Integrated Passive Device Inductor on Encapsulant
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Solution Overview
Problem
Conventional semiconductor devices face limitations in achieving a large value inductor within a semiconductor package without using a high resistivity semiconductor substrate, which increases manufacturing costs and can interfere with the operation of the die due to eddy current losses.
Innovation Solution
A method of forming a semiconductor device that includes a semiconductor die with a low resistivity substrate, where a capacitor is formed over the die, and an encapsulant with higher resistivity than the die is deposited around it. A conductive layer is formed over the encapsulant, wound to operate as an inductor, and electrically connected to the capacitor, thereby locating the inductor away from the die to minimize eddy current losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high resistivity semiconductor substrate is used to form a large value inductor, then the inductor value is improved, but the manufacturing cost increases and eddy current losses interfere with die operation
Solution Approach 1:
The patent moves the inductor formation from the traditional substrate plane to the encapsulant surface, utilizing the third dimension (vertical space above the die) to accommodate the inductor structure. This dimensional transition allows the inductor to be formed away from the die, eliminating eddy current interference while using low-cost standard substrates.
Solution Approach 2:
The encapsulant serves as an intermediary medium that supports the inductor structure and provides electrical isolation. By forming the inductor on the encapsulant surface rather than directly on the substrate, the patent eliminates harmful eddy current interactions while maintaining inductor functionality, resolving the contradiction between performance and cost.
2Quantity of substance
If a high resistivity semiconductor substrate is used to form a large value inductor, then the inductor value is improved, but eddy current losses interfere with die operation
Solution Approach 1:
The patent extracts the inductor from the substrate environment and relocates it to the encapsulant surface. This separation removes the inductor away from the die, eliminating the harmful eddy current losses that occur when the inductor is formed on the substrate, while preserving the inductor's electrical functionality.
Solution Approach 2:
The encapsulant acts as an intermediary that provides electrical isolation between the inductor and the substrate. This intermediary layer prevents eddy current losses from affecting die operation while still allowing the inductor to function properly, resolving the harmful effects without sacrificing inductor value.
3Area of stationary object
If the inductor is formed close to the semiconductor die, then the device footprint is reduced, but eddy current losses increase and interfere with die operation
Solution Approach 1:
The patent utilizes the vertical dimension by forming the inductor on the encapsulant surface above the die rather than in the same plane. This dimensional repositioning allows the inductor to be physically close to the die in terms of footprint while maintaining sufficient electrical isolation to prevent eddy current losses, effectively resolving the contradiction between compactness and performance.
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 allows for the creation of a large value inductor without the need for a high resistivity substrate, reducing manufacturing costs and preventing interference from eddy current losses, while maintaining the operational integrity of the semiconductor device.
Implementation Method 1
The encapsulant has a higher resistivity than the resistivity of the semiconductor die
Implementation Method 2
forming a second conductive layer over the first insulating layer. The second conductive layer has a portion formed over the encapsulant a predetermined distance away from a footprint of the semiconductor die and wound to operate as an inductor
Implementation Method 3
forming a first capacitor over the semiconductor die. The first capacitor is electrically connected to the semiconductor die
Data Source
AI summary
An IPD semiconductor device has a capacitor formed over and electrically connected to a semiconductor die. An encapsulant is deposited over the capacitor and around the semiconductor die. A first interconnect structure is formed over a first surface of the encapsulant by forming a first conductive layer, forming a first insulating layer over the first conductive layer, and forming a second conductive layer over the first insulating layer. The second conductive layer has a portion formed over the encapsulant at least 50 micrometer away from a footprint of the semiconductor die and wound to operate as an inductor. The portion of the second conductive layer is electrically connected to the capacitor by the first conductive layer. A second interconnect structure is formed over a second surface of the encapsulant. A conductive pillar is formed within the encapsulant between the first and second interconnect structures.