3D Substrate Interconnect for Uniform Power Amplifier Bondpad Feeding

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Solution Overview

Problem

Conventional power amplifiers face challenges in achieving uniform power distribution across elongated bondpads due to the use of wirebond arrays, leading to sub-optimal performance in terms of maximum output power, gain, and efficiency.

Innovation Solution

The implementation of a three-dimensional interconnect structure that eliminates wirebond arrays by using a substrate with alternating dielectric and conductive layers and conductive vias to connect power transistor die bondpads, ensuring uniform power distribution and reduced inductance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wirebond arrays are used to connect elongated bondpads to planar transmission lines, then electrical connections can be established, but uniform power distribution across the bondpad length cannot be achieved

Engineering Contradiction:
Improvepower distribution uniformityVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from a two-dimensional wirebond array connection method to a three-dimensional interconnect structure embedded within the substrate. The conductive layers and vias create vertical and lateral pathways that distribute power uniformly across the elongated bondpad length, resolving the non-uniform power distribution issue while maintaining connection functionality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent extracts and eliminates the wirebond arrays from the connection architecture. By removing the wirebond assembly steps and replacing them with integrated substrate interconnects, the solution simplifies the overall device structure while achieving superior power distribution uniformity across the bondpads.

Inventive Principle:
Principle #2Taking out (Extraction)

2Power

If wirebond arrays are used for connecting dies to transmission lines, then electrical connections are established, but inductance is increased

Engineering Contradiction:
Improveamplifier output powerVSAvoidinterconnect structure
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical wirebond assembly process with an integrated semiconductor fabrication process. The conductive layers and vias are formed through standard semiconductor manufacturing steps, eliminating the need for separate wirebond assembly and reducing overall inductance while maintaining electrical connection functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If wirebond assembly steps are used to connect elongated bondpads, then electrical connections can be made, but manufacturing complexity and time increase

Engineering Contradiction:
Improveassembly process simplicityVSAvoidwirebond assembly time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent merges the interconnect formation process with the substrate fabrication process. The conductive layers and vias are created during standard semiconductor manufacturing steps, eliminating the need for separate wirebond assembly operations. This integration reduces both manufacturing complexity and assembly time while achieving the required electrical connections.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances amplifier performance by increasing power and efficiency while facilitating miniaturization and eliminating the need for wirebond assembly steps, thus complying with higher band specifications.

Implementation Method 1

a conductive structure connected between the first and second die contacts. The conductive structure is formed from portions of the patterned conductive layers and at least two vias of the plurality of conductive vias

Methodology Applied
Scientific EffectElectrical Conduction: Conduction (electrical)

Data Source

PatentEP4343837B1Power amplifier device having dies with elongated bondpads connected through a device substrate
Publication Date: 2025.11.05 NXP USA INC
  • EP4343837B1 patent drawingFigure 1
  • EP4343837B1 patent drawingFigure 2A~2B
  • EP4343837B1 patent drawingFigure 3

AI summary

A power amplifier device includes first and second power transistor dies and a substrate. Each die includes an elongated bondpad and an integrated transistor with a terminal that is coupled to the elongated bondpad. The substrate is formed from a stack of multiple dielectric layers and multiple patterned conductive layers in an alternating arrangement, and a plurality of conductive vias electrically coupling portions of the conductive layers. The substrate includes elongated first and second die contacts exposed at a first substrate surface and connected to the first and second elongated bondpads, respectively. The substrate also includes a conductive structure connected between the first and second die contacts. The conductive structure is formed from portions of the patterned conductive layers and at least two vias of the plurality of conductive vias.