JPS6019138B2 - Development status inspection method in photoetching - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a development state inspection method in photoetching.

There may be various inspections during a series of photoetching steps, one of which is an appearance inspection after development, that is, an inspection of the development state.

In the case of semiconductor wafers, this development condition inspection is 100 to 40
A method that relies on visual inspection using a metal microscope with a magnification of about M-sound is often used. In any case, since it is a visual inspection using a microscope, this inspection method is not only undesirable for automating a series of steps in semiconductor device manufacturing, but also tends to overlook defective products or damage the wafer. There is a drawback. The object of the present invention is to provide a method for inspecting the development state in photoetching which is free from such drawbacks and is also suitable for automation.

According to the present invention, this purpose is to apply a photoresist containing a photoresist to the surface of the wafer to be etched, apply a photomask thereon, expose the photoresist, and then develop the sample.The developed image of the sample is then irradiated with light. This is achieved by detecting a pattern of only the crab light component by passing the reflected light through a filter, and comparing the detected pattern with the pattern of the photomask to inspect the development state of the sample. .

It is desirable to use basic dyes such as Rhodamine B (C23 Day 3, CIN203) and Rhodamine 6G as the material for the photoresist to be included in the photoresist.

Next, the present invention will be explained in more detail with reference to the drawings. In FIG. 1, numeral 11 is a wafer to be photo-etched, which has a semiconductor layer, its oxide film, and the like.

The surface of the wafer 11 is coated with a photoresist containing the above-described photoresist to form a photoresist layer 12.
A photomask 13 having a predetermined pattern formed thereon is placed on the photoresist layer 12 and exposed photographically, and then the photoresist layer 12 is subjected to a photochemical development process. As a result, a pattern 12a corresponding to the pattern 13a of the photomask 13 is formed on the photoresist layer 12. Note that although the figure shows a type of photoresist layer 12 in which the portion exposed to light is dissolved by development,
This is just an example, and the present invention is also applicable to the opposite type. This is because, when comparing patterns to be described later, if necessary, the genitals and intestines of either the photomask 13 or the photoresist layer 12 may be optically or electrically inverted. This post-development process is the subject of the present invention. As shown in FIG. 2, a light source 21 is placed on the developed photoresist layer 12.
The reflected light is received by a photoelectric conversion light receiving section 23 through a filter 22 that passes only the crab light component, and its electrical output is inputted to one input device of a comparison/discrimination section 24.
An electric signal obtained by illuminating the photomask 13 with the light source 26 and transmitting the light through the photoelectric conversion light receiving section 27 is input to the other input terminal of the comparing and determining section 24 . Both photoelectric conversion light-receiving parts 23 and 27 correspond to the pattern of the portion of the photoresist layer 12 that remains after development and the photomask 13, respectively.
An electrical signal corresponding to the pattern is input to the comparison/determination section 24'. The comparison/determination unit 24 compares both electrical outputs and determines whether the former pattern signal deviates from the latter pattern signal by more than a predetermined deviation.
It is determined whether or not there is a defect in the developed state of the upper photoresist layer 12, and the determination result is displayed and recorded on the display/recording device 28, and when it is determined that there is a defect, the defect signal is sent to the elimination device 29. to remove them from the line. As described above, according to the present invention, by impregnating a photoresist with a photoresist and further using a filter, it is possible to fully automatically inspect the development state optically and electrically. Moreover, since there is no need for visual inspection, defective products cannot be overlooked and damage to wafers can be kept to a minimum.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining a photoetching process according to the present invention. FIG. 2 is a block diagram of an apparatus implementing the method of the invention. 11...Wafer, 12...Photoresist layer containing crab optical agent, 13...Photomask, 21, 26...,
．． ．． Light source, 22... Crab light filter evening, 23, 27
. . . Photoelectric conversion light receiving section, 24 . . . Comparison/discrimination section. Car outside diagram 2

Claims (1)

[Claims] 1. Apply a photoresist containing a fluorescent agent to the surface of the wafer to be etched, apply a photomask over it, expose it to light, and then develop it.The developed image of the sample is irradiated with light, and the reflected light is passed through a filter. A method for inspecting the development state of the sample in photoetching, the method comprising: detecting a pattern of only fluorescent components, and comparing the detected pattern with the pattern of the photomask to inspect the development state of the sample.