Aluminum Oxide Film on Semiconductor Device

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Solution Overview

Problem

The existing bonding wire connection method between a semiconductor chip and a lead frame faces reliability issues due to inadequate adhesion, often resulting in easy separation and corrosion, especially when a thick fluorine-containing film is present between the bonding wire and the aluminum layer.

Innovation Solution

A semiconductor device is manufactured with a semiconductor substrate, a first insulating layer, an aluminum layer, a second insulating layer covering a portion of the aluminum layer, and an aluminum oxide film with α-alumina as the main component, where the film thickness is between 0.5 nm and 3 nm, and a cleaning process using a liquid with pH 6 or higher to 7.5 is performed to remove the fluorine-containing film, enhancing adhesion by direct connection of the bonding wire to the aluminum layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a thick fluorine-containing film is present between the bonding wire and the aluminum layer, then the manufacturing process is simpler, but the adhesion between the bonding wire and the aluminum layer deteriorates

Engineering Contradiction:

Improveease of manufactureVSAvoidadhesion between bonding wire and aluminum layer

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by performing a cleaning process before bonding wire connection to remove the fluorine-containing film from the aluminum layer surface. This preliminary removal of the harmful film ensures that when the bonding wire is subsequently connected, there is no barrier to adhesion, thus solving the contradiction between manufacturing simplicity and bonding reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of the fluorine-containing film (which prevents adhesion) into a beneficial process step. By intentionally introducing the film during manufacturing and then systematically removing it through cleaning, the process transforms a potential defect into a controlled intermediate state that, when removed, reveals the high-adhesion aluminum surface for reliable bonding

Inventive Principle:

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

2Productivity

If the aluminum layer surface is not cleaned, then the manufacturing process is faster, but the bonding wire connection reliability deteriorates due to easy separation and corrosion

Engineering Contradiction:

Improvemanufacturing speedVSAvoidbonding wire connection reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The cleaning process is performed as a preliminary step before bonding wire connection, removing the fluorine-containing film in advance. This ensures that when bonding occurs, the aluminum surface is already prepared for optimal adhesion, preventing future separation and corrosion issues while maintaining manufacturing efficiency

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent transforms the potentially harmful fluorine-containing film into a beneficial process feature. The film is intentionally formed during manufacturing, then systematically removed through cleaning to reveal the high-adhesion aluminum surface, converting what would be a defect into a controlled intermediate state that enhances final bonding reliability

Inventive Principle:

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

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 improves the adhesion between the bonding wire and the aluminum layer, reducing the risk of separation and corrosion, thereby enhancing the reliability of the semiconductor device by forming a thin, stable aluminum oxide film that prevents electrostatic breakdown and maintains the quality of the aluminum oxide film.

Implementation Method 1

an aluminum oxide film formed on a surface of the aluminum layer, the aluminum oxide film including α-alumina as a main component

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

a cleaning process using a liquid with pH 6 or higher to 7.5 is performed to remove the fluorine-containing film

Methodology Applied

Scientific EffectChemical dissolution:

Data Source

PatentUS11233023B2Semiconductor device and method of manufacturing semiconductor device

Publication Date: 2022.01.25 KK TOSHIBA

AI summary

A semiconductor device of an embodiment includes: a semiconductor substrate; a first insulating layer provided on or above the semiconductor substrate; an aluminum layer provided on the first insulating layer; a second insulating layer provided on the first insulating layer, the second insulating layer covering a first region of a surface of the aluminum layer; and an aluminum oxide film provided on a second region other than the first region of the surface of the aluminum layer, the aluminum oxide film including α-alumina as a main component, and a film thickness of the aluminum oxide film being equal to or larger than 0.5 nm and equal to or smaller than 3 nm.