JPH0736414B2 - Wafer prober microscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to improvement of a microscope attached to a wafer prober.

(B) Conventional technology On a wafer that has undergone the wafer process, semiconductor devices such as ICs are arranged and built in mesh chips. The chips on these wafers include defective chips caused by various causes. Therefore, the defective chip is selected by inspecting the electrical characteristics of each chip.

As a wafer prober used for this wafer inspection (wafer probing), a needle that contacts a chip on the wafer, a measurement circuit to which the needle is connected, and a defective chip are marked based on the measurement result of this measurement circuit. There is known a marking means for attaching a mark and a wafer drive mechanism for moving the wafer up and down and moving it chip by chip.

The wafer prober is provided with an optical microscope for confirming the contact state between the chip and the needle. The conventional microscope for a wafer prober has substantially the same configuration as that of a general optical microscope, and includes an objective lens, an eyepiece lens, a lens barrel, and the like.

(C) Problems to be solved by the invention As the wafer prober continues to inspect wafers,
An error occurs in the selection of good or bad chips due to an abnormality in the needle or measuring circuit. Therefore, it is necessary to inspect the wafer prober itself. This inspection is performed according to the following procedure.

First, the reference wafer is loaded into the wafer prober. The reference wafer is one in which one wafer previously inspected by the wafer prober is stored, and a defective chip is marked.

Next, the needles are sequentially brought into contact with the chips on the reference wafer, and the electrical characteristics of the chips are measured.
At this time, the operator looks into the conventional wafer prober microscope to check whether or not the chip has a defect mark. Next, the operator confirms the measurement result displayed on the operation unit of the wafer prober.

If the measurement result is bad even if the chip is not marked with a bad mark, or if the chip is marked with a bad mark and the measurement result is good, then the measurement circuit of the wafer prober, etc. An abnormality has occurred.

However, in the above-described inspection of the wafer prober, the operator has to look at the wafer prober microscope and the operation portion of the wafer prober alternately, which is inconvenient and time-consuming.

The present invention has been made in view of the above-mentioned inconvenience, and an object thereof is to provide a microscope for a wafer prober that facilitates the inspection work of the wafer prober itself.

(D) Means for Solving Problems As a means for solving the above-mentioned inconveniences, the wafer prober microscope of the present invention is a chip on a wafer loaded in the wafer prober, and the needle of the wafer prober makes contact. Optical system for obtaining a magnified image of the chip being processed, display means for optically displaying the wafer inspection result of the wafer prober, and the display means via a beam splitter provided in the first optical system. A second optical system for displaying the image of 1) together with the magnified image of the chip.

(E) Action In the microscope for wafer prober of the present invention, the measurement result of the chip is displayed together with the enlarged image of the chip, so that the operator need only look into the microscope. Therefore, the inspection work of the wafer prober itself is facilitated and the time is shortened.

(F) Embodiment One embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a diagram showing an optical system of a wafer prober microscope (hereinafter, simply referred to as a microscope) 1 according to an embodiment of the present invention.

The microscope 1 is composed of a first optical system 2 and a second optical system 7. The first optical system 2 includes an objective lens 3, a half mirror (beam splitter) 4, an eyepiece lens 5, and a lens barrel 6. The objective lens 3 is supported by the lower end of the lens barrel 6, and the wafer W loaded in the wafer prober.
Capture the image of tip t (see FIG. 3). The light flux from the objective lens 3 travels upward in the lens barrel 6 and passes through the half mirror 4 (see FIG. 1). The light flux transmitted through the half mirror 4 further reaches the eyepiece lens 5. The operator can see an enlarged image of the tip t by looking into the eyepiece lens 5 with the naked eye e.

The second optical system 7 is composed of a shutter 8, a lens 9, a display plate 12 and a lens barrel 11. The lens barrel 11 is provided in the lens barrel 6, and its left end portion 11a communicates with the storage portion 6a of the half mirror 4 of the lens barrel 6.

A display plate 12 is provided at the right end 11b of the lens barrel 11. The display plate 12 is provided with display portions (display means) 14a, 14b, 14c illuminated from behind by light emitting diode elements (LEDs) 13a, 13b, 13c (first).
Only the LED 13b and the display section 14b are shown in the figure).

The display portions 14a, 14b, 14c are the cutout portions 12a of the display board 12.
Further, colorless and transparent or colored and transparent display plates 15a, 15b and 15c are mounted. The letters "PASS", "FAIL" and "SENSOR" are stamped on the display boards 15a, 15b, 15c,
These characters indicate the meaning of lighting of the display units 14a, 14b, 14c.

Behind the display plates 15a, 15b, 15c, the LEDs 13a, 13b, 13
c are located respectively. The LEDs 13a, 13b, 13c are connected to the measurement circuit 16 of the wafer prober, and the LEDs corresponding to the measurement result of the measurement circuit 16 are lit. LED13
Light from a, 13b, and 13c is transmitted through the display plates 15a, 15b, and 15c to illuminate the display units 14a, 14b, and 14c.

Light from the display units 14a, 14b, 14c travels leftward in the lens barrel 11 and passes through the lens 9 (see FIG. 1). The light transmitted through the lens 9 is reflected by the half mirror 4, travels upward in the lens barrel 6, and enters the eyepiece lens 5. In this way, the images of the display units 14a, 14b, and 14c are displayed together with the enlarged image of the wafer (see FIG. 3). The shutter 8 is for blocking light from the display units 14a, 14b, 14c so that the images on the display units 14a, 14b, 14c are not visible except when the wafer prober is inspected.

The wafer W is supported on a wafer drive mechanism (not shown) in the wafer prober. The wafer drive mechanism has a function of moving the wafer W in a horizontal plane so that the chips on the wafer W are sequentially positioned immediately below the objective lens 3. Further, the wafer drive mechanism moves the wafer W up and down,
It also has a function of bringing the tip t into contact with the tips of the needles 17 ,.

The needles 17, ..., 17 are supported by a ring 18 horizontally supported and fixed between the lower side of the eyepiece 3 and the wafer W.
The needles 17, ..., 17 are respectively connected to the measuring circuit 16.

Next, an example of use of this microscope 1 will be described below.

When it is considered that an abnormality has occurred in the wafer prober, the reference wafer W is loaded in the wafer prober and the shutter 8 is opened.

Then, each chip t of the wafer W is moved by the wafer drive mechanism.
Sequentially move to the lower side of the objective lens 3, and the needle 17, ...
Touch 17 together. During this time, the operator is looking through the eyepiece lens 5. An image transferred to the naked eye e of the operator is shown in FIG. 3 (a shaded portion in FIG. 3 indicates that the portion is dark).

, 17 are brought into complete contact with the tip t, and when the measurement is possible, the measuring circuit 16 detects this and turns on the LED 13c. When the LED 13c is turned on, the display portion 14c shines and is displayed together with the enlarged image I of the chip t (see FIG. 3). Whether or not the needles 17, ..., 17 are abnormal can be checked by looking at the eyepiece lens 5 based on the presence or absence of the display on the display unit 14c.

When the needles 17, ..., 17 are completely in contact with the tip t and the display portion 14c is displayed, the measuring circuit 16 measures the electrical characteristics of the tip t. When the measurement result is “good”, the LED 13a is turned on and the display unit 14a is displayed. On the other hand, when the measurement result is “defective”, the LED 13b is turned on and the display unit 14b is displayed.

The defective chip t on the reference wafer W is marked with a defective mark m. When the chip t marked with the defective mark n is measured, the display section 14b is displayed (see FIG. 3), and the chip t not marked with the defective mark n is displayed.
When the display unit 14a is displayed when the measurement is performed, it means that the measurement circuit 16 has no abnormality.

On the contrary, when the display section 14a is displayed when the chip t with the defective mark m is measured, or when the display section 14b is displayed when the chip t without the defective mark m is measured, An abnormality has occurred in the measurement circuit 16.

The operator confirms the presence or absence of the defect mark m on each chip t and the display of the display units 14a and 14b while removing the eyepiece 5. If there are many false displays on the display 14a, 14b,
Readjustment and repair of the measurement circuit 16 are performed.

When the wafer prober is in the normal wafer inspection state,
The shutter 8 of the microscope 1 is closed to function as a conventional wafer prober microscope.

In the above embodiments, both the first optical system and the second optical system have the simplest configurations, and half mirrors are shown as the beam splitter, but the present invention is not limited to these and may be appropriately. The design can be changed.

Further, in the above embodiment, the transparent display plate illuminated from behind is used as the display means, but the present invention is not limited to this, and the design can be changed appropriately.

(G) Effect of the Invention A wafer prober microscope according to the present invention comprises a first optical system for obtaining an enlarged image of a chip on a wafer loaded in the wafer prober, the chip being in contact with a needle of the wafer prober. Display means for optically displaying a wafer inspection result of the wafer prober, and second optical means for displaying an image of the display means together with an enlarged image of the chip via a beam splitter provided in the first optical system. Since the system includes the system, it has an advantage that the inspection work of the wafer prober itself can be performed easily and in a short time.

[Brief description of drawings]

Each of the drawings shows an embodiment of the present invention, FIG. 1 shows an optical system of a wafer prober microscope according to the embodiment, and FIG. 2 shows a display plate of the wafer prober microscope. FIG. 3 is a front view and FIG. 3 are diagrams showing an enlarged image of a chip on a wafer and an image of a display unit obtained by the same microscope for a wafer prober. 2: First optical system, 4: Half mirror, 7: Second optical system, 14
a ・ 14b ・ 14c: Display, W: Wafer, t: Chip.

Claims (1)

[Claims] 1. A magnified image of a chip on a wafer loaded in a wafer prober, which is in contact with a needle of the wafer prober, is optically detected by a first optical system and a wafer inspection result of the wafer prober is optically obtained. A wafer prober microscope comprising: display means for displaying; and a second optical system for displaying an image of the display means together with an enlarged image of the chip via a beam splitter provided in the first optical system.