Via Hole Formation Using Pillar Template and Inkjet Printing

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Solution Overview

Problem

Current hole formation methods in semiconductor and display device manufacturing face challenges such as high costs, low reproducibility, and difficulty in forming fine, high-aspect-ratio holes due to issues with solvent evaporation rates and residue formation, particularly in photolithography and printing techniques.

Innovation Solution

A method involving the application of a pillar-forming liquid to create a pillar, followed by the formation and removal of an insulating film, and subsequent heat treatment to form a via hole with high reproducibility and precision, using an electrostatic attraction type inkjet method for precise droplet placement and thermal deformation to achieve a forward tapered shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If photolithography is used to form fine patterns, then manufacturing precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvefine pattern formation precisionVSAvoidphotolithography device complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the complex photolithography mechanical system with a simpler inkjet printing system that uses controlled liquid deposition and thermal processing to achieve fine pattern formation, thereby reducing device complexity while maintaining manufacturing precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the processing parameters by using controlled solvent evaporation rates and specific heating temperatures to achieve fine pattern formation through inkjet printing, providing an alternative to photolithography that reduces device complexity

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If inkjet method is used to form holes with solvent, then ease of manufacture is improved, but manufacturing precision deteriorates due to evaporation rate issues

Engineering Contradiction:

Improvehole formation easeVSAvoidhole formation precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies a liquid repellent material to the substrate before inkjet printing to pre-establish controlled regions that guide solvent evaporation and liquid flow, ensuring precise hole formation while maintaining ease of manufacture

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a liquid repellent material as an intermediary layer that mediates between the inkjet-deposited solvent and the substrate, controlling solvent distribution and evaporation to achieve both ease of manufacture and high precision hole formation

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If liquid repellent region method is used, then manufacturing precision is improved, but productivity decreases due to additional steps

Engineering Contradiction:

Improvehole formation precisionVSAvoidthroughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent combines the liquid repellent region formation and hole formation processes into a single integrated inkjet printing operation, where the liquid repellent material and patterned material are deposited in one pass, thereby maintaining manufacturing precision while improving productivity

Inventive Principle:

Principle #5Merging (Combining)

4Ease of manufacture

If screen printing is used to form holes, then ease of manufacture is improved, but manufacturing precision deteriorates due to liquid running

Engineering Contradiction:

Improvehole formation easeVSAvoidhole diameter control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces a liquid repellent material as an intermediary that prevents liquid running during screen printing by creating controlled boundaries for liquid flow, thereby maintaining ease of manufacture while improving hole diameter control and manufacturing precision

Inventive Principle:

Principle #24Intermediary (Mediator)

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 efficient and cost-effective formation of fine, high-aspect-ratio via holes with improved reproducibility, suitable for multilayer wiring, semiconductor devices, and display elements, reducing the need for expensive equipment and minimizing environmental impact.

Implementation Method 1

using an electrostatic attraction type inkjet method for precise droplet placement

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Implementation Method 2

subsequent heat treatment to form a via hole with high reproducibility and precision, using thermal deformation to achieve a forward tapered shape

Methodology Applied

Scientific EffectThermal deformation: Thermal Expansion

Data Source

PatentUS8956969B2Hole formation method, multilayer wiring, semiconductor device, display element, image display device, and system containing via hole formed by the hole formation method

Publication Date: 2015.02.17 RICOH CO LTD

AI summary

A hole formation method including applying a pillar-forming liquid to a base material, to thereby form a pillar; applying an insulating film-forming material to the base material on which the pillar has been formed, to thereby form an insulating film; removing the pillar to form an opening in the insulating film; and heat treating the insulating film in which the opening has been formed.