JP3094056B2 - 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 for measuring electrical characteristics of a device under test such as a semiconductor device.

[0002]

2. Description of the Related Art As is well known, a large number of semiconductor devices are formed on a single semiconductor wafer by using a precision photo transfer technique or the like, and thereafter, the wafer is cut for each semiconductor device. In the manufacturing process of such a semiconductor device, a test determination of electrical characteristics of a semi-finished semiconductor device is conventionally performed using a probe device in a semiconductor wafer state, and as a result of the test measurement, it is determined that the semiconductor device is non-defective. Only those that have been sent are sent to a post-process such as packaging to improve productivity.

[0003] The probe device includes a mounting table as a test object mounting table configured to be movable in XYZ-θ directions, and a semiconductor device as a test object is mounted on the mounting table. A probe card having a large number of probe needles corresponding to the electrode pads on the wafer is fixed. Then, the semiconductor wafer is set on the mounting table, the mounting table is driven to bring a probe needle into contact with the electrode pad of the semiconductor wafer, and test measurement is performed by a tester via the probe needle.

FIGS. 9 and 10 show a schematic structure of a probe device, in which a main stage 2 is provided substantially at the center of a main body 1. FIG. The main stage 2 is provided with a mounting table 3 for a semiconductor wafer W as an object to be inspected. The main stage 2 is movable together with the mounting table 3 in the X and Y directions in a horizontal plane.
A probe mechanism 4 is provided above the mounting table 3.

A multi-stage cassette holder 5 is provided on one side of the main body 1, and a wafer cassette 6 which accommodates a plurality of semiconductor wafers W at predetermined intervals in a vertical direction is detachable from the cassette holder 5. It is supported by. The wafer cassette 6 has a substantially rectangular box shape, and has an opening 6a on one side for taking in and out the semiconductor wafer W. The wafer cassette 6 is placed in a state where the opening 6a faces the rear of the main body 1 and the cassette holder. 5 supported.

Further, the semiconductor wafer W in the wafer cassette 6 is taken out of the main body 1 located on the side of the opening 6a of the wafer cassette 6, transferred to the mounting table 3 of the main stage 2, and the semiconductor for which measurement has been completed. A load / unload mechanism 7 having tweezers for returning the wafer W into the wafer cassette 6, a pre-alignment mechanism 8 for positioning the semiconductor wafer W, and a wafer size detector 9 are provided.

When the semiconductor wafer W in the wafer cassette 6 is transferred to the mounting table 3 of the main stage 2 to measure the electrical characteristics of each semiconductor device on the semiconductor wafer W, the load / unload mechanism 8 is used. The semiconductor wafer W is taken out from the wafer cassette 6 by a pre-alignment mechanism 8, pre-aligned by the pre-alignment mechanism 8, and then the size of the semiconductor wafer W (for example, 4 inches, 5 inches, 6 inches and 8 inches). After detecting the wafer size, the load / unload mechanism 8 places the semiconductor wafer W on the mounting table 3.
Has been brought in.

[0008]

However, in the conventional probe device, it is required that a single probe device can perform a common inspection on 6-inch and 8-inch wafers. Before inspection, it is necessary to recognize the wafer size.
The wafer size detector 9 is installed at a position symmetrical to the wafer cassette 6 with respect to the rotation center of the load / unload mechanism 8 or one side from a line connecting the rotation center of the load / unload mechanism 8 and the wafer cassette 6. It is installed at a position deviated from.

That is, it is conceivable that the wafer size detecting section 9 is provided at a site different from the path for taking out the semiconductor wafer W from the wafer cassette 6 by the tweezers of the load / unload mechanism 8 and transporting the semiconductor wafer W to the mounting table 3.
In this case, when detecting the size of the semiconductor wafer W gripped and taken out of the wafer cassette 6 by the tweezers, it is necessary to turn the tweezers to position the semiconductor wafer W on the wafer size detection unit 9. In other words, the semiconductor wafer W can be moved in and out of the wafer cassette 6 by one-axis drive in which the tweezers are moved straight forward and backward. However, the tweezers are turned to position the semiconductor wafer W on the wafer size detector 9. Requires a two-axis drive, which complicates the structure and increases the semiconductor wafer W
There is a problem that the cycle time for entering and exiting the vehicle increases.

[0010] Semiconductor manufacturing-related equipment is expensive due to the demand for advanced technology and high development costs, but the technology development of semiconductor elements grows at a rapid pace, and in terms of business feasibility, manufacturing equipment-related equipment is required. There is a strong demand for lower prices. Inspection of objects of different sizes with one probe device is consistently inexpensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to remove an object to be inspected from a cassette and to reduce the size of the object to be inspected during the transportation to a mounting table of a main stage. It is an object of the present invention to provide a probe device capable of detecting, and simplifying the structure and shortening the cycle time.

[0012]

[0013]

[0014]

The present invention achieves the above object.
In order to achieve this, a plurality of test objects stored in the cassette are gripped by a retractable load tweezers and carried out of the cassette, and the test objects are pre-aligned by an alignment mechanism. A probe device having a load / unload mechanism for transporting the test object to the measurement unit and holding the test object, which has been inspected by the measurement unit, with unloading tweezers and carrying the test object into the cassette; In the vicinity of the load tweezers, a size detection unit including a light emitting element and a light receiving element for detecting the size of the inspection object gripped by the load tweezers is provided on an advancing / retreating path of the load tweezers. Characterized in that a notch portion for passing the irradiation light is provided.

According to a second aspect of the present invention, a plurality of semiconductor wafers housed in a wafer cassette are gripped by load-and-retractable load tweezers and unloaded from the wafer cassette, and the semiconductor wafer is pre-aligned by an alignment mechanism. And a loading / unloading mechanism for transporting the semiconductor wafer, which has been inspected by the measuring unit, to the measuring unit, and holding the semiconductor wafer by unloading tweezers and loading the semiconductor wafer into the wafer cassette. A wafer center detecting means for calculating the diameter of the semiconductor wafer and extracting the center of the semiconductor wafer by using the wafer center detection sensor and the load tweezers for taking out the semiconductor wafer from the wafer cassette; And the alignment mechanism In the vicinity, characterized in that a size detecting unit for detecting the size of the inspection object on the advance and retreat path of the load tweezers.

[0016]

When the test object stored in the cassette is gripped by the load tweezers by moving the load tweezers forward, the load tweezers are retracted and taken out, and then the test object is positioned on the alignment mechanism for pre-alignment. The size of the object to be inspected taken out is detected by the size detection section, and the stroke of the load tweezers can be controlled by this detection signal.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a first embodiment, in which the same components as in the prior art are assigned the same reference numerals and explanations thereof are omitted. 1 and 2 show a load / unload mechanism 11 of the probe device.
Numeral 12 denotes an inspection object container, for example, a wafer cassette. The wafer cassette 12 has a substantially rectangular box shape, and is provided on one side with an opening 12a for inserting and removing an object to be inspected, for example, a semiconductor wafer W. Inside the wafer cassette 12, a plurality of semiconductor wafers W as inspection objects are stored at equal intervals in the vertical direction.

A wafer ejection detection sensor 10 is provided near the opening 12a of the wafer cassette 12. The wafer ejection detection sensor 10 includes a wafer cassette 12
Light emitting element 10 installed on the lower edge side of opening 12a
a, and a light receiving element 10b provided on the upper edge side. When the semiconductor wafer W inside the wafer cassette 12 jumps out of the opening 12a, the irradiation light from the light emitting element 10a is blocked at the peripheral edge of the semiconductor wafer W. It is possible to detect by being performed.

The means for loading and unloading wafers into and from the cassette 12, that is, the loading / unloading mechanism 11, is as follows, for example. That is, the base 13 is provided with the main body 15 that is rotatable around the rotation main shaft 14. For example, two load tweezers 16 and unload tweezers 17 that can move forward and backward in a front-rear direction by a guide rail (not shown) are vertically arranged above the main body 15 and are horizontally disposed.

The means for driving the semiconductor wafer W forward and backward with respect to the wafer cassette 12 by the load tweezers 16 and the unload tweezers 17 is constituted, for example, as follows. That is, a loading motor 19a and an unloading motor 19b, which can be rotated forward and backward, respectively, are fixed to the rear portions on both sides of the main body portion 15 by the bracket 18 with their rotating shafts 20 directed vertically. A pulley 21 is provided on the rotation shaft 20, and a pulley 23 is rotatably supported by a support shaft 22 at a front portion of the main body 15 corresponding to the pulley 21. Pulleys 21 and 2
3 are located at the same height.
An endless belt 24 is stretched between them.

Accordingly, endless belts 24 are arranged in parallel on both sides of the main body 15, and the middle of one endless belt 24 is connected to the base end of the load tweezers 16 via a connecting member 25. The middle part of the other endless belt 24 is connected to the base end of the unloading tweezers 17 via a connecting member 25. That is, the running of the endless belt 24 causes the load tweezers 16 and the unload tweezers 17 to independently advance and retreat in the front-rear direction.

The load tweezers 16 and the unload tweezers 17 have basically the same shape and are configured as shown in FIG. That is, the load tweezers 16 and the unload tweezers 17 are formed of a rectangular plate-like body made of a synthetic resin material or the like. In order to support the semiconductor wafer W, a pair of support pieces 16a,
16b are provided, and these support pieces 16
A notch 26 for use as an optical path for photoelectrically detecting the wafer size is provided at the base end between the holes a and 16a. Further, the support pieces 16a, 16a are provided with a vacuum suction hole 27 opened on the upper surface for temporarily fixing the wafer when the wafer is supported, and communicate with a vacuum suction source (not shown).

On the front side of the main body 15, an alignment mechanism 28 is provided at a portion facing between the support pieces 16a, 16a when the load tweezers 16 and the unload tweezers 17 are retracted. . As shown in FIGS. 4 and 5, the alignment mechanism 28 is provided with a guide post 30 with respect to a base 29 provided on the main body 15.
Are vertically erected, and the upper end of the guide post 30 is supported by a fixed arm 31 fixed to the upper part of the main body 15.

The guide post 30 is provided with a vertically movable fitting body 32, and a plate 33 is fixed to the fitting body 32. Therefore, the plate 33 moves up and down while maintaining the horizontal state, and is urged downward by the tension spring 34.

Further, the guide post 3 is
The first cylinder 35 and the second cylinder 36 are fixed with the rods 35a and 36a oriented vertically in a state where 0 is interposed therebetween. The rod 35a of the first cylinder 35 has a large stroke, and the rod 36a of the second cylinder 36 has a small stroke.
Can be lifted up from below.

An alignment motor 37 is fixed to the plate 33 with the rotating shaft 38 oriented vertically.
An alignment stage 39 having a chuck function capable of vacuum-sucking the semiconductor wafer W is provided on the upper end of the rotating shaft 38.
Is provided. The alignment stage 39 has a disk shape, and the distance between the center 39a of the alignment stage 39 and the wafer ejection detection sensor 10 is set to a fixed numerical value P.

Further, a wafer size detecting section 40 is provided on the path for the load tweezers 16 to advance and retreat, for example, at or near the alignment mechanism 28. The wafer size detection unit 40 includes, for example, a light emitting element 41 fixed to the upper surface of the main body 15 and a light receiving element 4 fixed to the fixed arm 31.
2 are installed facing each other, and the irradiation light from the light emitting element 41 passes through the cutouts 26 of the load tweezers 16 and the unload tweezers 17 and is incident on the light receiving element 42.

Here, the irradiation light from the light emitting element 41 is located at the outer peripheral edge of the semiconductor wafer W attracted to the alignment stage 39, and the light receiving element 42 is the size of the semiconductor wafer W ( For example, a plurality of light receiving units for 4 inches, 5 inches, 6 inches, and 8 inches are separately arranged so as to detect 4 inches, 5 inches, 6 inches, and 8 inches, respectively.

That is, when only the 4-inch light-receiving portion of the light-receiving element 42 is shielded from light by the semiconductor wafer W, it is determined that the wafer size is 4 inches, and the 4- and 5-inch light-receiving portions are shielded from light by the semiconductor wafer W. Then, it is determined that the wafer size is 5 inches. Similarly, when the light receiving portions for 4, 5 and 6 inches are shielded from light by the semiconductor wafer W, it is determined that the wafer size is 6 inches, and the light receiving portions for 4, 5, 6, and 8 inches are detected by the semiconductor wafer W. When the light is shielded, it can be determined that the wafer size is 8 inches.

Next, the operation of the probe device configured as described above will be described. When the semiconductor wafer W inside the wafer cassette 12 is taken out by the load / unload mechanism 11 and carried into the measuring section, first, the load motor 19a rotates forward and the endless belt 24 runs forward. Accordingly, the load tweezers 16 connected to the endless belt 24 via the connecting member 25 moves forward.

When the load tweezers 16 moves forward to the forefront end, the support pieces 16a, 16a at the tips thereof are opened.
The semiconductor wafer W is inserted into the wafer cassette 12 from 2a and faces the lower side of the semiconductor wafer W to be taken out. Here, when the cassette holder 5 is lowered by one pitch, the semiconductor wafer W is placed on the support pieces 16a, 16a of the load tweezers 16, and at the same time, the semiconductor wafer W is moved by the vacuum suction force from the vacuum suction holes 27 to the support piece 16a. , 16a.

Next, when the load motor 19a rotates in the reverse direction, the endless belt 24 runs backward. Therefore, the load tweezers 16 connected to the endless belt 24 via the connecting member 25 retreat, and the semiconductor wafer W is pulled out from the wafer cassette 12.

That is, as shown in FIG. 6, the light-emitting element 10 of the wafer jump detection sensor 10
The light receiving element 10b detects the start of the passage of the semiconductor wafer W (a) in order to shield the irradiation light from the light a. When the load tweezers 16 further retreats, the semiconductor wafer W is taken out of the wafer cassette 12, and the irradiation light from the light emitting element 10a enters the light receiving element 10b, the end of the passage of the semiconductor wafer W (b) is detected.

As described above, when the semiconductor wafer W is taken out and the front and rear ends of the peripheral edge thereof are detected by the wafer ejection detection sensor 10, the diameter L of the semiconductor wafer W is measured based on the passage time of the semiconductor wafer W. can do. Further, the center (C) of the semiconductor wafer W can be extracted by calculating Ｌ L of the diameter by the arithmetic circuit, and from the center (C) to the center 39 a of the alignment stage 39 of the alignment mechanism 28.
In other words, by retracting the load tweezers 16 at (P-1 / 2L) until the load tweezers 16 stop, the center (C) of the semiconductor wafer W taken out is centered on the alignment stage 39.
9a.

Here, when the vacuum suction from the vacuum suction hole 27 is stopped, the semiconductor wafer W supported by the load tweezers 16 is in a free state, and the alignment mechanism 28
Operates. That is, when the first cylinder 35 operates, the rod 35a projects and pushes up the plate 33,
Since the alignment stage 39 moves up together with the motor 37 fixed to the plate 33, the semiconductor wafer W supported by the load tweezers 16 is transferred to the alignment stage 39.

When the motor 37 rotates in this state, the alignment stage 39 rotates while supporting the semiconductor wafer W, and pre-alignment of the semiconductor wafer W is performed. At this time, the irradiation light emitted from the light emitting element 41 of the wafer size detecting unit 40 provided adjacent to the alignment mechanism 28 passes through the cutouts 26 of the load tweezers 16 and the unload tweezers 17 and enters the light receiving element 42. Therefore, when light is blocked at the peripheral edge of the semiconductor wafer W, the size of the wafer can be determined by the light-shielded light receiving unit. That is, when only the light receiving section for 4 inches is shielded from light by the semiconductor wafer W, it is determined that the wafer size is 4 inches. When the light receiving section for 4 and 5 inches is shielded from light by the semiconductor wafer W, the wafer size is 5 inches. It can be determined to be inches.

Accordingly, in the process of taking out the semiconductor wafer W to be measured from the wafer cassette 12 by the load tweezers 16, prealignment of the semiconductor wafer W and determination of the wafer size can be performed. Load tweezers 1 when W is carried into mounting table 3 of main stage 2
6 can be controlled.

When the pre-alignment of the semiconductor wafer W and the discrimination of the wafer size are completed, the first cylinder 35 operates to lower the rod 35a, and the alignment stage 3
The semiconductor wafer W placed on 9 is transferred again to the support pieces 16a, 16a of the load tweezers 16 and is sucked by the vacuum suction force of the vacuum suction holes 27.

Next, when the main body 15 of the loading / unloading mechanism 11 is rotated by 90 ° about the rotating spindle 14 as an axis,
The tip of the main body 15 faces the mounting table 3 of the main stage 2. Then, the load motor 19a rotates forward again and the endless belt 24 runs forward. Therefore,
The load tweezers 16 connected to the endless belt 24 via the connecting member 25 advance, and after the semiconductor wafer W is placed on the mounting table 4, the load tweezers 16 retreat. Then, measurement of each semiconductor device of the semiconductor wafer W is performed. The wafer size signal is further controlled to be transmitted to a measurement area drive system for measurement, an inker or a memory of measurement results, and an optical system.

When the measurement of the semiconductor device is completed, the unloading motor 19b rotates forward and the endless belt 24 rotates.
Runs forward. Therefore, the endless belt 24
The unloading tweezers 17 connected via the connecting member 25 to the front moves forward, and sucks the semiconductor wafer W on the mounting table 3 for which measurement has been completed.

The support piece 17 of the unloading tweezers 17
When the semiconductor wafer W is sucked by the vacuum suction holes 27 provided in the a and 17a, the unloading motor 19b rotates in the reverse direction, and the unloading tweezers 17 retreats. Main body 15
Is rotated by 90 ° in the direction opposite to the above with the rotation main shaft 14 as the axis, and the front end of the main body 15 faces the wafer cassette 12.

Here, when the vacuum suction from the vacuum suction holes 27 is stopped, the semiconductor wafer W supported by the unloading tweezers 17 is in a free state, and the alignment mechanism 28 operates. That is, when the second cylinder 36 is operated, the rod 36a protrudes to push up the plate 33, and the alignment stage 39 moves up together with the motor 37 fixed to the plate 33, so that the semiconductor wafer W supported by the unloading tweezers 17 is moved. Is transferred to the alignment stage 39.

In this state, when the motor 37 rotates, the alignment stage 39 rotates while supporting the semiconductor wafer W, and pre-alignment of the measured semiconductor wafer W is performed. When the pre-alignment is completed, the second
The cylinder 36 operates to lower the rod 36a, and the semiconductor wafer W placed on the alignment stage 39 is
Again, the support pieces 17a, 17 of the unloading tweezers 17
a and is sucked by the vacuum suction force of the vacuum suction hole 27.

Then, the unloading motor 19b rotates forward again and the endless belt 24 runs forward. Accordingly, the unloading tweezers 17 connected to the endless belt 24 via the connecting member 25 moves forward, returns the semiconductor wafer W to the wafer cassette 12, and then the unloading tweezers 17 retreats to complete one cycle.

As described above, in the process of taking out the semiconductor wafer W to be measured from the wafer cassette 12 by the load tweezers 16, the pre-alignment of the semiconductor wafer W and the discrimination of the wafer size can be performed, and the wafer size can be confirmed as in the prior art. There is no need to rotate the tweezers to perform the operation, and only one shaft for linearly moving the tweezers forward and backward can be used, and the structure can be simplified.

FIGS. 7 and 8 show a second example of the alignment mechanism.
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. In this alignment mechanism 50, a first cylinder 51 set to a stroke of 25 mm and a second cylinder 52 set to a stroke of 15 mm are fixed with their rods 51a, 51a directed vertically. Further, a two-stage stroke cylinder 53 is fixed to the plate 33 with its rod 54 oriented vertically, and an alignment stage 55 having a chuck function capable of vacuum-sucking the semiconductor wafer W is provided at the upper end of the rod 54. Is provided.

Therefore, when the alignment of the semiconductor wafer W before measurement is performed, first, the first cylinder 51 is operated, and the rod 51a projects 25 mm at a high speed to push up the plate 33. Next, the 2 fixed to the plate 33
When the stepped stroke cylinder 53 operates and the rod 54 moves up to the height of H + α at a low speed, the alignment stage 55 rises, so that the semiconductor wafer W supported by the load tweezers 16 is transferred to the alignment stage 55.

When the pre-alignment is completed, the two-stage stroke cylinder 53 operates to lower the rod 54 to the height H, and the semiconductor wafer W on the alignment stage 55 is transferred to the load tweezers 16.

When the alignment of the semiconductor wafer W after the measurement is performed, first, the second cylinder 52 is operated, and the rod 52a protrudes by 15 mm at a high speed to push up the plate 33. Next, the two-stage stroke cylinder 53 fixed to the plate 33 operates, and the rod 54
When the alignment stage 55 rises to the height of α, the semiconductor wafer W supported by the unloading tweezers 17 is transferred to the alignment stage 55.

When the pre-alignment is completed, the two-stage stroke cylinder 53 operates to lower the rod 54 to the height H, and the semiconductor wafer W on the alignment stage 55 is transferred to the unloading tweezers 17.

Thus, the first and second cylinders 5
The plate 33 is raised at a high speed to a certain height by 1 and 52, and then the rod 54 is raised at a low speed by operating the two-stage stroke cylinder 53, so that the impact force of the alignment stage 55 on the semiconductor wafer W is reduced. Damage to the semiconductor wafer W can be prevented.

[0052]

As described above, according to the present invention, the size for detecting the size of the device under test is located near the alignment mechanism of the device under test and on the path of the load tweezers for transporting the device under test. By providing the detection unit, the size of the object to be inspected can be detected while the object to be inspected is taken out of the cassette and transported to a target portion.

Therefore, it is not necessary to rotate the tweezers to position the object to be inspected at the size detecting portion of another part as in the prior art, and only one axis for moving the tweezers straight forward and backward is required, and the structure is simplified. Can be planned,
In addition, there is an effect that workability can be improved by shortening the cycle time.

[Brief description of the drawings]

FIG. 1 is a side view of a load / unload mechanism of a probe device according to a first embodiment of the present invention.

FIG. 2 is a side view as seen from the direction of arrow A in FIG. 1;

FIG. 3 is a plan view of the alignment mechanism of the embodiment.

FIG. 4 is a side view of the alignment mechanism of the embodiment.

FIG. 5 is a side view as seen from the direction of arrow B in FIG. 4;

FIG. 6 is an operation explanatory view of the embodiment.

FIG. 7 is a side view of an alignment mechanism showing a second embodiment of the present invention.

FIG. 8 is a side view of the alignment mechanism showing the embodiment.

FIG. 9 is a schematic front view of a conventional probe device.

FIG. 10 is a schematic plan view of the probe device.

[Explanation of symbols]

 11 Load / Unload Mechanism 12 Wafer Cassette 16 Load Tweezers 17 Unload Tweezers 28 Alignment Mechanism 40 Wafer Size Detector

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/66 H01L 21/68

Claims (2)

(57) [Claims] 1. A plurality of test objects stored in a cassette are grasped by load tweezers which can be moved forward and backward, carried out of the cassette, pre-aligned by a test object by an alignment mechanism, and then measured. A probe device having a load / unload mechanism for holding the object to be inspected by the measurement unit with unloading tweezers and carrying the object into the cassette while transporting the object to be inspected by the measurement unit. A size detector comprising a light-emitting element and a light-receiving element for detecting the size of the object to be inspected is provided on the path of the load tweezers, and a cutout for passing irradiation light from the light-emitting element is provided in the load and unload tweezers. A probe device characterized by the above-mentioned. 2. A semiconductor device comprising: a plurality of semiconductor wafers stored in a wafer cassette which are gripped by load-and-retractable load tweezers and unloaded from the wafer cassette; the semiconductor wafer is pre-aligned by an alignment mechanism; And a semiconductor wafer that has been inspected by the measuring unit is gripped by unloading tweezers and loaded into the wafer cassette.
In a probe device having an unloading mechanism, a wafer ejection detection sensor is provided at an opening of the wafer cassette, and a diameter of the semiconductor wafer is calculated by using the wafer ejection detection sensor and load tweezers for extracting a semiconductor wafer from the wafer cassette. A wafer center extracting means for extracting the center of the semiconductor wafer, and a size detecting unit for detecting the size of the object to be inspected on an advancing / retreating path of the load tweezers near the alignment mechanism. Probe device.