JP2005127729A - Reliability testing device and reliability test method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliability testing device and a reliability test method capable of performing a reliability test in a comparatively short time at low cost, and having a small error of an estimated value based on the test result. <P>SOLUTION: This device has ten fixing parts 2 where test elements are fixed, having terminals to be connected to the test elements, and connection parts 3 for connecting the fixing parts 2 to a cassette 1, on the temperature-adjustable cassette 1 provided with a heating element. Heating resistors are arranged increasingly successively from zero to the number of nine respectively on the ten fixing parts 2. Driving powers having mutually the same value are supplied to each test element from a control part, and the cassette 1 is controlled at a prescribed temperature. Temperatures at the test time of the test elements fixed to the fixing parts 2 are raised successively corresponding to the number of the resistors on the fixing parts 2. Since tests in a plurality of temperature conditions are performed simultaneously, a required time for the reliability test is shortened compared with hitherto. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a reliability test apparatus and a reliability test method for, for example, an electric element and an optical element, and more particularly to reliability of an element that is energized and has a high temperature, such as an electric element such as a semiconductor power transistor and an optical element such as a laser. The present invention relates to a reliability test apparatus and a reliability test apparatus.

  In recent years, in the field of semiconductor elements, higher density and integration of elements have been promoted, and in particular, miniaturization of semiconductor elements mounted on such equipment in accordance with miniaturization and weight reduction of mobile communication equipment and the like. Is moving forward. In order to improve the electrical characteristics and optical characteristics of the semiconductor element, and to increase the mean life to failure (MTTF) of the semiconductor element, the amount of heat generated by the semiconductor element itself was suppressed and generated. It is important to efficiently release heat from the element. Such characteristics relating to heat of the semiconductor element require evaluation in a packaged state in evaluation of thermal resistance of the manufactured element, evaluation of average life by a high temperature acceleration test, and the like.

  In general, the average life h of a packaged semiconductor element has a relationship represented by the following equation (1) with the activation energy E and the junction temperature Tj of the element.

h = Aexp (E / kTj) (1)
Here, A is a constant related to the test current density and the like, and k is a Boltzmann constant.

  The junction temperature Tj is obtained by the following equation (2).

Tj = T + Rth · P (2)
Here, Rth is the thermal resistance value, and P is the power when the element is energized.

  As shown in the above equation (2), the junction temperature Tj is the sum of the environmental temperature T at which the test is performed and the temperature rise Rth · P due to heat generation of the element.

  In the conventional reliability test method, a plurality of elements are energized under the same environmental temperature T, and the test is performed under the same junction temperature Tj. The elapsed time from the start of the test to the time when the electrical or optical characteristics of each element deteriorates is the lifetime at the junction temperature Tj of the element. A value obtained by adding and averaging the lifetimes of the plurality of elements is the average lifetime at the junction temperature Tj. In the conventional reliability test method, a plurality of types of junction temperatures Tj that are sufficiently higher than room temperature are set, and the average lifetime of a plurality of elements when testing is performed for each of the plurality of junction temperatures Tj. The average lifetime of the element is estimated.

  FIG. 3A is a schematic plan view showing a reliability test apparatus used in a conventional reliability test method, and FIG. 3B is a schematic cross-sectional view taken along line B-B ′ of FIG. 3A. This reliability test apparatus includes a cassette 11 provided with a heating element, and ten fixing portions 12 provided on the upper surface of the cassette 11 for fixing the device under test and supplying power to the device under test. And a connecting portion 13 for connecting the fixing portion 12 to the cassette 11. The heating element of the cassette 11 is controlled to have a predetermined temperature by a control unit (not shown) connected via a connection terminal 14 provided on the back surface of the cassette 11. Thus, the ambient temperature of the device under test is controlled by bringing the entire cassette 11 to a predetermined temperature. A predetermined drive power is supplied to the device under test from the control unit (not shown) connected to the connection terminal 14 via the connection unit 13 and the fixing unit 12.

  FIG. 4 is a diagram for specifically explaining an example in which the average lifetime of the element at room temperature is obtained by a conventional reliability test method. The horizontal axis of the coordinates shown in FIG. 4 is the reciprocal 1 / T of the absolute temperature T (K: Kelvin), and the vertical axis is the logarithm of the average life MTTF (time). The reliability test was performed using 30 GaAs (gallium arsenide) HBT (heterojunction bipolar transistor) power amplification elements having a thermal resistance Rth of about 50 ° C./W. The 30 HBT power amplifying elements are divided into three groups of 10 HBT power amplifying elements, and the environmental temperature of each group is set to 80 ° C., 120 ° C. and 160 ° C. Three tests are performed. When the energization condition to the HBT power amplifying element is that the voltage V is 3.3 V, the current I is 0.6 A, and the power P = IV is about 2 W (Watt), each element has a thermal resistance Heat of the value obtained by multiplying Rth by power P is generated. Since the fixed portions 12 of the cassette 11 of the reliability test apparatus have substantially the same thermal resistance, all the HBT power amplifying elements respectively disposed in the plurality of fixed portions 12 have a temperature of 100 ° C. which is substantially equal to the generated heat. Temperature rise occurs. Therefore, the junction temperature Tj is 453 K (180 ° C.), 493 K (220 ° C.), and 533 K (260 ° C.) in three tests with different environmental temperatures. In the horizontal axis of FIG. 4, t11 (T = 260 ° C.), t12 (T = 220 ° C.), and t13 (T = 180 ° C.) are points according to each junction temperature. At these three junction temperatures Tj, the average life of each of the ten elements was 500 hours (h11), 1200 hours (h12), and 2500 hours (h13). In the coordinates of FIG. 4, the activation energy is about 1.4 eV from the slope of the straight line L11 connecting the three points determined by the average lifetime for each junction temperature. With this activation energy, the average lifetime MTTF at room temperature is estimated to be about 100,000 hours.

  However, in the conventional reliability test method, when a test is performed with one reliability test apparatus, it is necessary to set a plurality of the environmental temperatures and perform the test until all the elements deteriorate at each environmental temperature. In the reliability test shown in FIG. 4, since one test is performed three times in accordance with three types of environmental temperatures, the time required for all tests is at least the average life of each test. A certain 500 hours (h11), 1200 hours (h12), and 2500 hours (h13) are added to 4200 hours or more. In other words, more than half a year is required for the reliability test. The time required for this reliability test is longer when the variation of the characteristics of the device under test is large, because the time required for setting each test condition, temperature increase and decrease, etc. becomes longer. That is, the conventional reliability test has a problem that a relatively long time is required.

  Therefore, when tests of each environmental temperature are performed simultaneously using three reliability test apparatuses, the time required for the entire reliability test is the test at the environmental temperature at which the test time is the longest, and the junction temperature Tj Can be shortened to about 2500 hours, which is the average life when 180 ° C. However, since three reliability test apparatuses are required, there is a problem that the cost of the reliability test increases.

In addition, the conventional reliability test method has a problem that an error in an estimated value related to the average life at room temperature is large. That is, in FIG. 4, the average lifetime hr at room temperature is estimated from the slope of the straight line L11 connecting the three points indicating the average lifetime, and the slope of the straight line L11 varies relatively depending on the value of the average lifetime. For example, the average lifetime is calculated by excluding the element having the shortest lifetime in the group having the junction temperature Tj of 260 ° C. and the element having the longest lifetime in the group having the junction temperature Tj of 180 ° C., and calculating the average lifetime. When connecting the indicated points, a straight line L12 indicated by a broken line is obtained. The average life hr ′ at room temperature Tr determined by the straight line L12 is a small value with a relatively large difference from the average life hr determined by the straight line L11 on the log scale. Thus, the conventional reliability test method has a problem that the error of the estimated value regarding the average life at room temperature is relatively large.
JP 61-128541 A

  Therefore, an object of the present invention is to provide a reliability test apparatus and a reliability test method that can perform a reliability test in a relatively short time and at a low cost, and that has a small error in an estimated value based on a test result. It is in.

In order to solve the above problems, a semiconductor device reliability test apparatus of the present invention includes:
A pedestal with adjustable temperature,
A plurality of fixing portions provided on the pedestal to which the device under test is fixed;
A plurality of heat transfer bodies each provided in the fixed portion and having different thermal resistance;
And a power supply means for supplying driving power to the device under test.

  According to the above configuration, the device under test is fixed to the plurality of fixing portions, the driving power is supplied to the device under test from the power supply means, and the pedestal is adjusted to a predetermined temperature, so that the device under test is A reliability test of the test element is performed. The device under test is supplied with the driving power and generates heat. Since the plurality of thermal resistors provided in the fixed portion have different thermal resistances, the temperatures reached by the plurality of devices under test are different from each other. Therefore, since the plurality of elements under test can be tested simultaneously under different temperatures, it is not necessary to perform the test a plurality of times at different environmental temperatures as in the prior art. As a result, the reliability test of the device under test can be performed in a relatively short time.

  In addition, since one reliability test apparatus can perform a reliability test under a plurality of temperature conditions at the same time, it is not necessary to use a plurality of reliability test apparatuses, and the reliability test can be performed at a low cost. .

  The thermal resistance is the amount of temperature rise that occurs in a product when 1 W (watt) of heat is applied to the product.

In addition, the semiconductor device reliability test apparatus according to the present invention includes:
A pedestal having a plurality of temperature control regions that can be adjusted to different temperatures;
A fixed portion provided in each of the plurality of temperature control regions of the pedestal, to which the device under test is fixed;
And power supply means for supplying drive power to the device under test.

  According to the above configuration, the plurality of elements to be tested are respectively fixed to the plurality of fixing portions, and driving power is supplied from the power supply means, and a plurality of temperature adjustments provided with the plurality of fixing portions. The region is adjusted to a different temperature, and the reliability of the device under test is tested. The plurality of devices under test generate heat when supplied with the driving power, and the temperature control regions are adjusted to different temperatures, so that the plurality of devices under test have different temperatures. Therefore, since the plurality of elements under test can be simultaneously tested under different ultimate temperatures, it is not necessary to perform the test a plurality of times by changing the environmental temperature as in the prior art. As a result, the reliability test of the device under test can be performed in a relatively short time.

  In addition, since one reliability test apparatus can perform a reliability test under a plurality of temperature conditions at the same time, it is not necessary to use a plurality of reliability test apparatuses, and the reliability test can be performed at a low cost. .

The reliability testing apparatus for a semiconductor device of one embodiment is as follows:
Temperature measuring means for measuring the temperature of the device under test;
Based on the temperature of the device under test measured by the temperature measuring means and the driving power supplied to the device under test by the power supply means, the thermal resistance of the device under test in the state of being arranged in the fixed portion And a thermal resistance detecting means for detecting.

  According to the embodiment, the temperature when the device under test is driven is detected by the temperature measuring means. Based on the temperature of the device under test and the drive power supplied to the device under test, the thermal resistance of the device under test in the state of being arranged in the fixed portion is detected by the thermal resistance detecting means. For example, by measuring the thermal resistance of the fixed part or the like in advance, the thermal resistance of only the element under test is calculated from the thermal resistance of the element under test placed in the fixed part. Thereby, variation in thermal resistance among the plurality of elements under test can be calculated. By correcting the lifetime obtained by this test based on this variation in thermal resistance, the lifetime of the device under test at room temperature can be obtained with a small error.

The reliability test method of the semiconductor element of the present invention is:
The same drive power is supplied to a plurality of devices under test, and the devices under test are simultaneously driven under different temperatures.

  According to the above configuration, the plurality of elements to be tested are simultaneously driven at different temperatures while being supplied with the same driving power. Therefore, since the reliability test under different temperature conditions can be performed at the same time, the reliability test can be performed in a shorter time than in the conventional case where the reliability test under the same temperature condition is performed a plurality of times.

A reliability test method for a semiconductor device according to an embodiment is as follows:
By connecting thermal resistors having different thermal resistances to the plurality of devices under test, the temperatures of the devices under test are made different from each other.

  According to the embodiment, the temperature condition of the device under test can be easily varied.

A reliability test method for a semiconductor device according to an embodiment is as follows:
The temperatures of the plurality of devices under test are made different from each other by making the temperatures of the environments where the devices under test are arranged different from each other.

  According to the embodiment, the temperature condition of the device under test can be easily varied.

  Here, the environment refers to any of a gas, a solid, and a liquid that is in direct or indirect contact with the device under test and transfers heat to the device under test.

  As described above, the semiconductor element reliability test apparatus according to the present invention includes a pedestal with adjustable temperature, a plurality of fixing portions provided on the pedestal to which the element under test is fixed, and each of the fixing portions. And a plurality of thermal resistors having different thermal resistances and power supply means for supplying driving power to the device under test, the temperatures reached by the plurality of devices under test can be made different from each other. Thereby, a plurality of devices under test can be tested simultaneously under different temperature conditions. Therefore, the reliability test of the device under test can be performed in a relatively short time. In addition, since it is not necessary to use a plurality of reliability test apparatuses at the same time, the reliability test can be performed at a low cost.

  The semiconductor element reliability testing apparatus of the present invention is provided with a pedestal having a plurality of temperature control regions that can be adjusted to different temperatures, and a plurality of temperature control regions of the pedestal, and the device under test is fixed. A plurality of devices under test can be simultaneously tested under different temperature conditions, so that a reliability test can be performed. This can be done in a relatively short time. In addition, since it is not necessary to use a plurality of reliability test apparatuses at the same time, the reliability test can be performed at a low cost.

  In the semiconductor element reliability testing method of the present invention, a plurality of devices under test are driven at the same time by supplying the same drive power to each other while different temperatures reached by each device under test are different. The test can be performed simultaneously under the conditions, and the reliability test can be performed in a shorter time than conventional.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
(First embodiment)
FIG. 1A is a schematic plan view showing a semiconductor device reliability test apparatus according to a first embodiment of the present invention. 1B is a schematic cross-sectional view taken along line AA ′ of FIG. 1A.

  Using the reliability test apparatus of the present embodiment, a reliability test of a GaAs HBT power amplifying element having a thermal resistance Rth of 50 ° C./W was performed. From this test result, the average life MTTF of the HBT power amplifying element at room temperature was calculated. Ask.

  The reliability test apparatus includes a cassette 1 as a pedestal provided with a heating element, and 10 pieces provided on the upper surface of the cassette 1 and having a terminal to which the element under test is fixed and connected to the element under test. And a connecting portion 3 for connecting the fixing portion 2 to the cassette 1. The heating element of the cassette 1 is controlled to have a predetermined temperature by a control unit (not shown) connected via a connection terminal 4 provided on the back surface of the cassette 1. Thereby, the temperature of the entire cassette 1 is controlled to control the environmental temperature of the device under test. A control unit (not shown) connected to the connection terminal 4 supplies substantially the same drive power to the plurality of devices under test via the connection unit 3 and the fixing unit 2. .

  The fixing portion 2 is provided with a thermal resistor whose thermal resistance is known in advance. As the thermal resistor, a heat resistant film to which a silver paste of a conductive adhesive layer is attached is used, and this resistor has a thermal resistance of 5 ° C./W. This resistor is arranged in each fixed part 2 in a different number. As a result, the amount of heat transferred from the element under test fixed to the fixing part 2 to the cassette 1 changes, and the temperature of the element under test can be changed for each fixing part 2. Specifically, a thermal resistor is not disposed in the first fixing portion 2, and two to nine resistors are sequentially disposed from the second fixing portion 2 to the tenth fixing portion 2. ing.

  When the ten devices under test fixed to the fixing portion 2 are energized under the conditions of a cassette temperature (environment temperature) of 80 ° C., a drive voltage of 3.3 V, and a drive current of 0.6 A, each device under test Reach different junction temperatures Tj. The junction temperature Tj is a temperature corresponding to the number of thermal resistances provided in the fixed portion 2. That is, the first device under test fixed to the first fixing portion 2 where no thermal resistor is arranged has a junction temperature Tj of 180 ° C., and the tenth fixing portion where nine thermal resistors are arranged. The tenth device under test fixed to 2 has a junction temperature Tj of 270 ° C. The temperature of each device under test from the first device under test to the tenth device under test is a value that increases linearly between the above 180 ° C. and 270 ° C.

  As a result of performing a reliability test under the above temperature conditions, the life of the device under test having a junction temperature of 180 ° C. (corresponding to t10 on the horizontal axis) was the longest, about 2500 hours (h10). On the other hand, the life of the device under test having a junction temperature of 260 ° C. (corresponding to t1 on the horizontal axis) was the shortest, about 500 hours (h1).

  Based on the lifetime values of the first to tenth devices under test, a straight line L1 is drawn by the least square method at the coordinates shown in FIG. 2, and the activation energy represented by the slope of the straight line L1 and the room temperature. The average life hr was determined. Conventionally, when one reliability test apparatus is used, three or more tests are required. According to the reliability test apparatus of the present embodiment, all the reliability is achieved in one test. The test is complete. Therefore, the time required for the reliability test could be reduced to less than half. In addition, the number of devices under test used could be reduced to one-third that of the prior art. Specifically, the activation energy of the device under test can be obtained in a test time of about 2500 hours by only one reliability test. Conventionally, it took about 4500 hours to add h11, h12 and h13, which are required time for the test under each temperature condition.

  In the present embodiment, the average life hr of the device under test at room temperature can be determined with higher accuracy than in the past. Conventionally, as shown in the coordinates of FIG. 4, when there are variations in the experimental results at each junction temperature, the straight line L11 when the maximum and minimum values of the experimental results are not excluded, and the maximum and minimum values are excluded The estimated values hr and hr ′ at room temperature Tr were significantly different from the straight line L12. In other words, there was an arbitrary estimation value by selecting the experimental result. On the other hand, according to this embodiment, even when a relatively large error is included in two of the ten experimental results, the eight experimental results excluding the two results are included. The straight line obtained by the least squares method based on is not significantly different from that based on 10 experimental results. That is, there is little arbitraryness of the estimated value by selection of an experimental result. Therefore, the activation energy of the device under test can be obtained with relatively high accuracy in a shorter time than before, and the average life of the device under test at room temperature can be estimated.

(Second Embodiment)
In the reliability testing apparatus according to the second embodiment of the present invention, the cassette 11 as a pedestal has a plurality of temperature adjustment regions corresponding to the respective fixed portions 2, and the plurality of temperature adjustment regions can be adjusted to different temperatures. On the other hand, the point which does not arrange | position a thermal resistor in the said fixing | fixed part 2 differs from 1st Embodiment.

  In the reliability test apparatus of the present embodiment, the cassette as a pedestal has ten temperature control regions, and one fixing portion is provided in each of the ten temperature control regions. The fixed portion is not provided with a thermal resistor and has the same thermal resistance.

  The temperature control region of the cassette is controlled so that the first region at one end of the cassette is about 80 ° C., and the temperature is gradually increased as the region is at the other end, and the tenth region at the other end. Is controlled to be about 160 ° C. That is, temperature control is performed so that the temperature of each region increases linearly from the first region to the tenth region. The temperature control in this temperature control region is performed by a control unit connected via a connection terminal.

  In the reliability test apparatus according to the present embodiment, the 10 elements to be tested fixed to the 10 fixed portions are supplied with power under a current condition of 3.3 V and 0.6 A current. The temperature control region of the cassette is temperature controlled so that the temperature rises from the first region toward the tenth region. As a result, the ten devices under test generate heat having a value determined by Rth · P under the environmental temperature controlled in accordance with the temperature control region. As a result, the junction temperature Tj of the ten devices under test becomes 180 ° C. for the first device under test, and then increases linearly, reaching 270 ° C. for the tenth device under test. As a result of performing the test once under this temperature condition, the device under test having a junction temperature Tj of 180 ° C. has the longest life of about 2500 hours. With respect to the lifetime values of the ten devices under test obtained from this experimental result, a straight line is drawn by the least square method at the same coordinates as in FIG. 2, and the activation energy is obtained from the slope of this straight line, and the average at room temperature is obtained. A lifetime MTTF was obtained. According to the reliability test apparatus of the present embodiment, an average life at room temperature can be obtained by one test, so that the test is performed in comparison with a conventional reliability test apparatus that requires three or more tests with different temperature conditions. The time required for this can be greatly reduced. In addition, the number of devices under test required for the reliability test can be reduced to one third of the conventional one.

  In the above embodiment, ten fixed portions 2 and 12 are provided in the cassettes 1 and 11, and ten devices under test were tested. However, the number of fixed portions 2 and 12 installed is any number other than ten. Alternatively, the test may be performed on the elements under test other than ten at the same time. In this case, the temperature of each temperature control region may be controlled so that a predetermined junction temperature can be obtained by changing the number of temperature control regions of the cassette 11 according to the number of the fixing parts 12.

1 is a schematic plan view illustrating a semiconductor device reliability test apparatus according to a first embodiment. FIG. It is a schematic sectional drawing in the A-A 'line of FIG. 1A. It is the figure which showed a mode that the average lifetime of room temperature was calculated | required from the result of a reliability test. It is a schematic plan view which shows the conventional reliability test apparatus. It is a schematic sectional drawing in the B-B 'line of FIG. 3A. It is the figure which showed a mode that the average lifetime of room temperature was calculated | required from the result of the conventional reliability test.

Explanation of symbols

1 cassette 2 fixed part 3 connection part 4 connection terminal

Claims (6)

A pedestal with adjustable temperature,
A plurality of fixing portions provided on the pedestal to which the device under test is fixed;
A plurality of thermal resistors each provided in the fixed portion and having different thermal resistances;
A semiconductor device reliability testing apparatus comprising: power supply means for supplying driving power to the device under test. A pedestal having a plurality of temperature control regions that can be adjusted to different temperatures;
A fixed portion provided in each of the plurality of temperature control regions of the pedestal, to which the device under test is fixed;
A semiconductor element reliability test apparatus comprising: a power supply means for supplying driving power to the element under test. In the reliability testing apparatus for semiconductor elements according to claim 1 or 2,
Temperature measuring means for measuring the temperature of the device under test;
Based on the temperature of the device under test measured by the temperature measuring means and the driving power supplied to the device under test by the power supply means, the thermal resistance of the device under test in the state of being arranged in the fixed portion A semiconductor device reliability test apparatus comprising: a thermal resistance detection means for detecting a thermal resistance.   A reliability test method for a semiconductor device, wherein the same drive power is supplied to a plurality of devices under test and the devices under test are simultaneously driven at different temperatures. The reliability test method for a semiconductor device according to claim 4,
A method of testing a reliability of a semiconductor device, wherein the plurality of devices under test are connected to a plurality of devices under test by connecting thermal resistors having different thermal resistances. The reliability test method for a semiconductor device according to claim 4,
A reliability test method for a semiconductor device, wherein the temperatures of the plurality of devices under test are made different from each other by making the temperatures of the environments where the devices under test are arranged different from each other.

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