JPH01161716A - Pattern transferring apparatus - Google Patents

Abstract

PURPOSE:To prevent a mask from deflecting due to its own weight and to improve transferring accuracy by forming a mask holder of a flat plate to attract and hold the mask. CONSTITUTION:A mask 40 disposed on a mask holder 30 is irradiated with a light or an ultraviolet light, a sample 60 is radiated with the light transmitted through the mask 40, and the pattern 42 of the mask 40 is transferred to the sample. In such a pattern transferring apparatus, the holder 30 is formed of a flat plate to attract and hold the mask 40. For example, the holder 30 is formed by depositing a transparent electrode 32 made of ITO or the like on the lower face of a transparent substrate 31 made of quartz or the like, and a transparent insulating layer made of SiO2 or the like is deposited by a CVD method or the like on the lower face. When a voltage from a DC power source 82 is applied between the mask 40 and the transparent electrode 32 of the holder 30 in a state that the mark 40 is pressed to the lower face of the holder 30, the mask 40 is fixed in close contact to the holder 30 by an electrostatic attraction force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a pattern transfer device, and particularly to a pattern transfer device with an improved mask holder.

(Prior Art) Conventionally, as an apparatus for forming a pattern of an LSI or the like on a sample, a pattern transfer apparatus that projects and exposes a pattern formed on a mask onto the sample has been used. In this apparatus, light is irradiated from above onto a mask attached to the lower surface of a mask holder, and the light transmitted through the mask is projected onto a sample using a lens or the like for exposure.

However, this type of device has the following problems. In other words, the mask holder has an opening in the center so as not to block light, and the mask is fixed to the mask holder at its periphery.As a result, the mask flexes due to its own weight. Sometimes. If the mask is deflected, the imaging conditions on the sample will be disrupted.
This results in a decrease in transfer accuracy. A further problem is that the mask surface is upside down when drawing with an electron beam and when transferring, and in that case, errors due to deflection may double.

On the other hand, in order to solve the above problem, efforts have been made to increase the thickness of the mask to reduce errors caused by mask deflection. However, as the substrate becomes larger and the required precision becomes higher, it is no longer possible to respond as is.

(Problems to be Solved by the Invention) As described above, in the conventional pattern transfer apparatus, there is a problem in that the mask is deflected due to its own weight, and this deflection causes a problem in that the pattern transfer accuracy is reduced.

The present invention has been made in consideration of the above circumstances, and an object thereof is to provide a pattern transfer device that can prevent the mask from bending due to its own weight and improve transfer accuracy.

[Structure of the Invention] (Means for Solving Problems) The gist of the present invention is to prevent the mask from bending by tightly holding the mask on a mask holder.

That is, the present invention provides a pattern transfer device that irradiates a mask placed on a mask holder with light or ultraviolet light, and irradiates the sample with the light that has passed through the mask to transfer the pattern of the mask onto the sample. The mask holder is formed of a flat plate such as an electrostatic chuck plate, and is configured to suction and hold the mask.

(Function) According to the present invention, since the mask is tightly held on the mask holder by an electrostatic chuck or the like, it is possible to prevent the mask from being bent due to its own weight. Furthermore, since there is no need to increase the thickness of the mask, it is fully applicable even to large masks.

(Example) Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a schematic diagram showing a pattern transfer device according to an embodiment of the present invention. In the figure, 10 is a light source, and light emitted from this light source 10 is condensed by a condensing lens 20 and irradiated onto a mask 40 fixed to a mask holder 30. The mask 40 has a light shielding pattern (mask pattern) 42 made of a light shielding member formed on the lower surface of a transparent substrate 41, and the light transmitted through the mask 40 is transmitted to the projection lens 50.
The image is reduced and projected onto the wafer 60 (sample) by, for example, 115. The wafer 60 is placed on a stage 70 that is movable in the X-Y directions, and as the stage 70 moves, a mask pattern is transferred in a step-and-repeat manner.

On the other hand, the mask holder 30 has a transparent substrate 31 made of quartz or the like.
A transparent electrode 32 such as ITO (indium nine oxide) is formed by vapor deposition on the lower surface of the 5i0
A transparent insulating layer such as No. 2 is deposited by a CVD method or the like. In other words, this mask holder 30 constitutes a so-called electrostatic chuck plate. Here, the thickness of the transparent substrate 31 was set to a value that allows sufficient flatness to be obtained, for example, 5as, the thickness of the transparent electrode 32 was set to 10 μm, and the thickness of the transparent insulating layer 33 was set to 1.0 μm. At this time, the attenuation of the light from the light source 10 at the mask holder 30 was so small that it could be ignored.

To electrostatically chuck the mask 40 to the mask holder 30, a switch 81 is inserted between the mask 40 and the transparent electrode 32 of the mask holder 30 while the mask 40 is pressed against the lower surface of the mask holder 30. A voltage from a DC voltage 82 (for example, 100V) is applied. Thereby, the mask 40 is closely fixed to the mask holder 30 by electrostatic attraction.

After the mask 40 is fixed to the mask holder 30, the electrostatic chuck is held even if the switch 81 is turned off.

Note that in order to perform the electrostatic chuck described above, it is necessary to form the mask 40 from a conductor, and for this purpose, the transparent substrate 41 of the mask 40 may be formed from a conductor. In addition, the transparent substrate 4
A transparent conductive film such as ITO may be thinly deposited on the upper surface of 1.

With such a configuration, the mask 40 is attached to the mask holder 3.
Since the mask 40 is closely fixed to the lower surface of the mask 40 by an electrostatic chuck, the mask 40 can be prevented from deflecting due to its own weight. Therefore, the mask 40 could be held flat, and the mask pattern could be accurately transferred onto the wafer 160. Conventionally, a pattern error of 0.25 μm on a mask is 1
15 and was approximately 0.05 μm, but in this example, this could be reduced to approximately zero. Also, 40 masks
Since there is no need to increase the thickness of the mask, the weight of the mask can be reduced and the degree of freedom in mask design can be increased.

Note that the present invention is not limited to the embodiments described above. For example, the light source may emit not only visible light but also ultraviolet light. Further, as the mask holder, a vacuum chuck plate can be used instead of the electrostatic chuck plate. In this case, a flow path for evacuation may be provided in the transparent substrate, and openings communicating with the flow path may be provided at a plurality of locations on the lower surface. Furthermore, although it is generally desirable for the lower surface of the mask holder to be a flat surface, the lower surface of the mask is formed to have a predetermined curved surface,
It is also possible to curve the mask if desired. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As detailed above, according to the present invention, by providing the mask holder with a function such as an electrostatic chuck or a vacuum chuck, it is possible to prevent the mask from bending due to its own weight, Pattern transfer accuracy can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a pattern transfer device, for explaining one embodiment of the present invention. 10... Light source, 20... Condenser lens, 30...
...Mask holder, 31...Transparent substrate, 32...Transparent electrode, 33...Transparent insulating layer, 40...Mask, 4
DESCRIPTION OF SYMBOLS 1... Transparent substrate, 42... Light shielding pattern (mask pattern), 50... Projection lens, 60... Wafer (
sample), 70...stage, 81...switch, 8
2...DC power supply. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (5)

[Claims] (1) In a pattern transfer device that irradiates a mask placed on a mask holder with light or ultraviolet light and irradiates the sample with the light that has passed through the mask to transfer the pattern of the mask onto the sample, the mask holder is A pattern transfer device characterized in that the tool is made of a flat plate and holds the mask by suction. (2) The pattern transfer apparatus according to claim 1, wherein the mask holder is an electrostatic chuck plate. (3) The pattern according to claim 2, wherein the electrostatic chuck plate is formed by forming a transparent electrode on a transparent substrate and forming a transparent insulating layer on the electrode. Transfer device. (4) The pattern transfer apparatus according to claim 1, wherein the mask holder is a vacuum chuck plate. (5) The pattern transfer device according to claim 1, wherein the thickness of the mask is 2 mm or less.