Bifunctional molecular group structure for photoresist as well as synthesis method and use method of bifunctional molecular group structure
By synthesizing linkers containing carbon-oxygen or carbon-nitrogen chemical bonds in the photoresist, a bifunctional molecular cluster structure of PAG and PDQ molecules is formed, solving the problem of non-uniform mixing in the photoresist. This achieves uniformity of PAG and PDQ, as well as improved linewidth uniformity and roughness of the photoresist, meeting the diverse needs of users for chemical amplification photoresists.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2026-03-27
AI Technical Summary
The non-uniform mixing of PAG and PDQ molecules in existing photoresists leads to non-uniformity in photoresist linewidth and roughness, making it difficult to meet users' different needs for contrast and photosensitivity of chemically amplified photoresists.
PAG and PDQ molecules are synthesized using linkers containing carbon-oxygen or carbon-nitrogen chemical bonds. Through substitution reactions, bifunctional molecular clusters are formed, allowing the ratio of PAG and PDQ molecules to be adjustable, thus ensuring uniformity and the linewidth uniformity and roughness of the photoresist.
This method achieves uniform distribution of PAG and PDQ molecules in the photoresist, improves the linewidth uniformity and roughness of the photoresist, and meets the contrast and photosensitivity requirements of different users.
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Figure CN121735954A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of semiconductor integrated circuit manufacturing, and in particular to a bifunctional molecular group structure for photoresist. The present application also relates to a synthesis method of the bifunctional molecular group structure for photoresist. The present application also relates to a use method of photoresist using the bifunctional molecular group structure. BACKGROUND
[0002] Chemical amplification resist composition contains polymer resin, photo acid generator (PAG), additives and solvent. Conventional chemical amplification resist contains alkaline neutralizer, and photodecomposable quencher (PDQ) is an alkaline organic molecule which will decompose and lose alkalinity after light exposure.
[0003] PAG will decompose and generate acid ion H+ under light exposure; H+ will act as catalyst to make acid labile bond break during post exposure bake (PEB), thus changing the polarity of polymer and making it soluble in developer; the generated acid will further act on the deprotection reaction of polymer. PAG greatly increases the photosensitivity of chemical amplification resist and reduces the exposure energy.
[0004] As shown in FIG. 1, it is a schematic diagram of the action mechanism of PAG in photoresist in each step of the existing photoetch process; the steps of the existing photoetch process include: Figures 1A-1D As shown in FIG. 2, photoresist 102 is coated on wafer 101, and PAG molecules 103 are contained in photoresist 102.
[0005] Figure 1A As shown in FIG. 3, exposure is performed to transfer the pattern on mask plate 104 to photoresist 102, wherein light 105 will pass through the window area of mask plate 104 to irradiate the bottom photoresist 102 and thus achieve pattern transfer,
[0006] As shown in FIG. 4, post exposure bake is performed, and during post exposure bake, H+ will act as catalyst to make acid labile bond break, thus changing the polarity of polymer and making it soluble in developer. Figure 1B Figure 1B As shown in FIG. 5, post exposure bake is performed, and during post exposure bake, H+ will act as catalyst to make acid labile bond break, thus changing the polarity of polymer and making it soluble in developer.
[0007] As shown in FIG. 6, post exposure bake is performed, and during post exposure bake, H+ will act as catalyst to make acid labile bond break, thus changing the polarity of polymer and making it soluble in developer. Figure 1C As shown in FIG. 7, post exposure bake is performed, and during post exposure bake, H+ will act as catalyst to make acid labile bond break, thus changing the polarity of polymer and making it soluble in developer.
[0008] Figure 1D As shown, the photoresist 102 is developed by spraying organic developing solution, so that the exposed area of the photoresist 102 is removed to form the space pattern 102b, and the remaining photoresist 102 forms the strip 102a.
[0009] For PDQ, the PDQ in the exposed area loses alkalinity due to light, and cannot neutralize the acid decomposed by the photoacid generator, so the acid concentration in the photoresist remains at a high level; the PDQ in the unexposed area is not decomposed, and the alkalinity in the photoresist remains at a high level; the result is that the acid concentration difference between the exposed and unexposed areas is further enlarged, thereby improving the contrast of the photoresist.
[0010] As shown, the PDQ mechanism in the photoresist in each step of the existing photolithography process is shown in the schematic diagram. Figures 2A-2C
[0011] As shown, the photoresist 202 is coated on the wafer 201, and the photoresist 202 contains PDQ molecules 203. Figure 2A
[0012] As shown, the pattern on the mask plate is transferred to the photoresist 202 by exposure, Figure 2B In the process, the PDQ molecules 203 in the area of the photoresist 202 that is irradiated by light will decompose to form the structure shown by the mark 203a, which loses alkalinity. Figure 2B
[0013] As shown, the pattern structure of the photoresist 202 is formed by post-baking and developing with organic developing solution, including the space pattern 202b and the strip 202a. Figure 2C
[0014] Therefore, after adding PDQ to the photoresist, due to the characteristics of PDQ losing alkalinity after exposure and having alkalinity when not exposed, combined with the characteristics of PAG molecules generating acid after exposure, the acid concentration difference between the exposed and unexposed areas is further enlarged, thereby improving the contrast of the photoresist.
[0015] As shown, the distribution curves of the acid concentration and the base concentration in the exposed area and the unexposed area after mixing PDQ in the existing photolithography process are shown; the curve 301 is the acid concentration curve, and the curve 302 is the base concentration curve. As can be seen, the acid concentration in the exposed area is much higher than that in the unexposed area, and the base concentration in the exposed area is much lower than that in the unexposed area. Thus, the acid concentration and the base concentration shown by the arrow line 304 in the exposed area have a large difference and remain as acid, and the base concentration and the acid concentration shown by the arrow line 305 in the unexposed area also have a large difference and remain as base. At the boundary between the exposed area and the unexposed area, even if part of the acid diffuses into the unexposed area, it will be neutralized by the base in the unexposed area. Therefore, by adding PDQ to the photoresist, the contrast of the photoresist can be improved. Figure 3 As can be seen, the acid concentration in the exposed area is much higher than that in the unexposed area, and the base concentration in the exposed area is much lower than that in the unexposed area. Thus, the acid concentration and the base concentration shown by the arrow line 304 in the exposed area have a large difference and remain as acid, and the base concentration and the acid concentration shown by the arrow line 305 in the unexposed area also have a large difference and remain as base. At the boundary between the exposed area and the unexposed area, even if part of the acid diffuses into the unexposed area, it will be neutralized by the base in the unexposed area. Therefore, by adding PDQ to the photoresist, the contrast of the photoresist can be improved.
[0016] As shown in Figure 4 is a schematic diagram of the mixing of PAG and PDQ molecules in a photoresist that uses a mixture of PAG and PDQ; PAG molecules 402 and PDQ molecules 403 are mixed in photoresist 401, but direct mixing of PAG molecules 402 and PDQ molecules 403 can result in uneven mixing. Base excess can occur in region 404 and acid excess can occur in region 405.
[0017] To improve the uniformity of PAG and PDQ distribution in photoresist, there is a molecular structure in the prior art that synthesizes PAG and PDQ together to form a bifunctional group. This structure can ensure the uniformity of PAG molecules and PDQ molecules in photoresist, and ensure the uniformity and roughness of photoresist line width. However, the bifunctional molecule now exists by mixing PAG molecules and PDQ molecules in a 1:1 ratio through a linker.
[0018] As shown in Figure 5 is a schematic diagram of the mixing of PAG and PDQ molecules in a photoresist that uses a bifunctional molecule group synthesized from PAG and PDQ; photoresist 501 uses bifunctional molecule group 504 synthesized from PAG molecules 503 and PDQ molecules 502 through a linker, which can achieve uniform mixing of PAG molecules 503 and PDQ molecules 502. However, the prior art cannot achieve other PAG to PDQ ratios. SUMMARY
[0019] The technical problem to be solved by the present application is to provide a bifunctional molecule group structure for photoresist, which can set the ratio of PAG molecules and PDQ molecules, thereby ensuring the uniformity of PAG and PDQ in photoresist, ensuring the uniformity and roughness of photoresist line width, and meeting different user requirements for chemical amplification resist contrast and photosensitivity. To this end, the present application also provides a synthesis method for a bifunctional molecule group structure for photoresist. The present application also provides a use method of a photoresist using a bifunctional molecule group structure.
[0020] To solve the above technical problems, the bifunctional molecule group structure for photoresist provided by the present application comprises: a linker, PAG molecules and PDQ molecules.
[0021] The linker contains a carbon-oxygen chemical bond or a carbon-nitrogen chemical bond.
[0022] Each of the linkers has a number of PAG molecules and PDQ molecules synthesized in proportion, and the total number of the PAG molecules and the PDQ molecules is more than 3.
[0023] The PAG molecules are synthesized on the linker through the carbon-oxygen chemical bond.
[0024] The PDQ molecules are synthesized on the linker through the carbon-nitrogen chemical bond.
[0025] A further improvement is that the linker comprises a polyol ether.
[0026] A further improvement is that the polyol ether comprises a glycerol ether or a butanetetrol ether.
[0027] A further improvement is that the glycerol ether has a molecular structure of:
[0028]
[0029] R1, R2, and R3 in the molecular formula (1) represent three groups of the glycerol ether.
[0030] In the bifunctional molecular group structure, the PAG molecules are synthesized at one or two of R1, R2, and R3, and the types of the PAG molecules at different positions are the same or different.
[0031] The PDQ molecules are synthesized at the positions of R1, R2, and R3 that are not synthesized with the PAG molecules, and the types of the PDQ molecules at different positions are the same or different.
[0032] The ratio of the PAG molecules to the PDQ molecules is 1:2 or 2:1.
[0033] A further improvement is that the butanetetrol ether has a molecular structure of:
[0034]
[0035] R1, R2, R3, and R4 in the molecular formula (2) represent four groups of the butanetetrol ether.
[0036] In the bifunctional molecular group structure, the PAG molecules are synthesized at one or two or three of R1, R2, R3, and R4, and the types of the PAG molecules at different positions are the same or different.
[0037] The PDQ molecules are synthesized at the positions of R1, R2, R3, and R4 that are not synthesized with the PAG molecules, and the types of the PDQ molecules at different positions are the same or different.
[0038] The ratio of the PAG molecules to the PDQ molecules is 1:3 or 3:1.
[0039] A further improvement is that the PAG molecules comprise bis(cyclohexylsulfonyl)diazomethane or 3-hydroxy-2,5-dioxopyrrol-1-trifluoromethylsulfonate.
[0040] The molecular structure of the bis(cyclohexylsulfonyl)diazomethane is as follows:
[0041]
[0042] A further improvement is that the PDQ molecule adopts 1,3-dioxopyrrolo 3,4-tetrahydropyrrole-1-trifluoromethyl sulfonate, and the molecular structure is as follows:
[0043]
[0044] A further improvement is that the photoresist includes a bifunctional molecular structure, a polymer resin, an additive, and a solvent.
[0045] To solve the above technical problems, the synthesis method of the bifunctional molecular structure for the photoresist provided by the present application includes the following steps:
[0046] To solve the above technical problems, the use method of the photoresist adopting the bifunctional molecular structure provided by the present application includes the following steps:
[0047] The photoresist is coated on the wafer surface.
[0048] Pre-baking is performed.
[0049] Exposure and development are performed to form a photoresist pattern.
[0050] Post-baking is performed.
[0051] A further improvement is that, in the exposure, the PAG molecules in the exposed area release H+ and form an acid, and the PDQ molecules lose alkalinity.
[0052] A further improvement is that, in the post-baking, the photoresist in the exposed area is decomposed under the catalysis of the acid and generates a new acid; the PDQ molecules in the unexposed area neutralize the acid diffused into the unexposed area.
[0053] A further improvement is that, when the contrast of the photoresist pattern is lower than a required value, the contrast of the photoresist pattern is improved by reducing the ratio of the PAG molecules to the PDQ molecules and setting the ratio of the PAG molecules to the PDQ molecules to be less than 1.
[0054] When the sensitivity of the photoresist in the exposure process is lower than a required value, the sensitivity of the photoresist is improved by increasing the ratio of the PAG molecules to the PDQ molecules and setting the ratio of the PAG molecules to the PDQ molecules to be greater than 1.
[0055] The present application contains a linker with a carbon-oxygen chemical bond or a carbon-nitrogen chemical bond which is easy to synthesize, such as a polyol ether, which is advantageous for synthesizing multiple PAG molecules and PDQ molecules on one linker and can set the ratio of PAG molecules and PDQ molecules as required, can synthesize a bifunctional molecular group structure that meets various PAG and PDQ ratios and types, can increase the degree of diversification of additives in the photoresist, thereby ensuring the uniformity of PAG and PDQ in the photoresist, ensuring the uniformity of line width and roughness of the photoresist, while meeting the different needs of users for the contrast and photosensitivity of the chemically amplified resist. BRIEF DESCRIPTION OF DRAWINGS
[0056] The present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments:
[0057] Figures 1A-1D is a schematic diagram of the action mechanism of PAG in the photoresist in each step of the existing photoresist process;
[0058] Figures 2A-2C is a schematic diagram of the action mechanism of PDQ in the photoresist in each step of the existing photoresist process;
[0059] Figure 3 is a distribution curve of the acid concentration and base concentration in the exposed area and non-exposed area of the existing photoresist process after mixing PDQ;
[0060] Figure 4 is a schematic diagram of the mixing of PAG and PDQ molecules in the existing photoresist that uses a mixture of PAG and PDQ;
[0061] Figure 5 is a schematic diagram of the mixing of PAG and PDQ molecules in the existing photoresist that uses a bifunctional molecular group synthesized from PAG and PDQ;
[0062] Figure 6A is a schematic diagram of one structure of the bifunctional molecular group structure for photoresist in the embodiment of the present application in the photoresist;
[0063] Figure 6B is a schematic diagram of another structure of the bifunctional molecular group structure for photoresist in the embodiment of the present application in the photoresist;
[0064] Figure 7A is a comparison diagram of the line width roughness (LWR) / line edge roughness (LER) effect improvement of the pattern obtained by using the existing photoresist for photoresist and the pattern obtained by using the photoresist of the embodiment of the present application for photoresist;
[0065] Figure 7B is a comparison diagram of the line width uniformity (CDU) effect improvement of the pattern obtained by using the existing photoresist for photoresist and the pattern obtained by using the photoresist of the embodiment of the present application for photoresist;
[0066] Figure 8 is a comparison curve of the dissolution rate of the bifunctional molecular cluster structure for photoresist according to an embodiment of the present application with different contents of PDQ varying with exposure dose;
[0067] Figure 9 is a comparison curve of the residual photoresist thickness of the bifunctional molecular cluster structure for photoresist according to an embodiment of the present application with different contents of PAG varying with exposure dose. DETAILED DESCRIPTION
[0068] The bifunctional molecular cluster structure for photoresist according to an embodiment of the present application comprises a linker, a PAG molecule and a PDQ molecule.
[0069] The linker contains a carbon-oxygen chemical bond or a carbon-nitrogen chemical bond.
[0070] A number of PAG molecules and PDQ molecules are simultaneously synthesized on each linker in a proportion, and the total number of the PAG molecules and the PDQ molecules is more than 3.
[0071] The PAG molecules are synthesized on the linker through the carbon-oxygen chemical bond.
[0072] The PDQ molecules are synthesized on the linker through the carbon-nitrogen chemical bond.
[0073] In the embodiment of the present application, the linker comprises a polyol ether.
[0074] The polyol ether comprises glycerol ether or butanetetrol ether.
[0075] In some embodiments, the linker is glycerol ether, and the molecular structure of the glycerol ether is:
[0076]
[0077] R1, R2 and R3 in the molecular formula (1) represent three groups of the glycerol ether.
[0078] In the bifunctional molecular cluster structure, the PAG molecules are synthesized at one or two positions of R1, R2 and R3, and the types of the PAG molecules at different positions are the same or different.
[0079] The PDQ molecules are synthesized at the positions of R1, R2 and R3 which are not synthesized with the PAG molecules, and the types of the PDQ molecules at different positions are the same or different.
[0080] As can be seen from the molecular formula (1), by replacing the three groups of R1, R2 and R3, a total of three PDQ molecules or PAG molecules can be synthesized; according to different proportions, the molecular number ratio of the PAG molecules and the PDQ molecules includes 1:2 and 2:1.
[0081] When the molecular number ratio of the PAG molecules and the PDQ molecules is 1:2, due to the positional symmetry of R1 and R3, according to the positions of the PAG molecules and the PDQ molecules, the bifunctional molecular group structure can be divided into the following two types:
[0082] The first type is 1,3-di-PDQ-2-PAG, and the corresponding molecular structure is:
[0083]
[0084] As can be seen from the molecular formula (5), the PAG molecule replaces the group corresponding to R2, and the PAG molecule and the linker are combined through a carbon-oxygen chemical bond; the PDQ molecule replaces the two groups corresponding to R1 and R3, and the PDQ molecule and the linker are combined through a carbon-nitrogen chemical bond.
[0085] The second type is 1,2-di-PDQ-3-PAG, and the corresponding molecular structure is:
[0086]
[0087] When the molecular number ratio of the PAG molecules and the PDQ molecules is 2:1, due to the positional symmetry of R1 and R3, according to the positions of the PAG molecules and the PDQ molecules, it can be divided into the following two types:
[0088] The first type is 1,3-di-PAG-2-PDQ, and the corresponding molecular structure is:
[0089]
[0090] The second type is 1,2-di-PAG-3-PDQ, and the corresponding molecular structure is:
[0091]
[0092] In some embodiments, the linker is butanetetrol ether, and the molecular structure of the butanetetrol ether is:
[0093]
[0094] R1, R2, R3 and R4 in the molecular formula (2) represent four groups of the butanetetrol ether.
[0095] In the bifunctional molecular structure, the PAG molecules are synthesized at one or two or three of R1, R2, R3 and R4, and the PAG molecules at different positions are the same or different.
[0096] The PDQ molecules are synthesized at positions other than those of the PAG molecules in R1, R2, R3 and R4, and the PDQ molecules at different positions are the same or different.
[0097] The ratio of the PAG molecules to the PDQ molecules is 1:3 or 3:1.
[0098] As shown in formula (2), R1 and R4 of the butanetetrol ether correspond to symmetrical positions, and R2 and R3 correspond to symmetrical positions. When the ratio of the PAG molecules to the PDQ molecules is 1:3, the bifunctional molecular structure is divided into two types according to the positions of the PAG molecules and the PDQ molecules. Specifically, one of R1 or R2 is replaced by the PAG molecule, and the other three groups are replaced by the PDQ molecule based on formula (2). Similarly, when the ratio of the PAG molecules to the PDQ molecules is 3:1, the bifunctional molecular structure is also divided into two types according to the positions of the PAG molecules and the PDQ molecules.
[0099] In the embodiments of the present application, when the bifunctional molecular structure includes two PAG molecules, the two PAG molecules are the same or different. When the bifunctional molecular structure includes two PDQ molecules, the two PDQ molecules are the same or different.
[0100] In some embodiments, the PAG molecule includes bis(cyclohexylsulfonyl)diazomethane or 3-hydroxy-2,5-dioxopyrrol-1-trifluoromethylsulfonate.
[0101] The molecular structure of bis(cyclohexylsulfonyl)diazomethane is as follows:
[0102]
[0103] In some embodiments, the PDQ molecule adopts 1,3-dioxopyrrol-3,4-tetrahydropyrrol-1-trifluoromethylsulfonate, and the molecular structure is as follows:
[0104]
[0105] In the embodiments of the present application, the photoresist includes a bifunctional molecular structure, a polymer resin, an additive and a solvent. The bifunctional molecular structure of the embodiments of the present application can make the PAG molecules and the PDQ molecules in the photoresist uniformly and at a set ratio.
[0106] As Figure 6A shown in FIG. 6, it is a schematic diagram of one structure of the bifunctional molecular cluster structure for photoresist in the photoresist according to the embodiment of the present application; the bifunctional molecular cluster structure 604a with the ratio of the PAG molecule to the PDQ molecule being 1:2 is adopted in the photoresist 601a, and it can be seen that one bifunctional molecular cluster structure 604a includes one PAG molecule 603 and two PDQ molecules 602.
[0107] and Figure 5 compared with the prior art bifunctional molecular cluster structure with the ratio of the PAG molecule to the PDQ molecule being 1:1, the embodiment of the present application can make the ratio of the PAG molecule to the PDQ molecule be 1:2, and the adjustment of the ratio of the PAG molecule to the PDQ molecule is realized.
[0108] As Figure 6B shown in FIG. 7, it is a schematic diagram of another structure of the bifunctional molecular cluster structure for photoresist in the photoresist according to the embodiment of the present application; the bifunctional molecular cluster structure 604b with the ratio of the PAG molecule to the PDQ molecule being 2:1 is adopted in the photoresist 601b, and it can be seen that one bifunctional molecular cluster structure 604b includes two PAG molecules 603 and one PDQ molecule 602.
[0109] The linker containing the carbon-oxygen chemical bond or carbon-nitrogen chemical bond which is easy to synthesize, such as polyol ether, in the embodiment of the present application is beneficial to the synthesis of multiple PAG molecules and PDQ molecules on one linker and can set the ratio of the PAG molecule to the PDQ molecule as required, can synthesize the bifunctional molecular cluster structure meeting multiple PAG and PDQ ratio and type, can increase the diversification degree of the additives in the photoresist, thereby ensuring the uniformity of the PAG and PDQ in the photoresist, ensuring the uniformity of the line width and roughness of the photoresist, and meeting the different requirements of the user on the contrast and photosensitivity of the chemically amplified resist.
[0110] As Figure 7A shown in FIG. 8, it is a comparison diagram of the LWR / LER effect improvement of the pattern obtained by using the prior art photoresist for photoetching and the pattern obtained by using the photoresist according to the embodiment of the present application for photoetching; Figure 7A In FIG. 8, the pattern 701a is obtained by using the prior art photoresist for photoetching, and the pattern 701b is obtained by using the photoresist according to the embodiment of the present application for photoetching, and it can be seen that the edge of the pattern 701b is more flat, while the edge of the pattern 701b fluctuates greatly. Therefore, the embodiment of the present application can improve the LWR and LER.
[0111] As Figure 7B shown in FIG. 9, it is a comparison diagram of the CDU effect improvement of the pattern obtained by using the prior art photoresist for photoetching and the pattern obtained by using the photoresist according to the embodiment of the present application for photoetching;Figure 7B In the diagram, pattern 701c is a pattern obtained by photolithography using existing photoresist, and pattern 701d is a pattern obtained by photolithography using the photoresist of the present invention. It can be seen that the width of each pattern 701c varies greatly, while the width of each pattern 701d is uniform. Therefore, the present invention can improve the CDU effect.
[0112] This invention can improve the effects of LWR, LER, and CDU, and also allows for convenient adjustment of the ratio of PAG molecules and PDQ molecules. This allows the ratio of PAG molecules to PDQ molecules to be set according to the needs of the photoresist during application, thereby improving the photolithography process.
[0113] like Figure 8 The figure shows a comparison curve of the dissolution rate as a function of exposure dose when the PDQ content in the bifunctional molecular cluster structure of the photoresist used in the embodiments of the present invention is different. Figure 8 In the diagram, curve 801 corresponds to the dissolution rate of photoresist with a higher PDQ content as a function of exposure dose; curve 802 corresponds to a PDQ content lower than that of curve 801. It can be seen that curve 801 is steeper than curve 802, therefore, as the PDQ content increases, the dissolution rate of the photoresist becomes more sensitive to changes in exposure dose. Thus, if it is necessary to increase the sensitivity of the photoresist's dissolution rate to changes in exposure dose, only the PDQ content needs to be increased. Furthermore, the ratio of PAG molecules to PDQ molecules in the bifunctional molecular cluster structure can be set according to the required PDQ content.
[0114] like Figure 9 The figure shows a comparison curve of the remaining photoresist thickness as a function of exposure dose when the PAG content in the bifunctional molecular cluster structure of the photoresist used in the embodiments of the present invention is different. Figure 9 In the diagram, curve 803 corresponds to the remaining photoresist thickness as a function of exposure dose for photoresists with higher PAG content; curve 804 corresponds to a PAG content lower than that of curve 803, which corresponds to a PDQ content. It can be seen that curve 803 is steeper than curve 804, therefore, as the PAG content increases, the remaining photoresist thickness becomes more sensitive to changes in exposure dose. Thus, if it is necessary to increase the photosensitivity of the photoresist, only the PAG content needs to be increased, and the ratio of PAG molecules to PDQ molecules in the bifunctional molecular cluster structure can be set according to the required PAG content.
[0115] In this invention, a linker composed of polyol ethers such as glycerol ether and butylene ether is used to connect PAG and PDQ, thereby synthesizing a bifunctional molecular group structure that satisfies various PAG to PDQ ratios and types, thus increasing the diversity of additives.
[0116] The linker in this invention can synthesize multiple PAGs and PDQs into a single molecule according to a specified ratio, ensuring the uniformity of PAGs and PDQs in the photoresist, ensuring the uniformity of the photoresist linewidth and roughness, and simultaneously meeting the different needs of users for chemically amplified photoresist contrast and photosensitivity.
[0117] Existing linkers mix PAG and PDQ in a 1:1 ratio. The linker of this invention can synthesize multiple PAG and PDQ into a single molecule according to a specified ratio, thereby meeting users' different needs for photoresist contrast, stability, and photosensitivity, such as:
[0118] 1. PAG: The bifunctional molecular group with PDQ<1 can increase the ammonia concentration in the unexposed area, continuously neutralize some of the acid, greatly reduce the acid diffusion length, and increase the contrast of the photoresist.
[0119] 2. PAG: Bifunctional molecular groups with PDQ>1 can increase the acid concentration in the exposure area, greatly increasing the acid diffusion length and enhancing the sensitivity of the photoresist, which can be described by contrast curves.
[0120] 3. A good PAG can achieve an optimal balance between solubility, stability, sensitivity and process window. One type of PAG may not be able to meet all the requirements. The embodiments of this invention can add different photoacids according to the desired parameter improvement direction.
[0121] The linker molecule structure of this invention contains easily synthesized chemical bonds such as carbon-oxygen and carbon-nitrogen. The linker molecule structure should have low steric hindrance and contain multiple functional groups, which facilitates the synthesis of multiple PAG and PDQ molecules and also contributes to the stability of bifunctional molecular groups.
[0122] In the method for synthesizing bifunctional molecular cluster structures for photoresists in this embodiment of the invention, the carbon-oxidation chemical bonds and the carbon-nitrogen chemical bonds are obtained through a substitution reaction.
[0123] The method of using the photoresist with a bifunctional molecular cluster structure in this embodiment of the invention includes the following steps:
[0124] Photoresist is applied to the surface of the wafer.
[0125] Perform pre-baking.
[0126] Exposure and development are performed to form a photoresist pattern. During the exposure, the PAG molecules in the exposed area release H+ and form acid, while the PDQ molecules lose their basicity.
[0127] Post-baking is then performed. Post-baking eliminates the standing wave effect of the photoresist, resulting in a better photoresist morphology.
[0128] During the post-baking process, the photoresist in the exposed area decomposes under the catalysis of acid and generates new acid; the PDQ molecules in the unexposed area neutralize the acid that diffuses into the unexposed area.
[0129] When the contrast of the photoresist pattern is lower than the required value, the contrast of the photoresist pattern is improved by reducing the ratio of PAG molecules and PDQ molecules and setting the ratio of PAG molecules and PDQ molecules to be less than 1.
[0130] When the sensitivity of the photoresist is lower than the required value during the exposure process, the sensitivity of the photoresist is improved by increasing the ratio of PAG molecules and PDQ molecules and setting the ratio of PAG molecules to PDQ molecules to be greater than 1.
[0131] The present invention has been described in detail above through specific embodiments, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.
Claims
1. A bifunctional molecular cluster structure for photoresist, characterized in that, include: Linkers, PAG molecules, and PDQ molecules; The linker contains a carbon-oxidation chemical bond or a carbon-nitrogen chemical bond; Each of the linkers is simultaneously synthesized with a proportional number of PAG molecules and PDQ molecules, and the total number of PAG molecules and PDQ molecules is more than 3. The PAG molecule is synthesized on the linker via the carbon-oxidation chemical bond; The PDQ molecule is synthesized on the linker via the carbon-nitrogen chemical bond.
2. The bifunctional molecular cluster structure for photoresist as described in claim 1, characterized in that: The linker includes a polyol ether.
3. The bifunctional molecular cluster structure for photoresist as described in claim 2, characterized in that: The polyol ethers include glycerol ethers or butanethyl alcohol ethers.
4. The bifunctional molecular cluster structure for photoresist as described in claim 3, characterized in that: The molecular structure of the glycerol ether is as follows: In molecular formula (1), R1, R2, and R3 represent the three groups of the glycerol ether. In the bifunctional molecular group structure, the PAG molecules are synthesized at one or two positions in R1, R2 and R3, and the types of PAG molecules at different positions may be the same or different. The PDQ molecules are synthesized at the positions in R1, R2, and R3 where the PAG molecules were not synthesized, and the types of PDQ molecules at different positions may be the same or different. The ratio of PAG molecules to PDQ molecules is 1:2 or 2:
1.
5. The bifunctional molecular cluster structure for photoresist as described in claim 3, characterized in that: The molecular structure of the butanetetraol ether is as follows: In molecular formula (2), R1, R2, R3 and R4 represent the four groups of the butanetetraol ether; In the bifunctional molecular group structure, the PAG molecules are synthesized at one, two, or three positions in R1, R2, R3, and R4, and the types of PAG molecules at different positions may be the same or different. The PDQ molecules are synthesized at the positions in R1, R2, R3, and R4 where the PAG molecules were not synthesized, and the types of PDQ molecules at different positions may be the same or different. The ratio of PAG molecules to PDQ molecules is 1:3 or 3:
1.
6. The bifunctional molecular cluster structure for photoresist as described in claim 1, characterized in that: The PAG molecule includes di(cyclohexylsulfonyl)diazomethane or 3-hydroxy-2,5-dioxopyrrole-1-trifluoromethylsulfonate. The molecular structure of di(cyclohexylsulfonyl)diazomethane is:
7. The bifunctional molecular cluster structure for photoresist as described in claim 1, characterized in that: The PDQ molecule is 1,3-dioxopyrrolo-3,4-tetrahydropyrrole-1-trifluoromethylsulfonate, with the following molecular structure:
8. The bifunctional molecular cluster structure for photoresist as described in claim 1, characterized in that: Photoresist comprises a bifunctional molecular structure, a polymer resin, additives, and a solvent.
9. A method for synthesizing a bifunctional molecular cluster structure for photoresist as described in any one of claims 1 to 8, characterized in that: The carbon-oxidation chemical bond and the carbon-nitrogen chemical bond are obtained through a substitution reaction.
10. A method of using a photoresist employing the bifunctional molecular cluster structure for photoresist as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Photoresist is applied to the surface of the wafer; Pre-baking; Exposure and development are performed to form a photoresist pattern; Perform post-baking.
11. The method of using a photoresist with a bifunctional molecular cluster structure as described in claim 10, characterized in that: During the exposure, the PAG molecules in the exposed area release H+ and form acid, while the PDQ molecules lose their basicity.
12. The method of using a photoresist with a bifunctional molecular cluster structure as described in claim 11, characterized in that: During the post-baking process, the photoresist in the exposed area decomposes under the catalysis of acid and generates new acid; the PDQ molecules in the unexposed area neutralize the acid that diffuses into the unexposed area.
13. The method of using a photoresist with a bifunctional molecular cluster structure as described in claim 12, characterized in that: When the contrast of the photoresist pattern is lower than the required value, the contrast of the photoresist pattern is improved by reducing the ratio of PAG molecules and PDQ molecules and setting the ratio of PAG molecules and PDQ molecules to less than 1. When the sensitivity of the photoresist is lower than the required value during the exposure process, the sensitivity of the photoresist is improved by increasing the ratio of PAG molecules and PDQ molecules and setting the ratio of PAG molecules to PDQ molecules to be greater than 1.