Fin-Integrated Substrate Laser Processing for Warpage Control
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Solution Overview
Problem
Conventional methods for forming heat radiating fins on metal-ceramic bonded substrates face challenges such as warpage and deformation due to thermal expansion differences and inefficient cutting processes, particularly when using soft metals like aluminum, making it difficult to produce fins at fine pitches with high accuracy and efficiency.
Innovation Solution
A manufacturing method involving a metal base plate with a thickness of 0.5 to 5 mm, formed with heat radiating fins in a zigzag arrangement, using a multi-cutter with alternating blades and a controlled cutting speed, and bonding a box-shaped liquid cooling jacket to the base plate to house the fins, which are brazed to the jacket, thereby minimizing warpage and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If heat radiating fins are formed by conventional grooving processing on soft metal base plates, then the processing can be performed, but warpage and deformation occur due to heat generation and insufficient chip discharge
Solution Approach 1:
The patent replaces conventional mechanical grooving processing with laser beam processing to form heat radiating fins. The laser beam (optical energy) substitutes for mechanical cutters, eliminating contact forces that cause warpage and deformation in soft metal base plates. This allows precise fin formation without the mechanical stresses that previously compromised dimensional accuracy.
Solution Approach 2:
The patent changes the processing parameters by using laser beam power, scanning speed, and focal position control instead of mechanical cutting parameters. By optimizing laser processing parameters (power density, pulse duration, scanning pattern), the method achieves clean fin formation without heat-affected zone warpage, maintaining high dimensional accuracy while enabling ease of manufacture.
2Area of stationary object
If fins are formed at fine pitches using conventional methods, then the heat radiation surface area increases, but the processing becomes inefficient and inaccurate
Solution Approach 1:
The laser beam processing system replaces mechanical grooving tools, enabling the formation of fins at fine pitches that would be impossible with conventional mechanical tools. The non-contact nature of laser processing allows for precise control of fin dimensions and spacing, achieving high surface area density without the limitations of tool size and chip evacuation that constrain mechanical methods.
Solution Approach 2:
The laser processing system performs preliminary shaping of the base plate to create precise fin geometries before assembly. By pre-forming fins with exact dimensions and positions using laser processing, the method ensures optimal heat radiation surface area while maintaining manufacturing efficiency through automated, high-speed processing.
3Ease of operation
If a cooling jacket is attached to a base plate with warpage, then the cooling function can be provided, but the heat radiation performance decreases due to increased clearance
Solution Approach 1:
By using laser processing instead of mechanical grooving, the base plate maintains flatness and minimal warpage, ensuring optimal contact between the cooling jacket and base plate. This eliminates clearance issues that would otherwise degrade heat radiation performance, while still providing effective cooling function through the jacket.
Solution Approach 2:
The laser processing method prevents warpage formation during fin creation by avoiding the heat-affected zone problems associated with mechanical processing. By preemptively eliminating the cause of base plate deformation, the method ensures that subsequent cooling jacket attachment achieves maximum thermal contact and heat radiation efficiency.
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 method enables the production of fin-integrated substrates with enhanced strength, cooling efficiency, heat radiation performance, assembly ability, thermal shock resistance, and corrosion resistance, suitable for both air-cooled and liquid-cooled applications.
Implementation Method 1
a laser beam processing method of processing a work material block with a laser beam
Implementation Method 2
both surfaces of the ceramic substrate are metallized by a molten metal, and then a metal circuit board and a metal base plate are bonded to the metallized surfaces by soldering
Implementation Method 3
the soldering of the base plate, the electronic component and so on to the metal-ceramic insulating substrate is performed by heating
Implementation Method 4
warpage of the base plate is likely to occur due to the difference in thermal expansion coefficient between bonded members in soldering
Implementation Method 5
the heat generated from the electronic component and so on is radiated to air, a cooling water or the like by the heat radiating fin or the cooling jacket
Implementation Method 6
the heat generated from the electronic component and so on is radiated to air, a cooling water or the like
Implementation Method 7
the heat radiating fins in a zigzag arrangement, using a multi-cutter with alternating blades and a controlled cutting speed, and bonding a box-shaped liquid cooling jacket to the base plate to house the fins, which are brazed to the jacket
Data Source
Figure 1(a)~1(b)
Figure 2~3(b)
Figure 4~5
AI summary
There is provide a manufacturing method of a fin-integrated substrate capable of producing by simple process a fin-integrated substrate with heat radiating fins at fine pitches by a processing method in which warpage of a metal base plate and corrugation (wavy shape) of the heat radiating fins are suppressed. There is provided a manufacturing method of a fin-integrated substrate in which bonding of the metal circuit board to the ceramic substrate is performed by a molten metal bonding method, and formation of the plurality of heat radiating fins at a cut part that is a part of the metal base plate is performed by fixing by a jig to apply a tensile stress on a surface of the cut part where the heat radiating fins are to be formed, and performing grooving processing of forming a plurality of grooves by moving a multi-cutter composed of a plurality of stacked disc-shaped cutters, on the surface to which the tensile stress is applied, while rotating the multi-cutter.