On-Chip Inductor Shield Layer for Reduced Substrate Coupling
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Solution Overview
Problem
The integration of on-chip inductors in semiconductor devices leads to electrical coupling with the substrate, causing a coupling current that reduces the quality factor and affects performance, particularly in radio frequency integrated circuits.
Innovation Solution
A shield layer is formed between the substrate and the inductor to shield electrical coupling, which can be grounded or connected to the substrate through conductive holes, and the substrate's doping density or thickness is adjusted to reduce coupling current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an on-chip inductor is formed on the substrate to achieve integration, then device integration and ease of manufacture are improved, but electrical coupling with the substrate causes coupling current that reduces the quality factor and increases energy loss
Solution Approach 1:
A shield layer is introduced as an intermediary component between the substrate and the inductor. This shield layer acts as a mediator that blocks the electrical coupling and coupling current paths while maintaining the integrated structure. The shield layer is connected to ground through conductive vias, providing a preferred path for electromagnetic field termination and preventing energy loss through substrate coupling.
Solution Approach 2:
The structure is segmented into distinct functional layers: the substrate, the shield layer, and the inductor layer. This segmentation separates the inductor from direct contact with the substrate, breaking the coupling current path while maintaining manufacturing integration through sequential layer formation in a multi-layer semiconductor process.
2Ease of manufacture
If the inductor is integrated on the chip to reduce cost and improve integration, then manufacturing cost and integration are improved, but the quality factor of the inductor is reduced due to substrate coupling
Solution Approach 1:
The shield layer serves as an intermediary that preserves the low-cost integrated manufacturing approach while improving reliability. It is formed using standard semiconductor fabrication processes (sputtering, CVD, or electroplating) and integrated into existing multi-layer metal structures, maintaining cost-effectiveness while significantly improving the quality factor by reducing substrate coupling effects.
Solution Approach 2:
The solution moves from a two-dimensional planar inductor directly on the substrate to a three-dimensional layered structure with the shield layer positioned vertically between the substrate and inductor. This dimensional change creates electromagnetic isolation while maintaining the compact integrated form factor suitable for cost-effective manufacturing.
3Reliability
If a shield layer is added to reduce coupling current, then quality factor is improved, but device complexity increases
Solution Approach 1:
The shield layer is designed to serve multiple functions: it acts as an electromagnetic shield to improve quality factor, provides a ground reference plane for the inductor, and can be integrated with existing ground structures in the semiconductor device. This multi-functionality reduces the need for additional separate components and minimizes overall device complexity despite adding the shield layer.
Solution Approach 2:
The shield layer is merged with the existing multi-layer metal structure of the semiconductor device. The conductive vias connecting the shield layer to ground are integrated with the existing via structure, and the shield layer material is deposited using the same sputtering, CVD, or electroplating processes used for other metal layers, thereby reducing process complexity.
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 shield layer reduces the coupling current, improving the quality factor of the inductor and enhancing the performance of the semiconductor device by minimizing energy loss.
Implementation Method 1
a shield layer is formed between the substrate and the inductor, and the shield layer is used to shield an electrical coupling between the substrate and the inductor
Data Source
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AI summary
A semiconductor device and a manufacturing method therefor are provided. The semiconductor device includes a substrate (100) and an inductor (200), where a shield layer (300) may be formed between the substrate (100) and the inductor (200), and the shield layer (300) is used to shield an electrical coupling between the substrate (100) and the inductor (200). In this way, a coupling current in the substrate (100) can be reduced, an energy loss in the inductor (200) is reduced, a quality factor of the inductor (200) is improved, and performance of the semiconductor device is improved.