JPH0496214A - Exposure treatment device - Google Patents

Abstract

PURPOSE:To efficiently use both of an X-ray stepper and an optical stepper by using only an SOR light source and using a proper wavelength selecting means. CONSTITUTION:X-rays that are passed through a Be film 11 of SOR light 3a taken out from a port 2a of an SOR light source 1 is supplied to an X-ray stepper 12. Further, light (g-rays) having different wave length from that of X-rays that are passed through an optical filter 21 of the SOR light 3b taken out from the port 2b is supplied to an optical stepper 22. Thus, in this embodiment, light having the optimal wave length to the respective steppers (exposure devices) is taken out from SOR light radiated from the different ports 2a, 2b of the single SOR light source 1 by a wave length selecting means 11, 12 for being used as exposure light in order to constitute an exposure treatment device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an exposure processing apparatus, and particularly to an exposure processing apparatus that uses synchrotron radiation (Synchrotron radiation).
The present invention relates to an exposure processing apparatus suitable for manufacturing semiconductor devices using a light source means that emits light in a wide wavelength range from X-rays to visible light, such as 5OR diation (abbreviated as 5OR).

(Prior Art) In the production of current semiconductor integrated circuits, in most cases UV light (for example, G-line, wavelength 436 nm) is used as an exposure light source, the wafer surface is divided into multiple regions, and a mask (reticle) is used for each divided region. An exposure apparatus (hereinafter referred to as an "optical stepper") using a so-called step-and-repeat method is used, in which the process of aligning the wafer with the wafer and performing exposure is repeated multiple times.

One production of a typical semiconductor integrated circuit involves repeating such an exposure process 10 to 20 times. Each exposure process at this time is performed by an optical stepper that satisfies predetermined line width accuracy and alignment accuracy.

FIG. 5 is a schematic diagram of the main parts of the optical system of such a conventional optical stepper.

In the figure, light emitted from a high-pressure mercury lamp 51 is transferred to a condenser lens 52-1 and a mirror Ml.

UV light (for example, G-line light) is incident on the optical filter 52-2 through M2, and the UV light (for example, G-line light) is
It is only passing through. And the optical filter 52-
The incoming light from the UV light source 2 is focused by lenses 52-3 and 52-4, and the surface of the mask 53 is irradiated with the UV light. Then, the circuit pattern on the surface of the mask 53 illuminated with the UV light is reduced and projected by the projection optical system 54 onto the surface of the wafer 55 placed on the wafer stage 56.

Among such exposure apparatuses, exposure apparatuses that use X-rays as a light source have recently been attracting attention for VLSIs using submicron patterns.

When using X-rays as an exposure light source, there is currently no suitable optical system (projection lens) for X-rays, so it is necessary to place the mask and wafer in close contact with each other, or to place them close to each other to achieve isotropic illumination. There is.

Exposure bag Wf X-ray stepper that uses such X-rays)
In order to transfer a submicron pattern, it is necessary to use a mask with a submicron pattern formed at the same magnification, and in general, considering the large diameter of the wafer, it is difficult to create a mask that exposes the entire wafer at once. Therefore, there is currently a tendency to adopt a step-and-repeat method.

In a step-and-repeat type exposure apparatus (hereinafter referred to as rX-ray stepper) that uses X-rays as exposure light, an X-ray tube or a synchrotron radiation light source (hereinafter referred to as rsOR light OR) is used as a light source means. Conceivable.

This SOR light source is described in detail, for example, in the publication "Synchrotron radiation and its applications" published in the March 989 issue of Obtronics.

The SOR light source has the following advantages when used as an X-ray stepper.

(a) The parallelism of the X-ray beam is good, so transfer errors such as penumbra blur and geometric errors are small.

(b) Compared to other X-ray sources, the light intensity is high and high productivity can be obtained.

(c) Since the emission wavelength bandwidth extends over a wide range from X-rays to visible light, there is a high degree of freedom in selecting the wavelength of the light to be used.

(d) Lifespan is semi-permanent.

(Problems to be Solved by the Invention) When manufacturing a VLSI for submicron patterns, various exposure processes are often performed for about 10 to 20 times. However, in many cases, not all exposure processes require exposure that requires submicron precision, but only a portion of the exposure process targets submicron exposure.

Therefore, applying high-precision alignment and exposure for submicron exposure to all exposure processes becomes extremely inefficient in terms of equipment cost and productivity.

For this purpose, it is conceivable to use an X-ray stepper and an optical stepper together depending on the purpose.

However, the lifespan of high-pressure mercury lamps, which are currently widely used in optical steppers, is approximately several hundred hours.

For this reason, in exposure equipment that uses a high-pressure mercury lamp, it is necessary to replace the high-pressure mercury lamp when it reaches the end of its life.This requires either stopping the exposure operation each time, or causing uneven illuminance on the mask surface and reducing the resolution line width. In order to prevent this, it is necessary to place the high-pressure mercury lamp in a predetermined position with high precision.

Generally, such work requires a lot of time and has the problem of reducing the through foot.

The present invention uses only the above-mentioned SOR light source as a light source means,
Another object of the present invention is to provide an exposure processing apparatus that can efficiently utilize both an X-ray stepper and an optical stepper by using an appropriate wavelength selection means and has excellent productivity.

(Means for Solving the Problems) The exposure processing apparatus of the present invention uses a wavelength selection means to select a plurality of lights having different wavelengths from light in a predetermined wavelength band emitted from a single light source means, and The present invention is characterized in that a plurality of lights having different wavelengths are each guided to an exposure device.

In addition, the present invention includes a single light source that emits light in a predetermined wavelength band, and a plurality of lights that have different wavelengths selected from the light emitted from the light source and used as exposure light. It is characterized by being equipped with an exposure device.

Further, a synchrotron radiation light source is used as the single light source means, and the plurality of lights having different wavelengths are extracted from one or more ports of the synchrotron radiation light source and a spatial beam splitting element or a wavelength splitting element is used. It is characterized by the fact that it is obtained through

(Example) FIG. 1 is a schematic diagram of main parts of a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a light source means, which consists of a light source that emits synchrotron radiation light (hereinafter referred to as rsOR light OR), which emits white light with sharp optical properties in a wide wavelength range from X-rays to visible light. (hereinafter referred to as rsOR light J).

Figure 4 shows the SOR emitted from the SOR light source 1 of this embodiment.
FIG. 2 is an explanatory diagram of an example of wavelength distribution of light. In FIG. 4, the horizontal axis indicates the wavelength of light in logarithmic coordinates. The vertical axis shows the unit hunt width, unit time, and number of photons per unit solid angle in logarithmic coordinates. As shown in FIG. 4, it has a peak around wavelength 10, and decreases rapidly on the short wavelength side, but gradually decreases on the long wavelength side until beyond the visible light region.

Returning to FIG. 1, 28 to 2d are ports, which serve as outlets for the SOR light emitted from the SOR light source, and usually 10 to 20 ports are provided per SOR light source. In FIG. 1, only four are shown for simplicity. The SOR light is extracted from each port along the electron rotation trajectory.

3a (3b) is the SOR light taken out from port 2a (2b). Note that the SOR light has the same wavelength distribution no matter which port it is extracted from.

Reference numeral 11 denotes a Be (beryllium) film as a wavelength selection means, which allows X-rays with a spectrum width suitable for an X-ray stepper to pass through.

In this embodiment, it is made of a material that minimizes optical loss in the X-ray region. This is because if the optical loss is large, the amount of X-rays supplied to the X-ray stepper will be reduced and the heat loss will be large, resulting in a shortened lifespan of the film. The Be film 11 also has the function of maintaining the SOR light source in a high vacuum.

12 is an X-ray stepper, which is an SOR light source.
Using the X-rays that have passed through Be1ij as exposure light, the circuit pattern on the mask surface is transferred and phosphorized onto the wafer surface as proposed in, for example, Japanese Patent Application Laid-Open No. 6-114529). I'm here.

Reference numeral 21 is an optical filter as a wavelength selection means, which uses light suitable for an optical stepper, such as g-line (tl length = 436n).
In this embodiment, which allows only the light of wavelength m) to pass through, the loss of light of the g-line is minimized, and a material that blocks light of other wavelengths is used.

22 is an optical stepper, and the SOR from the SOR light source is
The circuit pattern on the mask surface is transferred onto the wafer surface using the light (g-line) that has passed through the optical filter 21 as exposure light, as proposed in, for example, Japanese Patent Application Laid-Open No. 2-100311. There is.

In this embodiment, among the SOR light 3a extracted from the SOROR light source tool 2a, the X-rays that have passed through Beill are
The line stepper 12 is supplied with the line. Also, out of the SOR light 3b taken out from the port 2b, the light (g-line) having a different wavelength from the X-ray that has passed through the optical filter 21 is sent to the optical stepper 2.
2.

In this way, in this embodiment, the wavelength selection means (11, 21) selects the optimal wavelength for each stepper (exposure device) from the SOR light emitted from the ports (2a, 2b), which is a single SOROR light source device. The exposure processing apparatus is configured to extract light and use it as exposure light.

Therefore, the optical stepper 22 of this embodiment does not require the high-pressure mercury lamp that has been used in the past, and has the advantage of eliminating the need for associated maintenance and adjustment.

According to this embodiment, the intensity of the SOR light near the g-line (436 nm) is about 1/2 of the intensity in the wavelength region used for the X-ray stepper=12, as shown in FIG. X stepper 1
2 and the resist sensitivity suitable for the optical stepper 22, there is not much difference in exposure time.

In this embodiment, the wavelength selection means (11, 21) are provided independently from each stepper, or the wavelength selection means may be provided integrally inside each stepper.

Figure #12 is a schematic diagram of the main part of the second embodiment of the present invention. In FIG. 2, the same elements as those shown in FIG. 1 are given the same reference numerals.

In this embodiment, the SOR light 3 taken out from one port 2a of the SOR light #i1 is transmitted through a spatial light beam splitting element 23 consisting of a reflecting mirror with a light-transmitting hole in the center.
It is divided into two lights: a and reflected light 3b.

Of these, the transmitted light 3a passes a predetermined X-ray through Bellll and is guided to the X-ray stepper 12. Further, after the reflected light 3b is condensed by a condenser lens 24, only a predetermined light (for example, g-line light) is passed through an optical filter 21 and guided to an optical stepper 22.

In this embodiment, the SOR light from one port 2a of one SOROR light source is spatially split into two lights using the spatial beam splitting element 23, and each stepper (
By supplying light with an optimal wavelength distribution to an exposure device (exposure device), the SOR light from the SOR light source is effectively used when the number of ports is limited.

FIG. 3 is a schematic diagram of main parts of a third embodiment of the present invention. Third
In the figure, the same elements as those shown in FIG. 1 are given the same reference numerals.

In this embodiment, the SOR light taken out from the port 2a of the SOROR light source transmits light in the X-ray region on the short wavelength side used in the X-ray stepper, and light in the wavelength region on the long wavelength side used in the optical stepper. The transmitted light 3a and the reflected light 3b are separated by the wavelength division element 25 having spectral characteristics such as to reflect the transmitted light 3a and the reflected light 3b.
It is divided into two lights.

Of these, the transmitted light 3a that has passed through the wavelength division element 25 is Be
X-ray stepper 1 passes a predetermined X-ray through
The light is guided to 2. Further, the reflected light 3b reflected by the wavelength division element 25 is guided to the optical stepper 22 through an optical filter 21, allowing only a predetermined light (for example, g-line light) to pass therethrough.

In this embodiment, the wavelength division element 25 and Be1i11 may be integrated.

If a coating film that reflects the UV light region is applied to Beill, the entire device can be miniaturized. In particular, if the wavelength division element 25 is configured by coating a Be substrate with a coating film that reflects only the g-ray light, the optical filter 21 can be omitted, and the wavelength division element 25 can have three functions. The whole can be made smaller and simpler.

In each of the above embodiments, the single light source means is not limited to an SOR light source as long as it emits light in a predetermined wavelength band, but any light source that emits light in the X-ray region and visible region can be used. A light source may also be used.

(Effects of the Invention) According to the present invention, the wavelength selection means selects and guides light of the optimum wavelength to be used for each stepper from light in a predetermined wavelength band emitted from a single light source means such as an SOR light source. By using light, it is possible to achieve an exposure processing apparatus that can perform efficient exposure processing in both an X-ray stepper and an optical stepper, for example.

In particular, since the high-pressure mercury lamp conventionally used as an optical stepper is no longer required, it is possible to achieve an exposure processing apparatus that has the advantage of eliminating the need for adjustment of the light source position and maintenance/inspection time.

[Brief explanation of the drawing]

1, 2, and 3 are schematic diagrams of the main parts of the first, second, and third embodiments of the present invention, respectively. FIG. 4 is an explanatory diagram of the emission spectral characteristics of the SOR light source. FIG. 2 is a schematic diagram of main parts of an optical stepper. In the figure, 1 is an SOR light source, 2a to 2d are photo sources, and 3 is an SO light source.
R light, 3a is X-ray, 3b is G-line light, 11 is Be1li
i, 12 CX wA block 121 is an optical filter, 22 is an optical stepper, 23 is a spatial beam splitting element T
, 24 are a condensing lens and a wavelength division element.

Claims (6)

[Claims] (1) A wavelength selection means selects a plurality of lights with different wavelengths from light in a predetermined wavelength band emitted from a single light source means, and guides each of the selected lights with different wavelengths to an exposure device. An exposure processing apparatus characterized in that: (2) A single light source means that emits light in a predetermined wavelength band and a plurality of exposure devices that select light of different wavelengths from the light emitted from the light source means and use them as exposure light. An exposure processing apparatus characterized by comprising: (3) The exposure processing apparatus according to claim 1 or 2, wherein a synchrotron radiation light source is used as the single light source means. (4) The exposure processing apparatus according to claim 3, wherein the plurality of lights having different wavelengths are extracted from different ports of the synchrotron radiation light source and then selected through the wavelength selection means. (5) The plurality of lights having different wavelengths are extracted from one port of the synchrotron radiation light source and are obtained through a spatial beam splitting element or a wavelength splitting element. Exposure processing equipment. (6) The exposure processing apparatus according to claim 1 or 2, wherein one of the plurality of exposure devices is an exposure device that uses X-rays.