Aluminum Alloy Patterning for Convex Defect Conversion in MOS Wafers

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Solution Overview

Problem

Conventional semiconductor device manufacturing methods face issues with convex-shaped defects in aluminum alloy films, which lead to poor electrical characteristics and detection challenges due to integration of foreign matter, resulting in concave-shaped defects and application voids during subsequent processes.

Innovation Solution

A method involving the formation of a thinner resist film to partially expose convex-shaped defects on the aluminum alloy film, allowing for conversion of these defects into concave-shaped defects, enhancing detection sensitivity and preventing cracking during wafer handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If foreign matter is integrated into the aluminum alloy film during deposition, then the film formation is simplified, but convex-shaped defects are created that lead to poor electrical characteristics and detection challenges

Engineering Contradiction:

Improvefilm formation processVSAvoidelectrical characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies a thinner resist film in advance before aluminum alloy film deposition, so that when foreign matter is integrated during deposition, it creates convex-shaped defects that are already positioned to be partially exposed. This preliminary action sets up the defect structure that will later be converted to concave-shaped defects, solving the reliability issue while maintaining manufacturing simplicity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of foreign matter integration (which creates convex-shaped defects) into a beneficial outcome. By using a thinner resist film, the convex-shaped defects are partially exposed, and subsequent processing transforms them into concave-shaped defects that improve electrical characteristics and detection, thus turning the harmful integration of foreign matter into a useful defect conversion mechanism

Inventive Principle:

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

2Strength

If a thick resist film is used to cover convex-shaped defects, then the aluminum alloy film is protected, but detection sensitivity decreases and application voids occur

Engineering Contradiction:

Improveprotection of aluminum alloy filmVSAvoiddetection sensitivity

Core Design Contradiction:

StrengthVSMeasurement precision

Solution Approach 1:

The patent uses a thinner resist film that provides localized protection rather than complete coverage. The resist film thickness is specifically controlled to be sufficient to protect the aluminum alloy film in defect-free areas while being thin enough to allow partial exposure of convex-shaped defects in areas where foreign matter is integrated, thus achieving both protection and detection

Inventive Principle:

Principle #3Local quality

3Measurement precision

If the resist film thickness is reduced to partially expose convex-shaped defects, then detection sensitivity improves, but the aluminum alloy film becomes more vulnerable

Engineering Contradiction:

Improvedetection sensitivityVSAvoidprotection of aluminum alloy film

Core Design Contradiction:

Measurement precisionVSStrength

Solution Approach 1:

The patent changes the key parameter of resist film thickness to an optimal value that balances two conflicting requirements. By reducing the thickness from conventional levels to a specific thinner range, the resist film allows partial exposure of convex-shaped defects for improved detection while still maintaining sufficient protection of the aluminum alloy film during processing

Inventive Principle:

Principle #35Parameter changes

4Productivity

If convex-shaped defects are present on the aluminum alloy film, then the manufacturing process continues, but cracking occurs during wafer handling and application voids are created

Engineering Contradiction:

Improvemanufacturing continuityVSAvoidcracking and application voids

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts convex-shaped defects (which cause cracking and application voids) into concave-shaped defects through a controlled process. The thinner resist film allows partial exposure of convex defects, and subsequent processing steps transform them into concave defects that are benign or even beneficial, thus eliminating the harmful effects while maintaining manufacturing continuity

Inventive Principle:

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

Solution Approach 2:

The patent applies the thinner resist film and processes the aluminum alloy film in advance to convert convex-shaped defects into concave-shaped defects before subsequent manufacturing steps. This preliminary conversion prevents cracking during wafer handling and eliminates application voids in later processes, ensuring manufacturing continuity without harmful effects

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240339332A1Method of manufacturing semiconductor device

Publication Date: 2024.10.10 FUJI ELECTRIC CO LTD

AI summary

A method of manufacturing a semiconductor device includes forming a surface structure having a MOS structure in a semiconductor substrate; forming an interlayer insulating film partially covering the surface structure; forming an aluminum alloy film in contact with the surface structure and covering an entire area where the surface structure, including the interlayer insulating film, is formed; forming a resist film covering the surface of the aluminum alloy film so as to have a thickness partially exposing a convex-shaped defect of the aluminum alloy film; patterning the aluminum alloy film using the resist film as a mask; and removing the resist film.