Silicone Surface Modification for Semiconductor Mold Adhesion

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Solution Overview

Problem

Semiconductor devices face challenges in achieving effective protection from external influences such as humidity and dust, particularly in demanding applications like automotive, where existing protective measures like mold compounds based on epoxy resin may not provide sufficient durability and longevity.

Innovation Solution

A method involving the formation of a silicone layer on a semiconductor die, followed by plasma treatment and the deposition of a surfactant with an inorganic skeleton terminated by organic compounds, which enhances the adhesion of a mold to the silicone layer, thereby improving protection and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mold compound based on epoxy resin is used to protect the semiconductor device, then protection from external influences is provided, but durability and longevity are insufficient

Engineering Contradiction:

Improveprotection from external influencesVSAvoidlife cycle and durability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent uses a composite protective structure consisting of a silicone layer combined with a mold compound. The silicone layer provides flexibility and environmental protection, while the mold compound provides structural protection. This composite approach resolves the contradiction by combining materials with complementary properties to achieve both adequate protection and improved durability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the surface properties of the silicone layer through plasma treatment and surfactant application. These parameter changes in surface energy and wettability enable better adhesion of the mold compound to the silicone layer, thereby improving the overall durability and longevity of the protective structure without compromising its protective function.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a silicone layer is formed on the semiconductor die, then improved protection is achieved, but adhesion to the mold compound is insufficient

Engineering Contradiction:

Improveprotection from external influencesVSAvoidadhesion between silicone layer and mold

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies plasma treatment to modify the surface energy and chemical composition of the silicone layer, and then applies surfactants to further adjust surface properties. These parameter changes in surface chemistry create optimal conditions for adhesion between the silicone layer and the mold compound, resolving the contradiction between providing protective functionality and ensuring strong bonding.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The surfactant acts as an intermediary substance between the silicone layer and the mold compound. It facilitates adhesion by creating compatible surface properties that enable strong bonding between the two materials, thus resolving the adhesion issue while maintaining the protective function of the silicone layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If the silicone surface is plasma treated, then adhesion properties are improved, but the surface may become hydrophobic over time

Engineering Contradiction:

Improveadhesion forcesVSAvoidsurface hydrophilicity

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent performs plasma treatment and surfactant application as preliminary actions before forming the mold compound. This preliminary modification of the silicone surface ensures optimal adhesion properties are established before the mold compound is applied, and the surfactant creates a stable surface that resists hydrophobic recovery over time.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The surfactant serves as a stable intermediary layer that maintains the surface properties needed for adhesion. It prevents the silicone surface from becoming hydrophobic over time by creating a stable surface chemistry that retains its adhesion properties, thus resolving the contradiction between initial adhesion improvement and long-term surface stability.

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

The method results in stronger adhesion forces between the silicone layer and the mold, providing enhanced protection against external influences and extending the life cycle of semiconductor devices.

Implementation Method 1

plasma treating a silicone surface of the silicone layer

Methodology Applied

Scientific EffectPlasma treatment: Plasma

Implementation Method 2

depositing a surfactant on the plasma-treated silicone surface

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS10453806B2Methods for forming semiconductor devices and semiconductor device

Publication Date: 2019.10.22 INFINEON TECH AUSTRIA AG

AI summary

A method for forming a semiconductor device and semiconductor device is disclosed. In one example, the method includes forming a silicone layer on a semiconductor die. The method further includes plasma treating a silicone surface of the silicone layer. A surfactant is deposited on the plasma-treated silicone surface of the silicone layer to obtain a silicone surface at least partly covered by surfactant. A mold is formed on the silicone surface at least partly covered by surfactant. The surfactant includes surfactant molecules comprising an inorganic skeleton terminated by organic compounds.