Die Attachment Beads and Barrier Films for Semiconductor Shorting

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Solution Overview

Problem

The semiconductor industry faces issues with uncontrolled movement of die attachment materials, leading to electrical shorting in semiconductor packages, which current methods fail to adequately address.

Innovation Solution

Incorporating a non-conductive barrier material on a substrate, such as a lead frame, to restrict the movement of die attachment materials, preventing electrical shorting by applying it between regions with and without die attachment material, and using suitable materials like gels, films, or adhesives that can be cured for stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If die attachment material is used to mount the semiconductor die, then the die can be securely attached to the substrate, but the die attachment material exhibits uncontrolled movement that causes electrical shorting

Engineering Contradiction:

Improveattachment strengthVSAvoidelectrical shorting risk

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The die attachment material is segmented into discrete spherical beads rather than being applied as a continuous layer. This segmentation prevents uncontrolled lateral flow and movement of the material during assembly and reflow processes, while still providing sufficient attachment strength at the die-to-substrate interface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A release film with release coating is applied over the die attachment material during assembly, then removed after bonding. This temporary flexible film constrains the die attachment material during the critical assembly phase, preventing uncontrolled movement, and is subsequently removed to allow proper bonding without causing electrical shorts.

Inventive Principle:

Principle #30Flexible shells and thin films

2Ease of manufacture

If conventional die attachment methods are used, then the die can be mounted on the substrate, but uncontrolled movement of the attachment material occurs during assembly and reflow

Engineering Contradiction:

Improvedie mounting capabilityVSAvoidattachment material position stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The die attachment material is pre-applied in controlled spherical bead form before die placement, and a release film is temporarily applied to constrain the material. This preliminary constraint prevents uncontrolled movement during assembly and reflow, maintaining position stability throughout the manufacturing process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The die attachment material is changed from a conventional paste or epoxy form to discrete spherical beads with controlled size and spacing. This parameter change in material form and geometry provides inherent resistance to lateral flow while maintaining bonding capability, solving the stability issue during manufacturing.

Inventive Principle:

Principle #35Parameter changes

3Strength

If more die attachment material is used to ensure secure attachment, then the attachment strength increases, but the risk of electrical shorting increases due to material movement

Engineering Contradiction:

Improveattachment strengthVSAvoidelectrical shorting hazard

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

Instead of using large amounts of continuous die attachment material, the material is segmented into multiple small spherical beads distributed at the die-to-substrate interface. This segmentation provides sufficient total attachment strength through distributed bonding points while preventing lateral flow and electrical shorting between adjacent beads.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11557530B2Semiconductor devices and methods of making the same

Publication Date: 2023.01.17 SEMICON COMPONENTS IND LLC

AI summary

In one embodiment, methods for making semiconductor devices are disclosed.