JPH0536790A - Method and apparatus for burn-in - Google Patents

Abstract

PURPOSE:To control the temperature of a plurality of semiconductor chips themselves nearly uniformly by a method wherein temperature sensors are installed at individual semiconductor devices in the semiconductor chips themselves at the inside of the semiconductor devices, the sensors are monitored and a laser irradiation operation is controlled at the individual devices according to monitored results. CONSTITUTION:A plurality of burn-in boards are installed at the inside of a burn-in (high-temperature continuous operation) test container 6; semiconductor devices which are provided with semiconductor chips 71 to 73 at the inside are set on the boards. Integrated circuits 711 to 713 and diodes 721 to 723 for temperature detection use are formed on the semiconductor chips 71 to 73. The electric characteristic of the diodes 72 for temperature detection use is monitored individually by using a temperature detector 92. A control device 93 controls an electricity-feeding amount by an electricity-feeding device 91 on the basis of monitored results by the temperature detector 92 and controls the irradiation direction with a laser beam LTB from a laser source 83. Thereby, the temperature of the semiconductor chips themselves can be controlled with good accuracy and uniformly.

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 Ta 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. Therefore, it is difficult to perform a simple and accurate burn-in test. Also,
Since the environmental temperature T _a differs depending on the position in the test container 6 and the heat generation amount of each semiconductor device is not the same, it is not easy to screen a large number of devices under the same conditions.

Therefore, an object of the present invention is to provide a burn-in method and apparatus capable of accurately controlling the temperature of the chip itself in a plurality of devices under test to which a burn-in test is simultaneously performed.

[0007]

According to the present invention, a plurality of semiconductor devices as devices under test having semiconductor chips therein are placed in an environment of a predetermined temperature in a test container, and the plurality of semiconductor chips are energized. In the burn-in method of performing a test, a temperature sensor is formed in advance on each of a plurality of semiconductor chips, and the temperature of each of the plurality of semiconductor chips is measured by detecting the electrical characteristics of the plurality of temperature sensors during the test. Based on the measurement result of 1., the plurality of semiconductor devices are selectively irradiated with the laser beam so that the temperatures of the plurality of semiconductor devices are substantially the same.

Further, according to the present invention, in a burn-in apparatus comprising a test container accommodating a plurality of semiconductor devices and an energizing means for supplying electric power to a plurality of semiconductor chips, a laser for irradiating a laser beam to the plurality of semiconductor devices A light source and measuring means for measuring the temperature of each of the plurality of semiconductor chips by detecting the electrical characteristics of the temperature sensor formed in advance in each of the plurality of semiconductor chips during the test, and based on the output of this measuring means. A control means for controlling laser beam irradiation to the plurality of semiconductor devices is provided so that the temperatures of the plurality of semiconductor chips are substantially the same.

[0009]

According to the burn-in method of the present invention, the temperature sensor is provided for each device on the semiconductor chip itself inside the semiconductor device, the temperature sensor is monitored, and the laser beam irradiation is controlled for each device according to the result. Because
The temperatures of the plurality of semiconductor chips themselves can be controlled accurately and substantially uniformly.

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 the laser light source is controlled based on the result to irradiate the laser beam to each device. Therefore, by setting a program for uniformly controlling the temperature by laser beam irradiation in the control means, it is possible to automatically and substantially accurately control the temperature.

[0011]

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

FIG. 1 is a conceptual diagram of a burn-in system according to an embodiment. A plurality of burn-in boards (not shown) are provided inside the burn-in test container 6, and semiconductor devices (not shown) having semiconductor chips 7 _{1 to} 7 ₃ therein are provided by sockets (not shown). The integrated circuits 71 _{1 to} 71 ₃ are set in the semiconductor chips 7 _{1 to} 7 ₃
And a temperature detection diode 72 ₁ as a temperature sensor
72 ₃ is formed. A temperature adjusting device 8 is attached to the burn-in test container 6 to supply hot air.

A laser irradiation device 83 is attached to the burn-in test device 6 so that a plurality of semiconductor devices are irradiated with the laser beam LB from the laser irradiation device 83 individually and selectively. An electric load is applied to the integrated circuit 71 of the semiconductor chip 7 independently of the energization device 91, and the electric characteristics (especially the change of the rising voltage V _F ) of the temperature detecting diode 72 are individually detected by the temperature detector 92. The junction temperature T _j is measured for each device.

The control device 93 controls the energization amount by the energization device 91 based on the monitoring result of the temperature detector 92, and the irradiation direction of the laser beam LB from the laser light source 83 is passed through a mirror (not shown) or the like. Control. Therefore, the control device 93 stores the allowable range of the junction temperature T _j in the burn-in test, and controls the energization device 91 and the irradiation direction of the laser beam from the laser light source 83 in comparison with the monitor result.
Pre-programmed.

FIG. 2 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. 2A 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.

3 and 4 show a semiconductor device 7 which is a device under test in the burn-in apparatus of the above embodiment.
0 is mounted on the socket 3, FIG. 2 is a perspective view, and FIG. 3 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, an opening is formed in the center of the lid 32, and a laser irradiation window 39 is provided therein. on the other hand,
Terminals 76 are provided on the bottom surface of the semiconductor device 70, and the terminals 76 of the socket 3 are mounted by being mounted on the socket 3.
Contact with. When the semiconductor device 70 is mounted in the recess 37 and the lid 32 is closed, the periphery of the opening on the bottom of the lid 32 contacts the upper surface of the semiconductor device 70, and the semiconductor device 70
Irradiation of a laser beam onto the laser is enabled. A heat dissipation member (not shown) may be separately provided to improve the efficiency of heat dissipation.

According to the above-described embodiment, the temperature of the semiconductor chip 7 itself can be monitored with extremely high accuracy for any of the plurality of chips. That is, the temperature of the semiconductor chip 7 itself is not only dependent on the different environmental temperature T _a by the position of the internal test apparatus is also dependent on the heat dissipation of the heating and the external in the integrated circuit 71, the heating value and heat radiation amount Has a large variation due to the mounting condition. However,
In this embodiment, since the junction temperatures T _j of the temperature detecting diodes 72 provided on the semiconductor chips 7 are individually monitored, the temperatures of all the semiconductor chips 7 can be directly measured.

Therefore, by using this monitoring result, the irradiation of the laser beam can be controlled independently for each semiconductor device 70, and the surface temperature (junction temperature T _j ) of the entire semiconductor chip 7 can be accurately and uniformly controlled. . That is, the temperature is made uniform by selectively irradiating the device having the low temperature with the laser beam. Specifically, if there is a low-temperature device, the device may be irradiated with a laser beam, and irradiation may be stopped when the temperature reaches an appropriate value. As a result, it is possible to realize the accuracy of screening and the improvement of the yield at the same time.

For example, in screening a large number of semiconductor devices that generate heat of 50 W, when the temperature resistance θ _ja = 2 ° C./W, the junction temperature Tj = 150 ° C., the environmental temperature T _a = 50 ° C. may be set. . And
When the temperature of a certain device reaches 140 ° C., it is irradiated with a laser beam, and when the temperature returns to 150 ° C., irradiation of the laser beam may be 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, in the embodiment, the laser irradiation window 3
Although the semiconductor device is irradiated with the laser beam via 9, the semiconductor device may be heated by embedding a laser beam absorbing member in the opening of the lid 32 and heating the member. Further, this member may have a role of heat dissipation.

FIG. 5 shows an example of switching the laser beam irradiation. As shown, three burn-in boards 1a to 1c are provided inside the burn-in test device 6,
Correspondingly to this, three laser light sources 83a to 83 are externally provided.
c is provided. When the laser beam enters the burn-in test equipment 61, the galvanometer mirrors 84a ...
Each of the light beams is reflected by 84c and is irradiated onto a desired (low monitor temperature) semiconductor device 70. This makes it possible to control the temperature uniformity of many semiconductor devices.

[0022]

As described above, according to the burn-in method of the present invention, the temperature sensor is provided on the semiconductor chip itself inside the semiconductor device, and the temperature sensor is monitored and the laser beam is selectively irradiated by the temperature sensor. The temperature of the semiconductor chip itself can be controlled accurately and uniformly. Therefore, it is possible to perform a burn-in test with high yield and with high accuracy.

Further, in the burn-in device of the present invention, the temperature sensor provided in each of the plurality of semiconductor chips is monitored by the measuring means, the laser beam light source is controlled based on the result, and the laser beam is selectively irradiated. To be done. Therefore, by setting a laser beam control program in the control means, it is possible to automatically and accurately perform uniform temperature control.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a burn-in device according to an embodiment.

FIG. 2 is a diagram showing a configuration of a semiconductor chip 7 and characteristics of a temperature detecting diode 72 in the example.

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

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

FIG. 5 is a diagram showing an example of switching laser beam irradiation.

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 ... Laser irradiation window 6 ... Burn-in test container 7 ... Semiconductor chip 70 ... Semiconductor device 71 ... Integrated circuit 72 ... Diode for temperature detection 83 ... Laser irradiation device (laser light source) 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 in a test container and energizing the plurality of semiconductor chips. A temperature sensor is formed in advance on each of the plurality of semiconductor chips, and the temperature of each of the plurality of semiconductor chips is measured by detecting the electrical characteristics of the plurality of temperature sensors during a test. Based on the above, the burn-in method is characterized in that the plurality of semiconductor devices are selectively irradiated with a laser beam so that the temperatures of the plurality of semiconductor devices are substantially the same. 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. A laser light source for irradiating a semiconductor device with a laser beam, and a measurement for measuring the temperature of each of the plurality of semiconductor chips by detecting the electrical characteristics of a temperature sensor formed in advance in each of the plurality of semiconductor chips during a test. Means and a control means for controlling the laser beam irradiation to the plurality of semiconductor devices so that the temperatures of the plurality of semiconductor chips are substantially the same based on the output of the measuring means. .