Embedded Wiring Gutter for Semiconductor Reliability

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Solution Overview

Problem

The wire bonding method for semiconductor devices faces issues with wire breakage and damage due to high external forces during resin sealing, leading to reliability concerns and high costs due to the use of expensive gold wires, while also limiting wiring density.

Innovation Solution

A method involving a resin coating, laser machining to form a wiring gutter, catalyst deposition, and electroless plating to create a wiring structure that is embedded in the gutter, enhancing adhesive strength and reducing the risk of wire damage during resin sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wire bonding method is used to connect semiconductor chip to insulating base material, then electrical connection is achieved, but wire breakage occurs due to high external forces during resin sealing

Engineering Contradiction:

Improvewire connection reliabilityVSAvoidwire strength during sealing

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent introduces a resin coating layer as an intermediary between the wire and the sealing resin. This coating layer has high adhesion to both the wire and the sealing resin, acting as a buffer that distributes and reduces the external forces during sealing, thereby preventing wire breakage while maintaining connection reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies a resin coating layer to the wire surface before the sealing process. This preliminary coating provides pre-protection to the wire, ensuring it is ready to withstand the high external forces during sealing without breaking, thus improving reliability

Inventive Principle:

Principle #10Preliminary action

2Strength

If wire diameter is increased to prevent breakage, then wire strength is improved, but manufacturing cost increases due to use of expensive gold

Engineering Contradiction:

Improvewire strengthVSAvoidamount of expensive gold wire

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The resin coating layer serves as a protective intermediary that allows the use of thinner, less expensive wires while still preventing breakage during sealing. The coating bears part of the mechanical stress, enabling cost reduction by reducing or eliminating the need for thick gold wires

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If wire bonding method is used, then electrical connection is achieved, but wiring density is limited due to wire sweep amount

Engineering Contradiction:

Improveconnection reliabilityVSAvoidwiring density

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the mechanical wire bonding process with a chemical/electrochemical approach using electroless plating. This substitution allows wiring to be formed in locations that would be inaccessible to wire bonding due to sweep limitations, thereby increasing wiring density while maintaining connection reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Stability of the object's composition

If seal material with large amounts of inorganic filling material is used for sealing, then insulation and dimensional stability are improved, but fluidity deteriorates requiring extremely high molding pressure

Engineering Contradiction:

Improvedimensional stabilityVSAvoidmolding process ease

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The resin coating layer on the wire acts as an intermediary that protects the wire from the high molding pressure required when using seal material with inorganic fillers. This coating distributes the pressure and prevents wire damage, enabling the use of high-stability seal materials without compromising wire integrity

Inventive Principle:

Principle #24Intermediary (Mediator)

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 adhesive strength of the wiring, reduces the risk of wire breakage and disconnection, and allows for higher wiring density without the need for expensive gold, enhancing the reliability and efficiency of semiconductor device manufacturing.

Implementation Method 1

a wiring gutter forming step of forming, by laser beam machining, a wiring gutter having a depth that is equal to or greater than a thickness of the resin coating

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

a plating processing step of forming, after the resin coating is removed, an electroless plating coating only at a site where the plating catalyst or a plating catalyst formed from the plating catalyst precursor remains

Methodology Applied

Scientific EffectElectroless plating: Catalysis

Data Source

PatentUS9082438B2Three-dimensional structure for wiring formation

Publication Date: 2015.07.14 PANASONIC HOLDINGS CORP

AI summary

One aspect of the present invention is a three-dimensional structure that has a concave-convex form including a gutter for wiring having at least partially a width of 20 μm or less, wherein at least a part of a wiring conductor is embedded in the gutter for wiring, and a wiring that extends in such a manner as to creep along the concave-convex form is provided.