JPH02218113A - Method of replication pattern and mask - Google Patents

Abstract

PURPOSE:To obviate a mechanical diaphragm mechanism by placing a plate-like energy ray block mask on the side on which energy ray for a mask for replicating patterns area incident or on the side opposite to the above side and performing pattern replicating. CONSTITUTION:A light-shielding mask 18 is rectangular in the same as a photomask 10. In the center, a light-transmitting hole 18A of a shape analogues to the dodecagonal plan figure surrounded by the inside edge of the light- shielding area 14 of the photomask 10. A light-shielding mask 19 is placed between a condenser lens 24 and the photomask 10 without using an diaphragm mechanism 26. In exposure process, the relative placement relationship of both masks 10 and 18 is determined so that light that passes through a pattern area 12 to be exposed of the photomask 10 enters the light-transmission hole 18A of the light-shielding mask 18 and light that passes through the mask substrate portion in the periphery of the light-shielding area 14 is blocked by the light- shielding mask 18. Thus, pattern replication can be performed efficiency without using a mechanical diaphragm mechanism.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of transferring a pattern such as an integrated circuit pattern to a resist layer on a wafer using energy beams such as light, X-rays, and electron beams, and a method of transferring a pattern such as an integrated circuit pattern to a resist layer on a wafer. This relates to an energy ray blocking mask that is used directly in practice.

[Summary of the Invention] The present invention provides a method for transferring a pattern at the inner edge of the energy ray blocking region when performing pattern transfer using a transfer mask in which an energy ray blocking region is formed in a belt shape so as to surround a pattern region to be transferred. By arranging a plate-shaped energy ray blocking mask having an energy ray transmitting part with a similar shape to the enclosed planar figure on the energy ray incident side of the transfer mask or on the opposite side thereof, it is possible to efficiently achieve this without using a mechanical aperture mechanism. It is designed to allow pattern transfer.

[Prior Art] Conventionally, in a pattern transfer apparatus such as a step-and-repeat type reduction projection exposure apparatus, a photomask lO as illustrated in FIG. 23 has been used.

In the photomask IO, an exposed pattern region 12 is formed on the surface of a rectangular mask substrate made of glass or quartz, for example, by depositing and patterning a metal such as chromium.

The pattern area 12 to be exposed is formed by arranging, for example, eight in-chip pattern areas A to H in an orthogonal matrix, and the planar figure of the area 12 corresponding to the outline of this arrangement forms a rectangle. ing. The rectangular region 12 is arranged so that its four sides are parallel to the four sides of the photomask IO.

A band-shaped light-shielding region 14 is formed in the photomask IO so as to surround the rectangular region 12 . This light shielding area 14 is an area onto which the aperture end blur of the diaphragm mechanism is projected, as will be described later.

FIG. 24 shows an example of a projection exposure system using the photomask IO as described above. Light emitted from the illumination system including the lamp 20 and the mirror 22 is transmitted through the condenser lens 24, the aperture mechanism 26, and the photomask lO1 projection lens (
For example, the wafer 30 on the wafer stage is irradiated via a 5:1 reduction projection lens) 28. The wafer stage is
The wafer position can be arbitrarily controlled in the X direction (left-right direction), the Y direction (front-back direction), the Z direction (vertical direction, that is, the optical axis direction), and the θ direction (rotational direction).

The aperture mechanism 26 includes two light shielding members P and Q that are movable in the X direction, as shown in the planar arrangement in FIG.

A rectangular aperture hole 26a is formed by combining two light shielding members R and S that are movable in the Y direction.
The position of each light shielding member can be controlled such that the opening end blur of 8a is projected onto the light shielding area 14 on the photomask 10.

In the exposure process, after setting the photomask 10 on the mask stage, mask positioning is performed by controlling the position of the mask stage in the X, Y, and θ directions, and after adjusting the aperture, the wafer is set on the wafer stage. The wafer is aligned by controlling the position of the wafer stage in the X, Y, Z, and θ directions. After this, a shutter (not shown) is opened to perform the first exposure. When the exposure is finished, the wafer stage is moved step by step. A second exposure is performed, and the step movement and exposure are repeated in the same manner until the entire wafer is covered. Normally, such a series of operations is automatically performed under computer control.

FIG. 25 shows an example in which the pattern of the exposed pattern area 12 of the photomask IO is repeatedly transferred to the resist layer on the semiconductor wafer 30 by the above-described exposure process, and 12A shows one exposure process. The pattern transfer area is shown. Such a pattern transfer area 12A comes to be two-dimensionally arranged on the upper surface of the wafer as step movement and exposure are repeated.

[Problems to be Solved by the Invention] According to the above-mentioned prior art, the mechanical aperture mechanism 2B
Because of the use of , there were the following problems.

(a) It is necessary to drive and control the light shielding member P-S, which not only takes time, but also causes dust generated from the drive mechanism to contaminate the surface of the photomask, resulting in poor transfer.

(o) When the pattern area 12 to be exposed becomes a polygon other than a rectangle, a large number of light shielding members are required to define the aperture hole formation to fit the polygonal area, and the drive mechanism becomes even more complicated. do.

(C) When the exposed pattern area 12 becomes a polygon other than a rectangle, instead of increasing the number of light shielding members as in (Q) above, the light shielding region 14 may be formed over a wide area on the mask substrate 10A. Although this is conceivable, if this is done, the installation space for alignment marks, a frame with a dustproof pellicle, etc. on the photomask 10 will be reduced.

An object of the present invention is to enable pattern transfer without using a mechanical aperture mechanism.

[Means for Solving the Problems] The present invention forms a pattern area to be transferred on a mask substrate, and also forms a transmission blocking area in a band shape surrounding the pattern area to block transmission of energy beams for transfer. In a pattern transfer method, the method includes irradiating the energy beam onto a mask formed on a mask, and transferring a pattern image of the pattern area to be transferred onto a resist layer on a wafer using the energy beam transmitted through the mask. of (A
) or (B), the pattern is transferred as shown in FIG.

(^) A plate-shaped energy ray blocking mask having an energy ray transmitting portion having a shape similar to the planar figure surrounded by the inner edge of the transmission blocking region is disposed on the energy ray incident side of the mask, and The relative arrangement of both masks is determined so that the energy rays that have passed through the energy ray transmitting section are incident on the transferred pattern region, and the blurred edges of the energy ray transmitting section are projected into the transmission blocking region. Pattern transfer is performed in this state.

(B) A plate-shaped energy ray blocking mask having an energy ray transmitting portion having a shape similar to the planar figure surrounded by the inner edge of the transmission blocking region is provided on the side opposite to the energy ray incident side of the mask. so that the energy rays that have passed through the transferred pattern area are incident on the energy ray transmitting section, and the energy rays that have passed through the mask substrate portion around the transmission blocking area are blocked by the energy ray blocking mask. Pattern transfer is performed with the relative arrangement of both masks determined.

[Function] According to the pattern transfer method of the present invention, a plate-shaped energy ray blocking mask is placed on the energy ray incident side of the pattern transfer mask or on the opposite side to perform pattern transfer, so no mechanical aperture mechanism is required. As mentioned above (
Problems such as (a) to (c) can be solved.

[Example] FIG. 1 shows a photomask lO used for carrying out the present invention. This photomask differs from the one in FIG. 23 in that the shapes of the exposed pattern area 12 and the light-shielding area 14 have been changed. It is.

In the exposed pattern area 12, 12 in-chip pattern areas A-L, each having a rectangular shape and approximately the same size, are arranged in an orthogonal matrix, and the area corresponds to the outline of this orthogonal matrix arrangement. The 12 plane figures form a dodecagon that can be divided into two equal parts in each direction in the row and column directions, and the partial figures on both sides of each bisector are symmetrical with respect to the bisector. There is. Such a dodecagonal area 1
A band-shaped light-shielding region 14 of a constant width is formed to surround 2, and the contour shape of this light-shielding region 14 forms a dodecagon that is similar to the planar shape of the region 12.

According to the in-chip pattern area arrangement as shown in FIG. 1, there are 23
More in-chip pattern areas can be arranged than in the case shown in the figure. Note that the effective exposure area 18 is determined by the lens diameter of the projection exposure system, etc.

FIG. 2 shows a plate-shaped light shielding mask 18 used in combination with the photomask 10 of FIG. 1.

The light-shielding mask 18 has a rectangular shape like the photomask IO, and the light-shielding area 14 of the photomask 10 is located in the center.
A light transmitting hole 18A having a shape similar to a dodecagonal planar figure surrounded by the inner edge of the light transmitting hole 18A is provided.

The portion of the light-shielding mask 18 other than the light-transmitting hole 18A may be made of a light-shielding material itself, or may be constructed by coating a light-shielding substance on the surface of a light-transmitting material.

FIG. 3 shows a projection exposure system according to a first embodiment of the present invention. This projection exposure system differs from the one shown in FIG. 24 in that, first, an aperture mechanism 26 is not used. Second, the light-shielding mask 18 shown in FIG. 2 is placed between the condenser lens 24 and the photomask lO shown in FIG.
Other points are the same as those described in FIG. 24.

During the exposure process, the light transmission holes 18 of the light-shielding mask 18 are
The light transmitted through A enters the exposed pattern area 12 of the photomask IO, and the edge blur 18a' of the edge 18a of the light transmission hole 18A is projected into the light-shielding area 14 as shown in FIG. Pattern transfer is performed after determining the relative arrangement of both masks 10 and 18.

FIG. 4 shows a projection exposure system according to a second embodiment of the present invention. This projection exposure system differs from the one shown in FIG. The light-shielding mask 18 shown in FIG. 2 is placed in the area.

During the exposure process, the light transmitted through the exposed pattern area 12 of the photomask 10 passes through the light transmission hole 1 of the light-shielding mask 18.
Both masks 10 . ．． Pattern transfer is performed after determining the relative arrangement of 1B.

FIG. 5 shows an example of pattern transfer to the resist layer on the semiconductor wafer 30 as described above, and 12A indicates a pattern transfer area transferred in one exposure. Comparing FIG. 5 and FIG. 25, the number of patterns in the chip transferred per exposure is larger in the case of FIG.
It is clear that the number of pattern transfers per wafer can be reduced.

FIG. 6 shows a dodecagonal planar figure of the exposed pattern area 12, where the lengths of the three sides along the X direction (row direction) are a, 2a, and a, and the lengths of the three sides along the X direction (column direction) are a, 2a, and a. Assuming that the lengths of the three sides are 2b and 2b, such a figure is constructed by arranging the pattern areas within the chip as shown in FIGS. 7 to 9. That is, in the example shown in FIG. 7, 12 rectangular in-chip pattern areas B1 whose short and long sides have lengths a and b, respectively, are arranged in an orthogonal matrix. In the example shown in FIG. 8, 24 rectangular in-chip pattern regions B2 having short and long sides of length b/2 and a, respectively, are arranged in an orthogonal matrix. Furthermore, in the example shown in FIG. 9, 48 rectangular in-chip pattern areas B3 having short and long sides of length a/2 and b/2, respectively, are arranged in an orthogonal matrix.

FIG. 1O shows a combined arrangement when the figures of FIG. 6 are transferred by a step-and-repeat method, and are closely arranged in both the X direction and the X direction.

11, 13, 15, 17, 19, and 21 all show other examples of the planar figures of the exposed pattern area 12, and these planar figures are also Several examples of arrangement can be easily considered for each figure by analogy with FIGS. 7 to 9.

In the dodecagonal planar figure in Figure 11, the lengths of all three sides in the X direction are a, and the lengths of all three sides in the X direction are b.
As shown in FIG. 12, a close combination arrangement is possible.

The dodecagonal planar figure in FIG. 13 has three sides in the X direction with a length a, and three sides in the X direction with lengths b, 2b,
b, it is possible to arrange them in close combination as shown in FIG.

The dodecagonal planar figure in FIG. 15 has the length of three sides in the X direction as a, and the lengths of the three sides in the X direction as b, 3b,
b, it is possible to arrange them in close combination as shown in FIG.

The dodecagonal planar figure in FIG. 17 has the length of three sides in the X direction as a, and the lengths of the three sides in the X direction as b, 4b,
b, it is possible to arrange them in close combination as shown in FIG.

The 20-sided planar figure in Fig. 19 has the lengths of the five sides in the X direction as a, a, 2a, a, a, and the lengths of the five sides in the X direction as b, 2b, b, b. As a result, a close combination arrangement as shown in FIG. 20 is possible.

The 28-sided planar figure in FIG. 21 has the lengths of the seven sides in the X direction as a, a, a, 2a, a, a, a, and the lengths of the seven sides in the X direction as b, b, 2b, b, b, b,
A close interlocking arrangement as shown in FIG. 22 is possible.

For a photomask having an exposed pattern area 12 as shown in FIG. 6, FIG. 11, FIG. 13, FIG. 15, FIG. 17, FIG. 18, or FIG. It can be produced in the same manner as described in FIG. 2, and exposed in the same manner as described in FIG. 3 or 4.

[Effects of the Invention] As described in 1 below, according to the present invention, by using a plate-shaped energy ray blocking mask such as the light blocking mask 1B, nog-turn transfer can be performed without using a mechanical aperture mechanism. By doing so, the following effects can be obtained.

(a) Since there is no need to control the drive of the light shielding member, the pattern can be transferred efficiently and the occurrence of transfer defects due to dust generation can be prevented. The energy ray blocking mask may be arranged at a predetermined position on the fixed stage, and in this way, positioning control of the energy ray blocking mask can also be omitted.

(o) Transferred pattern area (exposed pattern area 12)
Even if it becomes a polygon other than a rectangle, an energy ray blocking mask that is suitable for it can be easily created, and there is no need to add a light shielding member like in the past.Also, it is a transfer mask that has a pattern area to be transferred. Also, it is not necessary to form the energy ray blocking region (light shielding region 14) over a particularly large area.

Great flexibility in placement of alignment marks, frames with pellicles, etc.

(c) By making the pattern area to be transferred polygonal, more pattern areas within the chip can be arranged, thereby improving throughput.

[Brief explanation of the drawing]

1 and MS2 are top views respectively showing a photomask and a light-shielding mask used in carrying out the present invention, and FIGS. 3 and 4 show projection exposure systems according to the first and second embodiments of the present invention, respectively. 5 is a top view of a wafer showing an example of transfer of the mask pattern of FIG. 1, FIG. 6 is a diagram showing an example of a planar figure of the exposed pattern area, and FIGS. FIG. 4 is a plan view showing different examples of arrangement of intra-chip pattern desired areas within the exposed pattern region. FIG. 10 is a plan view showing the combined arrangement of the figures in FIG. 6, and FIGS. 11, 13, 15, 17, 18, and 21 are plan views of the exposed pattern area. Figures 12, 14, 16, 18, 20, and 22 are Figures 11, 13, 15, and 17, respectively, showing other examples. , FIG. 23 is a top view showing the arrangement of light shielding members above a photomask according to a conventional example, and FIG. 24 is a diagram showing an example of a projection exposure system. , Figure 25 is
24 is a top view of a wafer showing an example of transferring the mask pattern of FIG. 23; FIG. lO... Photomask, 12... Exposed pattern area, 14... Light blocking area, 18... Light blocking mask, 20...
··lamp. 22... Mirror, 24... Condenser lens, 2nd... Projection lens, 30... Wafer, ANL, Bl
~B3... In-chip pattern area.

Claims (1)

[Claims] 1. A pattern region to be transferred is formed on a mask substrate, and a transmission blocking region for blocking transmission of energy rays for transfer is formed in a band shape to surround the pattern region to be transferred. A pattern transfer method comprising irradiating a mask with the energy rays and transferring a pattern image of the pattern area to be transferred to a resist layer on a wafer by the energy rays transmitted through the mask, the energy rays being incident on the mask. A plate-shaped energy ray blocking mask having an energy ray transmitting portion having a shape similar to the planar figure surrounded by the inner edge of the transmission blocking region is disposed on the side, and the energy rays transmitted through the energy ray transmitting portion are disposed on the side. The pattern transfer is performed in a state in which the relative arrangement of both masks is determined such that the energy beam is incident on the pattern area to be transferred and the edge blur of the energy beam transmitting part is projected into the transmission blocking area. A pattern transfer method. 2. The above-mentioned energy is applied to a mask formed by forming a transfer pattern area on a mask substrate and forming a band-shaped transmission blocking area surrounding the transfer pattern area to block transmission of energy beams for transfer. In a pattern transfer method that includes irradiating a beam and transferring a pattern image of the pattern area to be transferred onto a resist layer on a wafer by energy beams transmitted through the mask, on a side of the mask opposite to an incident side of the energy beams. A plate-shaped energy ray blocking mask having an energy ray transmitting portion having a shape similar to a planar figure surrounded by an inner edge of the transmission blocking region is disposed, and the energy rays transmitted through the transferred pattern region are transmitted to the transfer pattern region. Pattern transfer is performed with the relative arrangement of both masks determined such that the energy rays that are incident on the energy ray transmitting section and transmitted through the mask substrate portion around the transmission blocking region are blocked by the energy ray blocking mask. A pattern transfer method characterized by performing the following. 3. The above-mentioned energy is applied to a mask formed by forming a transfer pattern area on a mask substrate and forming a band-shaped transmission blocking area surrounding the transfer pattern area to block transmission of transfer energy rays. A plate-shaped energy ray blocking mask to be placed on the energy ray incident side of the mask or on the opposite side when the pattern image of the transferred pattern area is transferred to the resist layer on the wafer by irradiating the radiation. An energy ray blocking mask characterized by having an energy ray transmitting portion having a shape similar to a planar figure surrounded by an inner edge of the transmission blocking region.