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

This approach allows for the production of component carriers with zero or minimal overhang, reducing yield loss and enabling the manufacture of small vias and annular rings, enhancing mechanical integrity and electrical connectivity without the need for bridge plating, thus supporting high-reliability and miniaturization in component carriers.

Implementation Method 1

laser drilling a blind hole in a layer stack

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

extending the blind hole to a through hole by etching

Methodology Applied

Scientific EffectEtching:

Data Source

PatentEP4152898A1Forming through hole in component carrier by laser drilling blind hole and extending the latter by etching

Publication Date: 2023.03.22 AT & S AUSTRIA TECHNOLOGIE & SYSTEMTECHNIK AG

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AI summary

A method of manufacturing a component carrier (100), wherein the method comprises laser drilling a blind hole (102) in a layer stack (104), and subsequently extending the blind hole (102) to a through hole (106) by etching.