JPH01291425A - Aligner - Google Patents

Abstract

PURPOSE:To eliminate an irregular exposure even if a starting point is moved by superposing luminous fluxes radiated from gathered optical fibers by a plurality of gathered optical fibers, a sole summarizing optical fiber, and a condenser lens, introducing the fluxes into the summarizing fiber, and radiating them. CONSTITUTION:When a starting point 10a is moved to reduce an incident light amount to an optical fiber 22-1 corresponding to an optical fiber 14-1, only a light amount radiated from optical fibers 22-1 is reduced lower than a light amount radiated from other optical fibers 22-1 to 22-4. Luminous fluxes radiated from the optical fibers 22-2 to 22-4 are superposed to be introduced into an optical fiber 23, light rays from the fibers 22-1 to 22-4 are gathered at a step of radiating from the fiber 23 to be regularly integrated. Thus, even if the distribution of illuminance on reticles 2 is slightly reduced at its level as shown by a line Va, it is entirely maintained substantially constant. Accordingly, even if the distribution of the illuminance of an image 5 is slightly reduced at its level, it is wholly maintained substantially constant, a contracted device pattern is uniformly exposed on a wafer 4, and no irregular exposure occurs.

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to prevent uneven exposure from occurring even when the starting point of the light source moves in an exposure apparatus used for manufacturing semiconductor devices. The device includes wavelength selection means disposed around the light source for selecting light of a specific wavelength necessary for exposure from among the light from the light source, and means for condensing the light of the wavelength selected by the wavelength selection means. In the exposure vt position where exposure is performed using the light focused by the light focusing means, the light focusing means is arranged so that the light flux from the wavelength selection means is incident thereon, and the light flux that is incident thereon is collected. A plurality of arranged optical fibers for gathering, a single optical fiber for receiving the light beams emitted from the optical fibers for gathering and emitting them together, and each of the optical fibers for gathering and a condenser lens provided for each of the converging optical fibers and arranged to condense the light beam emitted from the collecting optical fiber onto the incident surface of the emitting optical fiber,
The light beams emitted from each grouping optical fiber are arranged so that they overlap, enter the grouping optical fiber, and are emitted from the grouping optical fiber.

[Industrial application field]

The present invention relates to an exposure apparatus used for manufacturing semiconductor devices.

2. Description of the Related Art A reduction projection type exposure apparatus, for example, is used in an exposure process for printing a device pattern onto a wafer, which is one of the manufacturing processes of semiconductor devices.

As the integration density of ICs increases, the patterns exposed to light have also become finer. As this pattern becomes finer,
The uniformity of pattern formation on the wafer surface is likely to be impaired, the quality of the final product semiconductor Iff is degraded, and the yield is lowered.

Therefore, with the miniaturization of patterns, there is an increasing demand for uniformity of illuminance over the entire surface of the pattern.

[Conventional technology]

FIG. 6 shows a schematic configuration of an example of a conventional exposure apparatus 1. As shown in FIG. This exposure bag ff1 is of a reduction projection type.

2 is a reticle, on which a device pattern 3 is formed. 4 is a wafer. Device pattern 3 J&5 is projected onto wafer 4 and exposed.

10 is a mercury lamp light source, -11 is a wavelength selection means, and 12 is a condensing means.

The wavelength selection means 11 includes four dichroic mirrors 13-1 to 13-4 arranged around the light source 10.

The integrating means 12 mainly consists of optical fibers 14-1 to 14-4 arranged in an inverted V shape and whose lower ends are bundled together.

15 is a bundling part.

The light emitted from the light source 10 to the surroundings is condensed by the first condenser lenses 16-1 to 16-2, and reaches the dichroic mirrors 13-1 to 13-4, as shown by broken lines. Mirrors 13-1 to 13-4 serve as filters,
Absorbs light with wavelengths other than specific wavelengths and is necessary for exposure.
Light with a wavelength of 9 nm is selected and reflected.

Each reflected light is transmitted through second condenser lenses 17-1 to 17-
The light is focused and incident on each optical fiber 4-1 to 14-4.

The light passes through each of the optical fibers 4-1 to 14-4, is collected, and is emitted from the exit surface 15a of the bundling portion 15.

The light diffused and emitted from the exit surface 15a is condensed by the third condenser lens 18, and is then focused by the reduction projection lens 1.
9 onto the wafer 4, the device pattern 3 is imaged on the upper surface of the wafer 4, and the wafer 4 is exposed.

The exit surface 15a of the bundling part 15 is configured such that the other ends of the optical fibers 14-1 to 14-4 are in close contact with each other, as shown in an enlarged view in FIG.

When the starting point 10a of the light source 10 is at a predetermined position, the light m incident on each of the optical fibers 14-1 to 14-4 is equal, and the luminance distribution on the exit surface 15a of the bundle part 15 is as follows.
As shown by line I in the figure, it is approximately constant over the entire exit surface.

In this way, when the brightness is uniform over the entire surface of the exit surface 15a, the distribution of illuminance on the reticle 2 is approximately constant over the entire surface, as shown by the line ■ in FIG. .

Therefore, the distribution of illuminance of the image 5 is approximately constant over the entire image, as shown by the line ■ in FIG. As a result, wafer 4
In this step, the device pattern 3 is exposed uniformly over the entire surface.

[Problem to be solved by the invention]

Due to temperature rise after lighting, etc., the starting point 10a of the light source 10
movement is inevitable.

When this starting point 10a moves, the first condenser lens 16
- The position of the starting point 10a relative to 16-4 changes, and the amount of light incident on the optical fibers 141 to 14-4 becomes non-uniform.

Here, for example, it is assumed that the amount of light incident on the optical fiber 4-1 has decreased.

As a result, the +i degree distribution on the exit surface 15a of the bundling portion 15 becomes non-uniform, as shown by linework a in FIG.

Therefore, the illuminance distribution on the reticle 2 is
The distribution of illuminance of image 5 becomes uneven as shown in
It becomes non-uniform as shown by the line ma in the figure.

As a result, the portion B2-A2 of the wafer 4 is underexposed, resulting in uneven exposure.

SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure apparatus that prevents exposure unevenness even when the starting point of a light source moves.

[Means to solve the problem]

The present invention provides a light source, a wavelength selection means disposed around the light source for selecting light of a specific wavelength necessary for exposure from among the light from the light source, and In an exposure apparatus, the light condensing means is arranged such that the light beam from the wavelength selection means is incident thereon. , a plurality of collecting optical fibers arranged so that the incident light beams are collected together, and a single collecting optical fiber that receives the light fluxes emitted from the collecting optical fibers and emits them all at once. and a condenser lens provided for each of the grouping optical fibers and arranged to condense the light beam emitted from the grouping optical fiber onto the incident surface of the output optical fiber. The light beams emitted from each grouping optical fiber overlap, enter the grouping optical fiber, and are emitted from the grouping optical fiber.

[Effect]

The light beams emitted from the grouping optical fiber overlap and enter the grouping optical fiber, so even if the base point of the light source moves and the amount of light emitted from each grouping optical fiber varies, the grouping optical fiber Although the level of brightness at the exit surface changes, it remains in a similar state over the entire surface.

〔Example〕

FIG. 1 shows an exposure device @20 which is an embodiment of the present invention.

In FIG. 1, parts corresponding to those shown in FIG. 6 are given the same reference numerals.

21 is a light condensing means, and four optical fibers 2 for gathering
2-1 to 22-4, - optical fiber 23 for grouping,
It is composed of four condenser lenses 24-1 to 24-4 and a diffusion lens 25.

The grouping optical fibers 22-1 to 22-4 each have an entrance surface 22-1. ~ 22-4a respectively facing the second condenser lenses 17-~17-4, and forming a substantially inverted circle 1.
It is arranged along the slope of t26.

The grouping optical fiber 23 is disposed vertically with the upper incident surface 23-a approximately aligned with the apex of the inverted cone 26.

The fourth capacitors 24-1 to 24-4 are connected to the exit surfaces 22-2b to 22-4b of the optical fibers 22-1 to 22-4, respectively.
Each optical fiber 22-1 to 22-
The light emitted from 4 is focused.

Optical fibers 22- to 22-4. Lenses 24-1 to 22-
4. and the optical fiber 23 is the optical fiber 22- to 22-
They are arranged in such a positional relationship that the light beams emitted from the optical fibers 22-1 to 22-4 are focused by the lenses 22-1 to 22-4 and focused at one point P on the entrance surface 23a of the optical fiber 23.

Is the diffuser lens 25 optical? It is provided opposite to the exit surface 23b of the fiber 23.

Next, the exposure operation will be explained.

Wavelength selection means 1 among the light emitted from the light source 10 to the surroundings
The light having a wavelength of 429 nm selected by 1 passes through the second condenser lenses 17-1 to 17-4 and enters into the optical fibers 22-1 to 22-4.

The light is guided through each of the optical fibers 22-1 to 22-4 and exits from the exit surfaces 22-, b to 22-4b. The emitted light beams 27-1 to 27-4 are transmitted through condenser lenses 24-1 to 24-1.
24-4, the incident surface 23 of the optical fiber 23
The light is focused at point P on point a.

Therefore, the light beams emitted from each of the optical fibers 22-1 to 22-4 enter the optical fiber 23 in a superimposed state.

The light that has entered in a superimposed state is collected within the optical fiber 23, and in this state is emitted from the exit surface 23b.

The light flux emitted from the exit surface 23b is diffused by the diffusion lens 25, condensed by the third condenser lens 18, and reaches the wafer 4 through the lens 19.

The device pattern 3 is imaged as an image 5 on the upper surface of the wafer 4, and the wafer 4 is exposed.

When the starting point 10a of the light source 10 is at a predetermined position, the amount of light incident on each of the optical fibers 22-1 to 22-4 is equal, and the l! ir! The distribution of 1 is approximately uniform over the entire surface, as shown by ■ in FIG.

Therefore, the distribution of illuminance on the reticle 2 is approximately constant over the entire surface, as shown by line V in FIG.

Therefore, the illuminance distribution of the image 5 is also substantially constant over the entire area as shown by the line 2 in FIG. 5, and the reduced device pattern is uniformly exposed over the entire surface of the wafer 4.

Next, the exposure state when the starting point 10a of the light source 10 moves will be described.

Assume that the starting point 10a moves and the amount of light incident on the optical fiber 22-1 corresponding to the optical fiber 4-1 is reduced.

As a result, only the amount of light emitted from each optical fiber 22-1 is reduced by 10 compared to the amount of light emitted from the other optical fibers 22-2 to 22-4, but the amount of light emitted from each optical fiber 22-2 to
The light beams emitted from the optical fibers 2-4 overlap and enter the optical fiber 23, and at the stage of exiting from the optical fiber 23, the light beams from each of the optical fibers 22-1 to 22-4 are brought together and harmoniously integrated.

Therefore, the brightness distribution of the exit surface 23b is as follows from the line I in FIG.
It becomes lower than the level shown by V, and dimming occurs, but line IV
As shown by a, a substantially uniform state is maintained over the entire surface.

Therefore, the distribution of illuminance on the reticle 2 remains approximately constant over the entire surface, as shown by the line va in FIG. 4, although the level decreases somewhat.

Therefore, as shown by line V[a in FIG. Exposure is uniform over the entire area, and no exposure unevenness occurs. Even if the starting point 10a moves in a direction different from that described above, exposure unevenness is prevented from occurring in the same manner as described above.

〔Effect of the invention〕

As described above, according to the present invention, even if the starting point of the light source moves, exposure unevenness can be prevented from occurring, and it is possible to cope with miniaturization of device patterns.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the exposure apparatus of the present invention, Fig. 2 is an enlarged dimensional drawing of the exit surface of the grouping optical fiber shown in Fig. 1, and Fig. 3 is the injection of the grouping optical fiber. Figure 4 is a diagram showing the illuminance distribution on the reticle in Figure 1. Figure 5 is a diagram showing the illuminance distribution on the wafer in Figure 1. Figure 6 is a diagram showing the illuminance distribution on the wafer in Figure 1. FIG. 7 is an enlarged view of the exit surface of the bundling section in FIG. 6, FIG. 8 is a diagram showing the brightness distribution of the exit surface of the bundling section, and FIG. FIG. 6 is a diagram showing the illuminance distribution on the reticle, and FIG. 10 is a diagram showing the illuminance distribution on the wafer in FIG. In the figure, 2 is a reticle, 3 is a device pattern, 4 is a wafer, 5 is an image, 10 is a mercury lamp light source, 10a is a starting point, 11 is a wavelength selection means, 20 is an exposure device, 21 is a condensing means, 22-- 22-4 is a grouping optical fiber, 23 is a grouping optical fiber, 23a is an entrance surface, 23b is an exit surface, 24- to 24-4 are fourth condenser lenses, 25 is a diffusion lens, 27-1 to 27 -2 indicates the light flux emitted from the collecting optical fiber. Patent Applicant: Fujitsu Ltd. Figure 8

Claims (1)

[Scope of Claims] A light source (10), a wavelength selection means (11) arranged around the light source and for selecting light of a specific wavelength necessary for exposure from among the light from the light source, In an exposure apparatus that includes means (21) for condensing light of a wavelength selected by the selection means, and performs exposure using the light condensed by the condensing means, the condensing means (21) is , a plurality of gathering optical fibers (22-_1 to 22-_4) arranged so that the light beam from the wavelength selection means (11) is incident thereon, and arranged so as to collect the incident light beams.
), and a single grouping optical fiber (23) that receives the light beams (27-_1 to 27-_4) emitted from the grouping optical fibers and outputs them all together (23). A condenser lens (24-_1 to 22-_4) is provided for each of the condenser lenses (24-_1 to 22-_4) and is arranged so as to condense the light beam emitted from the collection optical fiber onto the incident surface of the exit optical fiber. 24-_4)
The light beams emitted from the name collection optical fibers (22-_1 to 22-_4) overlap and are transferred to the name collection optical fiber (22-_4).
3) An exposure apparatus characterized by having a structure in which the light enters the light source and exits from the light source.