JPH05343485A - Wafer inspecting apparatus - Google Patents

Abstract

PURPOSE:To obtain a wafer inspecting apparatus wherein, even when the type of a wafer is changed, it is not required to newly acquire a reference pattern and a movement amount by a method wherein the reference pattern and the movement amount up to an inspection position, which have been read out, are used in an alignment adjustment part. CONSTITUTION:According to the type of a wafer 22 as an object, under test, which has been selected by means of a keyboard 34, a hard disk device 32 reads out the following from a storage means: reference data corresponding to the wafer 22; and movement-amount data up to an inspection position. The reference data and the movement-amount data which have been read out are written respectively into RAMs 26, 30 in an image processing device 24 and a prober control part 28. The image processing device 24 and the prober control part 28 align the wafer 22 on the basis of the reference data and the movement- amount data. Thereby, the wafer can be inspected with good efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer inspection apparatus,
In particular, the present invention relates to a wafer inspection device for inspecting the electrical characteristics of semiconductor element circuits formed in large numbers on a semiconductor wafer.

[0002]

2. Description of the Related Art A semiconductor wafer has a large number of identical electric element circuits formed according to the type of wafer, and it is necessary to inspect the formation quality of each electric element circuit before cutting the electric element circuit into each chip. The pass / fail of each electric element circuit is determined by the powe card of the wafer inspection device.

When inspecting wafers of the same type, the wafer inspection apparatus performs alignment adjustment on the first wafer, and based on this result, the electrode pads of the element circuits of the second and subsequent wafers are the same as those of the probe card. It is designed to surely contact the probe needle. That is, in the alignment adjusting method, as shown in FIG. 2, first, a first wafer 3 is sucked onto a table 2 provided movably on the wafer inspection apparatus body 1, and the table 2 is placed under the CCD camera 4. To the specified position.

Next, of the array patterns of a plurality of element circuits formed on the wafer 3, a reference pattern serving as a reference is picked up by the CCD camera 4, and the reference pattern is stored in the RAM 5a of the image processing apparatus 5 as model data. Remember. Next, the table 2 is moved in the direction of the probe card 6, the probe needle 7 of the probe card 6 is brought into contact with the electrode pad of the wafer 3, and the amount of movement L to the contact (inspection) position is controlled by the prober. Part 8 R
It is stored in the AM 8a. Then, the first wafer 3
Inspects each element circuit based on the position where the probe needle 7 is in contact with the electrode pad.

Regarding the second and subsequent wafers 3, first,
The table 2 is moved using a known correlation method or the like so that the CCD camera 4 images the same circuit pattern as the reference pattern of the model data stored in the RAM 5a. Next, the table 2 is moved by the moving amount L stored in the RAM 8a. As a result, the second and subsequent wafers 3
Also, the probe needle 7 is moved to a position where the electrode pad abuts. In this way, the alignment of the second and subsequent wafers 3 is adjusted based on the model data stored in the first wafer 3 and the movement amount.

[0006]

However, in the conventional alignment adjusting method for the wafer inspection apparatus, for example, when the wafer of the type A is inspected and then the wafer of the type B is inspected, the reference pattern of the type A previously inspected, And the amount of movement to the inspection position is erased from the RAMs 5a and 8a,
When re-inspecting the wafer of the type A, the reference pattern and the amount of movement to the inspection position must be newly acquired, so that the wafer cannot be inspected efficiently.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wafer inspection apparatus that does not need to newly acquire a reference pattern and a movement amount even if the type of wafer is changed.

[0008]

In order to achieve the above object, the present invention provides a wafer based on an image pickup means for picking up an image of a circuit pattern on a wafer, and a reference pattern of the wafer picked up by the image pickup means and stored in advance. Automatically aligns the wafer to a predetermined position and moves the aligned wafer by the amount of movement of the wafer stored in advance to the inspection position of the wafer, and a probe card. In a wafer inspection device comprising an inspection unit for inspecting with the probe card, storage means capable of holding stored contents without backup, and storing the reference pattern and the amount of movement to the inspection position for each wafer type Means for instructing writing and reading to the means, and corresponding to the wafer from the storage means according to the kind of the wafer. To reference pattern, and reading the amount of movement to the inspection position, characterized in that the amount of movement to the reference pattern and the inspection position readout was for use in the alignment portion.

[0009]

According to the present invention, storage means capable of holding storage contents without backup and means for writing and reading the reference pattern and the amount of movement to the inspection position in the storage means for each type of wafer. Is provided in the wafer inspection apparatus, and the reference pattern corresponding to the wafer and the amount of movement to the inspection position are read from the storage unit according to the type of the wafer to be inspected, and the read reference pattern and the inspection position are read. Was used in the alignment adjustment section of the wafer inspection apparatus.

As a result, even if the type of the wafer is changed, it is not necessary to newly acquire the reference pattern of the wafer and the movement amount to the inspection position, so that the wafer can be inspected efficiently.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a wafer inspection apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. In Figure 1,
An embodiment of a wafer inspection apparatus 10 according to the present invention is shown.
A probe card 14 is attached to the head stage 12 of the wafer inspection apparatus 10, and a plurality of probe needles 16, 16 ... As wafer inspection gauges are fixedly attached to the probe card 14. Also,
A CCD camera 18 is installed on the head stage 12 at a predetermined position with respect to the probe card 14. Further, a moving table 20 is arranged below the head stage 12, and a wafer 22 to be inspected is sucked onto the upper surface of the table 20.

On the other hand, an image processing device 24 is connected to the CCD camera 18. This image processing device 24 is
A predetermined circuit pattern of the wafer 22 (a specific pattern including a plurality of circuit elements and streets, which is a pattern that is easily aligned) imaged by the D camera 18 is image-processed to create model data, and the model data is generated. Is R
The table 20 can be moved using a known correlation method or the like so as to match the reference data temporarily stored in the AM 26. The reference data will be described later.

A prober controller 28 is connected to the image processing device 24. The prober control unit 28 is a RAM
30. The table 20 can be moved in the direction of the probe card 14 based on the movement amount data to the inspection position of the table 20 temporarily stored in the RAM 30. By moving the table 20 based on the movement amount data, the probe needles 16 of the probe card 14 are attached to the electrode pads of the wafer 22.
16 ... Abut. The movement amount data will be described later.

A hard disk device 32 is connected to the image processing device 24 and the prober controller 28, and the hard disk device 32 is installed in the wafer inspection device 10. The hard disk device 32 has storage means capable of holding storage contents without backup, and means for writing and reading the above-mentioned reference data and movement amount data to the inspection position in the storage means for each wafer type. And are provided. Further, the hard disk device 32 reads the reference data corresponding to the wafer and the movement amount data to the inspection position from the storage unit according to the kind of the wafer to be inspected selected by the keyboard 34, and the read reference data. The data and the movement amount data are transferred to the image processing device 24 and the prober control unit 28.
Can be written in the RAMs 26 and 30, respectively.

Next, a method for adjusting the alignment of the wafer 22 by the wafer inspection apparatus 10 configured as described above will be described. First, before starting the inspection, the type of the wafer 22 to be inspected is selected by the keyboard 34, the reference data corresponding to the wafer 22 and the movement amount data to the inspection position are read from the storage means of the hard disk device 32, The read reference data and movement amount data are written in the RAMs 26 and 30, respectively.

Next, a probe card corresponding to the inspection target wafer 22 is set. This probe card is attached by a mechanism in which the attachment position as described in, for example, Utility Model No. 3-38833 is reproduced with sufficient accuracy. Next, the wafer 22 is attracted to the table 20, and the table 20 is moved to a predetermined position below the CCD camera 4.

Next, the circuit pattern (pattern including a plurality of circuit elements and streets) of the wafer 22 picked up by the CCD camera 18 is image-processed by the image processing device 24 to successively create model data. Then, the table 20 is moved to a position where the model data matches the reference data written in the RAM 26 by using a known correlation method or the like.

Next, the table 2 is read from the matched position.
0 is moved by the moving amount L based on the moving amount data to the inspection position written in the RAM 30 of the prober control unit 28. As a result, the wafer 22 moves to the position where the electrode pads contact the probe needles 16, 16 ...
Then, the table 20 is sequentially moved according to the size of the element circuit of the wafer 22 with reference to the contact position, and each element circuit of the wafer 22 is inspected.

Next, when inspecting a wafer of a different type from the wafer 22, the type of the wafer is selected with the keyboard 34, and the reference data corresponding to the wafer and the inspection from the storage means of the hard disk device 32 are selected. The movement amount data up to the position may be read, and the read reference data and movement amount data may be written in the RAMs 26 and 30, respectively. (At this point, RAM 26, 3
The reference data and the movement amount data of the wafer 22 stored in 0 are erased. By this, the wafer can be inspected without acquiring the wafer reference data and the movement amount data to the inspection position.

When inspecting the wafer 22 of the same type as the first inspected wafer 22 after the inspection of the wafer,
The reference data of the wafer 22 and the movement amount data to the inspection position need only be written in the RAMs 26 and 30, respectively. Therefore, according to the present embodiment, the position of the probe card to be replaced when switching the type of wafer is reproduced sufficiently accurately as described above, so that the inspection target is changed every time a wafer of a different type is inspected. Compared with the conventional wafer inspection apparatus that must acquire the wafer reference data and the movement amount data to the inspection position, the wafer inspection can be performed efficiently.

In this embodiment, a CCD is used as the image pickup means.
Although the camera 18 is used, it is not limited to this,
It may be a microscope or other solid-state image sensor. Further, in the present embodiment, the hard disk device 32 is used, but the hard disk device 32 is not limited to this, and a floppy disk device or a PROM (programmable-RO) that can be rewritten any number of times.
You may use the apparatus provided with M).

[0022]

As described above, according to the wafer inspection apparatus of the present invention, the storage means capable of holding the stored contents without a backup, and the reference pattern and the movement amount to the inspection position for each wafer type are described above. The storage means is provided with means for instructing writing and reading, and the reference pattern corresponding to the wafer and the amount of movement to the inspection position are read from the storage means according to the type of wafer to be inspected. The read reference pattern and the amount of movement to the inspection position are used by the alignment adjustment unit of the wafer inspection apparatus. As a result, even if the type of wafer is changed, it is not necessary to newly acquire the reference pattern of the wafer and the amount of movement to the inspection position, so that the wafer can be efficiently inspected.

[Brief description of drawings]

FIG. 1 is an explanatory view of an embodiment of a wafer inspection apparatus according to the present invention.

FIG. 2 is an explanatory view showing an embodiment of a conventional wafer inspection device.

[Explanation of symbols]

 10 ... Wafer inspection device 14 ... Probe card 18 ... CCD camera 20 ... Table 22 ... Wafer 24 ... Image processing device 26, 30 ... RAM 28 ... Prober control unit 32 ... Hard disk device

Claims (1)

[Claims] 1. An image pickup means for picking up an image of a circuit pattern on a wafer, and the wafer is automatically aligned at a predetermined position based on a reference pattern of the wafer picked up by the image pickup means and stored in advance. A wafer inspecting apparatus comprising: an alignment adjusting unit for moving a stored amount of movement of a wafer to an inspection position; and an inspecting unit having a probe card for inspecting each circuit element of an aligned wafer with the probe card. A storage unit capable of holding stored contents without a backup, and a unit for writing and reading the reference pattern and the amount of movement to the inspection position in the storage unit for each type of wafer, Depending on the type of wafer, the amount of movement from the storage means to the reference pattern and inspection position corresponding to that wafer A wafer inspection apparatus, wherein the wafer is read and the read reference pattern and the movement amount to the inspection position are used in the alignment adjustment unit.