阅读说明：本技术 对位标记和半导体结构的形成方法、组合掩膜版 (Alignment mark and semiconductor structure forming method and combined mask ) 是由 巫奉伦 王嘉鸿 夏忠平 黄建维 于 2019-11-04 设计创作，主要内容包括：本发明提供了一种对位标记和半导体结构的形成方法、组合掩模版。通过组合使用第一掩模版和第二掩模版,以界定出对位标记的图形,从而使得所形成的对位标记的结构更为复杂且精度更高,进而基于该对位标记执行光刻工艺时,即有利于提高光刻工艺的对准精度,减小光刻工艺的对位偏差。以及,在将该对位标记结合至半导体器件的制备过程中,则相应的能够提高所形成的半导体器件的性能。(The invention provides a method for forming an alignment mark and a semiconductor structure and a combined mask. The first mask and the second mask are used in a combined mode to define the graph of the alignment mark, so that the structure of the formed alignment mark is more complex and higher in precision, and when the photoetching process is executed based on the alignment mark, the alignment precision of the photoetching process is improved, and the alignment deviation of the photoetching process is reduced. And in the manufacturing process of combining the alignment mark with the semiconductor device, the performance of the formed semiconductor device can be correspondingly improved.)

1. A combinatorial reticle, comprising:

a first mask having a first pattern formed thereon;

and the second mask is provided with a second pattern, and the second pattern is used for being combined with the first pattern to define a pattern of an alignment mark.

2. The combinatorial reticle of claim 1, the second pattern and the first pattern being superimposed on each other to define the pattern of the alignment marks.

3. The combinatorial reticle of claim 1, wherein the second pattern and the first pattern overlap each other to define the pattern of the alignment mark.

4. The combinatorial reticle of claim 1, the second pattern and the first pattern non-overlapping portions defining a pattern of the alignment mark.

5. The combinatorial reticle of claim 1, wherein the first reticle and the second reticle each have a clear area, and wherein the clear areas of the first reticle and the clear areas of the second reticle correspond in shape and position to one another.

6. The combinatorial reticle of claim 5, wherein the first reticle and the second reticle each have a pattern area, the pattern areas of the first reticle and the second reticle correspond in shape and position to each other, and the pattern areas are embedded in the blank areas.

7. The combinatorial reticle of claim 1, wherein the first pattern comprises a plurality of first lines and the second pattern comprises a plurality of second lines;

wherein, when the first pattern and the second pattern are combined, the first line and the second line intersect to define an aperture array pattern or an island array pattern.

8. The reticle of claim 7, wherein the first lines and the second lines are non-perpendicular such that the defined pattern of the array of holes is in a hexagonal array or the defined pattern of the array of islands is in a hexagonal array.

9. The combinatorial reticle of claim 1, wherein the first pattern comprises a plurality of first block patterns aligned in a first direction, wherein the second pattern comprises a plurality of second block patterns aligned in the first direction;

wherein, when the first pattern and the second pattern are combined, the first block patterns and the second block patterns are alternately connected in the first direction and are superimposed on each other to define a chain pattern connected in series.

10. The combinatorial reticle of claim 1, wherein the first pattern comprises a plurality of first block patterns aligned in a first direction, wherein the second pattern comprises a plurality of second block patterns aligned in the first direction;

wherein the first block patterns and the second block patterns are alternately connected in the first direction when the first pattern and the second pattern are combined, and a block array pattern is defined by a portion where the first block patterns and the second block patterns overlap each other at the connection.

11. The combinatorial reticle of claim 9 or 10, wherein the first block pattern and the second block pattern are both elliptical in shape, and wherein the major axis directions of the ellipses of the first block pattern and the second block pattern are both the first direction.

12. The combinatorial reticle of claim 1, wherein the first pattern comprises a plurality of first blocky patterns, the second pattern comprises a plurality of second blocky patterns, and a size of the second blocky patterns is smaller than a size of the first blocky patterns;

wherein when the first graphic and the second graphic are combined, the centers of the first block pattern and the second block pattern coincide to define a ring-shaped graphic.

13. A method for forming an alignment mark, comprising:

performing a first photoetching process by using a first mask plate to form a first pattern on a target layer;

performing a second photoetching process by using a second mask to form a second pattern on the target layer, and defining a pattern of an alignment mark by using the second pattern and the first pattern;

and performing an etching process to copy the pattern of the alignment mark to the target layer, and forming the alignment mark in the target layer.

14. The method for forming an alignment mark according to claim 13, wherein the second pattern and the first pattern are superimposed on each other after the first photolithography process and the second photolithography process are performed to form the pattern of the alignment mark.

15. The method for forming an alignment mark according to claim 13, wherein the second pattern partially covers the first pattern after the second photolithography process is performed;

and before the etching process is executed, further comprising: and removing the part of the first graph which is not covered by the second graph, and reserving the part of the first graph which is covered by the second graph to form the graph of the alignment mark.

16. The method for forming an alignment mark according to claim 13, wherein the target layer is a conductive layer.

17. A combined mask, wherein the combined mask is used for defining a pattern of an alignment mark in an alignment mark area and also used for defining a pattern of a device film layer in a semiconductor device area, wherein the combined mask comprises:

the mask comprises a first mask, a second mask and a third mask, wherein a first alignment pattern is formed in an alignment mark area of the first mask, and a first device pattern is formed in a semiconductor device area of the first mask;

the second mask plate is provided with a second alignment pattern in an alignment mark area, the second alignment pattern is used for being combined with the first alignment pattern to define a pattern of an alignment mark, a second device pattern is formed in a semiconductor device area of the first mask plate, and the second device pattern is used for being combined with the first device pattern to define a pattern of a device film layer.

18. The combinatorial reticle of claim 17, wherein the first alignment pattern is the same pattern as the first device pattern and the second alignment pattern is the same pattern as the second device pattern.

19. A method of forming a semiconductor structure, comprising:

providing a reticle of claim 17;

performing a first photoetching process by using a first mask to form a first alignment pattern in an alignment mark area of a target layer and form a first device pattern in a semiconductor device area of the target layer;

performing a second photoetching process by using a second mask to form a second alignment pattern in the alignment mark area of the target layer and a second device pattern in the semiconductor device area of the target layer, wherein the second alignment pattern and the first alignment pattern define a pattern of an alignment mark, and the first device pattern and the second device pattern define a pattern of a device film layer;

performing an etching process to copy the pattern of the alignment mark and the pattern of the device film layer into the target layer;

and providing a third mask and executing a third photoetching process, wherein the third photoetching process carries out pattern alignment by identifying the alignment marks.

Technical Field

The invention relates to the technical field of semiconductors, in particular to a combined mask, a forming method of a contraposition mark and a forming method of a semiconductor structure.

Background

With the continuous development of semiconductor technology, the process nodes of semiconductor devices are continuously decreasing, and the film structures in semiconductor devices are more complicated, for which the alignment precision between the films is particularly important. Specifically, in the preparation of sequentially stacked patterned film layers, it is common to copy the pattern on each reticle into the corresponding film layer in conjunction with a photolithography process. When the photolithography process is performed, the alignment mark is generally recognized to achieve that the pattern on the current mask can be aligned with the pattern of the lower film layer.

Therefore, the alignment marks play a crucial role in the photolithography process, and the alignment deviation between the film layers can be directly influenced. Particularly, as semiconductor technology is continuously developed, the number of film layers in a device is continuously increased, and alignment deviations among the film layers are also superposed, so that the performance of the formed semiconductor device is seriously affected.

Disclosure of Invention

The invention aims to provide a combined mask which can be used for defining a pattern of an alignment mark so as to improve the alignment precision of a photoetching process.

In order to solve the above technical problem, the present invention provides a combined mask, comprising:

a first mask having a first pattern formed thereon;

and the second mask is provided with a second pattern, and the second pattern is used for being combined with the first pattern to define a pattern of an alignment mark.

Based on the combined mask, the invention also provides a method for forming the alignment mark, which comprises the following steps:

performing a first photoetching process by using a first mask plate to form a first pattern on a target layer;

performing a second photoetching process by using a second mask to form a second pattern on the target layer, and defining a pattern of an alignment mark by using the second pattern and the first pattern;

and performing an etching process to copy the pattern of the alignment mark to the target layer, and forming the alignment mark in the target layer.

The invention also provides a combined mask, wherein the combined mask is used for defining the pattern of the alignment mark in the alignment mark area and defining the pattern of the device film layer in the semiconductor device area. Wherein the combinatorial reticle comprises:

the mask comprises a first mask, a second mask and a third mask, wherein a first alignment pattern is formed in an alignment mark area of the first mask, and a first device pattern is formed in a semiconductor device area of the first mask;

the second mask plate is provided with a second alignment pattern in an alignment mark area, the second alignment pattern is used for being combined with the first alignment pattern to define a pattern of an alignment mark, a second device pattern is formed in a semiconductor device area of the first mask plate, and the second device pattern is used for being combined with the first device pattern to define a pattern of a device film layer.

Based on the combined mask plate, the invention also aims to provide a method for forming a semiconductor structure, which comprises the following steps:

providing a combinatorial reticle as described above;

performing a first photoetching process by using a first mask to form a first alignment pattern in an alignment mark area of a target layer and form a first device pattern in a semiconductor device area of the target layer;

performing a second photoetching process by using a second mask to form a second alignment pattern in the alignment mark area of the target layer and a second device pattern in the semiconductor device area of the target layer, wherein the second alignment pattern and the first alignment pattern define a pattern of an alignment mark, and the first device pattern and the second device pattern define a pattern of a device film layer;

performing an etching process to copy the pattern of the alignment mark and the pattern of the device film layer into the target layer;

and providing a third mask and executing a third photoetching process, wherein the third photoetching process carries out pattern alignment by identifying the alignment marks.

The combined mask provided by the invention can be used for defining a pattern of an alignment mark. Namely, the pattern of the alignment mark is defined by the combination of the first mask and the second mask. Therefore, compared with the traditional alignment mark, the alignment mark formed in the invention has more complex patterns and higher precision, so that when the photoetching process is performed on the basis of the alignment mark in the subsequent process, the identification precision of the alignment mark can be improved, and the alignment deviation of the photoetching process is reduced.

In addition, the combined mask is beneficial to improving the performance of the formed semiconductor device in the manufacturing process of combining the combined mask with the semiconductor device. Specifically, the same double-pattern lithography process can be used to form a device film layer and also form a registration mark, and the deviation condition of the formed device film layer can be reflected through the registration mark; and moreover, the alignment mark is also integrated with the deviation of the first photoetching process and the deviation of the second photoetching process, so that when the third photoetching process is executed based on the alignment mark, the third photoetching process can realize pattern alignment on the basis of balancing the alignment deviation of the first photoetching process and the alignment deviation of the second photoetching process, and is favorable for reducing the total deviation generated by the first photoetching process, the second photoetching process and the third photoetching process.

Drawings

FIG. 1 is a schematic structural diagram of a reticle assembly according to a first embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a reticle set according to a second embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a reticle set according to a third embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a reticle set according to a fourth embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a reticle assembly according to a fifth embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a reticle assembly according to a sixth embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a reticle assembly according to a seventh embodiment of the present invention.

Wherein the reference numbers are as follows:

100A/200A/300A/400A/500A/600A-first reticle;

100B/200B/300B/400B/500B/600B-second reticle;

110A/210A/310A/410A-first line;

110B/210B/310B/410B-second line;

120A/320A-first blank area;

120B/320B-second white space region;

220A/420A-first graphics region;

220B/420B-second graphics area;

510A/610A-first patch pattern;

510B/610B-a second block pattern;

100A/200A/300A/400A/500A/500C'/600A-pattern of alignment marks.

Detailed Description

The combined mask, the method for forming the alignment mark, and the method for forming the semiconductor structure according to the present invention will be described in further detail with reference to the accompanying drawings and the embodiments. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.