IC Packaging Film Structure for Precision Component Stress Isolation

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Solution Overview

Problem

Integrated circuit (IC) packages with precision components are vulnerable to mechanical stresses from molding materials, leading to performance degradation due to thermal expansion/contraction and physical forces, which existing fabrication processes fail to adequately mitigate.

Innovation Solution

A fabrication process involving a photo-patternable polymer film patterned over precision components on the semiconductor die, coupled with a substrate and covered by non-adhesive molding material, creating an air gap that isolates mechanical stresses and reduces form-factor while being less costly and complex compared to traditional methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If molding material is provided to fill gaps in the IC package, then the package structure is completed and gaps are filled, but mechanical stresses are transferred to precision components resulting in performance degradation

Engineering Contradiction:

Improvepackage structure completionVSAvoidprecision component performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A stress relief layer is introduced as an intermediary between the molding material and the precision components. This layer acts as a mediator that absorbs and dissipates mechanical stresses from the molding material, preventing stress transfer to the precision components while allowing the molding material to remain in place for structural completion.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The stress relief layer is applied beforehand to the precision components before the molding material is introduced. This pre-positioned protective layer cushions the components against upcoming mechanical stresses during the molding process, preventing performance degradation before it occurs.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If traditional stress protection methods are used, then precision components are protected from mechanical stresses, but the device complexity and fabrication cost increase

Engineering Contradiction:

Improveprecision component protectionVSAvoidfabrication process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The stress relief layer is implemented as a thin film structure that provides effective stress protection without adding significant device complexity. This thin film approach maintains fabrication simplicity while delivering the necessary mechanical stress isolation to protect precision components.

Inventive Principle:

Principle #30Flexible shells and thin films

3Volume of moving object

If precision components are placed close to the first surface for compact design, then the form-factor is reduced, but the components are more exposed to mechanical stresses from molding material

Engineering Contradiction:

ImproveIC package form-factorVSAvoidmechanical stress exposure

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The stress relief layer is applied beforehand to the precision components that are positioned close to the first surface. This pre-positioned protective layer cushions the components against mechanical stresses from the molding material, enabling compact design while maintaining component protection.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The stress relief layer serves as an intermediary between the molding material and the precision components positioned near the first surface. It absorbs mechanical stresses that would otherwise directly impact the exposed components, allowing compact packaging without sacrificing component reliability.

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

Effectively protects precision components from mechanical stresses, resulting in improved performance and a smaller form-factor IC package with reduced fabrication costs and complexity.

Implementation Method 1

a photo-patternable polymer film patterned over the precision components on the semiconductor die

Methodology Applied

Scientific EffectPhotolithography: Photopolymerisation

Implementation Method 2

molding material deposited over the semiconductor die to cover at least the first surface of the semiconductor die

Methodology Applied

Scientific EffectMolding material deposition: Deposition (physical)

Data Source

PatentUS20230274993A1Fabrication process for protecting circuit components

Publication Date: 2023.08.31 TEXAS INSTRUMENTS INC

AI summary

One example includes a method for fabricating an integrated circuit (IC) device. The method includes fabricating a semiconductor die comprising an IC. The method also includes patterning a film over a portion of the first surface of the semiconductor die. The method also includes attaching a second surface of the semiconductor die opposite the first surface to a substrate. The method further includes depositing molding material over the semiconductor die to cover at least the first surface of the semiconductor die.