JPH07226367A - Light exposure equipment and manufacture of device by using this equipment - Google Patents

Abstract

PURPOSE:To provide a light exposure device which is capable of lessening laser rays in wavelength band width without deteriorating them in oscillation intensity. CONSTITUTION:A light exposure device is equipped with prisms 3a and 3b which split nearly parallel laser rags emitted from a laser 1 by the wavelength, a convex lens 4 which condenses laser rays transmitted through the prisms 3a and 3b by wavelength, and a slit 5 which enables only laser rays of required wavelength band out of laser rays condensed by the convex lens 4 to pass through it are provided. A convex lens 6 which collimates laser rays that pass through the slit 5 by wavelength, prisms 7a and 7b which have the same angle of dispersion with the prisms 3a and 3b but have the direction of dispersion opposite to that of the prisms 3a and 3b and compose laser rays collimated by the lens 6 by wavelength, an optical system 8 which irradiates a mask 9 with nearly parallel laser rays transmitted through the prisms 7a and 7b, and an optical system 10 which projects a device pattern printed on the mask 9 onto a wafer 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and a device manufacturing method, and particularly to an IC, an LSI, a CCD, a liquid crystal panel,
The present invention relates to an exposure apparatus used for manufacturing various devices such as a magnetic head and a device manufacturing method.

[0002]

2. Description of the Related Art In recent years, with the high integration of semiconductor devices, there has been a demand for an exposure apparatus having a high resolution and a large exposure area. As an apparatus that responds to this requirement, scanning is performed while scanning a mask and a wafer. A mold reduction projection exposure apparatus is drawing attention.

On the other hand, in order to realize a finer resolution line width, it is desired to use light having a shorter wavelength as exposure light. Therefore, it is considered to use an excimer laser or the like that emits strong light in the far ultraviolet region in the scanning type reduction projection exposure apparatus.

[0004]

However, the oscillation spectrum of the excimer laser has a full width at half maximum (FWHM) of about 0.3 n in the case of, for example, a KrF excimer laser.
Therefore, it cannot be said that the wavelength width is sufficiently narrow.

In this case, it is sufficient to equip the laser resonator with a band narrowing unit for narrowing the wavelength width of the laser light, but there is a drawback that the stability of the oscillation intensity of the laser light is impaired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure apparatus capable of narrowing the wavelength width of laser light while stabilizing the oscillation intensity of laser light.

In order to achieve this object, the exposure apparatus of the present invention has a first dispersion element for dispersing substantially parallel laser light from a laser for each wavelength, and a laser light from the first dispersion element having a wavelength. A first convex lens that collects light for each wavelength; a wavelength selection unit that allows a laser light in a desired wavelength range of the laser light condensed by the first convex lens for each wavelength to pass; and the wavelength selection unit. Angular dispersion is almost the same as that of the second convex lens for making the passed laser light parallel light for each wavelength and the first dispersion element for combining the laser light made parallel light for each wavelength by the second convex lens. It is characterized by having a second dispersive element having the same dispersion direction but opposite direction. Since the dispersive element is provided outside the resonator of the laser to narrow the wavelength width of the laser light, the oscillation of the laser light is generated. Stable strength To have.

A second convex lens for collimating the laser light passing through the wavelength selecting means into parallel light for each wavelength, and the second convex lens
The first dispersive element for synthesizing the laser light made into parallel light for each wavelength by the convex lens and the second dispersive element having substantially the same angular dispersion but opposite directions of dispersion, The occurrence of deviation of the wavelength distribution in the cross section of light is reduced or eliminated.

Further, by constructing the wavelength selecting means so that the size of the laser light pass band can be changed, it becomes possible to supply laser light having an arbitrary wavelength width suitable for various wafer processes. For example, it is preferable to configure a slit means having a variable slit width as the wavelength selection means.

The first and second dispersive elements can be constituted by prisms, diffraction gratings and the like. The laser may be an excimer laser.

According to the present invention, the mask and the substrate are scanned with the laser light from the second dispersion element, and the pattern of the mask is projected onto the substrate, which has a high resolving power. A mold exposure apparatus can be provided.

According to the present invention, it is also possible to provide a device manufacturing method capable of manufacturing a device having a large area and a high degree of integration.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention in which IC, LS
1 shows a scanning-type reduction projection exposure apparatus used for manufacturing various devices such as I, CCD, liquid crystal panel, and magnetic head.

In FIG. 1, 1 is a laser which is a light source,
Reference numeral 2 denotes laser light emitted from the laser 1, which is substantially parallel light. Reference numerals 3a and 3b are prisms that are laser light dispersion elements for each wavelength, 4 is a first convex lens that collects the laser light dispersed by the prisms 3a and 3b for each wavelength, and 5 is a first convex lens 4. A variable slit having a variable width of a region (aperture), which is arranged at the focal position of the optical disc, through which light passes, 6
Is a second convex lens arranged at a focal distance from the variable slit 5, 7a and 7b are prisms having the same angular dispersion as the prisms 3a and 3b, 8 is an illumination optical system, and 9 is a device to be transferred onto a wafer. A mask on which a pattern is formed, 10 is a projection optical system that projects the device pattern of the mask onto a wafer, 11 is a wafer onto which the device pattern of the mask 9 is transferred, and 12 is a variable slit 5 that drives the variable slit 5 to adjust the width of the opening. It is a slit width adjuster that changes.
The mask 9 and the wafer 11 are made to scan the laser beam and the optical system 10 in the direction of the arrow.

In the exposure apparatus of this embodiment, the width of the opening of the variable slit 5 is adjusted so as to supply only the laser light having the wavelength width of 0.1 nm to the illumination optical system 8, and the dispersion element is provided outside the resonator of the laser 1. Since the laser light 2 is provided and the wavelength width of the laser light 2 is narrowed, the oscillation intensity of the laser light 2 is stable. There is.

When the laser 1 is a KrF excimer laser, the laser 1 oscillates a laser beam 2 having a wavelength width of 0.3 nm. The laser light 2 is dispersed by the prisms 3a and 3b.
Are dispersed by the convex lens 4 and are condensed on the variable slit 5 for each wavelength by the convex lens 4.

The angular dispersion on each surface of the prisms 3a and 3b is given by the following equation.

D θ / dλ = (d θ / dn) (d n / dλ) where λ is the wavelength of the laser beam-2, θ is the incident angle, and n is the refractive index of the prisms 3a and 3b with respect to the light of wavelength λ. Is.

The prism glass material is synthetic quartz, the excimer laser 1 is a KrF laser, and the apex angles of the prisms 3a and 3b are 82.
If it is used at a minimum declination angle of λ, λ = 248nm n = 1.5084 d n / dλ = -5.6 × 10-4 / nm d θ / dn = (1 / n) tan θ = 4.56rad, so d θ / dλ =- It will be 2.55 mrad / nm.

When two prisms are used for dispersion as in the present embodiment, there are four refracting surfaces, so if the focal length of the convex lens 4 is f and the width L of the opening of the slit 5 is, the slit 5 is The wavelength width Δλ that passes is Δλ = L · (f · 4dθ / dλ). Therefore, in order to obtain the light having the wavelength width Δλ, the width L of the opening of the slit 5 is set to L = f · 4d θ / dλ · Δλ −−−− (1).

For example, when f = 100 mm, the slit 5
In order to make the wavelength width of the laser light after passing 0.1 nm, the slit width L is L = 0.10 mm.

The wavelength width of the laser light after passing through the slit 5 is
When it is desired to set the width to about 0.3 nm, the slit width adjuster 12 may be used to set the width L of the opening of the slit 5 to 0.30 mm or more.

The intensity of the laser beam 2 guided to the illumination optical system 8 changes by changing the width of the opening of the slit 5. Therefore, if resolution is required, the slit width may be narrowed to have a wavelength width of about 0.1 nm. If throughput is important and it is desired to guide as strong light as possible to the illumination optical system 8, the slit is opened. You can adjust it like this.

The laser light 2 which has passed through the slit 5 has a wavelength deviation depending on the traveling direction, but like the exposure apparatus of this embodiment, the convex lens 4, the prisms 3a and 3b are used.
When the laser light is returned to parallel light by the convex lens 6 and the prisms 7a and 7b having the same shape as that of the slit 5 and symmetrically arranged with respect to the slit 5, and dispersion opposite to that generated by the prisms 3a and 3b is given, It is possible to eliminate the bias and guide it to the illumination optical system 8.

The laser beam 2 is shaped by the illumination optical system 8 so as to have a predetermined NA and illuminance distribution, and then is irradiated on the mask 9. After passing through the mask 9, the device pattern of the mask 9 is projected on the wafer 11 in a reduced scale. The wafer 11 is exposed to light through the projection optical system 10 provided in the.

When changing the wavelength width Δλ of the exposure light, the slit width adjuster 12 may adjust the slit width L of the variable slit 5 according to the equation (1).

FIG. 2 shows a second embodiment of the present invention, which is IC, L
1 shows a scanning-type reduction projection exposure apparatus used to manufacture various devices such as SI, CCD, liquid crystal panel, and magnetic head. 2, the same members as those in FIG. 1 are designated by the same reference numerals as those in FIG.

The exposure apparatus of FIG. 2 differs from the exposure apparatus of FIG. 1 in that a member 13 is provided. The member 13 is used when the divergence angle of the laser light 2 is too large to be ignored when the laser light is dispersed by the prism in order to obtain the light with the desired wavelength width Δλ.

The member 13 is a beam expander which expands the laser light 2 emitted from the laser 1 and reduces the divergence angle.
Thus, the exposure light having the wavelength width Δλ can be accurately obtained by changing the expansion rate of the diameter of the laser light according to the divergence angle Δθ of the prism and the divergence angle of the laser light 2.

FIG. 3 shows a third embodiment of the present invention, which is IC, L
1 shows a scanning-type reduction projection exposure apparatus used to manufacture various devices such as SI, CCD, liquid crystal panel, and magnetic head. 2, the same members as those in FIG. 1 are designated by the same reference numerals as those in FIG.

The exposure apparatus of FIG. 3 is different from the exposure apparatus of FIG. 1 in that a grating (diffraction grating) is used as a dispersing element instead of a prism. In FIG. 3, 1
Reference numerals 3 and 14 are gratings which are dispersive elements, and 13
1 is provided in place of the prisms 3a and 3b in FIG. 1, and 14 is provided in place of the prisms 7a and 7b in FIG. Generally, a grating has a larger angular dispersion than a prism.
Exposure apparatus is advantageous.

An embodiment of a device manufacturing method using the exposure apparatus shown in FIGS. 1 to 3 will be described.

FIG. 4 shows a manufacturing flow of semiconductor devices (semiconductor chips such as IC and LSI, liquid crystal panels and CCDs). In step 1 (circuit design), the circuit of the semiconductor device is designed. In step 2 (mask manufacturing), a mask (reticle 304) on which the designed circuit pattern is formed is manufactured. On the other hand, in step 3 (wafer manufacturing), a wafer (wafer 306) is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by the lithography technique using the mask and the wafer prepared above. The next step 5 (assembly) is called a post-process, which is a process of making chips using the wafer prepared in step 4, and an assembly process (dicing, bonding
_B ring), a packaging process (chip encapsulation). In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step 7).

FIG. 5 shows a detailed flow of the wafer process. In step 11 (oxidation), the surface of the wafer (wafer 306) is oxidized. Step 12 (CV
In D), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted in the wafer. Step 15 (resist processing)
Then, a resist (photosensitive material) is applied to the wafer. In step 16 (exposure), the projection exposure apparatus exposes the wafer with an image of the circuit pattern of the mask (reticle 304). In step 17 (development), the exposed wafer is developed. In step 18 (etching), parts other than the developed resist are scraped off. In step 19 (resist stripping), the resist that is no longer needed after etching is removed. By repeating these steps, a circuit pattern is formed on the wafer.

By using the manufacturing method of this embodiment, it becomes possible to manufacture a highly integrated device, which was difficult in the past.

[0035]

As described above, according to the present invention, the first dispersion element for dispersing the substantially parallel laser light from the laser for each wavelength and the laser light from the first dispersion element for each wavelength are condensed. A first convex lens, a wavelength selecting means for passing a laser light in a desired wavelength range among the laser lights condensed by the first convex lens for each wavelength, and a laser light passing through the wavelength selecting means. A second convex lens that makes the light parallel for each wavelength, and the first convex lens for synthesizing the laser light that is made parallel light for each wavelength by the second convex lens.
By having the second dispersion element whose angular dispersion is almost the same and the direction of dispersion is opposite, the wavelength width of the laser light can be narrowed while the oscillation intensity of the laser light is stabilized. It is possible.

A second convex lens for collimating the laser light passing through the wavelength selecting means into parallel light for each wavelength, and the second convex lens
The first dispersive element for synthesizing the laser light made into parallel light for each wavelength by the convex lens and the second dispersive element having substantially the same angular dispersion but opposite directions of dispersion, There is a special effect that it is possible to reduce or eliminate the occurrence of the deviation of the wavelength distribution in the light cross section.

Further, by constructing the wavelength selecting means so that the size of the pass band of the laser light (width of the opening of the slit, etc.) can be changed, laser light of an arbitrary wavelength width suitable for various wafer processes can be obtained. Can be supplied.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the present invention.

FIG. 4 is a diagram showing a device manufacturing flow.

FIG. 5 is a diagram showing a wafer process.

[Explanation of symbols]

 1 Laser 2 Laser Light 3a, 3b, 7a, 7b Prism 4, 6 Convex Lens 5 Variable Slit 8 Illumination Optical System 9 Mask, 10 Projection Optical System, 11 Wafer 12 Slit Width Adjuster 13 Beam Expander 14, 15 Grating

Claims (7)

[Claims] 1. A first dispersion element that disperses substantially parallel laser light from a laser for each wavelength, a first convex lens that condenses the laser light from the first dispersion element for each wavelength, and Wavelength selecting means for passing the laser light of a desired wavelength region among the laser light condensed by the first convex lens for each wavelength, and the laser light passing through the wavelength selecting means is made into parallel light for each wavelength. The second convex lens and the first dispersive element for synthesizing the laser light made into parallel light for each wavelength by the second convex lens have almost the same angular dispersion but opposite directions of dispersion. An exposure apparatus having a dispersion element. 2. The exposure apparatus according to claim 1, wherein the wavelength selection unit includes a slit. 3. The exposure apparatus according to claim 1, wherein the wavelength selection means can change the size of the pass band of the laser light. 4. The exposure apparatus according to claim 1, wherein the first and second dispersive elements include prisms. 5. The exposure apparatus according to claim 1, wherein the first and second dispersive elements each include a diffraction grating. 6. The exposure apparatus according to claim 1, wherein the mask and the substrate are scanned with the laser light from the second dispersion element, and the pattern of the mask is projected onto the substrate. 7. A device manufacturing method, characterized in that a device is manufactured using the exposure apparatus according to any one of claims 1 to 6.