the technical fundamentals of semiconductor device thermal testing

The following discussion is a brief introduction to the technical fundamentals of semiconductor device thermal testing using the electrical method of junction temperature measurement. For an in-depth treatment of these topics, download the document entitled The Fundamentals of Thermal Resistance Measurement.

Junction Temperature Sensing Principles
Semiconductor junctions possess useful characteristics for the measurement of junction temperatures. These characteristics are called "temperature sensitive parameters" or TSPs. The most commonly used TSP is the relationship between the forward-biased voltage and the junction temperature in response to a constant, forward current. Using this property, any diode junction can be utilized as a temperature sensor. If the sense-diode junction is part of a semiconductor device, the temperature rise caused by heat dissipation in the device can be measured. This capability forms the basis for a variety of component tests related to the heat dissipation characteristics of the semiconductor devices and their associated packaging.

Sense Junction Calibration
Device calibration is performed with the device immersed in a uniform temperature bath with only the sense-current for the chosen TSP applied. Since the sense-current is too small to cause significant junction-heating the device case temperature will nearly equal the internal junction temperature with a stable bath temperature. By collecting data over a range of bath temperatures, data comprised of sense junction voltage versus junction temperature can often be fit to a straight line. Using this linear calibration relationship, sense junction voltages can be readily converted into the corresponding junction temperatures during powered operation of the device.

Thermal Resistance Test
This test method requires the measurement of device junction temperature during the application of continuous heating power. Thermal resistance is analogous to electrical resistance and defined by the following equation once steady-state thermal equilibrium has been reached:
Rjx = (Tj - Tx) / P
Tj = junction temperature (

英文的，得慢慢看才看得懂了

现在很多有价值的资料都是E文的，看得多了也就习惯了

这个上面讲的thermal diode很多测试都用到，但是不是RTD (Resistance Temperature Detector) 更好些？ 这样self-heating的影响会更小些。

好像具体不同的公司可能会不一样，一般都是参照JEDEC标准