Critical dimension monitoring mark structure
By designing a key dimensional monitoring marking structure with gradient changes, the problem that the prior art cannot effectively monitor other actual dimensional change laws in the wafer plane is solved, and the monitoring and determination of the optimal lithography conditions are achieved.
Patent Information
- Application Number
- CN202420666055.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-02
- Publication Date
- 2025-04-15
- Estimated Expiration
- 2034-04-02
AI Technical Summary
The existing key size monitoring marking structure cannot effectively monitor the variation patterns of other actual dimensions in the wafer plane, especially when the CD no longer changes after the light diffraction reaches the maximum.
A critical dimension monitoring mark structure is designed, including a plurality of critical dimension monitoring marks extending in the first direction and arranged in the second direction. The structure includes a dense area and a sparse area, a dense area or a CD of the critical dimension monitoring mark in the sparse area in the first direction with a gradient change.
The CD gradient monitors the possible situation where the CD does not change with energy, and can simultaneously monitor whether the CD gradient has the same change pattern, thereby determining the best lithography conditions and achieving the purpose of effectively monitoring the real changes in the CD in the wafer plane.
Smart Images
Figure CN222762930U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of semiconductor device manufacturing, in particular to a key dimension monitoring mark structure. Background Art
[0002] In semiconductor manufacturing, inline monitoring of photolithography conditions is mainly achieved by measuring the critical dimension of a certain direction of the monitored pattern. Figure 1 The key dimension monitoring mark (or critical dimension monitoring mark, CD Bar) structure shown is used as the monitored pattern. By measuring the key dimension monitoring mark, the normal formation of the lithography pattern can be guaranteed, which is also an important basis for ensuring product yield and stability.
[0003] Currently, the change of the minimum dimension within the wafer surface is monitored through the key dimension monitoring mark. However, after the small-size light diffraction reaches the maximum level, the CD no longer changes with the increase of energy. The change pattern of the existing key dimension monitoring mark size cannot reflect the change pattern of other actual dimensions within the wafer surface. Utility Model Content
[0004] The utility model aims to provide a critical dimension monitoring mark structure, whose CD has a gradient change, so as to monitor the possible situation that the CD no longer changes with energy, and can simultaneously monitor whether the CD gradient has the same change law, so as to determine the best lithography conditions.
[0005] In order to solve the above technical problems, the utility model provides a key dimension monitoring mark structure, including multiple key dimension monitoring marks extending along a first direction and arranged along a second direction, the key dimension monitoring mark structure includes a dense area and a sparse area in the first direction, and the CD of the key dimension monitoring mark in the dense area and / or the sparse area has a gradient change.
[0006] Optionally, in a direction from the dense area to the sparse area, the CD of the critical dimension monitoring mark shows a gradient increasing trend.
[0007] Optionally, the dense area includes a first dense area and a second dense area, the second dense area is located between the first dense area and the sparse area, and the density of the key dimension monitoring mark in the first dense area is greater than the density of the key dimension monitoring mark in the second dense area.
[0008] Optionally, the key dimension monitoring mark includes three lengths, the length of the first key dimension monitoring mark is smaller than the length of the second key dimension monitoring mark, and the length of the second key dimension monitoring mark is smaller than the length of the third key dimension monitoring mark; the first key dimension monitoring mark is located in the first dense area, the second key dimension monitoring mark is located in the first dense area and the second dense area, and the third key dimension monitoring mark is located in the first dense area, the second dense area and the sparse area.
[0009] Optionally, in the first dense area, CDs of the first critical dimension monitoring mark, the second critical dimension monitoring mark and the third critical dimension monitoring mark are the same.
[0010] Optionally, the key dimension monitoring mark structure includes a third key dimension monitoring mark, and the third key dimension monitoring mark is located in the middle position of the first dense area and the second dense area, so that the first dense area and the second dense area both form a vertically symmetrical structure with the third key dimension monitoring mark as the symmetry axis.
[0011] Optionally, in the first dense area, the first critical dimension monitoring mark and the second critical dimension monitoring mark are alternately arranged in the second direction; and the CD of the third critical dimension monitoring mark in the sparse area has a gradient change.
[0012] Optionally, in the first dense area, two of the first critical dimension monitoring marks are arranged between adjacent second critical dimension monitoring marks, and one of the first critical dimension monitoring marks is arranged between the second critical dimension monitoring mark and the third critical dimension monitoring mark; the CD of the second critical dimension monitoring mark in the second dense area has a gradient change.
[0013] Optionally, within the second dense area, the critical dimension monitoring mark structure further includes a fourth critical dimension monitoring mark, wherein the fourth critical dimension monitoring mark is located between adjacent second critical dimension monitoring marks and is close to the first critical dimension monitoring mark.
[0014] Optionally, the CD of the second critical dimension monitoring mark in the second dense area has a gradient change, and the CD of the third critical dimension monitoring mark in the sparse area has a gradient change.
[0015] Compared with the prior art, the key dimension monitoring mark structure provided by the utility model includes a plurality of key dimension monitoring marks extending along the first direction and arranged along the second direction, and the key dimension monitoring mark structure includes a dense area and a sparse area in the first direction, and the CD of the key dimension monitoring mark in the dense area or / and the sparse area has a gradient change. The utility model designs the CD gradient to monitor the possible situation that the CD no longer changes with energy, and can simultaneously monitor whether the CD gradient has the same change law, so as to determine the best lithography conditions, and achieve the purpose of effectively monitoring the real change of CD in the wafer surface. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Those skilled in the art will appreciate that the drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.
[0017] Figure 1 It is a schematic diagram of a key dimension monitoring mark structure in the prior art.
[0018] Figure 2 It is a schematic diagram of the key dimension monitoring mark structure provided in the first embodiment of the present utility model.
[0019] Figure 3 It is a schematic diagram of the key dimension monitoring mark structure provided in the second embodiment of the present utility model.
[0020] Figure 4 It is a schematic diagram of the key dimension monitoring mark structure provided in the third embodiment of the present utility model.
[0021] Description of reference numerals:
[0022] 10-first critical dimension monitoring mark; 20-second critical dimension monitoring mark; 30-third critical dimension monitoring mark; 40-fourth critical dimension monitoring mark; A-dense area; A1-first dense area; A2-second dense area; B-sparse area. DETAILED DESCRIPTION
[0023] In order to make the purpose, advantages and features of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.
[0024] As used in the present invention, the singular forms "one", "an", and "the" include plural objects, unless the content clearly indicates otherwise. As used in the present invention, the term "or" is generally used in a sense that includes "and / or", unless the content clearly indicates otherwise. As used in the present invention, the term "several" is generally used in a sense that includes "at least one", unless the content clearly indicates otherwise. As used in the present invention, the term "at least two" is generally used in a sense that includes "two or more", unless the content clearly indicates otherwise. In addition, the terms "first", "second", and "third" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features.
[0025] The utility model provides a key dimension monitoring mark structure, comprising a plurality of key dimension monitoring marks extending along a first direction and arranged along a second direction, wherein the key dimension monitoring mark structure comprises a dense area and a sparse area in the first direction, and the CD of the key dimension monitoring mark in the dense area and / or the sparse area has a gradient change.
[0026] The CD of the critical dimension monitoring mark has a gradient change. The CD gradient is used to monitor the possible situation where the CD no longer changes with energy. At the same time, it can be monitored whether the CD gradient has the same change law, so as to determine the optimal lithography conditions and achieve the purpose of effectively monitoring the actual change of CD within the wafer surface.
[0027] In one embodiment of the present invention, in the direction from the dense area to the sparse area, the CD of the critical dimension monitoring mark increases gradually, that is, the CD of the critical dimension monitoring mark increases gradually. But it is not limited thereto.
[0028] The dense area and the sparse area are relative. The dense area refers to the area where the key size monitoring marks are arranged densely, and the sparse area refers to the area where the key size monitoring marks are arranged sparsely. The CD of the key size monitoring mark refers to the CD of the key size monitoring mark in the second direction.
[0029] The key dimension monitoring mark structure of the present invention is introduced below through specific embodiments.
[0030] [Example 1]
[0031] Figure 2 This is a schematic diagram of the key dimension monitoring marking structure provided by the first embodiment of the present invention. Figure 2As shown, the critical dimension monitoring mark structure includes a plurality of critical dimension monitoring marks extending along a first direction X and arranged along a second direction Y. The critical dimension monitoring mark structure includes a dense area A and a sparse area B in the first direction X. The CD of the critical dimension monitoring mark in the sparse area B has a gradient change.
[0032] In an embodiment of the present invention, the first direction X and the second direction Y are perpendicular to each other.
[0033] The dense area A includes a first dense area A1 and a second dense area A2, wherein the second dense area A2 is located between the first dense area A1 and the sparse area B, and the density of the key size monitoring marks in the first dense area A1 is greater than the density of the key size monitoring marks in the second dense area A2, that is, the arrangement of the key size monitoring marks in the first dense area A1 is denser than the arrangement of the key size monitoring marks in the second dense area A2. From the first dense area A1 to the sparse area B, the arrangement density of the key size monitoring marks decreases.
[0034] The critical dimension monitoring mark includes three lengths, the length of the first critical dimension monitoring mark 10 is smaller than the length of the second critical dimension monitoring mark 20, and the length of the second critical dimension monitoring mark 20 is smaller than the length of the third critical dimension monitoring mark 30; the first critical dimension monitoring mark 10 is located in the first dense area A1, the second critical dimension monitoring mark 20 is located in the first dense area A1 and the second dense area A2, that is, the second critical dimension monitoring mark 20 extends from the first dense area A1 to the second dense area A2, and the third critical dimension monitoring mark 30 is located in the first dense area A1, the second dense area A2 and the sparse area B, that is, the third critical dimension monitoring mark 30 extends from the first dense area A1 to the sparse area B.
[0035] In this embodiment, in the first dense area A1, the CDs of the first critical dimension monitoring mark 10, the second critical dimension monitoring mark 20 and the third critical dimension monitoring mark 30 are the same, and the spacing between adjacent critical dimension monitoring marks may also be the same, but is not limited thereto.
[0036] The key dimension monitoring mark structure includes a third key dimension monitoring mark 30, and the third key dimension monitoring mark 30 is respectively located in the middle position of the first dense area A1 and the second dense area A2, so that the first dense area A1 and the second dense area A2 both form a vertically symmetrical structure with the third key dimension monitoring mark 30 as the symmetry axis.
[0037] In the first dense area A1, the first critical dimension monitoring marks 10 and the second critical dimension monitoring marks 20 are arranged alternately in the second direction Y. In this embodiment, there are three second critical dimension monitoring marks 20 and three first critical dimension monitoring marks 10 above the third critical dimension monitoring mark 30, and there are three first critical dimension monitoring marks 10 and three second critical dimension monitoring marks 20 below the third critical dimension monitoring mark 30, and the first critical dimension monitoring marks 10 and the second critical dimension monitoring marks 20 are arranged alternately.
[0038] In this embodiment, the CD of the third critical dimension monitoring mark 30 in the sparse area B has a gradient change. The third critical dimension monitoring mark 30 extends from the first dense area A1 to the sparse area B. When entering the sparse area B, the CD of the third critical dimension monitoring mark 30 shows a gradient increase trend, that is, the CD of the third critical dimension monitoring mark 30 gradually increases, and the increased CD may be the same or different.
[0039] The CD of the third CD monitoring mark 30 in the first dense area A1 and the second dense area A2 is the same. The CD of the second CD monitoring mark 20 in the first dense area A1 and the second dense area A2 is also the same.
[0040] In this embodiment, the CD gradient of the third critical dimension monitoring mark 30 in the sparse area B is designed to monitor the possible situation where the CD no longer changes with energy, and at the same time, it can be monitored whether the CD gradient has the same change law, so as to determine the optimal lithography conditions and achieve the purpose of effectively monitoring the actual change of CD in the wafer surface.
[0041] [Example 2]
[0042] The difference between this embodiment and the first embodiment is that the CD of the second critical dimension monitoring mark 20 in the second dense area A2 has a gradient change.
[0043] Figure 3 This is a schematic diagram of the key dimension monitoring marking structure provided by the second embodiment of the present utility model. Figure 3 As shown, in the first dense area A1, two of the first critical dimension monitoring marks 10 are arranged between adjacent second critical dimension monitoring marks 20, and one of the first critical dimension monitoring marks 10 is arranged between the second critical dimension monitoring mark 20 and the third critical dimension monitoring mark 30; the CD of the second critical dimension monitoring mark 20 in the second dense area A2 has a gradient change.
[0044] In the first dense area A1, the CDs of the first critical dimension monitoring mark 10, the second critical dimension monitoring mark 20 and the third critical dimension monitoring mark 30 are the same, and their adjacent intervals are also the same. The third critical dimension monitoring mark 30 extends from the first dense area A1 to the sparse area B, and its CD remains unchanged. The second critical dimension monitoring mark 20 extends from the first dense area A1 to the second dense area A2, and its CD increases in a gradient manner in the second dense area A2, that is, the CD of the second critical dimension monitoring mark 20 gradually increases, and its increased CD can be the same or different.
[0045] In this embodiment, in the second dense area A2, the critical dimension monitoring mark structure further includes a fourth critical dimension monitoring mark 40, and the fourth critical dimension monitoring mark 40 is located between adjacent second critical dimension monitoring marks 20, and the fourth critical dimension monitoring mark 40 is close to the first critical dimension monitoring mark 10. Since the CD of the second critical dimension monitoring mark 20 in the direction from the first dense area A1 to the sparse area B shows a gradient increasing trend in the second dense area A2, the fourth critical dimension monitoring mark 40 is located close to the first dense area A1.
[0046] In this embodiment, the CD gradient of the second critical dimension monitoring mark 20 in the second dense area A2 is designed to monitor the possible situation where the CD no longer changes with energy, and at the same time, it can be monitored whether the CD gradient has the same change law, so as to determine the optimal lithography conditions and achieve the purpose of effectively monitoring the actual changes of CD within the wafer surface.
[0047] [Example 3]
[0048] The difference between this embodiment and the second embodiment is that the CD of the second critical dimension monitoring mark 20 in the second dense area A2 has a gradient change, and the CD of the third critical dimension monitoring mark 30 in the sparse area B has a gradient change.
[0049] Figure 4 This is a schematic diagram of the key dimension monitoring marking structure provided by the third embodiment of the present invention. Figure 4As shown, in the first dense area A1, two first critical dimension monitoring marks 10 are arranged between adjacent second critical dimension monitoring marks 20, and one first critical dimension monitoring mark 10 is arranged between the second critical dimension monitoring mark 20 and the third critical dimension monitoring mark 30. In the first dense area A1, a first critical dimension monitoring mark 10, a second critical dimension monitoring mark 20, two first critical dimension monitoring marks 10 and a second critical dimension monitoring mark 20 are arranged in sequence above the third critical dimension monitoring mark 30, and a first critical dimension monitoring mark 10, a second critical dimension monitoring mark 20, two first critical dimension monitoring marks 10 and a second critical dimension monitoring mark 20 are arranged in sequence below the third critical dimension monitoring mark 30. The first dense area A1 forms a vertically symmetrical structure with the third critical dimension monitoring mark 30 as the symmetry axis.
[0050] In the first dense area A1, the CDs of the first critical dimension monitoring mark 10, the second critical dimension monitoring mark 20 and the third critical dimension monitoring mark 30 are the same, and the intervals between adjacent critical dimension monitoring marks are also the same.
[0051] The second critical dimension monitoring mark 20 extends from the first dense area A1 to the second dense area A2, and the CD of the second critical dimension monitoring mark 20 in the second dense area A2 shows a gradient increasing trend, that is, the CD of the second critical dimension monitoring mark 20 gradually increases, and the increased CD may be the same or different.
[0052] In the second dense area A2, the critical dimension monitoring mark structure further includes a fourth critical dimension monitoring mark 40, which is located between adjacent second critical dimension monitoring marks 20, and the fourth critical dimension monitoring mark 40 is close to the first critical dimension monitoring mark 10. Since the CD of the second critical dimension monitoring mark 20 increases gradually in the second dense area A2 from the first dense area A1 to the sparse area B, the fourth critical dimension monitoring mark 40 is located close to the first dense area A1.
[0053] The third critical dimension monitoring mark 30 extends from the first dense area A1 to the sparse area B. In the first dense area A1 and the second dense area A2, the CD of the third critical dimension monitoring mark 30 remains unchanged. In the sparse area B2, the CD of the third critical dimension monitoring mark 30 increases gradiently, that is, the CD of the third critical dimension monitoring mark 30 gradually increases, and the increased CD may be the same or different.
[0054] In this embodiment, the CD gradient of the second key dimension monitoring mark 20 in the second dense area A2 and the CD gradient of the third key dimension monitoring mark 30 in the sparse area B are designed to monitor the possible situation where the CD no longer changes with energy, and at the same time monitor whether the CD gradients have the same change law, so as to determine the optimal lithography conditions and achieve the purpose of effectively monitoring the actual changes of CD in the wafer surface.
[0055] In the first embodiment, the CD of the third critical dimension monitoring mark 30 in the sparse area B has a gradient change, and in the second embodiment, the CD of the second critical dimension monitoring mark 20 in the second dense area A2 has a gradient change. In the third embodiment, the CD of the third critical dimension monitoring mark 30 in the sparse area B has a gradient change, and the CD of the second critical dimension monitoring mark 20 in the second dense area A2 also has a gradient change. In other embodiments, the CD of the first critical dimension monitoring mark 10, the second critical dimension monitoring mark 20 or the third critical dimension monitoring mark 30 may also be set in the first dense area A1 to have a gradient change, or the CD gradient may also be set in both the first dense area A1 and the second dense area A2, and the present invention does not limit this.
[0056] The critical dimension monitoring mark structure described in the above embodiment may be a critical dimension monitoring mark structure formed by photoresist, or a pattern exposed in the photoresist may be a critical dimension monitoring mark structure.
[0057] In the above embodiments, the lengths of the dense area A and the sparse area B in the first direction X may be the same or different. Similarly, the lengths of the first dense area A1 and the second dense area A2 in the first direction X may be the same or different. The length of each area may be determined according to actual needs, and the present invention does not limit this.
[0058] In summary, the key dimension monitoring mark structure provided by the utility model includes a plurality of key dimension monitoring marks extending along a first direction and arranged along a second direction, and the key dimension monitoring mark structure includes a dense area and a sparse area in the first direction, and the CD of the key dimension monitoring mark in the dense area and / or the sparse area has a gradient change. The utility model designs a CD gradient to monitor the possible situation that the CD no longer changes with energy, and can simultaneously monitor whether the CD gradient has the same change law, so as to determine the optimal lithography conditions, and achieve the purpose of effectively monitoring the real change of CD in the wafer surface.
[0059] It should be noted that the embodiments in this specification are described in a progressive manner, and the structures described later focus on the differences from the methods described previously, and the similarities and similarities between the various parts can be referred to each other.
[0060] The above description is only a description of the preferred embodiment of the utility model, and is not any limitation on the scope of rights of the utility model. Any technical personnel in this field can make possible changes and modifications to the technical solution of the utility model by using the methods and technical contents disclosed above without departing from the spirit and scope of the utility model. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the utility model without departing from the content of the technical solution of the utility model are within the protection scope of the technical solution of the utility model.
Claims
1. A critical dimension monitoring mark structure, characterized in that: It comprises a plurality of key dimension monitoring marks extending along a first direction and arranged along a second direction. The key dimension monitoring mark structure comprises a dense area and a sparse area in the first direction. The CD of the key dimension monitoring marks in the dense area and / or the sparse area has a gradient change.
2. The critical dimension monitoring mark structure according to claim 1, characterized in that: In a direction from the dense area to the sparse area, the CD of the critical dimension monitoring mark increases gradually.
3. The critical dimension monitoring mark structure according to claim 1, characterized in that: The dense area includes a first dense area and a second dense area, the second dense area is located between the first dense area and the sparse area, and the density of the critical dimension monitoring mark in the first dense area is greater than the density of the critical dimension monitoring mark in the second dense area.
4. The critical dimension monitoring mark structure according to claim 3, characterized in that: The key dimension monitoring mark includes three lengths, the length of the first key dimension monitoring mark is smaller than the length of the second key dimension monitoring mark, and the length of the second key dimension monitoring mark is smaller than the length of the third key dimension monitoring mark; the first key dimension monitoring mark is located in the first dense area, the second key dimension monitoring mark is located in the first dense area and the second dense area, and the third key dimension monitoring mark is located in the first dense area, the second dense area and the sparse area.
5. The critical dimension monitoring mark structure according to claim 4, characterized in that: In the first dense area, CDs of the first critical dimension monitoring mark, the second critical dimension monitoring mark, and the third critical dimension monitoring mark are the same.
6. The critical dimension monitoring mark structure according to claim 4, characterized in that: The key dimension monitoring mark structure includes a third key dimension monitoring mark, and the third key dimension monitoring mark is located in the middle position of the first dense area and the second dense area, so that the first dense area and the second dense area both form a vertically symmetrical structure with the third key dimension monitoring mark as the symmetry axis.
7. The critical dimension monitoring mark structure according to claim 6, characterized in that: In the first dense area, the first critical dimension monitoring mark and the second critical dimension monitoring mark are alternately arranged in the second direction; and the CD of the third critical dimension monitoring mark in the sparse area has a gradient change.
8. The critical dimension monitoring mark structure according to claim 6, characterized in that: In the first dense area, two of the first critical dimension monitoring marks are arranged between adjacent second critical dimension monitoring marks, and one of the first critical dimension monitoring marks is arranged between the second critical dimension monitoring mark and the third critical dimension monitoring mark; the CD of the second critical dimension monitoring mark in the second dense area has a gradient change.
9. The critical dimension monitoring mark structure according to claim 8, characterized in that: In the second dense area, the CD monitoring mark structure further includes a fourth CD monitoring mark, wherein the fourth CD monitoring mark is located between adjacent second CD monitoring marks and is close to the first CD monitoring mark.
10. The critical dimension monitoring mark structure according to claim 6, characterized in that: The CD of the second CD monitor mark in the second dense area has a gradient change, and the CD of the third CD monitor mark in the sparse area has a gradient change.