JPH0670960B2 - Blind device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention enables exposure of an arbitrary exposure region by blocking exposure light in an exposure apparatus for manufacturing a semiconductor by printing a mask pattern on a wafer. The present invention relates to a blind device.

[Prior Art] Generally, a blind device used for an optical stepper is
As shown in FIG. 1, under a mask 1 called a reticle, four rectangular blinds 2a to 2d (only two are shown) that move from four sides to surround an exposure area, and the blinds.
It is composed of a positioning setting mechanism system 3 (only one is shown) having a drive source such as a DC servo motor with a rotary encoder that moves 2a to 2d and sets the position at an accurate position.
Since the blinds 2a to 2d are made of a metal such as aluminum for blocking the exposure light L, alignment lights (visible light or He light) for aligning the mask 1 and the wafer 4 with each other.
-Ne (helium-neon) laser etc. are usually used). Therefore, when exposing a part of the device pattern 5 formed on the mask 1 by the blinds 2a to 2d, the light passes through the alignment mark M1 formed around the pattern 5 and is projected. The lens 6 interrupts the alignment light L ′ irradiated on the alignment mark M2 on the wafer 4, and it is impossible to directly align the mask 1 and the wafer 4. For this reason, the mask 1 is first removed without the blinds 2a to 2d.
And the wafer 4 are aligned, the position of the mask 1 is read and held by a position detection system (for example, a linear encoder or a rotary encoder) attached to the drive system of the mask stage 7, and at the same time, the position of the wafer 4 is detected by a laser interference system. After that, the blinds 2a to 2d are moved to predetermined positions and exposed.

[Problems to be Solved by the Invention] Since the conventional blind device cannot pass the alignment light L'as described above, it is impossible to always directly servo the mask 1 and the wafer 4 during exposure. Therefore, after the mask 1 and the wafer 4 are aligned and set at a predetermined position, the position is detected and held by an individual position detection system. Therefore, when the mask stage 7 or the wafer stage 8 on which the mask 1 and the wafer 4 are mounted moves due to thermal deformation or the like, the relative position between the mask 1 and the wafer 4 is deviated, and as a result, the alignment accuracy deteriorates. I had the problem of saying that. This problem was remarkable in the case of the X-ray exposure apparatus in which the exposure time is several minutes to one hour as compared with the optical stepper having the short exposure time. Further, in the case of the X-ray exposure apparatus, the blinds 2a to 2d need to be taken in and out each time the gap and the position are aligned for each exposure, which has a drawback that the processing time per wafer 4 becomes long. Was.

Moreover, since soft X-rays are used as the exposure light in the X-ray exposure, the mask is made of tantalum (Ta) or gold (Au) that absorbs X-rays on a thin membrane made of SiN or BN that transmits X-rays. A device pattern 5 formed of a heavy metal (usually called an absorber) is used. Further, unlike the light exposure L at present, since there is no lens 6 optical system capable of refracting soft X-rays, the exposure is performed by irradiating divergent X-rays emitted from a point light source. Therefore, unlike the case of using parallel light, the transfer pattern has a blur called a penumbra that is proportional to the size of the point light source. In order to reduce this blur amount, the mask stage 7
The mask 1 held on the top and the wafer 4 held on the wafer stage 8 must be as close as possible.
Similarly, the blinds 2a to 2d that block the exposure light must be provided as close to the mask 1 as possible so that the blur becomes small.

Here, the present invention seeks to provide a suitable blind device which is effective in solving and achieving the aforementioned drawbacks and desires of the prior art.

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, in order to limit an exposure area of an exposure apparatus, a blind that blocks exposure light and a positioning set at a predetermined position by moving the blind. In the blind device including the positioning setting mechanism system, the exposure light is blocked, and the alignment light used for aligning the mask and the wafer is used, and the blind is used on the upper side with the mask stage in between. By disposing the mask on the lower side, the mask and the wafer can be arranged as close to each other as possible.

[Operation] The present invention adopts the above-mentioned means, and by using the blind that blocks the exposure light and transmits the alignment light, the mask and the wafer can be directly servoed constantly during the exposure.
The alignment accuracy does not deteriorate due to thermal deformation, etc., and the blind can be placed on the upper side of the mask stage and the mask on the lower side. Therefore, the mask and the wafer can be arranged as close as possible. Made possible

Embodiments Embodiments of the present invention will be described in detail with reference to the drawings.

In the optical stepper shown in FIG. 1, blinds 2a-2d are provided.
Instead of a metal such as aluminum as a material used for, the g-line (436 nm) or i-line (365 nm) that is the exposure light L or the He-Ne that is the alignment light L'that blocks the excimer laser (<300 nm) is used. An orange filter A, a yellow filter B, or a UV filter C having a transmittance distribution with respect to the wavelength as shown in FIG. 2 which transmits a laser (632.8 nm) or visible light (400 nm to 760 nm) is used. By using the blinds 2a to 2d as described above, only the alignment light L'can be passed. Therefore, by setting the alignment 2a to 2d at a predetermined position and performing exposure, only an arbitrary exposure area can be exposed. Yes, and
Since the servo can be performed during the exposure, the alignment accuracy does not deteriorate even if the exposure time is required.

3 and 4 show the case where the present invention is applied to an X-ray exposure apparatus. FIG. 3 is a side view of the X-ray exposure apparatus, and FIG. 4 is a plan view of the same, partially omitted, in which the blinds 2a to 2d are arranged above the mask stage 7 and the mask 1 is arranged below. . In FIG. 3, blinds 2a and 2b provided near the mask 1 are drawn. Blinds 2a-2 shown in FIG.
d is arranged so as to surround the device area α (indicated by diagonal lines) from all sides, and is accurately moved to a predetermined position by the positioning setting mechanism system 3 (only one is shown) that has a drive source such as a DC servo motor with a rotary encoder. Then, the soft X-ray L1 outside the device area α is blocked. This makes the blind 2a ~
When there is no 2d, it is possible to prevent double exposure or quadruple exposure of a corner portion caused by leakage of X-ray L1 through the absorber 9 to the adjacent device region α. Also, XY
By arranging the blinds 2a to 2d so as to cover the alignment marks x1, x2, y arranged on the scribe line on the axis, the alignment mark on the mask 1 becomes X-ray.
Since it can be prevented from being transferred onto the wafer 4 by L1, the mask mark can be arranged on the adjacent device region with the scribe line in between. Therefore, only the wafer mark forming area is required on the wafer 4, and there is an advantage that the mark area can be reduced. further,
Even in the alignment method in which the mask mark and the wafer mark are superposed and aligned with each other, since the mask mark is not transferred onto the wafer mark, the shape of the wafer mark is preserved and the wafer mark can be used for the alignment of the next layer. . In order to perform alignment during exposure, the alignment light L2 needs to pass through the blinds 2a to 2d. The blinds 2a to 2d are plastic plates that are not deteriorated or deteriorated by the glass plate (quartz, Pyrex glass) or exposure light or alignment light. Made of transparent material like wood. Further, a material having a small refractive index and a small thickness is used so that the phase of the light does not largely change due to the transmission of the alignment light L2.

In the embodiment of the present invention, a DC servo motor with a rotary encoder is shown as an example of a drive source for moving the blinds 2a to 2d, but a DC servo motor with a linear encoder or a pulse motor may be used. Although the blinds 2a to 2d have a rectangular shape, they may have a semicircular shape or other shapes, or may be made of a transparent material only in the portion through which the alignment light is transmitted.

[Effects of the Invention] According to the present invention, the blind blocks the exposure light but allows the alignment light to pass through at all times, so that the servo can be performed during the exposure, the alignment accuracy does not deteriorate even in the long-time exposure, and the X-ray exposure is performed. In the case of the apparatus, a remarkable effect is obtained such that the mask and the wafer can be arranged closest to each other.

[Brief description of drawings]

FIG. 1 is a central longitudinal sectional view of a stepper having a blind device, FIG. 2 is a view showing a transmittance characteristic of a blind material with respect to a light wavelength, and FIGS. 3 to 4 are embodiments of the present invention. 1 ... Mask, 2a-2d ... Blind, 3 ... Positioning setting mechanism system, 4 ... Wafer, 5 ... Device pattern,
6 ... Projection lens, 7 ... Mask stage, 8 ... Wafer stage, 9 ... Absorber, A ... Orange filter, B ... Yellow filter, C ... UV filter,
L ... exposure light, L ', L2 ... alignment light, L1 ... X
Line, M1 …… Mask mark, M2 …… Wafer mark, α ……
Device area

Claims (2)

[Claims] 1. A blind device comprising a blind for blocking exposure light and a positioning setting mechanism system for moving and setting the blind at a predetermined position in order to limit the exposure area of the exposure device. A blind device using the blind which transmits alignment light used for aligning a mask and a wafer. 2. A device pattern is formed with a blind that is positioned and set at a predetermined position by a positioning setting mechanism system, shields exposure light, and transmits alignment light used for aligning and setting a mask and a wafer on the upper side. A blind device characterized in that the mask is arranged on the lower side with a mask stage sandwiched between them so that the mask and the wafer can be arranged as close to each other as possible.