Laser Oxide Film Solder Resist for Semiconductor Devices

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Solution Overview

Problem

Conventional solder resist films with resin compositions used in semiconductor manufacturing face issues such as exfoliation during thermal processes, chemical treatments, and high manufacturing costs due to the need for multiple masks and lengthy drying and hardening steps, as well as difficulties in forming fine patterns and maintaining mask integrity.

Innovation Solution

A method involving the formation of an oxide film on the peripheral regions of components using pulsed laser light to prevent solder from flowing outside the intended bonding area, which is more durable and cost-effective, allowing for reduced steps and improved pattern flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solder resist film with resin composition is used to prevent solder overflow, then solder adhesion control is improved, but the film exfoliates during thermal and chemical treatments

Engineering Contradiction:

Improvesolder adhesion controlVSAvoidfilm integrity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention changes the material parameter from organic resin to inorganic oxide, fundamentally altering the chemical composition to achieve both solder adhesion control and thermal/chemical stability. The oxide film maintains its integrity during treatments while preventing solder overflow effectively.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The oxide film serves as a temporary protective layer during soldering that can be removed or degraded after serving its purpose, replacing the durable but problematic resin film with a controlled, short-lived protective barrier.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If multiple masks and drying steps are used to form solder resist film, then pattern precision is improved, but manufacturing complexity and time increase

Engineering Contradiction:

Improvepattern precisionVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the mask and drying steps from the manufacturing process, using direct oxide film formation that inherently provides the required pattern precision without additional equipment or process steps.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical mask-based patterning system is replaced with a direct oxide formation method, substituting complex mechanical processes with a simpler, more integrated approach that achieves the same patterning function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If resin-based solder resist is used, then solder overflow prevention is achieved, but manufacturing cost increases due to multiple process steps

Engineering Contradiction:

Improvesolder overflow preventionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention merges the oxide formation step with the base material preparation process, creating the protective film as an integrated part of the substrate rather than as a separate applied layer, thereby reducing overall manufacturing cost.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The oxide film serves multiple functions simultaneously: it prevents solder overflow, provides thermal stability, offers chemical resistance, and can be formed as part of the base material preparation, replacing multiple separate functions that would otherwise require different materials and processes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 oxide film effectively prevents solder overflow, remains intact through thermal and chemical treatments, and reduces manufacturing complexity and costs by eliminating the need for multiple masks and lengthy drying processes, while allowing for flexible pattern adjustments.

Implementation Method 1

shooting a laser light to at least one part of an outer peripheral portion surrounding a soldering-target region of the first member thereby to form an oxide film

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

form an oxide film

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS8273644B2Soldering method and method of manufacturing semiconductor device including soldering method

Publication Date: 2012.09.25 FUJI ELECTRIC CO LTD

AI summary

A soldering method of soldering first and second members includes shooting a laser light to at least one part of an outer peripheral portion surrounding a soldering-target region of the first member thereby to form an oxide film, and bonding the second member with the soldering-target region through a solder. According to the method, the solder resist is never exfoliated even after cleaning with chemicals for removing flux residues contained in solder.