JPH0670963B2 - Pattern transfer method and mask - Google Patents

Description

The present invention relates to a method for transferring a pattern such as an integrated circuit pattern to a resist layer on a wafer by energy rays such as light, X-rays, electron beams, and the like. The present invention relates to a pattern transfer mask used directly for implementation.

SUMMARY OF THE INVENTION According to the present invention, in a pattern transfer mask, a transferred pattern area is formed in a polygonal shape of a dodecagon or more, and a rectangular contour shape is formed so as to surround the polygonal transferred pattern area. By forming the transmission blocking region, the throughput is improved.

[Prior Art] Conventionally, in a pattern transfer apparatus such as a step-and-repeat type reduced projection exposure apparatus, a photomask 10 as illustrated in FIG. 20 is used.

In the photomask 10, an exposed pattern region 12 is formed by depositing and patterning a metal such as chromium on the surface of a rectangular mask substrate made of, for example, glass or quartz.

The exposed pattern area 12 is formed by arranging eight in-chip pattern areas A to H in an orthogonal matrix as an example, and the plane figure of the area 12 corresponding to the contour of this arrangement is rectangular. There is. The rectangular region 12 is arranged so that its four sides are parallel to the four sides of the photomask 10.

A band-shaped light-shielding region 14 is formed on the photomask 10 so as to surround the rectangular region 12. This shaded area 14 is
As will be described later, this is a region where the aperture end blur of the diaphragm mechanism is projected.

FIG. 21 shows an example of a projection exposure system using the photomask 10 as described above. The light emitted from the illumination system including the lamp 20 and the mirror 22 is transmitted to the wafer 30 on the wafer stage via the condenser lens 24, the diaphragm mechanism 26, the photomask 10, and the projection lens (for example, 5: 1 reduction projection lens) 28. Is irradiated. The wafer stage is in the X direction (left and right direction),
Y direction (front-back direction), Z direction (vertical direction, that is, optical axis direction)
And the wafer position can be arbitrarily controlled in the θ direction (rotation direction).

The diaphragm mechanism 26 is a combination of two light blocking members P and Q that can move in the X direction and two light blocking members R and S that can move in the Y direction as shown in the plan view of FIG. A shaped aperture hole 26a is formed, and the position of each light shielding member can be controlled so that the open end blur of the aperture hole 26a is projected on the light shielding region 14 on the photomask 10.

In the exposure process, after the photomask 10 is set on the mask stage, the mask is aligned by controlling the position of the mask stage in the X, Y, and θ directions. Then, after adjusting the diaphragm, the wafer is set on the wafer stage, and the wafer is aligned by controlling the position of the wafer stage in the X, Y, Z, and θ directions. After that, a shutter (not shown) is opened to perform the first exposure, and when the exposure is finished, the wafer stage is moved stepwise to perform the second exposure,
Similarly, step movement and exposure are repeated until the entire surface of the wafer is completed. Usually, such a series of operations is automatically performed under computer control.

FIG. 22 shows a semiconductor wafer 30 which has been processed by the exposure process as described above.
It shows an example in which the pattern of the exposed pattern region 12 of the photomask 10 is repeatedly transferred to the upper resist layer,
12A indicates a pattern transfer area transferred by one exposure. Such pattern transfer areas 12A are two-dimensionally arranged on the upper surface of the wafer as the step movement and the exposure are repeated.

[Problems to be Solved by the Invention] According to the above-mentioned conventional technique, when a circular effective exposure area 16 determined by the lens diameter of the projection exposure system is given, a rectangle which is almost inscribed in the circle of this area 16 is covered. Exposure pattern area
The in-chip pattern corresponding to 12 and arranged in the rectangular region 12 is transferred onto the wafer by one exposure process.

To improve throughput, a rectangular area 12
The area of the circular effective exposure area 16 must be large enough to circumscribe the rectangle of the area 12. Therefore, as the exposure apparatus, one with a large lens diameter is required, and
Also in the mask substrate, there is a problem that the installation space for the alignment mark, the frame with the pellicle for dust prevention, etc. is reduced.

An object of the present invention is to improve throughput without requiring expansion of the effective exposure area.

[Means for Solving the Problems] The present invention relates to a mask formed by forming a pattern area to be transferred on a mask substrate through a rectangular aperture hole with a variable aperture size provided in an aperture mechanism. A pattern transfer method comprising irradiating an energy beam of, and transferring the pattern image of the transferred pattern region to a resist layer on a wafer by the energy beam transmitted through the mask,
The transferred pattern area is formed by arranging a plurality of in-chip pattern areas each having a rectangular shape and substantially the same size in an orthogonal matrix, and a plane figure of the transferred pattern area corresponding to the contour of the orthogonal matrix arrangement. Is a polygon that can be bisected in each direction in the row direction and the column direction, and the subfigures on both sides of each bisector are symmetrical with respect to the bisector. And on the mask substrate,
A material that blocks the transmission of the energy rays is applied so as to surround the transferred pattern area to form a transmission blocking area having a rectangular contour shape. The pattern transfer is performed in a state in which it is determined that the opening edge blur of the is projected in the transmission blocking area.

[Operation] According to the pattern transfer method of the present invention, since the transferred pattern area has a polygonal shape as illustrated as the exposed pattern area 12 in FIG. 1, the transferred area can be transferred without expanding the effective exposed area 18. More pattern areas in the chip can be arranged in the pattern area.

Further, since the pattern transfer is performed by setting the opening size of the rectangular stop hole so as to match the rectangular contour-shaped transmission blocking area formed around the transferred pattern area. Even if the shape is polygonal, the pattern can be transferred without any problem with the conventional diaphragm mechanism.

[Embodiment] FIG. 1 shows an arrangement of a light shielding member above a photomask according to an embodiment of the present invention. The difference from FIG. 20 is that the exposed pattern area 12 and the light shielding area 14 in the photomask 10 are different from each other. The shape has been changed, and the other points are
Similar to that described above with respect to FIGS. 20 and 21.

In the exposed pattern area 12, twelve in-chip pattern areas A to L each having a rectangular shape and substantially the same size are arranged in an orthogonal matrix, and an area corresponding to the contour of this orthogonal matrix arrangement. The twelve plane figures can be bisected in each direction in the row direction and the column direction, and the subfigures on both sides of each bisector form a dodecagon that is symmetrical with respect to the bisector. There is. A light shielding region 14 having a rectangular contour shape is formed so as to surround such a dodecagonal region 12.

In the exposure process, the arrangement of the exposure members P to S is adjusted so that the aperture size of the aperture hole 26a (FIG. 21) is determined so that the aperture edge blur of the aperture hole 26a is projected in the light shielding region 14. Pattern transfer with.

FIG. 2 shows an example in which the pattern is transferred to the resist layer on the semiconductor wafer 30 in this way, and 12A indicates a pattern transfer region transferred by one exposure. Second
Comparing FIG. 22 with FIG. 22, 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 sheet is small.

FIG. 3 shows a dodecagonal plane figure of the exposed pattern area 12, in which the lengths of the three sides along the x direction (row direction) are a,
2a, a, and the length of three sides along the y direction (column direction) is b,
2b and 2b, such a figure is formed by arranging in-chip pattern areas as shown in FIGS. 4 to 6. That is, in the example of FIG. 4, twelve rectangular in-chip pattern regions B ₁ having short sides and long sides of lengths a and b are arranged in an orthogonal matrix. Also, in the example of FIG. 5, the rectangular in-chip pattern area B whose short and long sides are b / 2 and a, respectively.
₂ is obtained by arranged 24 orthogonal matrix manner. Further, in the example of FIG. 6, the lengths of the short side and the long side are a / 2 and b, respectively.
Forty-eight rectangular in-chip pattern areas B ₃ of / 2 are arranged in an orthogonal matrix.

FIG. 7 shows a combination arrangement when the figure of FIG. 3 is transferred by the step-and-repeat method, and the arrangement is close in both the x direction and the y direction.

FIG. 8, FIG. 10, FIG. 12, FIG. 14, FIG. 16 and FIG. 18 all show other examples of the plane figure of the exposed pattern area 12, and these plane figures are also shown. By analogy with FIGS. 4 to 6, some arrangement examples can be easily considered for each figure.

The dodecagonal plane figure in FIG. 8 has three sides in the x direction each having a length of a and three sides in the y direction each having b, and as shown in FIG. It is possible to perform the combined arrangement described above.

In the dodecagonal plane figure of FIG. 10, the lengths of the three sides in the x direction are all a and the lengths of the three sides in the y direction are b, 2b, and b, as shown in FIG. It is possible to arrange a combination close to.

In the dodecagonal plane figure of FIG. 12, the lengths of the three sides in the x direction are all a, and the lengths of the three sides in the y direction are b, 3b, and b, as shown in FIG. It is possible to arrange a combination close to.

In the dodecagonal plane figure of FIG. 14, the lengths of the three sides in the x direction are all a, and the lengths of the three sides in the y direction are b, 4b, and b, as shown in FIG. It is possible to arrange a combination close to.

The 20-sided plane figure of FIG. 16 has five sides in the x direction with lengths a, a, 2a, a, a and five sides in the y direction with length b.
b, 2b, b, b, it is possible to make a close combination arrangement as shown in FIG.

In the 28-sided plane figure of FIG. 18, the length of 7 sides in the x direction is a, a, a, 2a, a, a, a, and the length of 5 sides in the y direction is b, b, b, 2b, b, b, b, a close combination arrangement is possible as shown in FIG.

The exposed pattern area 12 as shown in FIG. 3, FIG. 8, FIG. 10, FIG. 12, FIG. 14, FIG. 14, FIG. 16 or FIG. An exposure process can be performed in the same manner as described with reference to FIG. 1 by forming a light shielding region having a rectangular contour shape.

[Effects of the Invention] As described above, according to the present invention, since the transferred pattern area is formed in a polygonal shape and more pattern areas in the chip are arranged, the transfer area per exposure is increased, The effect of improving the throughput can be obtained.

Further, since the effective exposure area does not have to be enlarged, there is an advantage that a large-diameter exposure apparatus need not be used, and that a mask substrate can have a sufficient installation space for alignment marks, a frame with a pellicle, and the like.

In addition, since the transmission blocking area having a rectangular contour is provided around the transferred pattern area, there is an advantage that the pattern transfer can be performed with the conventional diaphragm mechanism.

[Brief description of drawings]

FIG. 1 is a top view showing a light shielding member arrangement above a photomask according to an embodiment of the present invention, FIG. 2 is a wafer top view showing an example of transferring the mask pattern of FIG. 1, and FIG. FIGS. 4 to 6 are plan views showing examples of different arrangements of in-chip pattern regions in the exposed pattern region, and FIG. 7 is a diagram of FIG. And FIG. 8, FIG. 10, FIG. 12, FIG. 14, FIG. 16 and FIG. 18 are views showing other examples of the plane figure of the exposed pattern area, respectively. Figure 9, Figure 11, Figure 13, Figure 15, Figure 17, and Figure 19 are the figures in Figure 8, Figure 10, Figure 12, Figure 14, Figure 14, Figure 16, and Figure 18, respectively. Fig. 20 is a plan view showing a combination arrangement of Fig. 20, Fig. 20 is a top view showing the arrangement of a light shielding member above a photomask according to a conventional example, and Fig. 21 is a projection exposure system. Shows an example, FIG. 22 is a wafer top view showing a transfer example of a mask pattern of Figure 20. 10 …… Photomask, 12 …… Exposed pattern area, 14 ……
Light-blocking area, 20 ... Lamp, 22 ... Mirror, 24 ... Condenser lens, 26 ... Aperture mechanism, 28 ... Projection lens, 30 ...
... Wafer, P to S ... Light-shielding member, A to L, B _{1 to} B ₃ ... Pattern area in chip.

Claims (2)

[Claims] 1. A transfer energy beam is applied to a mask formed by forming a pattern area to be transferred on a mask substrate through a rectangular aperture hole with a variable aperture size provided in an aperture mechanism, In a pattern transfer method including transferring a pattern image of the transferred pattern area to a resist layer on a wafer by an energy ray transmitted through a mask, the transferred pattern area has a plurality of chips each having a rectangular shape and substantially the same size. An inner pattern area is arranged in an orthogonal matrix, and the plane figure of the transferred pattern area corresponding to the contour of the orthogonal matrix arrangement can be equally divided into two in the row direction and the column direction. Further, for each bisector, the partial figures on both sides of the bisector form a polygon of a dodecagon or more, which is symmetrical with respect to the bisector, and the energy is provided on the mask substrate. A material that blocks the transmission of light to surround the transferred pattern area to form a transmission blocking area having a rectangular contour shape, and the aperture size of the aperture is defined by the opening size of the aperture. A pattern transfer method, wherein pattern transfer is performed in a state where a blur is projected in the transmission blocking area. 2. A pattern transfer mask formed by forming a transferred pattern area on a mask substrate, wherein the transferred pattern area has a plurality of in-chip pattern areas each having a rectangular shape and substantially the same size in an orthogonal matrix. The plane figure of the transferred pattern area corresponding to the contour of the orthogonal matrix arrangement can be bisected in each direction in the row direction and the column direction and for each bisector line. The partial figures on both sides thereof form a polygon of 12 or more sides that are symmetrical with respect to the bisector, and a material for blocking transmission of the energy rays is provided on the mask substrate in the transferred pattern area. A pattern transfer mask, characterized in that a transmission blocking region having a rectangular outline shape is formed so as to surround it.