Wire Bond Free Power Module with Double-Sided Cooling
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Solution Overview
Problem
Existing semiconductor power modules face challenges in assembling multiple packages for high voltage and high current applications in hostile thermal and mechanical environments, requiring efficient cooling and reliable connections while maintaining access to device terminals.
Innovation Solution
A novel assembly of flat, double-sided cooled semiconductor packages with embedded die, where packages are stacked in a parallel array and connected via a comb-shaped conductive clip, allowing for immersion in a coolant chamber for effective thermal management and circuit formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple semiconductor packages are assembled in parallel array for high voltage and high current applications, then the circuit capability and power handling are improved, but the assembly complexity and device terminals accessibility are worsened
Solution Approach 1:
Multiple semiconductor packages are assembled in a parallel array configuration and interconnected through a common support structure, merging their thermal and mechanical support functions while maintaining electrical isolation. This allows high voltage and high current circuits to be formed without proportionally increasing assembly complexity.
Solution Approach 2:
The common support structure serves multiple functions simultaneously: it provides mechanical support for multiple packages, acts as a thermal management interface, and enables electrical interconnections. This multi-functionality reduces the number of separate components needed and simplifies the overall assembly process.
2Temperature
If packages are cooled from both sides with DBC wafers, then the thermal management efficiency is improved, but the package structure complexity and manufacturing difficulty are worsened
Solution Approach 1:
The cooling function is segmented into two independent DBC (direct bonded copper) wafers, one bonded to each side of the semiconductor die. This allows thermal management from both sides simultaneously while keeping each DBC wafer as a separate, manufacturable component that can be processed independently before final assembly.
Solution Approach 2:
DBC wafers utilize composite material construction with copper layers bonded to ceramic or metal substrates, providing both thermal conductivity and electrical isolation properties. This composite structure enables effective thermal management while maintaining electrical integrity and facilitating manufacturing through standardized material layers.
3Temperature
If packages are suspended in coolant chamber for immersion cooling, then the cooling effectiveness is improved, but the mechanical stress and reliability in hostile environments are worsened
Solution Approach 1:
The semiconductor packages are suspended within the coolant chamber in a nested configuration, with packages positioned inside the cooling environment rather than mounted on external heat sinks. This nesting approach maximizes thermal contact with the coolant while protecting the packages from mechanical stress through the supportive chamber structure.
Solution Approach 2:
The coolant chamber acts as an intermediary between the semiconductor packages and the external environment, providing thermal management while isolating the packages from mechanical stresses. The chamber structure mediates the thermal transfer and protects the delicate electronic components from hostile environmental conditions.
4Device complexity
If lead frame terminals connect like terminals together over the cover, then the circuit formation is simplified, but the electrical insulation and thermal communication requirements are worsened
Solution Approach 1:
Lead frame terminals serve as intermediary conductors that connect like terminals from multiple packages together while traversing over the cover structure. These lead frames are designed with appropriate insulation and routing to prevent electrical breakdown while maintaining thermal pathways, mediating between the electrical connection need and the insulation requirement.
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 solution enables the creation of reliable, high current, high voltage circuits that can be easily assembled and mounted in automotive or similar applications, providing efficient cooling and convenient access to terminals, thus addressing the challenges of thermal and mechanical stress in harsh environments.
Implementation Method 1
packages are stacked in a parallel array with their terminals extending from a single perpendicular plane. A common support structure, for example, the cover of a coolant container body, receives the terminal end of the packages, the bodies of which may be suspended in a coolant chamber.
Implementation Method 2
The comb-shaped clip may then be immersed in a fluid (air or liquid) cooling chamber with the terminals of each package protruding from the top of the chamber.
Implementation Method 3
parallel opposite metal surfaces which are in good thermal communication with the opposite surface of one or more semiconductor die sandwiched between two direct bonded copper (DBC) wafers
Data Source
AI summary
A wire bond free power module assembly consists of a plurality of individual thin packages each consisting of two DBC wafers which sandwich one or more semiconductor die. The die electrodes and terminals extend through one insulation covered end of the wafer sandwich and the outer sides of the sandwiches are the outer copper plates of the DBC wafers which are in good thermal communication with the semiconductor die but are electrically insulated therefrom. The plural packages may be connected in parallel by lead frames on the terminals and the packages are stacked with a space between them to expose both sides of all packages to a cooling medium, either the fingers of a conductive comb or a fluid heat exchange medium.