JPH0499972A - Low temperature tester for high speed semiconductor device - Google Patents

Abstract

PURPOSE:To eliminate contact inferiority or the reflection loss of a signal and to perform a test of good reproducibility by connecting a conversion connector and a cable to the side wall of a container filled with a cooling medium and replacing a semiconductor device in the gaseous atmosphere. of the cooling medium. CONSTITUTION:A semiconductor device 20 is mounted on a substrate 1 and the cable 15 connected to a measuring device is connected to a conversion connector 3. Next, a cooling medium (liquid nitrogen) 8 is sent into a container 5 through a pipe 12 and a liquid level 9 is raised until the device 20 is perfectly immersed in the cooling medium 8 and, when the device 20 is stabilized at predetermined temp. by a heater 6, a high frequency signal is supplied through the cable 15 to perform a predetermined test. By this method, it is unnecessary to connect and detach the connector 3 and the cable 15 at every test and, since the cable 15 is fixed, contact inferiority, the reflection loss of a signal and the fluctuation of the characteristic impedance of the cable 15 are not generated and a characteristic test of good reproducibility can be conducted. Since the device 2 is mounted and detached in the cooling medium gas, the contact inferiority or current leak due to the condensation of steam can be prevented.

Description

[Detailed Description of the Invention] [Summary] Regarding a device for testing high-speed semiconductor devices in a temperature range from room temperature to liquid nitrogen temperature or lower, fluctuations in characteristic impedance due to twisting of cables for transmitting high frequency signals or conversion connectors and To enable accurate characteristic evaluation by eliminating poor connection caused by loosening or deformation of the connection part with the cable due to external force, reflection loss of the signal, etc. The purpose is to make it observable.

A container (5) with a heat-insulating structure filled with liquefied refrigerant, a conversion connector (3) fixed to a side wall of the container (5), and one end extending into the interior of the container (5) through the side wall. and the other end connected to the conversion connector (3) and the container (
5) The one end extending inside the substrate (
a transmission line (2) connected to the substrate (1), and a heater (6) provided on the substrate (1) to heat the object to be measured.
) and means for introducing and discharging the refrigerant in order to change the level of the refrigerant in the container (5);
5) On the top is a hollow transparent window with a vacuum inside (7)
The low-temperature test equipment for high-speed semiconductor devices is configured so as to be provided with:

[Industrial application field]

The present invention relates to an apparatus for testing a high-speed semiconductor device having a cutoff frequency (f,) of about 20 GHz in a temperature range from around room temperature to below liquid nitrogen temperature.

[Conventional technology]

An overview of a conventional low-temperature test apparatus for high-speed semiconductor devices will be explained with reference to FIG. As shown in FIG. 2(a), the conventional device includes a high-frequency line base 24 on which a semiconductor device 20 is mounted.
It has a structure in which the container 25 and the container 25 filled with a refrigerant for cooling the semiconductor device 20 are separated. In the figure, reference numeral 26 is a high frequency cable connected to an external circuit such as a measuring instrument.

FIG. 2B is a detailed view of the high frequency line base 24.

The high frequency line base 24 is composed of a substrate 21 made of an insulator, a transmission line 22, and a conversion connector 23. The semiconductor device 20 is fixed by pressing its back surface and its leads to the substrate 21 using a fixing jig (not shown). One end of the transmission line 22 is connected to a conversion connector 23, and the other end is connected to an electrode (
(not shown).

After the high frequency line base 24 is immersed in a refrigerant and the semiconductor device 20 reaches a predetermined temperature, the cable 2 is connected to the conversion connector 23.
Connect 6. This makes it possible to exchange high-frequency signals between the semiconductor device 2o and the external circuit, and a predetermined low-temperature characteristic test is performed. When the exam is finished.

First, remove the cable 26 from the conversion connector 23.

The high frequency line base 24 is taken out of the container 25. Then, after returning the semiconductor device 20 to room temperature by, for example, blowing nitrogen gas on it, the semiconductor device 20 is removed from the substrate 21 .

[Problem to be solved by the invention]

In the conventional low temperature test equipment described above, it is necessary to connect and disconnect the cable 26 for each semiconductor device 20.
The connection between the conversion connector 23 and the cable 26 may become unstable or tightened.

If the tightening is too strong, the connection will become deformed. As a result, poor connection and reflection of high-frequency signals occur at this connection, resulting in increased transmission loss.In addition, the cable 26 has a characteristic impedance due to twisting that occurs when it is repeatedly connected and disconnected from the conversion connector 23. fluctuate,
As a result, signal delays and distortions occur, resulting in the problem that the reproducibility of characteristic test results is insufficient. These problems become more pronounced with high frequency signals.

Furthermore, when the semiconductor device 20 is removed from the high frequency line base 24 as described above, the high frequency line base 24 is exposed to the atmosphere. At this time, water vapor in the atmosphere is transferred to the high frequency line base 24.
Condenses on the surfaces of various parts. The moisture generated in this way is
There is a problem in that the surface of the metal member in the high-frequency line base 24 is oxidized, resulting in poor contact, or remains on the surface until the fifth test, causing current leakage. Furthermore, due to the structure of the device, it was impossible to observe the semiconductor device 20 under test using a microscope or the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide a low-temperature test apparatus for high-speed semiconductor devices in which the above-mentioned conventional problems are solved.

[Means to solve the problem]

The above purpose is to provide a container (5) with a heat insulating structure filled with liquefied refrigerant, a conversion connector (3) fixed to the side wall of the container (5), and a conversion connector (3) that penetrates the side wall to connect the container (5). It has one end extending inside and the other end connected to the conversion connector (3), and the one end extending inside the container (5) is connected to the substrate (1) on which the object to be measured is mounted. transmission line (2)
a heater (6) provided on the substrate (1) for heating the object to be measured; and a heater (6) for feeding the refrigerant in order to change the height of the liquid level of the refrigerant in the container (5). A low-temperature testing apparatus for high-speed semiconductor devices according to the present invention, characterized in that it is equipped with means for inlet and outlet, or in the above, the upper surface of the container (5) has a hollow space inside which is evacuated. This is achieved by the low-temperature testing apparatus for high-speed semiconductor devices of the present invention, which is characterized in that it is provided with a transparent window (7).

There is no risk of poor contact or current leaks due to condensed water vapor. Furthermore, a heat-insulating observation window is provided at the top of the container, and the height of the refrigerant inside the container can be adjusted, so that the semiconductor device during the 5 tests is not immersed in the refrigerant. microscopic observation is possible.

[For production]

In the low temperature test equipment for high-speed semiconductor devices of the present invention, since the conversion connector and cable are fixed to the side wall of the container filled with refrigerant, the conversion connector and cable must be connected and disconnected for each semiconductor device. No need,
In addition, it is possible to fix the cable outside the container so that it does not twist. Therefore, it is possible to prevent connection failures and signal reflection losses as in the conventional low-temperature test equipment, or to reduce the characteristic impedance of the cable. Since no fluctuations occur, it is possible to perform characteristic tests with good reproducibility.Furthermore, when replacing a semiconductor device, there is no need to take out the board on which it is mounted into the atmosphere [Example] Examples of the present invention are shown in the drawings below. Explain with reference to.

FIG. 1 is a schematic diagram for explaining the structure of a low-temperature testing apparatus for high-speed semiconductor devices according to the present invention, in which FIG. 1(a) is a sectional view and FIG. 1(b) is a top view. Reference numeral 5 denotes a cylindrical container made of, for example, a stainless steel double tube, and the inside of the double tube is evacuated to provide heat insulation properties.

on the side wall of container 5.

Through holes having an airtight sealing structure for maintaining the vacuum of the double tube are arranged radially, and a plurality of SMA conversion connectors 3 are fixed to the external side wall in correspondence with the through holes. For each conversion connector 3.

For example, one end of a semi-rigid coaxial transmission line 2 is connected. The other end of the transmission line 2 extends into the container 5 through the side wall of the container 5, and is an object to be measured.

For example, it is connected to an electrode (not shown) provided on a substrate 1 made of alumina, for example, on which a high-speed semiconductor device 20 with a cutoff frequency (f,) of about 20 GHz is mounted. In this way, the substrate 1 is
However, if necessary, a structure may be adopted in which a support stand (not shown) fixed to the bottom surface inside the container 5, for example, is provided, and the substrate 1 is fixed to this support stand. Note that, as in the conventional case, the terminals of the semiconductor device 20 and the electrodes on the substrate 1 are
The semiconductor device 20 and the external circuit are connected by using a fixing jig (not shown).

The substrate 1 is provided with a heater 6 such as a resistance heating element made of nichrome wire, for example. The heater 6 is connected to a power supply line 5 (not shown).

A pipe 12 for introducing and discharging liquid refrigerant 8 is provided near the bottom of the container 5 . The pipe 12 is connected to a floating liquid nitrogen injection container (not shown), and the height of the liquid level 9 of the refrigerant 8 in the container 5 can be adjusted by raising and lowering a float in the injection container.

The top of the container 5 is covered by a removable lid 70. As shown in the partially enlarged view of FIG. 2, a hollow transparent window 7 made of, for example, transparent quartz and evacuated inside is attached near the center of the lid 70. Further, the lid 70 is provided with a vent hole 14 for releasing the vaporized refrigerant 8. In addition.

The entire lid 70 may have a hollow structure like the transparent window 7.

The test using the low temperature test apparatus of the present invention is conducted as follows. First, the semiconductor device 20 is mounted on the substrate 1, and the cable 15 connected to a measuring device (not shown) is connected to the conversion connector 3. Next, liquid nitrogen is gradually introduced into the container 5 through the pipe 12 to raise the liquid level 9 until the semiconductor device 20 is completely immersed in the liquid nitrogen. During this time, the air inside the container 5 is filled with nitrogen gas, which is the vaporized liquid nitrogen.
It is pushed out through the ventilation hole 14 of the lid 70. Therefore, water vapor does not condense on the surface of the semiconductor device 20, the substrate 1, etc. Once the semiconductor device 20 in liquid nitrogen has stabilized at a predetermined temperature, a high frequency signal is supplied through the cable 15 to perform a predetermined test. During this time.

The semiconductor device 20 can be observed through a microscope through the transparent window 7.

When the measurement is completed, the liquid nitrogen is discharged through the pipe 12, and the liquid level 9 is lowered until the semiconductor device 20 appears.

Then, electric power is applied to the heater 6 to heat the semiconductor device 20 and the substrate 1 and raise the temperature to room temperature. This time can be shortened to about 5 and several tens of seconds by adjusting the power applied to the heater 6. When the semiconductor device 20 reaches room temperature, the lid 70 is removed and the semiconductor device 20 is replaced from the substrate 1 with another semiconductor device to be tested next. Since this exchange is performed in a nitrogen gas atmosphere, no water vapor condensation occurs. Next, the container 5 is covered with a lid 70, and liquid nitrogen is again introduced into the container 5 through the pipe 12 to conduct a test.

〔Effect of the invention〕

As is clear from the above description, the low temperature testing apparatus of the present invention provides the following effects.

(2) It is not necessary to connect and disconnect the conversion connector 3 and the cable 15 for each test, and the cable 15 can be kept in a fixed state. As a result, it is possible to obtain characteristic test results with good reproducibility because there are no connection failures, signal reflection losses, or variations in the characteristic impedance of the cable that occur in conventional test equipment.

(2) Since the semiconductor device 20 is attached to and detached from the test equipment in a nitrogen gas atmosphere, there is no surface oxidation due to water vapor condensation or current leakage, so accurate characteristic test results can be obtained.

(2) Since the semiconductor device 20 is not placed in a structure where it is blocked by the high-frequency line base 24 as in conventional test equipment, the semiconductor device 20 can be directly observed with a microscope through the transparent window 7.

(2) By enabling rapid heating by the heater 6, the time required to replace the semiconductor device 20 is shortened and testing efficiency is improved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a low-temperature test apparatus for high-speed semiconductor devices according to the present invention. FIG. 2 is a partially enlarged view of FIG. 1. FIG. 3 is a schematic structural diagram of a conventional low temperature testing device. In the figure, ■ and 21 are boards, 2 and 22 are transmission lines 3 and 23 are conversion connectors, and 5 and 25 are containers. 6 is a heater, 7 is a transparent window, and 8 is a refrigerant. 9 is the liquid level, 12 is the pipe, and 14 is the ventilation hole. 15 and 26 are cables, and 20 is a semiconductor device. 24 is a high frequency line base, and 70 is a lid. Machi Kagae Hasta Yosai illustration 2

Claims (1)

[Scope of Claims] 1) A container (5) with a heat-insulating structure filled with liquefied refrigerant; a conversion connector (3) fixed to a side wall of the container (5); (5) has one end extending inside the container (5) and the other end connected to the conversion connector (3), and the one end extending inside the container (5) is a substrate (1) on which an object to be measured is attached. a transmission line (2) connected to a transmission line (2), a heater (6) provided on the substrate (1) for heating the object to be measured, and a height of the liquid level of the refrigerant in the container (5). 1. A low-temperature testing apparatus for high-speed semiconductor devices, comprising means for introducing and discharging the refrigerant in order to change the temperature of the refrigerant. 2) The low-temperature testing apparatus for high-speed semiconductor devices according to claim 1, characterized in that a hollow transparent window (7) whose interior is evacuated is provided on the upper surface of the container (5).