JPH0337650A - Defect checking device for mask reticle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] This invention relates to the improvement of a device for inspecting defects in masks and reticles used in the manufacture of semiconductor devices.
Inspecting masks and reticles for defects with high precision to prevent defects from occurring in the pattern of the resist layer formed by exposure and development using light with a wavelength range selected from the wavelength range of 00nm to 190nm. The purpose of the present invention is to provide a device that can emit light, and includes a light emitting source, an optical system that converts the emitted light from the light emitting source into two parallel beams, and a filter provided on the optical axis of each of the two parallel beams. An
- An objective lens provided to face each of the two parallel beams incident on the object to be inspected placed on the Y stage, and an optical system that detects the two parallel beams received by the objective lens. A mask having a light detection means for detecting the light through the
In the reticle defect inspection device, the filter is
It is configured to transmit light having a wavelength range selected from the wavelength range of 400n- to 190rv of the light emitted from the light emitting source.

[Industrial Field of Application] The present invention relates to an improvement in an apparatus for inspecting defects in masks and reticles used in the manufacture of semiconductor devices.

[Prior Art] See Fig. 1 Fig. 1 is a schematic diagram showing the structure of a defect inspection device for a mask/reticle 5.6 The emitted light from a mercury lamp 1, which is a light emitting source, is emitted by an optical system consisting of a mirror and a lens. The system 3 converts the light into two parallel beams 2, which are incident on a mask or reticle 5 placed on an XY stage 6. In this case, the two parallel beams 2 are separately incident on two patterns among the plurality of patterns formed on the mask or reticle 5. The two parallel beams 2 that have passed through the mask or reticle 5 are received by an objective lens 7, and each is detected by a light detection means 9 such as an image sensor via an optical system 8. By moving the X-Y stage 6, 2
The entire area of the two patterns formed on the mask/reticle 5 is scanned with the parallel light 2 of the stripes, and the information obtained by the image sensor 9 is image-processed.
Defect areas are detected by comparing images of two patterns.

Conventionally, defects are inspected by using a filter 4 that transmits light in a visible light range close to green, and by irradiating light in a visible light range close to green or visible light without using a filter. .

(Problems to be Solved by the Invention) As semiconductor devices become faster and more highly integrated, their structures tend to become increasingly finer.Therefore, fine patterns formed on masks and reticles are being transferred onto semiconductor substrates. High resolution is now required in the exposure process for transferring onto the resist layer formed on the resist layer.For this reason, instead of the g-line (wavelength 436n-) of mercury lamp light, which was conventionally used as the irradiation light for exposure, Therefore, the 1-line (wavelength ff65n+s) of mercury lamp light, which has a shorter wavelength, for example, has come to be used.

However, when the mask/reticle was inspected using visible light in the green region and no defects were found, the resist layer was exposed and developed using a single line of mercury lamp light. A phenomenon in which defects occur in patterns transferred to the

The purpose of the present invention is to eliminate this drawback, and to provide a resist layer formed by exposure and development using light having a wavelength range selected from the wavelength range of 400ne to 190ne, such as the l-ray of a mercury lamp. An object of the present invention is to provide an apparatus capable of inspecting defects in a mask/reticle with high accuracy so that defects do not occur in the pattern of the mask/reticle.

[Means to solve the problem]

The above purpose is to provide a source (1), an optical system (3) that converts the emitted light of this source (1) into two parallel beams (2),
A filter (4) is provided on the optical axis of each of the two parallel beams (2), and a filter (4) is provided facing the two parallel beams (2), on which the object to be inspected (5) is placed. The X-Y stage (6) is provided opposite to each of the two parallel beams (2) that are incident on the object to be inspected (5) placed on the X-Y stage (6). an objective lens (7) that is
) through an optical system (8). This is accomplished by a mask/reticle defect inspection device that transmits light in a wavelength range selected from the -190 nm wavelength range.

[Effect]

The mask/reticle was inspected using light in the visible green range, and no defects were detected.
When developing, when exposing and developing by irradiating the g-line of a mercury lamp, no defects are formed in the pattern of the formed resist layer. When irradiating, exposing and developing,
The occurrence of defects in the pattern of the formed resist layer means that the light absorption coefficient of the defective part of the mask/reticle,
This is because the refractive index and other factors differ depending on the wavelength, so defects that originally existed in the mask/reticle and were not a problem when exposed with the G-line form an image on the resist layer when exposed to the I-line. I figured it out.

Therefore, in the mask/reticle defect inspection apparatus according to the present invention, by inspecting the mask/reticle for defects using light having the same wavelength as that used during actual exposure, problems can be detected during exposure. We decided to eliminate this problem by removing defects in the mask reticle.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A mask/reticle defect inspection apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

Refer to Figure 1 again. Figure 1 is a schematic diagram showing the configuration of a mask/reticle defect inspection device. 4 is a filter that transmits only one line of light from a mercury lamp, 6 is an X-Y stage on which a mask or reticle 5 is placed, and 7 is a filter with two parallel stripes. An objective lens is provided to face the light 2 , and 8 is an optical system that guides an image received by the objective lens 7 to an image sensor 9 .

A mask or reticle 5 is placed on an X-Y stage 6, and a plurality of patterns are formed on the mask or reticle 5 using two parallel beams 2 having a width corresponding to the width that can be received by the image sensor 9. The X-Y stage 6 is moved so as to scan each of the two patterns in the image.

Refer to Figure 2. The image processing means 10 processes the information received by the two image sensors 9, and the defect detection means 1X compares the two pattern images, and determines the different areas of the two images as defects. and stored in the defect memory 12.

After scanning all the patterns formed on the mask or reticle, the X-Y stage 6 is moved so that the parallel light 2 enters the defect area stored in the defect memory 12, and the visual optical system (not shown) is moved. Inspect the defective area in detail using Note that at this time, the filter 4 is replaced with a visible light filter. Furthermore, it is also possible to display the image-processed pattern copy using i-line and visible light on a CRT, and inspect this image for defects.

In addition, in the example, the case of irradiation with i-line of mercury lamp light was explained, but excimer laser (wavelength 24
It has been confirmed through experiments that it is also effective when irradiating light with a wavelength selected from the wavelength range of 400 nm to 190n11, such as argon fluorine laser (wavelength 193rv).

(Effects of the Invention) As explained above, the mask/reticle defect inspection apparatus according to the present invention inspects defects in the mask/reticle using light having the same wavelength as the light used during exposure. All defects, which sometimes cause problems, could be detected, making a significant contribution to improving the reliability of photolithography for semiconductor devices with fine patterns.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a mask/reticle defect inspection apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing the flow of defect detection.・Water pump, ・Parallel light, ・Optical system, ・Filter, ・Object to be inspected (mask/X-Y stage, ・Objective lens, ・Optical system, ・Light detection means (image sensor) ・Reticle),

Claims (1)

[Claims] A light emitting source (1), an optical system (3) that converts the emitted light of the light emitting source (1) into two parallel beams (2), and the two parallel beams (2). a filter (4) provided on each of the optical axes of the two parallel beams (2); an objective lens (7) provided to face each of the two parallel beams (2) incident on the object to be inspected (5) placed on the X-Y stage (6); and the objective lens. (7)
In the mask/reticle defect inspection apparatus, the mask/reticle defect inspection apparatus includes a light detection means (9) for detecting the two parallel beams (2) received by the filter via an optical system (8). 4 of the radiation of source (1)
A mask/reticle defect inspection device characterized by transmitting light having a wavelength range selected from a wavelength range of 00 nm to 190 nm.