JP3251205B2 - Wafer measurement method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a wafer at a wafer stage by using a tester to determine whether a product is good or defective, and more particularly to a method for suppressing a rise in the temperature of a probe card when measuring a high temperature of a wafer. .

[0002]

2. Description of the Related Art In order to sell a semiconductor as a single wafer, it is necessary to guarantee temperature characteristics at a wafer level.
Therefore, in wafer measurement, the temperature of the wafer stage can be controlled so that inspection can be performed not only at a high temperature but also at a low temperature. To perform wafer measurement, interpose a probe card between the wafer and the test head,
The probe needle of the probe card is brought into contact with the wafer, and the wafer is connected to the test head.

[0003]

When the wafer itself is heated and the temperature of the wafer is measured at a high temperature, the heat of the heated wafer is transmitted to the probe needles to heat the probe card. The amount of heating varies depending on conditions such as the temperature difference between the front and back surfaces of the probe card and the type of the probe card. However, this heating causes the probe card to be warped. The probe card is extremely elaborately made for each die of the wafer, and the needle is precisely aligned with the wafer.If the probe card warps, the flatness of the probe needle tip is increased, Misalignment, poor contact may occur, and in some cases, the contact pressure may increase and damage the wafer.

[0004] It is an object of the present invention to provide a wafer measuring method and apparatus which solves the above-mentioned problems of the prior art and prevents deformation of the wafer even at the time of high temperature measurement.

[0005]

According to the wafer measuring method of the present invention, a probe card for electrically connecting the wafer to a test head is cooled when measuring the high temperature of the wafer. Even if the temperature of the heated wafer is transmitted to the probe card during the high temperature measurement of the wafer, the probe card is cooled, so that the probe card is not deformed by the heat.

Further, according to the wafer measuring method of the present invention, a wafer mounted on a prober stage is brought into contact with a probe needle of a probe card to electrically connect the wafer and a test head, thereby electrically connecting the wafer in a high-temperature environment. Measure properties
In this method, a cooling gas is blown to a probe card during high-temperature measurement of a wafer. During the high temperature measurement of the wafer, even if the heat of the wafer, which has become hot due to the probe needle, is transmitted to the probe card, the cooling gas is blown to the probe card to cool the probe card. No deformation.

[0007] The wafer measuring apparatus of the present invention further comprises a test head connected to the wafer via a probe needle of a probe card for performing a measurement of the wafer, and a gas supply system for blowing a cooling gas to the probe card. It is. The gas supply system may be mounted on the prober side or on the test head side.However, if it is mounted on the test head side, the cooling gas can be blown from directly above the probe card, making uniform cooling possible. And the cooling efficiency can be increased.

Further, when a dryer is provided in the gas supply system, when air is blown from the gas supply system, moisture contained in the air is removed by the dryer.
Even when air is blown, moisture in the air does not adhere to the probe card.

[0009]

Embodiments of the present invention will be described below. FIG. 1 shows a wafer measuring device. The wafer measuring apparatus includes a prober 2 for performing an electrical test on a wafer and a test head 1 for determining whether the electrical test is good or bad.

The prober 2 has a probe 8
To allow the electrical test of the wafer 8 by the test head 1 connected via the probe needle 7.
On the prober 2 side, the wafer 8 is held in order to hold the wafer 8 and to measure the electrical characteristics in a high temperature environment.
A stage 9 having a heater 17 for heating the wafer, a probe card 6 in which conductive probe needles 7 for connecting the wafer 8 to the test head 1 on the prober 2 side,
A pogo pin ring 5 for connecting the wafer board 4 and the probe card 6 is provided. The pogo pin ring 5 has a ring shape with a hole at the center, and a pogo pin 10 electrically connected to the wafer board 4 at an upper peripheral portion, and a pogo pin 10 electrically connected to the probe card 6 at a lower peripheral portion.
The wafer board 4 and the probe card 6 are connected by the spring contact of the pogo pins 10.

The test head 1 includes a power supply applied to the wafer 8, a signal output unit to the wafer, a signal input unit from the wafer, and the like. The test head 1 is connected to the wafer 8 via the probe card 6 and evaluates the wafer 8. . On the test head 1 side, a wafer board 4 that is electrically connected to the pogo pins 10 of the pogo pin ring 5 and a plurality of terminals for connecting the wafer 8 to various measurement circuits in the test head 1 are tested. A performance board 3 derived from the head 1 is attached.

A gas supply system 13 for blowing a cooling gas, for example, air, onto the surface of the probe card 6 while measuring the high temperature of the wafer 8 is attached to the test head 1 side. The gas supply system 13 is provided with a dryer 15 for removing moisture contained in the air. The air blown out from the gas supply system 13 is drawn from the factory by the tube 12. The gas supply system 13 includes a nozzle 11 projecting downward from the wafer board 4 with the outlet facing the surface of the probe card 6,
It comprises a tube 12 connected to the nozzle 11 and guided to the factory through the inside of the test head 1, a dryer 15 provided in the middle of the flexible tube 12, and a flow control valve 16 for controlling the flow rate of air. Although the number of the nozzles 11 is not particularly limited, a plurality of nozzles 11 are provided at intervals so that the entire surface of the probe card 6 can be uniformly cooled. The air sent from one tube 12 branches on the way in the manifold 18 and is supplied to each nozzle 11. The test head 1 goes up and down,
Since it rotates, the tube 12 is preferably a flexible tube.

The performance board 3 and the wafer board 4 are attached to the test head 1 and move together with the test head 1. Therefore, the nozzle 11 attached to the wafer board 4 also moves together with the test head 1.

Now, in order to measure a wafer in the above-described configuration, as shown in FIG. 2, the test head 1 is lowered toward the prober 2 and the wafer board 4 attached to the lower part of the test head 1 is measured. Pogo pin ring 5
It is pressed against the upper pogo pin 10. As a result, the pogo pins 10 under the pogo pin ring 5 press the probe card 6 into pressure, and the probe needles 7 of the probe card 6 come into contact with the wafer 8. At this time, the nozzle 11 protruding from the wafer board 4 is inserted into the center hole of the pogo pin ring 5,
The outlet of the nozzle 11 approaches the probe card 6 and comes to the cooling position.

At the time of measuring the high temperature of the wafer, the flow rate of the air supplied from the factory through the gas supply system 13 is controlled by the flow control valve 16, and the moisture in the air is removed by the dryer 15. It blows out from the attached nozzle 11. This blowing continues during the high temperature measurement. The air blown out from the nozzle 11 is blown to the surface of the probe card 6, and the probe needle 7
To dissipate the heat of the wafer transmitted to the probe card 6 via the substrate, thereby cooling the probe card 6.

In particular, the test head 1 covers the prober 2 with the nozzle 11 for blowing air to the probe card 6.
Attached to the wafer board 4 on the side
Since the air is blown from directly above the probe card 6, the probe card 6 can be cooled effectively and uniformly. Therefore, the warp of the probe card 6 due to heat can be eliminated, and the air is continuously blown, so that the flatness of the probe needle tip does not change during high temperature measurement, and the probe needle 7 The occurrence of poor contact and the increase in the contact pressure will not damage the wafer 8.
Further, since air from which moisture has been removed is blown by passing through a dryer, short-circuit failure between probe needles due to moisture does not occur.

In the above embodiment, air is blown from above the probe card, but air may be blown from the back of the probe card or from the side. To spray from the back or side of the probe card, a nozzle may be attached to the probe side. Further, the amount of air blown from the nozzles and the positional relationship of the nozzles with respect to the probe card can be determined by the number of probe needles, the probe card shape, the probe card size, the number of nozzles, and the like. The cooling gas is not limited to air but may be an inert gas or the like. Further, a method other than the gas blowing may be used for cooling the probe card.

[0018]

According to the method of the present invention, the probe card is cooled to prevent the probe card from being deformed by heat during the high temperature measurement of the wafer, so that the contact failure of the probe needle occurs or the contact pressure increases. The wafer is not damaged. According to the apparatus of the present invention, since the gas supply system is provided in the test head, the cooling gas can be blown from directly above the probe card, and the probe card can be uniformly and effectively cooled.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a wafer measurement device according to an embodiment.

FIG. 2 is a schematic diagram of a wafer measurement device at the time of temperature measurement according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Test head 2 Prober 6 Probe card 7 Probe needle 8 Wafer 9 Stage 11 Nozzle 13 Gas supply system 15 Dryer 17 Heater

Claims (3)

(57) [Claims] A wafer placed on a stage of a prober is brought into contact with a probe needle of a probe card to electrically connect the wafer and a test head to each other in a high temperature environment of the wafer.
A method for measuring electrical characteristics of a wafer, wherein a cooling gas is blown from directly above the surface of the probe card during high temperature measurement of the wafer. 2. A wafer measuring apparatus comprising: a prober for performing an electrical test on a wafer; and a test head for determining whether the electrical test is good or bad, the prober comprising: a stage for holding and heating the wafer; A probe card having a probe needle for contacting a wafer held on a stage, a pogo pin ring having a pogo pin for pressing the probe card at a lower peripheral portion, and having a pogo pin for pressing the wafer board at an upper peripheral portion and having a hole in the center thereof; And the test head is in pressure contact with a pogo pin at a peripheral upper portion of the pogo pin ring,
A wafer board for electrically connecting the wafer and the test head; and a nozzle protruding downward from the wafer board,
A gas supply system, wherein when the test head is lowered to the prober, the nozzle is inserted into a central hole of the pogo pin ring, and a cooling gas is blown from directly above the surface of the probe card. . 3. The wafer measuring apparatus according to claim 2, wherein a dryer is provided in the gas supply system.