JP2947133B2 - X-ray mask structure and X-ray exposure method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure and an exposure method of an X-ray mask, and more particularly to a method of suppressing a pressure fluctuation near a membrane during X-ray exposure and controlling a flow of gas during step movement to deform the membrane. The present invention relates to a structure of an X-ray mask and an exposure method characterized by suppressing the above.

[0002]

2. Description of the Related Art In the conventional X-ray equal-size exposure, an X-ray mask and a wafer coated with a resist are exposed at an interval of several tens of μm. In this case, when stepping to the next exposure position with a narrow gap (interval) of several tens μm, X
Because there is a high risk of damaging the line mask, X
Move after evacuating the line mask. After the movement is completed, the gap (interval) between the X-ray mask and the wafer is returned to a narrow gap of several tens of μm for exposure.

[0003]

However, when the X-ray mask is step-moved for each exposure, the membrane is deformed due to the viscosity of the gas.

For example, if the X-ray mask is moved downward with respect to the wafer 4 with the narrow gap as shown in FIG. 4 without evacuating the X-ray mask, the upper portion of the membrane 1 is deformed toward the wafer. . The amount of deformation of the membrane 1 is represented by X
It increases as the relative movement speed of the line mask increases and the gap between the line mask and the wafer decreases.

The X-ray mask is composed of a membrane support 7, a membrane 1, and a pattern formed by an X-ray absorber (not shown) such as tungsten, tantalum, or gold provided on the membrane. The membrane 1 is an X-ray transparent material thin film, for example, a Si nitride film, a SiC film, a BN film.
/ Polyimide composite film or the like.

As shown in FIG. 4, when the membrane 1 is deformed, it comes into contact with the wafer 4 and may damage the X-ray mask. Therefore, it is necessary to evacuate the X-ray mask during the step movement.

However, even when the X-ray mask is retracted and moved, as shown in FIG. 5, when the gap between the X-ray mask and the wafer is narrowed (when it is moved in the direction of arrow 5),
The membrane 1 expands outward with respect to the wafer 4 (the side opposite to the wafer 4).

As described above, when exposure is performed in a state where the membrane is deformed, the transfer accuracy is reduced (in the 1 × transfer method, the dimensional accuracy and the position accuracy of the pattern of the X-ray mask are the device accuracy as they are). A waiting time of several seconds is required for the membrane to return to the plane, causing a decrease in throughput.

Conventionally, in order to shorten the relaxation time until the deformation of the membrane returns to its original state, (1) thickening the membrane thickness, (2) strengthening the tensile stress of the membrane, (3)
Measures such as processing the periphery of the membrane into a mesa shape have been considered, but none of them has been a fundamental solution.

Accordingly, an object of the present invention is to provide an X-ray mask and an X-ray exposure method for suppressing the deformation of a membrane by controlling the flow of gas in the vicinity of the membrane in order to solve these problems. I do.

[0011]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a membrane support, a membrane, and an X.
An X-ray mask composed of a pattern formed by a line absorber, comprising pores for controlling a flow of gas between the membrane support and a frame , wherein an opening end of the pores is provided.
In addition, the present invention provides an X-ray mask structure in which the frame has a projection shape .

Further, the present invention comprises a pattern comprising a membrane support, a membrane and an X-ray absorber ,
Gas flow between the membrane support and the frame
X-ray exposure using X-ray mask with pores for controlling
An optical method , wherein an X-ray exposure method is provided for controlling a flow of gas near the membrane so as to suppress deformation of the membrane.

That is, in the exposure method of the present invention,
When step-moving while maintaining the interval between the X-ray mask and the wafer, the gas is supplied from one side of the pores facing each other, and the gas is exhausted from the other side of the pores,
A gas flow is created in the same direction as the moving direction of the X-ray mask.

In the exposure method of the present invention, when the distance between the X-ray mask and the wafer is reduced, gas is exhausted from the pores so that the pressure around the membrane is kept constant. Controlled. Then, when widening the distance between the X-ray mask and the wafer, gas is supplied from the pores to keep the pressure around the membrane constant.

[0015]

The principle and operation of the present invention will be described below.

As shown in FIG. 1, in the present invention, pores 2 for pressure adjustment are provided in the vicinity of a membrane 1 to control the pressure when the gap between the X-ray mask and the wafer is changed, and to reduce the air flow during the step movement. By making it, the deformation of the membrane 1 is suppressed.

In the present invention, when changing the gap between the X-ray mask and the wafer,
When the line mask or the wafer is moved, the deformation of the membrane 1 is suppressed.

Therefore, according to the present invention, the X-ray mask does not need to be evacuated during the step movement or can be made very small.

Further, according to the present invention, even when setting the gap between the X-ray mask and the wafer, it is not necessary to secure a relaxation time until the deformation of the membrane converges, thereby greatly improving the throughput. You.

Further, according to the present invention, since the stress applied to the membrane is reduced, the durability of the X-ray mask is improved.

[0021]

Embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a structure of an X-ray mask capable of suppressing deformation of a membrane and an X-ray 1: 1 exposure method will be described.

FIG. 1A is a view showing an embodiment of X according to an embodiment of the present invention.
FIG. 1B is a plan view showing the configuration of the line mask, and FIG.
3A schematically illustrates a cross section taken along line AA ′ of FIG.

Referring to FIG. 1, pores 2 for pressure adjustment are provided near the membrane 1 of the X-ray mask. Further, in order to prevent gas around the membrane 1 from entering the membrane region, the frame 3 has a mesa structure outside the pores 2 (see FIG. 1B).

As described in the conventional example (see FIG. 5), when the distance between the X-ray mask and the wafer is reduced (moves in the direction of arrow 5), the gas around the membrane 1 collects at the center of the membrane 1. The membrane 1 is deformed so that its center swells outward as shown in the figure.

On the other hand, in the present embodiment, X
When the distance between the line mask and the wafer is reduced (moves in the direction of arrow 5), as shown in FIG. 3, gas 6 between the wafer 4 and the membrane 1 is exhausted from the pores 2 to keep the pressure around the membrane 1 constant. , The deformation of the membrane 1 is suppressed.

On the other hand, when the distance between the membrane 1 and the wafer 4 is widened, the gas 6 is supplied from the pores 2 to keep the pressure around the membrane 1 constant, thereby suppressing the deformation of the membrane. I have.

FIG. 4 shows a state of deformation of the membrane 1 in the conventional example when the X-ray mask and the wafer are step-moved (moved in the direction indicated by the arrow 5) while maintaining a narrow gap. The membrane 1 is deformed as shown in the figure due to the viscosity of the gas.

On the other hand, in the present embodiment, during the step movement in the narrow gap state, as shown in FIG. 2, the gas is supplied from one of the pores and exhausted from the other, so that the X-ray is emitted. A gas flow is created in the same direction as the mask movement direction (indicated by arrow 5).

When the gas flows in the moving direction of the X-ray mask in this manner, the membrane 1 is not viscous, so that the deformation of the membrane 1 is suppressed.

In the above embodiment, the flow rate of the supplied or exhausted gas is optimized according to the area of the membrane, the moving speed and the pressure of the X-ray mask.

Further, a pressure sensor may be provided near the membrane, and a change in pressure may be fed back to control the flow rate. The gas exhausted or supplied from the pores 2 is, for example, air or helium gas.

[0032]

As described above, according to the present invention,
Since the deformation of the membrane during the step movement of the X-ray mask can be suppressed, there is an effect that the throughput in X-ray exposure can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of an X-ray mask according to an embodiment of the present invention. (A) It is a top view. FIG. 2B is a diagram schematically showing a cross section taken along line AA ′ of FIG.

FIG. 2 is a diagram for explaining a state of step movement of an X-ray mask according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a state of step movement of an X-ray mask according to an embodiment of the present invention.

FIG. 4 is a diagram for explaining an example of a deformation of the membrane.

FIG. 5 is a view for explaining another example of the deformation of the membrane.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Membrane 2 Pores 3 Frame 4 Wafer 5 Moving direction of X-ray mask 6 Direction of gas flow 7 Membrane support

Claims (5)

(57) [Claims] 1. A membrane support, a membrane, and X
An X-ray mask composed of a pattern formed by a line absorber, comprising pores for controlling a flow of gas between the membrane support and a frame , wherein an opening end of the pores is provided .
An X-ray mask structure, wherein the frame has a projection shape . 2. An X-ray mask structure according to claim 1, wherein said pores are provided with openings on at least sides of the periphery of said membrane which face each other. 3. A membrane support, a membrane, and X.
The membrane comprising a pattern formed by a line absorber;
To control the flow of gas between the support and the frame
An X-ray exposure method using an X-ray mask having pores.
Te, stearyl while maintaining the spacing between the X-ray mask and the wafer
When moving up, the pores on one side facing each other
Supplying gas, exhausting the gas from the pores on the other side,
Create a gas flow in the same direction as the X-ray mask moves
An X-ray exposure method, characterized in that: 4. A membrane support, a membrane, and X
The membrane comprising a pattern formed by a line absorber;
To control the flow of gas between the support and the frame
An X-ray exposure method using an X-ray mask having pores.
Te, before the time of narrowing the distance between the X-ray mask and the wafer
Exhaust gas from the pores and reduce the pressure around the membrane.
An X-ray exposure method, characterized in that it is kept constant. 5. A membrane support, a membrane, and X
The membrane comprising a pattern formed by a line absorber;
To control the flow of gas between the support and the frame
An X-ray exposure method using an X-ray mask having pores.
Te, before the time of widening the distance between the X-ray mask and the wafer
A gas is supplied from the pores to reduce the pressure around the membrane.
An X-ray exposure method, characterized in that it is kept constant.