JPS62190844A - Low temperature prober - Google Patents

Abstract

PURPOSE:To enhance the reliability of a semiconductor device by disposing a probe head in an atmosphere of gas having low critical temperature to perform a low temperature probe test without damaging the element characteristics of the device in a low temperature operation. CONSTITUTION:Since a cryohead is a coolant which can be cooled to 40 deg.K in a head section of a cryopump, it is used as a stage 12, and a probe card 13 is positioned while visually observing in a microscope 15 by utilizing an infrared light source 14. The infrared light does not disturb a low temperature operation. Then, a housing 16 is evacuated in vacuum by a vacuum pump 18, and helium gas is circulated in the housing 15 by other compressor 17. When a probe test is executed in this manner, the characteristics of a measuring element is not, since the helium is not dew-condensed, deteriorated. Since it is not in vacuum, a manipulator can be readily regulated, a wafer can be attracted to the low temperature stage, and the probe test can be performed while automatically moving a manipulator stage and a probe card stage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] A prober for low-temperature operation measurement has a probe head placed in a gas with a low waterfront temperature that is low and does not condense.

[Industrial application fields] The present invention relates to a low temperature prober (probe testing device).

Recently, high-speed operation elements have been required for semiconductor devices due to the demands of computers, etc., and new elements are being developed that actively consider not only operation at room temperature but also operation at low temperatures. For example, high electron mobility transistor (HEMT:
High Electron Mobility Tr
.

) is an example.

For such semiconductor devices operated at low temperatures, it is desirable to perform a probe test at a low temperature, and consideration must be given so as not to destroy the elements.

[Prior Art] Conventionally, in semiconductor devices such as ICs, a large number of elements are formed on a wafer, and before the wafer is divided into individual chips, a probe is brought into contact with the wafer to detect the electricity of those elements. This is called a wafer probe test, and the window measurement device is called a blow μ.

This is because if a probe test is conducted in advance in the wafer state, the number of man-hours for assembling a defective chip into a package and the materials used for the package can be saved.

Figure 2 shows a schematic diagram of a conventional low-temperature blow μ test head, in which 1 is a wafer, 2 is a stage, 3 is a probe, 4 is a visible light source, and 5 is a microscope 6, which is a box made of heat-retaining material. be.

For example, when performing a probe test at 77°K (liquid nitrogen temperature), liquid nitrogen LN2 is stored inside the box 6. Then, the probe is positioned by moving the manipulator while visually observing it through a microscope through the window 7 provided at the top of the box, and after adjusting the position, a probe test is performed. In addition to the test head described above, the blow μ is equipped with a computer, but this is not shown. In addition, recently, in order to avoid the complexity of adjusting each of a plurality of probes, a probe card on which already aligned probes are planted is often used.

[Problems to be Solved by the Invention] By the way, when a probe test is performed at a low temperature as described above, there is a troublesome problem that dew condensation occurs near the wafer 1 and the probe 3. Condensation occurs not only from moisture, but also from liquid nitrogen. If you test by passing current under such conditions, an abnormal current bus will occur, causing problems such as destruction of the insulating film, and affecting the operating characteristics of the measuring element. deteriorates.

For this reason, a method has been devised in which the inside of the box 6 is vacuumed to perform a probe test, but heat conduction is poor in a vacuum (
However, the disadvantage is that the wafer is difficult to cool.

On the other hand, there is also a method of separating and assembling chips, cooling them to a low temperature, and measuring their low-temperature operating characteristics without performing a probe test, but this method requires a lot of man-hours and was previously expensive. Become.

The present invention solves these drawbacks and proposes a low-temperature blow μ that can perform probe tests at low temperatures with high reliability.

[Means for Solving the Problems] The object is achieved by a low-temperature blow μ in which the probe head is placed in an atmosphere of a gas with a low critical temperature, such as helium (He).

[Function] That is, the present invention performs a probe test in a gas atmosphere with a low critical temperature that does not cause dew condensation.

[Example code] Hereinafter, one embodiment will be described in detail with reference to the drawings.

FIG. 1 shows a schematic diagram of a low-temperature blow μ test head according to the present invention, and numeral 11 indicates a wafer.

12 is a stage consisting of a cryohead, 13 is a probe card, 14 is an infrared light source, and 15 is an infrared microscope.

16 is a box made of a heat insulating material, 17 is a helium compressor, 18 is a vacuum pump, and 19 is a transmission window.

The cryohead is the head part of the cryopump.
Since it is a cooling body capable of cooling up to 40°K, it is used for the stage 13. Then, the probe card 13 is aligned while being visually observed with a microscope 15 using the infrared light source 14. This infrared light does not harm low temperature operation. Next, the inside of the box 16 is vacuumed by the vacuum pump 18, and the other compressor 17 circulates the lyhelium gas inside the box 16. The reason for using the compressor 17 is to avoid consuming a large amount of helium gas.

If a probe test is performed with this configuration, helium does not condense, so the characteristics of the measuring element will not deteriorate. Furthermore, switching between room temperature and low temperature becomes easy.

Moreover, since it is not in a vacuum, it is easy to adjust the manipulator, the wafer can be attracted to the low temperature stage, and probe tests can be performed while automatically moving the manipulator stage and probe card stage.

That is, it is also possible to configure it as an autoprober.

[Effects of the Invention] As is clear from the above explanation, according to the present invention, a low temperature probe test can be performed without destroying the element characteristics of a semiconductor device operating at low temperature, and the reliability of the semiconductor device can be improved. It is something that can be achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a low-temperature blow μ test head according to the present invention, and FIG. 2 is a schematic diagram of a conventional low-temperature blow μ test head. In the figure,

Claims (2)

[Claims] (1) A low-temperature prober that measures device characteristics by bringing a probe into contact with a semiconductor device on a wafer at a low temperature below room temperature, characterized in that the probe head is placed in a gas atmosphere with a low critical temperature. Prober for use. (2) The low temperature prober according to claim 1, wherein the gas having a low critical temperature is helium.