CN116090261A - Stress field reconstruction method and system for crimping type power semiconductor device - Google Patents
Stress field reconstruction method and system for crimping type power semiconductor device Download PDFInfo
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Abstract
The invention belongs to the technical field of semiconductor measurement, and provides a stress field reconstruction method and a stress field reconstruction system for a crimping type power semiconductor device, wherein the method comprises the following steps: constructing a stress field distribution calculation model; obtaining a contact parameter measurement average value of each sub-module in the crimping type power semiconductor device; obtaining the contact parameters of each sub-module in the crimping type power semiconductor device to calculate the average value; when the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device do not meet the preset constraint condition, the numerical value of the preset height value is adjusted by utilizing a preset optimizing algorithm until the preset constraint condition is met, and the corresponding preset height value is obtained. The invention can realize the accurate modeling of the actual stress field distribution of the crimping type power semiconductor device, so as to consider the height of the device assembly, realize the reconstruction of the internal stress field of the device and accurately calculate the internal electrothermal characteristic distribution.
Description
Technical Field
The invention belongs to the technical field of semiconductor measurement, and particularly relates to a stress field reconstruction method and a stress field reconstruction system for a crimping type power semiconductor device.
Background
The crimp type power semiconductor device uses electrode plates to connect chips in parallel on a large scale, and maintains electrical connection by pressure applied to the electrode plates. The high-voltage high-current operation requirement of the flexible direct-current transmission equipment is met, and the failure short circuit mode of the device also provides necessary guarantee for safe and reliable operation of the flexible direct-current transmission equipment. The crimping type power semiconductor device is usually formed by connecting a plurality of sub-modules in parallel, and the heights of the sub-modules are different due to the manufacturing heights of the layers of materials, so that the stress distribution inside the device is affected. The internal stress distribution of the device directly determines the electrothermal characteristics of each sub-module. Therefore, in order to accurately calculate the internal electric heating distribution of the device, the modeling process needs to consider the influence of the dispersion of the heights of the sub-modules in the device on the internal stress distribution of the device.
The high-voltage high-power crimping type power semiconductor device is generally formed by connecting tens of sub-modules in parallel, and each sub-module is electrically connected by multilayer conductive materials through external pressure. The multi-chip parameter difference can cause uneven internal stress and temperature distribution of the device, which directly threatens the reliability of the crimping type power semiconductor device, and the multi-physical field modeling simulation analysis is an effective means for solving the problem. However, in the compression-joint type power semiconductor device multi-physical coupling model, an ideal device three-dimensional model is mostly used for qualitatively analyzing the internal stress distribution rule of the device, and it is difficult to accurately calculate the electric heating distribution in the actual multi-chip device. The height dispersibility of each sub-module in the crimping type power semiconductor device is large, the height distribution is as small as tens of nanometers, the size of each module is difficult to accurately measure by the existing measuring method, the three-dimensional model of the crimping type power semiconductor device is difficult to accurately construct, and the calculation result of the internal stress field distribution of the device is directly influenced.
In the prior art, the heights of all sub-modules in the device are manually assigned, the height difference of all the sub-modules in the device is simulated, the internal stress distribution of the device is qualitatively analyzed, the simulation result can only be applied to the simulation analysis of the electric heating characteristics of an ideal device without considering the heights, and the influence of the stress non-uniformity caused by the actual height dispersion on the electric heating characteristic distribution of the device can not be analyzed.
Disclosure of Invention
In order to solve at least one technical problem in the background technology, the invention provides a stress field reconstruction method and a stress field reconstruction system for a crimping type power semiconductor device, wherein the stress field reconstruction method and the stress field reconstruction system take the average value of the sub-group contact parameters of the crimping type power semiconductor device, which are measured by pressure test paper, as a target, estimate the heights of the sub-groups in the crimping type power semiconductor device through finite element calculation and optimization algorithm, and complete the stress field reconstruction of the crimping type power semiconductor device after the constraint condition is reached.
According to a first aspect of the present invention, there is provided a stress field reconstruction method for a crimping type power semiconductor device, the method comprising:
constructing a stress field distribution calculation model, wherein the stress field distribution calculation model is used for calculating and obtaining a contact parameter calculation average value of a compression-joint type power semiconductor device according to a preset pressure value applied to the compression-joint type power semiconductor device and a preset height value of each sub-module in the compression-joint type power semiconductor device;
applying pressure with the magnitude of the measured pressure value to the crimping type power semiconductor device to obtain a contact parameter measurement average value of each sub-module in the crimping type power semiconductor device;
inputting the measured pressure value of the crimping type power semiconductor device into the stress field distribution calculation model as a preset pressure value to obtain the contact parameter calculation average value of each sub-module in the crimping type power semiconductor device;
when the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device do not meet a preset constraint condition, the numerical value of a preset height value in the stress field distribution calculation model is adjusted by utilizing a preset optimizing algorithm until the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet the preset constraint condition, and a corresponding preset height value is obtained.
Further, the stress field distribution calculation model comprises a first sub-model and a second sub-model, wherein the first sub-model is used for calculating and obtaining the stress distribution of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of the crimping type power semiconductor device;
the second sub-model is used for calculating and obtaining a contact parameter calculation average value of the crimping type power semiconductor device according to stress distribution of the crimping type power semiconductor device;
correspondingly, after the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet a preset constraint condition and obtain a corresponding preset height value, the method further comprises:
and according to the measured pressure value of the crimping type power semiconductor device, obtaining the stress distribution of the crimping type power semiconductor device by using the updated first sub-model.
Further, the contact parameter calculation average value is used for representing a contact pressure calculation average value or a contact force calculation average value;
the contact parameter measurement average is used to characterize a contact pressure measurement average or a contact force measurement average.
Further, when the contact parameter measurement average value is used for representing a contact pressure measurement average value, the applying the pressure with the magnitude being the measured pressure value to the crimping type power semiconductor device, and obtaining the contact parameter measurement average value of the crimping type power semiconductor device includes:
placing pressure test paper in the pressure-welding type power semiconductor device, and applying pressure with the magnitude of the measured pressure value to the pressure-welding type power semiconductor device;
after stopping applying pressure to the crimping type power semiconductor device, performing image acquisition on the pressure test paper, and obtaining an image corresponding to the pressure test paper;
and according to the image corresponding to the pressure test paper, obtaining a contact pressure measurement average value of each sub-module in the crimping type power semiconductor device by utilizing a preset functional relation.
Further, the obtaining, according to the image corresponding to the pressure test paper and using a preset functional relationship, a measurement average value of a contact parameter of the crimping power semiconductor device includes:
partitioning the image according to each sub-module of the crimping type power semiconductor device;
carrying out graying treatment on the partitioned image to obtain a gray average value of each sub-module of the crimping type power semiconductor device;
obtaining the average color density of each sub-module of the crimping type power semiconductor device according to the gray average value of each sub-module of the crimping type power semiconductor device and the functional relation between the color density and the gray value;
and obtaining the contact parameter measurement average value of the crimping type power semiconductor device according to the average color density of each sub-module of the crimping type power semiconductor device and the functional relation between the pressure intensity and the color density.
Further, the functional relation between the color density and the gray value is obtained by curve fitting the relation between the color density and the gray value;
the functional relationship of the pressure and the color density is obtained by curve fitting the relationship of the pressure and the color density.
Further, the preset constraint condition includes: and the relative error between the calculated average value of the contact parameters and the measured average value of the contact parameters of each sub-module in the crimping type power semiconductor device is less than 10%.
Further, the preset constraint condition further includes: and calculating the average value of the contact parameters of each sub-module in the crimping type power semiconductor device and judging whether the square difference of the average value of the contact parameter measurement is the minimum value or not.
Further, when the contact parameter measurement average value is used for representing a contact force measurement average value, the applying a pressure with a magnitude being a measurement pressure value to the crimping type power semiconductor device, and obtaining the contact parameter measurement average value of the crimping type power semiconductor device includes:
the contact force measurement average value is measured by a mechanical sensor.
According to a second aspect of the present invention, there is also provided a stress field reconstruction system for a crimped power semiconductor device, the system comprising:
the model construction module is used for constructing a stress field distribution calculation model, wherein the stress field distribution calculation model is used for calculating and obtaining a contact parameter calculation average value of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of each sub-module in the crimping type power semiconductor device;
the contact parameter measurement average value acquisition module is used for applying pressure with the size of a measurement pressure value to the crimping type power semiconductor device to obtain the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device;
the contact parameter calculation average value obtaining module is used for inputting the measured pressure value of the crimping type power semiconductor device into the stress field distribution calculation model as a preset pressure value to obtain the contact parameter calculation average value of each sub-module in the crimping type power semiconductor device;
and the preset height value acquisition module is used for adjusting the numerical value of the preset height value in the stress field distribution calculation model by utilizing a preset optimizing algorithm when the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device do not meet the preset constraint condition until the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet the preset constraint condition, and obtaining the corresponding preset height value.
The invention realizes the following technical effects:
(1) The method can consider the height of the device component, realize the accurate modeling of the actual stress field distribution of the crimping type power semiconductor device, and accurately calculate the internal electric heating characteristic distribution;
(2) The invention can also output the height distribution of each sub-module in the device, and provide guidance for the packaging optimization design of the device.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort to a person skilled in the art.
FIG. 1 is a schematic diagram of a stress field reconstruction method for a crimping type power semiconductor device in the present invention;
fig. 2 is a schematic diagram of a stress field reconstruction system for a crimping type power semiconductor device in the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Fig. 1 is a schematic diagram of a stress field reconstruction method of a compression-type power semiconductor device according to an embodiment of the present invention, and as shown in fig. 1, the stress field reconstruction method of the compression-type power semiconductor device includes:
step S101, a stress field distribution calculation model is constructed, wherein the stress field distribution calculation model is used for calculating and obtaining a contact parameter calculation average value of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of each sub-module in the crimping type power semiconductor device;
step S102, applying pressure with the magnitude of a measured pressure value to a crimping type power semiconductor device to obtain a contact parameter measurement average value of each sub-module in the crimping type power semiconductor device;
step S103, inputting the measured pressure value of the crimping type power semiconductor device into a stress field distribution calculation model as a preset pressure value to obtain a contact parameter calculation average value of all sub-modules in the crimping type power semiconductor device;
step S104, when the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the compression-type power semiconductor device do not meet the preset constraint condition, the numerical value of the preset height value in the stress field distribution calculation model is adjusted by utilizing a preset optimizing algorithm until the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the compression-type power semiconductor device meet the preset constraint condition, and the corresponding preset height value is obtained.
In this embodiment, a crimping type semiconductor device that can realize a stress field reconstruction method of the crimping type power semiconductor device includes: a power semiconductor device including a contact surface is commonly used for a crimp-type IGBT device, a crimp-type SiC device, a thyristor device, and the like.
The stress field reconstruction of the crimping type power semiconductor device comprises the following steps:
establishing a stress field distribution calculation model by using finite element simulation software, wherein the stress field distribution calculation model is used for calculating stress field distribution of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of each sub-module in the crimping type power semiconductor device, and calculating a contact parameter calculation average value of the crimping type power semiconductor device according to the stress field distribution of the crimping type power semiconductor device; the preset pressure value applied to the crimping type power semiconductor device can also be used for measuring a contact parameter measurement average value, for example, the contact pressure measurement average value is measured by using a pressure test paper or a pressure sensor according to the preset pressure value applied to the crimping type power semiconductor device.
And applying pressure with the magnitude of the measured pressure value to the crimping type power semiconductor device to obtain the average value of the contact parameter measurement of each sub-module in the crimping type power semiconductor device.
The stress field distribution calculation model comprises a first sub-model and a second sub-model, wherein the first sub-model is used for calculating and obtaining the internal stress field distribution of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of each sub-module in the crimping type power semiconductor device; the preset height value can be a group of same values or a group of different values;
the second sub-model is used for obtaining the calculation average value of the sub-module contact pressure inside the crimping type power semiconductor device according to the internal stress field distribution of the crimping type power semiconductor device, for example, obtaining the calculation average value of the sub-module contact pressure inside the crimping type power semiconductor device according to the internal stress field distribution of the crimping type power semiconductor device;
when the contact pressure calculation average value and the contact pressure measurement average value of each sub-module in the compression-type power semiconductor device do not meet the preset constraint condition, the numerical value of the preset height value in the stress field distribution calculation model is adjusted by utilizing a preset optimizing algorithm until the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the compression-type power semiconductor device meet the preset constraint condition, and the corresponding preset height value is obtained.
The contact parameter calculation average value and the contact parameter measurement average value can be selected according to actual requirements, wherein the parameters can be pressure, contact force or other parameters. When the contact parameter measurement average value is the contact force pressure measurement average value, the contact force pressure measurement average value can be obtained through a pressure test paper or a mechanical sensor, and the specific method can be selected according to actual requirements.
Alternatively, the constraint condition may be set according to the actual situation, for example, a relative error between a contact pressure calculation average value and a contact pressure measurement average value of each sub-module inside the crimping type power semiconductor device is less than 10%, and whether a difference square between the contact pressure calculation average value and the contact pressure measurement average value of each sub-module inside the crimping type power semiconductor device is a minimum value;
the optimization algorithm may be cobyloa, gradient optimization, particle swarm optimization, neural network, or other algorithms. And after the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet the preset constraint condition and the corresponding preset height value is obtained, obtaining the stress distribution of the crimping type power semiconductor device according to the measured pressure value of the crimping type power semiconductor device.
According to the embodiment, an average value is calculated according to the contact parameters of the crimping type power semiconductor device, the measured pressure value of the crimping type power semiconductor device is used as a preset pressure value to be input into a stress field distribution calculation model, the contact parameter calculation average value of each sub-module in the crimping type power semiconductor device is obtained, the height of each sub-module in the crimping type power semiconductor device is obtained, the stress distribution of the crimping type power semiconductor device is obtained, the reconstruction of the stress field in the device is realized, and the internal electrothermal characteristic distribution is accurately calculated.
Alternatively, the stress field distribution calculation model may calculate stress distribution of the crimping type power semiconductor device, and may also calculate a contact parameter calculation average value of the crimping type power semiconductor device, specifically, step S104 is followed by step S105: the stress field distribution calculation model comprises a first sub-model and a second sub-model, wherein the first sub-model is used for calculating and obtaining the stress distribution of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of the crimping type power semiconductor device;
the second sub-model is used for calculating and obtaining a contact parameter calculation average value of the crimping type power semiconductor device according to stress distribution of the crimping type power semiconductor device;
correspondingly, after the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet the preset constraint condition and obtain the corresponding preset height value, the stress field reconstruction method of the crimping type power semiconductor device further comprises the following steps:
and obtaining the stress distribution of the crimping type power semiconductor device by using the updated first sub-model according to the measured pressure value of the crimping type power semiconductor device.
In the embodiment, when the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device do not meet the preset constraint condition, the numerical value of the preset height value in the stress field distribution calculation model is adjusted by using a preset optimizing algorithm, so that the first sub-model is updated; and the updated first sub-model obtains the stress distribution of the crimping type power semiconductor device according to the measured pressure value and the adjusted preset height value of the crimping type power semiconductor device.
According to the preset height value of each sub-module of the crimping type power semiconductor device and the measured pressure value of the crimping type power semiconductor device, accurate modeling of actual stress field distribution of the crimping type power semiconductor device can be achieved, and the device internal stress field reconstruction is achieved by considering the height of a device component.
Optionally, the parameter type of the constraint condition is not limited, and may be reasonably selected according to practical application requirements, for example, the contact parameter calculation average value may be used to represent the contact pressure calculation average value or the contact force calculation average value;
the contact parameter measurement average may be used to characterize the contact pressure measurement average or the contact force measurement average.
Optionally, when the contact parameter measurement average value is used to characterize the contact pressure measurement average value, in order to obtain the contact parameter measurement average value of the crimping-type power semiconductor device, step S102 further includes:
step S102a, placing pressure test paper in the pressure-welding type power semiconductor device, and applying pressure with the magnitude of the measured pressure value to the pressure-welding type power semiconductor device;
step S102b, after stopping applying pressure to the crimping type power semiconductor device, performing image acquisition on the pressure test paper, and obtaining an image corresponding to the pressure test paper;
step S102c, according to the image corresponding to the pressure test paper, the contact pressure measurement average value of each sub-module in the crimping type power semiconductor device is obtained by utilizing a preset functional relation.
Further, in step S102c, according to the image corresponding to the pressure test paper, using a preset functional relationship to obtain a measurement average value of the contact pressure of each sub-module in the crimping power semiconductor device includes:
step S102d, partitioning the image according to each sub-module of the crimping type power semiconductor device;
step S102e, carrying out gray scale treatment on the partitioned image to obtain the gray average value of each sub-module of the crimping type power semiconductor device;
step S102f, obtaining the average color density of each sub-module of the crimping type power semiconductor device according to the gray average value of each sub-module of the crimping type power semiconductor device and the functional relation between the color density and the gray value;
step S102g, obtaining a contact parameter measurement average value of the crimping type power semiconductor device according to the average color density of each sub-module of the crimping type power semiconductor device and the functional relation between the pressure intensity and the color density.
Further, in step S102, in order to obtain the average color density and the average contact parameter measurement value of each sub-module of the crimping power semiconductor device, the functional relationship between the color density and the gray value is obtained by curve fitting;
the functional relationship of pressure and color density can be obtained by curve fitting the relationship of pressure and color density.
In the embodiment, a pressure test paper is placed in the pressure-bonding type power semiconductor device, and a pressure with a magnitude equal to a measured pressure value is applied to the pressure-bonding type power semiconductor device through a clamp or a press;
after stopping applying pressure to the crimping type power semiconductor device, performing image acquisition on the pressure test paper, and obtaining an image corresponding to the pressure test paper;
carrying out graying treatment on the image corresponding to the pressure test paper, further obtaining the gray value of each pixel point of the pressure test paper, and fitting the color density and the gray value of the standard color card according to the data provided by the pressure test paper manual to obtain the functional relation between the color density and the gray value;
converting the gray value of each pixel point into a color density distribution result according to the gray value of each pixel point and the functional relation between the color density and the gray value;
then according to the pressure test paper data manual, a relation curve of the pressure intensity and the color density of the standard color card can be obtained, and a functional relation of the pressure intensity and the color density can be obtained through data fitting;
partitioning the image according to each sub-module of the crimping type power semiconductor device, counting to obtain the gray average value of each sub-module of the crimping type power semiconductor device, obtaining the average color density of each sub-module of the crimping type power semiconductor device according to the functional relation between the color density and the gray value, and obtaining the contact parameter measurement average value of the crimping type power semiconductor device according to the functional relation between the pressure intensity and the color density. The average value of the contact parameter measurement can be obtained by other mechanical sensors, and the measurement method can be selected according to actual conditions.
Alternatively, the constraint condition may be set according to the actual situation, for example, in step S104, the preset constraint condition may include: the relative error between the calculated average value of the contact parameters and the measured average value of the contact parameters of each sub-module in the crimping type power semiconductor device is less than 10 percent.
Further, in step S104, the preset constraint condition may further include: and (3) calculating the average value of the contact parameters of all the sub-modules in the crimping type power semiconductor device and determining whether the square difference of the average value of the contact parameters is the minimum value.
Optionally, in step S103, when the contact parameter measurement average value is used to characterize the contact force measurement average value, applying a pressure having a magnitude equal to the measurement pressure value to the crimping-type power semiconductor device, and obtaining the contact parameter measurement average value of the crimping-type power semiconductor device includes:
the average value of the contact force measurement is measured by a mechanical sensor.
Furthermore, in order to achieve the above object, the present invention also provides a stress field reconstruction system for a compression power semiconductor device, and fig. 2 is a schematic diagram of a stress field reconstruction system for a compression power semiconductor device according to the present invention, as shown in fig. 2, where the stress field reconstruction system for a compression power semiconductor device according to the present invention includes:
the model construction module is used for constructing a stress field distribution calculation model, wherein the stress field distribution calculation model is used for calculating and obtaining a contact parameter calculation average value of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of each sub-module in the crimping type power semiconductor device;
the contact parameter measurement average value acquisition module is used for applying pressure with the size of a measurement pressure value to the crimping type power semiconductor device to obtain the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device;
the contact parameter calculation average value acquisition module is used for inputting a measured pressure value of the crimping type power semiconductor device into the stress field distribution calculation model as a preset pressure value to obtain a contact parameter calculation average value of each sub-module in the crimping type power semiconductor device;
the preset height value acquisition module is used for adjusting the numerical value of the preset height value in the stress field distribution calculation model by utilizing a preset optimizing algorithm when the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device do not meet the preset constraint condition, until the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet the preset constraint condition, and obtaining the corresponding preset height value.
In this embodiment, a crimping type semiconductor device that can be used for a crimping type power semiconductor device stress field reconstruction system includes: a power semiconductor device including a contact surface is commonly used for a crimping type IGBT device, a crimping type SiC device, a thyristor device, and the like.
The realization process of the stress field reconstruction system of the crimping type power semiconductor device comprises the following steps:
establishing a stress field distribution calculation model by using finite element simulation software, wherein the stress field distribution calculation model is used for calculating stress field distribution of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of each sub-module in the crimping type power semiconductor device, and calculating a contact parameter calculation average value of the crimping type power semiconductor device according to the stress field distribution of the crimping type power semiconductor device; the preset pressure value applied to the crimping type power semiconductor device can also be used for measuring a contact parameter measurement average value, for example, the contact pressure measurement average value is measured by using a pressure test paper or a pressure sensor according to the preset pressure value applied to the crimping type power semiconductor device.
And applying pressure with the magnitude of the measured pressure value to the crimping type power semiconductor device to obtain the average value of the contact parameter measurement of each sub-module in the crimping type power semiconductor device.
The stress field distribution calculation model comprises a first sub-model and a second sub-model, wherein the first sub-model is used for calculating and obtaining the internal stress field distribution of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of each sub-module in the crimping type power semiconductor device; the preset height value can be a group of same values or a group of different values;
the second sub-model is used for obtaining the calculation average value of the sub-module contact pressure inside the crimping type power semiconductor device according to the internal stress field distribution of the crimping type power semiconductor device, for example, obtaining the calculation average value of the sub-module contact pressure inside the crimping type power semiconductor device according to the internal stress field distribution of the crimping type power semiconductor device;
when the contact pressure calculation average value and the contact pressure measurement average value of each sub-module in the compression-type power semiconductor device do not meet the preset constraint condition, the numerical value of the preset height value in the stress field distribution calculation model is adjusted by utilizing a preset optimizing algorithm until the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the compression-type power semiconductor device meet the preset constraint condition, and the corresponding preset height value is obtained.
The contact parameter calculation average value and the contact parameter measurement average value can be selected according to actual requirements, wherein the parameters can be pressure, contact force or other parameters. When the contact parameter measurement average value is the contact force pressure measurement average value, the contact force pressure measurement average value can be obtained through a pressure test paper or a mechanical sensor, and the specific method can be selected according to actual requirements.
Alternatively, the constraint condition may be set according to the actual situation, for example, a relative error between a contact pressure calculation average value and a contact pressure measurement average value of each sub-module inside the crimping type power semiconductor device is less than 10%, and whether a difference square between the contact pressure calculation average value and the contact pressure measurement average value of each sub-module inside the crimping type power semiconductor device is a minimum value;
the optimization algorithm may be cobyloa, gradient optimization, particle swarm optimization, neural network, or other algorithms. Optionally, the stress field distribution calculation model includes a first sub-model and a second sub-model, wherein the first sub-model is used for calculating and obtaining stress distribution of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of the crimping type power semiconductor device;
the second sub-model is used for calculating and obtaining a contact parameter calculation average value of the crimping type power semiconductor device according to stress distribution of the crimping type power semiconductor device;
correspondingly, after the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet the preset constraint condition and obtain the corresponding preset height value, the stress field reconstruction method of the crimping type power semiconductor device further comprises the following steps:
and obtaining the stress distribution of the crimping type power semiconductor device by using the updated first sub-model according to the measured pressure value of the crimping type power semiconductor device.
In this embodiment, according to the preset height value of each sub-module of the compression-type power semiconductor device and the measured pressure value of the compression-type power semiconductor device, accurate modeling of actual stress field distribution of the compression-type power semiconductor device can be achieved, so that the height of a device component is considered, and reconstruction of the internal stress field of the device is achieved.
Optionally, the contact parameter calculation average value is used for characterizing the contact pressure calculation average value or the contact force calculation average value;
the contact parameter measurement average is used to characterize the contact pressure measurement average or the contact force measurement average.
Optionally, when the contact parameter measurement average value is used to characterize the contact pressure measurement average value, in order to obtain the contact parameter measurement average value of the crimping-type power semiconductor device, step S102 further includes:
placing pressure test paper in the pressure-welding type power semiconductor device, and applying pressure with the magnitude of a measured pressure value to the pressure-welding type power semiconductor device;
after stopping applying pressure to the crimping type power semiconductor device, performing image acquisition on the pressure test paper, and obtaining an image corresponding to the pressure test paper;
and according to the image corresponding to the pressure test paper, obtaining the average value of the contact pressure measurement of each sub-module in the crimping type power semiconductor device by utilizing a preset functional relation.
Further, according to the image corresponding to the pressure test paper, the obtaining the average value of the contact pressure measurement of each sub-module in the crimping power semiconductor device by using the preset functional relation comprises the following steps:
partitioning the image according to each sub-module of the crimping type power semiconductor device;
carrying out graying treatment on the partitioned image to obtain a gray average value of each sub-module of the crimping type power semiconductor device;
obtaining the average color density of each sub-module of the crimping type power semiconductor device according to the gray average value of each sub-module of the crimping type power semiconductor device and the functional relation between the color density and the gray value;
and obtaining a contact parameter measurement average value of the crimping type power semiconductor device according to the average color density of each sub-module of the crimping type power semiconductor device and the functional relation between the pressure intensity and the color density.
Further, the functional relation between the color density and the gray value is obtained by curve fitting the relation between the color density and the gray value;
the functional relationship of the intensity of pressure and the color density is obtained by curve fitting the relationship of the intensity of pressure and the color density.
In the embodiment, a pressure test paper is placed in the pressure-bonding type power semiconductor device, and a pressure with a magnitude equal to a measured pressure value is applied to the pressure-bonding type power semiconductor device through a clamp or a press;
after stopping applying pressure to the crimping type power semiconductor device, performing image acquisition on the pressure test paper, and obtaining an image corresponding to the pressure test paper;
carrying out graying treatment on the image corresponding to the pressure test paper, further obtaining the gray value of each pixel point of the pressure test paper, and fitting the color density and the gray value of the standard color card according to the data provided by the pressure test paper manual to obtain the functional relation between the color density and the gray value;
converting the gray value of each pixel point into a color density distribution result according to the gray value of each pixel point and the functional relation between the color density and the gray value;
then according to the pressure test paper data manual, a relation curve of the pressure intensity and the color density of the standard color card can be obtained, and a functional relation of the pressure intensity and the color density can be obtained through data fitting;
partitioning the image according to each sub-module of the crimping type power semiconductor device, counting to obtain the gray average value of each sub-module of the crimping type power semiconductor device, obtaining the average color density of each sub-module of the crimping type power semiconductor device according to the functional relation between the color density and the gray value, and obtaining the contact parameter measurement average value of the crimping type power semiconductor device according to the functional relation between the pressure intensity and the color density. The average value of the contact parameter measurement can be obtained by other mechanical sensors, and the measurement method can be selected according to actual conditions.
Optionally, the preset constraint condition includes: the relative error between the calculated average value of the contact parameters and the measured average value of the contact parameters of each sub-module in the crimping type power semiconductor device is less than 10 percent.
Further, the preset constraint condition further includes: and (3) calculating the average value of the contact parameters of all the sub-modules in the crimping type power semiconductor device and determining whether the square difference of the average value of the contact parameters is the minimum value.
Optionally, when the contact parameter measurement average value is used to characterize the contact force measurement average value, applying a pressure having a magnitude of a measurement pressure value to the crimping-type power semiconductor device, obtaining the contact parameter measurement average value of the crimping-type power semiconductor device includes:
the average value of the contact force measurement is measured by a mechanical sensor.
The invention has the beneficial effects that: (1) The method can consider the height of the device component, realize the accurate modeling of the actual stress field distribution of the crimping type power semiconductor device, and accurately calculate the internal electric heating characteristic distribution;
(2) The invention can also output the height distribution of each sub-module in the device, and provide guidance for the packaging optimization design of the device.
Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention. It will be clearly understood by those skilled in the art that, for convenience and brevity of description, specific working procedures of the apparatus and device described above may refer to corresponding procedures in the foregoing method embodiments, which are not described herein again.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the device embodiments described above are merely illustrative.
It will be appreciated by persons skilled in the art that the scope of the invention referred to in the present invention is not limited to the specific combinations of the technical features described above, but also covers other technical features formed by any combination of the technical features described above or their equivalents without departing from the inventive concept. Such as the above-mentioned features and the technical features disclosed in the present invention (but not limited to) having similar functions are replaced with each other.
It should be understood that, the sequence numbers of the steps in the summary and the embodiments of the present invention do not necessarily mean the order of execution, and the execution order of the processes should be determined by the functions and the internal logic, and should not be construed as limiting the implementation process of the embodiments of the present invention.
Claims (10)
1. A method for reconstructing stress field of a crimping type power semiconductor device, the method comprising:
constructing a stress field distribution calculation model, wherein the stress field distribution calculation model is used for calculating and obtaining a contact parameter calculation average value of a compression-joint type power semiconductor device according to a preset pressure value applied to the compression-joint type power semiconductor device and a preset height value of each sub-module in the compression-joint type power semiconductor device;
applying pressure with the magnitude of the measured pressure value to the crimping type power semiconductor device to obtain a contact parameter measurement average value of each sub-module in the crimping type power semiconductor device;
inputting the measured pressure value of the crimping type power semiconductor device into the stress field distribution calculation model as a preset pressure value to obtain the contact parameter calculation average value of each sub-module in the crimping type power semiconductor device;
when the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device do not meet a preset constraint condition, the numerical value of a preset height value in the stress field distribution calculation model is adjusted by utilizing a preset optimizing algorithm until the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet the preset constraint condition, and a corresponding preset height value is obtained.
2. The stress field reconstruction method of a crimping type power semiconductor device according to claim 1, wherein the stress field distribution calculation model comprises a first sub-model and a second sub-model, wherein the first sub-model is used for calculating and obtaining the stress distribution of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of the crimping type power semiconductor device;
the second sub-model is used for calculating and obtaining a contact parameter calculation average value of the crimping type power semiconductor device according to stress distribution of the crimping type power semiconductor device;
correspondingly, after the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet a preset constraint condition and obtain a corresponding preset height value, the method further comprises:
and according to the measured pressure value of the crimping type power semiconductor device, obtaining the stress distribution of the crimping type power semiconductor device by using the updated first sub-model.
3. The compression-joint type power semiconductor device stress field reconstruction method according to claim 1, wherein the contact parameter calculation average value is used for representing a contact pressure calculation average value or a contact force calculation average value;
the contact parameter measurement average is used to characterize a contact pressure measurement average or a contact force measurement average.
4. The method for reconstructing stress field of a power semiconductor device according to claim 1, wherein when the contact parameter measurement average value is used for characterizing a contact pressure measurement average value, the applying a pressure having a magnitude equal to the measured pressure value to the power semiconductor device, and obtaining the contact parameter measurement average value of the power semiconductor device comprises:
placing pressure test paper in the pressure-welding type power semiconductor device, and applying pressure with the magnitude of the measured pressure value to the pressure-welding type power semiconductor device;
after stopping applying pressure to the crimping type power semiconductor device, performing image acquisition on the pressure test paper, and obtaining an image corresponding to the pressure test paper;
and according to the image corresponding to the pressure test paper, obtaining a contact pressure measurement average value of each sub-module in the crimping type power semiconductor device by utilizing a preset functional relation.
5. The method for reconstructing stress field of a crimping power semiconductor device according to claim 4, wherein obtaining a contact parameter measurement average value of the crimping power semiconductor device according to the image corresponding to the pressure test paper by using a preset functional relation comprises:
partitioning the image according to each sub-module of the crimping type power semiconductor device;
carrying out graying treatment on the partitioned image to obtain a gray average value of each sub-module of the crimping type power semiconductor device;
obtaining the average color density of each sub-module of the crimping type power semiconductor device according to the gray average value of each sub-module of the crimping type power semiconductor device and the functional relation between the color density and the gray value;
and obtaining the contact parameter measurement average value of the crimping type power semiconductor device according to the average color density of each sub-module of the crimping type power semiconductor device and the functional relation between the pressure intensity and the color density.
6. The method for reconstructing stress field of crimping type power semiconductor device according to claim 5, wherein the functional relation between color density and gray value is obtained by curve fitting the relation between color density and gray value;
the functional relationship of the intensity of pressure and the color density is obtained by curve fitting the relationship of the intensity of pressure and the color density.
7. The method for reconstructing stress field of crimping type power semiconductor device according to claim 1, wherein the preset constraint condition comprises: and the relative error between the calculated average value of the contact parameters and the measured average value of the contact parameters of each sub-module in the crimping type power semiconductor device is less than 10%.
8. The method for reconstructing stress field of crimping type power semiconductor device as set forth in claim 7, wherein said preset constraint condition further comprises: and calculating the average value of the contact parameters of each sub-module in the crimping type power semiconductor device and judging whether the square difference of the average value of the contact parameter measurement is the minimum value or not.
9. The method for reconstructing stress field of a power semiconductor device according to claim 1, wherein when the average value of contact parameter measurement is used for representing the average value of contact force measurement, the step of applying a pressure having a magnitude equal to a measured pressure value to the power semiconductor device to obtain the average value of contact parameter measurement of the power semiconductor device includes:
the contact force measurement average value is measured by a mechanical sensor.
10. A crimping power semiconductor device stress field reconstruction system, the system comprising:
the model construction module is used for constructing a stress field distribution calculation model, wherein the stress field distribution calculation model is used for calculating and obtaining a contact parameter calculation average value of the crimping type power semiconductor device according to a preset pressure value applied to the crimping type power semiconductor device and a preset height value of each sub-module in the crimping type power semiconductor device;
the contact parameter measurement average value acquisition module is used for applying pressure with the size of a measurement pressure value to the crimping type power semiconductor device to obtain the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device;
the contact parameter calculation average value obtaining module is used for inputting the measured pressure value of the crimping type power semiconductor device into the stress field distribution calculation model as a preset pressure value to obtain the contact parameter calculation average value of each sub-module in the crimping type power semiconductor device;
and the preset height value acquisition module is used for adjusting the numerical value of the preset height value in the stress field distribution calculation model by utilizing a preset optimizing algorithm when the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device do not meet the preset constraint condition until the contact parameter calculation average value and the contact parameter measurement average value of each sub-module in the crimping type power semiconductor device meet the preset constraint condition, and obtaining the corresponding preset height value.
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