JPH04286349A - Semiconductor integrated circuit test device - Google Patents

Abstract

PURPOSE:To provide a low temperature prober which is provided with a mechanism that is able to remove water attached to the surface of a wafer in a short time and enables the wafer to rise in temperature and be taken out quickly and economically. CONSTITUTION:A test chamber 1 where the electrical characteristics of a semiconductor integrated circuit are tested at a low temperature and a spare chamber 2 provided with a plasma generating mechanism are provided, moisture is removed from a wafer through a plasma cleaning treatment in the spare chamber 2 in a pretest process, an after-treatment chamber 3 where dry gas can be introduced is provided, and the wafer may be made to increase in temperature starting from a low to a room temperature in a dry gas atmosphere.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a testing device for semiconductor integrated circuits. More specifically, the present invention relates to a test device for testing the electrical characteristics of semiconductor integrated circuits in a wafer state at low temperatures, for example, down to the temperature of liquid nitrogen.

In recent years, with the demand for faster speeds of information processing systems such as computers and communication systems such as switching equipment, there has been a desire for faster speeds of semiconductor integrated circuits that constitute the systems. As one of the means to speed up semiconductor integrated circuits,
Since semiconductor integrated circuits may be operated at low temperatures such as liquid nitrogen temperature, there is an increasing need to test the electrical characteristics of semiconductor integrated circuits at low temperatures. On the other hand, in order to efficiently test semiconductor integrated circuits manufactured on a scale of several dozen on a single wafer, it is necessary to use probes directly to the input/output terminals (pads) of the semiconductor integrated circuits on the wafer. A test device (prober) that performs tests by applying

[0003] For this reason, low-temperature probers are currently used to test the electrical characteristics of semiconductor integrated circuits at low temperatures in the wafer state. Adsorbent substances, mainly water, must be removed before testing, as they prevent good contact with the pad.

[0004]Furthermore, when the wafer is taken out after being cooled to a low temperature after the test, frost adheres to the surface of the wafer. Since sophisticated semiconductor integrated circuits are sensitive to water and their characteristics deteriorate, it is advantageous to heat the wafer and remove it to prevent frost from forming.

[0005]

[Prior Art] In conventional low-temperature probers, after a wafer is placed in a test chamber, the test chamber is evacuated to a high vacuum while heating the semiconductor integrated circuit at a temperature of 100°C or less, thereby evacuating the wafer surface. Adsorbed moisture was removed. However, in this case, the test chamber is directly exposed to the atmosphere when replacing the wafer, and because the bond between the adsorbed moisture on the wafer surface and the wafer is strong, it takes several hours to exhaust, that is, to remove the adsorbed moisture. Moreover, it could not be completely removed, resulting in poor contact between the probe and the pad.

In order to raise the temperature of the wafer and take it out without forming frost, conventional low-temperature probers use a heater to heat the test chamber, and once it reaches room temperature, dry gas is introduced to cool the test chamber. A dry gas atmosphere was used. Although this method can also prevent frost from forming, it is uneconomical as it requires all the liquid nitrogen in the tank to evaporate, and it takes more than an hour to raise the temperature itself. Since the test chamber is directly exposed to the atmosphere, moisture in the atmosphere is adsorbed to the walls of the test chamber and the probe card, making it time consuming to prepare the next sample for testing.

[0007]

[Problems to be Solved by the Invention] As described above, in the conventional low-temperature prober, it takes time to remove the adsorbed moisture on the wafer, but in comparison, it is difficult to reliably remove the adsorbed moisture on the wafer. As a result, it is not possible to perform low-temperature characteristic tests of semiconductor integrated circuits reliably and quickly, and it also takes time to heat up and take out the wafer, which is uneconomical.

Therefore, the present invention is equipped with a mechanism that can reliably remove adsorbed moisture on the wafer surface in a short time, which was conventionally unreliable and time-consuming, and also enables economical heating and removal of the wafer. The purpose of the present invention is to provide a low-temperature prober that can be used quickly.

[0009]

[Means for Solving the Problems] According to the present invention, in order to solve the above problems, there is provided a test chamber 1 for testing the electrical characteristics of semiconductor integrated circuits at low temperatures, and a preliminary chamber 2 equipped with a plasma generation mechanism. There is also provided a testing apparatus for semiconductor integrated circuits, characterized in that moisture is removed by plasma cleaning in the preliminary chamber in a pre-test process.

[0010] This apparatus further includes a post-processing chamber 3 into which dry gas can be introduced, and after the test is completed, the temperature is raised from low temperature to room temperature in a dry gas atmosphere in this post-processing chamber. good.

FIG. 1 shows an example of the apparatus of the present invention. In the figure, reference numeral 1 indicates a test room, where characteristic tests of semiconductor integrated circuits are performed. 2 is a preliminary room where plasma cleaning of the wafer surface is performed before testing. 3 is a post-processing chamber in which the wafer, which has been cooled to a low temperature, is heated to room temperature. The wafers are transported in this order from the preliminary chamber 2 to the test chamber 1 and then to the post-processing chamber 3.

0012

[Operation] FIG. 2 is a detailed view of the preliminary chamber 2. As shown in the figure, the preliminary chamber 2 is equipped with an introduction system for inert gas such as argon, a high frequency power source 4 and an electrode 5 for generating plasma in the chamber, and an exhaust system for exhausting the interior of the chamber. . After the wafer 6 is transferred into the preliminary chamber 2 and the chamber is evacuated, an inert gas is introduced and a high frequency power source is used to generate a discharge and generate plasma. Ions and electrons in the plasma that have gained energy from the high-frequency electric field and the electric field within the sheath collide with the wafer. At this time, some of the neutral particles in the plasma also collide with the wafer. As a result, the adsorbed moisture on the wafer surface is scattered in the form of molecules, and the wafer surface is purified. The purpose of using an inert gas is to prevent a chemical reaction with the semiconductor integrated circuit material on the wafer. Furthermore, if the energy of the particles in the plasma that collide with the wafer is too large, it will even damage the semiconductor integrated circuit, so the discharge energy must be kept below that level. After cleaning, the wafer is transferred to test chamber 1 and tested.

FIG. 3 is a detailed view of the post-processing chamber 3. As shown in the figure, the post-processing chamber has an introduction system for drying gas such as nitrogen, and an exhaust system for exhausting the inside of the room. After the test is completed, the wafer 6 cooled to a low temperature is transferred to the post-processing chamber 3 and heated to room temperature by the heater 7. At this time, drying gas is introduced into the room to prevent frost from adhering to the wafer surface.

FIG. 4 is a detailed view of the test chamber 1. Since the test chamber 1 is not exposed to the outside air except when replacing the probe card 8, it is possible to maintain a high vacuum inside the chamber at all times.

[0015]

[Examples] Examples of the present invention will be given below to further explain the invention. After opening the first partition wall 9 and transferring the wafer to the preliminary chamber 2, the chamber is evacuated to, for example, 1×10 −5 Torr. Inert argon gas is introduced and the internal pressure is increased to, e.g.
×10 −3 Torr and discharge with a power of, for example, 100 W to create plasma. Plasma cleaning is performed for 3 minutes, for example. After this, since the adsorbed moisture on the inner wall of the preliminary chamber 2 and the surface of the wafer 6 has been removed, the degree of vacuum is better than the initial 1 x 10-5 Torr, and is 3.
~5×10 −6 Torr is reached. If this is not achieved, the process of introducing gas is repeated again. FIG. 5 is a flowchart of the cleaning process.

After the cleaning process, the second partition wall 10 is opened and the wafer 6 is transferred to the test chamber 1 having a pressure of about 3×10 −6 Torr. After the test, open the third partition 11 and
The sample is transported to the post-treatment chamber 3 at a pressure of ×10 −3 Torr. Nitrogen drying gas is introduced, and the wafer 6 is heated by the heater 7 while being returned to room temperature. When the temperature reaches room temperature, the fourth partition wall 12 is opened, the wafer is taken out, and the wafer is stored in a wafer storage box.

[0017]

[Effects of the Invention] As explained above, according to the present invention, it is possible to reliably remove adsorbed moisture, raise the temperature of the wafer, and take it out in a short time, which is necessary before testing the low-temperature characteristics of semiconductor integrated circuits. This greatly contributes to improving the reliability and throughput of low-temperature characteristic testing of semiconductor integrated circuits.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the device of the present invention.

2 is a detailed view of the preliminary chamber of the device of FIG. 1; FIG.

3 is a detailed view of the post-treatment chamber of the apparatus of FIG. 1; FIG.

4 is a detailed view of the test chamber of the apparatus of FIG. 1; FIG.

FIG. 5 is a flowchart of cleaning processing in the example.

[Explanation of symbols]

1...Examination room 2...Preliminary room 3...Post-processing room 4...High frequency power supply 5...Electrode 6...Wafer 7...Heater 8...Probe card 9...First bulkhead 10...Second partition wall 11...Third bulkhead 12...Fourth bulkhead

Claims (2)

[Claims] Claim 1: A test chamber (1) for testing the electrical characteristics of semiconductor integrated circuits at low temperatures; and a preliminary chamber (2) equipped with a plasma generation mechanism; A testing device for semiconductor integrated circuits, characterized in that moisture is removed by plasma cleaning treatment. [Claim 2] A test chamber (1) for testing the electrical characteristics of semiconductor integrated circuits at low temperatures, a preliminary chamber (2) equipped with a plasma generation mechanism, and a post-processing chamber (3) into which dry gas can be introduced.
In the pre-test step, moisture is removed by plasma cleaning in the preliminary chamber, and after the test, the temperature is raised from low temperature to room temperature in a dry gas atmosphere in the post-treatment chamber. A test device for semiconductor integrated circuits, characterized in that: