JPS6052012A - Forming method of partially thin-film - Google Patents

Abstract

PURPOSE:To change each repair into standard operation, and to improve reliability by forming and shaping the broken section of a thin-film pattern to a predetermined shape and forming a thin-film to the broken section. CONSTITUTION:Second laser beams for removing a thin-film of which beams from a laser oscillator 15 are shaped to a predetermined form previously prepared are projected to a broken section 3, the broken section is expanded and shaped to a prescribed form, and a substrate, the broken section thereof is shaped, is exposed to a raw material gas atmosphere. When first laser beams from a laser oscillator 7 for forming the thin film having the same form as the prescribed form are projected to the same position of the broken section, proper quantities of the thin-film keeping flatness to a peripheral section can be formed to the expanded and shaped broken section.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for repairing defects using laser light when forming a thin film with a predetermined pattern on a substrate.

With the recent increase in the density of electronic devices, in order to improve manufacturing yields, a method of efficiently repairing microscopic defects in thin film patterns on photomasks and semiconductor wafers involves irradiating focused laser light onto defective areas. is being put into practical use.

There are two types of defects to be repaired: a black spot defect where a thin film is formed in a place other than a predetermined location, and a white spot defect where a thin film is not formed in a predetermined location. Regarding the repair of sunspot defects, there are methods and apparatuses in which a laser beam is irradiated onto the defective part to evaporate the thin film thereof, and this is particularly well known as a mask repair apparatus for photomasks.

On the other hand, regarding the method and apparatus for repairing white spot defects, in addition to focusing irradiation of a laser beam on a minute defect area, a photochemical reaction is also used to form a thin film with a desired material and thickness using a laser beam. Conventionally, methods and devices have been proposed that utilize the ability to form the same shape as the irradiation pattern.

This conventional method and apparatus will be explained below with reference to FIG. A substrate 1 is placed in a vapor phase growth chamber 4 on a stage 6. The vapor growth chamber 4 is connected to a raw material gas supply system 5. The raw material gas supply system 5 includes a container that generates vapor of an organic compound, a halide compound, a hydrogen compound, etc. that deposits a desired thin film material that can achieve the purpose of repair by thermal decomposition or photolysis, a buffer gas container, and It consists of a pressure regulator that mixes these gases at an appropriate pressure and sends the mixed gas to the vapor growth chamber.

When repairing the defective portion 3 existing in the thin film 2 of a predetermined pattern on the substrate 1, the defective portion 3 is filled with a portion of the raw material gas m.
Focuses laser light at a wavelength that promotes Since the decomposition in this case may be photolysis or thermal decomposition, it goes without saying that a laser beam having a wavelength that is absorbed by the substrate and increases its temperature even if it is not absorbed by the source gas can be used. Laser light is the first
The laser beam is emitted from a laser oscillator 7 and guided to the defective portion 3 through a reflecting mirror 8 and a lens 9. At this time, to align the laser beam on the defective portion 3, the substrate surface is monitored through a reflector 8 by a monitor 10 consisting of a television camera or a CCD camera, and the image signal is transmitted to a controller 11. The controller 11 is a part that automatically controls the entire operation, and drives the two-axis motor of the stage 6 so that the irradiation position of the laser beam based on the video signal matches the position of the defective part 3. Further, after the above positioning is completed, the controller 11 sends an oscillation start signal to the first laser oscillator 7 to cause it to emit laser light. The progress of thin film formation on the defective part 3 is determined by the controller 11 based on the video signal from the monitor 10, and when it is determined that the thin film formation is complete, the controller 11 sends an oscillation end signal to the first laser oscillator 7 again. Then, the repair of the defective part 3 is completed. If there are multiple defects on the same substrate, the same operation may be repeated.

However, the conventional method described above has the following drawbacks. First, since the shape of the defective part 3 is not constant, it is impossible to irradiate the laser beam in accordance with the shape of the defective part 3. For this reason, irradiation of the peripheral thin film 2 with laser light becomes inevitable, and in this case, the formation of the thin film also progresses in the peripheral area, and a flat finish cannot be obtained after the repair is completed. Moreover, if the thin film formation rate is higher in the peripheral area, the defective area 3
In some cases, the film thickness at the peripheral portion exceeds the allowable value before the repair of the defective portion 3 is completed, and in fact, the defective portion 3 cannot be repaired using the conventional method. Furthermore, if the spot size of the laser beam is changed for each repair in accordance with the size of the defective portion 3, the thin film formation rate per unit illuminance changes, making it impossible to obtain highly reliable repair. On the other hand, by concentrating the laser beam to a spot diameter sufficiently smaller than the average size of the defect 3 and repeating the repair by scanning the laser beam inside the defect 3, the above drawbacks of the conventional method can be overcome to some extent. Although there are ways to avoid this problem, it would conversely lengthen the repair time and create new drawbacks in improving the required positioning accuracy.

The purpose of the present invention is to eliminate the drawbacks of the conventional methods described above, improve reliability by standardizing each repair, and provide a new local thin film formation method that is easy to use and is excellent in flattening the thin film after repair. K provides a method.

The method of the present invention includes the steps of shaping a defective portion of a thin film pattern formed on the top of a substrate into a predetermined shape, exposing the substrate with the defective portion shaped to a source gas atmosphere, and applying the shaped defective portion to a predetermined shape. The method is comprised of a step of irradiating a laser beam having the same cross-sectional shape as the predetermined shape of the light beam to form a thin film in the defective portion.

The feature of the present invention is that the defect is enlarged and shaped into a predetermined shape by irradiating the defect with a second laser beam for thin film removal, the beam of which is shaped into a predetermined shape prepared in advance. The first laser beam for forming a thin film with the same shape as the shape is irradiated on the same location of the defect to form a thin film that is enlarged and shaped, and maintains the same shape as the surrounding area, with no excess or deficiency in the defect. It is possible to do so.

Embodiments of the present invention will be described in more detail below with reference to the drawings. FIG. 2 is a configuration diagram showing an embodiment of the present invention. Like-numbered components are the same as in FIG. The new additions are aperture 12° and aperture condensing lens 13. Second reflecting mirror 14 and second laser oscillator 1
It is 5. However, the controller 110 functionality needs to be expanded, as will be made clear below.

The second laser beam emitted from the second laser oscillator 15 passes through the reflecting mirror 140 and the reflecting mirror 8, and is focused near its focal point by the aperture focusing lens 13. An aperture 12 that shapes the beam of the second laser light into a predetermined shape is arranged at the location where the light is focused. The image of this aperture 12 is focused on the defective part 3 by the lens 9. The intensity of this second laser beam is determined by the intensity of the imaged aperture 1
The pulse width of the second laser beam is set to be large enough to evaporate the thin film on the substrate in the shape of No. 2, and the pulse width of the second laser beam is set to be short enough to minimize the thermal effect on the surroundings of this shape. a second laser oscillator 15 suitable for this purpose.
For this purpose, a Q-switched YAG laser or its high frequency, or a high-output solid-state laser such as a Q-switched alexandrite laser is suitable. Of course, a high-output, short-pulse oscillation gas laser such as an N laser or an excimer laser can also be used.

The standard shape of the aperture 12 is rectangular. For a defective portion 3 larger than a standard rectangle, it is sufficient to cover the defective portion 3 with a set of a plurality of rectangles adjacent to each other by one dimension, and remove all the thin film contained therein. Of course, depending on the purpose, a plurality of apertures 12 may be prepared and a turret method or other aperture replacement method may be adopted.

For actual removal, the monitor 10 and the stage 6 are linked via the controller 11 for positioning, and then the controller 11
The process is completed by a series of operations in which the second laser beam is emitted from the second laser oscillator 15 in response to the trigger signal from the second laser oscillator 15. This operation itself is basically the same as what is widely performed in mask repair.

The present invention further includes a first laser oscillator 7 for forming a thin film.
The first laser beam emitted from the second laser beam is overlapped coaxially with the second laser beam, and the first laser beam also passes through the aperture 12 so that the shape of the beam is exactly on the enlarged and shaped defect 3 on the substrate 1. Irradiate to match. Therefore, a thin film is formed again in the portion that was removed by the second laser beam.

In this way, a flat thin film without any ridges is regenerated around the puyu, and the repair is completed.

As described above, the controller 11 of the present invention has, in addition to the conventional functions shown in FIG. The advantage of using a non-point board to judge the image signal from the monitor 10 is that the shape of thin film formation is standardized, which greatly reduces the variation in thin film formation speed, which was a drawback of the conventional method, and improves the reproducibility of thin film formation. It is possible to repair white spot defects and black spot defects simultaneously on the spot, and the repair time can be significantly shortened. In addition, in the white spot defect repair according to the present invention, a process of irradiating a second laser beam is added to the conventional method, but the time required for this is extremely short, and there is no impact on the overall repair time. There are very few cattails. On the contrary, since the reliability of repair according to the present invention is improved, the need for re-repair is greatly reduced, so that the repair time can be significantly shortened.

It should be noted that FIG. 2 shows one embodiment according to the present invention, and it goes without saying that possible modifications may be made without departing from the spirit of the present invention.

For example, the reflector 8 was used to overlap the first laser beam and the second laser beam, but it is possible to make the polarizations of both laser beams orthogonal and use a polarizing plate instead of the reflector. Of course it is possible. It is also possible, of course, to make the design of the reflecting mirror 8 easier by making the wavelengths of both laser beams different.

A two-beam system may be used without overlapping the optical axes of the two laser beams. Furthermore, it is also possible to use the same laser oscillator as both the first laser oscillator 7 and the second laser oscillator 15, and to perform the functions of both laser oscillators by changing only its operating mode. Specifically, for example, a combination of a Q-switched YAG laser and a harmonic generator is used as a laser oscillator, and the second laser beam for thin film removal is a fundamental wave, second harmonic, or fourth harmonic of the YAG laser. It is sufficient to use light in an appropriate wavelength range of waves and with high energy per unit. On the other hand, the first laser beam for forming a thin film is ultraviolet light of the third harmonic or fourth harmonic of a YAG laser, which has a lower output than the second laser, and may be used to form a thin film. It is best to use a laser beam with an intensity that does not remove the particles. Therefore, the difference in the operation mode mentioned above is that harmonic ultraviolet light having the same wavelength may differ only in output level, and the first laser oscillator 7 may include up to the fourth harmonic generator. As the second laser oscillator 15, we used two 0-source sources, which may have different wavelengths, such as a second harmonic generator or an oscillator that generates only the fundamental wave without harmonic generation, but only one light source was used. It is also possible to provide the function of shaping the defect and forming a thin film.

Furthermore, in the embodiments of the present invention, the laser beam was not moved and the substrate was placed on a stage and moved, but it goes without saying that the substrate may be fixed and the laser beam scanned. They may be used together depending on the purpose.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of a local thin film forming apparatus according to a conventional method, and FIG. 2 is a conceptual diagram of a local thin film forming apparatus for embodying the present invention. 2... thin film, 3... defective part, 4...
Vapor phase growth chamber, 5... Source gas supply system, 6... Stage, 7... First laser oscillator, 8... Reflector, 9...
...Lens, 10...Monitor, 11...Controller, 12...Aperture, 13...Condensing lens for aperture, 14...Second reflecting mirror, 15...
represents a second laser oscillator.

Claims (1)

[Claims] A process of shaping the defective part of the thin film pattern formed on the substrate into a predetermined shape, exposing the substrate with the defective part shaped to a source gas atmosphere, and applying the predetermined shape and the original beam to the shaped defective part. 1. A method for forming a local thin film, comprising the step of irradiating a laser beam with the same cross-sectional shape to form a thin film on the defective part.