CN115692175A - Method for forming monitoring pattern and pattern monitoring method - Google Patents

Abstract

The present disclosure provides a method for forming a monitoring pattern and a pattern monitoring method, wherein the method for forming the monitoring pattern comprises: providing a material layer to be etched, sequentially forming a preset number of hard mask layers on the surface of the material layer to be etched, wherein the finally formed hard mask layer comprises a plurality of mandrels, and the length of at least one mandrel in the direction in which the mandrels are parallel to each other is different from that of other mandrels; forming a side wall positioned around the patterned hard mask layer, then removing the patterned hard mask layer, etching the hard mask layer adjacent to the bottom of the side wall by taking the side wall as a mask, and then removing the side wall to form a new patterned hard mask layer; repeating the process for forming the patterned hard mask layer for a plurality of times to form a monitoring pattern on the hard mask layer adjacent to the material layer to be etched, and then transferring the monitoring pattern to the material layer to be etched. The method can monitor each process of the multiple graphic technology and improve the yield.

Description

Method for forming monitoring pattern and pattern monitoring method

Technical Field

The present disclosure relates to the field of semiconductor technologies, and in particular, to a method for forming a monitoring pattern and a method for monitoring a pattern.

Background

As the minimum line width and minimum pitch of integrated circuit designs continue to shrink, as feature sizes of pattern lines approach the theoretical resolution limit of the exposure system, the lithographic imaging can be severely distorted due to optical proximity effects, resulting in severe degradation of the quality of the lithographic pattern. To reduce the effect of optical proximity effect, the industry has proposed lithographic resolution enhancement techniques, such as double exposure techniques, self-aligned double patterning techniques, self-aligned quadruple patterning techniques.

However, as the feature size of the device is smaller and smaller, the requirement for the quality of the pattern formed by the multiple patterning technology is higher and higher, and when the quality of the finally obtained pattern does not meet the process requirement, the related process needs to be perfected. For example, whether the widths of the resulting individual pattern lines are equal or different as desired, and if the desired effect is not achieved, how to determine in which process the problem arises. The monitoring method for the quality of the patterns in the related art cannot meet the requirement of monitoring the process of the multiple-pattern technology.

Therefore, a new monitoring method is needed to monitor the process of the multi-patterning technology.

Disclosure of Invention

The present disclosure provides a method for forming a monitoring pattern and a method for monitoring a pattern, so as to monitor a process of a multiple pattern technology by using the formed monitoring pattern, thereby being capable of improving the process of the multiple pattern technology in a targeted manner according to a monitoring result.

The present disclosure provides a method for forming a monitor pattern, including: providing a material layer to be etched, sequentially forming a preset number of hard mask layers on the surface of the material layer to be etched, wherein the finally formed hard mask layer is a graphical hard mask layer, the finally formed hard mask layer comprises a plurality of mandrels, the mandrels are parallel to each other, and the length of at least one mandrel in the direction in which the mandrels are parallel to each other is different from that of other mandrels; forming a side wall positioned around the patterned hard mask layer, then removing the patterned hard mask layer, etching the hard mask layer adjacent to the bottom of the side wall by taking the side wall as a mask, and then removing the side wall to form a new patterned hard mask layer; repeating the process for forming the patterned hard mask layer for a plurality of times to form a monitoring pattern on the hard mask layer adjacent to the material layer to be etched, and then transferring the monitoring pattern to the material layer to be etched.

In one embodiment, the process of patterning the finally formed hard mask layer includes: forming a photoetching layer on the finally formed hard mask layer; and photoetching the photoetching layer to form a patterned photoetching layer, etching the finally formed hard mask layer by taking the patterned photoetching layer as a mask, and removing the patterned photoetching layer to form the patterned hard mask layer.

In one embodiment, the process of forming the sidewall spacers around the patterned hard mask layer includes: forming a side wall material layer covering the graphical hard mask layer; and etching back the side wall material layer, wherein the side wall material layer positioned around the patterned hard mask layer forms a side wall.

In an embodiment, the process of forming the spacer material layer includes atomic layer deposition.

In an embodiment, the process of etching back the spacer material layer includes dry etching.

In one embodiment, the method further comprises: forming a sacrificial layer between the adjacent hard mask layers; and etching the hard mask layer adjacent to the bottom of the side wall by using the side wall as a mask, and then removing the side wall to form a new graphical hard mask layer, wherein the method comprises the following steps: etching the sacrificial layer adjacent to the bottom of the side wall by taking the side wall as a mask, and then removing the side wall to form a patterned sacrificial layer; and taking the patterned sacrificial layer as a mask, etching the hard mask layer adjacent to the bottom of the patterned sacrificial layer, and then removing the patterned sacrificial layer to form a new patterned hard mask layer.

In one embodiment, the materials of the side walls and the hard mask layer are different, so that the etching rates of the side walls and the hard mask layer are different.

In one embodiment, the hard mask layer is made of silicon oxide, silicon nitride, silicon oxynitride, carbon, titanium nitride, or tantalum nitride.

In one embodiment, the width of the sidewall is in a range of 5-20 nm.

In one embodiment, the material layer to be etched on which the monitoring pattern is formed includes 4 times as many fins as the number of mandrels in the arrangement direction of the mandrels.

The present disclosure provides a pattern monitoring method, based on the monitoring pattern formed by the above method for forming a monitoring pattern, including: acquiring a third distance between two adjacent pattern lines with different lengths in the pattern lines of the monitoring pattern extending in the direction parallel to the mandrel; and judging whether the monitoring graph meets the preset requirement or not according to the third distance.

In an embodiment, in the case that it is determined that the monitoring pattern does not satisfy the preset requirement according to the third distance, the method further includes: and adjusting the distance between the adjacent mandrels corresponding to the third distance by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the third distance.

In one embodiment, the method further comprises: acquiring a second distance adjacent to the third distance; judging whether the monitoring graph meets the preset requirement according to the third distance, comprising the following steps of: and judging whether the monitoring graph meets the preset requirement or not according to the second distance and/or the third distance.

In an embodiment, in the case that it is determined that the monitoring pattern does not satisfy the preset requirement according to the second pitch and/or the third pitch, the method further includes: under the condition that the size of the second distance does not meet the preset requirement, the thickness of the side wall corresponding to the second distance is adjusted by adjusting the process for forming the side wall corresponding to the second distance, so that the adjustment of the second distance is realized; under the condition that the size relation between the second distance and the third distance does not meet the preset requirement: adjusting the thickness of the side wall corresponding to the second distance by adjusting the process of forming the side wall corresponding to the second distance so as to realize the adjustment of the second distance; and/or adjusting the distance between the adjacent mandrels corresponding to the third distance by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the third distance.

In one embodiment, the method further comprises: acquiring a first distance in a direction adjacent to the second distance and far away from the third distance; judging whether the monitoring graph meets the preset requirement according to the third distance, comprising the following steps of: and judging whether the monitoring pattern meets the preset requirement according to at least one of the first spacing, the second spacing and the third spacing.

In an embodiment, in the case that it is determined that the monitoring pattern does not satisfy the preset requirement according to at least one of the first pitch, the second pitch, and the third pitch, the method further includes: under the condition that the size of the first interval does not meet the preset requirement, the length of the mandrels corresponding to the first interval in the arrangement direction of each mandrel is adjusted by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the first interval; under the condition that the size relation among the first distance, the second distance and the third distance does not meet the preset requirement; adjusting the lengths of the mandrels corresponding to the first interval in the arrangement direction of the mandrels by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the first interval; and/or adjusting the thickness of the side wall corresponding to the second distance by adjusting the process of forming the side wall corresponding to the second distance so as to adjust the second distance; and/or adjusting the distance between the adjacent mandrels corresponding to the third distance by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the third distance.

The monitoring graph formed by the method for forming the monitoring graph and the corresponding graph monitoring method can monitor the technological process of the multiple graph technology, so that the technological process of the multiple graph technology can be improved in a targeted manner, and the yield is improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and not to limit the disclosure, in which:

FIG. 1 is a flow chart of a method of forming a monitor pattern according to an exemplary embodiment of the present disclosure;

FIGS. 2A to 2I are schematic cross-sectional views illustrating a process of forming a monitor pattern according to an embodiment of the present disclosure;

FIG. 3 is a diagram illustrating a corresponding relationship between a process of a quad scheme technique and a trench width in the related art;

FIGS. 4A-4G are schematic top views illustrating a process of forming a monitor pattern according to an embodiment of the present disclosure;

fig. 5A to 5C are schematic cross-sectional structure diagrams illustrating a patterning process of a hard mask layer finally formed on a first material layer to be etched according to an embodiment of the disclosure;

fig. 6A to 6E are schematic cross-sectional views illustrating a process of forming a monitor pattern according to another embodiment of the present disclosure.

Wherein the reference numerals are as follows:

100. a first material layer to be etched;

110. a first hard mask layer;

130. a second hard mask layer;

150' a patterned third hard mask layer;

150' mandrel;

152. a first side wall;

130' a patterned second hard mask layer;

132. a second side wall;

110' a patterned first hard mask layer;

250"-1 first mandrel;

250"-2 second mandrel;

250' graphical sixth hard mask layer;

230. a fifth hard mask layer;

252. a third side wall;

230' a patterned fifth hard mask layer;

210. a fourth hard mask layer;

232. a fourth side wall;

210' a fourth patterned hard mask layer;

200. a second material layer to be etched;

201. fin portion

A first trench;

beta second groove;

a gamma third trench;

151. a first layer of sidewall material;

140. a sacrificial layer;

140' patterned sacrificial layer.

Detailed Description

The embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

In the process of forming the target pattern by using the multiple pattern technology, since the intermediate pattern needs to be transferred for multiple times, it is difficult to ensure that the pattern lines in the finally formed target pattern can be completely the same as the expected lines, and even the obtained product may be unqualified due to a large difference.

In order to monitor the process of forming a target pattern by using a multiple pattern technology and the formed target pattern, the disclosure provides a method for forming a monitoring pattern, which distinguishes different mandrels on a mask layer by arranging identification points on the mandrels and correspondingly distinguishes pattern lines formed on the basis of the different mandrels. The monitoring graph formed by the method for forming the monitoring graph can monitor each process of forming the target graph by using the multiple graph technology through monitoring different graph lines in the target graph, so that each process of the multiple graph technology can be improved in a targeted manner.

Example one

The present embodiment provides a method for forming a monitor pattern, and fig. 1 is a flowchart illustrating a method for forming a monitor pattern according to an exemplary embodiment of the present disclosure. As shown in fig. 1, the method of the present embodiment may include the following steps S100 to S300.

S100: providing a material layer to be etched, sequentially forming a preset number of hard mask layers on the surface of the material layer to be etched, wherein the finally formed hard mask layer is a patterned hard mask layer, the finally formed hard mask layer comprises a plurality of mandrels, the mandrels are parallel to each other, and the length of at least one mandrel in the direction in which the mandrels are parallel to each other is different from that of other mandrels.

S200: and forming a side wall positioned around the patterned hard mask layer, then removing the patterned hard mask layer, etching the hard mask layer adjacent to the bottom of the side wall by taking the side wall as a mask, and then removing the side wall to form a new patterned hard mask layer.

S300: repeating the process for forming the patterned hard mask layer for several times to form a monitoring pattern on the hard mask layer adjacent to the material layer to be etched, and then transferring the monitoring pattern to the material layer to be etched.

In the process of forming the monitoring pattern by using the method of the embodiment, at least one mandrel is different from other mandrels in the direction in which the mandrels are parallel to each other, that is, at least one group of two adjacent mandrels is different in length in the direction in which the mandrels are parallel to each other, so that at least one group of two adjacent pattern lines is different in length from each other in the parallel pattern lines in the formed monitoring pattern.

The material layer to be etched is used for forming a multi-pattern having a complex structure, such as a double pattern, a quadruple pattern, a six-fold pattern, and the like, and the disclosure is not particularly limited thereto.

The material layer to be etched can be a semiconductor substrate, the semiconductor substrate can be a silicon substrate or a silicon-on-insulator substrate, and the semiconductor substrate can also be a germanium substrate, a silicon-germanium substrate, a gallium arsenide substrate or a germanium-on-insulator substrate. The material layer to be etched can also be one or more of a silicon oxide layer, a silicon nitride layer, a polycrystalline silicon layer, a low dielectric constant material layer, a high dielectric constant material layer, an amorphous carbon layer and a metal layer.

The process for forming the hard mask layer may include chemical vapor deposition, physical vapor deposition, atomic layer deposition, and the like, and the processes for forming the hard mask layers may be the same or different. The number of the preset layers for forming the hard mask layer on the material layer to be etched may be specifically set according to the needs, and may be, for example, 1 layer, 3 layers, 4 layers, and the like. There may not be a necessary correspondence between the number of layers of the hard mask layer and the number of times of the multiple patterning technique, for example, when a pattern is formed by using the quadruple patterning technique, 3 hard mask layers may be formed, or 4 hard mask layers may be formed, and those skilled in the art may specifically set the number of layers as needed. The hard mask layer may be made of silicon oxide, silicon nitride, silicon oxynitride, carbon, titanium nitride, or tantalum nitride, and the hard mask layers may be made of the same material or different materials.

The process of removing the patterned hard mask layer and the process of removing the sidewall spacers may each include dry etching and/or wet etching. The process of etching the hard mask layer adjacent to the bottom of the sidewall may include dry etching and/or wet etching. The etching process can be selected as desired by those skilled in the art.

The hard mask layer adjacent to the bottom of the side wall is the next hard mask layer adjacent to the hard mask layer where the side wall is located, i.e., to be etched.

The number of times the process of forming the patterned hard mask layer is repeated may be set as desired, for example, it may be repeated 2, 3, or 5 times, etc.

In one embodiment, the process of patterning the finally formed hard mask layer may include: forming a photoetching layer on the finally formed hard mask layer; and photoetching the photoetching layer to form a patterned photoetching layer, etching the finally formed hard mask layer by taking the patterned photoetching layer as a mask, and removing the patterned photoetching layer to form the patterned hard mask layer.

The process for forming the patterned photoresist layer may include uv lithography, 193nm wavelength lithography, and 193nm wavelength immersion lithography, one or more of which may be selected by those skilled in the art as desired, and other processes for patterning the photoresist layer as desired. The process for etching the finally formed hard mask layer can comprise dry etching and wet etching. For example, plasma etching or reactive ion etching may be selected.

In an embodiment, the process of forming the sidewall spacers around the patterned hard mask layer may include: forming a side wall material layer covering the graphical hard mask layer; and etching back the side wall material layer, wherein the side wall material layer positioned around the patterned hard mask layer forms a side wall.

In an embodiment, the process of forming the spacer material layer may include atomic layer deposition. The material of the side wall material layer can be silicon oxide, silicon nitride, silicon oxynitride, carbon, titanium nitride or tantalum nitride.

In an embodiment, the process of etching back the sidewall material layer may include dry etching, for example, reactive ion etching may be selected, and the reactive ion etching has a better directionality.

In an example, the material of the sidewall and the material of the hard mask layer may be different, and the two may have a larger etching selection ratio, for example, the etching selection ratio may be 4:1, 6:1, 10, and the like, so that the etching rates of the sidewall and the hard mask layer are different, which is beneficial to accurately etching off the sidewall material layer on the top of the hard mask layer, forming the sidewall around the patterned hard mask layer, and accurately removing the patterned hard mask layer.

In an embodiment, the width of the sidewall may be in a range of 5 to 20nm, and of course, other dimensions are also possible, which is not specifically limited in this disclosure.

In an embodiment, the method of this embodiment may further include: forming a sacrificial layer between the adjacent hard mask layers; and etching the hard mask layer adjacent to the bottom of the side wall by using the side wall as a mask, and then removing the side wall to form a new graphical hard mask layer, wherein the step of etching the hard mask layer comprises the following steps: etching the sacrificial layer adjacent to the bottom of the side wall by taking the side wall as a mask, and then removing the side wall to form a patterned sacrificial layer; and taking the patterned sacrificial layer as a mask, etching the hard mask layer adjacent to the bottom of the patterned sacrificial layer, and then removing the patterned sacrificial layer to form a new patterned hard mask layer.

The sacrificial layer is arranged between the adjacent hard mask layers, so that the next hard mask layer can be prevented from being damaged when the upper hard mask layer is etched, and the accuracy of pattern transfer is improved.

The process of forming the sacrificial layer may include chemical vapor deposition, physical vapor deposition, atomic layer deposition, and the like. The processes for forming the sacrificial layer and the hard mask layer may be the same or different. In the case where a plurality of sacrificial layers need to be formed, the processes for forming the respective sacrificial layers may be the same or different, and the disclosure is not particularly limited thereto. The material of the sacrificial layer may be silicon oxide, silicon nitride, silicon oxynitride, carbon, titanium nitride, tantalum nitride, or the like. The sacrificial layer may be the same as or different from the hard mask layer. The materials of the adjacent sacrificial layers and the hard mask layer can be the same or different. In one embodiment, the adjacent sacrificial layer and the hard mask layer are made of different materials, and the two materials can have a larger etching selection ratio.

In one embodiment, a sacrificial layer may be disposed between the material layer to be etched and the hard mask layer to reduce damage to the material layer to be etched.

In one embodiment, the material layer to be etched on which the monitor pattern is formed may include 4 times as many fins as the number of mandrels in the arrangement direction of the mandrels.

Example two

The present disclosure provides a pattern monitoring method, wherein a monitoring pattern formed by the method for forming a monitoring pattern may include: acquiring a third distance between two adjacent pattern lines with different lengths in the pattern lines of the monitoring pattern extending in the direction parallel to the mandrel; and judging whether the monitoring graph meets the preset requirement or not according to the third distance.

With the pattern monitoring method of this embodiment, based on the monitoring pattern formed by the above-described method for forming a monitoring pattern, since at least one mandrel has a length in a direction in which the mandrels are parallel to each other that is different from that of the other mandrels, at least one set of two adjacent pattern lines among the pattern lines extending in a direction parallel to the mandrels in the monitoring pattern have lengths different from each other. And determining the distance between the two graphic lines with different lengths as a third distance, so that the graphic lines on two sides of the third distance are distinguished from other graphic lines, and monitoring the process corresponding to the graphic lines on two sides of the third distance and improving the process if necessary can be realized according to whether the third distance meets the preset requirement.

In an embodiment, in case that it is determined that the monitoring pattern does not satisfy the preset requirement according to the third distance, the method further includes: and adjusting the distance between the adjacent mandrels corresponding to the third distance by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the third distance.

And under the condition that the monitoring graph does not meet the preset requirement according to the third distance, the monitoring graph can meet the preset requirement by adjusting the size of the third distance. In an embodiment, the third distance may be adjusted by adjusting a distance between adjacent mandrels corresponding to the third distance, and then the third distance may be adjusted by adjusting a patterning process of the finally formed hard mask layer.

In an embodiment, the graphic monitoring method may further include: acquiring a second distance adjacent to the third distance; judging whether the monitoring pattern meets the preset requirement according to the third distance may include: and judging whether the monitoring graph meets the preset requirement or not according to the second distance and/or the third distance.

After the third distance is determined, a second distance adjacent to the third distance may be further determined based on the position of the third distance, so as to further implement monitoring of the process corresponding to the graphic lines on both sides of the second distance according to whether the second distance and/or the third distance meet the preset requirement.

In an embodiment, in the case that it is determined that the monitoring pattern does not satisfy the preset requirement according to the second distance and/or the third distance, the method further includes: under the condition that the size of the second distance does not meet the preset requirement, adjusting the thickness of the side wall corresponding to the second distance by adjusting the process for forming the side wall corresponding to the second distance so as to realize the adjustment of the second distance; under the condition that the size relation between the second distance and the third distance does not meet the preset requirement: adjusting the thickness of the side wall corresponding to the second distance by adjusting the process of forming the side wall corresponding to the second distance so as to realize the adjustment of the second distance; and/or adjusting the distance between the adjacent mandrels corresponding to the third distance by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the third distance.

Determining that the monitoring pattern does not meet the preset requirement according to the second distance and/or the third distance may include: the size of the second distance does not meet the preset requirement, and the size relationship between the second distance and the third distance does not meet the preset requirement.

Under the condition that the size of the second interval does not meet the preset requirement, the monitoring graph can meet the preset requirement by adjusting the size of the second interval. In an embodiment, the second distance may be adjusted by adjusting the thickness of the sidewall corresponding to the second distance, and then the adjustment of the second distance may be realized by adjusting a process of forming the sidewall corresponding to the second distance.

Under the condition that the size relation between the second distance and the third distance does not meet the preset requirement, the size of the second distance can be adjusted, and the size of the third distance can also be adjusted, so that the monitoring pattern meets the preset requirement. In an embodiment, the second distance may be adjusted by adjusting the thickness of the sidewall corresponding to the second distance, and then the second distance may be adjusted by adjusting a process of forming the sidewall corresponding to the second distance, and/or the third distance may be adjusted by adjusting a distance between adjacent mandrels corresponding to the third distance, and then the third distance may be adjusted by adjusting a patterning process of the finally formed hard mask layer.

In an embodiment, the graphic monitoring method may further include: acquiring a first distance in a direction adjacent to the second distance and far away from the third distance; judging whether the monitoring pattern meets the preset requirement according to the third distance may include: and judging whether the monitoring pattern meets the preset requirement according to at least one of the first spacing, the second spacing and the third spacing.

After the second distance is determined, a first distance which is adjacent to the second distance and is far away from the third distance can be further determined based on the positions of the second distance and the third distance, so that the process corresponding to the graphic lines on the two sides of the first distance can be further monitored according to whether the first distance, the second distance and/or the third distance meet preset requirements.

In an embodiment, in a case that it is determined that the monitor pattern does not satisfy the preset requirement according to at least one of the first pitch, the second pitch, and the third pitch, the method further includes: under the condition that the size of the first interval does not meet the preset requirement, the length of the mandrels corresponding to the first interval in the arrangement direction of each mandrel is adjusted by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the first interval; under the condition that the size relation among the first distance, the second distance and the third distance does not meet the preset requirement; adjusting the lengths of the mandrels corresponding to the first interval in the arrangement direction of the mandrels by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the first interval; and/or adjusting the thickness of the side wall corresponding to the second distance by adjusting the process of forming the side wall corresponding to the second distance so as to adjust the second distance; and/or adjusting the distance between the adjacent mandrels corresponding to the third distance by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the third distance.

Determining that the monitoring pattern does not meet the preset requirement according to at least one of the first pitch, the second pitch and the third pitch may include: the size of the first distance does not meet the preset requirement, and the size relation between the first distance and the second distance and the size relation between the first distance and the third distance do not meet the preset requirement.

Under the condition that the size of the first interval does not meet the preset requirement, the monitoring graph can meet the preset requirement by adjusting the size of the first interval. In an embodiment, the first distance may be adjusted by adjusting the length of the mandrels corresponding to the first distance in the arrangement direction of the mandrels, and then the adjustment of the first distance may be achieved by adjusting the patterning process of the finally formed hard mask layer.

Under the condition that the size relation among the first distance, the second distance and the third distance does not meet the preset requirement, the size of the first distance can be adjusted, the size of the second distance can be adjusted, and the size of the third distance can also be adjusted, so that the monitoring pattern meets the preset requirement. In an embodiment, the size of the first distance may be adjusted by adjusting the lengths of the mandrels corresponding to the first distance in the arrangement direction of the mandrels, and then the adjustment of the first distance may be achieved by adjusting the patterning process of the finally formed hard mask layer, and/or the size of the second distance may be adjusted by adjusting the thickness of the side wall corresponding to the second distance, and then the adjustment of the second distance may be achieved by adjusting the process of forming the side wall corresponding to the second distance, and/or the size of the third distance may be adjusted by adjusting the distance between adjacent mandrels corresponding to the third distance, and then the adjustment of the third distance may be achieved by adjusting the patterning process of the finally formed hard mask layer.

In the case that there are more kinds of pitches between the pattern lines in the monitoring pattern, the method for distinguishing the different pitches may be similar to the above method, and the method for monitoring the corresponding process for forming the pattern lines is similar to the above method, and is not described herein again.

In this embodiment, the preset requirement may be set according to actual needs, for example, the measured distance between the pattern lines is within a preset distance range, the preset distance range is, for example, 9 ± 1nm, or a plurality of distances are equal in size or satisfy a certain specific relationship, and the like.

By using the graph monitoring method, each process of the multiple graph technology can be monitored, so that the process of the multiple graph technology can be improved in a targeted manner, and the yield is improved.

EXAMPLE III

The method of the present disclosure is illustrated in the present embodiment by taking a quad-pattern technique as an example, but the method of the present disclosure is also applicable to a multi-pattern technique with a smaller or greater number of patterns.

Referring to fig. 2A to 2I, a monitoring pattern according to an embodiment of the present disclosure is formed as follows.

A first hard mask layer 110, a second hard mask layer 130 and a patterned third hard mask layer 150 'are formed on the first material layer to be etched 100, wherein the patterned third hard mask layer 150' includes 2 mandrels 150". The first material layer to be etched 100 is a silicon substrate. The first, second and third hard mask layers are formed by chemical vapor deposition, and are made of silicon oxide.

The cross section shown in the figure is a plane perpendicular to the direction in which the mandrels are parallel to each other, and the arrangement direction of the mandrels and the direction in which the mandrels are parallel to each other are perpendicular to each other in the plane in which the hard mask layer is located.

Utilizing the atomic layer deposition technology, forming a first side wall 152 around the patterned third hard mask layer 150', removing the patterned third hard mask layer 150' by using the first side wall 152 as a mask and utilizing the dry etching technology, etching the second hard mask layer 130 by utilizing the dry etching technology, and then removing the first side wall 152 to form the patterned second hard mask layer 130'.

Forming a second side wall 132 around the patterned second hard mask layer 130' by using an atomic layer deposition technique, removing the patterned second hard mask layer 130' by using a dry etching technique with the second side wall 132 as a mask, etching the first hard mask layer 110 by using the dry etching technique, and then removing the second side wall 132 to form a patterned first hard mask layer 110', namely forming a monitoring pattern on the first hard mask layer 110.

Finally, the patterned first hard mask layer 110' is used as a mask, the first material layer to be etched 100 is etched by using a dry etching technology, and the monitoring pattern on the first hard mask layer 110 is transferred to the first material layer to be etched 100.

Referring to fig. 3, in the present embodiment, the length of each mandrel in the arrangement direction of the mandrels determines the width of the first trench α in the monitor pattern (i.e., the distance between two adjacent pattern lines), the thickness of the first sidewall determines the width of the second trench β in the monitor pattern, and the distance between two mandrels determines the width of the third trench γ in the monitor pattern. It can be seen that the different processes in the quad-patterning technique determine the width of the different trenches. With the method of this embodiment, identification points may be provided on the mandrels, for example, different mandrels may be provided with different lengths, or other marks for identification may be provided, so that the grooves formed in different processes may be distinguished based on the identification points. When the width of the formed groove does not meet the preset requirement, each technological process needing to be adjusted can be determined, and the improvement of the technological process of the quadruple pattern technology in a targeted manner is facilitated.

Referring to fig. 4A to 4G, in the patterned sixth hard mask layer 250', the first mandrel 250"-1 and the second mandrel 250" -2 have different lengths.

Forming a third sidewall 252 around the patterned sixth hard mask layer 250', removing the patterned sixth hard mask layer 250' by using the third sidewall 252 as a mask, and etching the fifth hard mask layer 230 adjacent to the bottom of the third sidewall 252 to remove the third sidewall 252 and form a patterned fifth hard mask layer 230'.

Forming a fourth sidewall 232 around the patterned fifth hard mask layer 230', removing the patterned fifth hard mask layer 230' by using the fourth sidewall 232 as a mask, etching the fourth hard mask layer 210 adjacent to the bottom of the fourth sidewall 232, removing the fourth sidewall 232, and forming a patterned fourth hard mask layer 210', i.e., forming a monitoring pattern.

Finally, the monitor pattern is transferred to the second material layer to be etched 200.

As can be seen from the figure, based on the fact that the first mandrel 250"-1 and the second mandrel 250" -2 have different lengths, the lengths of the adjacent sides of the two adjacent annular grooves in the monitoring pattern are different, so that the third groove γ can be identified, the two grooves adjacent to the third groove γ are the second groove β, the groove adjacent to the second groove β on the side of the second groove β far from the third groove γ is the first groove α, and the fin 201 included in the formed monitoring pattern is located between the first groove α and the second groove β and between the second groove β and the third groove γ. When any one of the first, second and third grooves does not meet the preset requirement, the technological process of the quadruple pattern technology can be adjusted in a targeted manner.

For example, referring to fig. 3 and 4G, if the width w3 of the third trench γ is greater than the expected width range, the distance between the corresponding adjacent mandrels can be reduced by adjusting the patterning process of the sixth hard mask layer; if the width w2 of the second trench β is smaller than the expected width range, the thickness of the third sidewall 252 may be increased by adjusting the process for forming the third sidewall 252; the width w2 of the second trench β is not equal to the width w3 of the third trench γ, so that the thickness of the third sidewall 252 may be equal to the distance between corresponding adjacent mandrels by adjusting the patterning process of the sixth hard mask layer and/or the process for forming the third sidewall 252; the width w1 of the first trench α is within the expected width range, which indicates that the lengths of the corresponding mandrels in the arrangement direction of the mandrels satisfy the requirement, i.e., the patterning process of the sixth hard mask layer is suitable.

With reference to fig. 5A to 5C, on the basis of the embodiment shown in fig. 2A to 2I, when forming the first sidewall, a sidewall material layer 151 may be deposited on the patterned third hard mask layer 150' by using an atomic layer deposition technique, and the sidewall material layer 151 is etched back to form a first sidewall 152. Of course, similar processes may be adopted when forming other sidewalls, and are not described herein again.

In the embodiment shown in fig. 2A to 2I, referring to fig. 6A to 6E, a sacrificial layer 140 is formed between the third hard mask layer (not shown) and the second hard mask layer 130.

After the first sidewalls 152 are formed, the patterned third hard mask layer (not shown) is removed by using the first sidewalls 152 as a mask, the sacrificial layer 140 adjacent to the bottom of the first sidewalls 152 is etched, and the first sidewalls 152 are removed to form a patterned sacrificial layer 140'.

And etching the second hard mask layer 130 adjacent to the bottom of the patterned sacrificial layer 140 'by using the patterned sacrificial layer 140' as a mask, and removing the patterned sacrificial layer 140 'to form the patterned second hard mask layer 130'.

Fig. 6A to 6E are merely examples, and a sacrificial layer may be formed as needed, in one embodiment, at least one sacrificial layer may be formed between each adjacent hard mask layer, and in another embodiment, a sacrificial layer may be formed between the first material layer to be etched 100 and the first hard mask layer 110.

Larger etching selection ratios can be set between the sacrificial layer and the adjacent hard mask layer and between the sacrificial layer and the adjacent material layer to be etched, and the sacrificial layer is arranged between the material layer to be etched and the hard mask layer, so that the damage to the material layer to be etched can be reduced.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. When the terms "comprises," "comprising," and/or "made from … …" are used herein, the presence of the stated features, integers, steps, operations, elements, and/or components is specified, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Embodiments of the present disclosure and features of embodiments may be combined with each other without conflict.

Although the terms "first," "second," "third," etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section, and are not used to describe a particular order or sequence. Thus, a first element, component, region, layer or section discussed herein could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure.

Spatial relationship terms, such as "above", "below", "beneath", and the like, may be used herein for convenience of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, then elements or features described as "below" other elements would then be oriented "above" the other elements or features. Thus, the exemplary terms "under" and "under" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Embodiments of the present disclosure are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the present disclosure. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the present disclosure should not be limited to the particular shapes of regions illustrated herein, but are to include deviations in shapes that result, for example, from manufacturing.

The exemplary embodiments herein may be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. Additionally or alternatively, certain steps may be omitted, multiple steps combined into one step execution, and/or one step broken down into multiple step executions. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of these exemplary embodiments to those skilled in the art, and should not be construed as limiting the present disclosure.

While the spirit and principles of the present disclosure have been described with reference to several particular embodiments, it is to be understood that the present disclosure is not limited to the particular embodiments disclosed, nor is the division of aspects, which is for convenience only as the features in such aspects may not be combined to benefit. The disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims (13)

1. A method of forming a monitor pattern, comprising:

providing a material layer to be etched, sequentially forming a preset number of hard mask layers on the surface of the material layer to be etched, wherein the finally formed hard mask layer is a graphical hard mask layer, the finally formed hard mask layer comprises a plurality of mandrels, the mandrels are parallel to each other, and the length of at least one mandrel in the direction in which the mandrels are parallel to each other is different from that of other mandrels;

forming a side wall positioned around the patterned hard mask layer, then removing the patterned hard mask layer, etching the hard mask layer adjacent to the bottom of the side wall by taking the side wall as a mask, and then removing the side wall to form a new patterned hard mask layer;

repeating the process for forming the patterned hard mask layer for a plurality of times to form a monitoring pattern on the hard mask layer adjacent to the material layer to be etched, and then transferring the monitoring pattern to the material layer to be etched.

2. The method as claimed in claim 1, wherein the step of patterning the hard mask layer comprises:

forming a photoetching layer on the finally formed hard mask layer;

and photoetching the photoetching layer to form a patterned photoetching layer, etching the finally formed hard mask layer by taking the patterned photoetching layer as a mask, and removing the patterned photoetching layer to form the patterned hard mask layer.

3. The method for forming a monitoring pattern according to claim 1, wherein the process for forming the sidewall spacer around the patterned hard mask layer comprises:

forming a side wall material layer covering the graphical hard mask layer;

and etching back the side wall material layer, wherein the side wall material layer positioned around the patterned hard mask layer forms a side wall.

4. The method as claimed in claim 3, wherein the process of forming the spacer material layer comprises atomic layer deposition.

5. The method as claimed in claim 3, wherein the process of etching back the spacer material layer comprises dry etching.

6. The method for forming a monitor pattern according to claim 1, further comprising: forming a sacrificial layer between the adjacent hard mask layers;

etching the hard mask layer adjacent to the bottom of the side wall by using the side wall as a mask, and then removing the side wall to form a new graphical hard mask layer, wherein the step of etching the hard mask layer comprises the following steps:

etching the sacrificial layer adjacent to the bottom of the side wall by taking the side wall as a mask, and then removing the side wall to form a patterned sacrificial layer;

and etching the hard mask layer adjacent to the bottom of the patterned sacrificial layer by taking the patterned sacrificial layer as a mask, and then removing the patterned sacrificial layer to form a new patterned hard mask layer.

7. The method as claimed in claim 1, wherein the material layer to be etched on which the monitor pattern is formed includes fins 4 times as many as the number of the mandrels in the arrangement direction of the mandrels.

8. A pattern monitoring method, wherein a monitor pattern formed based on the monitor pattern forming method according to any one of claims 1 to 7, comprises:

acquiring a third distance between two adjacent pattern lines with different lengths in the pattern lines of the monitoring pattern extending in the direction parallel to the mandrel;

and judging whether the monitoring graph meets a preset requirement or not according to the third distance.

9. The pattern monitoring method according to claim 8, wherein in a case where it is determined that the monitoring pattern does not satisfy a preset requirement according to the third pitch, the method further comprises:

and adjusting the distance between the adjacent mandrels corresponding to the third distance by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the third distance.

10. The pattern monitoring method according to claim 8, further comprising:

acquiring a second distance adjacent to the third distance;

judging whether the monitoring graph meets a preset requirement according to the third distance, comprising the following steps:

and judging whether the monitoring graph meets a preset requirement or not according to the second distance and/or the third distance.

11. The pattern monitoring method according to claim 10, wherein in a case where it is determined from the second pitch and/or the third pitch that the monitored pattern does not satisfy a preset requirement, the method further comprises:

under the condition that the size of the second interval does not meet the preset requirement, adjusting the thickness of the side wall corresponding to the second interval by adjusting the process for forming the side wall corresponding to the second interval so as to realize the adjustment of the second interval;

under the condition that the size relation between the second distance and the third distance does not meet the preset requirement:

adjusting the thickness of the side wall corresponding to the second distance by adjusting the process of forming the side wall corresponding to the second distance so as to adjust the second distance; and/or the presence of a gas in the atmosphere,

and adjusting the distance between the adjacent mandrels corresponding to the third distance by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the third distance.

12. The pattern monitoring method according to claim 10, further comprising:

acquiring a first distance in a direction adjacent to the second distance and away from the third distance;

judging whether the monitoring graph meets a preset requirement according to the third distance, comprising the following steps:

and judging whether the monitoring graph meets a preset requirement according to at least one of the first spacing, the second spacing and the third spacing.

13. The pattern monitoring method according to claim 12, wherein in a case where it is determined that the monitoring pattern does not satisfy a preset requirement according to at least one of the first pitch, the second pitch, and the third pitch, the method further comprises:

under the condition that the size of the first interval does not meet the preset requirement, the length of the mandrels corresponding to the first interval in each mandrel arrangement direction is adjusted by adjusting the patterning process of the finally formed hard mask layer, so that the adjustment of the first interval is realized;

under the condition that the size relation among the first distance, the second distance and the third distance does not meet the preset requirement;

adjusting the lengths of the mandrels corresponding to the first interval in the arrangement direction of the mandrels by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the first interval; and/or the presence of a gas in the gas,

adjusting the thickness of the side wall corresponding to the second distance by adjusting the process of forming the side wall corresponding to the second distance so as to adjust the second distance; and/or the presence of a gas in the gas,

and adjusting the distance between the adjacent mandrels corresponding to the third distance by adjusting the patterning process of the finally formed hard mask layer so as to realize the adjustment of the third distance.

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