Transformer-Based Chip-to-Package Interface for Signal Loss Reduction
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Solution Overview
Problem
Current semiconductor packages face challenges in minimizing signal loss during the transition from millimeter-wave integrated circuit chips to printed circuit boards, especially due to single-ended signal interfaces, which are complex to route and prone to common mode noise, while also needing protection from mechanical and environmental stress without increasing packaging costs.
Innovation Solution
A millimeter-wave embedded wafer level semiconductor package with a transformer structure, featuring a first coil within the semiconductor chip and a second coil outside the chip, providing a differential signal interface at the chip level and a single-ended interface at the package level, which reduces signal loss and simplifies routing on the printed circuit board, while also enhancing robustness against mechanical and environmental stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single-ended signal interface is used at the package level, then routing on the printed circuit board is simplified, but signal loss increases and common mode noise susceptibility increases
Solution Approach 1:
The signal interface is segmented into two distinct levels: a differential interface at the chip level and a single-ended interface at the package level. This segmentation allows each interface to be optimized independently - the differential interface minimizes signal loss and noise susceptibility at the chip, while the single-ended interface simplifies PCB routing externally.
Solution Approach 2:
A transformer structure serves as an intermediary element between the chip and the package. The transformer converts between differential and single-ended signals, enabling the chip to operate with a differential interface (reducing signal loss) while the package interface remains single-ended (simplifying routing).
2Loss of energy
If a differential signal interface is used at the chip level, then signal loss is reduced and common mode immunity is improved, but routing complexity increases
Solution Approach 1:
The signal interface is segmented into two distinct levels: a differential interface at the chip level and a single-ended interface at the package level. This segmentation allows each interface to be optimized independently - the differential interface minimizes signal loss and noise susceptibility at the chip, while the single-ended interface simplifies PCB routing externally.
Solution Approach 2:
A transformer structure serves as an intermediary element between the chip and the package. The transformer converts between differential and single-ended signals, enabling the chip to operate with a differential interface (reducing signal loss) while the package interface remains single-ended (simplifying routing).
3Reliability
If on-chip signal pads are used, then direct electrical connection is achieved, but electro-static discharge protection is reduced and signal loss increases
Solution Approach 1:
The signal pads are extracted from the chip substrate and relocated to the package substrate. This extraction removes the pads from the chip, eliminating the direct electrical connection path that causes signal loss and reduces ESD protection. The transformer coils replace the traditional pad structure.
Solution Approach 2:
The traditional mechanical/electrical direct connection through metal pads is replaced with an electromagnetic coupling mechanism. The transformer coils create an inductive coupling that transfers signals without direct electrical contact, reducing signal loss and improving ESD protection.
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 minimizes signal loss through the package, maintains high common-mode immunity, and simplifies the printed circuit board routing, while eliminating the need for on-chip signal pads and providing electro-static discharge protection, thus enhancing the reliability and performance of millimeter-wave semiconductor chips.
Implementation Method 1
The first coil is magnetically coupled to the second coil
Data Source
AI summary
In accordance with an embodiment of the present invention, a semiconductor package includes a semiconductor chip disposed within an encapsulant, and a first coil disposed in the semiconductor chip. A dielectric layer is disposed above the encapsulant and the semiconductor chip. A second coil is disposed above the dielectric layer. The first coil is magnetically coupled to the second coil.