KR20230174667A - An electric potenrial barrier module with heat transfer prevenstion function and a lithography apparatus including the same - Google Patents

Abstract

The present invention relates to an electrical potential barrier module having a heat transfer prevention function and a lithography device including the same, and specifically to an electrical potential barrier module capable of performing the function of a pellicle in a lithography device and a lithography device including the same. will be.

Description

Electrical potential barrier module with heat transfer prevention function and lithographic device including the same

The present invention relates to an electrical potential barrier module having a heat transfer prevention function and a lithography device including the same, and specifically to an electrical potential barrier module capable of performing the function of a pellicle in a lithography device and a lithography device including the same. will be.

When manufacturing semiconductor devices, a method called photolithography is used to pattern a semiconductor wafer. In photolithography, a photomask is used as a patterning original, and the pattern on the photomask is transferred to the wafer.

However, if dust attaches to the photo mask, light is absorbed or reflected due to the dust, causing damage to the transferred pattern, resulting in a decrease in the performance or yield of the semiconductor device.

Therefore, these works are usually performed in a clean room, but since dust exists even in a clean room, a method of attaching a pellicle is used to prevent dust from attaching to the surface of the photo mask.

In this case, the dust is not attached directly to the surface of the photo mask, but is attached to the pellicle film. In the lithography process, the focus is aligned with the pattern of the photo mask, so the dust on the pellicle is out of focus and is not transferred to the pattern. there is.

The pellicle must have good exposure light transmittance, so it is composed of a very thin film. A pellicle with a thin film structure can cause damage or sagging of the thin film due to external impact or stress on the thin film itself.

Since such damage or sagging can distort the image during the pattern transfer process, it is necessary to maintain the mechanical strength of the pellicle thin film to maintain a complete flat state without sagging or damage.

For this purpose, a method is used to prevent distortion of the pellicle thin film by applying appropriate tension (Tensile Stress) to the thin film itself or by additionally forming a reinforcing layer. This method not only causes complexity in the pellicle manufacturing process, but also causes the reinforcement layer to be damaged. There are many difficulties in developing pellicle for extreme ultraviolet lithography, such as the problem of deterioration of the characteristics of the pellicle thin film due to addition.

Therefore, there is a need to develop a foreign matter prevention module with a new structure that can replace the function of the pellicle described above and a lithography device including the same.

The electrical potential barrier module and the lithographic apparatus equipped with the same according to an embodiment of the present invention aim to solve the following problems in order to solve the above-mentioned conventional problems.

An electric potential barrier module and lithography device that can minimize the inflow of foreign matter into the mask side without using a conventional physical pellicle to prevent foreign matter from the mask side are provided.

In addition, the aim is to provide an electric potential barrier module and a lithography apparatus that can minimize the impact that may occur on other components inside the lithography apparatus, such as a mask, due to heat generated from the electric potential barrier module.

The problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the description below.

An electrical potential barrier module with a heat transfer prevention function according to an embodiment of the present invention relates to a barrier module for blocking the inflow of foreign substances into a mask disposed at the top inside the chamber of a lithography apparatus, wherein the barrier module is configured to block the mask from entering the mask. An electric potential barrier is formed by emitting an electron beam to the lower area of , but is configured to prevent heat generated from the barrier module from being transferred to the mask.

A filament that generates an electron beam; a housing formed to accommodate the filament inside, and having a slit formed in the longitudinal direction to emit the electron beam in a direction parallel to the bottom of the mask; and a cooling means for cooling the housing.

It is preferable that a guide part is formed in the housing to guide the direction of light generated from the filament in a preset direction.

The guide portion is formed to protrude in an area around the slit of the housing, and the amount of protrusion of the guide portion is preferably determined based on at least one of the relative position between the barrier module and the mask and the size of the mask.

A lithographic apparatus according to an embodiment of the present invention includes a chamber whose interior is maintained in a vacuum state; a light source unit disposed within the chamber and generating light for lithography; a mask disposed at the top of the chamber; An optical system that transmits the light generated by the light source unit to the mask; and a barrier module that emits an electron beam to a lower region of the mask to form an electrical potential barrier to block the inflow of particles into the mask, and is configured to prevent heat generated in the barrier module from being transferred to the mask. .

The barrier module includes a filament that generates an electron beam; a housing formed to accommodate the filament inside, and having a slit formed in the longitudinal direction to emit the electron beam in a direction parallel to the bottom of the mask; and a cooling means for cooling the housing.

It is preferable that a guide part is formed in the housing to guide the direction of light generated from the filament in a preset direction.

The guide portion is formed to protrude in an area around the slit of the housing, and the amount of protrusion of the guide portion is preferably determined based on at least one of the relative position between the barrier module and the mask and the size of the mask.

An electrical potential barrier module with a heat transfer prevention function according to an embodiment of the present invention and a lithographic device including the same emit an electron beam to the lower area of the mask to form an electrical potential barrier, thereby preventing foreign matter flowing inside the chamber from flowing toward the mask. The effect of preventing inflow can be expected.

In addition, by being configured to prevent the high temperature heat of the electrical potential barrier module from being transmitted, the effect of minimizing the effect on other components such as the mask of the lithography apparatus can be expected.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description below.

1 is a diagram schematically showing a lithography apparatus according to an embodiment of the present invention.
Figure 2 is a schematic perspective view of an electrical potential barrier module with a heat transfer prevention function according to an embodiment of the present invention.
Figures 3 and 5 are cross-sectional views taken along line A-A' of Figure 2.
Figure 4 is a diagram showing the emission situation of light generated from the filament according to the embodiment of Figure 3.
Figure 6 is a diagram showing the emission situation of light generated from the filament according to the embodiment of Figure 5.

Preferred embodiments according to the present invention will be described in detail with reference to the attached drawings, but identical or similar components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted.

Additionally, when describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted. In addition, it should be noted that the attached drawings are only intended to facilitate easy understanding of the spirit of the present invention, and should not be construed as limiting the spirit of the present invention by the attached drawings.

The present invention relates to a technical feature for preventing particles such as dust moving inside a chamber from moving to the other side of the barrier module, that is, the mask side, by using a barrier module composed of a potential barrier rather than a physical barrier. In particular, the present invention relates to technical features such as dust. The movement of particles is not blocked by physical collision with the barrier module, but by the electrical potential barrier.

In this way, the barrier module that forms an electrical potential barrier is used in a lithography device to prevent particles such as dust located in a chamber such as a lithography light source from moving to the mask, thereby preventing foreign matter from entering the EUV lithography device in a physical manner. It becomes possible not to use a pellicle to prevent .

Hereinafter, the lithography apparatus and the electrical potential barrier module with a heat transfer prevention function according to this embodiment will be described with reference to FIGS. 1 to 6.

As shown in FIG. 1, the lithography apparatus according to an embodiment of the present invention includes a chamber 100, a light source unit 200, a mask 300, an optical system 400, a wafer stage 500, and a barrier module 600. It is designed to include

The chamber 100 performs the function of accommodating each component of the lithography apparatus and must be closed to the outside to prevent the inflow of foreign substances from the outside. In particular, in the case of a lithography process using an EUV light source, the EUV light is absorbed in the air. In order to minimize this, it is preferable that the inside of the chamber 100 is maintained in a vacuum state.

The light source unit 200 performs a function of generating light for a photolithography process, and the light source unit 200 of the lithography device according to an embodiment of the present invention generates EUV light 10 for forming fine patterns. desirable.

The EUV light 10 generated in the light source unit 200 is transmitted to the mask 300 on which the fine circuit pattern is formed through the first optical system 400a, and the EUV light 10 passing through the mask 300 is transmitted to the second optical system 400a. It is delivered to the wafer placed on the wafer stage 500 through 400b, and at this time, the photosensitive material coated on the wafer reacts with the EUV light 10 to form a pattern on the wafer.

Meanwhile, in the case of EUV light 10, as described above, since its wavelength is very short, it is easily absorbed, so the optical system 400 including the first optical system 400a and the second optical system 400b is used in a conventional lithography device. It is preferable that it consists of at least one reflector rather than the lens used.

The barrier module 600 is configured to prevent particles such as dust inside the chamber 100 from entering the mask 300, and emits an electron beam to the lower area of the mask 300 to prevent particles from entering the mask 300. Performs a blocking function.

That is, the barrier module 600 is configured to form an electric potential barrier by an electron beam at the bottom of the mask 300, thereby preventing foreign substances from settling on the mask 300 even without a separate pellicle, which is a conventional physical barrier. It becomes possible.

This barrier module 600 may be configured to include a filament 610, a housing 620, and an anode 630, as shown in FIGS. 2 and 3.

In particular, the filament 610 is made of tungsten, etc., and can be formed into a long shape in the longitudinal direction. When the filament 610 is heated to a high temperature by applying a current to the filament 610, it is bound to the surface of the filament 610. Electrons may escape and form an electron beam.

The anode 630 performs the function of accelerating the electron beam, and the housing 620 accommodates the filament 610 and the anode 630 inside, and a longitudinal slit 621 is formed so that the electron beam can be emitted to the outside. It can be.

The electron beam that has passed through the slit 621 forms a planar electrical potential barrier 20 parallel to the bottom of the mask 300 as shown in FIGS. 2 and 3, thereby allowing particles located below to move toward the mask 300. Entry can be prevented.

Specifically, if particles such as dust inside the chamber 100 have a negative (-) charge, they cannot pass through the electrical potential barrier 20 of the barrier module 600 and move toward the mask 300.

In addition, even if particles such as dust inside the chamber 100 carry a positive (+) charge or do not carry a charge, when they move near the electric potential barrier 20 composed of an electron beam, the particles acquire a negative (-) charge. Therefore, it cannot move toward the mask 300 due to the electrical potential barrier 20 of the barrier module 120.

Meanwhile, as described above, in order to form an electron beam, a current is applied to the filament 610 and the filament 610 is heated to a high temperature. At this time, the temperature of the filament 610 rises to about 2700°C, and this high temperature causes lithography It may have a negative effect on the internal structure, especially the mask 300.

In order to prevent this problem, it is desirable to provide a cooling means 640 for cooling the housing 620 in the barrier module 600, as shown in FIG. 3.

This not only has the effect of suppressing heat conduction toward the mask 300, but also serves to protect the housing 620 by cooling it, and also has the effect of preventing heat radiation caused by the high temperature housing 620. You can.

In particular, considering that the chamber 100 is sealed as described above, the cooling means 640 should be configured as a water-cooled type rather than an air-cooled type. The cooling means 640 includes an inlet 641 through which the cooling fluid flows, and It may be provided with an outlet 642 through which cooling fluid that has completed heat exchange with the housing 620 flows out.

However, considering the high temperature of the filament 610, it is difficult to sufficiently reduce the heat of the barrier module 600 with the cooling means 640 alone, so additional measures to minimize heat transfer from the barrier module 600 to the mask 300 are required. This is required.

Meanwhile, heat is transferred by convection, conduction, and radiation. Considering that the inside of the chamber 100 of the lithography apparatus is in a vacuum state, the heat of the barrier module 600 is transmitted through convection. It will not be able to be transmitted to the mask 300.

In addition, the mask 300 and the barrier module 600 are fixedly installed on the inner side of the chamber 100. In this case, heat from the barrier module 600 may be conducted to the mask 300 along the chamber 100, but lithography Considering that the device itself has a high thermal capacity and is equipped with various cooling devices to maintain the temperature of the expensive lithography device itself at a constant temperature, the heat of the barrier module 600 transferred by conduction is transmitted to the mask 300. It won't have much of an impact.

Therefore, an embodiment is required to minimize heat transfer only by radiation from the barrier module 600 to the mask 300.

Radiation is a method in which heat is transferred by light without an intermediary, and as shown in FIG. 4, the light generated from the filament 610 radiates to the outside of the barrier module 600 through the slit 621 of the housing 620 ( emission) and reaches the mask 300, and in order to minimize heat transfer by radiation, the light from the filament 610 must be prevented from being irradiated directly toward the mask 300.

For this purpose, it is preferable that a guide portion 622 be formed in the housing 620 of the barrier module 600 to guide the direction of light generated from the filament 610 in a preset direction rather than toward the mask 300.

This guide portion 622 is preferably formed to protrude in the area around the slit 621 of the housing 620, as specifically shown in FIG. 5, and the amount of protrusion of this guide portion 622 is determined by the barrier module 600. ) and the relative position between the masks 300 and the size of the mask 300.

That is, when the guide portion 622 is formed according to the protrusion amount determined in consideration of the relative position between the barrier module 600 and the mask 300 and the size of the mask 300, the filament 610 as shown in FIG. 6 Since light is not transmitted to the mask 300, heat transfer by radiation from the barrier module 600 to the mask 300 does not occur.

When the barrier module 600 is configured as in the embodiment of the present invention, particles such as dust present in the chamber 100 are blocked from moving to the mask 300 by an electrical potential barrier rather than a physical barrier, so that the lithography process Not only is dust prevented from getting on the mask 300, but it is also possible to minimize the transfer of heat generated during the electron beam emission process of the barrier module 600 to the mask 300.

As a result, the lithography device according to the present invention does not require a pellicle, so the complicated process for manufacturing the pellicle can be omitted. Furthermore, unlike the pellicle, the barrier module 600 can be used semi-permanently, thereby reducing the cost of lithography. Not only that, but it is also possible to minimize the adverse effects of heat on the mask 300.

Above, the present invention has been described in detail using preferred embodiments, but the scope of the present invention is not limited to the specific embodiments and should be interpreted in accordance with the appended claims. Additionally, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

100: Chamber
200: Light source unit
300: mask
400: Optical system
500: wafer stage
600: Barrier module

Claims (8)

In the barrier module for blocking the inflow of foreign substances into the mask disposed at the top inside the chamber of the lithography apparatus,
The barrier module emits an electron beam into the lower area of the mask to form an electrical potential barrier,
An electrical potential barrier module with a heat transfer prevention function configured to prevent heat generated from the barrier module from being transferred to the mask.
In claim 1,
A filament that generates an electron beam;
a housing formed to accommodate the filament inside, and having a slit formed in the longitudinal direction to emit the electron beam in a direction parallel to the bottom of the mask; and
Cooling means for cooling the housing;
An electrical potential barrier module with a heat transfer prevention function, comprising:
In claim 2,
An electrical potential barrier module with a heat transfer prevention function, characterized in that a guide part is formed in the housing to guide the direction of light generated from the filament in a preset direction.
In claim 3,
The guide portion is formed to protrude in an area around the slit of the housing, and the amount of protrusion of the guide portion is determined based on at least one of the relative position between the barrier module and the mask and the size of the mask. Equipped with an electrical potential barrier module.
A chamber whose interior is maintained in a vacuum state;
a light source unit disposed within the chamber and generating light for lithography;
a mask disposed at the top of the chamber;
An optical system that transmits the light generated by the light source unit to the mask; and
a barrier module that emits an electron beam into a lower area of the mask to form an electrical potential barrier to block particles from entering the mask;
Including,
A lithographic apparatus configured to prevent heat generated from the barrier module from being transferred to the mask.
The method of claim 5, wherein the barrier module,
A filament that generates an electron beam;
a housing formed to accommodate the filament inside, and having a slit formed in the longitudinal direction to emit the electron beam in a direction parallel to the bottom of the mask; and
Cooling means for cooling the housing;
A lithographic apparatus comprising:
In claim 6,
A lithographic apparatus, characterized in that a guide part is formed in the housing to guide the direction of light generated from the filament in a preset direction.
In claim 7,
The guide portion is formed to protrude in an area around the slit of the housing, and the amount of protrusion of the guide portion is determined based on at least one of a relative position between the barrier module and the mask and a size of the mask.

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