Circuit Forming Method Using Overlapping Metal Coatings

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Solution Overview

Problem

Existing methods for forming circuits using metal-containing liquids and pastes face challenges in achieving conductivity while minimizing mechanical deterioration of the resin laminate due to prolonged and high-temperature heating processes.

Innovation Solution

A circuit forming method involving the collective heating of metal-containing liquid and metal paste, where the metal-containing liquid contains fine metal particles and the metal paste contains larger metal particles and a resin binder, applied in an overlapping manner on a base, allowing for simultaneous firing and conductivity achievement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the metal-containing liquid and metal paste are heated separately in conventional steps, then the circuit can be formed with adequate conductivity, but the heating time and temperature increase, causing mechanical deterioration of the resin laminate

Engineering Contradiction:

ImproveconductivityVSAvoidmechanical deterioration of resin laminate

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent combines the heating processes for the metal-containing liquid and metal paste into a single simultaneous heating step. Both materials are heated together at the same temperature for the same duration, eliminating the need for separate heating cycles. This merging of processes reduces total heating time and cumulative thermal exposure to the resin laminate, thereby minimizing mechanical deterioration while still achieving adequate conductivity in both materials.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If the heating process is extended to ensure complete conductivity of both metal-containing liquid and metal paste, then conductivity is improved, but the processing time increases

Engineering Contradiction:

ImproveconductivityVSAvoidheating time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the heating operations for different materials into a single concurrent process. By heating the metal-containing liquid and metal paste simultaneously at the same temperature, the total processing time is reduced compared to sequential heating, while both materials achieve the necessary conductivity within the same time frame.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent optimizes the heating temperature and time parameters to achieve a balance between conductivity development and processing efficiency. By carefully selecting the heating temperature and duration, the process achieves adequate conductivity in both materials within a reduced time frame, avoiding excessive heating time while ensuring proper circuit formation.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If high temperature heating is applied to make the metal paste conductive, then conductivity is achieved, but the resin laminate suffers mechanical deterioration

Engineering Contradiction:

Improveconductivity of metal pasteVSAvoidmechanical strength of resin laminate

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent carefully selects and controls the heating temperature parameter to achieve conductivity in the metal paste while staying below temperatures that would cause severe damage to the resin laminate. By optimizing this critical parameter, the process achieves the necessary electrical conductivity without excessive thermal damage to the mechanical structure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

By combining the heating of metal-containing liquid and metal paste into a single process step, the patent reduces the cumulative thermal exposure time to the resin laminate. This minimized heating duration at elevated temperature reduces mechanical deterioration while still achieving the required conductivity in the metal paste.

Inventive Principle:

Principle #5Merging (Combining)

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 the heating time and temperature required for the resin laminate, minimizing mechanical deterioration and shortening the circuit formation cycle while maintaining adequate conductivity, with a slight increase in resistance values that are still practical for use.

Implementation Method 1

a heating step of heating the metal-containing liquid and the metal paste so that the metal-containing liquid and the metal paste, being coated in the coating step, become conductive

Methodology Applied

Scientific EffectSintering: Sintering

Implementation Method 2

heating the metal-containing liquid and the metal paste so that the metal-containing liquid and the metal paste, being coated in the coating step, become conductive

Methodology Applied

Scientific EffectThermal decomposition: Pyrolysis

Data Source

PatentUS11570900B2Circuit forming method

Publication Date: 2023.01.31 FUJI CORP

AI summary

A circuit forming method, comprising: a coating step of applying a metal-containing liquid and a metal paste in an overlapping manner on a base, the metal-containing liquid containing fine metal particles and the metal paste containing a resin binder and metal particles larger than the fine metal particles in the metal-containing liquid; and a heating step of making the metal-containing liquid and the metal paste coated in the coating step conductive by heating the metal-containing liquid and the metal paste.