Method for Correcting Patterns in Surface Plasmon Lithography

Abstract

The present invention discloses a method for correcting surface plasma lithography patterns, comprising: forming a plurality of test patterns on a test mask, each test pattern being characterized by at least a first test parameter and a second test parameter related to the first test parameter; exposing a photoresist layer using the test mask containing the test patterns to form a plurality of photoresist patterns, each photoresist pattern being characterized by at least a first exposure parameter and a second exposure parameter related to the first exposure parameter; establishing a first data table based on the correspondence between the first and second test parameters of the test patterns and the first and second exposure parameters of the photoresist patterns; processing the first data table according to the first exposure parameter to obtain a second data table; correcting the second test parameters of a plurality of design patterns based on the second data table to obtain corrected design patterns, and using the corrected design patterns to manufacture a mask for exposure.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor photolithography, and in particular to a method for correcting surface plasma photolithography patterns. Background Art

[0002] Photolithography, a key technology in integrated circuit manufacturing, determines the minimum size achievable throughout the entire IC manufacturing process. The primary purpose of the photolithography process is to transfer the design pattern from a mask onto a silicon wafer. In traditional photolithography, a light source illuminates a mask containing the design pattern to be transferred. A projection system then projects the design pattern onto a photoresist. After exposure, the photoresist undergoes a chemical reaction. After baking, development, and cleaning steps, a photoresist pattern corresponding to the design pattern on the mask is formed on the silicon wafer. However, due to the constraints of the optical diffraction limit, this photolithography technique typically only achieves a resolution of half a wavelength.

[0003] With the development of near-field optics, the manipulation and regulation of evanescent waves has become possible. Methods that break the diffraction limit, represented by surface plasmon-based lithography, have begun to be gradually applied to the manufacturing process of integrated circuits. Surface plasmon-based lithography uses a variety of film layer structures and does not require the use of complex lenses. Using surface plasmon-based lithography, it is possible to achieve lithographic images much smaller than the wavelength of the light source at a large wavelength. However, when using surface plasmon lithography for exposure, due to the complex principles of plasma lithography and the many factors that affect it, there is an error between the obtained photoresist pattern and the designed pattern on the mask. The existence of this problem has limited the promotion and application of surface plasmon lithography in related fields. Summary of the Invention

[0004] In view of the above problems, the present invention provides a method for correcting surface plasma lithography patterns to reduce the problem of large errors between the lithography pattern and the target pattern when using surface plasma lithography for exposure.

[0005] To achieve the above-mentioned object, the present invention provides a method for correcting surface plasma lithography patterns, comprising: forming a plurality of test patterns on a test mask, each test pattern being characterized by at least a first test parameter and a second test parameter related to the first test parameter; exposing a photoresist layer using the test mask containing the test patterns to form a plurality of photoresist patterns, each photoresist pattern being characterized by at least a first exposure parameter and a second exposure parameter related to the first exposure parameter; establishing a first data table based on a correspondence between the first test parameter and the second test parameter of the test pattern and the first exposure parameter and the second exposure parameter of the photoresist pattern; processing the first data table according to the first exposure parameter to obtain a second data table; and correcting the second test parameters of a plurality of design patterns based on the second data table to obtain corrected design patterns, and using the corrected design patterns to produce a mask for exposure.

[0006] According to an embodiment of the present invention, at least two test patterns in the plurality of test patterns have the same first test parameter.

[0007] According to an embodiment of the present invention, the first test parameter is the arrangement period of the lines of the test pattern, and the second test parameter is the line width of the lines of the test pattern or the spacing between two lines of the test pattern; the first exposure parameter is the arrangement period of the lines of the photoresist pattern, and the second exposure parameter is the line width of the lines of the photoresist pattern or the spacing between two lines of the photoresist pattern.

[0008] According to an embodiment of the present invention, the first exposure parameter of each photoresist pattern is the same as the first test parameter of the test pattern corresponding to the photoresist pattern.

[0009] According to an embodiment of the present invention, processing a first data table according to a first exposure parameter to obtain a second data table includes: selecting each test pattern as a target pattern in turn, searching the first data table for at least two first exposure parameters that are identical to the first test parameters of the target pattern; obtaining a second exposure parameter related to the at least two first exposure parameters; selecting, from all related second exposure parameters, a second exposure parameter that is closest to the second test parameter of the target pattern as a preferred second exposure parameter; searching the first data table for a preferred second test parameter that is identical to the first test parameter of the target pattern and corresponds to the preferred second exposure parameter; and establishing a second data table based on the first test parameters, second test parameters, and preferred second test parameters of all target patterns.

[0010] According to an embodiment of the present invention, the second test parameters of multiple design graphics are respectively corrected based on the second data table to obtain corrected design graphics, and the corrected design graphics are used to make a mask for exposure, including: correcting the second test parameters of each design graphic in the second data table to the preferred second test parameters to obtain the corrected design graphics, and using the corrected design graphics to make a mask for exposure.

[0011] According to an embodiment of the present invention, the plurality of test patterns are arranged into a one-dimensional periodic test pattern.

[0012] According to an embodiment of the present invention, the one-dimensional periodic test pattern includes a horizontal line periodic pattern or a vertical line periodic pattern.

[0013] According to an embodiment of the present invention, in the horizontal line periodic pattern or the vertical line periodic pattern, the arrangement period of the lines is equal to the sum of the line width and the spacing of the lines.

[0014] According to an embodiment of the present invention, a test mask containing a test pattern is used to expose a photoresist layer to form a plurality of photoresist patterns, each photoresist pattern is characterized by at least a first exposure parameter and a second exposure parameter related to the first exposure parameter, including: exposing the photoresist layer three times using a test mask containing a test pattern, each exposure forming a plurality of photoresist patterns, each test pattern in the plurality of photoresist patterns forming three photoresist patterns after three exposures; and taking the average value of the first exposure parameter and the average value of the second exposure parameter of the three photoresist patterns as the first exposure parameter and the second exposure parameter of the photoresist pattern corresponding to the test pattern.

[0015] According to the above-described embodiment of the present invention, a surface plasmon lithography pattern correction method provides a method for correcting surface plasmon lithography patterns. By using a table lookup approach, the method can be used to perform targeted corrections to the lithography pattern in a relatively short period of time, accurately reducing the error between the lithography pattern and the target pattern. The method is simple, time-saving, labor-saving, accurate, and efficient. The data in the data table are all experimentally obtained. Compared to experimental data obtained through fitting, the surface plasmon lithography pattern correction method provided by this application ensures the reliability of pattern correction, further contributing to the promotion and application of surface plasmon lithography in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a surface plasma lithography principle according to an embodiment of the present invention is shown schematically;

[0017] Figure 2 A flow chart of a method for correcting a surface plasma lithography pattern according to an embodiment of the present invention is schematically shown.

[0018]

Description of the accompanying drawings

[0019] 1 wafer;

[0020] 2 photoresist layer;

[0021] 3. Metallic silver film;

[0022] 4 polymer material layer;

[0023] 5. Mask;

[0024] 6. Light source. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0026] In traditional photolithography, a rule-based optical proximity effect is used to correct various design patterns. The corrected design patterns are then fabricated onto a mask, and after exposure, the error between the resulting photoresist pattern and the design pattern is reduced. However, because traditional photolithography can effectively expose a wide range of pattern sizes, the correction process requires designing a variety of patterns that cover all possible corrections. If a one-by-one enumeration approach is used, the amount of data is large and outside the acceptable range. Even if a table is created, using a lookup table will increase the time cost and be time-consuming and labor-intensive. For these reasons, traditional photolithography typically uses fitting to derive data for correcting design patterns, which also results in some corrections not being supported by actual exposure data.

[0027] Surface plasma lithography technology can be used to expose patterns with smaller periods (such as 1:1 lines with a 260nm period) using a light source with a larger wavelength (such as 365nm). The effective exposure size range is small. In theory, a design pattern is designed based on the desired target pattern, and the photoresist pattern obtained by exposing the photoresist using a mask with the design pattern should be consistent with the design pattern (the desired target pattern). However, due to the complex principles of plasma lithography and the many factors that affect it, there are errors between the obtained photoresist pattern and the design pattern on the mask, and the desired target pattern cannot be obtained. To this end, the design pattern needs to be corrected so that the photoresist pattern obtained based on the corrected design pattern is as consistent as possible with the desired target pattern. All patterns that can be corrected during the correction process are called test patterns.

[0028] According to embodiments of the present invention, based on the desired target pattern, all correctable design pattern data can be listed one by one at a data node using a specific step size, with acceptable data volume. Furthermore, during the correction process, the design pattern is corrected based on the actual post-exposure data, ensuring the reliability of the correction. Correcting the design pattern through a table lookup is simple and can accurately reduce the error between the photolithographic pattern and the desired target pattern.

[0029] Figure 1 The schematic diagram of the surface plasmon lithography principle according to an embodiment of the present invention is shown schematically.

[0030] like Figure 1 As shown, light from a light source 6 irradiates a test mask 5, which has multiple test patterns to be transferred. The test patterns are recorded on the photoresist layer 2 by a light wave diffraction system composed of a metallic silver film 3 and a polymer material layer 4. After development and other cleaning steps, a photoresist pattern identical to the test patterns is obtained on the wafer 1. The polymer material layer 4 can also be a film layer of other materials.

[0031] According to an overall inventive concept of the present invention, a method for correcting surface plasma lithography patterns is provided, comprising: forming a plurality of test patterns on a test mask, each test pattern being characterized by at least a first test parameter and a second test parameter related to the first test parameter; exposing a photoresist layer using the test mask containing the test patterns to form a plurality of photoresist patterns, each photoresist pattern being characterized by at least a first exposure parameter and a second exposure parameter related to the first exposure parameter; establishing a first data table based on a correspondence between the first test parameter and the second test parameter of the test pattern and the first exposure parameter and the second exposure parameter of the photoresist pattern; processing the first data table according to the first exposure parameter to obtain a second data table; and correcting the second test parameters of a plurality of design patterns based on the second data table to obtain corrected design patterns, and using the corrected design patterns to produce a mask for exposure.

[0032] Figure 2 A flow chart of a method for correcting a surface plasma lithography pattern according to an embodiment of the present invention is schematically shown.

[0033] like Figure 2 As shown, the method includes steps S201 to S205.

[0034] Step S201 : forming a plurality of test patterns on a test mask, wherein each test pattern is characterized by at least a first test parameter and a second test parameter related to the first test parameter.

[0035] According to an embodiment of the present invention, the test pattern may include a one-dimensional periodic test pattern, and the one-dimensional periodic test pattern may further include: a horizontal line periodic pattern and a vertical line periodic pattern, in which the period of the line arrangement is equal to the sum of the line width of the line and the spacing between the two lines.

[0036] According to an embodiment of the present invention, the test pattern includes various patterns with different periods designed based on line width nodes, with a minimum resolution as the step value. The minimum resolution step value can be 1 nm. During the design process, the first test parameter can be the period of the line arrangement designed based on the minimum step value; the second test parameter can be the line width or the spacing between two lines. The relationship between the first and second test parameters is that the period of the line arrangement is equal to the sum of the line width and the spacing between two lines.

[0037] According to an embodiment of the present invention, each test pattern is characterized by at least a first test parameter and a second test parameter. During the design process, at least two test patterns should have the same first test parameter, so that the preferred solution can be determined based on the same first test parameter during comparison. In this invention, a case where the first test parameter is 51-53 nm and the second test parameter is 24-26 nm is used as an example, where every three test patterns have the same first test parameter. The specific test pattern parameters are shown in Table 1.

[0038] Table 1 Test graphics parameters

[0039]

[0040] In step S202, the photoresist layer is exposed using a test mask containing a test pattern to form a plurality of photoresist patterns, each of which is characterized by at least a first exposure parameter and a second exposure parameter related to the first exposure parameter.

[0041] According to an embodiment of the present invention, multiple test patterns are fabricated onto a reticle by electron beam direct writing to obtain a test mask containing multiple test patterns. A photoresist layer is exposed three times using the test mask containing the multiple test patterns, with each exposure forming multiple photoresist patterns. Each of the multiple test patterns forms three photoresist patterns after the three exposures.

[0042] According to an embodiment of the present invention, the average value of the period of the three photoresist patterns in each test pattern is used as the first exposure parameter corresponding to the first test parameter, and the average value of the line width or the average value of the spacing between the lines in the three photoresist patterns in each test pattern is used as the second exposure parameter corresponding to the second test parameter. The relationship between the first exposure parameter and the second exposure parameter is that the period of the line arrangement is equal to the sum of the line width and the spacing between the two lines.

[0043] According to an embodiment of the present invention, the first exposure parameter of each photoresist pattern is the same as the first test parameter of the test pattern corresponding to the photoresist pattern. That is, the period value of the same test pattern and the photoresist pattern is the same. The parameters of the photoresist pattern obtained by exposing the photoresist layer using a mask made using the test pattern parameters in Table 1 are shown in Table 2.

[0044] Table 2 Photoresist pattern parameters

[0045]

[0046] In step S203, a first data table is established based on the correspondence between the first test parameter and the second test parameter of the test pattern and the first exposure parameter and the second exposure parameter of the photoresist pattern.

[0047] Table 3: First data table established based on test pattern parameters and photoresist pattern parameters

[0048]

[0049] According to an embodiment of the present invention, a first data table is established by mapping the first test parameters and the second test parameters of the test pattern to the first exposure parameters and the second exposure parameters of the photoresist pattern according to a one-to-one correspondence. The first data table established based on the test pattern parameters in Table 1 and the photoresist pattern parameters in Table 2 is shown in Table 3.

[0050] According to the embodiment of the present invention, the establishment of the first data table facilitates the calculation of the correction amount for the second test parameter in a simple, rapid and targeted manner, and the establishment of the second data table based on the calculated correction amount.

[0051] In S204 , the first data table is processed according to the first exposure parameter to obtain a second data table.

[0052] According to an embodiment of the present invention, each test pattern is sequentially selected as a target pattern, and at least two first exposure parameters identical to the first test parameters of the target pattern are searched in a first data table; second exposure parameters associated with the at least two first exposure parameters are obtained. For example, using the test pattern in Table 3, where the first test parameter is 52nm and the second test parameter is 25nm, as the target pattern, three first exposure parameters identical to the first test parameter of 52nm are found in the first data table. The second exposure parameters associated with these three first exposure parameters are 19.1nm, 20.6nm, and 26nm, respectively.

[0053] According to an embodiment of the present invention, a second exposure parameter that is closest to the second test parameter of the target pattern is selected from all relevant second exposure parameters as the preferred second exposure parameter. The second test parameter of the target pattern is 25nm. Among the three second exposure parameters found, 26nm is closest to 25nm, and 26nm is selected as the preferred second exposure parameter.

[0054] According to an embodiment of the present invention, a preferred second test parameter that is identical to the first test parameter of the target pattern and corresponds to the preferred second exposure parameter is searched in a first data table; a second data table is established based on the first test parameters, second test parameters, and preferred second test parameters of all target patterns. In the first data table, a second test parameter of 26nm is found that corresponds to a first test parameter of 52nm and a preferred second exposure parameter of 26nm. 26nm is the preferred second test parameter, indicating that the second test parameter of 25nm of the design pattern corresponding to the desired target pattern needs to be corrected to the preferred second test parameter of 26nm. Only then can the corrected design pattern be used to produce a mask for final exposure and obtain a photoresist pattern. The first data table is processed according to the first exposure parameters to obtain a second data table, as shown in Table 4.

[0055] Table 4: The first data table is processed according to the first exposure parameter to obtain the second data table

[0056]

[0057] According to an embodiment of the present invention, the second data table can quickly and efficiently find the preferred second test parameters, effectively correct the design graphics corresponding to the desired target graphics, and the data are all obtained from experiments, ensuring the accuracy and reliability of the data during the correction process.

[0058] In step S205 , the second test parameters of the plurality of design patterns are respectively corrected based on the second data table to obtain corrected design patterns, and masks for exposure are manufactured using the corrected design patterns.

[0059] According to an embodiment of the present invention, the second test parameters of each design pattern in the second data table are corrected to the preferred second test parameters to obtain a corrected design pattern, and a mask for exposure is manufactured using the corrected design pattern.

[0060] According to an embodiment of the present invention, taking a desired target pattern as an example with a first test parameter of 53nm and a second test parameter of 25nm, theoretically, the design pattern corresponding to the desired target pattern has a first test parameter of 53nm and a second test parameter of 25nm. According to the second data table, the corresponding preferred second test parameter is found to be 24nm. That is, the dimensions of the design pattern are corrected to a first test parameter of 53nm and a second test parameter of 24nm, resulting in a corrected design pattern. The corrected design pattern is then used to produce a final mask for exposure. According to the first data table, when the first test parameter is 53nm and the second test parameter is 24nm, the corresponding photoresist pattern parameters have a first exposure parameter of 53nm and a second exposure parameter of 22.5nm, resulting in a 2.5nm error from the second test parameter of 25nm for the desired target pattern.

[0061] According to an embodiment of the present invention, if the design pattern is not corrected, according to the first data table, when the first test parameter of the uncorrected design pattern is found to be 53nm and the second test parameter is 25nm, the corresponding first exposure parameter in the photoresist pattern parameters is 53nm and the second exposure parameter is 29.3nm. The error with the second test parameter of 25nm of the desired target pattern is 4.3nm, which is significantly greater than the above-mentioned error of 2.5nm after correction.

[0062] It can be understood that in the above description, a test mask containing a test pattern is used to expose the photoresist layer to obtain multiple photoresist patterns corresponding to the test pattern, and a mask containing a corrected design pattern is used to expose the photoresist layer to obtain multiple photoresist patterns corresponding to the design pattern. The multiple photoresist patterns corresponding to the design pattern are as consistent as possible with the target pattern to be obtained.

[0063] According to an embodiment of the present invention, a test pattern, a plurality of photoresist patterns corresponding to the test pattern, a design pattern, a corrected design pattern, a plurality of photoresist patterns corresponding to the design pattern, and a desired target pattern can all be characterized by the period of line arrangement, the line width of the line, and the spacing between two lines.

[0064] According to an embodiment of the present invention, the second test parameters of the design pattern are corrected based on the second data table to obtain a corrected design pattern. The corrected design pattern is used to make a mask for exposure, which can accurately and effectively reduce the error between the photoresist pattern and the desired target pattern, and subsequent procedures such as exposure can be performed under the same exposure conditions.

[0065] The parameters in the above table and the parameters in the examples are only an embodiment of the present application. They are listed for ease of understanding and do not mean that the present application is only applicable to the above parameters. In actual working processes, different parameters can be produced according to different structures and materials in the plasma lithography process, and the corresponding parameter ranges are also different.

[0066] It should also be noted that directional terms such as "upper," "lower," "front," "back," "left," and "right" mentioned in the embodiments are merely references to the directions in the accompanying drawings and are not intended to limit the scope of protection of the present invention. Throughout the drawings, identical elements are represented by identical or similar reference numerals. Conventional structures or configurations will be omitted where they may cause confusion in understanding the present invention.

[0067] Furthermore, the shapes and sizes of the components in the figures do not reflect actual size or proportion, but are merely illustrative of the contents of the embodiments of the present invention. Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0068] Similarly, it should be understood that in order to streamline the present invention and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this method of invention should not be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments of the preceding invention. Accordingly, the claims that follow the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the present invention.

[0069] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for correcting a surface plasma lithography pattern, comprising: forming a plurality of test patterns on a test mask, each of the test patterns being characterized by at least a first test parameter and a second test parameter related to the first test parameter; exposing the photoresist layer using a test mask containing the test pattern to form a plurality of photoresist patterns, each of the photoresist patterns being characterized by at least a first exposure parameter and a second exposure parameter related to the first exposure parameter; Establishing a first data table based on a correspondence between the first test parameter and the second test parameter of the test pattern and the first exposure parameter and the second exposure parameter of the photoresist pattern; Processing the first data table according to the first exposure parameter to obtain a second data table; as well as Correcting the second test parameters of the plurality of design patterns based on the second data table to obtain corrected design patterns, and using the corrected design patterns to produce a mask for exposure; The method of processing the first data table according to the first exposure parameter to obtain the second data table includes: selecting each test pattern as a target pattern in turn, searching the first data table for at least two first exposure parameters that are identical to the first test parameters of the target pattern; obtaining second exposure parameters related to the at least two first exposure parameters; selecting, from all related second exposure parameters, a second exposure parameter that is closest to the second test parameter of the target pattern as a preferred second exposure parameter; searching the first data table for a preferred second test parameter that is identical to the first test parameter of the target pattern and corresponds to the preferred second exposure parameter; and establishing the second data table based on the first test parameters, second test parameters, and preferred second test parameters of all target patterns.

2. The correction method according to claim 1, wherein: At least two test patterns among the plurality of test patterns have the same first test parameter.

3. The correction method according to claim 1, wherein: The first test parameter is the arrangement period of the lines of the test pattern, and the second test parameter is the line width of the lines of the test pattern or the distance between two lines of the test pattern; The first exposure parameter is the arrangement period of the lines of the photoresist pattern, and the second exposure parameter is the line width of the lines of the photoresist pattern or the distance between two lines of the photoresist pattern.

4. The correction method according to any one of claims 1 to 3, wherein: The first exposure parameter of each photoresist pattern is the same as the first test parameter of the test pattern corresponding to the photoresist pattern.

5. The correction method according to claim 1, wherein: The method further comprises: modifying second test parameters of a plurality of design patterns based on the second data table to obtain modified design patterns, and using the modified design patterns to produce a mask for exposure, comprising: The second test parameters of each design pattern in the second data table are corrected to the preferred second test parameters to obtain a corrected design pattern, and a mask for exposure is manufactured using the corrected design pattern.

6. The correction method according to claim 3, wherein: A plurality of the test patterns are arranged into a one-dimensional periodic test pattern.

7. The correction method according to claim 6, wherein: The one-dimensional periodic test pattern includes: a horizontal line periodic pattern or a vertical line periodic pattern.

8. The correction method according to claim 7, wherein: In a horizontal line periodic pattern or a vertical line periodic pattern, the arrangement period of the lines is equal to the sum of the line width and the spacing between the lines.

9. The correction method according to claim 1, wherein: Exposing the photoresist layer using a test mask containing the test pattern to form a plurality of photoresist patterns, each of the photoresist patterns being characterized by at least a first exposure parameter and a second exposure parameter related to the first exposure parameter, including: Expose the photoresist layer three times using a test mask containing the test pattern, each exposure forming a plurality of photoresist patterns, and each of the plurality of test patterns forms three photoresist patterns after the three exposures; and An average value of the first exposure parameters and an average value of the second exposure parameters of the three photoresist patterns are taken as the first exposure parameter and the second exposure parameter of the photoresist pattern corresponding to the test pattern.

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