Reconstituted Wafer Package Field Plate for Leakage Current Stability
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Solution Overview
Problem
Conventional reconstituted wafer level packaging is inadequate for high-voltage components in implantable medical devices, leading to instability in off-state leakage current and leakage runaway due to incompatibility with planar termination structures, especially at elevated temperatures.
Innovation Solution
A reconstituted wafer level package design incorporating a field plate interposed between the die and ball bump array, with a dielectric layer, and a field termination ring, where the field plate is spaced to prevent dielectric breakdown and promote majority carrier accumulation, enhancing leakage current stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional reconstituted wafer level packaging is used for high-voltage components, then miniaturization and compactness are achieved, but off-state leakage current stability deteriorates and leakage runaway occurs at elevated temperatures
Solution Approach 1:
A field plate structure is introduced as an intermediary element between the high-voltage die and the mold compound. This field plate, positioned within the mold compound at a controlled distance from the die, mediates the electric field distribution to prevent direct field effect leakage while maintaining the compact reconstituted wafer level package structure.
Solution Approach 2:
The invention changes the packaging parameters by specifying precise spacing between the field plate and the die (e.g., 0.5mm to 2mm), and by controlling the dielectric properties of the mold compound. These parameter changes optimize the electric field distribution to stabilize leakage current while preserving package miniaturization.
2Reliability
If the field plate is positioned close to the die to prevent leakage, then leakage current stability improves, but dielectric breakdown risk increases
Solution Approach 1:
The invention optimizes the spacing parameter between the field plate and die (e.g., 0.5mm to 2mm) and adjusts the dielectric properties of the mold compound to achieve the right balance. This parameter optimization ensures the field plate is close enough to stabilize leakage current but far enough to prevent dielectric breakdown.
Solution Approach 2:
The field plate structure creates a localized modification of the electric field distribution in the critical region near the die. By concentrating the field control function in this specific location with appropriate spacing and dielectric material properties, the invention stabilizes leakage current without compromising overall dielectric strength.
3Ease of manufacture
If standard reconstituted wafer packaging is used, then manufacturing simplicity is maintained, but compatibility with high-voltage dice and planar termination structures is poor
Solution Approach 1:
The field plate structure serves multiple functions simultaneously: it stabilizes leakage current, controls electric field distribution, and provides a standardized interface for high-voltage dice with planar termination structures. This multi-functionality maintains manufacturing simplicity while improving compatibility with various high-voltage component types.
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 solution provides stable off-state leakage current and prevents field effect leakage, ensuring reliable operation of high-voltage components at room and elevated temperatures, decoupling the field plate spacing from bump dimensions and improving package compatibility with high-voltage dice.
Implementation Method 1
a field plate interposed between the first face of the dice and ball bump array, within the dielectric material
Implementation Method 2
with one or more dielectric layers disposed on the first face... a field plate interposed between the first face of the dice and ball bump array, within the dielectric material
Data Source
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AI summary
A reconstituted wafer level package for a versatile high-voltage capable component is disclosed. The reconstituted wafer package includes a dice substantially encapsulated by a mold material except for a first face. A dielectric layer is disposed on the first face of the dice. The package further includes an array of ball bumps formed on an exterior facing portion of the dielectric layer. Further, a field plate is disposed within the dielectric material and interposed between the first face of the dice and the ball bump array. The field plate may be spaced from the dice by a predetermined distance to prevent dielectric breakdown of the material of the dielectric layer.