JPH04357848A - Prober for semiconductor wafer - Google Patents

Abstract

PURPOSE:To ensure the contact of a low-temperature wafer probe with a warped wafer. CONSTITUTION:A spring member 11 for urging a wafer 5 against a wafer stage 2 is provided near a probe 7 that is in contact with the cooled wafer on the stage. If the wafer is warped with an upward curve, the spring member serves to correct the warpage. Therefore, the probe can touch the wafer maintained horizontal to the stage, so that reliable contact is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prober for semiconductor wafers used for measuring or testing the electrical characteristics of semiconductor wafers at low temperatures.

0002

[Prior Art] Conventionally, semiconductor wafer probers for measuring the electrical characteristics of semiconductor wafers have been used to measure the electrical characteristics of semiconductor wafers.
There is a structure in which the wafer (hereinafter simply referred to as a wafer) is cooled and a probe is pressed against the measurement surface of the wafer. This type of prober for semiconductor wafers will be explained with reference to FIG.

FIG. 3 is a sectional view of a conventional wafer prober for low temperature use. In the figure, 1 is a vacuum chamber, and 2 is a wafer stage mounted in the vacuum chamber 1 via an XY moving mechanism 3. A window 4 made of a transparent material is provided at the top of the vacuum chamber 1 so that the inside can be viewed. The XY moving mechanism 3 is configured to be able to move the wafer stage 2 in parallel in the X direction and the Y direction.

A wafer 5 is placed on the wafer stage 2 and fixed to the wafer stage 2 by a wafer fixing jig 6 attached to the wafer stage 2. Reference numeral 7 denotes a probe needle as a probe for contacting the upper surface (measurement surface) of the wafer 5 to obtain electrical continuity. It protrudes downward. Further, this probe card 8 is supported by a probe card fixing base 9 fixed within the vacuum chamber 1. Reference numeral 10 denotes a refrigerator for cooling the wafer 5, and the refrigerator 10 is configured to cool the wafer stage 2 and the wafer 5 by conduction.

Next, the operation of the conventional semiconductor wafer prober constructed as described above will be explained. To measure the electrical characteristics of the wafer 5, the wafer 5 is first placed on the wafer stage 2 and fixed using a wafer fixing jig 6 so as not to move in the X-Y direction. Next, the inside of the vacuum chamber 1 is evacuated, and then the wafer stage 2 and wafer 5 are cooled by the refrigerator 10. Then, the wafer stage 2 and wafer 5 are moved by the X-Y moving mechanism 3 to position the portion to be measured directly below the probe needle 7. After that, wafer stage 2 and wafer 5
is moved upward, and the wafer 5 is brought into contact with the probe needle 7 by pressing it against it. In this way, electrical continuity is established and measurement is performed.

[0006]

[Problem to be Solved by the Invention] However, since the conventional low-temperature wafer prober is configured as described above,
As shown in FIG. 3, when trying to establish electrical continuity with the wafer 5 whose measurement surface side is convex, the wafer 5 and the probe needle 7
There was a problem that the parallelism between the probe needles 7 and the wafer 5 was poor, and some of the probe needles 7 did not come into contact with the wafer 5, as shown in FIG. Note that FIG. 4 is an enlarged cross-sectional view showing a contact portion between a probe needle and a wafer in a conventional low-temperature wafer prober.

[0007]

[Means for Solving the Problems] A prober for semiconductor wafers according to the present invention is provided with a spring member near the probe tip for pressing the semiconductor wafer against the wafer stage.

[0008]

[Operation] When the semiconductor wafer is warped in an upwardly convex manner, the spring member corrects the warp of the semiconductor wafer.

[0009]

[Embodiment] An embodiment of the present invention will be explained in detail below with reference to FIG. FIG. 1 is a sectional view of a prober for semiconductor wafers according to the present invention, which shows a state in which a wafer is pressed against a probe needle. In FIG. 1, reference numeral 11 denotes a spring member for pressing the wafer 5 against the wafer stage 2. This spring member 11 is formed by bending a bar-shaped spring material, and is fixed to the lower part of the probe card fixing table 9. Further, this spring member 11 protrudes downward from the probe card fixing base 9 and extends in the horizontal direction so that its tip is located next to the tip of the probe needle 7.

In the semiconductor wafer prober equipped with the spring member 11 as described above, the wafer 5 is mounted on the wafer stage 2 in the same manner as in the prior art and cooled in vacuum. After cooling, when the wafer 5 is raised together with the wafer stage 2, the spring member 11 comes into contact with the wafer 5 if the wafer 5 is curved upward. When the wafer 5 and the wafer stage 2 are further raised in this state, the wafer 5 is biased by the spring member 11 to remove the warpage and is pressed against the wafer stage 2. That is, the probe needle 7 comes into contact with the wafer 5 which is parallel to the wafer mounting surface of the wafer stage 2, and is electrically connected to the wafer 5 in this state.

Therefore, when the wafer 5 is warped in an upwardly convex manner, the spring member 11 corrects the warp of the wafer 5.

Although this embodiment shows an example in which the spring member is shaped like a rod, the present invention is not limited to such a limitation, and for example, a helical spring can be used as shown in FIG. . FIG. 2 is a cross-sectional view showing another embodiment in which the spring member is composed of a helical spring. In this figure, the same or equivalent members as those explained in FIG. 1 are given the same reference numerals and detailed explanations are omitted. do. In FIG. 2, 21 is a helical spring constituting a spring member. This helical spring 21 is arranged at a position adjacent to the probe needle 7 on the wafer fixing table 9 . Even if the helical spring 21 is used in this manner, the same effect as in the embodiment described above can be obtained.

[0013]

Effects of the Invention As explained above, the semiconductor wafer prober according to the present invention is provided with a spring member near the probe that presses the semiconductor wafer against the wafer stage, so that the semiconductor wafer is warped in an upwardly convex manner. The spring member corrects the warpage of the semiconductor wafer when the semiconductor wafer is bent. Therefore, since the probe contacts the semiconductor wafer in a state parallel to the wafer stage, conduction can be ensured. Therefore, reliability when the probe contacts the semiconductor wafer can be improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a prober for semiconductor wafers according to the present invention.

FIG. 2 is a sectional view showing another embodiment in which the spring member is formed of a helical spring.

FIG. 3 is a cross-sectional view of a conventional low-temperature wafer prober.

FIG. 4 is an enlarged cross-sectional view showing a contact portion between a probe needle and a wafer in a conventional low-temperature wafer prober.

[Explanation of symbols]

2 Wafer stage 5 Semiconductor wafer 7 Probe needle 10 Refrigerator 11 Spring member 21 Helical spring

Claims (1)

[Claims] 1. A semiconductor wafer prober in which a semiconductor wafer is cooled on a wafer stage and a probe is brought into contact with the semiconductor wafer in this state, and a spring member is provided near the probe to press the semiconductor wafer against the wafer stage. A prober for semiconductor wafers characterized by: