JPH0719811B2 - Wafer inspection method using a probe device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wafer inspection method using a probe apparatus for measuring the electrical characteristics of a chip formed on a semiconductor wafer.

[Prior Art] Generally, in an auto-prober apparatus, as shown in FIG.
When set to 01 and register the type, cassette 10 is automatically
The wafer 1 is taken out from within 3 and mounted on the chuck 21.
Then, course alignment and wafer thickness measurement are performed by the alignment stage 102 and the like, and the chuck 21 is moved to the center of the XY stage 100 for measurement. At this time, for the first wafer to be measured, as shown in FIG. 4, the chuck 21 is moved up to the probe needle 11 side, and then finely adjusted in the θ direction and in the XY direction by the microscope, and then, as shown in FIG. Thus, the electrode 3 of the chip 2 and the probe needle 11 are aligned with each other.

[Problems to be Solved by the Invention] As described above, in the conventional prober, the needle alignment of the probe needle and the tip is performed by an operator using a microscope, and its operation requires skill and much time. Was.

An object of the present invention is to enable automatic needle alignment between a probe needle and a tip electrode, which has been difficult to automate in an automatic probe device, and to realize a fully automatic probe device.

[Means for Solving the Problems] In order to achieve such an object, the needle alignment method of the present invention uses the probe so that the arrangement direction of the chips and the probe card are aligned before the alignment of the wafer to be inspected. The card is adjusted in the direction of rotation, then the alignment of the wafer is adjusted and the amount of rotation of the wafer at this time is stored, and then the probe card is rotated by the same amount as the stored amount of rotation, and then the probe is rotated. The wafer is adjusted in the horizontal direction so that the needle is aligned with the electrode of the chip, and then the wafer is inspected.Furthermore, the alignment of the chips and the rotation direction of the probe card are adjusted and the horizontal direction is adjusted. The adjustment of the direction is performed after the wafer is brought close to the probe needle based on a distance between the wafer and the probe needle that is stored in advance. It

[Examples] Hereinafter, the inspection method of the present invention will be described based on Examples shown in the drawings.

FIG. 1 shows an outline of a probe apparatus to which the present invention is applied. Mainly, a probe card unit 10 connected to a tester (not shown) and provided with probe needles, a wafer are placed, and a wafer is moved according to an inspection program. It comprises a stage 20, an image processing unit 30 for positioning and the like, and a central control unit 40 for outputting an inspection program.

The probe card unit 10 is provided at substantially the center of the head plate of the prober device, has a probe card 12 having probe needles 11 attached thereto, and has a mechanism for rotating the probe card 12 in the θ direction.

The stage 20 includes a wafer mounting table 21 on which the wafer 1 is mounted, a step motor 23 for driving the wafer mounting table 21 in the direction of the support shaft 22 (Z direction), and the wafer mounting table 21 on the X rail (not shown) and the Y rail (see FIG. It consists of an X-axis drive motor 24 and a Y-axis drive motor 25 for moving along (not shown).

The image processing unit 30 is an IT installed above the probe card unit 10.
It is composed of a V camera 31 and a monitor unit 32, and the monitor unit 32 is connected to the central control unit 40.

The central control unit 40 includes a θ rotation mechanism of the probe card unit 10 and a control unit 41 that controls the drive of the step motor 23, the X-axis drive motor 24, and the Y-axis drive motor 25 of the stage 20, and a memory 42 that stores the drive amount. .

The relationship between the wafer 1 and the probe card 12 and the positional relationship between the electrode 3 of the chip 2 and the probe needle 11 are as shown in FIGS. 4 and 5.

Next, the alignment method of the present invention having such a configuration will be described. FIG. 2 is a flow chart diagram thereof.

First, when the probe card 12 is attached to the probe card unit 20 prior to the measurement, the step motor 23 is driven to raise the chuck top 21 in the Z direction until it contacts the probe needle 12. At this time, the distance h from the reference position (the position on which the wafer is mounted) on the upper surface of the wafer mounting table 21 to the probe needle 12 is obtained from the driving amount of the step motor 23 (movement amount of the chuck top 21) and stored in the memory 42.

Next, when the measurement start button is pressed, the wafer 1 is transferred from the transfer section and set on the wafer mounting table 21 at the load position.

Here, the thickness of the wafer is measured.

At this time, the measured wafer thickness d is stored in the memory 42 of the central controller 40.

Next, the wafer 1 is moved under the probe card unit 10 before the alignment, and is raised in the Z direction until just before the wafer 1 contacts the probe needle 11. The drive amount (Z ₁ ) in the Z direction at this time is automatically determined from h and d stored in the memory 42. Here, h is the height from the reference position of the wafer mounting table to the probe needle, and d is the thickness of the wafer. That is,
Z ₁ is a value slightly smaller than (h−d) (a predetermined amount of about 10 μm).

In this manner, with the wafer 1 and the probe needle 11 approaching each other, the image processing unit 30 aligns the wafer 1 and the probe card, that is, the probe 1 so that the street line 2a of the wafer 1 and the θ direction of the probe card 12 coincide with each other. Card 12
Adjust the θ rotation mechanism.

Next, the wafer mounting table 21 is lowered to the reference position and moved to the alignment stage for alignment. That is, the θ axis of the wafer mounting table 21 is aligned so that the orthogonality between the street lines 2a and the X and Y rails has a predetermined accuracy.
The amount of θ rotation (θ ₁ ) of the wafer mounting table 21 at this time is stored in the memory
Store in 42.

The wafer 1 after the alignment is moved again to the probe card unit 10 and raised in the Z direction. The drive amount at this time is the same as the previous drive amount (Z ₁ ). Then, the probe card 12 is rotated by the same amount as the θ rotation amount (θ ₁ ) of the wafer mounting table 21 on the alignment stage. As a result, the probe card 12 and the street line 2a of the wafer 1 coincide with each other.

Next, while monitoring by the image processing unit 30, the X-axis drive motor 24 and the Y-axis drive motor 25 are drive-controlled so that the probe needle 11 and the electrode 3 of the tip 2 coincide with each other this time. When the probe needle 11 and the electrode 3 coincide with each other as shown in FIG. 5, the probe needle 11 and the stage 21 are relatively moved, for example, the wafer mounting table 21 is raised by a predetermined amount, and the measurement preparation is completed. From this, a predetermined inspection, for example, a 5-point check and measurement are started. That is, an electric signal is output from the tester, the output signal from the electrode pad is detected, and the output signal is compared with an expected value stored in advance for inspection.

[Effect] As is clear from the above description, in the wafer inspection method of the present invention, the θ of the probe card is adjusted with the street line of the wafer prior to alignment, and the wafer (mounting table) during alignment is adjusted. Since the amount of rotation is stored and the probe card is rotated by the stored amount of rotation when the wafer is aligned with the needle, the needle alignment of the wafer only needs to be adjusted in the X and Y directions. Can be done. Further, since the distance between the probe needle and the wafer mounting table is measured and stored in advance, it is possible to automatically bring the wafer close to the probe needle to a desired position based on the stored distance during θ adjustment and XY adjustment. .

[Brief description of drawings]

FIG. 1 is a schematic diagram of a probe device for applying the present invention, FIG. 2 is a flow chart diagram showing an embodiment of the present invention, FIG. 3 is a plan view of the probe device, and FIG. 4 is a wafer and a probe needle. FIG. 5 is a view showing the electrodes of the chip and the probe needle. 1, 21 ... Wafer 10, 12 ... Probe card 11 ... Probe needle 20 ... Stage 23 ... Step motor 30 ... Image processing unit 31 ... ITV camera 32 ... Monitor unit 40 ... Central control unit 41 ...... Drive control unit 42 …… Memory

Claims (2)

[Claims] 1. Prior to alignment of a wafer to be inspected, the probe card is adjusted in a rotating direction so that the arrangement direction of the chips and the probe card are aligned with each other, and then alignment adjustment of the wafer is performed. After storing the amount of rotation of the wafer and then rotating the probe card by the same amount as the stored amount of rotation, the wafer was adjusted horizontally so that the probe needle and the electrode of the chip were aligned. A method of inspecting a wafer by a probe device, which comprises performing an inspection of the wafer after that. 2. The adjustment of the chip arrangement direction and the rotation direction of the probe card and the horizontal adjustment are performed by bringing the wafer close to the probe needle based on a distance between the wafer and the probe needle stored in advance. The method for inspecting a wafer by a probe device according to claim 1, which is performed later.