JP3101755B2 - Method and apparatus for measuring semiconductor wafer - 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 semiconductor wafer, and more particularly to an improvement in measurement efficiency and measurement accuracy.

[0002]

2. Description of the Related Art Recently, a large number of chips are integrated on a single semiconductor wafer due to increase in size, integration, and density of the semiconductor wafer. From this,
In a semiconductor measuring device (probing machine), which is a machine that performs a final check of a wafer process, how efficiently and accurately the electrical characteristics of a large number of chips (semiconductor elements) arranged in a lattice on a semiconductor wafer are measured. The ability to measure is a major issue in improving productivity.

In the measurement of a semiconductor wafer with a wafer probing machine, generally, a Z stage supporting a semiconductor wafer is raised from a Z stage base position, and an electrode pad of a chip is moved to a tip of a probe needle provided on a probe card. The measurement is performed by sequentially energizing the tip of the needle while moving horizontally between the tips. At the time of this horizontal movement, the distance between the Z-stage base position and the tip of the probe needle is set to about 500 μm so that the semiconductor wafer surface does not come into contact with the probe needle and is damaged.

By the way, in order to perform the measurement accurately, after the probe tip of the probe needle is brought into contact with the electrode pad, the probe tip is overdriven (after the contact between the needle tip and the electrode pad surface, the electrical contact is made). In order to ensure that the needle tip bites into the electrode pad surface),
It is important to prevent dust on the electrode pad surface or shavings of the oxide film from adhering to the tip of the needle to cause poor contact. Conventionally, a double contact method has been mainly used as a measuring method for preventing the contact failure, and will be described with reference to FIGS. In FIG. 7, the vertical line indicates the vertical movement of the Z stage supporting the semiconductor wafer as the movement of the electrode pad 1 of the semiconductor wafer, and the horizontal line indicates that the probe needle 2 bends and the needle tip 3 becomes the electrode pad. This shows a state where one surface is displaced. FIG. 8 shows that the needle tip 3 is shifted from the surface of the electrode pad 1 so that the dust 4
And a state where the oxide film 4 is shaved. In this double contact method, first, the Z stage is raised by about 400 μm from the Z stage base position, and the electrode pad 1 surface is brought into contact with the probe tip 3 of the probe needle 2 (touch point position), and then the Z stage is further moved. The needle is raised by about 100 μm (overdrive position) to apply overdrive to the needle tip. As a result, the probe needle 2 bends and the needle tip 3 shifts from the point A in the figure to the point B in the figure while biting into the electrode pad 1 surface. Therefore, the electrode pad 1
The dust 4 and the oxide film 4 on the surface are scraped by the needle tip 3 and raked to the point B, so that the scraped portion 5 is in a good electrical conduction state. Next, the Z stage is returned from the overdrive position to the Z stage base position, raised again to the overdrive position, and brought into contact with the needle tip 3 and the electrode pad 1 for measurement.

[0005]

However, in the conventional double contact method, as is apparent from FIG. 7, each time measurement is performed, the Z stage moves between the base position of the Z stage and the overdrive position of about 500 μm. Since it moves up and down three times (approximately 1500 μm), there is a disadvantage that the measurement takes time and the measurement efficiency is poor. Also, as shown in FIG. 8, when the Z stage is raised for the second time, at the touch point position, the tip 3 has a portion where dust 4 or oxide film 4 is present and a portion where the tip 4 is removed. After hitting the point A which is the boundary position of, it shifts to the point B. For this reason, when the needle tip 3 hits a portion where the dust 4 or the oxide film 4 exists due to a slight deviation of the needle tip 3, the measurement is performed with the dust 4 or the oxide film 4 attached to the needle tip 3. Will be. As a result, there is a disadvantage that a contact failure easily occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a measuring method of a semiconductor wafer capable of improving the production efficiency since the measuring time can be shortened and the measuring accuracy can be improved. It is intended to provide a device.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for measuring a semiconductor wafer by measuring the electrical characteristics by contacting the tip of an inclined probe needle with the electrode pad surface of the semiconductor wafer. In the method, setting is made to move either the needle tip or the electrode pad surface,
First, the needle tip is moved to a touch point position to bring the needle tip into contact with the electrode pad surface, and then moved to an overdrive position to cause overdrive to act on the needle tip. After moving the crossed needle tip to the displacing position, return to the overdrive position and stop, while applying a current to the probe needle in the stopped state and measuring, the needle tip and the electrode pad surface Between contact and measurement
It is characterized in that the needle tip and the electrode pad surface are not separated.

[0008]

According to the present invention, the operation of accurately contacting the tip of the probe needle with the electrode pad surface of the semiconductor wafer in an electrically good contact state is performed in a short time. The invention will be described as a representative. According to the first aspect of the present invention, one of the probe needle and the semiconductor wafer is set to be moved. First, the probe needle and the semiconductor wafer are moved to the touch point position so that the probe tip of the probe needle and the electrode pad surface of the semiconductor wafer are moved. Make contact. Next, the needle is moved to the overdrive position to apply overdrive to the needle tip. As a result, the contact pressure at the needle tip increases and the probe needle bends,
The needle tip removes dust and oxide film on the electrode pad surface. Next, it is moved to a predetermined position beyond the overdrive position and then returned to the overdrive position and stopped. As a result, the bending degree of the probe needle changes, and the needle tip reciprocates on the electrode pad surface. By this reciprocating motion, dust and oxide film shaved by overdrive and the dust and oxide film shavings shaved by the reciprocating motion are scraped to both ends of the reciprocating motion, and the needle tip is formed on the electrode pad surface. Stops where the dust or oxide film has been removed. As a result, a good contact state is formed between the needle tip and the electrode pad surface. In this state, since the measurement is performed, no contact failure occurs.
In addition, the needle tip and the electrode pad surface are not separated from each other until the measurement after the contact between the needle tip and the electrode pad surface is performed.

As described above, according to the method for measuring a semiconductor wafer of the present invention, since the amount of movement of the probe tip or the semiconductor wafer that moves for measurement is significantly shorter than that of the conventional double contact method, the measurement time is reduced. It can be greatly reduced. In addition, the present invention provides a method in which, after overdrive is applied, the tip of the electrode pad is separated from the surface of the electrode pad once the dust or oxide film is not removed, as in the conventional double contact method in which the tip is once separated from the surface of the electrode pad. The danger of the needle tip coming into contact again can be reliably avoided, thereby improving the measurement accuracy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method and apparatus for measuring a semiconductor wafer according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a semiconductor wafer measuring apparatus 1 according to the present invention.
FIG. 2 is a schematic configuration diagram of a probing card 14 mounted on a card holder 12 supported by a head stage (not shown) of the measuring apparatus 10. Are connected to the probing card 14.
Is installed at a predetermined position with respect to. The probing card 14 is connected to a tester (not shown) so that a current can flow through the probe needle 16.

A positioning device 18 is arranged below the probing card 14, and the positioning device 18 is placed on an X-axis table 20 and a Y-axis table 22.
, And the Z stage 24 is further supported thereon. The Z stage 24 supports a rotatable chuck base 26, and a horizontally fixed chuck 28 is fixed to the tip of the chuck base 26. And chuck 2
8 is a semiconductor wafer 30 which is an object to be measured which is fixed by suction
Are chips (semiconductor elements) formed in a grid on the semiconductor wafer 30 by the X-axis table 20 and the Y-axis table 22
Are performed, and the Z stage 24 moves up and down. As a result, the probe needle 16 of the probing card 14 is accurately positioned on the electrode pad surface of the chip so as to make correct contact, and when the measurement of one chip is completed, the accurate horizontal position for measuring the next chip is obtained. Movement is performed. And the semiconductor wafer 3
In a state where the electrode pad of No. 0 and the probe needle 16 of the probing card 14 are in contact with each other, a current is applied to the probe needle 16 to check whether the electrical characteristics of the chip are appropriate.

The control of the direction of movement and the amount of movement of the positioning device 18 is controlled by a control device 32, into which a program for performing the semiconductor wafer measuring method of the present invention is input. Next, using FIGS. 2 and 3, the semiconductor wafer measuring apparatus 1 configured as described above will be described.
The method for measuring a semiconductor wafer according to the present invention, which is performed according to the present invention, will be described. 2, the vertical line indicates the vertical movement of the Z stage 24 that supports the semiconductor wafer 30 via the chuck 28 as the movement of the surface of the electrode pad 34 of the semiconductor wafer 30, and the horizontal line indicates that the probe needle 16 This shows a state in which the needle tip 36 is displaced from the surface of the electrode pad 34 by bending. FIG. 3 shows that the needle tip 36 is shifted from the surface of the electrode pad 34 so that the dust 38 and the oxide film 3 on the surface of the electrode pad 34 are displaced.
8 shows a state of cutting. Also, in these figures, the order of the vertical movement of the Z stage 24 is shown.

First, the semiconductor wafer 30 is placed on the chuck 28.
Is mounted and fixed to the chuck 28 by vacuum suction.
At this time, the electrode pad 34 is at the base position of the Z stage 24. Next, the Z stage 24 is raised by 400 μm from the Z stage base position to bring the surface of the electrode pad 34 into contact with the needle tip 36 of the probe needle 16 (touch point position), and then the Z stage 24 is further raised by about 100 μm (over (Drive position), the needle tip 36 is overdriven, and the needle tip 36 shifts from point A to point B in the electrogram while biting into the electrode pad 34 surface. At this time,
Since the probe needle 16 is fixed, the probe needle 16
As a result, the needle tip 36 shifts on the surface of the electrode pad 34. As a result, the dust 38 adhered to the surface of the electrode pad 34 and the oxide film 38 formed on the surface of the electrode pad 34
Among them, the dust 38 and the oxide film 38 at the point B are scraped from the point A where the needle tip 36 is displaced, and are scraped to the point B.

The process up to this point is the same as the conventional double contact system. Next, in the method for measuring a semiconductor wafer of the present invention, the Z stage 24 is further raised by 50 μm from the overdrive position, and the needle tip 36 on the surface of the electrode pad 34 is moved.
Is shifted from the point B to the point C, and then the Z stage 24 is moved to 50 points.
The needle tip 36 is moved down from the point C to the point B while moving the needle tip 36 on the surface of the electrode pad 34 by lowering by μm. In the reciprocating movement of the needle tip 36, the needle tip 36 shifts from the point B to the point C, so that the dust 38 and the oxide film 38 raked up to the point B by overdrive and the new from the point B to the point C are newly formed. The shaved dust 38 and the oxide film 38 are raked up to the point C and deposited at the point C. Then, when the needle tip 36 returns from the point C to the point B, the dust 38 is left attached to the needle tip 36 or remains when the needle tip 36 shifts from the point B to the point C.
The oxide film 38 is scraped to the point B and deposited on the point A side of the point B. That is, after the overdrive is applied to the needle tip 36, the electrode pad 34 is reciprocated while the needle tip 36 is kept in contact with the surface of the electrode pad 34, so that the dust 38 and the oxide film 38 on the surface of the electrode pad 34 are removed. The needle tip 36 is brought into contact with the shaved portion 40 which is scraped to both ends of the reciprocating motion and is in an electrically good conduction state. Since measurement is performed in this state, no contact failure occurs.

When measuring the next chip,
After returning the Z stage 24 to the base position of the Z stage, the Z stage 24 is horizontally moved to the next chip, and the Z stage 24 is moved up and down in the order described above. Thus, in the method of measuring a semiconductor wafer according to the present invention, the operating distance of the Z stage 24 is significantly reduced as compared with the conventional double contact method, so that the measurement time can be reduced. That is, the operating distance of the Z stage 24 per measurement is 60 in the semiconductor wafer measurement method of the present invention in the above-described embodiment.
In contrast to 0 μm, it is 1500 μm in the measurement method using the conventional double contact method.
Can measure 5 times faster. Therefore, the measurement efficiency can be dramatically improved.

In the case of the measuring method of the present invention, the needle tip 36
Since the tip 36 and the electrode pad 34 are kept in contact with each other until the measurement is completed after the contact between the tip 36 and the surface of the electrode pad 34, the tip 36 is once separated from the surface of the electrode pad 34 and brought into contact again. As in the double contact method described above, the danger that the needle tip 36 comes into contact with the portion (point A) of the surface of the electrode pad 34 where the dust 38 and the oxide film 38 have not been removed can be reliably avoided. . As a result, the probability of occurrence of a contact failure is drastically reduced, so that the measurement accuracy can be improved.

Next, another embodiment of the method for measuring a semiconductor wafer according to the present invention will be described with reference to FIG. In the first embodiment,
After the overdrive was applied, the Z stage 24 was moved up and down by the same distance (50 μm) to return to the needle tip 36 overdrive position (point B). However, as shown in FIG. If not below the position,
The descending distance may be smaller than the ascending distance (point E) or larger (point D). Thereby, when measuring, the needle tip 3
The contact pressure at which the electrode 6 contacts the electrode pad 34 can be set to an optimum condition.

Next, still another embodiment of the semiconductor wafer measuring method of the present invention will be described with reference to FIG. First and second
In the embodiment, after the overdrive is applied to the needle tip 36, the Z stage 24 is first raised and then lowered.
However, the present invention is not limited to this, and as shown in FIG. 5, first, it may be lowered to about an intermediate position between the overdrive position and the touch point position and then raised. In this case as well, it is not necessary to make the Z stage 24 descend and ascend at the same distance. As shown in FIG. 6, if the Z stage 24 does not fall below the touch point position, even if the ascending distance is smaller than the descending distance (point D). The contact pressure at the needle tip can be set to an optimum condition.

In this embodiment, the semiconductor wafer 30 is
The probe 24 is moved up and down by the stage 24 to come into contact with the probe tip 36 of the probe needle 16, but the probing card 14 supporting the probe needle 16 may be moved up and down. In addition, although an example has been described in which the needle tip reciprocates only once on the electrode pad surface after overdrive, it may reciprocate a plurality of times. Further, the amount of overdrive used in the present embodiment and the amount of vertical movement after overdrive are not limited to these.

[0020]

As described above, according to the method and the apparatus for measuring a semiconductor wafer of the present invention, one of the inclined probe needle and the semiconductor wafer is set to be moved, and the needle tip is first set. After moving the needle tip so that it comes into contact with the electrode pad surface, and then moving it up and down while shifting it so that the overdrive acts on the needle tip, the needle tip is kept in contact with the electrode pad surface, and then the needle tip is moved to the electrode pad surface. The measurement was performed after moving so as to reciprocate on the surface.

Thus, the operation of accurately contacting the tip of the probe needle with the electrode pad surface of the semiconductor wafer in an electrically good contact state can be performed in a short time. Therefore, according to the present invention, as compared with the conventional double contact method, the measurement time can be significantly reduced, the measurement accuracy can be improved, and the productivity can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a semiconductor wafer measuring apparatus according to the present invention.

FIG. 2 is an explanatory diagram illustrating a method for measuring a semiconductor wafer according to the present invention, showing vertical movement of a Z stage.

FIG. 3 is an explanatory view of a method for measuring a semiconductor wafer according to the present invention, and shows a state in which dust or an oxide film on an electrode pad surface is shaved by a stylus tip displacing the electrode pad surface.

FIG. 4 is an explanatory view illustrating another embodiment of the semiconductor wafer measurement method of the present invention.

FIG. 5 is an explanatory view illustrating still another embodiment of the method for measuring a semiconductor wafer according to the present invention.

FIG. 6 is an explanatory view illustrating still another embodiment of the method for measuring a semiconductor wafer according to the present invention.

FIG. 7 is an explanatory view for explaining a conventional method for measuring a semiconductor wafer, showing the vertical movement of a Z stage.

FIG. 8 is an explanatory view for explaining a conventional method of measuring a semiconductor wafer, and shows a state in which dust and an oxide film on an electrode pad surface are shaved by a tip of the needle being displaced from the electrode pad surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Semiconductor wafer measuring device 14 ... Probe card 16 ... Probe needle 18 ... Positioning device 20 ... X axis table 22 ... Y axis table 24 ... Z stage 28 ... Chuck 30 ... Semiconductor wafer 32 ... Control device 34 ... Electrode pad 36 ... Needle point 38 ... Dust or oxide film on electrode pad surface 40 ... Shaved portion on electrode pad surface

────────────────────────────────────────────────── ─── Continued on the front page (72) Eiji Kurokawa, Inventor 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (56) References JP-A-6-124985 (JP, A) JP-A-5 -326655 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/66

Claims (8)

(57) [Claims] [Claim 1] In the measuring method of a semiconductor wafer measuring the needle tip and contacting the electrode pad surface of the semiconductor wafer electrical properties of the tilted probe needles, either the tip or the electrode pad surface One of them is set to be moved. First, the needle tip is moved to a touch point position to bring the needle tip into contact with the electrode pad surface . Then, the needle tip is moved to an overdrive position to apply an overdrive to the needle tip. Then, after moving the needle tip beyond the overdrive position to the shift position, return to the overdrive position and stop, and in the stopped state, apply a current to the probe needle. The semiconductor wafer is characterized in that the needle tip and the electrode pad surface are not separated from each other after the measurement and the contact between the needle tip and the electrode pad surface until the measurement. C measuring method. 2. The needle beyond the overdrive position.
2. The method for measuring a semiconductor wafer according to claim 1, wherein the semiconductor wafer is moved to a position where the tip is shifted, then returned to a position short of an overdrive position and stopped. 3. The needle beyond the overdrive position.
2. The method for measuring a semiconductor wafer according to claim 1, wherein the tip is moved to a position where the tip is shifted, and then returned and stopped between the overdrive position and the touch point position. 4. A semiconductor wafer measuring method for measuring electrical characteristics by bringing a needle tip of an inclined probe needle into contact with an electrode pad surface of a semiconductor wafer, wherein the needle tip or the electrode pad surface is provided. One of them is set to be moved. First, the needle tip is moved to a touch point position to bring the needle tip into contact with the electrode pad surface . Then, the needle tip is moved to an overdrive position to apply an overdrive to the needle tip. Next, the needle tip is moved to a position where the needle tip is shifted between the overdrive position and the touch point position, and then returned to the overdrive position to stop. In the stopped state, current is supplied to the probe needle. Between the needle tip and the electrode pad surface, and do not separate the needle tip and the electrode pad surface from the time when the needle tip is brought into contact with the electrode pad surface until the measurement. Measurement method for a semiconductor wafer characterized by and. 5. The semiconductor according to claim 4, wherein the needle is moved between the overdrive position and the touch point position, and then moved to a position where the needle tip exceeding the overdrive position is shifted and stopped. Wafer measurement method. 6. The semiconductor according to claim 4, wherein the needle tip is moved to a position where the needle tip is shifted between the overdrive position and the touch point position, and then returned to a position short of the overdrive position and stopped. Wafer measurement method. 7. A semiconductor wafer measuring device for measuring an electrical characteristic by bringing a tip of a tilted probe needle into contact with an electrode pad surface of a semiconductor wafer, wherein: a supporting device for supporting the probe needle; A mounting device that is provided below the supporting device and that mounts the semiconductor wafer; and a moving unit that moves one of the supporting device and the mounting device in the vertical direction; and either one, is moved to the touch Tsu point position is brought into contact with the needle tip and the electrode pad surface, then, by the action of overdrive the probe tip is moved to the overdrive position, then over and control means for controlling the moving means to stop back to the overdrive position after moving the needle tip beyond the drive position to the deviated position <br/> location A measuring device for measuring the current by passing a current through the probe needle, and the probe tip and the electrode pad surface are not separated from each other until the measurement is performed after the probe tip is brought into contact with the electrode pad surface. An apparatus for measuring a semiconductor wafer, comprising: 8. A semiconductor wafer measuring device for measuring electrical characteristics by bringing a needle tip of an inclined probe needle into contact with an electrode pad surface of a semiconductor wafer, wherein: a supporting device for supporting the probe needle; A mounting device provided below the supporting device, for mounting the semiconductor wafer, moving means for vertically moving one of the supporting device and the mounting device, and either, and the probe tip is moved to the touch Tsu point position the electrode pad
Surface, and then moved to an overdrive position to apply overdrive to the needle tip,
Forward between the overdrive position and the touch point position
Control means for controlling the moving means so as to return to the overdrive position and then stop after moving the needle point to the shifted position , and a measuring device for applying a current to the probe needle and measuring the current, An apparatus for measuring a semiconductor wafer, wherein the probe tip and the electrode pad surface are not separated from each other until the probe tip is brought into contact with the electrode pad surface before measurement.