JPH0536779A - Method and apparatus for burn-in - Google Patents

Abstract

PURPOSE:To control the temperature of semiconductor chips themselves with good accuracy and to enhance the yield of a screening test by a method wherein a temperature sensor is installed at the semiconductor chip itself at the inside of a semiconductor device, the sensor is monitored and a test is stopped when a temperature difference between devices becomes a temperature outside a set range. CONSTITUTION:Semiconductor devices which are provided with semiconductor chips 71, 72, 73 at the inside are set at the inside of a burn-in (high-temperature continuous operation) test container 6. Integrated circuits 711, 712, 713 and diodes 721, 722, 723 for temperature detection use are formed in the semiconductor chips 71, 72, 73. The electric characteristic of the diodes 721 to 723 for temperature detection use is monitored individually by using a temperature detector 92. A control device 93 controls a current-carrying device 91 and a temperature- adjusting device 8 by comparing monitored results by means of the temperature detector 92. When a temperature difference becomes outside a permissible range, a test operation is stopped. Thereby, a simple and good-accuracy burn-in test can be performed at high yield and with high reliability.

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 was not uniform at the positions in the test apparatus, and therefore the temperature of the device under test was not the same between them. 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, temperature sensors are 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 each temperature sensor during the test. The feature is that the test is stopped when the difference between the measurement results is outside the preset allowable range.

Further, the present invention is a test container containing a plurality of semiconductor devices as devices under test having a semiconductor chip therein, and temperature control means for adjusting the temperature inside the test container to a predetermined value. In a burn-in device including an energizing means for supplying electric power to a 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 the difference is outside the preset allowable range, the temperature control means and the control means for stopping the operation of the energizing means are provided.

[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 difference between the devices is out of the set range, the yield can be improved by stopping the test.

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 difference between the devices becomes large as a result, the energizing means and the temperature adjusting means are stopped and controlled. . Therefore, by setting a program for temperature control and stop control in the control means, temperature control and 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 is a flow chart showing a burn-in method according to an embodiment, and FIG. 2 is a conceptual diagram of an apparatus used therefor. As in Figure 2, inside the burn-in test container 6 semiconductor chip 7 (7 _1, 7 _2, 7 ₃₎ (not shown) semiconductor device having therein a is set, the semiconductor chip _71, 7 ₂ , 7 ₃ include integrated circuits 71 ₁ , 71 ₂ , 71
₃ and a temperature detecting diode 72 ₁ as a temperature sensor,
72 ₂ and 72 ₃ are formed. A temperature adjusting device 8 is attached to the burn-in test container 6 so that hot air is supplied or a heater is heated. Integrated circuit 71 of each of the semiconductor chips 7 _{1-7 3 1-71 3} being adapted to the electrical load is given from the energization device 91, the temperature detecting diode 72 _{1-72 3} electrical characteristics (especially threshold voltage The change in V _F ) is individually monitored by the temperature detector 92, and the junction temperature T _j is the semiconductor chip 7 ₁
It is adapted to be measured every _7-3.

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 control device 93 stores the allowable range of the difference between the junction temperatures T _{j1 to} T _j3 in the burn-in test. The temperature difference is within the allowable range while controlling the energization device 91 and the temperature adjusting device 8 in comparison with the monitor result. Pre-programmed to stop test operation when outside.

The stop control in the above test operation will be described in more detail as shown in the flow chart of FIG. First, the allowable temperature difference is set by the operator and stored in a memory or the like (step 10).
1). When the test starts, multiple temperature detection diodes 7
2 _1-73 are electrical characteristics of ₃ measurements, the junction temperature T _j1 through T _j3 devices are individually monitored (step 102). Then, the temperature difference between devices (maximum temperature difference) is calculated (step 103), and this measured value is compared with the set value in step 101 (step 10).
4). The above test is continued until the set value (allowable value) is exceeded, and when the allowed value is exceeded, the test is stopped.

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 performed differs positionally depending on the position of the heater for heating and the air outlet, or the direction and amount of air flow, so it becomes too high for some devices, and It can be too cold for the device. In the present invention, since the burn-in test itself is stopped in such a case, it is possible to ensure the screening.

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. When the temperature difference between the plurality of semiconductor chips exceeds the set value, the test is stopped so that the test is not performed at an unnecessarily high temperature. Therefore, for example, the setting is 10 ° C
Then, when the monitored temperature difference reaches 20 ° C., the device is naturally stopped.

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 difference in environmental temperature is predicted to be large 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. If the temperature difference between the devices becomes too large, the test itself 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 temperature sensor provided on the semiconductor chip is monitored by the measuring means, and the energizing means and the temperature adjusting means are controlled and the stop is controlled based on the result. Therefore, by setting the temperature control and stop control programs 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. The burn-in method, wherein the test is stopped when the difference is outside the preset allowable range. 2. A test container containing a plurality of semiconductor devices as devices under test having a semiconductor chip therein, temperature control means for adjusting the temperature inside the test container to a predetermined value, and the plurality of semiconductors. In a burn-in device provided with a current-carrying means for supplying electric power to a chip, the temperature of the semiconductor chip can be detected by detecting the electrical characteristics of temperature sensors formed in advance in at least two of the plurality of semiconductor chips during a test. And a control means for stopping the operation of the temperature adjusting means and the energizing means when the difference between the measured values due to the output of the measuring means is outside the preset allowable range. And burn-in equipment.