Laminated Substrate Wiring Layout for Mesa Etching

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Solution Overview

Problem

The existing manufacturing methods for laminated substrates with mesa portions having a trapezoidal cross-section often result in disconnection of metal wiring due to eaves-shaped protrusions, particularly when the wiring is formed directly over these protrusions.

Innovation Solution

A method involving the removal of uncovered wiring layers using an etchant, where the wiring is positioned away from the eaves-shaped portions, and its width is set at least twice or three times the thickness of the wiring, depending on the configuration, to prevent disconnection, even when inclined surfaces are present on both sides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the wiring is formed directly over the eaves-shaped portion, then the wiring can be positioned to follow the substrate contour, but the wiring may become disconnected during etching

Engineering Contradiction:
Improvewiring positionVSAvoidwiring continuity
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent applies preliminary action by positioning the wiring away from the eaves-shaped portion before the etching process begins. This preventive positioning ensures that the wiring is not in the path of the etchant that would otherwise flow down the inclined surface and cause disconnection. The wiring layout is deliberately designed with clearance from the eaves-shaped portion to preemptively avoid the harmful etching effect.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the wiring width is increased to prevent disconnection, then wiring integrity is improved, but the device complexity increases

Engineering Contradiction:
Improvewiring integrityVSAvoidwiring dimension control
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by specifying precise wiring width parameters (at least twice or three times the wiring thickness) depending on the configuration. This quantitative parameter specification provides clear design criteria that balance wiring integrity with manufacturability. The parameter-based approach transforms the complex qualitative problem of wiring design into measurable, controllable dimensions.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the wiring is positioned away from the eaves-shaped portion, then disconnection is prevented, but the wiring area increases

Engineering Contradiction:
Improvewiring connection stabilityVSAvoidwiring layer area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies local quality by differentiating the wiring width requirement based on local configuration. When inclined surfaces are present on both sides of the wiring, a larger width (at least three times the thickness) is specified compared to when only one side has an inclined surface (at least twice the thickness). This localized adaptation optimizes the balance between preventing disconnection and minimizing wiring area.

Inventive Principle:
Principle #3Local quality

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 effectively prevents wiring disconnection by ensuring the wiring is not directly exposed to etching processes that can compromise its integrity, maintaining the structural integrity and functionality of the laminated substrate.

Implementation Method 1

removing a portion of a wiring layer not covered with a resist layer from a laminated substrate with an etchant to form a wiring

Methodology Applied
Scientific EffectChemical etching: Ablation

Data Source

PatentEP4047420B1Method for manufacturing a laminated substrate, laminated substrate and light emitting element substrate with the same
Publication Date: 2023.07.26 FUJIFILM BUSINESS INNOVATION CORP
  • EP4047420B1 patent drawingFigure 1
  • EP4047420B1 patent drawingFigure 2
  • EP4047420B1 patent drawingFigure 3

AI summary

A method for manufacturing a laminated substrate includes removing a portion not covered with a resist layer (256) from a laminated substrate with an etchant to form a wiring (261), the laminated substrate including: a base layer including a mesa portion having a trapezoidal cross section, the mesa portion having a first inclined surface (252) extending downward and outward from a top surface and a second inclined surface (253) having an eaves-shaped portion (253a, along line 253b) protruding outward from the top surface; a wiring layer (254) formed on an upper surface of the base layer; and the resist layer (256) formed on an upper surface of the wiring layer and having a shape corresponding to a shape of the wiring (261), and the wiring is arranged at a position where the wiring covers a whole of the eaves-shaped portion (253a, along line 253b) of the second inclined surface.