CN210776174U

CN210776174U - Combined light shield

Info

Publication number: CN210776174U
Application number: CN201921426031.8U
Authority: CN
Inventors: 童立峰; 杨要华
Original assignee: Shanghai Huali Microelectronics Corp
Current assignee: Shanghai Huali Microelectronics Corp
Priority date: 2019-08-29
Filing date: 2019-08-29
Publication date: 2020-06-16
Anticipated expiration: 2029-08-29

Abstract

The utility model provides a combination light shield, the combination light shield includes two at least light shields, has the figure on every light shield, each when the light shield overlaps, each the figure on the light shield is spaced each other, utilizes the exposure of combination light shield realizes the sequential exposure of a plurality of light shields under the condition of photoresist of spin-coating only on the MCT layer, can obtain ideal hole and lines on the MCT layer, has improved the characteristic dimension's of hole on the MCT layer precision with the lines, has reduced the degree of difficulty that OPC model modeled simultaneously.

Description

Combined light shield

Technical Field

The utility model relates to a semiconductor manufacturing technical field, in particular to combination light shield.

Background

As integrated circuits become more complex, feature sizes become smaller and smaller. When the feature size of an integrated circuit approaches the system limit of exposure of a lithography machine, i.e., the feature size is close to or smaller than the lithography light source, the layout fabricated on the silicon wafer can exhibit significant distortion, a phenomenon known as optical proximity effect. In order to cope with the optical proximity effect, a resolution enhancement technique has been developed, wherein Optical Proximity Correction (OPC) has become one of important techniques.

In a memory, a hole-line hybrid contact connection layer (MCT layer) is an important layer, feature patterns on the MCT layer have both holes and lines, and if the holes and the lines are simultaneously fabricated on a photomask, it is difficult to process an OPC model, because the existing OPC model cannot consider both the holes and the lines at the same time, and an upper computer performing OPC on the feature patterns can only consider that the feature patterns are both holes or both lines at present, one of the holes and the lines is usually selected as a pattern on the photomask, and the other one is directly used for rule compensation by the upper computer, but this easily results in low accuracy of feature sizes of the feature patterns finally formed on the MCT layer, and the existing method of performing OPC on the feature patterns having both holes and lines on the MCT layer is complicated, increases difficulty in modeling OPC, and has low working efficiency. In addition, it is difficult to process the OPC model when the distance between two rows of patterns on the same photomask is very small, and the conventional OPC model is likely to cause disconnection during etching of the MCT layer due to overlay variation when two rows of patterns with small distance on the same photomask are processed.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a combination light shield to solve the lower problem of characteristic figure characteristic dimension precision that forms on the MCT layer.

In order to solve the technical problem, the utility model provides a combined photomask, combined photomask includes two at least photomasks, every have the figure on the photomask, each when the photomask overlaps, each the figure on the photomask is spaced each other.

Optionally, in the combined mask, the combined mask includes: the photomask comprises a first photomask and a second photomask, wherein a first pattern is arranged on the first photomask, a second pattern is arranged on the second photomask, and when the first photomask and the second photomask are overlapped, the first pattern and the second pattern are mutually spaced.

Optionally, in the combined mask, the first pattern includes at least two lines arranged at intervals and parallel to each other.

Optionally, in the combined photomask, the first pattern includes a plurality of groups of adjacent lines, and distances between the plurality of groups of adjacent lines are the same.

Optionally, in the combined photomask, the first pattern includes a plurality of groups of adjacent lines, and distances between the plurality of groups of adjacent lines are different.

Optionally, in the combined photomask, the second pattern includes at least two rows of holes arranged at intervals and parallel to each other, and the number of the holes in each row is at least two.

Optionally, in the combined mask, the second pattern includes a plurality of groups of holes in adjacent rows, and distances between the plurality of groups of holes in adjacent rows are the same.

Optionally, in the combined mask, the second pattern includes a plurality of groups of holes in adjacent rows, and distances between the plurality of groups of holes in adjacent rows are different.

Optionally, in the combined mask, when the first mask and the second mask overlap, each line and each row of the holes are spaced apart from each other.

Optionally, in the combined mask, the combined mask further includes: and the third photomask is provided with a third pattern, and when the first photomask, the second photomask and the third photomask are overlapped, the first pattern, the second pattern and the third pattern are mutually spaced.

To sum up, the utility model provides a combination light shield, the combination light shield includes two at least light shields, has the figure on every light shield, each when the light shield overlaps, each the figure on the light shield is spaced each other, utilizes the order exposure of combination light shield exposure realization a plurality of light shields under the condition of the photoresist of spin-coating on the MCT layer only can obtain ideal hole and lines on the MCT layer, has improved the characteristic dimension's of hole on the MCT layer precision with the lines, has reduced the degree of difficulty that the OPC model was modeled simultaneously.

Drawings

Fig. 1 is a schematic view of a combined mask according to a first embodiment of the present invention;

fig. 2 is a schematic view of a combination of a first mask and a second mask according to a first embodiment of the present invention;

fig. 3 is a schematic view of a first mask according to a first embodiment of the present invention;

FIG. 4 is a schematic diagram of a second mask according to a first embodiment of the present invention;

FIG. 5 is a schematic view of a second embodiment of the present invention;

fig. 6 is a schematic combination diagram of the first mask, the second mask and the third mask according to the second embodiment of the present invention;

FIG. 7 is a schematic view of a third mask according to a second embodiment of the present invention;

in the figure, the position of the upper end of the main shaft,

10-first mask, 11-first pattern, 20-second mask, 21-second pattern, 30-third mask, 31-third pattern, 100-combined mask.

Detailed Description

The combined photomask according to the present invention will be described in detail with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more fully apparent from the following description and appended claims. It should be noted that the drawings are in simplified form and are not to precise scale, and are provided for convenience and clarity in order to facilitate the description of the embodiments of the present invention.

The utility model discloses people's research discovers, current OPC model can not compromise hole and lines simultaneously, the host computer can only think the figure all be the hole or all be the lines, so select one of them as the figure on the light shield between hole and lines usually, for example adopt the light shield that has the figure of hole, appear the line in the figure, can only do not do the processing to the line earlier, perhaps, regard the line as the slot hole and carry out OPC processing, there is the extreme point if the slot hole, the line will be revised into the cockscomb structure by OPC model like this, lead to the final hole that forms on the wafer and the characteristic dimension's of lines precision lower.

Therefore, the utility model discloses real core thought lies in providing a combination light shield, the combination light shield includes: the combined photomask is used for exposure to obtain better holes and lines on the MCT layer, so that the problem of low feature size precision of feature patterns formed on the MCT layer can be solved, and the difficulty of OPC model modeling is reduced.

Example one

Please refer to fig. 1, fig. 2, fig. 3 and fig. 4, in which fig. 1 is a schematic diagram of a first combined photomask of the present invention, fig. 2 is a schematic diagram of a first photomask and a second photomask of the present invention, fig. 3 is a schematic diagram of a first photomask of the present invention, fig. 4 is a schematic diagram of a second photomask of the first embodiment of the present invention, and the combined photomask 100 includes: the photomask comprises a first photomask 10 and a second photomask 20, wherein a first pattern 11 is arranged on the first photomask 10, a second pattern 21 is arranged on the second photomask 20, and when the first photomask 10 and the second photomask 20 are overlapped, the first pattern 11 and the second pattern 21 are mutually spaced and do not generate any intersection.

Further, as shown in fig. 3, the first pattern 11 on the first mask 10 has at least two lines that are arranged at intervals and are parallel to each other, and distances between two adjacent lines may be the same or different, that is, the lines on the first mask 10 may be distributed at the same interval distance or at different interval distances, a distance between two adjacent lines is usually set to be twice or more of a line width of the line, and generally, twice to three times of the line width of the line is taken as an interval distance between the lines, a line width of the line on the first mask 10 is between 14nm and 60nm, for example, 14nm, 50nm, and the like, for example, a line width of the line on the first mask 10 is 14nm, and a distance between two adjacent lines may be set to be 28nm, 42nm, and the like; for example, if the line width of the lines on the first mask 10 is 50nm, the distance between two adjacent lines may be set to 100nm, 150nm, or the like. In this embodiment, the first pattern 11 on the first mask 10 has three lines that are arranged at intervals and are parallel to each other, and the distance between two adjacent lines is the same, the line width of the line on the first mask 10 is 60nm, and the distance between two adjacent lines is set to be 120 nm.

Further, as shown in fig. 4, the second pattern 21 on the second mask 20 has at least two rows of holes arranged at intervals and parallel to each other, and the number of the holes in each row is at least two. In general, because the feature size of the holes on the second mask 20 is small, the second mask 20 looks like an intermittent line in each row when viewed at a small magnification. The distance between two adjacent rows of holes may be the same or different, that is, the holes in each row of the second mask 20 may be distributed at the same interval distance or at different interval distances, and the distance between two adjacent rows of holes may be set to be greater than or equal to 120 nm. In the embodiment, the second pattern 21 on the second mask 20 has three rows of holes, each row has 6 holes, and the distance between two adjacent rows of holes is different, as shown in fig. 4, the distance between the first row of holes and the second row of holes from left to right may be 120nm, and the distance between the second row of holes and the third row of holes may be 140 nm.

As shown in fig. 1, after the first photomask 10 and the second photomask 20 are sequentially and respectively exposed and developed on the photoresist layer on the surface of the MCT layer by using an exposure machine, the first photomask 10 and the second photomask 20 can be seen to overlap on the photoresist layer, the lines and the holes are mutually spaced, and the spacing between each row of the lines and the holes is 0 to 185nm, for example, 10nm, 15nm, 20nm, and the like. The first photomask and the second photomask are subjected to OPC treatment in advance, so that the feature size of a photoresist layer graph obtained by subsequently exposing the combined photomask and the feature size precision of holes and lines obtained by etching the MCT layer can be ensured, and the difficulty of OPC model modeling is reduced.

In this embodiment, a method for forming holes and lines on an MCT layer using the combined mask 100 includes: performing OPC processing on the first photomask 10 and the second photomask 20, respectively; spin-coating a photoresist layer on the MCT layer; exposing the first photomask 10 by using an exposure machine to obtain a line pattern on the photoresist layer; and continuing to expose the second photomask 20 by using an exposure machine to obtain a hole pattern on the photoresist layer, wherein at the moment, a combined pattern with intervals between each line and each row of holes is obtained on the photoresist layer. The MCT layer to be etched is coated with glue once, and the first photomask 10 and the second photomask 20 are exposed and developed on the same photoresist layer respectively, so that the accuracy of the characteristic size of holes and lines formed on the photoresist layer is improved, the accuracy of the characteristic size of the holes and the lines formed on the MCT layer subsequently is improved, and ideal holes and lines can be obtained during the subsequent etching of the MCT layer.

Example two

In this embodiment, referring to fig. 5, fig. 6 and fig. 7, fig. 5 is a schematic diagram of a combined mask according to a second embodiment of the present invention, fig. 6 is a schematic diagram of a combination of a first mask, a second mask and a third mask according to a second embodiment of the present invention, and fig. 7 is a schematic diagram of a third mask according to a second embodiment of the present invention. As shown in fig. 5, the combined mask 100 includes: as shown in fig. 6, the first mask 10 has a first pattern 11 thereon, the second mask 20 has a second pattern 21 thereon, and the third mask 30 has a third pattern 31 thereon, such that when the first mask 10, the second mask 20 and the third mask 30 are overlapped, the first pattern 11, the second pattern 21 and the third pattern 31 are spaced apart from each other and do not intersect with each other.

As shown in fig. 7, the third pattern 31 on the third mask 30 is a line, and after each mask in the combined mask 100 is exposed and developed, a distance between the line on the third mask 30 and a line pattern formed on the photoresist layer by the line on the first mask 10 is greater than or equal to 14 nm.

In this embodiment, a photoresist layer is formed on the MCT layer to be etched, and the first mask 10, the second mask 20, and the third mask 30 are respectively used for exposure and development on the photoresist layer, so that the accuracy of the feature sizes of the lines and holes formed on the photoresist layer is improved, the situation that the combined mask patterns with very small distances between rows and columns are broken when the MCT layer is etched due to overlay deviation is avoided, the accuracy of the feature sizes of the process windows of the lines and holes formed on the MCT layer subsequently is improved, and ideal lines and holes can be obtained when the MCT layer is subsequently etched.

The parts not described in the second embodiment can be referred to the first embodiment, and the second embodiment is not described again.

The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and any modification and modification made by those skilled in the art according to the above disclosure are all within the scope of the claims.

Claims

1. A combined photomask comprises at least two photomasks, each photomask is provided with a pattern, and when the photomasks are overlapped, the patterns on the photomasks are mutually spaced.

2. The composite reticle of claim 1, wherein the composite reticle comprises: the photomask comprises a first photomask and a second photomask, wherein a first pattern is arranged on the first photomask, a second pattern is arranged on the second photomask, and when the first photomask and the second photomask are overlapped, the first pattern and the second pattern are mutually spaced.

3. The composite mask of claim 2 wherein said first pattern comprises at least two spaced apart parallel lines.

4. The composite mask of claim 3 wherein said first pattern comprises a plurality of sets of adjacent lines, said sets of adjacent lines having the same distance therebetween.

5. The composite mask of claim 3 wherein said first pattern comprises a plurality of sets of adjacent lines, said sets of adjacent lines having different distances therebetween.

6. The composite mask of claim 2, wherein the second pattern comprises at least two spaced rows of parallel holes, each row comprising at least two holes.

7. The composite mask of claim 6, wherein the second pattern comprises a plurality of adjacent rows of holes, and the distance between the plurality of adjacent rows of holes is the same.

8. The composite mask of claim 6, wherein the second pattern comprises a plurality of adjacent rows of holes, the plurality of adjacent rows of holes having different distances therebetween.

9. The composite reticle of claim 2, further comprising: and the third photomask is provided with a third pattern, and when the first photomask, the second photomask and the third photomask are overlapped, the first pattern, the second pattern and the third pattern are mutually spaced.