Method for measuring junction-shell thermal resistance of crimping type power semiconductor device
阅读说明:本技术 压接式功率半导体器件结壳热阻的测量方法 (Method for measuring junction-shell thermal resistance of crimping type power semiconductor device ) 是由 王彦刚 齐放 李贺龙 王亚飞 李道会 戴小平 刘国友 于 2018-07-13 设计创作,主要内容包括:本发明提供了一种压接式功率半导体器件结壳热阻的测量方法,包括以下步骤:步骤1.绘制器件电学参数结压降V<Sub>ce</Sub>与结温T<Sub>j</Sub>的关系曲线;步骤2.绘制器件壳表面与散热基板直接压接接触的第一瞬态热阻抗曲线Z<Sub>th-jc(direct)</Sub>(t);步骤3.绘制器件壳表面与散热基板间添加第二接触层时的第二瞬态热阻抗曲线Z<Sub>th-jc(metal)</Sub>(t);步骤4.绘制瞬态热阻抗分离点曲线;步骤5.确定器件结壳热阻。本发明的测量方法能够更便捷地更准确地测量压接式功率半导体器件结壳热阻。(The invention provides a method for measuring junction-shell thermal resistance of a crimping type power semiconductor device, which comprises the following steps: step 1, drawing junction voltage drop V of electrical parameters of a device ce Junction temperature T j The relationship curve of (1); step 2, drawing a first transient thermal impedance curve Z of the direct compression joint contact between the surface of the device shell and the heat dissipation substrate th‑jc(direct) (t); step 3, drawing a second transient thermal impedance curve Z when a second contact layer is added between the surface of the device shell and the heat dissipation substrate th‑jc(metal) (t); step 4, drawing a curve of the transient thermal impedance separation point; and 5, determining the junction-crust thermal resistance of the device. The measuring method can measure the junction-crust thermal resistance of the crimping type power semiconductor device more conveniently and more accurately.)
1. A method for measuring junction thermal resistance of a compression joint type power semiconductor device is characterized by comprising the following steps:
step 1, drawing junction voltage drop V of electrical parameters of a deviceceJunction temperature TjThe relationship curve of (1);
step 2, drawing a first transient thermal impedance curve Z of the direct compression joint contact between the surface of the device shell and the heat dissipation substrateth-jc(direct)(t);
Step 3, drawing a second transient thermal impedance curve Z when a second contact layer is added between the surface of the device shell and the heat dissipation substrateth-jc(metal)(t);
Step 4, drawing a curve of the transient thermal impedance separation point;
and 5, determining the junction-crust thermal resistance of the device.
2. The method for measuring junction-case thermal resistance of the compression-type power semiconductor device according to claim 1, wherein the second contact layer has good electrical conductivity and poor thermal conductivity.
3. The method for measuring junction-case thermal resistance of the compression-type power semiconductor device according to claim 2, wherein the second contact layer is a metal layer.
4. The method for measuring junction thermal resistance of the compression-type power semiconductor device according to claim 2 or claim 3, wherein the second contact layer is in a mesh, hole or sponge structure.
5. The method for measuring junction-case thermal resistance of the compression-type power semiconductor device according to claim 4, wherein the area of the second contact layer is equal to the area of the contact part of the compression-type power semiconductor device, which needs to conduct electricity and heat.
6. The method for measuring junction-case thermal resistance of the compression-type power semiconductor device according to claim 3, wherein the surface of the metal layer is provided with uniformly distributed through hole structures.
7. The method for measuring junction-case thermal resistance of press-fit power semiconductor device according to claim 1, wherein in the step 2, a first transient thermal impedance curve Z is calculated by using the following formulath-jc(direct)(t):
Wherein, Tj(t) represents the junction temperature at each time instant; t iscRepresents the junction temperature T of the test piece at the moment when T is 0jI.e. the shell temperature T of the test piecec。
8. The method for measuring junction-case thermal resistance of press-fit power semiconductor device according to claim 1, wherein in the step 2, the second transient thermal impedance curve Z is calculated by using the following formulath-jc(metal)(t):
Wherein, Tj(t) represents the junction temperature at each time instant; t iscRepresents the junction temperature T of the test piece at the moment when T is 0jI.e. the shell temperature T of the test piecec。
9. The method for measuring junction-shell thermal resistance of compression-type power semiconductor device according to claim 1, wherein in the step 3, a second transient thermal impedance curve Z is measuredth-jc(metal)(t) external pressure applied by the pressure-bonded power semiconductor device and the measured first transient thermal impedance curve Zth-jc(direct)And (t) keeping strict consistency of external pressure applied by the pressure welding type power semiconductor device.
10. The method for measuring junction-case thermal resistance of the compression-type power semiconductor device according to claim 3, wherein the metal layer is made of aluminum, iron, copper, molybdenum or alloy material.
Technical Field
The invention relates to a method for testing junction-crust thermal resistance, in particular to a method for measuring junction-crust thermal resistance of a crimping type power semiconductor device.
Background
Among power semiconductor devices, there are a class of press-fit type package structures, such as transistors, IGBTs, GTOs, and the like. The device is widely applied to high-voltage and high-power application occasions such as high-voltage power transmission of a power system, electric locomotives and the like. The package has the advantages of double-sided package, easy series connection, high reliability, high power density and the like.
Among the characteristics of power semiconductor devices, the heat dissipation characteristic, i.e., the thermal resistance of the device, is an important parameter. The thermal resistance directly determines the current level, voltage level and switching frequency that the power semiconductor device can bear in the application environment, and the required heat dissipation mode. Aiming at the test of the thermal resistance of a power semiconductor device, a transient double-interface method is provided by JEDEC51-14 standard, a measuring device is directly contacted with a radiator, then the device is contacted with the radiator by adopting heat-conducting silicone grease to obtain two groups of transient thermal impedance curves, and the overlapping part and the difference part of the two groups of curves are compared, so that the separation point of the transient thermal impedance curves can accurately reflect the crusting thermal resistance value of the device.
The measuring method is convenient and reliable for measuring the thermal resistance of the TO packaging form or the welding type semiconductor device, but the packaging form of the crimping type power semiconductor device is completely different from the TO packaging form or the welding type semiconductor device, the crimping type power semiconductor device can realize double-sided heat dissipation, working pressure and current are applied TO the crimping type semiconductor device through radiators at two ends of the device, and the current of the semiconductor device is conducted through the radiators. The mounting and fastening force between the test piece and the radiator specified by JEDEC51-14 standard is 10N/cm2On the left and right sides, the separation of two transient thermal impedance curves is not obvious due to excessive pressure, so that an accurate crusting thermal resistance value is difficult to obtain, and external pressure applied by a radiator when the compression-type power semiconductor device works normally is very large, such as: the pressure welding type IGBT device is 1.2kN/cm2On the other hand, this value is much larger than the pressure value between the device and the heat sink specified in the standard, and therefore may eventually lead to erroneous results, so that the above thermal resistance test method is not suitable for measuring the thermal resistance of the junction case of the crimp-type power semiconductor device.
The invention with the application number of CN201310054317.9 provides a junction-crust thermal resistance testing method, which provides an improved method on the transient double-interface method to respectively measure the transient cooling curves of the chip of a semiconductor device to be tested under dry contact and wet contact conditions, so that the temperature distribution of the junction crust of the device to be tested under the dry contact and wet contact test conditions is basically consistent, thereby avoiding the advanced separation of the transient thermal resistance curve caused by the nonlinearity of the material, and obtaining more accurate thermal resistance test results. However, the invention is still directed TO a test method for a TO package and a soldered device, and cannot solve the challenge problem in testing in a press-fit module.
The invention patent with the application number of CN201610258586.0 provides a method and a clamp for measuring the junction-to-shell thermal resistance of a crimping type power semiconductor device, and the measuring clamp designed by the invention meets the measurement requirement of the thermal resistance of a crimping type module by adopting a transient double-interface method. However, the measurement jig involved is complex, and the proposed liquid metal material is not readily available, and the separation point of the obtained transient thermal impedance curve is not readily determinable.
In view of the shortcomings of the existing methods for measuring the thermal resistance of the pressure-bonded power semiconductor device, an improved method for measuring the thermal resistance of the pressure-bonded power semiconductor device more conveniently and more accurately needs to be provided.
Disclosure of Invention
In order to solve the technical problem, the invention provides a method for measuring the junction-to-shell thermal resistance of the pressure-welding type power semiconductor device more conveniently and more accurately.
The invention discloses a method for measuring junction-shell thermal resistance of a crimping type power semiconductor device, which comprises the following steps of:
step 1, drawing junction voltage drop V of electrical parameters of a deviceceJunction temperature TjThe relationship curve of (1);
and 5, determining the junction-crust thermal resistance of the device.
Furthermore, the second contact layer has good electric conductivity and poor heat conduction property, and can be prepared by adopting a material with good electric conductivity and poor heat conduction property.
Furthermore, the second contact layer is a metal layer. Preferably, the second contact layer can be made of metal such as iron, aluminum, copper, molybdenum, or alloy.
Furthermore, the second contact layer is of a net-shaped, hole-shaped or sponge-shaped structure, so that the thermal resistance of the second contact layer is improved as much as possible while the electric conductivity of the second contact layer is met.
Further, the area of the second contact layer is equal to the area of a contact part of the compression joint type power semiconductor device, which needs to conduct electricity and heat.
Furthermore, the second contact layer has good mechanical property, meets the installation requirement of a crimping device, namely can meet the requirement of bearing external pressure of 1.2kN/cm2And (4) the requirements of the left and the right.
Preferably, the surface of the metal layer is provided with a uniformly distributed through hole structure.
Further, in the
Wherein, Tj(t) represents the junction temperature at each time instant; t iscRepresents the junction temperature T of the test piece at the moment when T is 0jI.e. the shell temperature T of the test piecec。
Further, in the
Wherein, Tj(t) represents the junction temperature at each time instant; t iscRepresents the junction temperature T of the test piece at the moment when T is 0jI.e. the shell temperature T of the test piecec。
Compared with the prior art, the method for measuring the junction-shell thermal resistance of the crimping type power semiconductor device has the following advantages:
1. the method for measuring the junction thermal resistance of the crimping type power semiconductor device meets the JEDEC51-14 test standard, can accurately extract the separation point of the transient thermal impedance curve and determine the junction thermal resistance value, is suitable for the traditional thermal resistance test standard, and does not need to purchase equipment or design a clamp again.
2. The second contact layer material required in the method for measuring the junction-shell thermal resistance of the crimping type power semiconductor device is wide in selectivity and easy to obtain, and the structure of the second contact layer material is easy to prepare.
The features mentioned above can be combined in various suitable ways or replaced by equivalent features as long as the object of the invention is achieved.
Drawings
The invention will be described in more detail hereinafter on the basis of non-limiting examples only and with reference to the accompanying drawings. Wherein:
FIG. 1 is a flow chart of a method for measuring junction-to-case thermal resistance of a crimped power semiconductor device according to the present invention;
FIG. 2 is a schematic diagram of a second transient thermal impedance profile measurement configuration with a second contact layer;
fig. 3 is a schematic structural diagram of the second contact layer shown in fig. 2 being a metal layer.
In the drawings, like components are denoted by like reference numerals. The figures are not drawn to scale.
In the figures, the reference numbers are:
1. a crimping power semiconductor device; 2. a special contact layer; 3. a heat-dissipating substrate; 4. the external pressure.
Detailed Description
The invention will be described in further detail below with reference to the drawings and specific examples. It should be noted that, as long as there is no conflict, the embodiments and the features of the embodiments of the present invention may be combined with each other, and the technical solutions formed are within the scope of the present invention.
As shown in fig. 1, the method for measuring junction-to-case thermal resistance of a crimping power semiconductor device of the invention comprises the following steps:
step 1, drawing junction voltage drop V of electrical parameters of a deviceceJunction temperature TjThe relationship curve of (1);
Wherein the first transient thermal impedance curve Zth-jc(direct)(t) is calculated using the formula:
wherein, Tj(t) represents the junction temperature at each time instant; t iscRepresents the junction temperature T of the test piece at the moment when T is 0jI.e. the shell temperature T of the test piecec。
Second transient thermal impedance curve Zth-jc(metal)(t) is calculated using the formula:
drawing a second transient thermal impedance curve Z when a second contact layer is added between the surface of the device shell and the heat dissipation substrateth-jc(metal)(t) second transient thermal impedance curve Zth-jc(metal)(t) and stepFirst transient thermal impedance curve Z in step 2th-jc(direct)(t) similarly, compared with the
a second contact layer is added between the surface of the device shell and the
And 5, determining the junction-crust thermal resistance of the device.
And determining the separation point of the transient thermal impedance separation point curve through a separation point criterion to obtain the thermal resistance value of the device crust.
The invention relates to a formula and a curve drawing method, such as the voltage drop V of the electrical parameter junction of a deviceceJunction temperature TjThe drawing of the relation curve, the drawing of the transient thermal impedance separation point curve and the formula for obtaining the thermal resistance value of the crust through the separation point can be obtained by the method and the calculation formula in the JEDEC51-14 standard.
As shown in fig. 2, which is a schematic diagram of a second transient thermal impedance curve measurement structure with a second contact layer, a first transient thermal impedance curve Z is obtained when the direct compression contact between the compression-bonded power semiconductor device 1 and the
Then, the first transient thermal impedance curve Z is contrastively analyzedth-jc(direct)(t) second transient thermal impedance Curve Zth-jc(metal)And (t) drawing a transient thermal impedance separation point curve, extracting separation points and determining the junction thermal resistance value of the compression joint type power semiconductor device 1.
In one embodiment, the
In a preferred embodiment, the
In one embodiment, the surface of the metal layer adopts a structure of uniformly distributed through
In a more preferred embodiment, the metal layer may be made of a metal or alloy of iron, aluminum, copper, molybdenum, etc.
The method for measuring the junction thermal resistance of the crimping type power semiconductor device meets the JEDEC51-14 test standard, can accurately extract the separation point of the transient thermal impedance curve and determine the junction thermal resistance value, is suitable for the traditional thermal resistance test standard, and does not need to purchase equipment or design a clamp again. The second contact layer material has wide selectivity and is easy to obtain, and the structure is easy to prepare. The measuring method can measure the junction-crust thermal resistance of the pressure-welding type power semiconductor device more conveniently and more accurately.
While the invention has been described with reference to a preferred embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the technical features mentioned in the embodiments can be combined in any way as long as no conflict exists. It is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.