JP2795682B2 - Thin film repair processing equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a thin film repairing device, and more particularly, to an irradiation shape of a processing light beam in a device for removing and repairing a residual defect such as a photomask generated by a thin film of chrome or the like. Related to the display.

[Related Art] As a device for correcting a residual defect such as a photomask, a device using laser light such as a yag laser is known.
Since the object to be processed is often composed of a combination of straight lines, the irradiation shape of the laser is controlled by operating a rectangular slit. When processing light in an invisible region such as a yag laser is used, a defect is corrected by manipulating the shape of the rectangular slit using aiming light in the visible region separately.

However, aside from the case where the wavelength of the processing light beam and the wavelength of the aiming light are close, otherwise, the chromatic aberration of both causes
A shift occurs in the imaging position. That is, when a thin film is processed at a slit imaging position of aiming light, the uniformity of the printing process is reduced, and the linearity of the edge is deteriorated. In order to perform uniform and excellent linearity correction processing, the laser slit imaging position must be moved to the thin film surface. However, this has the disadvantage that the focal position in the observation system is shifted, and the thin film surface cannot be observed during processing.

In order to solve this point, Japanese Patent Application Laid-Open No. 52-120377 discloses that the optical path of laser light and aiming light is separated between a rectangular slit and an objective lens to form a square slit image of laser light and a square slit image of aiming light. A technique has been proposed in which a matching optical system is provided for matching the two on the thin film surface.

With the above technology, it was possible to control the slit shape while observing the thin film surface.However, since the output distribution of each laser has characteristics and is not necessarily homogeneous, the slit shape and the actual removal degree are delicate. Is different.

Further, even if the slit shape is controlled while observing the thin film surface, there is a slight individual difference in the judgment of the operator.

In the past, these points had to be managed exclusively depending on the worker's intuition.

[Problem to be Solved] However, there is a big problem depending on such intuition of the worker. Workers need experience to grasp intuition, and training takes a lot of time.

In addition, since work depends on the intuition of the worker, standardization of the work does not progress, and work management is not easy, so that the number of defective corrections increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thin film repair apparatus that improves the reproducibility of an appropriate irradiation shape by quantitatively capturing the size of a slit in view of the above-mentioned conventional technical problems, and facilitates work management. is there.

[Configuration of the Invention] The present invention provides a processing light source,
A slit light forming means for changing a shape of a slit through which a processing light beam emitted from the processing light source is transmitted; an image forming optical system for forming the slit image on a thin film; and a processing light beam for aiming at a corrected portion In a thin film processing apparatus having an aiming means indicating an irradiation area, an imaging optical system for imaging a thin film,
Display means for superimposing and displaying the imaged thin film and the irradiation area by the aiming means; slit shape detecting means for detecting the shape of the slit; and numerical data of the slit based on the detection result of the slit shape detecting means. And numerical data display means for displaying the imaged thin film in the same field of view as the display of the irradiation area by the aiming means.

[Embodiment] A thin film repair apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an arrangement diagram of a basic optical system of a thin film repair apparatus according to one embodiment of the present invention.

A processing light source 1 uses an Nd: YAG laser in this embodiment. Numeral 2 spreads the laser light emitted from the processing light source into a light beam of a required size.

Reference numeral 3 denotes a chromatic aberration shift correction optical system, which includes a lens 4 for correcting chromatic aberration shift and a lens 5 for preventing laser light from condensing in the observation optical system.

In this embodiment, the chromatic aberration shift between the observation light in the visible region and the light beam required for processing in the invisible region is corrected by inserting the lens 4. While the rectangular slit is fixed at a certain position, the same effect as moving the rectangular slit to correct the chromatic aberration shift is optically realized.

In general, since a laser is a parallel light beam, the lens 4
Focus at the focal length of The optical path after the lens 4 is shared with the optical path of the observation system. Therefore, when an optical component of the observation system is present near the focal point of the lens 4, the condensed laser light has a high power density. Therefore, in order to prevent the laser light from condensing after the lens 4, that is, the lens 5 is inserted so as to sandwich the lens 4 and the slit 6 so as not to increase the power density of the laser light incident on the optical components of the observation system. The lens 4 and the lens 5 constitute an afocal system. It is not always necessary that the lenses 4 and 5 are afocal systems, but an afocal system is optimal for efficiently forming an image on a work surface. Here, it is clear that the slit image on the work surface is not affected by the lens 5.

In this type of apparatus, processing with a plurality of objective lenses is required, and since the amount of chromatic aberration shift differs depending on the objective lens, a plurality of types of lenses 4 and 5 are required.

FIG. 2 shows a mechanism capable of exchanging the combination of the lenses 4 and 5 so that the chromatic aberration is corrected with the exchange of a plurality of objective lenses.

17 is a gear, 18 is a knob for rotation, and 19 is a lens holder. When the rotation knob 18 is turned, the lens holder 19 is rotated as a set, and the combination of correction lenses (lens 4 and lens 5) on the optical path is exchanged. The combination of correction lenses set in the lens holder is set according to the number of objective lenses used.

Reference numeral 6 denotes a rectangular slit composed of two slits, whose shape can be freely changed according to the shape of the defect.

The rectangular slit 6 can be switched with a spot stop (not shown). Instead of the spot stop, a method of inserting a condenser lens (not shown) suitable for the objective lens so that the light beam passing through the rectangular slit is focused on the thin film surface may be used. The change in spot size can be controlled by the degree of light collection and light intensity.

Reference numeral 7 denotes an origin sensor for setting the origin position of the slit. For example, a position where the slit is completely tightened is set as the origin, and the origin sensor 7 detects this position as an electric signal. Reference numeral 8 denotes a rotary encoder that divides the moving direction and the moving amount of the slit into unit moving amounts and captures the unit as pulse signals. Based on 7 and 8, the slit width and length are processed and calculated in consideration of the magnification of the objective lens, the correction coefficient of the correction lens 4, and the electronic magnification of the monitor, and are used as aiming marks on the monitor. The details of this point are described in Japanese Patent Application No.
This is described in 233125.

Reference numeral 9 denotes a dichroic mirror that reflects infrared light and transmits visible light, and makes the observation optical system of the television camera 10 and the laser optical system for processing coaxial.

Similarly, these optical systems and the prism 11 make the observation optical system with the naked eye of the observer coaxial.

 Reference numeral 12 denotes a microscope illumination lamp.

Reference numeral 13 denotes an objective lens, and reference numeral 14 denotes a photomask processed sample. Reference numeral 15 denotes a processing operation unit, and reference numeral 16 denotes a display unit on which a monitor is arranged.

FIG. 3 is a block diagram for numerically displaying the size of the irradiation shape of the processing light beam.

Since the size of the rectangular slit 6 can be obtained from information from the origin sensor 7 and the rotary encoder 8, by taking into account the magnification of the objective lens 13 and the correction coefficient of the lens 4 for correction, the size of the rectangular slit image on the work surface is considered. The actual size of the size is obtained. The object to be processed using a rectangular slit is composed of a set of straight lines, and since the length between specific straight lines is known, the actual size of the image on the work surface should be displayed from work management. Is more effective. However, from the viewpoint of reproducibility, it is not always necessary to be restricted to this, and it can be performed as appropriate.

The digital dimensions obtained in this way are converted to video signals and synthesized with the thin-film surface image to create a monitor.
Display above.

In the above embodiment, the aim is obtained by obtaining the shape of the rectangular slit 6 by the origin sensor 7 and the rotary encoder 8 and forming the shape on the monitor. However, another method such as optical detection may be used. In carrying out the present invention, the size of the slit image may be determined by image processing the work surface image of a conventional apparatus described in JP-A-52-120377.

[Effect of the Invention] As described above, according to the present invention, the irradiation shape of the processing light beam can be digitally displayed, so that it can be accurately reproduced and standardization of work management can be achieved. In addition, it is possible to greatly reduce correction errors.

[Brief description of the drawings]

FIG. 1 is a layout view of a basic optical system of a thin film correction apparatus according to one embodiment of the present invention, and FIG. 2 is a combination of lenses 4 and 5 for a plurality of objective lenses so that chromatic aberration is corrected by replacement thereof. FIG. 3 is a block diagram for numerically displaying the size of the irradiation shape of the processing light beam. 1 Laser light source for processing 4 Chromatic aberration correction lens 6 Square slit 13 Objective lens 15 Processing unit 16 Monitor

Continuation of front page (56) References JP-A-61-14640 (JP, A) JP-A-3-13946 (JP, A) JP-A-2-79851 (JP, A) JP-A-55-113015 (JP) JP-A-55-98829 (JP, A) JP-A-58-6128 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 1/08

Claims (1)

(57) [Claims] 1. A processing light source, a slit light forming means for changing a shape of a slit through which a processing light beam emitted from the processing light source passes, and an image forming optical system for forming the slit image on a thin film; In a thin film correction processing apparatus having an aiming means for indicating an irradiation area of a processing light beam in order to aim at a correction portion, an imaging optical system for imaging a thin film, an imaged thin film and an irradiation area by the aiming means are overlapped. Display means for displaying; slit shape detecting means for detecting the shape of the slit; and numerical data of the slit based on the detection result of the slit shape detecting means. And a numerical data display means for displaying in the same field of view.