Method for monitoring and scanning continuous depth-of-field extension program of photoetching machine
By introducing sub-resolution assisted graphics into the mask plate, and using the continuous depth of field extension program of the scanning lithography machine to transfer the graphics to the photoresist layer, obtaining the developed morphology to monitor the continuous depth of field extension program, the problem of lack of monitoring methods in the prior art is solved, and effective monitoring and control of fluctuations of this function is achieved.
Patent Information
- Application Number
- CN202510105518.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2025-03-25
AI Technical Summary
The prior art lacks a method for monitoring the continuous depth of field expansion program of scanning lithography machines, resulting in the inability to effectively monitor and control the fluctuations of this function.
By providing a mask plate, including line graphics and subresolution assisted graphics with periodic structures, the continuous depth of field expansion program of the scanning lithography machine is used to transfer the graphics to the photoresist layer on the wafer to obtain the developed morphology of the subresolution assisted graphics to determine whether there are fluctuations in the continuous depth of field expansion program.
The continuous depth of field expansion program of the scanning lithography machine after development morphology monitoring through sub-resolution assisted graphics is realized, which can effectively determine whether the process window of the design structure is affected and ensure that the function operates within a reasonable range.
Smart Images
Figure CN119689797A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for monitoring a continuous depth of field extension program of a scanning lithography machine. Background Art
[0002] The scanning lithography machine (scanner) adopts the step-and-scan exposure method. The light source does not project the entire pattern on the mask onto the wafer at one time. The exposure system irradiates the mask through a slit exposure belt. The mask stage moves in one direction under the slit, which is equivalent to the exposure system scanning the mask. Synchronously with the scanning of the mask, the wafer moves in the opposite direction at 1 / 4 of the speed.
[0003] CDP: (Continuous DOF Expansion Procedure) is an optional function of the scanning lithography machine. Its application can effectively increase the process window of ISO (isolation) structure without affecting the production volume. Figure 1 As shown, during exposure, the wafer is tilted at a certain angle along the scanning direction of the scanning lithography machine, and the wafer moves up and down at the same time.
[0004] However, whether for lithography machine manufacturers or semiconductor wafer manufacturers, there is little research on the continuous depth of field extension program function, and there is a lack of monitoring methods for the continuous depth of field extension program function.
[0005] In order to solve the above problems, it is necessary to propose a new method for monitoring the continuous depth of field extension program of a scanning lithography machine. Summary of the invention
[0006] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a method for monitoring a continuous depth of field extension program of a scanning lithography machine, so as to solve the problem of the lack of a continuous depth of field extension program function in the prior art monitoring method.
[0007] To achieve the above-mentioned object and other related objects, the present invention provides a method for monitoring a continuous depth of field extension procedure of a scanning lithography machine, comprising:
[0008] Step 1, providing a mask, wherein the mask includes line patterns of a periodic structure, and sub-resolution auxiliary patterns are inserted between the line patterns;
[0009] Step 2: using the continuous depth of field extension program of the scanning lithography machine, the pattern of the mask is transferred to the photoresist layer on the wafer. During exposure, the wafer is tilted at a certain angle along the scanning direction of the scanning lithography machine, and the wafer moves up and down at the same time;
[0010] Step three: obtaining the post-development morphology of the sub-resolution auxiliary pattern on the photoresist layer, and judging whether the continuous depth of field extension program has fluctuations according to the post-development morphology.
[0011] Preferably, the line width of the line pattern in step 1 is 80 nm, and the distance between two adjacent line patterns is 300 to 500 nm.
[0012] Preferably, the line width of the sub-resolution auxiliary pattern in step 1 is 20 to 35 nm.
[0013] Preferably, in step 1, the sub-resolution auxiliary patterns are inserted between the line patterns in an equidistant insertion manner.
[0014] Preferably, in step three, under the condition of the same line pattern spacing and the sub-resolution pattern, as the amplitude of the continuous depth of field extension program of the scanning lithography machine increases from a first set value to a second set value, the post-development morphology of the sub-resolution auxiliary pattern on the photoresist layer shows a process from nothing to something and then gradually widening.
[0015] Preferably, the amplitude of the continuous depth of field extension program of the scanning lithography machine in step three is increased from 0.04um to 0.12um.
[0016] Preferably, in step three, under the condition of the continuous depth of field extension program of the same scanning lithography machine, when the spacing of the line pattern increases from the third set value to the fourth set value, the post-development morphology of the sub-resolution auxiliary pattern on the photoresist layer shows a process from presence to absence.
[0017] Preferably, the spacing of the line patterns in step three gradually changes from 380 nm to 400 nm.
[0018] Preferably, in step three, under the condition of the continuous depth of field extension procedure of the same scanning lithography machine, when the line width of the sub-resolution auxiliary graphic is reduced from the fifth set value to the sixth set value, the post-development morphology of the sub-resolution auxiliary graphic on the photoresist layer shows a process from presence to absence.
[0019] Preferably, the line width of the sub-resolution auxiliary pattern in step three gradually changes from 22 nm to 20 nm.
[0020] As described above, the method for monitoring the continuous depth of field extension program of a scanning lithography machine of the present invention has the following beneficial effects:
[0021] The present invention can monitor the continuous depth of field extension program of a scanning photolithography machine through the post-development morphology of sub-resolution auxiliary patterns on a photoresist layer. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 Shown is a schematic diagram of the operation of a continuous depth of field extension program of the prior art;
[0023] Figure 2 Shown is a schematic diagram of a method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to the present invention;
[0024] Figure 3 Shown is a schematic diagram of a mask of the present invention;
[0025] Figure 4 It is a schematic diagram showing the change of amplitude and SRAF morphology of the continuous depth of field extension program of the present invention;
[0026] Figure 5 Shown is a schematic diagram of the change in the spacing of the line pattern and the SRAF morphology of the present invention;
[0027] Figure 6 It is a schematic diagram showing the changes in line width and SRAF morphology of the sub-resolution auxiliary pattern of the present invention. DETAILED DESCRIPTION
[0028] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.
[0029] See also Figure 2 The present invention provides a method for monitoring a continuous depth of field extension program of a scanning lithography machine, comprising:
[0030] Step 1, providing a mask, the mask including line patterns of a periodic structure, and sub-resolution auxiliary patterns (SRAF) inserted between the line patterns;
[0031] In the embodiment of the present invention, the continuous depth of field extension program CDP can effectively enhance the process window of the design structure within a certain range. Figure 3 , the following mask is designed, the line width of the line pattern in step one is 80nm, the pitch between two adjacent line patterns is 300 to 500nm, and the line width of the sub-resolution auxiliary pattern in step one is 20 to 35nm.
[0032] In an embodiment of the present invention, in step 1, sub-resolution auxiliary graphics are inserted between line graphics in an equidistant insertion manner.
[0033] Step 2: Using the continuous depth of field extension program of the scanning lithography machine, the pattern of the mask is transferred to the photoresist layer on the wafer. During exposure, the wafer is tilted at a certain angle along the scanning direction of the scanning lithography machine, and the wafer moves up and down at the same time;
[0034] Step 3: Obtain the post-development morphology of the sub-resolution auxiliary pattern on the photoresist layer, and determine whether there is fluctuation in the continuous depth of field extension program based on the post-development morphology, and then determine whether the process window of the design structure is affected by it.
[0035] In the embodiments of the present invention, please refer to Figure 4 In step 3, under the same line pattern spacing and sub-resolution pattern, as the amplitude of the continuous depth of field extension program of the scanning lithography machine increases from the first set value to the second set value, the morphology of the sub-resolution auxiliary pattern after development on the photoresist layer is shown as from nothing to something ( Figure 4 e to d), and then gradually widens ( Figure 4 d to a). That is, the SRAF morphology change shows the enhancement of the SRAF process window, and the CDP is monitored in the reverse direction to see if it is within a reasonable range. The change of CDP directly affects the change of SRAF morphology, and also indirectly affects the process window of the designed structure.
[0036] In an embodiment of the present invention, the amplitude of the continuous depth of field extension program of the scanning lithography machine in step three is increased from 0.04um to 0.12um.
[0037] In the embodiments of the present invention, please refer to Figure 5 In step three, under the condition of continuous depth of field extension procedure of the same scanning lithography machine, when the spacing of the line pattern increases from the third set value to the fourth set value, the morphology of the sub-resolution auxiliary pattern after development on the photoresist layer shows a process from presence to absence.
[0038] In an embodiment of the present invention, the pitch of the line pattern in step three gradually changes from 380 nm to 400 nm.
[0039] In the embodiments of the present invention, please refer to Figure 6 In step three, under the condition of continuous depth of field extension procedure of the same scanning lithography machine, when the line width of the sub-resolution auxiliary pattern is reduced from the fifth set value to the sixth set value, the morphology of the sub-resolution auxiliary pattern after development on the photoresist layer shows a process from presence to absence.
[0040] In an embodiment of the present invention, the line width of the sub-resolution auxiliary pattern in step three gradually changes from 22 nm to 20 nm.
[0041] That is, under the same CDP setting, the changes in Pitch and SRAF size directly affect the morphology of SRAF. Pitch and SRAF size can vary within a certain range. Within the range of variation, the structure that meets the requirements can be determined as the main monitoring structure, thereby designing a simple mask to meet more structural requirements.
[0042] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.
[0043] In summary, the present invention can monitor the continuous depth of field extension process of the scanning photolithography machine through the post-development morphology of the sub-resolution auxiliary pattern on the photoresist layer. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.
[0044] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.
Claims
1. A method for monitoring a continuous depth of field extension procedure of a scanning lithography machine, characterized in that: At least: Step 1, providing a mask, wherein the mask includes line patterns of a periodic structure, and sub-resolution auxiliary patterns are inserted between the line patterns; Step 2: using the continuous depth of field extension program of the scanning lithography machine, the pattern of the mask is transferred to the photoresist layer on the wafer. During exposure, the wafer is tilted at a certain angle along the scanning direction of the scanning lithography machine, and the wafer moves up and down at the same time; Step three: obtaining the post-development morphology of the sub-resolution auxiliary pattern on the photoresist layer, and judging whether the continuous depth of field extension program has fluctuations according to the post-development morphology.
2. The method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to claim 1, characterized in that: The line width of the line pattern in step 1 is 80 nm, and the distance between two adjacent line patterns is 300 to 500 nm.
3. The method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to claim 1 or 2, characterized in that: The line width of the sub-resolution auxiliary pattern in step 1 is 20 to 35 nm.
4. The method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to claim 1, characterized in that: In step 1, the sub-resolution auxiliary graphics are inserted between the line graphics in an equidistant insertion manner.
5. The method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to claim 1, characterized in that: In step three, under the condition of the same line pattern spacing and the sub-resolution pattern, as the amplitude of the continuous depth of field extension program of the scanning lithography machine increases from a first set value to a second set value, the post-development morphology of the sub-resolution auxiliary pattern on the photoresist layer shows a process from nothing to something and then gradually widening.
6. The method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to claim 5, characterized in that: The amplitude of the continuous depth of field extension program of the scanning lithography machine in step three is increased from 0.04um to 0.12um.
7. The method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to claim 1, characterized in that: In step three, under the condition of the continuous depth of field extension procedure of the same scanning lithography machine, when the spacing of the line pattern increases from the third set value to the fourth set value, the post-development morphology of the sub-resolution auxiliary pattern on the photoresist layer shows a process from presence to absence.
8. The method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to claim 7, characterized in that: The spacing of the line pattern in step three gradually changes from 380 nm to 400 nm.
9. The method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to claim 1, characterized in that: In step three, under the condition of the continuous depth of field extension procedure of the same scanning lithography machine, when the line width of the sub-resolution auxiliary pattern is reduced from the fifth set value to the sixth set value, the post-development morphology of the sub-resolution auxiliary pattern on the photoresist layer shows a process from presence to absence.
10. The method for monitoring a continuous depth of field extension procedure of a scanning lithography machine according to claim 9, characterized in that: The line width of the sub-resolution auxiliary pattern in step three gradually changes from 22 nm to 20 nm.