JPH0545051B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a semiconductor exposure apparatus, and particularly to a semiconductor exposure apparatus used for exposing fine patterns using an ultraviolet laser or the like.

(Prior Art) A conventional semiconductor exposure apparatus uses an optical system as shown in FIG. That is, the laser beam emitted from the laser oscillator 31 is divided into parts by the integrator 32, the intensity distribution of the light is smoothed, and the pattern on the mask 33 is imaged onto the object 35 by the imaging optical element group 34. It is configured. FIG. 6 shows the structure of the integrator 32. The integrator 32 is made by bundling a plurality of glass rods or optical fibers, and each rod or optical fiber functions as a lens.

Laser light emitted from the laser oscillator 31 is magnified by magnifying lenses 36 and 37 and enters the input end 38 of the integrator 32. The laser beam exiting the integrator 32 passes through a mask 33 having a predetermined pattern and imaging lenses 39, 40, and 41, and enters the wafer 35, where the pattern drawn on the mask 33 is imaged onto the object to be imaged. do.

In recent years, semiconductor devices have become more highly integrated, and there is a corresponding demand for miniaturization of exposure. Accordingly, it has become necessary to shorten the wavelength of the laser light used, and experiments are being conducted to develop ultraviolet lasers as a light source for this purpose.

(Problems to be Solved by the Invention) As described above, in the conventional technology, ultraviolet lasers with short wavelengths have come to be used for the recent high integration of semiconductor devices. However, the laser light from an ultraviolet laser has high coherence, resulting in an irregular pattern called a speckle pattern.
The drawback was that noise was printed onto the exposed pattern.

The present invention provides a semiconductor exposure apparatus that can remove such speckle patterns and expose only the original pattern.

[Structure of the Invention] (Means for Solving the Problems) The present invention has been made in consideration of the above-mentioned problems, and uses a laser magnifying optical system to expand the laser light emitted by the laser oscillator to increase the light intensity. A semiconductor exposure apparatus that performs exposure by uniformizing the distribution of light and projecting it onto a mask, and forming a transmitted light image of the mask onto an object using an imaging optical system, includes a bundle of transparent thin wire members, and a bundle of thin transparent wire members; The semiconductor exposure apparatus is characterized in that an optical means for removing a speckle pattern is provided on the optical path of the laser beam, and includes a drive mechanism that is connected to a side surface of the bundle and vibrates the bundle.

Further, the present invention expands the laser light emitted by the laser oscillator using a laser enlarging optical system, makes the light intensity distribution uniform, and projects it onto a mask, and the transmitted light image of the mask is formed on a target object using an imaging optical system. A semiconductor exposure apparatus that performs exposure by forming an image upward, comprising: a transparent phase plate having a dense uneven pattern on a bottom surface; and a drive mechanism connected to the phase plate to rotate or vibrate the phase plate. The semiconductor exposure apparatus is characterized in that an optical means for removing a speckle pattern is disposed on the optical path of the laser beam.

(Function) As described above, an optical element is provided in the integrator section to make the intensity distribution of the light uniform by dividing the laser light into smaller pieces, and to change the phase distribution of the laser light irradiated onto the mask over time. In this way, the speckle pattern imaged on the wafer can be made uniform over time and can be removed.

(Example) A first example of a semiconductor exposure apparatus having the present invention is described below.
This will be explained using FIG.

FIG. 1 shows the configuration of an embodiment of the present invention. This semiconductor exposure apparatus includes a laser oscillator 1, a laser expansion optical system 2 that expands the laser beam emitted from the laser oscillator 1 and makes the intensity distribution of the light uniform, and the laser expansion optical system 2 and a member to be printed. wafer 4
It has an imaging optical system 5 which includes an exposure mask 3 and three imaging lenses arranged on the same optical axis.

The laser enlarging optical system 2 includes an optical fiber bundle 8 whose entrance end 6 and exit end 7 are fixed at both ends and whose center part can vibrate, and a drive shaft 9 attached near the center of the optical fiber bundle 8. , the drive unit 1 connected to this
0, and a pair of lenses 11 and 12 disposed on the output side of the laser oscillator 1 to magnify the laser light output from the laser oscillator 1 and guide it to the input end 6 of the optical fiber bundle 8. When the machine 10 starts, the vicinity of the center of the optical fiber bundle 8 vibrates.

The optical system 5 also includes an exit end 7 of the optical fiber bundle 8.
A collimating lens 13, the exposure mask 3, and an imaging lens 1 are sequentially arranged on the same optical axis from the side.
Consisting of 4, 15, and 16.

The operation of the semiconductor exposure apparatus as described above is such that ultraviolet laser light such as excimer laser output from the laser oscillator 1 is magnified by the lens 11 and guided to the optical fiber bundle 8 of the integrator section 2 by the lens 12. . The laser light that enters each optical fiber is reflected on the inner surface of the optical fiber and then exits from the exit end 7. The emitted laser beam is collimated by the collimating lens 13, irradiated onto the exposure mask 3, passes through the IC pattern of the exposure mask 3, enters the imaging lenses 14, 15, and 16, and is applied onto the wafer 4. The IC pattern of the exposure mask 3 is imaged on the exposed photosensitive layer and exposed.

At this time, when the driver 10 vibrates the optical fiber bundle 8 via the drive shaft 9, the way the laser light is reflected within the optical fiber changes, and the phase of the laser light emitted from the optical fiber bundle 8 changes over time. It's going to change. As a result, the speckle pattern appearing on the wafer 4 changes its shape as the phase of the laser beam changes, so when the wafer 4 is exposed to the laser beam for a certain period of time, the speckle pattern is averaged and only the IC pattern is placed on the wafer 4. Can be exposed to light.

The amount of vibration at this time is equal to the minimum pattern size of the speckle pattern appearing in the imaged pattern.

Next, a second embodiment shown in FIG. 2 will be described. The optical fiber bundle 8 of the integrator section 2 of the first embodiment is replaced by a glass rod bundle 17, and a drive machine 10 to which the glass rod bundle 17 is connected via a drive shaft 9 so as to vibrate. This drive machine 1
By vibrating the laser beam by a predetermined amount, the way the laser beam is reflected within the glass rod bundle 17 changes, and the phase of the laser beam emitted from the glass rod bundle 17 changes with time. As a result, the speckle pattern appearing on the wafer 4 changes its shape as the phase of the laser beam changes, so when the wafer 4 is exposed to the laser beam for a certain period of time, the speckle pattern is averaged, and only the IC pattern is left on the wafer 4. Can be exposed to light.

Next, the configuration of the third embodiment shown in FIG. 3 will be shown. In the laser enlarging optical system 2 of the first and second embodiments, instead of vibrating the optical fiber bundle 8 and the glass rod bundle 17 with the driver 10, a third
As shown in the figure, a phase plate 19 and a driver 20 for rotating the phase plate 19 are provided in front of the input end 18 of the optical fiber bundle 8 or the glass rod bundle 17. Phase plate 1 here
Reference numeral 9 denotes a transparent plate having a fine concavo-convex pattern on its surface, and when a laser beam is incident thereon, the phase of the laser beam changes according to the concavities and convexities. By rotating this plate, the phase of the laser beam changes over time, and the speckle pattern is averaged.

Further, in the present invention, the phase plate may be placed immediately before the mask as shown in FIG.

Furthermore, although the integrator was vibrated in the first and second embodiments, it may be rotated like the phase plate in the third embodiment, or vice versa. You may let them. Further, the same effect can be obtained even if such a phase plate is provided after the optical fiber. Furthermore, the effects of the invention will not be affected even if a reflective plate is used instead of a transparent plate for the phase plate.

[Effects of the Invention] As described above, when exposing a pattern, by providing an optical element that temporally changes the phase of the optical laser in the laser expansion optical system that smoothes the intensity distribution of the laser beam, it is possible to reduce the speckle. By averaging the patterns, it is possible to accurately image only the exposure mask pattern onto the member to be exposed, even if the pattern is particularly fine.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of a semiconductor exposure apparatus using the present invention, FIG. 2 is a diagram showing the configuration of the second embodiment, and FIG. 3 is the configuration of the third embodiment. FIG. 4 is a diagram showing the configuration of a modification of the third embodiment, FIG. 5 is a diagram showing the configuration of a conventional semiconductor exposure apparatus, and FIG. 6 is a diagram showing the configuration of an integrator. be. 1... Laser oscillator, 2... Laser enlarging optical system, 3... Exposure mask, 4... Wafer, 8...
Optical fiber bundle, 13...Collimating lens, 17
...Glass rod bundle, 10,20...Driver, 1
9... Phase plate.

Claims (1)

[Claims] 1. Laser light emitted by a laser oscillator is expanded by a laser enlarging optical system to make the light intensity distribution uniform and projected onto a mask, and a transmitted light image of the mask is focused by an imaging optical system. In a semiconductor exposure apparatus that performs exposure by forming an image on an object, an optical system for removing speckle patterns includes a bundle of transparent thin wire members and a drive mechanism connected to a side surface of the bundle to vibrate the bundle. A semiconductor exposure apparatus characterized in that a means is disposed on the optical path of the laser beam. 2. The laser beam emitted by the laser oscillator is expanded by a laser expansion optical system to make the light intensity distribution uniform and projected onto a mask, and the transmitted light image of the mask is formed on the target object by an imaging optical system. A speckle pattern comprising: a transparent phase plate having a dense uneven pattern on its lower surface; and a drive mechanism connected to the phase plate to rotate or vibrate the phase plate. A semiconductor exposure apparatus characterized in that a deletion optical means is disposed on the optical path of the laser beam.