Semiconductor Insulating Substrate with Asymmetric Conductor Thickness
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Solution Overview
Problem
Semiconductor devices with high current density face challenges in balancing weight reduction and maintaining structural strength, particularly in heat dissipation and manufacturing cost, as increasing the thickness of the circuit pattern adds weight without significantly improving heat radiation, and reducing the base plate thickness compromises the device's strength.
Innovation Solution
The semiconductor device incorporates an insulating substrate with a thicker upper conductor portion and a thinner lower conductor portion, along with a collar portion and mounting holes for a cooler, to enhance rigidity and disperse external forces, while reducing weight by optimizing the thickness of the base plate and using a sealing material to secure the components within a case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thickness of the circuit pattern of the insulating substrate is increased to improve heat dissipation, then heat dissipation performance is improved, but the weight of the insulating substrate increases
Solution Approach 1:
The conductor portion is designed with non-uniform thickness, being thicker in the heat generation area (under the semiconductor chip) and thinner in other areas. This local variation in thickness allows concentrated heat dissipation where needed while minimizing the overall weight of the insulating substrate.
2Weight of stationary object
If the thickness of the base plate of the insulating substrate is reduced to decrease weight, then weight is reduced, but the strength of the junction between the case and the base plate becomes insufficient
Solution Approach 1:
The base plate thickness is optimized locally: thinner in areas where strength is not critical (reducing overall weight) and thicker or reinforced at the junction areas with the case (maintaining structural strength). The conductor portion itself is designed to provide structural reinforcement at key locations.
3Temperature
If a heat spreader is provided under the IGBT chip to improve heat dissipation, then heat dissipation performance is improved, but assembly time increases and manufacturing cost increases
Solution Approach 1:
The heat dissipation function previously requiring a separate heat spreader component is merged into the insulating substrate itself. The conductor portion of the insulating substrate serves dual purposes: electrical conduction and heat dissipation, eliminating the need for an additional heat spreader layer and simplifying the assembly process.
4Weight of stationary object
If the thickness of the lower conductor portion is reduced to decrease weight, then weight is reduced, but heat dissipation capability may be compromised
Solution Approach 1:
The lower conductor portion thickness is optimized based on local heat dissipation requirements. Areas directly under heat-generating semiconductor chips have sufficient thickness for effective heat dissipation, while other areas of the lower conductor portion can be thinner, reducing overall weight while maintaining necessary thermal 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 design effectively reduces the weight of the semiconductor device while ensuring necessary strength and improved heat dissipation, dispersing stress and external forces to prevent damage to the insulating layer, thus addressing the balance between weight reduction and structural integrity.
Implementation Method 1
The upper conductor portion has a thickness larger than a thickness of the lower conductor portion. The upper conductor portion includes a circuit pattern on which the semiconductor chips are disposed and an outer peripheral pattern provided on an outer peripheral side of the circuit pattern at a certain gap. The outer peripheral pattern of the upper conductor portion, an outer peripheral portion of the insulating layer, and the outer peripheral portion of the lower conductor portion are fixed into a concave portion formed in the inner peripheral portion of the peripheral wall portion of the case.
Implementation Method 2
The upper conductor portion has a thickness larger than a thickness of the lower conductor portion. The outer peripheral pattern of the upper conductor portion, an outer peripheral portion of the insulating layer, and the outer peripheral portion of the lower conductor portion are fixed into a concave portion formed in the inner peripheral portion of the peripheral wall portion of the case. Therefore, the concave portion of the peripheral wall portion of the case and the outer periphery of the insulating substrate whose rigidity is enhanced by providing the outer peripheral pattern can be fixed. Thus, external force applied to the semiconductor device can be dispersed, and damage to the insulating layer can be suppressed.
Implementation Method 3
The sealing material seals the case inside. The outer peripheral pattern of the upper conductor portion, an outer peripheral portion of the insulating layer, and the outer peripheral portion of the lower conductor portion are fixed into a concave portion formed in the inner peripheral portion of the peripheral wall portion of the case.
Implementation Method 4
A collar portion protruding outward from an outer peripheral portion of the peripheral wall portion of the case is formed. Mounting holes, through which a cooler is attachable, are formed on the collar portion.
Data Source
AI summary
An upper conductor portion having a thickness A larger than a thickness B of a lower conductor portion, the upper conductor portion including a circuit pattern on which semiconductor chips are disposed and an outer peripheral pattern provided on an outer peripheral side of the circuit pattern at a certain gap, the outer peripheral pattern of the upper conductor portion, an outer peripheral portion of an insulating layer, and an outer peripheral portion of the lower conductor portion are fixed to a concave portion formed in the inner peripheral portion of the peripheral wall portion of a case, a collar portion projecting outward from the outer peripheral portion of the peripheral wall portion of the case is formed, and the attachment holes, through which the radiation fins are attachable, are formed in the collar portion.