JP2919192B2 - Reticle cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reticle cleaning apparatus used in an exposure process in a semiconductor device manufacturing process, and more particularly to a reticle cleaning apparatus provided with a reticle foreign matter inspection mechanism.

[0002]

2. Description of the Related Art Conventionally, a reticle cleaning apparatus used in the field of manufacturing semiconductor devices generally jets pure water or mixed water of an antistatic material onto a cleaning surface of the reticle, and cleans the reticle with a brush or sponge material as cleaning means. A cleaning mechanism and a reticle wet by the cleaning mechanism are dried by IPA as a drying means.
It is composed of a drying mechanism for drying in a (isopropyl alcohol) vapor atmosphere, a mechanism for inspecting foreign matter adhering to the reticle surface after drying, and a reticle transport mechanism for connecting them.

[0003] This conventional reticle foreign matter inspection mechanism is shown in FIG.
As shown in FIG. 1, a laser mechanism 13 for irradiating the surface of the inspection reticle 4 with a laser beam at a certain angle α for scanning, and detecting and detecting reflected light (scattered light) from the reticle surface generated by the laser mechanism 13. And a photoelectric element 14 which can detect the presence or absence of the foreign matter 12 based on a change in the intensity of the reflected light (scattered light) from the reticle surface.

[0004]

In the conventional reticle cleaning apparatus, the brush or sponge material as a cleaning means is subjected to cleaning processing, so that the brush or sponge material wears and dust adheres to the reticle. Further, since the reticle is dried in a vapor atmosphere of IPA, when the vapor temperature is unstable, the reticle is in an undried state, and stains or the like occur.

[0005] The foreign matter inspection mechanism provided in this conventional reticle cleaning apparatus is a system that detects reflected light (scattered light) from the reticle surface by irradiating laser light, and therefore absorbs and transmits the irradiated laser light. It is difficult to detect stains or foreign substances such as transparent substances,
There is a problem that the semiconductor device is subjected to a patterning process having a defect by determining that the reticle after the foreign substance inspection is normal after the cleaning and using the reticle for the exposure process.

[0006]

SUMMARY OF THE INVENTION A reticle cleaning apparatus of the present invention includes a mechanism for inspecting foreign substances on a reticle after cleaning.
The reticle foreign matter inspection mechanism irradiates the entire surface of the reticle with illumination light having a wavelength used in the exposure process from one side of the reticle and scans the reticle, and captures a transmission image of the reticle pattern transmitted to the other side of the reticle. Means for performing image processing of the transmitted image, means for storing regularity condition data of the reticle pattern image, and comparing and comparing regularity condition data of the reticle pattern image preset for the transparent image. A means for performing inspection calculation processing to enable detection of foreign substances such as stains and transparent substances.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram to which an optical system for explaining a reticle foreign matter inspection mechanism used in Embodiment 1 of the present invention is added.

An optical system of a reticle foreign matter inspection mechanism used in the present embodiment includes an illumination light source 1 for irradiating an inspection reticle 4 reflected by a half mirror 3 on an inspection reticle 4 mounted on a reticle holding mechanism 5, and illumination from the light source 1. A filter 2 provided on the optical path of the irradiated illumination light for extracting only the wavelength used in the exposure step, and a CCD camera or the like for capturing a pattern transmission image of the inspection reticle transmitted through the illumination light irradiated on the inspection reticle 4 And an image detection unit 6.

An image processing section 7a for controlling and taking in the image detecting section 6 and performing image signal conversion processing, a pattern data section 8 for storing regularity condition data of a pattern of an inspection reticle in advance, and a rule for the pattern An image processing unit 7b for controlling and taking in sex condition data and performing image signal conversion processing, etc .; and an arithmetic processing unit 9 for comparing and comparing data of the two based on signals from the image processing units 7a and 7b and performing an inspection operation.
a.

Next, the operation of the reticle foreign matter inspection mechanism used in this embodiment will be described. First, the illumination light source 1 irradiates the inspection reticle 4 with illumination light via the filter 2 and the half mirror 3, and scans the entire inspection reticle by a reticle holding mechanism 5 having an XY direction operation function. At this time, it is assumed that the image processing unit 6 is always located on the side opposite to the irradiation surface of the inspection reticle 4 on the optical path of the illumination light, and captures a transmitted image of the inspection reticle 4 through which the illumination light has passed. The transmission image picked up by the image detection unit 6 is subjected to signal processing in an image processing unit 7a, and the pattern regularity condition data of the inspection reticle 4 is compared with data of an image processing unit 7b that performs image signal processing in advance and calculated. The processing unit 9a performs arithmetic processing, and determines that an item that is out of the regularity condition is abnormal, that is, a foreign object, and that all of the items satisfy the regularity condition are normal.

FIG. 2 is a block diagram to which an optical system for explaining a reticle foreign matter inspection mechanism used in a second embodiment of the present invention is added. This embodiment has the same reticle foreign matter inspection function as the first embodiment shown in FIG.
A review function for taking in position information of the foreign matter 12 above is added.

The operation of the review function of this embodiment will be described. The rotation amount of a drive system motor 10 of a reticle holding mechanism 5 having an XY direction operation function for scanning the inspection reticle 4 is detected by a rotation amount detection unit 11, and the detected rotation amount and foreign matter detection by an image processing unit 6 are detected. By synchronizing
The position information of the foreign matter 12 on the inspection reticle 4 is taken in, the arithmetic processing unit 9b performs an arithmetic processing, and the position of the foreign matter on the inspection reticle 4 can be reviewed.

[0013]

As described above, the present invention relates to a reticle cleaning apparatus used in an exposure step of a semiconductor element manufacturing process.
By providing a foreign matter inspection mechanism that detects foreign matter adhering to the reticle surface, it is possible to detect foreign matter that absorbs and transmits laser light that could not be detected by the conventional foreign matter inspection method, and adheres to the reticle. This has the effect of eliminating defects due to transfer during patterning onto the semiconductor element due to foreign matter, thereby improving the yield of the semiconductor element.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a foreign matter inspection mechanism according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a foreign matter inspection mechanism according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a foreign matter inspection mechanism in a conventional reticle cleaning apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination light source 2 Filter 3 Half mirror 4 Inspection reticle 5 Reticle holding mechanism 6 Image detection part 7a, 7b Image processing part 8 Pattern data part 9a, 9b Arithmetic processing part 10 Motor 11 Rotation amount detection part 12 Foreign material 13 Laser mechanism 14 Photoelectric element

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/304 G01N 21/88 H01L 21/027

Claims (1)

(57) [Claims] An illuminating light having a wavelength used in an exposure processing step is irradiated from one surface side of a reticle after reticle cleaning, and transmitted through a reticle pattern from the other surface side. In a reticle cleaning apparatus equipped with a reticle foreign matter inspection mechanism for taking an image, processing the image information, and detecting a portion deviating from the pattern regularity condition data of a previously set image as an abnormality, scanning the reticle in the XY directions. Detects the amount of rotation of the drive motor of the reticle holding mechanism equipped with an operation function,
A reticle cleaning apparatus for synchronizing the detected amount of rotation with the foreign matter detection by the image information processing, taking in positional information of the foreign matter on the reticle, performing arithmetic processing, and reviewing the position of the foreign matter on the reticle; .