JPH0536785A - Method and apparatus for burn-in - Google Patents

Abstract

PURPOSE:To improve a burn-in test. CONSTITUTION:In a burn-in method, a plurality of semiconductor devices to be tested, which are provided with semiconductor chips at the inside, are placed under surroundings at a prescribed temperature Ta, an electric current is applied to a plurality of semiconductor chips and they are tested. In the burn-in method, temperature sensors (e.g diodes) are formed in advance in the plurality of semiconductor chips, and the electric characteristic (e.g. the I-V characteristic) of the temperature sensors is detected individually during the test. Thereby, the temperature of the semiconductor chips is measured individually. When the measured result of the temperature of any one of the semiconductor chips becomes a high temperature outside a preset permissible range, an electric current is stopped at all the devices.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burn-in method and apparatus, and more particularly to a burn-in (high temperature continuous operation) test in which a semiconductor device as a device under test is subjected to a temperature load and an electric load.

[0002]

2. Description of the Related Art A burn-in test is essential for predicting the life of semiconductor devices and detecting early failures in the screening process. Generally, the burn-in test is performed as follows. FIG. 6 is a perspective view of the burn-in board 1. A plurality of sockets 3 in which semiconductor devices (not shown) to be tested are set are provided on a board 2 made of heat-resistant resin or the like, and one end of the board 2 has an external terminal for making electrical contact with the outside. 4 are provided.
At the other end of the board 2, a handle 5 is provided for an operator to operate the burn-in board 1. The terminals (not shown) of the socket 3 and the external terminals 4 are connected by the wiring (only part of which is shown) on the board 2.

Such a burn-in board 1 is set in a burn-in test container 6 as shown in FIG. That is, the burn-in test container 6 includes a housing 61, which is a main body, and a lid 6
2 has a structure in which they are connected by a hinge mechanism 63, and an insertion slit 65 of a board connector 64 provided inside
Burn-in board 1 is inserted in. As a result, the external terminal 4 of the burn-in board 1 and the terminal (not shown) of the board connector 64 are connected. Through this connection, the semiconductor device is energized by an unillustrated energizing device. Although not shown, the burn-in test container 6 is provided with a temperature adjusting device, and usually has a structure in which hot air is supplied into the burn-in test container 6 or a heater is provided.

It should be noted that the internal temperature of the burn-in test container 6, that is, the environmental temperature T of the semiconductor device which is the device under test.
_“A” is measured by a temperature sensor provided near the inner wall of the housing 61. The burn-in test is conventionally performed by monitoring the measured temperature and controlling the temperature adjusting device.

[0005]

However, in the above-mentioned prior art, the burn-in test could not be suitably performed for the following reasons. That is, it is the environmental temperature T of the device under test that can be monitored in real time by the conventional technique.
_a , which is the surface temperature of the semiconductor chip, especially p
It does not match the junction temperature T _{j at the} n-junction portion or the Schottky junction portion. Since the failure of the semiconductor device depends on the junction temperature T _j , conventionally, the junction temperature T _j is estimated from the result of measuring the environmental temperature T _a and the burn-in test is performed. However, this examine the relationship between the environmental temperature T _a and the junction temperature T _j requires a very complicated task, the size of semiconductor devices, formats, such as specifications require a separate estimated work each time different. Moreover, the temperature is not uniform in the position in the test apparatus, and the heat generation amount of the semiconductor device is different from each other. Therefore, the temperature of the device under test is not the same. Therefore, it is difficult to perform a simple and accurate burn-in test with a high yield.

Therefore, the present invention has an object to provide a burn-in method and apparatus capable of accurately controlling the temperature of the chip itself in the device under test to which the burn-in test is applied and further improving the yield of the screening test. And

[0007]

According to the present invention, a burn-in is performed in which a plurality of semiconductor devices as a device under test having a semiconductor chip inside are placed under an environment of a predetermined temperature and a current is applied to the plurality of semiconductor chips. In the method, a temperature sensor is formed in advance on at least two of the plurality of semiconductor chips, and the temperature of each semiconductor chip is measured by detecting the electrical characteristics of the temperature sensor during the test. When the temperature measurement result is equal to or higher than a preset allowable temperature, power supply to all the semiconductor chips is stopped and then restarted.

Further, the present invention provides a burn-in apparatus comprising a test container containing a plurality of semiconductor devices as devices under test having semiconductor chips therein, and an energizing means for supplying electric power to the plurality of semiconductor chips, Measuring means for measuring the temperature of each of the semiconductor chips by detecting the electric characteristics of temperature sensors formed in advance in at least two of the plurality of semiconductor chips during the test, respectively, and measuring values obtained by the output of the measuring means. When any one of them reaches a preset allowable temperature or higher, it is characterized by including a control means for stopping the operation of the energizing means and then restarting the operation.

[0009]

According to the burn-in method of the present invention, the temperature sensor is provided on the semiconductor chip itself inside the semiconductor device,
Since this is monitored, the temperature of the semiconductor chip itself can be accurately controlled. Then, when the temperature of any of the devices becomes higher than or equal to the set temperature, the temperature is lowered by stopping the energization, whereby the yield of screening can be improved.

Further, in the burn-in apparatus of the present invention, the temperature sensor provided on the semiconductor chip is monitored by the measuring means, and when the temperature of any device becomes high as a result, the energizing means is stopped and controlled. Therefore, by setting a program for the stop control in the control means, the stop control can be automatically and accurately performed.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a burn-in method according to an embodiment.
A flow chart, FIG. 2 is a conceptual diagram of the apparatus used for this.
It As shown in Fig. 2, the inside of the burn-in test container 6 is
Conductor chip 7 (7₁, 7₂, 7₃) Inside
A body device (not shown) is set and the semiconductor chip
P7₁, 7₂, 7₃Integrated circuit 71₁, 71₂, 71
₃And temperature detecting diode 72 as a temperature sensor₁，
72₂, 72₃Are formed. Burn-in test container
6 is provided with a temperature adjusting device 8 for supplying hot air or
The heater is heated. Each semiconductor
Chip 7₁~ 7 ₃Integrated circuit 71₁~ 71₃Energizing equipment
An electric load is applied from the storage 91,
Degree detection diode 72₁~ 72₃Electrical characteristics (especially
Lift voltage V_FChange) by the temperature detector 92
Monitored, junction temperature T_jSemiconductor chip 7
₁~ 7₃It is designed to be measured every time.

The control device 93 controls the energization amount by the energizing device 91 and the air blowing amount by the temperature adjusting device 8 based on the monitoring result of the temperature detector 92. The controller 93 _stores the allowable maximum temperatures of the junction temperatures T _{j1 to} T _j3 in the burn-in test and an appropriate test temperature, and controls either the current-carrying device 91 or the temperature adjusting device 8 in comparison with the monitor result. It is pre-programmed to stop the energization operation when the device temperature reaches a high temperature outside the allowable range, and resume the energization when the device temperature returns to the proper temperature.

The stop control in the above test operation will be described in more detail as shown in the flow chart of FIG. First, an allowable maximum temperature and an appropriate test temperature are set by an operator and stored in a memory or the like (step 101). When testing begins, the electrical characteristics of a plurality of temperature detecting diode 72 _{1-73 3} are measured, the junction temperature T _j1 through T _j3 devices are individually monitored (step 102). Then, it is checked whether or not the temperature of the device exceeds the maximum allowable temperature (step 103), and if the measured value of any of the devices exceeds the maximum allowable temperature, the electric loads (energization) of all the devices are stopped. (Step 104). Then, the above energization is continuously stopped until the temperature reaches the proper test temperature, and when the temperature reaches the proper temperature, energization to all devices is restarted (steps 105 and 106).

As a result, the screening test is prevented from being altered into a test having a different purpose, and the test yield is improved. In particular, the environmental temperature T _a inside the burn-in test container 6 in which the test is executed varies in position depending on the position of the heater for heating or the air blowing port, or the wind direction or air volume, and therefore may become too high for a certain device. . In the present invention, since the burn-in test itself is stopped in such a case, it is possible to ensure the screening. In addition, it is desirable to monitor the time when power supply is stopped separately and exclude it from the screening time.

FIG. 3 shows the semiconductor chip 7 in the above embodiment.
And the IV characteristic of the temperature detecting diode 72 (see FIG. 11B).
As shown, an integrated circuit 71 and a temperature detection diode 72 are formed on the semiconductor chip 7, and the integrated circuit 71
A current-carrying pad 73 connected to and a monitoring pad 74 connected to the anode and cathode of the temperature detecting diode 72 are provided. Such a semiconductor chip 7 is packaged as a flat package or a leadless chip carrier (LCC) to form a semiconductor device as a device under test. Such temperature monitoring in the semiconductor chip 7 is performed by observing the IV characteristic of the temperature detecting diode 72. That is, since the rising voltage V _F of the IV characteristic shown in FIG. 3B changes linearly with temperature, the change in the rising voltage V _F causes the junction temperature T _F to change.
_j can be accurately determined.

4 and 5 show the semiconductor device 7 which is the device under test in the burn-in apparatus of the above embodiment.
0 is mounted on the socket 3, FIG. 4 is a perspective view, and FIG. 5 is a sectional view. The socket 3 has a base 31 and a lid 32, which are openably and closably coupled by a hinge 33 and closed by engagement of a lever 34 and a hook 35. When the through hole 36 is formed in the central portion of the base 31, a cross-shaped recess 37 is formed from the upper surface, and the terminal 38 is provided therein. Then, one end of the terminal 38 has the base 31
Of the burn-in board 1 and is connected to the wiring on the burn-in board 1. Further, in the central portion of the lid 32, the heat dissipation member 39
Is screwed on. On the other hand, a terminal 76 is provided on the bottom surface of the semiconductor device 70, and when mounted on the socket 3, the terminal 76 contacts the terminal 38 of the socket 3. When the semiconductor device 70 is mounted in the recess 37 and the lid 32 is closed, the bottom surface of the heat dissipation member 39 contacts the top surface of the semiconductor device 70, and heat dissipation is achieved.

According to the above embodiment, the temperature of the semiconductor chip 7 itself can be monitored with extremely high accuracy. That is, the temperature of the semiconductor chip 7 itself depends not only on the environmental temperature T _a but also on the heat generation in the integrated circuit 71 and the heat radiation to the outside, and the heat generation amount and the heat radiation amount vary greatly depending on the mounting state and the like. large. However, in this embodiment, since the junction temperature T _j of the temperature detecting diode 72 provided in the semiconductor chip 7 is monitored, the temperature of the semiconductor chip 7 can be directly measured. Then, when the temperature of any of the plurality of semiconductor chips exceeds the set value, all the energization is stopped, so that it is not necessary to test at an unnecessarily high temperature. Therefore, for example, when the allowable maximum temperature is set to 160 ° C. and the monitored temperature becomes 160 ° C. or higher for any one device, naturally, energization is stopped for all devices. And an appropriate temperature (for example, 150
(° C), the power supply to all devices is restarted.

The temperature sensor according to the present invention is not limited to the temperature detecting diode formed on the semiconductor chip separately from the integrated circuit 71, but a diode inside the integrated circuit may be used, or as a transistor. Good. Also, a NiCr-based metal thin film resistor may be formed on the semiconductor chip. Further, the temperature may be monitored for all the semiconductor chips, or only the position where the environmental temperature is predicted to be high may be monitored.

[0020]

As described above, according to the burn-in method of the present invention, since the temperature sensor is provided in the semiconductor chip itself inside the semiconductor device and is monitored, the temperature of the semiconductor chip itself can be controlled accurately. Then, if the temperature of any of the devices becomes too high, the power supply to all the devices is stopped. Therefore, it becomes possible to perform a simple and accurate burn-in test with high yield and reliability.

Further, in the burn-in device of the present invention, the measuring means monitors the temperature sensor provided on the semiconductor chip, and the stop of the energizing means is controlled based on the result. Therefore, by setting a stop control program in the control means, the burn-in test can be automatically and accurately performed.

[Brief description of drawings]

FIG. 1 is a flowchart showing an example method.

FIG. 2 is a conceptual diagram of a burn-in device according to an embodiment.

FIG. 3 is a diagram showing a configuration of a semiconductor chip 7 and characteristics of a temperature detecting diode 72 in the example.

FIG. 4 is a perspective view of the socket 3 in the embodiment.

FIG. 5 is a cross-sectional view of the socket 3 in the embodiment.

FIG. 6 is a perspective view showing a configuration of a burn-in board 1.

FIG. 7 is a perspective view of a burn-in test container 6.

[Explanation of symbols]

1 ... Burn-in board 2 ... Board 3 ... Socket 31 ... Base 32 ... Lid 34 ... lever 35 ... Hook 38 ... Terminal 39 ... Heat dissipation member 6 ... Burn-in test container 7 ... Semiconductor chip 70 ... Semiconductor device 71 ... Integrated circuit 72 ... Diode for temperature detection 8 ... Temperature control device 91 ... energizing device 92 ... Temperature detector 93 ... Control device

Claims (2)

[Claims] 1. A burn-in method for conducting a test by placing a plurality of semiconductor devices as devices under test having semiconductor chips therein under an environment of a predetermined temperature and conducting a test by energizing the plurality of semiconductor chips. Temperature sensors are formed in advance on at least two of the chips, and the temperature of each of the semiconductor chips is measured by detecting the electrical characteristics of each of the temperature sensors during the test. When the measurement result of is equal to or higher than a preset allowable temperature, the energization is stopped for all of the plurality of semiconductor chips, and energization is restarted when the measurement result reaches a predetermined temperature. Burn-in method. 2. A burn-in apparatus comprising: a test container in which a plurality of semiconductor devices as devices under test having semiconductor chips are housed; and energizing means for supplying electric power to the plurality of semiconductor chips. Any one of measuring means for respectively measuring the temperature of the semiconductor chip by detecting the electric characteristics of the temperature sensors formed in advance in at least two of the semiconductor chips during the test, and the measured value by the output of the measuring means. However, the burn-in device is provided with: a control means for stopping the operation of the energizing means when the temperature becomes equal to or higher than a preset allowable temperature and restarting the energization when the temperature becomes equal to or lower than a predetermined temperature.