CN110828301A - Method for forming pattern - Google Patents

Abstract

The present application relates to the field of semiconductor integrated circuits, and discloses a method for forming a pattern, comprising: providing a substrate with a hard mask layer, coating a photoresist layer on the hard mask layer, exposing and developing to form a convex dot pattern array, which includes a plurality of repeated unit areas, each of which is defined as a polygonal area surrounded by three or more convex dot patterns as corner points; depositing a self-aligned spacer layer on the convex dot pattern and the hard mask layer, wherein a first concave dot pattern is formed at the center of the repeated unit area; etching and removing the self-aligned spacer layer until the convex dot pattern is exposed and the hard mask layer is exposed at the bottom of the first concave dot pattern; removing the convex dot pattern so that the self-aligned spacer layer has a plurality of second concave dot patterns exposing the hard mask layer, the first concave dot pattern being located at the center of the second concave dot pattern; etching the hard mask layer to form a hole pattern, the hole pattern position corresponding to the first concave dot pattern and the second concave dot pattern; and removing the self-aligned spacer layer.

Description

Method for forming graphics

technical field

The present application relates to the field of semiconductor integrated circuits, and in particular, to a method for forming patterns.

Background technique

In modern electronic instruments, integrated circuits are continuously decreasing in size. In order to reduce feature size, the feature size of the components that form integrated circuits is also decreasing. Techniques to reduce feature size may include pitch multiplication techniques.

At present, the commonly used method for doubling the spacing is to deposit a sacrificial layer on the modified photoresist on the line spacing, and then etch the sacrificial layer, remove the photoresist, and etch the substrate layer, and finally achieve the doubling of the spacing. Effect. But the existing spacing multiplication method is limited to apply to line spacing, and not applicable to other aspects.

SUMMARY OF THE INVENTION

In order to achieve the above object, embodiments of the present application provide a method for forming a pattern, comprising:

providing a substrate on which a hard mask layer is provided;

coating a photoresist layer on the hard mask layer;

exposing and developing the photoresist layer to form an array of bump-like patterns including a plurality of repeating unit regions, each repeating-unit region being defined from perpendicular to the surface of the substrate Longitudinal observation of a polygonal area surrounded by three or more convex figures as corner points;

A self-aligned spacer layer is deposited on the bump pattern and the hard mask layer, the self-aligned spacer layer covering the top and side surfaces of the bump pattern and the exposed surface of the hard mask layer surface, and make the self-aligned spacer layer form a first pit pattern at the center of the repeating unit region;

Etching and removing the portion of the self-aligned spacer layer covering the top surface of the bump pattern until the bump pattern of the photoresist layer is exposed and exposed at the bottom of the first concave pattern out the hard mask layer;

removing the bump pattern of the photoresist layer, so that the self-aligned spacer layer has a plurality of second pit patterns exposing the hard mask layer, and the first pit patterns are located in a plurality of at the center of the second pit pattern;

etching the hard mask layer through the self-aligned spacer layer to form a hole pattern, the hole pattern positions corresponding to the first pit pattern and the second pit pattern; and

The self-aligned spacer layer is removed.

Optionally, the method further includes: etching the first pit pattern to enlarge and modify the opening size of the first pit pattern.

Optionally, the first pit pattern is etched by using a wet etch-back technique.

Optionally, the size of the first pit pattern is controlled by controlling the acid concentration and time of the etch back.

Optionally, after the first pit pattern is enlarged, the distance between the upper surface of the self-aligned spacer layer and the top surface of the bump pattern of the photoresist layer is the same as the first pit pattern. The distance between the bottom surface of the pattern and the surface of the hard mask layer is equal.

Optionally, the repeating unit region is a triangle surrounded by three adjacent convex point patterns as corner points.

Optionally, the repeating unit region is a rectangle surrounded by four adjacent bump patterns as corner points.

Optionally, the repeating unit region is a hexagon surrounded by corner points using bump patterns formed by two exposures respectively.

Optionally, the repeating unit region is a triangle surrounded by corner points with bump patterns formed by three exposures respectively.

Optionally, the first pit pattern is formed by self-alignment.

Through the above technical solution, a hole array with a required pitch multiplication can be formed, which can be applied to a DRAM array, can increase the density of capacitors, and improve the performance of the DRAM.

Additional features and advantages of the present application will be described in detail in the detailed description that follows.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, and together with the following specific embodiments, are used to explain the present application, but do not constitute a limitation to the present application. In the attached image:

1A schematically shows a top view of a structure obtained after exposing and developing a photoresist layer in a method for forming a pattern according to an embodiment of the present application;

FIG. 1B exemplarily shows a cross-sectional view along the cutting line of FIG. 1A;

2A exemplarily shows a top view of a structure obtained after depositing a self-aligned spacer layer in a method for forming a pattern according to an embodiment of the present application;

FIG. 2B exemplarily shows a cross-sectional view along the cutting line of FIG. 2A;

3A exemplarily shows a top view of a structure obtained by enlarging an opening size of a first pit pattern of a self-aligned spacer layer in a method for forming a pattern according to an optional embodiment of the present application;

FIG. 3B exemplarily shows a cross-sectional view along the cutting line of FIG. 3A;

4A exemplarily shows a top view of a structure obtained after etching and removing a portion of the self-aligned spacer layer in the method for forming a pattern according to an embodiment of the present application;

FIG. 4B exemplarily shows a cross-sectional view along the cutting line of FIG. 4A;

5A exemplarily shows a top view of a structure obtained after removing a bump pattern of a photoresist layer in a method for forming a pattern according to an embodiment of the present application;

FIG. 5B exemplarily shows a cross-sectional view along the cutting line of FIG. 5A;

6A exemplarily shows a top view of a structure obtained after etching a hard mask layer in a method for forming a pattern according to an embodiment of the present application;

FIG. 6B exemplarily shows a cross-sectional view along the cutting line of FIG. 6A;

FIGS. 7A to 7B exemplarily show an example of using a wet etch-back technique to etch the first pit pattern to enlarge the opening size of the first pit pattern according to an embodiment of the present application;

8 exemplarily shows that the first pit pattern can be formed at the center of the rectangle in an embodiment in which the repeating unit region can be triangular;

FIG. 9 exemplarily shows that the first pit pattern can be formed at the center of the rectangle in an embodiment in which the repeating unit region can be a rectangle;

Figures 10A-10C exemplarily illustrate the formation of a hole pattern in an embodiment in which the repeating unit region may be rectangular;

11 exemplarily shows a pattern array formed by a plurality of repeating unit regions in an embodiment in which the repeating unit region may be a rectangle, wherein the first pit pattern may be located at the center of the rectangle;

FIG. 12 exemplarily shows that the first pit pattern can be formed at the center of the hexagon in an embodiment in which the repeating unit region can be a hexagon;

Figures 13A-13C exemplarily illustrate the formation of a hole pattern in an embodiment in which the repeating unit region may be hexagonal;

14 exemplarily shows a pattern array formed by a plurality of repeating unit regions in an embodiment in which the repeating unit region may be a hexagon, wherein the first pit pattern may be located at the center of the hexagon;

15 exemplarily shows that the first concave point pattern can be formed at the center of the triangle in an embodiment in which the repeating unit region can be a triangle;

Figures 16A-16C exemplarily illustrate the formation of a hole pattern in an embodiment in which the repeating unit region may be triangular;

Figure 17 exemplarily shows a pattern array formed by a plurality of repeating unit regions in an embodiment in which the repeating unit region may be triangular, wherein the first pit pattern may be located at the center of the triangle.

Description of reference numerals

110 Substrate 112 Hardmask layer

120 Photoresist layer 122 Bump pattern

130 Self-aligned spacer layer 132 First pit pattern

140 Second pit pattern 150 Hole pattern

Detailed ways

The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, but not to limit the present application.

In this application, unless stated to the contrary, the use of directional words such as "above/above, below/below, left/left, right/right" generally refers to the upper , down, left, right. "Inside and outside" generally refers to the inside and outside relative to the contours of each component itself.

In the drawings, the shapes shown may vary depending on manufacturing processes and/or tolerances. Therefore, the exemplary embodiments of the present application are not limited to the specific shapes shown in the drawings, and may include shape changes caused during manufacturing. Furthermore, the various elements and regions in the figures are shown schematically only and thus the application is not limited to the relative sizes or distances shown in the figures.

1 (including 1A and 1B) to 6 (including 6A and 6B) illustrate flowcharts of a method for forming a pattern according to an embodiment of the present application. Referring to FIGS. 1 to 6 , the method for forming a pattern according to an embodiment of the present application may include the following steps.

The method may include providing a substrate 110 on which a hardmask layer 112 may be disposed. The hard mask layer 112 may be, for example, an inorganic thin film material produced by chemical vapor deposition (Chemical Vapor Deposition, CVD). The material of the hard mask layer 112 may include, but is not limited to, TiN, SiN, SiO2, and the like. A photoresist layer 120 may be coated on the hard mask layer 112 . As exemplarily shown in FIGS. 1A and 1B , the photoresist layer 120 may be exposed and developed to form an array of bump-like patterns. Exposure and development are part of the lithography technology, and will not be repeated here. The bump pattern array may include a plurality of repeating unit regions, and each repeat region may be defined as being surrounded by three or more bump patterns 122 as corner points when viewed in a longitudinal direction perpendicular to the surface of the substrate 110 polygonal area.

As exemplarily shown in FIGS. 2A and 2B , a self-aligned spacer layer 130 may be deposited on the bump pattern 122 and the hard mask layer 112 , and the self-aligned spacer layer 130 may cover the top surface of the bump pattern 122 and the hard mask layer 112 . The side surface and the exposed upper surface of the hard mask layer 112 make the self-aligned spacer layer 130 form a first pit pattern 132 (ie, including pits) at the center of the repeating unit region. The material of the self-aligned spacer layer 130 may include, but is not limited to, silicon oxide, polysilicon, photoresist, metal, and the like.

The first pit patterns 132 may be formed in a self-aligned manner. For example, a high step coverage deposition method can be used and the thickness of the self-aligned spacer layer 130 is insufficient to overcome the height difference between the bump pattern 122 and the hard mask layer 112, and the recesses can be naturally formed.

In a further or preferred embodiment of the present application, as exemplarily shown in FIGS. 3A and 3B , the first pit pattern 132 may be etched to expand and modify the opening size of the first pit pattern 132 . In an embodiment of the present application, the first pit pattern 132 may be etched by using a wet etch-back technique to enlarge the size of the opening of the first pit pattern 132 . In one example, the size of the first pit pattern 132 can be controlled by controlling the acid concentration and time of the etch back. FIGS. 7A to 7B illustrate an example in which the first pit pattern 132 is etched using a wet etch-back technique to enlarge the opening size of the first pit pattern 132 according to an embodiment of the present application.

As exemplarily shown in FIGS. 4A and 4B , after the recesses are formed, the portion of the self-aligned spacer layer 130 covering the top surface of the bump patterns 122 may be removed by etching until the bump patterns 122 of the photoresist layer 120 are exposed. , and the hard mask layer 112 is exposed at the bottom of the first pit pattern 132 .

As exemplarily shown in FIGS. 5A and 5B , the bump patterns 122 of the photoresist layer 120 are removed, so that the self-aligned spacer layer 130 has a plurality of second pit patterns 140 exposing the hard mask layer 112 , the first The pit pattern 132 is located at the center of the plurality of second pit patterns 140 . The manner of removing the photoresist layer 120 may adopt a technique known to those skilled in the art, for example, the photoresist layer 120 may be removed by using an organic solvent. After the photoresist layer 120 is removed, holes corresponding to the bump patterns 122 , ie, the second pit patterns 140 , are left in the hard mask layer 112 . At this time, both the first pit pattern 132 and the second pit pattern 140 expose the hard mask layer 112.

As exemplarily shown in FIGS. 6A and 6B , the hard mask layer 112 is etched through the self-aligned spacer layer 130 to form a hole pattern 150 , and the position of the hole pattern 150 may correspond to the first pit pattern 132 and the second pit pattern 132 dot pattern 140; and removal of self-aligned spacer layer 130.

After the above steps, a hole array with a required pitch multiplication can be formed, which can be applied to a DRAM array, can increase the density of capacitors, and improve the performance of the DRAM. In addition, in terms of process, a denser hole array can be formed without multiple exposures.

In the embodiment of the present application, after the first concave pattern 132 is enlarged, the distance between the upper surface of the self-aligned spacer layer 130 and the top surface of the bump pattern 122 of the photoresist layer 120 may be the same as that of the first concave pattern 132. The distance between the bottom surface of the dot pattern 132 and the surface of the hard mask layer 112 is equal. In this way, during the process of etching the self-aligned spacer layer 130 , the hard mask layer 112 can be exposed at the bottom of the first pit pattern 132 while the bump patterns 122 of the photoresist layer 120 are exposed during the etching process. . For example, the distance between the bottom surface of the first pit pattern 132 and the surface of the hard mask layer 112 and the distance between the upper surface of the self-aligned spacer layer 130 and the photoresist layer 120 can be controlled by controlling the acid concentration and time of the etch back. The distances between the top surfaces of the bump patterns 122 are equal.

The repeating unit region can include a variety of graphic patterns. In an embodiment of the present application, as exemplarily shown in FIG. 8 , the repeating unit region may be surrounded by three adjacent bump patterns 122 (shaded circles shown in the figure) as corner points. triangle. After exposing and developing the photoresist layer 120, a bump pattern 122 can be formed, and a dot array can be seen from a vertical direction (top view), as exemplarily shown in the left figure of FIG. 8, the repeating unit area can be composed of Three adjacent convex point patterns 122 serve as a triangle surrounded by corner points. The first concave dot pattern 132 is formed at the center position of the triangle, as exemplarily shown in the right diagram of FIG. 8 . After the above-mentioned method of forming patterns is performed, hole patterns 150 corresponding to the bump patterns 122 and the first concave pattern 132 are formed on the hard mask layer 112 .

In another embodiment of the present application, the repeating unit region may be a rectangle surrounded by four adjacent bump patterns 122 as corner points. FIG. 9 exemplarily shows that the first pit pattern 132 may be formed at the center of the rectangle in an embodiment in which the repeating unit region may be a rectangle. FIGS. 10A-10C exemplarily illustrate the formation of a hole pattern 150 in an embodiment in which the repeating unit region is rectangular. Those skilled in the art can understand that the steps of forming the hole pattern 150 in the embodiment of FIG. 10A to FIG. 10C are similar to those in the above-mentioned embodiment, so FIG. 10A to FIG. 10C only exemplarily show part of the process of forming the hole pattern 150. 11 exemplarily shows a pattern array formed by a plurality of repeating unit regions in an embodiment in which the repeating unit region is a rectangle, wherein the first pit pattern 132 is located at the center of the rectangle. Referring to FIGS. 9 , 10A to 10C and FIG. 11 , after performing the above-described pattern forming method, a hole pattern 150 corresponding to the bump pattern 122 and the first concave pattern 132 is formed on the hard mask layer 112 .

In yet another embodiment of the present application, the repeating unit region is a hexagon surrounded by corner points with bump patterns 122 formed by two exposures respectively. FIG. 12 exemplarily shows that the first pit pattern 132 may be formed at the center of the hexagon in an embodiment in which the repeating unit region may be a hexagon. Figures 13A-13C exemplarily illustrate the formation of a hole pattern 150 in an embodiment in which the repeating unit regions are hexagonal. Those skilled in the art can understand that the steps of forming the hole pattern 150 in the embodiment of FIGS. 13A to 13C are similar to those in the above-mentioned embodiments, so FIGS. 14 exemplarily shows a pattern array formed by a plurality of repeating unit regions in an embodiment in which the repeating unit region is a hexagon, wherein the first pit pattern 132 is located at the center of the hexagon. 12, 13A to 13C and 14, the pattern represented by 122a may be formed by the first exposure of the photoresist layer 120 (the hatched pattern is a vertical line), and the pattern represented by 122b may be formed on the photoresist layer 120. Layer 120 is formed by a second exposure (shaded pattern). After the above-mentioned method of forming patterns is performed, hole patterns 150 corresponding to the bump patterns 122 and the first concave pattern 132 are formed on the hard mask layer 112 .

In still another embodiment of the present application, the repeating unit region may be a triangle surrounded by corner points by the bump patterns 122 respectively formed by three exposures. FIG. 15 exemplarily shows that the first pit pattern 132 may be formed at the center of the triangle in an embodiment in which the repeating unit region may be a triangle. Figures 16A-16C exemplarily illustrate the formation of a hole pattern 150 in an embodiment where the repeating unit regions are triangular. Those skilled in the art can understand that the steps of forming the hole pattern 150 in the embodiment of FIGS. 16A to 16C are similar to those in the above-mentioned embodiment, so FIGS. 17 exemplarily shows a pattern array formed by a plurality of repeating unit regions in an embodiment in which the repeating unit region is triangular, wherein the first pit pattern 132 is located at the center of the triangle. 15, 16A to 16C and 17, the pattern represented by 122a may be the pattern formed by the first exposure of the photoresist layer 120 (the pattern indicated by the vertical line), and the pattern represented by 122b may be formed in the photoresist layer 120. The pattern formed by the second exposure of the photoresist layer 120 (the hatched pattern with oblique lines) and the pattern represented by 122c may be the pattern formed by the third exposure of the photoresist layer 120 (the hatched pattern with crossed lines). After the above-mentioned method of forming patterns is performed, hole patterns 150 corresponding to the bump patterns 122 and the first concave pattern 132 are formed on the hard mask layer 112 .

In an embodiment of the present application, a substrate 110 fabricated using any of the methods for forming a pattern described in any of the above-described embodiments is also provided. Specifically, referring to the drawings, the substrate 110 may include a hard mask layer 112 , and the hard mask layer 112 may have a hole pattern 150 . The hole pattern 150 may include a first hole pattern array and a second hole pattern array. The first hole pattern array may correspond to the bump pattern 122 , and the second hole pattern array may correspond to the first concave pattern 132 . That is, the layouts of the first hole pattern array and the second hole pattern array may be the same as or correspond to those of the bump patterns 122 and the first concave pattern 132 described with reference to FIGS. 8 to 17 .

More specifically, in one embodiment of the present application, the first hole pattern array may include a plurality of repeating unit regions, and each repeating unit region may be defined as three or more The three or more first hole patterns are polygonal regions surrounded by corner points, and one second hole pattern in the second hole pattern array can be located at the center of a repeating unit region.

The repeating unit region can include a variety of graphic patterns. In one embodiment of the present application, the repeating unit region may be a triangle surrounded by three adjacent first hole patterns as corner points.

In another embodiment of the present application, the repeating unit region may be a rectangle surrounded by four adjacent first hole patterns as corner points.

In yet another embodiment of the present application, the repeating unit region may be a hexagon surrounded by six first hole patterns as corner points. The six first hole patterns may correspond to bump patterns 122 respectively formed by two exposures.

In yet another embodiment of the present application, the repeating unit region may be a triangle surrounded by nine first hole patterns as corner points. The nine first hole patterns may correspond to the nine bump patterns 122 formed by three exposures. The three bump patterns 122 formed by each exposure can be used as corner points to enclose a smaller triangle.

In the embodiment of the present application, a dynamic random access memory (Dynamic Random Access Memory, DRAM) including the above-mentioned substrate 110 is also provided.

The preferred embodiments of the present application have been described in detail above with reference to the accompanying drawings. However, the present application is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application. These simple modifications all belong to the protection scope of the present application.

In addition, it should be noted that each specific technical feature described in the above-mentioned specific implementation manner may be combined in any suitable manner under the circumstance that there is no contradiction. In order to avoid unnecessary repetition, various possible combinations are not described in this application.

In addition, the various embodiments of the present application can also be combined arbitrarily, as long as they do not violate the idea of the present application, they should also be regarded as the content disclosed in the present application.

Claims (10)

1. a method for forming a figure, it is characterised in that the method comprises: providing a substrate on which a hard mask layer is provided; coating a photoresist layer on the hard mask layer; exposing and developing the photoresist layer to form an array of bump-like patterns including a plurality of repeating unit regions, each repeating-unit region being defined from perpendicular to the surface of the substrate Longitudinal observation of a polygonal area surrounded by three or more convex figures as corner points; A self-aligned spacer layer is deposited on the bump pattern and the hard mask layer, the self-aligned spacer layer covering the top and side surfaces of the bump pattern and the exposed surface of the hard mask layer surface, and make the self-aligned spacer layer form a first pit pattern at the center of the repeating unit region; Etching and removing the portion of the self-aligned spacer layer covering the top surface of the bump pattern until the bump pattern of the photoresist layer is exposed and exposed at the bottom of the first concave pattern out the hard mask layer; removing the bump pattern of the photoresist layer, so that the self-aligned spacer layer has a plurality of second pit patterns exposing the hard mask layer, and the first pit patterns are located in a plurality of at the center of the second pit pattern; etching the hard mask layer through the self-aligned spacer layer to form a hole pattern, the hole pattern positions corresponding to the first pit pattern and the second pit pattern; and The self-aligned spacer layer is removed. 2. The method of claim 1, further comprising: The first pit pattern is etched to expand and modify the opening size of the first pit pattern. 3 . The method according to claim 2 , wherein the first pit pattern is etched by using a wet etch-back technique. 4 . 4. The method according to claim 3, wherein the size of the first pit pattern is controlled by controlling the acid concentration and time of the etch back. 5 . The method according to claim 2 , wherein after the first pit pattern is enlarged, the upper surface of the self-aligned spacer layer and the top surface of the bump pattern of the photoresist layer are formed. 6 . The distance therebetween is equal to the distance between the bottom surface of the first pit pattern and the surface of the hard mask layer. 6 . The method according to claim 1 , wherein the repeating unit region is a triangle surrounded by three adjacent convex point patterns as corner points. 7 . 7 . The method according to claim 1 , wherein the repeating unit region is a rectangle surrounded by four adjacent bump patterns as corner points. 8 . 8 . The method according to claim 1 , wherein the repeating unit region is formed of bump patterns formed by two exposures as a hexagon surrounded by corner points. 9 . 9 . The method according to claim 1 , wherein the repeating unit region is formed by three exposures respectively as a triangle surrounded by corner points. 10 . 10. The method according to any one of claims 1 to 9, wherein the first pit pattern is formed by a self-alignment method.

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