阅读说明：本技术 光刻条件的在线监测方法及掩膜版 (Online monitoring method for photoetching conditions and mask ) 是由 杨红美 金佩 李伟峰 顾以理 于 2021-07-07 设计创作，主要内容包括：本申请公开了一种光刻条件的在线监测方法及掩膜版,涉及半导体制造领域。该光刻条件的在线监测方法包括通过光刻工艺在晶圆表面形成CD Bar和若干条状辅助结构；监测所述CD Bar的尺寸和形貌；其中,所述条状辅助结构位于所述CD Bar的四周；解决了目前在图形密度过低的层侧容易发生CD Bar区域倒胶的问题；达到了改善CD Bar区域倒胶,提高光刻条件监测结果的准确性的稳定性的效果。(The application discloses an online monitoring method of photoetching conditions and a mask, and relates to the field of semiconductor manufacturing. The online monitoring method of the photoetching conditions comprises the steps of forming CD Bar and a plurality of strip-shaped auxiliary structures on the surface of a wafer through a photoetching process; monitoring the size and morphology of the CD Bar; wherein the strip-shaped auxiliary structure is positioned around the CD Bar; the problem that the CD Bar area is easy to be glued on the layer side with too low graph density at present is solved; the effects of improving the CD Bar area glue pouring and improving the stability of the accuracy of the photoetching condition monitoring result are achieved.)

1. A method of on-line monitoring of lithography conditions, the method comprising:

forming CD Bar and a plurality of strip-shaped auxiliary structures on the surface of the wafer through a photoetching process;

monitoring the size and morphology of the CD Bar;

wherein the strip-shaped auxiliary structure is positioned around the CD Bar.

2. The method as claimed in claim 1, wherein the forming of the CD Bar and the plurality of strip-shaped auxiliary structures on the wafer surface by the photolithography process comprises:

and forming the CD Bar and the plurality of strip-shaped auxiliary structures on the surface of the cutting channel of the wafer through a photoetching process.

3. The method according to claim 1 or 2, wherein a part of the strip-shaped auxiliary structure is perpendicular to the cutting street, and the length of the strip-shaped auxiliary structure perpendicular to the cutting street is smaller than the width of the cutting street;

and part of the strip-shaped auxiliary structures are parallel to the cutting channels.

4. The method according to claim 1 or 2, wherein the width of the stripe-like auxiliary structure is not less than the width of the CD Bar.

5. A method according to claim 1 or 2, characterized in that a reticle comprising a CD Bar pattern and a stripe-like auxiliary structure pattern is used when performing the lithography process.

6. A mask is characterized by comprising a CD Bar pattern and a plurality of strip-shaped auxiliary structure patterns;

wherein the strip-shaped auxiliary structure pattern is positioned around the CD Bar pattern.

7. The reticle of claim 6, wherein the width of the stripe-shaped auxiliary structure pattern is not less than the width of the CD Bar pattern.

8. The reticle of claim 6 or 7, wherein a portion of the stripe-shaped auxiliary structure pattern is parallel to an X direction of the CD Bar pattern and a portion of the stripe-shaped auxiliary structure pattern is parallel to a Y direction of the CD Bar pattern.

Technical Field

The application relates to the field of semiconductor manufacturing, in particular to an online monitoring method of photoetching conditions and a mask.

Background

In semiconductor manufacturing, online (inline) monitoring of lithography conditions is mainly achieved by measuring critical dimensions in one direction of a monitored pattern. At present, the CD Bar shown in fig. 1 is used as a monitored pattern, and the CD Bar is measured to ensure the normal formation of the lithography pattern and provide an important basis for ensuring the yield and stability of the product.

For the layer with too low pattern density, the pattern is represented by too few light transmission areas on the mask, generally, the light transmission rate on the mask is lower than 0.3%, the patterns formed by photoetching are few and isolated, and the periphery of the CD Bar for online monitoring is very spacious. During developing, under the rotation action of the wafer, the flow velocity of the developing solution around the CD Bar is accelerated to increase the impact force, and the CD Bar is easy to fall under the strong impact action of the developing solution.

The phenomenon of photoresist falling in a CD Bar area caused by too low pattern density can be improved by adjusting the developing rotating speed, but the problems of poor development and the like can be caused by adjusting the developing rotating speed.

Disclosure of Invention

In order to solve the problems in the related art, the application provides an online monitoring method of photoetching conditions and a mask. The technical scheme is as follows:

in a first aspect, an embodiment of the present application provides an online monitoring method for lithography conditions, including:

forming CD Bar and a plurality of strip-shaped auxiliary structures on the surface of the wafer through a photoetching process;

monitoring the size and morphology of the CD Bar;

wherein, the strip-shaped auxiliary structure is positioned at the periphery of the CD Bar.

Optionally, forming CD Bar and a plurality of strip-shaped auxiliary structures on the surface of the wafer by a photolithography process, including:

and forming the CD Bar and a plurality of strip-shaped auxiliary structures on the surface of the cutting channel of the wafer through a photoetching process.

Optionally, a part of the strip-shaped auxiliary structure is perpendicular to the cutting street, and the length of the strip-shaped auxiliary structure perpendicular to the cutting street is smaller than the width of the cutting street;

part of the strip-shaped auxiliary structure is parallel to the cutting path.

Optionally, the width of the strip-shaped auxiliary structure is not less than the width of the CD Bar.

Optionally, when performing the photolithography process, a mask including a CD Bar pattern and a stripe-shaped auxiliary structure pattern is used.

In a second aspect, an embodiment of the present application provides a mask, where the mask includes a CD Bar pattern and a plurality of strip-shaped auxiliary structure patterns;

wherein, the strip-shaped auxiliary structure pattern is positioned at the periphery of the CD Bar pattern.

Optionally, the width of the stripe-shaped auxiliary structure pattern is not less than the width of the CD Bar pattern.

Optionally, a part of the strip-shaped auxiliary structure pattern is parallel to the X direction of the CD Bar pattern, and a part of the strip-shaped auxiliary structure pattern is parallel to the Y direction of the CD Bar pattern.

The technical scheme at least comprises the following advantages:

forming a CD Bar and a plurality of strip-shaped auxiliary structures positioned around the CD Bar on the surface of the wafer through a photoetching process, and monitoring the size and the shape of the CD Bar; the problem that the CD Bar area is easy to be glued on the layer side with too low graph density at present is solved; the effects of improving the CD Bar area glue pouring and improving the stability of the accuracy of the photoetching condition monitoring result are achieved.

Drawings

In order to more clearly illustrate the detailed description of the present application or the technical solutions in the prior art, the drawings needed to be used in the detailed description of the present application or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic view of a CD Bar;

FIG. 2 is a flowchart of a method for on-line monitoring of lithography conditions according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a CD Bar, special mark, code

FIG. 4 is a schematic diagram of a CD Bar and stripe assistant structure provided in an embodiment of the present application;

FIG. 5 is a schematic diagram of the size and morphology of CD Bar measured by SEM according to an embodiment of the present application;

FIG. 6 is a schematic diagram of another CD Bar and stripe assistant structure provided in the embodiments of the present application;

FIG. 7 is a schematic diagram of another CD Bar and stripe assistant structure provided in the embodiments of the present application;

FIG. 8 is a schematic diagram of another CD Bar and stripe assistant structure provided in the embodiments of the present application;

fig. 9 is a schematic diagram of the size and morphology of CD Bar measured by SEM according to another embodiment of the present application.

Detailed Description

The technical solutions in the present application will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the connection can be mechanical connection or electrical connection; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

In addition, the technical features mentioned in the different embodiments of the present application described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 2, a flowchart of an on-line monitoring method for lithography conditions according to an embodiment of the present application is shown, the method at least includes the following steps:

step 101, forming a CD Bar and a plurality of strip-shaped auxiliary structures on the surface of a wafer through a photoetching process.

Coating photoresist on the surface of a wafer needing a photoetching process, exposing by using a mask plate, and forming a preset structure for forming a product, a CD Bar and a plurality of strip-shaped auxiliary structures for online monitoring on the surface of the wafer after developing.

The strip-shaped auxiliary structure is positioned at the periphery of the CD Bar.

As shown in fig. 3, the CD BAR 21 has both a horizontal metrology pattern, a vertical metrology pattern, a dense metrology pattern, a semi-dense metrology pattern and an isolated metrology pattern. Special marks 23 for positioning and automatic focusing and a code 24 for identifying the CD Bar are also formed near the CD Bar 21.

In one example, as shown in fig. 4, the CD Bar is surrounded by 4 strip-like auxiliary structures 22.

When the photoetching process is carried out, the mask used comprises a CD Bar pattern and a strip-shaped auxiliary structure pattern. In the normal developing process, the developing solution can firstly dissolve the photoresistance in the pattern region of the strip-shaped auxiliary structure, when the developing solution flows to the CD Bar pattern region, the washing speed of the developing solution is slowed down, the impact force is obviously reduced, and the phenomenon of glue falling of the photoresistance in the CD Bar pattern region can not occur.

Step 102, monitoring the size and morphology of the CD Bar.

The dimension and the morphology of the CD Bar are monitored by a CD measuring machine.

Alternatively, the size and morphology of CD Bar is monitored by Scanning Electron Microscopy (SEM).

In an example, the photolithography is performed to form a stripe-shaped auxiliary structure as shown in fig. 4, the dimension and the profile of the CD Bar measured by an electron scanning electron microscope are shown in fig. 5, and the dimension and the profile of the CD Bar can be accurately obtained without occurrence of glue collapse of the CD Bar.

In summary, in the online monitoring method for the lithography conditions provided in the embodiment of the present application, the CD Bar and the plurality of strip-shaped auxiliary structures located around the CD Bar are formed on the surface of the wafer through the lithography process, and the size and the shape of the CD Bar are monitored; the environment around the CD Bar is improved through the strip-shaped auxiliary structure, the CD Bar is protected during development, and the problem that the CD Bar area is easy to be subjected to glue pouring on the layer side with too low pattern density at present is solved; the effects of improving the CD Bar area glue pouring and improving the stability of the accuracy of the photoetching condition monitoring result are achieved.

In an alternative embodiment based on the embodiment shown in fig. 1, in order to prevent the CD Bar from affecting the device structure and performance, the CD Bar and a plurality of strip-shaped auxiliary structures are formed in the scribe lines of the wafer. That is, the step 101, that is, the step of "forming CD Bar and a plurality of strip-shaped auxiliary structures on the surface of the wafer by using the photolithography process", may be implemented by the following steps:

in step 1011, CD Bar and a plurality of strip-shaped auxiliary structures are formed on the surface of the scribe line of the wafer by the photolithography process.

When the mask is used for exposure, the CD Bar pattern and the strip-shaped auxiliary structure pattern on the mask are aligned to the cutting path area on the wafer.

In an alternative embodiment based on the embodiment shown in fig. 1, a part of the strip-shaped auxiliary structures is perpendicular to the scribe lines on the wafer, and the length of the strip-shaped auxiliary structures perpendicular to the scribe lines is smaller than the width of the scribe lines; part of the strip-shaped auxiliary structure is parallel to the cutting channels on the wafer; the length of the strip-shaped auxiliary structure parallel to the cutting line is not limited.

The CD Bar and the strip-shaped auxiliary structures around the CD Bar are both positioned in the cutting path area on the wafer.

In an alternative embodiment based on the embodiment shown in fig. 1, the width of the stripe-shaped auxiliary structure is not smaller than the width of the CD Bar.

It should be noted that the number of the strip-shaped auxiliary structures in the X direction of the CD Bar may be the same as or different from the number of the strip-shaped auxiliary structures in the Y direction of the CD Bar; the lengths of the strip-shaped auxiliary structures around the CD Bar are the same or different, and the widths of the strip-shaped auxiliary structures around the CD Bar are the same or different; the number of the strip-shaped auxiliary structures on each side of the CD Bar is one or more, and the number of the strip-shaped auxiliary structures on each side of the CD Bar can be the same or different; the strip-shaped auxiliary structures may or may not be in contact with each other.

Fig. 6 shows a schematic diagram of a CD Bar and a stripe-shaped auxiliary structure, fig. 7 shows a schematic diagram of another CD Bar and a stripe-shaped auxiliary structure, and fig. 8 shows a schematic diagram of another CD Bar and a stripe-shaped auxiliary structure. It should be noted that fig. 4, 6, 7, and 8 are only exemplary illustrations, and the relationship between the CD Bar and the stripe-shaped auxiliary structure is not limited.

In another example, the photolithographic stripe-shaped auxiliary structure is shown in fig. 7, the dimension and the profile of the CD Bar measured by an electron scanning electron microscope are shown in fig. 9, the CD Bar is not subjected to glue falling, and the dimension and the profile of the CD Bar can be accurately obtained.

The embodiment of the application also provides a mask which can be used in the online monitoring method of the photoetching conditions, and the mask comprises a CD Bar pattern and a plurality of strip-shaped auxiliary structure patterns, wherein the strip-shaped auxiliary structure patterns are positioned around the CD Bar pattern.

Optionally, if the mask of the layer does not include the strip-shaped auxiliary structure pattern, the light transmittance of the mask is smaller than a predetermined value, for example, the predetermined value is 0.3%.

Optionally, on the mask, the width of the strip-shaped auxiliary structure pattern is not less than the width of the CD Bar pattern.

After photoetching is carried out by using the mask, the width of the strip-shaped auxiliary structure formed on the surface of the wafer is not less than the width of the CD Bar.

Optionally, after the mask is used for photolithography, the formed strip-shaped auxiliary structure and the CD Bar are located on the surface of the scribe line of the wafer.

Optionally, on the mask, a part of the strip-shaped auxiliary structure pattern is parallel to the X direction of the CD Bar pattern, and a part of the strip-shaped auxiliary structure pattern is parallel to the Y direction of the CD Bar pattern.

After photoetching is carried out by using the mask, the part of the strip-shaped auxiliary structure in the cutting channel area of the wafer is parallel to the cutting channel, the part of the strip-shaped auxiliary structure is vertical to the cutting channel, and the length of the strip-shaped auxiliary structure vertical to the cutting channel is smaller than the width of the cutting channel.

It should be noted that, on the mask, the number of the strip-shaped auxiliary structure patterns in the X direction of the CD Bar pattern may be the same as or different from the number of the strip-shaped auxiliary structure patterns in the Y direction of the CD Bar pattern; the lengths of the strip-shaped auxiliary structure patterns around the CD Bar pattern are the same or different, and the widths of the strip-shaped auxiliary structure patterns around the CD Bar pattern are the same or different; the number of the strip-shaped auxiliary structure patterns on each side of the CD Bar pattern is one or more, and the number of the strip-shaped auxiliary structure patterns on each side of the CD Bar pattern can be the same or different; the strip-shaped auxiliary structure patterns may or may not be in contact with each other.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of this invention are intended to be covered by the scope of the invention as expressed herein.