JPH03108643A - Apparatus for inspecting metallic wiring for semiconductor device - Google Patents

Abstract

PURPOSE:To automatically measure sizes and the number of hillocks and identify their height and steepness by attaching a TV camera to an optical microscope and image-processing its signal output. CONSTITUTION:A TV camera 2 is fixed on top of an optical microscope 1, the signal output line 2a of the camera 2 is connected to an image processor 3, the signal output line 3a of the processor 3 is connected to a monitor TV 4, and a specimen 5 to be inspected is mounted on a specimen mount 6 and then inspected. If a magnification of the microscope 1 is set at low to widen a field of view while concentration contrast of a signal output A of the camera 2 is strengthened, hillocks 11 can be displayed in spots on the TV 4 wherein diameter sizes and the number of the spots are read by the processor 3 to be automatically measured in line. Or if a transparent insulation coating 15 is deposited on a metallic wiring 16 of the specimen 5 and displayed in a normal contrast at a high magnification, steep hillocks 11 and low hillocks 14 can be distinguished from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to metal wiring for semiconductor devices, and particularly to an apparatus for inspecting billrock on the surface of metal wiring.

[Conventional technology]

In the manufacturing process of semiconductor devices, metal wiring such as M wiring formed on the semiconductor device is subjected to temperature cycles during the manufacturing process, which causes protrusions due to thermal strain and recrystallization, which is a so-called billlock. be. When this bill lock occurs, it causes poor insulation between the wiring and between the eyebrows. This is particularly a problem in multilayer wiring structures.

Conventionally, the following methods have been used to inspect this building lock.

(1) The worker visually inspects the metal wiring using an optical microscope,
Measure the size (diameter seen from above) and number of billrocks. In particular, to accurately measure the size of a building rock, use a microscopic optical microscope, place a leveling scale in the field of view, move it in line with the image of the target building rock, and read its size.

(2) Use an electron microscope to examine the surface of the metal wiring diagonally or
Determine the size, height, and steepness of the building rock by observing it from the horizontal direction.

[Problem to be solved by the invention]

However, in the above-mentioned method for inspecting metal wiring of semiconductor devices, optical l! When using a J-microscope, an operator visually measures the size and number of billrocks, so there is a problem that individual differences and counting errors are likely to occur. Also,
There is a drawback that the height and steepness of the building rock cannot be determined.

When using an electron microscope, the height and steepness of the building rock can be determined, but damage is caused by the electron beam, and although it is good for sample destructive inspection, it is not suitable for in-line use. There are problems that take time.

The object of the present invention is to solve the above-mentioned problems, and to develop a semiconductor device for in-line use, which is capable of automatically measuring the size and number of billrocks, and also capable of determining the height and steepness of billlocks. An object of the present invention is to provide a metal wiring inspection device.

[Means to solve the problem]

In order to solve the above-mentioned problems, the metal wiring inspection apparatus for semiconductor devices of the present invention includes an optical microscope for observing the metal wiring of a semiconductor device to be inspected (hereinafter referred to as an object to be inspected); A television camera that images the surface of the metal wiring of the observed object to be inspected and a monitor television that displays this image are connected between the television camera and the monitor television, and the signal output of the television camera is connected to a television camera that increases the contrast of shading. and an image processing device capable of processing and projecting billrocks generated on the surface of the metal wiring imaged on the monitor television in the form of spots, and reading the diameter size and number of the spots. .

[Effect]

To measure the size and number of billrocks, use an optical mirror with low magnification (for example, When displayed, billrock appears in spots (as shown in Figure 2).
By reading the diameter size and number of spots using an image processing device, automatic in-line measurement becomes possible. In addition, after depositing a transparent insulating film on the object to be inspected, if the optical microscope is set to a high magnification, e.g. In this case, the outline of the building rock and the outline of the insulating coating are double or overlapped and appear thick (as shown in Figure 3 (+1)). By observing the outline of the building rock, it is possible to determine the height and steepness of the building rock. It becomes possible to judge the Note that in the case of a multilayer structure, an insulating film such as transparent Sio2 is generally deposited between the first layer and second layer wiring by low-temperature CVD, so there is no need to add any particular process.

〔Example〕

FIG. 1 is a system diagram of an embodiment of a metal wiring inspection apparatus for semiconductor devices according to the present invention. A television camera 2 is fixed on the top of the optical microscope 1, and the i= signal output line 2 of the television camera 2 is connected to the optical microscope 1.
Connect a to the image processing device F3.

Further, the signal output line 3a of the image processing device 3 is connected to the monitor television 4. The object to be inspected 5 is placed on the sample stage 6 of the optical I-microscope 1 for one-time inspection.

Figure 2 is an image of an example of a display produced by the metal wiring inspection system for semiconductor devices shown in Figure 1. Optical! g1? When the field of view is widened by setting the lA mirror 1 to a low magnification, e.g. It appears in spots. By reading the diameter size and number of spots using the image processing device t3, automatic in-line measurement becomes possible.

FIG. 3 (fat) is another example of an image obtained by this apparatus, and the mountain in the figure is a cross-sectional view of the object 5 to be inspected taken along the line AA in this image plane. After depositing a transparent insulating film 15 on the metal wiring 16 of the object to be inspected 5, as shown in FIG. Assuming that the contrast of device 3 is normal, when this surface is displayed, in the case of a tall, steep building rock as shown in 13a in the same figure),
As shown in 13 of a), the outline of the building rock and the outline of the insulating coating are displayed thickly, doubly or overlappingly.

On the other hand, in the case of a low building rock as shown at 14a in FIG. By observing the contours of these billrocks, the height of the billrocks,
It becomes possible to judge steepness. Note that in the case of a multilayer wiring structure, there is generally a low-temperature CV between the first layer and the second layer of metal wiring.
Since a transparent insulating film of 5t (h) is deposited by D, the height and steepness of the billrock can be determined in-line without any additional steps.

〔Effect of the invention〕

According to the present invention, optics for observing an object to be inspected! ! By attaching a television camera to the J-micro saw and processing its signal output with an image processing device, the diameter and number of building locks can be automatically measured without visual inspection by the operator.
Visual errors are completely eliminated and inspection time is reduced by 1 hour.
It decreased to below 710.

In addition, it is now possible to judge the height and steepness of a building rock, which was previously difficult to do inline.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an embodiment of the metal wiring inspection apparatus for semiconductor devices of the present invention, FIG. 2 is an explanatory diagram of an example of an inspection image by the metal wiring inspection apparatus for semiconductor devices of FIG. 1,
3rd ryJTa+ is an explanatory diagram of another example of an inspection image by the same device; FIG. 3: 8 image processing device 4: Monitor TV 5: Inspected object A; Signal output (of the TV camera)

Claims (1)

[Claims] 1) An optical microscope that observes the metal wiring of the semiconductor device to be inspected (hereinafter referred to as the object to be inspected), a television camera attached to this that images the surface of the metal wiring of the observed object to be inspected, and a display that displays this image. connected between this TV camera and the monitor TV,
The signal output from the television camera is processed to have a strong contrast between light and shade, so that the billrock that has formed on the surface of the metal wiring imaged on the monitor television is displayed in the form of spots, and the diameter size and number of these spots can be read. 1. A metal wiring inspection apparatus for semiconductor devices, characterized by comprising an image processing device capable of processing the metal wiring.