TWI793029B - Phase shift mask - Google Patents

Abstract

A phase shift mask including a substrate, a phase shift layer, and opaque assist patterns. The phase shift layer is disposed on the substrate and has at least one rectangular opening. The rectangular opening has corners. The opaque assist patterns are disposed on the phase shift layer and are located at the corners of the rectangular opening.

Description

phase shift mask

Embodiments of the present invention relate to a photomask, and in particular to a phase shift mask (PSM).

In semiconductor manufacturing process, lithography technology plays a pivotal role. However, in the lithography process, the resolution of the exposure is an important indicator of the lithography quality. The lithography technology using a phase shift mask (PSM) is a technology developed to obtain better resolution. However, the photoresist pattern formed by the lithography process using the phase-shift mask often suffers from corner rounding defects. Therefore, how to develop a phase shift mask that can improve corner rounding is the goal of continuous efforts.

The invention provides a phase shift mask, which can effectively improve the corner rounding of the photoresist pattern formed by the lithography process.

The invention provides a phase shift mask, which includes a base, a phase shift layer and a plurality of opaque auxiliary patterns. The phase shift layer is arranged on the base and has at least one rectangular opening. The rectangular opening has multiple corners. A plurality of opaque auxiliary patterns are disposed on the phase shift layer and located at a plurality of corners of the rectangular opening.

According to an embodiment of the present invention, in the above-mentioned phase shift mask, an opaque auxiliary pattern can be provided at each corner.

According to an embodiment of the present invention, in the phase-shift mask, the plurality of opaque auxiliary patterns can be separated from each other.

According to an embodiment of the present invention, in the phase shift mask, the material of the opaque auxiliary pattern is, for example, chromium (Cr) or chromium oxide (CrO _x ).

According to an embodiment of the present invention, in the phase shift mask, the phase shift layer may have a plurality of rectangular openings. The same opaque auxiliary pattern can be located at two adjacent corners between two adjacent rectangular openings.

According to an embodiment of the present invention, in the phase shift mask, the phase shift layer may have a plurality of rectangular openings. Two opaque auxiliary patterns separated from each other may be located at two adjacent corners between adjacent two rectangular openings.

According to an embodiment of the present invention, in the phase shift mask, the light transmittance of the phase shift layer may be 3% to 12%.

According to an embodiment of the present invention, in the phase shift mask, the material of the phase shift layer is, for example, molybdenum silicide (MoSi) or molybdenum silicon oxynitride (MoSiON).

According to an embodiment of the present invention, the phase shift mask may further include an opaque boundary pattern. The opaque boundary pattern is disposed on the phase shift layer and surrounds the plurality of rectangular openings and the plurality of opaque auxiliary patterns.

Based on the above, in the phase shift mask proposed by the present invention, a plurality of opaque The auxiliary patterns are disposed on the phase shift layer and located at corners of the rectangular opening. In this way, when the phase shift mask proposed by the present invention is used for lithography process, the intensity of light energy received by the photoresist layer can be increased, thus effectively improving the quality of the photoresist pattern formed by the lithography process. The case of corner rounding.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

10,20,30: phase shift mask

100: base

102:Phase shift layer

104, 104A, 104B, 104C: opaque auxiliary patterns

106: Opaque border pattern

C: Corner

OP: Rectangular opening

FIG. 1 is a top view of a phase-shifting mask according to some embodiments of the present invention.

Fig. 2A is a sectional view along the line I-I' in Fig. 1 .

Fig. 2B is a cross-sectional view along the line II-II' in Fig. 1 .

Fig. 2C is a cross-sectional view along the section line III-III' in Fig. 1 .

Fig. 3 is a top view of a phase shift mask according to other embodiments of the present invention.

Fig. 4 is a top view of a phase shift mask according to other embodiments of the present invention.

Embodiments are listed below and described in detail with accompanying drawings, but the provided embodiments are not intended to limit the scope of the present invention. In order to facilitate understanding, the same components will be described with the same symbols in the following description. In addition, the drawings are for illustration purposes only and are not drawn to original scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 is a top view of a phase-shifting mask according to some embodiments of the present invention. Fig. 2A is a sectional view along the line I-I' in Fig. 1 . Fig. 2B is a cross-sectional view along the line II-II' in Fig. 1 . Fig. 2C is a cross-sectional view along the section line III-III' in Fig. 1 . Fig. 3 is a top view of a phase shift mask according to other embodiments of the present invention. Fig. 4 is a top view of a phase shift mask according to other embodiments of the present invention.

Referring to FIG. 1 and FIGS. 2A to 2C , the phase shift mask 10 includes a substrate 100 , a phase shift layer 102 and a plurality of opaque auxiliary patterns 104 . In some embodiments, the substrate 100 may be a transparent substrate. In some embodiments, the material of the substrate is, for example, quartz.

The phase shift layer 102 is disposed on the substrate 100 and has at least one rectangular opening OP. The rectangular opening OP has a plurality of corners C. In this embodiment, the phase shift layer 102 may have a plurality of rectangular openings OP. However, as long as the phase shift layer 102 has at least one rectangular opening OP, it falls within the scope of the present invention. In some embodiments, the rectangular opening OP may be a rectangular opening or a square opening. In this embodiment, the rectangular opening OP is an example of a rectangular opening, but the invention is not limited thereto. In some embodiments, the light transmittance of the phase shift layer 102 may be 3% to 12%. In some embodiments, the material of the phase shift layer 102 is, for example, molybdenum silicide or molybdenum silicon oxynitride. In some embodiments, the phase difference (Δθ) between the light passing through the phase shift layer 102 and the light passing through the substrate 100 may be 180 degrees.

In some embodiments, the arrangement of the rectangular openings OP may be arranged in a matrix, but is not limited to the arrangement of the openings in FIG. 1 . In other embodiments, the arrangement of the rectangular openings OP may be the arrangement of the openings in FIG. 3 or the arrangement of the openings in FIG. 4 . In addition, as shown in FIG. 1 , FIG. 3 and FIG. 4 , in some embodiments, the sizes of the plurality of rectangular openings OP may be the same or different from each other.

Referring to FIG. 1 and FIG. 2A to FIG. 2C , a plurality of opaque auxiliary patterns 104 are disposed on the phase shift layer 102 and located at a plurality of corners C of the rectangular opening OP. In some embodiments, an opaque auxiliary pattern 104 may be disposed at each corner C. Referring to FIG. In some embodiments, the plurality of opaque auxiliary patterns 104 may be separated from each other. In some embodiments, the light transmittance of the opaque auxiliary pattern 104 may be 0%. In some embodiments, the material of the opaque auxiliary pattern 104 is, for example, chromium or chromium oxide.

In some embodiments, the same opaque auxiliary pattern 104 (eg, the opaque auxiliary pattern 104A in FIG. 1 , FIG. 3 , and FIG. 4 ) can be located between two adjacent rectangular openings OP. at corner C. That is, two adjacent corners C between adjacent two rectangular openings OP can share the same opaque auxiliary pattern 104 (eg, the opaque auxiliary pattern 104A in FIGS. 1 , 3 and 4 ). In some embodiments, two opaque auxiliary patterns 104 separated from each other (eg, opaque auxiliary patterns 104B and 104C in FIG. 4 ) may be located between two adjacent rectangular openings OP. at two adjacent corners C. In some embodiments, the same opaque auxiliary pattern 104 (eg, the opaque auxiliary pattern 104A in FIG. 4 ) can be located at two adjacent corners C between adjacent two rectangular openings OP, and Two opaque auxiliary patterns 104 separated from each other (eg, opaque auxiliary patterns 104B and 104C in FIG. 4 ) can be located at two adjacent corners between adjacent two rectangular openings OP. at C.

The phase shift mask 10 may further include an opaque boundary pattern 106 . The opaque border pattern 106 is disposed on the phase shift layer 102 and surrounds the plurality of rectangular openings OP and the plurality of opaque auxiliary patterns 104 . In some embodiments, the light transmittance of the opaque boundary pattern 106 may be 0%. The material of the opaque boundary pattern 106 is, for example, chromium or chromium oxide. In a In some embodiments, the opaque auxiliary pattern 104 and the opaque boundary pattern 106 can be derived from the same material layer. That is, the opaque auxiliary pattern 104 and the opaque boundary pattern 106 can be formed simultaneously by the same process.

Based on the above embodiments, it can be known that in the phase shift mask 10 , a plurality of opaque auxiliary patterns 104 are disposed on the phase shift layer 102 and located at the corners C of the rectangular opening OP. In this way, when the phase-shift mask 10 is used for the lithography process, the intensity of the light energy received by the photoresist layer can be increased, so the corner rounding effect of the photoresist pattern formed by the lithography process can be effectively improved. Condition.

In addition, the phase-shift mask 10 of FIG. 1, the phase-shift mask 20 of FIG. 3 and the same components in the phase-shift mask 30 of FIG. For the same or similar contents in the phase shift mask 20 and the phase shift mask 30 of FIG. 4 , reference may be made to the description of the phase shift mask 10 in the above embodiment, and no further description is given here.

In summary, in the phase-shift mask of the above-mentioned embodiment, since a plurality of opaque auxiliary patterns are arranged on the phase-shift layer and located at the corners of the rectangular opening, it is possible to effectively improve the efficiency of the lithography process. The case where the corners of the formed photoresist pattern are rounded.

Although the present invention has been disclosed above with the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention should be defined by the scope of the appended patent application.

10: Phase shift mask

100: base

102:Phase shift layer

104, 104A: Opaque auxiliary pattern

106: Opaque border pattern

C: Corner

OP: Rectangular opening

Claims (8)

A phase shift mask, comprising: a base; a phase shift layer disposed on the base and having at least one rectangular opening, wherein the rectangular opening has a plurality of corners; and a plurality of opaque auxiliary patterns disposed on the base on the phase shift layer and located at a plurality of the corners of the rectangular openings, wherein the phase shift layer has a plurality of the rectangular openings, and the same opaque auxiliary pattern is located between two adjacent two adjacent corners between the rectangular openings. The phase shift mask according to claim 1, wherein the opaque auxiliary pattern is provided at each of the corners. The phase shift mask as claimed in claim 1, wherein a plurality of said opaque auxiliary patterns are separated from each other. The phase shift mask as claimed in claim 1, wherein the material of the opaque auxiliary pattern includes chromium or chromium oxide. The phase shift mask according to claim 1, wherein the phase shift layer has a plurality of rectangular openings, and the two opaque auxiliary patterns separated from each other are located between two adjacent rectangular openings between two adjacent corners. The phase shift mask according to claim 1, wherein the light transmittance of the phase shift layer is 3% to 12%. The phase shift mask as claimed in claim 1, wherein the material of the phase shift layer includes molybdenum silicide or molybdenum silicon oxynitride. The phase-shift mask according to claim 1 further includes: an opaque boundary pattern disposed on the phase-shift layer and surrounding the plurality of rectangular openings and the plurality of opaque auxiliary patterns.

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