Isolated Temperature Sensor Package With Spacer Dielectric
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Solution Overview
Problem
Semiconductor temperature sensors face failures due to dielectric breakdown when exposed to high voltages, necessitating electrical isolation while maintaining thermal coupling, which existing technologies, such as optical sensors, do not adequately address in all applications.
Innovation Solution
A semiconductor device package with a spacer dielectric providing thermal conductivity and electrical isolation, where a semiconductor die with a temperature sensor is thermally coupled to a high-voltage surface while being electrically isolated from it, using a package substrate with exposed leads for terminal formation and encapsulation with mold compound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the semiconductor temperature sensor is directly exposed to high voltage for temperature sensing, then the temperature sensing capability is improved, but the reliability deteriorates due to dielectric breakdown
Solution Approach 1:
The patent introduces a spacer dielectric as an intermediary element between the high voltage conductor and the semiconductor temperature sensor. This dielectric spacer provides electrical isolation to prevent dielectric breakdown while maintaining thermal coupling through its thermally conductive properties, thus protecting the sensor from high voltage damage while enabling temperature sensing
2Reliability
If electrical isolation is implemented using optical sensors, then the reliability is improved by preventing dielectric breakdown, but the adaptability deteriorates because not all applications provide appropriate optical sensing signals
Solution Approach 1:
The spacer dielectric serves as a universal intermediary that provides electrical isolation through its inherent dielectric properties rather than requiring application-specific optical signaling mechanisms. This approach maintains reliability across diverse high voltage applications without depending on the presence of appropriate optical sensing signals
Solution Approach 2:
The invention changes the isolation mechanism from optical signal-dependent to dielectric property-based, allowing the temperature sensor to operate reliably in high voltage environments regardless of the specific application conditions or signal types available
3Measurement precision
If the semiconductor die is thermally coupled to the high voltage surface, then the temperature measurement accuracy is improved, but the electrical isolation is compromised leading to dielectric breakdown
Solution Approach 1:
The dielectric spacer acts as a mediator that enables thermal coupling between the semiconductor die and the high voltage surface while simultaneously providing electrical isolation. The spacer's thermal conductivity allows accurate temperature measurement, while its dielectric properties block the harmful electric field from reaching the semiconductor die
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 effectively protects the semiconductor die from high-voltage electric fields, allowing reliable temperature sensing without dielectric breakdown, as demonstrated by simulations showing reduced electric fields within the semiconductor die even under high voltage conditions.
Implementation Method 1
a spacer dielectric providing thermal conductivity and electrical isolation, where a semiconductor die with a temperature sensor is thermally coupled to a high-voltage surface while being electrically isolated from it
Implementation Method 2
a spacer dielectric providing thermal conductivity and electrical isolation, where a semiconductor die with a temperature sensor is thermally coupled to a high-voltage surface while being electrically isolated from it
Data Source
AI summary
In a described example, an apparatus includes: a package substrate having a die pad configured for mounting a semiconductor die, a first lead connected to the die pad, and a second lead spaced from and electrically isolated from the die pad; a spacer dielectric mounted on the die pad; a semiconductor die including a temperature sensor mounted on the spacer dielectric; electrical connections coupling the semiconductor die to the second lead; and mold compound covering the semiconductor die, the die pad, the electrical connections, and a portion of the package substrate, with portions of the first lead and portions of the second lead exposed from the mold compound to form terminals for a packaged temperature sensor device.