JPH0536783A - 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 tasted, 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 the individual semiconductor chips becomes a temperature outside a preset permissible range, an electric current to be applied to each device is controlled.

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 at the position in the test apparatus, and the heat generation due to energization differs from device to device, so that the temperature of the device under test was 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 each temperature sensor during the test. Results,
It is characterized in that the energization is controlled for each semiconductor chip when it is out of a 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,
By measuring the electrical characteristics of temperature sensors formed in advance on at least two of the plurality of semiconductor chips during the test, the measuring means for respectively measuring the temperature of the semiconductor chips and the measured value by the output of the measuring means are provided. ,
A control means for controlling the supply of electric power from the energizing means for each semiconductor chip when it is outside the preset allowable range is characterized.

[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 each device is out of the set range, it is possible to improve the yield by controlling the energization for each device.

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 each device is out of the set range as a result, the energizing means is controlled for each device. It Therefore, by setting a program for controlling energization in the control means, the temperature can be automatically and accurately controlled.

[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 individually.
The junction temperature T_jSemiconductor chip 7₁
~ 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 range of the difference between the junction temperatures T _{j1 to} T _j3 in the burn-in test, and if the temperature of the monitoring result of each semiconductor chip 7 is outside the allowable range,
The semiconductor chips 7 are individually programmed in advance to control the amount of electricity supplied by the electricity supply means 91.

The control in the above test operation will be described in more detail as shown in the flow chart of FIG. First, an allowable temperature or an appropriate test temperature is 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 separately, the junction temperature T _j1 through T _j3 devices are individually monitored (step 102). Then, the measured temperature value and the set range are compared for each device (step 1
03). The energization amount is increased for low-temperature devices below the set range (permissible range) (step 104), and when the temperature exceeds the permissible range, the energization amount for this device is decreased (step 105).

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 in position depending on the position of the heater for heating or the blower opening, or the wind direction or air volume
In addition, since the amount of heat generated by energization also varies from device to device, the temperature may become too high for some devices and too low for other devices. In the present invention, since the energization amount is controlled for each device in such a case, it is possible to ensure the screening especially for a device whose failure mode is mainly independent of the energization amount. On the other hand, the failure mode such as electromigration is a failure mode that depends on the current density, and thus the screening according to the present invention is not suitable.

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 temperatures of the plurality of semiconductor chips are out of the set range, the energization is controlled for each device, so that it is not necessary to test at an unnecessarily high temperature or low temperature. Therefore, for example, the setting is set to 145 to 155 ° C.,
When the monitored temperature reaches 140 ° C for device A and 160 ° C for device B, device A increases in power, device B increases.
Will be controlled to reduce energization.

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. Then, when the monitoring result for each device is out of the temperature setting range, energization is controlled for each device. For this reason,
A simple and accurate burn-in test can be performed with high yield and reliability.

In the burn-in apparatus of the present invention, the temperature sensor provided on the semiconductor chip is monitored by the measuring means, and the energizing means is controlled for each device based on the result. Therefore, by setting a program for energization control for each device 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. A temperature sensor is formed in advance on at least two of the chips, and the temperature of each of the semiconductor chips is measured by detecting an electric characteristic of each of the temperature sensors during a test. However, when the current value is out of a preset allowable range, the energization is controlled for each semiconductor chip. 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. When the measuring means for measuring each and the measured value by the output of the measuring means are outside the preset allowable range, a control means for controlling the operation of the energizing means for each semiconductor chip which is outside the allowable range. A burn-in device comprising: