JP2879282B2 - Probe device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe device.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, after an IC chip is completed in a wafer, it is divided into individual chips and packaged. Before a package, however, a probe device is used to eliminate defective chips. An electrical measurement called a probe test is performed on each chip in the wafer.

In this probe apparatus, conventionally, a probe needle arranged corresponding to an electrode pad arrangement of IC chips in a wafer is provided above a wafer holding table movable in, for example, X, Y, Z, and θ directions. With the probe card provided, the wafer holder is moved and the electrode pad of the IC chip in the wafer is aligned with the probe needle, and then the probe needle and the electrode pad are brought into contact, and the electrode pad is moved to the probe needle and pogo pin. Is electrically connected to the test head via an insert ring including the above, and the quality of the IC chip is determined by performing electrical measurement using, for example, a high frequency corresponding to the operating speed of the IC.

In recent years, the wafer is heated to, for example, a high temperature of 60 ° C. to 125 ° C. by a heater provided on a wafer holder before being divided into chips, and the IC chips on the wafer are kept at a high temperature. A method of performing the above-described electrical measurement has also been implemented.

When the measurement is performed in such a high temperature state, the probe card thermally expands due to radiant heat from the wafer and heat conduction from the needle tip, and the probe needle itself also expands. The needle tip level (the height position of the needle tip of the probe needle) of the arranged probe needles becomes lower than at room temperature. Therefore, if the probe needle is brought into contact with the electrode pad before the temperature of the probe card stabilizes with respect to the temperature of the heated wafer, that is, before the stylus level of the probe needle stabilizes, The probe card is thermally expanded by the heat transfer, and the tip of the probe is pressed against the wafer surface with a strong force.

Here, since the probe needle extends obliquely from the probe card, when the needle tip is pressed against the wafer surface with a strong force, the probe needle is bent and forcibly deformed, thereby damaging the probe needle. There is a possibility that the tip of the probe needle slides laterally and deviates from the measurement area of the electrode pad, resulting in measurement failure. Also,
IC chips may be damaged due to excessive overdrive (biting of probe needles into the wafer surface).
On the other hand, if probing is performed with the height of the wafer holder lowered and the contact point set low to avoid excessive overdrive, the probe card cools down and shrinks when replacing the wafer, and the Will not reach.

Therefore, conventionally, (1) before measurement, for example, a probe card is brought into contact with a temperature control plate set at the same temperature as the wafer before the probe needle reaches the same temperature as the wafer. A method in which the probe card is sufficiently heated, and thereafter, the operator adjusts the height of the wafer holding table while watching the probe needles and the electrode pads with a TV camera or the like, and makes the probe needles and the wafer come into contact with each other, (2) ) The wafer is positioned immediately below the tip of the probe needle, and the probe card is sufficiently heated by radiant heat from the wafer. Then, the operator looks at the probe needle and the electrode pad with a TV camera or the like, and raises the height of the wafer holder. (3) Raise the wafer holder to bring the probe needle into contact with the electrode pad, and then adjust the probe needle. The wafer holder is lowered while maintaining a uniform contact state between the probe needle and the electrode pad based on the operator's experience or the variation data collected in advance so as to respond to the variation caused by the heat at the previous level. A method of measuring by letting it run has been adopted.

[0008]

However, the method using the temperature control plate as described in (1) above may cause damage to the probe needle, and the method described in (2) above may cause the wafer to be stuck at the probe tip. The method of preheating the probe card by radiant heat from the wafer by positioning the wafer holder just below the height of the wafer holding table is set so that the electrode pad is below the needle tip level when the needle tip level is stabilized. Therefore, it is difficult to set the height of the wafer holder, and there is a problem that it takes a considerably long time until the temperature of the probe card is stabilized.

Further, the method of lowering the wafer holder by the operation of the operator so as to cope with the fluctuation due to the heat at the tip of the probe needle as described in the above (3) requires considerable skill. Had to gain experience, and overdrive was not always appropriate because of the empirical method. Further, there is a problem that it is difficult to cope with automation of the probing process because an operator is involved in any of the above-described measurement methods.

The present invention has been made under such circumstances, and an object of the present invention is to always make a contact pressure of a probe tip of a probe needle against a surface of an object to be inspected at an appropriate level. It is to provide a probe device.

[0011]

According to the first aspect of the present invention, a high temperature
In a probe device for performing electrical measurement by bringing a plurality of probe needles arranged on a probe card into contact with an electrode pad of a test object whose temperature has been adjusted to a temperature, the probe needle is brought into contact with the electrode pad of the test object. A control unit is provided for controlling the relative position of the object to be inspected with respect to the probe card to make contact with the probe card based on data indicating the height position of the needle tip when heated .

[0012]

After the temperature of a conductive plate of the same shape as that of an object to be inspected made of, for example, aluminum is adjusted to a predetermined temperature, the probe needle is intermittently brought into contact with the probe and the current flowing between the probe needle and the conductive plate is reduced. Monitors and detects the level of the conductive plate when the current is turned on, that is, the level of the tip of the probe needle. This allows time-dependent changes in the height position of the needle tip when the temperature of the probe needle changes due to contact with the test object. Create data. Then, after the test object is actually brought into contact with the probe needle, the upper surface level of the test object is controlled based on this data. Therefore, measurement can be performed with an appropriate overdrive.

[0013]

FIG. 1 is an explanatory view for explaining a main part of a probe device according to an embodiment of the present invention, and FIG. 2 is a vertical sectional side view showing an entire configuration of the probe device according to the embodiment. In this embodiment, a test object holding table, for example, a wafer holding table 2 is installed in a housing 1 which forms an exterior part of the probe device main body. A heating unit (not shown) for heating the wafer W to a predetermined temperature, for example, 60 ° C. to 125 ° C., for example, a heater is provided.

Further, in this example, the wafer holding table 2 is made of a metal material, and is electrically connected to a current monitoring unit 2a for detecting whether or not a current is flowing therethrough. Furthermore,
The wafer holder 2 is supported by a rotation mechanism 21 provided with a motor (not shown) for rotating the wafer holder 2 around a vertical axis.
For example, a lifting mechanism 22 provided with a screw mechanism and a motor (not shown) for raising and lowering the wafer 1 (that is, raising and lowering the wafer holding table 2) is provided.

The motor of the elevating mechanism 22 is combined with a level detecting part 22a composed of an encoder, a pulse counter and the like for detecting the elevating position of the screw mechanism.

An X-direction moving mechanism 23 for moving the wafer holder 2 in the X and Y directions below the elevating mechanism 22.
And a Y-direction moving mechanism 24.

A probe card 3 having a viewing window 31 at the center is disposed above the wafer holder 2 so as to face the wafer holder 2. Probe card 3
Probe needles 4 extending diagonally downward from the left and right sides of the viewing window 31 toward the center of the viewing window 31 are provided on the left and right sides so that, for example, ten electrode pads arranged in a line can be simultaneously measured on the wafer W. A total of 200 pieces are arranged in 10 pieces. The probe card 3 is connected to the test head 3 via an insert ring 32 including a pogo pin 33 and the like.
4 is electrically connected.

Further, the probe apparatus according to the present embodiment includes a data creating section 5 for creating prediction data of a temporal change of the needle tip level when the probe needle 4 is heated, and a wafer holding table based on the data. 2 is provided with a control unit 6 for controlling the height position.

The data creation unit 5 has a function of taking in signals from the current monitoring unit 2a and the level detection unit 22a and writing the prediction data into the memory 51. A conductive plate having the same shape as W, for example, an aluminum plate is placed, and the aluminum plate is brought into contact with the probe needle 4 to heat the probe needle 4. When the conductive plate and the probe needle 4 are separated, the conductive plate is placed on the conductive plate. Although the current does not flow, the current flows from the tip of the needle when it comes into contact, so that ON / OFF of this current is detected by the current monitoring unit 2a, and the angular position of the motor of the elevating mechanism 22 at that time, that is, the probe needle 4 This is performed by detecting the needle point level.

The controller 6 places the wafer W, which is an object to be inspected, on the wafer holder 2 and gives a control signal to the elevating mechanism 22 based on the data in the memory 51, thereby controlling the height of the wafer W. It has a function to control the position.

Next, the operation of the above embodiment will be described with reference to FIG. First, the heating means of the wafer holder 2 is set to O
N, a conductive plate made of, for example, an aluminum plate having the same shape as the wafer W to be inspected is placed on the wafer holder 2, and the wafer holder 2 is raised to bring the probe needle 4 into contact with the conductive plate. Let it. As a result, the probe needle 4 is heated and extended, and the needle tip level starts to decrease. However, by intermittently contacting the conductive plate with the probe needle 4, the needle tip level is stored in the memory 51 as described above. Predictive data of the temporal change is created.

FIGS. 3A and 3B are characteristic diagrams showing the relationship between the tip level of the probe needle 4 and the elapsed time, respectively, and the relationship between the surface level of the wafer W on the wafer holder 2 and the elapsed time. FIG. 4 is a characteristic diagram illustrating a relationship. Since the aluminum plate and the wafer W have the same shape, the surface level of the aluminum plate is also described as the surface level of the wafer W. The process of detecting the temporal change of the tip level using the aluminum plate corresponds to the region indicated by A in FIG. 3A, and the data in this region A is obtained from the data at the surface level of the wafer W. This is the predicted needle-point level data (data in the memory 51). 3B is a surface level of the wafer W, and is actually represented in a stepped shape because the aluminum plate and the probe needle 4 are intermittently contacted.

[0023] Then, tip level 3 (a) and (b) medium Z ₀ is (deals with just the heated aluminum plate into contact with the probe needles 4 as room temperature) when the probe card 3 is at room temperature in and, Z ₂ is the tip level when the probe card 3 is sufficiently heated needle point temperature stabilized by heat transfer from the aluminum plate (wafer W). The level difference shown in FIG. 3 (b) Medium Z ₂ and Z _3, regardless of the thickness of the wafer, a Z-direction avoidable distance to move during wafer measurement to the next chip. The horizontal axis (time axis) in FIGS. 3A and 3B is represented on the same scale.

Next, after the data is created, the wafer holding table 2 is lowered to a predetermined level, the wafer W to be inspected is replaced with a conductive plate by a transfer mechanism (not shown), and the wafer W is placed on the wafer holding table 2. upper surface level of the wafer W after the alignment raises the wafer holder 2 so that the Z _2. During the replacement operation, the probe card 3 is cooled and its temperature is lowered. Therefore, as shown in the area B of FIG. 3A, the probe tip level is at a position (Z ₁ ) higher than Z ₂ , and therefore the wafer W after first raised at a high speed until Z ₂ is contacted to the probe needles 4 gently increased. This contact can be detected by, for example, a touch sensor or the like, and the tip level (Z _{1 in} this example) of the probe needle 4 can be known from the rotation angle of the motor at that time. Although the needle tip actually cuts into the surface of the wafer W by a predetermined overdrive amount, for convenience of explanation, the description will be made assuming that the surface of the wafer W and the needle tip level are at the same height position.

Further, after the probe needle comes into contact with the wafer W, the temperature of the probe card 3 rises due to the heat transfer from the wafer W, so that the probe card 3 has already been formed as shown by the C region in FIGS. 3 (a) and 3 (b). data of the based on the data in the memory 51 in the memory 51 taken for example the Z ₁ and Z ₂ in the a region - on the basis of the data, the wafer W surface along the connecting tie or stepwise by a curve line downward the control unit 6 so as to provide a control signal to the lifting mechanism 22, the wafer holder 2 is lowered while the needle point level is brought into contact with probes 4 and the electrode pads until Z _2, then electrical measurement Start. The area indicated by D in FIGS. 3 (a) and 3 (b) indicates that after the measurement of a certain IC chip (or IC chip row) on the wafer W is completed, another IC chip (or IC chip row) continues. Shows the needle tip level and the upper surface level of the wafer W in the process of inspecting the wafer W. In this case, when the wafer holding table 2 is "step-moved", the wafer once moves downward and moves to the next step, as shown in FIG. 3B. In order to indicate "cooling of the needle" corresponding to this avoidance operation, the needle point level in the area D in FIG. 3A is slightly increased. Actually, this step travel time is
Since the time is less than one second, the rise in the needle point level is very small. When the measurement is performed while the wafer W is subsequently replaced, the measurement is performed in the same pattern as the patterns shown in the areas B to D in FIGS. 3A and 3B.

According to such an embodiment, the probe needle 4
The time data of the height of the stylus level after the wafer is brought into contact with the wafer W and heated is prepared in advance, and the control unit 6 controls the height position of the upper surface level of the wafer W based on this data. Therefore, there is no possibility that the probe tip is pressed against the wafer W with a strong force and the probe needle 4 bends and is damaged, or the probe tip of the probe needle 4 slides off the electrode pad to cause a measurement failure. Absent. In addition, there is no danger of the IC chip being damaged by excessive overdrive, and the preheating time of the probe card 3 can be significantly reduced as compared with the method in which the wafer is kept waiting just below the probe needle. Further, since the probing process is automated, the throughput can be improved.

In the above description, according to the present invention, as shown in FIG. 4, for example, the probe needle 4 is preliminarily heated to prepare data indicating the relationship between the temperature of the probe needle 4 and the needle tip level, and Based on this, the surface level of the wafer W (wafer holding table 2) may be controlled. That is, in FIG. 4, reference numeral 3a denotes a temperature detecting unit such as a thermocouple for detecting the temperature of the probe card 3. In this embodiment, a needle point level is detected in advance by using an aluminum plate similarly to the above-described embodiment. However, the detection signal from the temperature detection unit 3a is taken in to create data indicating the relationship between the temperature and the needlepoint level. At the time of measuring the wafer W, the control unit 6 sets the height position of the wafer holding table 2 so as to correspond to the stylus level of the temperature at that time based on the detection signal from the temperature detection unit 3a and the data in the memory 51. Controlling.

In this embodiment, the temperature detector 3a is not limited to being provided on the upper surface of the probe card 3, but may be embedded in the probe card 3, for example. The data is not limited to the created one, and may be, for example, data previously stored in a floppy disk or the like. Further, the writing of the probe tip level of the probe needle 4 corresponding to the temperature of the probe card 3 into the memory 51 is performed by bringing the probe needle 4 into contact with the conductive plate as in the above-described embodiment and inputting an input signal to the data creation unit 5. The method is not limited to the method of writing the data into the memory 51 based on the probe needle 4 as shown in FIG.
Is irradiated with light from the light source 7, the reflected light is received by the light receiver 71, and the analysis unit 72 calculates the tip level of the probe needle 4 based on the output from the light receiver 71. May be written to the memory 51 via the data creation unit 5.

The control of the relative height position of the wafer W with respect to the probe card 3 is not limited to the control of driving the elevating mechanism 22 by the control signal from the control unit 6 to move the wafer holding table 2 up and down. The control may be such that the probe card 3 is moved up and down by a further control signal.

As described above, the surface level of the wafer W is controlled in consideration of overdrive, and the overdrive may be, for example, 30 μm to 70 μm.
In this case, the surface level of the wafer W may be controlled to be higher than that of the above-described embodiment by the amount of overdrive.

Further, the present invention can be applied to an LCD substrate as an object to be inspected.

[0032]

According to the present invention, the relative position of the test object is controlled based on the data of the height position of the probe tip after the heated test object is brought into contact with the probe needle. Therefore, the contact pressure of the probe tip of the probe needle to the surface of the test object can be measured with an appropriate strength independent of the temperature of the test object, and measurement can be performed. The probe needle can be prevented from being damaged.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for describing a main part of a probe device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional side view showing the entire configuration of the probe device according to the embodiment of the present invention.

FIG. 3 shows the relationship between the probe tip level of the probe needle and elapsed time,
FIG. 4 is a characteristic diagram showing a relationship between a surface level of an inspection object and an elapsed time.

FIG. 4 is an explanatory diagram for explaining another embodiment of the present invention.

FIG. 5 is an explanatory diagram for describing an example of detecting a needle tip level of a probe needle.

[Explanation of symbols]

 2 Wafer Holder 2a Current Monitor 22 Elevating Mechanism 22a Level Detector 3 Probe Card 4 Level Detector 5 Data Generator 6 Controller

Claims (1)

(57) [Claims] 1. A probe device for performing electrical measurement by bringing a plurality of probe needles arranged on a probe card into contact with an electrode pad of a device under test whose temperature has been adjusted to a high temperature. By contact with electrode pad
A probe device, comprising: a control unit that controls a relative position of a test object with respect to a probe card to make contact with the probe card based on data indicating a height position of a needle tip when heated .