LTCC Package Reducing Inductance via Flush Die Mounting
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Solution Overview
Problem
Current methods for forming millimeter wave integrated LTCC packages face challenges in reducing inductance and parasitic capacitance, particularly at high frequencies, which hinders efficient energy transfer between the die and the PCB without introducing parasitic elements.
Innovation Solution
The approach involves using either wire bonding or flip chip technology to attach the die to the package, with the latter utilizing copper pillars or bumps for direct attachment, and incorporating coaxial transmission lines within the LTCC structure to minimize inductance and parasitic capacitance, enabling efficient energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If wire bonding or flip chip technology is used to attach the die to the package, then the die can be securely mounted, but inductance and parasitic capacitance are introduced that hinder efficient energy transfer at high frequencies
Solution Approach 1:
The patent extracts and eliminates the traditional wire bonding and flip chip attachment methods that introduce harmful inductance and parasitic capacitance. Instead, the die is directly mounted onto the LTCC package substrate using conductive paste, completely removing the intermediate bonding structures that generate these harmful electrical characteristics.
Solution Approach 2:
The patent introduces an intermediary conductive paste layer between the die and LTCC substrate that provides both mechanical attachment and electrical connection without introducing significant inductance or parasitic capacitance. This intermediary material enables direct coupling while maintaining signal integrity at millimeter wave frequencies.
2Reliability
If traditional packaging methods are used, then the die is protected and mounted, but energy transfer efficiency is reduced due to parasitic elements at millimeter wave frequencies
Solution Approach 1:
The patent merges the die mounting function with the LTCC package substrate by directly attaching the die to the substrate using conductive paste. This integration eliminates separate bonding layers and intermediate structures, creating a unified structure that reduces parasitic elements and improves energy transfer efficiency while maintaining die protection.
Solution Approach 2:
The patent changes the electrical parameters of the attachment interface by using conductive paste with optimized electrical characteristics instead of traditional wire bonds or flip chip structures. This parameter change reduces inductance and parasitic capacitance values, enabling efficient energy transfer at millimeter wave frequencies while maintaining mechanical reliability.
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 solution reduces inductance and parasitic capacitance, allowing for effective energy transfer at high frequencies, enhancing the integration and performance of millimeter wave components within the LTCC package while maintaining a low-cost and flexible design.
Implementation Method 1
incorporating coaxial transmission lines within the LTCC structure to minimize inductance and parasitic capacitance, enabling efficient energy transfer
Data Source
AI summary
LTCC structure extends between top and bottom surfaces, with at least one cavity being formed within the structure and extending from the top surface inwardly in the direction of the bottom surface. A die is disposed within the cavity a top surface of the die is positioned flush with the top surface of the package, resulted in the shortest length of the wire box connecting the die with the LTCC structure and ultimately reducing the inductance.