Device for preventing failure of power semiconductor devices

Abstract

To provide a failure prevention device for a power semiconductor element that prompts a user to replace a part before the power semiconductor element breaks down. [Solution] A failure prevention device for a power semiconductor element that is mounted by soldering to an insulating substrate and cooled by cooling water, the failure prevention device has water temperature measurement means S1, S2 that measure the temperature of the cooling water, element temperature measurement means S3 that measures the temperature of the power semiconductor element, calculation means S5 that calculates the remaining life of the solder from the temperature fluctuation range of the power semiconductor element and the temperature fluctuation range of the cooling water, and notification means S7 that notifies the user that the power semiconductor element needs to be replaced if the remaining life of the solder calculated by the calculation means is less than a threshold value (YES) (S6).

Description

[Technical Field]

[0001] The present disclosure relates to a device for preventing failure of a power semiconductor device. [Background technology]

[0002] A conventional failure prevention device is disclosed, for example, in Patent Document 1 below. Patent Document 1 discloses a semiconductor device that uses a thermal diode to monitor the temperature of an element and identifies the degree of solder deterioration from the temperature fluctuation range of the element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-056333 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional semiconductor device, the stress on the solder is calculated using only the temperature sensor of the element, so when the power of the semiconductor device is turned off, it is not possible to check the temperature fluctuations of the element, and there is a concern that the stress on the solder may be misjudged. [Means for solving the problem]

[0005] In order to solve the above problem, one embodiment of a failure prevention device for power semiconductor elements is a failure prevention device for power semiconductor elements that are mounted by soldering to an insulating substrate and cooled by cooling water, and the failure prevention device has a water temperature measurement means for measuring the temperature of the cooling water, an element temperature measurement means for measuring the temperature of the power semiconductor element, a calculation means for calculating the remaining life of the solder from the temperature fluctuation range of the power semiconductor element and the temperature fluctuation range of the cooling water, and a notification means for notifying the user to replace the power semiconductor element if the remaining life of the solder calculated by the calculation means is less than a threshold value. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a power semiconductor element failure prevention device that can prompt a user to replace a part before the power semiconductor element fails. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of a series of operations executed by a power semiconductor device failure prevention device according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0008] (Device for preventing failure of power semiconductor devices) The failure prevention device for power semiconductor elements of the present invention is a failure prevention device for power semiconductor elements that are mounted by soldering to an insulating substrate and cooled by cooling water, and the failure prevention device has a water temperature measurement means for measuring the temperature of the cooling water, an element temperature measurement means for measuring the temperature of the power semiconductor element, a calculation means for calculating the remaining life of the solder from the temperature fluctuation range of the power semiconductor element and the temperature fluctuation range of the cooling water, and a notification means for notifying the user to replace the power semiconductor element if the remaining life of the solder calculated by the calculation means is less than a threshold value, and may have other means as necessary.

[0009] The power semiconductor device may include other members as necessary.

[0010] Conventionally, when a thermal cycle is repeatedly applied to the solder due to the start / stop of a semiconductor element or temperature fluctuations in the cooling water, cracks may occur in the solder due to the difference in the linear expansion coefficient between the semiconductor element and the substrate, and these cracks may deteriorate heat dissipation, causing an overheating abnormality (diagnosis occurrence) and leading to a risk of failure. The power semiconductor element failure prevention device of the present invention can prompt the user to replace the part before the power semiconductor element fails, thereby reducing the risk of failure.

[0011] The power semiconductor device failure prevention device of the present invention will now be described in detail with reference to Fig. 1. Fig. 1 is a diagram showing an example of a series of operations executed by the power semiconductor device failure prevention device of the present invention.

[0012] In step 1 (S1), the failure prevention device measures the temperature of the cooling water that cools the power semiconductor elements using a water temperature measurement means, and acquires the temperature fluctuation range of the cooling water. There are no particular restrictions on the water temperature measurement means, and as long as it can detect fluctuations in the temperature of the cooling water, it can be appropriately selected depending on the purpose, and examples include a temperature sensor.

[0013] The range of fluctuation in the temperature of the cooling water obtained by the water temperature measuring means is accumulated as big data (step 2: S2).

[0014] Next, in step 3 (S3), the failure prevention device measures the temperature of the power semiconductor element using element temperature measurement means and acquires the temperature fluctuation range of the power semiconductor element. The element temperature measurement means is not particularly limited and can be appropriately selected depending on the purpose as long as it can detect temperature fluctuations due to self-heating of the power semiconductor element, and examples include temperature sensors.

[0015] The temperature fluctuation range of the power semiconductor element obtained by the element temperature measuring means is accumulated as big data (step 4: S4).

[0016] Next, the remaining life of the solder is calculated by the calculation means from the temperature fluctuation range of the cooling water obtained by the water temperature measurement means and the temperature fluctuation range of the power semiconductor element obtained by the element temperature measurement means (step 5: S5). The remaining life of the solder can be calculated using the following Coffin-Manson law.

[0017]

number

[0018] In the formula, the details of each symbol are as follows:

[0019] N1: Market stress N2: Number of cycles during solder joint test ΔT1: Temperature fluctuation range of cooling water + temperature fluctuation range of power semiconductor devices ΔT2: Environmental temperature range during solder joint test (for example, if the test was conducted between -40°C and 105°C, enter 145°C) k: Boltzmann constant Ea: Activation energy T 1max :Highest temperature on the market T 2max : Maximum temperature during solder joint test

[0020] For example, after inputting the temperature fluctuation range of the cooling water and the temperature fluctuation range of the power semiconductor element into ΔT1 to calculate N1, the sum of N1 during each temperature fluctuation is compared with the number of cycles at which 100% cracking occurs. At this time, it is confirmed whether the difference between the remaining life (number of cycles) of the solder and the number of cycles at which 100% cracking occurs is less than a threshold value (step 6: S6). If the difference between the remaining life (number of cycles) of the solder and the number of cycles at which 100% cracking occurs is less than the threshold value, a warning is issued by the notification means to notify the user and urge them to replace the power semiconductor element (step 7: S7). If the difference between the remaining life (number of cycles) of the solder and the number of cycles at which 100% cracking occurs is not less than the threshold value, the process may return to step 5 (S5) without proceeding to step 7.

[0021] The threshold value is not particularly limited and can be appropriately selected depending on the purpose, and can be set to, for example, 100 cycles.

[0022] The fault detection device may also have, as other means, a memory or the like for storing values ​​of the temperature fluctuation range of the cooling water and the temperature fluctuation range of the power semiconductor elements.

[0023] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Claims

[Claim 1] A failure prevention device for a power semiconductor element that is mounted by soldering to an insulating substrate and cooled by cooling water, comprising: The failure prevention device is a water temperature measuring means for measuring the temperature of the cooling water; an element temperature measuring means for measuring the temperature of the power semiconductor element; a calculation means for calculating a remaining life of the solder from the temperature fluctuation range of the power semiconductor element and the temperature fluctuation range of the cooling water; a notification means for notifying a user to replace the power semiconductor element when the remaining life of the solder calculated by the calculation means is less than a threshold value; 1. A power semiconductor device failure prevention device comprising:

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