Semiconductor Package Layout for Medium-Frequency Loss Reduction
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Solution Overview
Problem
Semiconductor packages experience increased resistance and power losses due to skin and proximity effects at medium frequency ranges (300 kHz to 3 MHz), which existing technologies fail to adequately mitigate.
Innovation Solution
Incorporation of a metallic member within the semiconductor package that is inductively coupled but electrically resistively insulated from other metallic components, inducing eddy currents to redistribute current flow and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional semiconductor packages are used at medium frequencies, then the package structure is simple and manufacturing is easy, but resistance increases and power losses occur due to skin and proximity effects
Solution Approach 1:
A metallic member is introduced as an intermediary element between the connector and the die pad. This metallic member is electrically isolated from both components but magnetically coupled to them, serving as a mediator to counteract the harmful skin and proximity effects without requiring direct electrical connection, thus reducing power losses while maintaining a relatively simple package structure
Solution Approach 2:
The invention changes the electrical parameter configuration by introducing a metallic member with specific geometric parameters (surface area, position, thickness) that can be optimized for different frequency ranges. By adjusting these parameters, the package can be tuned to operate efficiently in the medium frequency range (300 kHz to 3 MHz), transforming the package from a simple DC/low-frequency structure to one optimized for medium frequencies
2Reliability
If a metallic member is added to reduce resistance, then power losses are reduced, but manufacturing complexity increases
Solution Approach 1:
The metallic member is merged with the mold compound in a single molding process, eliminating the need for separate assembly steps. The mold compound serves dual functions as both the encapsulating material and the mounting medium for the metallic member, simplifying the manufacturing process while ensuring reliable positioning and electrical isolation
Solution Approach 2:
The metallic member is positioned and fixed automatically during the mold compound injection process, utilizing the flow and pressure of the mold compound to achieve proper placement. This self-positioning capability reduces the need for complex alignment and fixation mechanisms, thereby simplifying manufacturing while ensuring consistent positioning for reliable performance
3Loss of energy
If the metallic member is electrically connected to the connector, then current flow is improved, but skin and proximity effects worsen due to additional eddy currents
Solution Approach 1:
The electrical path is segmented into isolated sections by introducing the metallic member as a separate, electrically isolated component. Instead of a continuous conductive path that would allow eddy currents to propagate, the magnetic coupling creates discrete, non-interconnected electrical zones that suppress harmful eddy current formation while maintaining the beneficial effect on current distribution
Solution Approach 2:
The direct electrical (mechanical) connection between the metallic member and the connector is replaced by magnetic coupling. This substitution eliminates the formation of closed electrical loops that would generate eddy currents, while still achieving the desired effect of counteracting skin and proximity effects through magnetic field interaction
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 solution effectively reduces package resistance by up to 40% and power losses, making the semiconductor package suitable for medium frequency applications.
Implementation Method 1
a metallic member which is inductively coupled to the connector and which is electrically resistively insulated from the connector
Implementation Method 2
eddy currents are induced in the metallic member by AC source currents flowing in the connector
Implementation Method 3
the skin effect in the connector leads to concentration of electric current near the connector surface and a reduction of the effective cross section area
Implementation Method 4
inductive coupling between currents in the connector and other parts of the package such as the leadframe and the metallization of the semiconductor die, causes proximity effects resulting concentration of current on the inner side of the connector
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 2C~2E
AI summary
In an embodiment, a semiconductor package (10, 10', 10", 10‴, 100) comprises a semiconductor die (11) having a first surface (24), a second surface (25) opposing the first surface (24), a first contact pad (26) on the first surface (24) and a second contact pad (27) on the second surface (26), a die pad (13) and at least one lead (14) spaced apart from the die pad (13), wherein the first contact pad (26) of the semiconductor die (11) is mounted on the die pad (13) and the second contact pad (27) is electrically connected to the at least one lead (14) by a connector (15), a mold compound (16) covering the semiconductor die (11), the connector (15) and an upper surface (28) of the die pad (13) and of the at least one lead (14) and a metallic member (17) which is inductively coupled to the connector (15) and which is electrically resistively insulated from the connector (15). The metallic member (17) comprises a web portion (34) arranged above the second surface (26) of the semiconductor die (11) and at least one peripheral rim portion (35) that extends from the web portion (34) in a direction towards the first surface (24) of the semiconductor die (11).