Semiconductor Wiring Layout for Low-Inductance Heat Dissipation
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Solution Overview
Problem
Existing semiconductor devices with double-sided heat dissipation structures face challenges in reducing thermal resistance while minimizing inductance, as thicker conductive spacers increase magnetic flux cancellation effects but also enhance thermal resistance, and cutouts to avoid bonding wire contact can inhibit heat diffusion.
Innovation Solution
A semiconductor device design utilizing a substrate with an insulating base material and patterned front and back surface metal bodies, where the end portion of the front surface metal body is positioned between the bonding target and the semiconductor element, avoiding contact with the bonding wire and bringing the facing surfaces closer to reduce inductance and thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductive spacer is made thicker to enhance magnetic flux cancellation effects, then inductance is reduced, but thermal resistance increases
Solution Approach 1:
The conductive spacer is divided into a first conductive spacer and a second conductive spacer with different thicknesses. The first conductive spacer has a larger thickness for enhanced magnetic flux cancellation, while the second conductive spacer has a smaller thickness to reduce thermal resistance. This segmentation allows each part to optimize its function independently.
Solution Approach 2:
Different regions of the conductive spacer structure are assigned different thicknesses based on their functional requirements. The first conductive spacer region is made thicker to prioritize inductance reduction, while the second conductive spacer region is made thinner to prioritize heat dissipation. This local quality differentiation resolves the contradiction by allowing spatial variation in spacer thickness.
2Reliability
If cutouts are added to the substrate to avoid bonding wire contact with metal bodies, then electrical isolation is improved, but heat diffusion is inhibited
Solution Approach 1:
An insulating film is introduced as an intermediary layer between the bonding wire and the front surface metal body. This insulating film provides electrical isolation to prevent short circuits, while allowing thermal conduction to maintain heat diffusion pathways. The insulating film acts as a mediator that satisfies both electrical and thermal requirements.
Solution Approach 2:
The substrate structure combines metal bodies for electrical conduction with insulating films for electrical isolation, creating a composite structure. The metal body provides low-resistance electrical paths and thermal conduction, while the insulating film provides electrical isolation. This composite approach resolves the contradiction between electrical isolation and heat diffusion.
3Reliability
If the end portion of the front surface metal body is positioned between the bonding target and semiconductor element, then inductance is reduced by shortening current path, but manufacturing precision requirements increase
Solution Approach 1:
The insulating film is formed on the front surface metal body before the bonding process, preliminarily establishing the isolation structure. This preliminary action ensures that the bonding wire will be electrically isolated from the metal body, allowing the end portion of the metal body to be positioned closer to the semiconductor element for inductance reduction without compromising electrical isolation.
Solution Approach 2:
The insulating film serves as a mediator that enables closer positioning of the metal body end portion to the semiconductor element. By providing electrical isolation, the insulating film allows the metal body to extend closer to reduce inductance while maintaining safe electrical clearance, thus reducing the stringency of manufacturing precision requirements.
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 design effectively reduces thermal resistance and inductance by shortening the heat transfer path and enhancing magnetic flux cancellation, while allowing for efficient heat diffusion from the semiconductor element.
Implementation Method 1
thicker conductive spacers increase magnetic flux cancellation effects
Implementation Method 2
The end portion of the front surface metal body is located between an end portion of a bonding target to which the front surface metal body is bonded and an end portion of the semiconductor element
Data Source
AI summary
A semiconductor device includes a semiconductor element, a first wiring member electrically connected to a first main electrode on a first surface of the semiconductor element, a second wiring member electrically connected to a second main electrode on a second surface of the semiconductor element, a signal terminal connected to a signal pad on the second surface through a bonding wire. The second wiring member includes an insulating base material, a front surface metal body on a front surface of the insulating base material adjacent to the semiconductor element, and a back surface metal body on a back surface. An end portion of the front surface metal body is located between an end portion of a bonding target to which the front surface metal body is bonded and an end portion of the semiconductor element in an arrangement direction of the semiconductor element and the signal terminal.