Low Surface Roughness Metal Foil Circuit Pattern Formation

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Solution Overview

Problem

Existing semi-additive processes for forming circuit patterns on substrates face challenges in ensuring sufficient adhesion of the copper seed layer to the insulating base, particularly due to the non-uniform roughness of the insulating base, which affects the formation of microcircuits.

Innovation Solution

A method involving the use of a thin metal foil with low surface roughness, featuring flat-topped projections, is bonded onto the insulating base to transfer its surface roughness. This enhances the adhesion between the metal foil and the insulating base, facilitating the formation of a circuit pattern through electroless plating and electroplating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electroless copper plating is performed on the insulating base to form a copper seed layer, then the circuit pattern can be formed, but sufficient adhesion to the insulating base cannot be ensured

Engineering Contradiction:

Improveadhesion of copper seed layer to insulating baseVSAvoiddifficulty in ensuring sufficient adhesion

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The insulating base surface is roughened before electroless copper plating to create a favorable surface structure in advance. This preliminary surface preparation ensures that when the copper seed layer is formed, it can adhere sufficiently to the insulating base, resolving the adhesion problem without requiring complex additional steps during the plating process itself

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the surface of the insulating base is roughened to ensure adhesion, then adhesion is improved, but the non-uniform roughness makes it difficult to form microcircuits

Engineering Contradiction:

Improveadhesion to insulating baseVSAvoiduniformity of surface roughness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The surface roughening is performed selectively and uniformly across the entire insulating base surface to create consistent local characteristics. By controlling the roughening process to produce uniform micro-roughness features throughout the surface, the patent achieves both sufficient adhesion and the uniformity needed for precise microcircuit formation, avoiding the non-uniformity problem of conventional roughening methods

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

The method ensures sufficient adhesive strength to the insulating base, allowing for the formation of circuit patterns at a lower cost while improving process control and enabling the creation of microcircuit patterns with enhanced uniformity and reliability.

Implementation Method 1

bonding a metal foil having one or more flat-topped projections onto the insulating base, and transferring the surface roughness of the metal foil to the insulating base

Methodology Applied

Scientific EffectSurface roughness transfer:

Implementation Method 2

electroless copper plating is performed

Methodology Applied

Scientific EffectElectroless plating:

Implementation Method 3

copper electroplating is then performed to form a circuit pattern

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS20250031316A1Methods for forming circuit pattern on substrate using metal foil with low surface roughness

Publication Date: 2025.01.23 YMT CO LTD

AI summary

Provided are methods for forming a circuit pattern on a substrate by a process for circuit pattern formation, such as a semi-additive process (SAP) or a modified semi-additive process (mSAP), using a thin metal foil with low surface roughness.