JPS58118617A - Macro-photographing device - Google Patents

Abstract

PURPOSE:To obtain a device which can make macro-photographing in such a way that one chip of a photomask having a highly dense pattern is enlarged to the same size of a reticle, by combining an optical system containing a highly precise lens, a deveice system, and a lighting system. CONSTITUTION:The macro-photographing device of this invention is equipped with an X-stage 4 having an opening, through which a transmitting lighting light is passed to a photomask 1 to be photographed, a Y-stage 3, and a mask fitting tool 2. Moreover, a lens system having a lens 17 of 5-20 times magnification, >=300lines/mm. effective resolving power, and >=14mm. diameter effective photographing range, and a high resolution light sensitive dry plate 19 having <=10mu resolution, are provided. This device makes macro-photographing of one chip of the photomask.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus capable of accurately enlarging and photographing a single chip size of a photomask having a high-density light-shielding pattern.

Conventionally, photomask θ using photolithography technology
] The manufacturing method is to first create a one-chip pattern (this is called a reticle) that is 10 times larger than the final pattern using a pattern generator, and then perform 1//1oIICm copying and multi-sided printing using a step-and-repeater. We are manufacturing masks. Pattern designers often wish to visually inspect the pattern for the presence or absence of defects, and in such cases, the reticle, which is created in the pre-processing stage of photomask manufacturing, is coated with photographic film. Zoom up (usually 20x, hence the final photo)
Masktsu 20 o times) Shiy,,: I was using things.

As I said, the reticle has a 310x Photomask α pattern, so enlarging such a large pattern using a conventional enlarging camera for plate making or an interrogator photography device is particularly problematic. did not occur.

However, photomasks for VLSI and solid-state imaging devices require extremely high-density patterns; An exposure device may directly draw a pattern at the same magnification as the pattern on the photomask itself. Since such a method does not produce a reticle with a 10x pattern, it is necessary for a designer to take an enlarged photograph of the photomask in order to visually inspect the manufactured photomask. However, photomasks generally have a high-density pattern, which is 10 times as dense and fine as a reticle, and the method of accurately enlarging and reproducing such a high-density photomask is limited by the limitations of the equipment and optical system. It is extremely difficult due to

For example, regarding a conventional device that magnifies a reticle (10x pattern), its resolving power is at least 25
The limit is micron width, 10 micron square in rectangle,
This is completely inadequate as a magnifying imaging device for a photomask for ultra-LS, which mainly consists of a rectangular pattern of about 4 to 5 microns.

In order to solve these problems, the present invention combines a high-precision optical system (especially lenses), a device thread 2, and an illumination thread to make a single chip of a photomask with a high-density pattern the same as a reticle. He devised a device that could magnify images by 5 to 20 times.

Since this is a photomask, a transmitted illumination thread is used as the illumination device, and the X and Y stages and photomask fixtures, which can set one chip of the photomask at the center of the optical axis, all have openings through which the illumination light can pass. A magnification of 5 to 2 with an effective imaging range of 14 m or more in diameter and an effective resolution of line patterns of 300 m or more per millimeter.
This is a magnification photographing device equipped with a 0x lens thread and a photosensitive dry plate with a resolution higher than 10 microns. 1 showing an embodiment of the present invention, a more detailed explanation will be given below. A photomask (1) to be photographed in an enlarged manner is held by a mask fixture (2), and this mask fixture (2)
is fixed to the Y stage (3). The Y stage (3) is slidably installed on the rail (5) of the X stage (4), and the X stage (4) is similarly installed on the mirror stand (6:Q) rail (7). Each stage (3) and (4) comes with a moving handle (81 (91); in Figure 1, the X stage (4) is supported by a moving screw α0).

Moreover, it is shown that it is slid by the rotation of this moving screw (10σ). Is the Y stage (3) also this X stage? (It has a sliding mechanism similar to 41.

The effective movement range of the X, Y stage f3H41 is determined by the thickness of the recent photomask. That is, recent photomasks are 4 to 6 inches square, and in order to be able to photograph the chip at any position on such a photomask, the movement range of the X and Y stage [31 (4) is 100 to
It will be approximately i5QllIm.

Therefore, mask fixture (2), X, Y stage (3) (41
The width of the opening to be drilled is also adjusted so that the illumination light from below can pass through no matter where the stage moves.
It will be about 1100W to 150Wrln angle.

On the other hand, the illumination string consists of a high-power light source Qll such as a mercury lamp, a collimator lens O2, and a wavelength cut filter 0.
3) and electromagnetic shutter circle and glass fiber (1
5) are connected in series to guide the light from the light source to the photomask (1!
) is provided with one diffuser plate (16) for uniformizing the light. It is desirable that the light source and light collecting thread be strong.
Specifically, the amount of light σ) on the exposed dry plate Q1 side is practically required to be 5×10 mW/m1 or more.

If the amount of light is less than that, the exposure time will be too long, which is undesirable from the viewpoint of contrast and the like.

Glass fiber (15) is not suitable for mirror stands (15) due to equipment constraints.
It is useful when the light source (11) cannot be installed directly under the mirror stand (6) due to the structure of the device.
It is natural that the glass fiber (15) can be omitted if the Ill can be used. Alternatively, a concave mirror may be installed behind the light source (Ill) instead of the collimator lens (121).

Next, talking about the lens aη, as I forgot to mention, the effective resolution is more than 5QC1/w in a line pattern, so it can resolve lines with a small line width of 167 microns at equal intervals. In addition, the size of one photomask chip can be assumed to be up to 10 angles these days, so a diameter of 14 angles is required to photograph it.It is better to use a small lens.

As a specific example of the lens αη that satisfies such requirements, the present inventor has proposed 5-planarl, manufactured by West Germany Raff 4F;
6150 Cabinet, 10:1.14■da is proposed. The F value of this lens is 16, and the line pattern is 500i.
It has an effective resolution of /1111.

As for the photosensitive drying plate α9 installed at the top of the lens barrel 0&, silver halide glass drying plates are often praised for their high photosensitivity, but photoresist is superior in terms of recitation resolution.

A powerful light source (11) can be used, and there is no photosensitive dry plate! If an exposure amount of about 5 y (W/all) can be obtained on the J plane, the photoresist is transferred to a photosensitive dry plate a.
It is also possible to use it for 9. Since the resolution of the photosensitive dry plate is to copy a 1 micron pattern of a photomask film, a high resolution dry plate αl of 10 microns or less is used with a lens magnification of 10 times.

The lens barrel 08 has a light-shielding cover (A) on the bottom and is supported by the overall support (21), and the joint part (221 has a sharp point) with a focusing screw c that allows slight movement up and down. ! 31 is attached.

According to the magnification photographing device of the present invention, it is possible to magnify and photograph a photomask produced by drawing directly with an electron beam exposure machine without using a reticle, magnifying it 5 to 20 times.
As a result, it is possible to enlarge and photograph a line pattern of 2 microns and a rectangular pattern of fine patterns with a radius of 5 microns without damaging the shape. t is the smallest pattern possessed by recent photomasks for (super) LSIs, which is a rectangular pattern with an angle of 4 to 5 microns σ.
] It can be said that the performance is sufficient for enlarging and photographing fine patterns.

The image, which is 5 to 20 times larger than the one-chip photomask obtained by the magnifying photographing device of the present invention, is further enlarged by about 10 to 20 times using a normal magnifying photographing device (finally 200 times the original size). degree) The presence or absence of pattern defects can be examined by visually observing lateral distortion.

Examples of the present invention will be described below, but the present invention is not limited thereto, of course.

〔Example〕

In the magnifying photographing apparatus shown in FIG. 1, one chip of a 4-inch square photomask was photographed at a magnification of 10 times using an article having the specified physical properties as shown below.

ox,
．． 615011!11 Magnification 10x, effective shooting range 14cm diameter Effective resolution 500 lines / sea bream 0 light sensitive dry plate = 4.5 inch square high resolution dry plate Product name [
Sakshi U N J (manufactured by /J-Nishiroku Shagu Kogyo ■) Resolution 10 microns or less 0 Light intensity on dry plate surface 0005...W/CIItO Exposure time
A 10x photomask pattern was obtained according to specifications such as 60 seconds or more, and this was further enlarged 20x using a normal magnifying photographing device to obtain a 200x enlarged image on the photographic film surface.

Even though the obtained enlarged photographic image was a rectangular pattern with an original size of 4 microns square, its corners were at almost right angles and were not rounded (and had a satisfactory shape).

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an embodiment of the enlarged photographing device σ of the present invention. (11...Photomask (2)...Mask fixture (3)...X stage (4)...X stage
(6:...dressing table (11)...yt, lungs (19...
・Glass fiber 061... Diffusion plate 071...
・Lens 0 seconds... Lens barrel 0... Photosensitive dry plate)
... Pillar patent applicant Toppan Printing Co., Ltd.

Claims (1)

[Claims] (1) a. An X and Y stage and a mask fixing device, each having an opening that allows transmitted illumination light to pass through a photomask of an object to be photographed. b9 Magnification 5 to 20 times, effective resolution of 600 lines/square or more, effective imaging range of 14 or more diameter lens thread, high-resolution photosensitive dry plate with C0 resolution of 10 microns or less, and the above a, b, and c. A device for enlarging and photographing a single chip of a photomask.