Power Module Laminate Structure for Clearer SAT Inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Scanning Acoustic Tomography (SAT) inspectability is deteriorated due to multiple reflected waves when ultrasonic waves are emitted through a resin layer in electronic devices with multiple layers, leading to reduced effectiveness in flaw detection.
Innovation Solution
The laminated structure of the electronic device is designed such that the time period for an ultrasonic pulse to travel two or three roundtrips in the second conductor layer is longer than the time for one roundtrip in the range from the second conductor layer to the element, and the time for one roundtrip through the second conductor layer, resin layer, and first conductor layer is longer than two roundtrips through the second conductor layer, thereby suppressing multiple reflected waves and improving SAT inspectability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laminated structure with resin layer is used in electronic device, then electrical insulation and structural integrity are improved, but multiple reflected waves occur in SAT inspection causing inspectability deterioration
Solution Approach 1:
The patent applies parameter changes by carefully controlling the thickness of the resin layer and conductor layers to satisfy specific ultrasonic pulse travel time relationships. By adjusting these dimensional parameters, the structure suppresses multiple reflected waves while maintaining electrical insulation and structural integrity, thus resolving the contradiction between reliability and measurement precision.
2Adaptability or versatility
If conductor layers are added for electrical connectivity, then electrical functionality is improved, but ultrasonic wave reflections increase reducing inspection quality
Solution Approach 1:
The patent resolves this contradiction by optimizing the thickness parameters of conductor layers and resin layers. By satisfying specific ultrasonic travel time conditions through parameter adjustment, the design maintains necessary electrical functionality while minimizing ultrasonic reflections that degrade inspection quality.
3Reliability
If resin layer thickness is increased for better insulation, then electrical insulation is improved, but ultrasonic pulse travel time increases causing multiple reflections to enter inspection gate
Solution Approach 1:
The patent applies parameter changes by optimizing the resin layer thickness to satisfy specific ultrasonic travel time relationships. This optimization ensures adequate electrical insulation while preventing multiple reflected waves from entering the inspection gate within the measurement window, thus resolving the contradiction between insulation quality and time loss.
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 configuration enhances the inspectability of Scanning Acoustic Tomography by reducing the impact of multiple reflections, allowing for effective flaw detection in laminated portions with various configurations.
Implementation Method 1
the ultrasonic waves may reflect each boundary of the layers and this reflection at the boundary may deteriorate an ability of inspecting the object
Implementation Method 2
a time period in which an ultrasonic pulse emitted from outside the second conductor layer toward the element travels two roundtrips in the second conductor layer
Data Source
AI summary
A power module comprises an element and an insulated circuit board having a laminated portion. The laminated portion includes a first metal layer, a bonding layer interposed between an element and the first metal layer, a second metal layer, and a resin layer interposed between the first metal layer and the second metal layer. The insulated circuit board has a pair of laminated portions provided so as to sandwich the element. The laminated portions are configured so that ultrasonic pulses emitted from an outside of the second metal layer toward the element have the following relationship of detection time periods. A time period in which the ultrasonic pulse travels two roundtrips in the second metal layer is longer than a time period in which the ultrasonic pulse travels one roundtrip in a range from the second metal layer to the element.