Laser-Formed Conductive Tracks in Molded Semiconductor Encapsulant

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Solution Overview

Problem

Conventional packaging solutions for semiconductor devices with densely arranged bond pads are ineffective and performance-limiting for providing unique electrical connections, as they struggle to meet the interconnect requirements of modern semiconductor devices.

Innovation Solution

A packaged semiconductor device with a laser-activatable mold compound encapsulant body that forms conductive tracks using a laser patterning technique, combined with vertical interconnect structures like wire stud bumps or metal pillars, to create high-density electrical connections between semiconductor dies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional packaging interconnect structures (bond wires, clips, ribbons) are used, then the packaging process is simple and cost-effective, but they are ineffective and performance-limiting for densely arranged bond pads

Engineering Contradiction:

Improveinterconnect effectivenessVSAvoidpackaging structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical interconnect structures (bond wires, clips, ribbons) with a laser-formed conductive track system embedded in the encapsulant. This substitution enables high-density interconnects for densely arranged bond pads while maintaining packaging simplicity through direct laser writing on the mold compound surface.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state and properties of the mold compound by using laser irradiation to create conductive pathways. The laser energy transforms the insulating mold compound into a conductive track structure, enabling new interconnect capabilities without changing the overall packaging architecture.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the size of semiconductor device is reduced and functional capability is increased, then the device density and functionality improve, but the bond pads become densely arranged creating packaging challenges

Engineering Contradiction:

Improvedevice functionalityVSAvoidbond pad arrangement complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical bonding methods with direct laser-formed conductive tracks that can be precisely positioned on densely arranged bond pads. This enables effective interconnection of high-density bond pad arrangements that would be impossible with traditional mechanical interconnect structures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If conventional packaging solutions are used for densely arranged bond pads, then the manufacturing process remains simple, but the electrical connection performance becomes limiting

Engineering Contradiction:

Improveelectrical connection performanceVSAvoidpackaging manufacturing simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces complex multi-step mechanical interconnect fabrication with a simplified laser direct-writing process. The laser forms conductive tracks directly on the mold compound surface in a single step, achieving high-performance electrical connections while maintaining manufacturing simplicity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The mold compound serves dual functions: as the encapsulant material and as the substrate for forming conductive tracks. The laser irradiation process directly modifies the mold compound to create conductive pathways, eliminating the need for separate interconnect fabrication steps.

Inventive Principle:

Principle #25Self-service

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 solution enables high-density interconnect capabilities, allowing for efficient electrical connections between semiconductor dies, supporting both low and high current/voltage signals, and enhancing the packaging of modern semiconductor devices without the limitations of conventional methods.

Implementation Method 1

The conductive tracks are formed by a laser patterning technique in an upper surface of the encapsulant body

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS11569196B2Chip to chip interconnect in encapsulant of molded semiconductor package

Publication Date: 2023.01.31 INFINEON TECHNOLOGIES AG

AI summary

A packaged semiconductor includes an electrically insulating encapsulant body having an upper surface, a first semiconductor die encapsulated within the encapsulant body, the first semiconductor die having a main surface with a first conductive pad that faces the upper surface of the encapsulant body, a second semiconductor die encapsulated within the encapsulant body and disposed laterally side by side with the first semiconductor die, the second semiconductor die having a main surface with a second conductive pad that faces the upper surface of the encapsulant body, and a first conductive track that is formed in the upper surface of the encapsulant body and electrically connects the first conductive pad to the second conductive pad. The encapsulant body includes a laser activatable mold compound.