RAFT (reversible addition-fragmentation chain transfer) polymer resin as well as preparation method and application thereof

Abstract

The invention provides RAFT (reversible addition-fragmentation chain transfer) polymer resin as well as a preparation method and application thereof. The preparation method comprises the following step: carrying out free radical reaction on an RAFT polymer and a monomer under the action of a free radical type initiator. According to the preparation method of the RAFT polymer resin, provided by the invention, a coupling phenomenon is avoided while a terminal thiocarbonyl group is completely removed, so that the performance of the resin is kept stable; the prepared resin is narrow in molecular weight distribution; the method has the advantages of simple steps, mild reaction temperature, short reaction time, no need of pressurization in the reaction process and low requirements on equipment.

Description

Technical Field

[0001] The invention relates to the technical field of polymer synthesis, in particular to a RAFT polymer resin and a preparation method and application thereof. Background Art

[0002] Chemically amplified photoresist (CAR) was proposed by Ito and Wilson in 1982 and has become the basis for the fabrication of current and future integrated circuit devices due to its excellent patterning performance and high sensitivity. In the past decade, living / controlled radical polymerization, such as atom transfer radical polymerization (ATRP), nitroxide-mediated radical polymerization (NMP), and reversible addition-fragmentation chain transfer (RAFT), has rapidly developed into an efficient synthetic method for preparing polymers with various specific structures, low polydispersity, and controllable molecular weight.

[0003] Among them, the RAFT polymerization method was proposed by Moad, Rizzardo, and Thang in 1998, using thiocarbonyl organic compounds as chain transfer agents. It has the advantages of (1) a wide range of monomers, including styrenes, acrylates, and vinyl monomers; (2) strong molecular design capabilities, which can be used to prepare block, graft and star copolymers; (3) good control over the molecular weight of the polymer. Generally speaking, RAFT polymerization is to insert repeating units between the CS bonds of the chain transfer agent so that the final polymer contains thiocarbonyl groups (S=C(Z)-S-). The sulfur-containing groups of the RAFT chain transfer agent will affect the performance of the polymer due to problems such as color and gas volatility. These shortcomings greatly reduce the industrial application value of the polymer; in addition, sometimes we need to intentionally change the terminal groups to make them have functional terminal groups for subsequent treatment. At present, this method has been widely used in the synthesis of block, graft and other polymers. Therefore, it is of great significance to treat the terminal end groups of RAFT polymers.

[0004] The RAFT end group removal reaction has the following methods: reaction with nucleophilic reagents, reaction with oxides, free radical induced reduction method, thermal decomposition method, etc. Among them, the most commonly used method with the best industrialization possibility is free radical induced reduction method. The free radical induced reduction method currently used uses initiators such as azobisisobutyronitrile (azo) or dodecyl peroxide (peroxide) to initiate the break of the disulfide or trisulfide bond at the end of the polymer, and then reconnects the terminal group after the break of azobisisobutyronitrile (AIBN) or dodecyl peroxide (LPO) to achieve the conversion of sulfur-containing groups.

[0005] However, in the prior art, after synthesizing styrene polymers by RAFT polymerization, when AIBN is used alone as a free radical generator to remove the end groups, the sulfur-containing groups cannot be completely removed 100%, and when a peroxide such as dibenzoyl peroxide (BPO) is used as a free radical generator, a very serious coupling phenomenon will be caused, which is manifested in the appearance of a double peak in gel permeation chromatography (GPC). Even after using a mixed system of AIBN and LPO, although the sulfur-containing groups can be completely removed, the shoulder peak in GPC still exists, and the coupling generation can only be suppressed to the greatest extent, such as Fig.12 For photoresist resin, these shoulder peaks will greatly affect its subsequent photolithography performance, so it is necessary to completely avoid the coupling phenomenon when removing the end group and completely eliminate the shoulder peaks.

[0006] Removing the terminal sulfur-containing groups of RAFT polymers containing styrene groups is beneficial to improving the performance of photoresist resins and is of great significance. However, no satisfactory terminal group removal method has been found in the prior art, which can completely remove the sulfur-containing groups of styrene-based RAFT polymers without causing coupling. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a RAFT polymer resin and a preparation method and use thereof, so as to solve the problems in the prior art.

[0008] To achieve the above objectives and other related objectives, the present invention is achieved through the following technical solutions.

[0009] The invention provides a method for preparing a RAFT polymer resin. The method comprises the following steps: subjecting a RAFT polymer and a monomer to a free radical reaction under the action of a free radical initiator.

[0010] Preferably, the RAFT polymer is a polymer formed by a RAFT reaction using at least a styrene derivative as a raw material.

[0011] Preferably, the RAFT polymer further uses a thiocarbonylthio compound as a chain transfer agent in the RAFT reaction.

[0012] Preferably, the monomer is selected from one or both of 1,1-diphenylethylene and α-methylstyrene.

[0013] Preferably, the free radical initiator is selected from one or both of an azo initiator and a peroxide initiator.

[0014] More preferably, the azo initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile or dimethyl azobisisobutyrate.

[0015] More preferably, the peroxide initiator is selected from one or more of benzoyl peroxide, dodecyl peroxide, tert-butyl benzoyl peroxide or methyl ethyl ketone peroxide.

[0016] More preferably, the molar ratio of the terminal thiocarbonyl group in the RAFT polymer to the azo initiator is 1:(10-40), such as 1:10, 1:15, 1:20, 1:23, 1:30, 1:35 or 1:40.

[0017] More preferably, the molar ratio of the terminal thiocarbonyl group in the RAFT polymer to the peroxide initiator is 1:(1-4), such as 1:1.0, 1:1.5, 1:2, 1:2.3, 1:2.5, 1:2.6, 1:3.0, 1:3.6 or 1:4.0.

[0018] More preferably, the free radical initiator is a mixture of an azo initiator and a peroxide initiator, and the ratio of the azo initiator to the peroxide initiator is (10-40): (1-4). More preferably, the free radical initiator is a mixture of an azo initiator and a peroxide initiator, and the ratio of the azo initiator to the peroxide initiator is (10-30): (1.5-2).

[0019] Preferably, the amount of the monomer is at least 15 times the molar number of terminal thiocarbonyl groups and in the RAFT polymer. More preferably, the amount of the monomer is at least 25 times the molar number of terminal thiocarbonyl groups and in the RAFT polymer. Preferably, the amount of the monomer is at least 35 times the molar number of terminal thiocarbonyl groups and in the RAFT polymer. Preferably, the amount of the monomer is at least 45 times the molar number of terminal thiocarbonyl groups and in the RAFT polymer. More preferably, the amount of the monomer is at least 50 times the molar number of terminal thiocarbonyl groups and in the RAFT polymer. Most preferably, the amount of the monomer is 50 to 200 times the molar number of terminal thiocarbonyl groups and in the RAFT polymer.

[0020] Preferably, the styrene derivative is p-acetoxystyrene.

[0021] Preferably, the free radical reaction system further contains a solvent, and the solvent is one or more selected from propylene glycol methyl ether acetate, tetrahydrofuran, ethyl acetate or methanol.

[0022] More preferably, the content of the RAFT polymer in the solvent is 5 wt%-10 wt%, such as 5 wt%, 7 wt%, or 10 wt%.

[0023] Preferably, the free radical reaction temperature is 70°C to 100°C, such as 70°C, 80°C, 85°C, 90°C, or 100°C.

[0024] Preferably, the free radical reaction time is 3 h to 9 h.

[0025] Preferably, the inert gas is selected from one or more of nitrogen or rare gases.

[0026] Preferably, in the free radical reaction system, the reactants are mixed before the free radical reaction, and the mixing temperature is 15°C to 35°C.

[0027] More preferably, the mixing is carried out by stirring.

[0028] More preferably, the mixing time is 30 min to 60 min.

[0029] Preferably, the preparation method further comprises a post-processing step, wherein the post-processing step comprises: using n-hexane for precipitation, followed by filtering and drying. The filtering is to obtain a precipitate by solid-liquid separation. The drying is to use a vacuum drying oven at 40 to 60°C to dry the precipitate.

[0030] The invention also discloses the RAFT polymer resin obtained by the preparation method.

[0031] Preferably, the molecular weight distribution index of the RAFT polymer resin is 1 to 1.2.

[0032] The invention also discloses the use of the RAFT polymer resin as a photoresist.

[0033] The present invention has the following beneficial effects:

[0034] (1) While completely removing the terminal thiocarbonyl group, no coupling occurs, so that the resin performance remains stable;

[0035] (2) The prepared resin has a narrow molecular weight distribution;

[0036] (3) The steps are simple, the reaction temperature is mild, the reaction time is short, the reaction process does not require pressurization, and the equipment requirements are not high. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Shown are the SEC elution curve and molecular weight distribution of the RAFT polymer resin in Example 1 of the present invention.

[0038] Figure 2 Shown are the SEC elution curve and molecular weight distribution diagram of the RAFT polymer resin in Example 2 of the present invention.

[0039] Figure 3Shown is the SEC elution curve and molecular weight distribution diagram of the RAFT polymer resin in Example 3 of the present invention.

[0040] Figure 4 Shown are the SEC elution curve and molecular weight distribution of the RAFT polymer resin in Example 4 of the present invention.

[0041] Figure 5 Shown is the SEC elution curve and molecular weight distribution diagram of the RAFT polymer resin in Example 5 of the present invention.

[0042] Figure 6 It shows the SEC elution curve and molecular weight distribution of the RAFT polymer resin in Comparative Example 1 of the present invention.

[0043] Figure 7 It shows the SEC elution curve and molecular weight distribution of the RAFT polymer resin in Comparative Example 2 of the present invention.

[0044] Figure 8 It shows the SEC elution curve and molecular weight distribution of the RAFT polymer resin in Comparative Example 3 of the present invention.

[0045] Fig. 9 It shows the SEC elution curve and molecular weight distribution of the RAFT polymer resin in Comparative Example 4 of the present invention.

[0046] Fig.10 It shows the SEC elution curve and molecular weight distribution of the RAFT polymer resin in Comparative Example 5 of the present invention.

[0047] Fig.11 It shows the SEC elution curve and molecular weight distribution of the RAFT polymer resin in Comparative Example 6 of the present invention.

[0048] Fig.12 It shows the SEC elution curve of the product after RAFT end group removal reaction in the background technology of the present invention. DETAILED DESCRIPTION

[0049] 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.

[0050] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0051] Furthermore, it should be understood that one or more method steps mentioned in the present invention do not exclude the possibility that other method steps may exist before or after the combined steps or that other method steps may be inserted between these explicitly mentioned steps, unless otherwise stated.

[0052] The preparation method of the RAFT polymer of the raw materials used in the present application is: dissolving p-acetoxystyrene, a chain transfer agent, and an initiator in a solvent, and heating to 80-120° C. for reaction under a nitrogen atmosphere.

[0053] Preferably, the chain transfer agent is a trithiocarbonate.

[0054] Preferably, the initiator is azobisisobutyronitrile.

[0055] After the reaction, the reaction solution was added into n-hexane, filtered and dried to obtain a precipitated RAFT polymer.

[0056] The molar ratio of acetoxystyrene, chain transfer agent and initiator is (40-60):1:(0.05-0.2).

[0057] When the terminal thiocarbonyl group of the RAFT polymer is removed, the RAFT polymer before and after the removal is analyzed by gel permeation chromatography (GPC) to obtain a SEC elution curve diagram to determine whether coupling occurs while removing the terminal thiocarbonyl group of the RAFT polymer.

[0058] Gel permeation chromatography instrument and analysis conditions:

[0059] Instrument: Waters 2695 gel permeation chromatograph;

[0060] Analysis conditions: Using a differential detector (model 2414), the relative molecular weight separation range of HR1, HR3 and HR4 columns is 582-328000, tetrahydrofuran is used as the mobile phase, the flow rate is 0.8-1.2 mL / min, and the measurement is performed at 30-40°C. The molecular weight is calibrated with polystyrene.

[0061] Elemental analysis was performed before and after the removal of the terminal thiocarbonyl groups of the RAFT polymer to determine whether the terminal thiocarbonyl groups of the RAFT polymer were completely removed. The elemental analysis was performed using an Elementar Unicube elemental analyzer in the CHNS mode.

[0062] Example 1

[0063] This embodiment provides a method for preparing a RAFT polymer resin, and the specific steps are as follows:

[0064] Dissolve poly(p-acetoxystyrene) with an average molecular weight of 30,000 in propylene glycol methyl ether acetate, add azobisisobutyronitrile and benzoyl peroxide under a nitrogen atmosphere, then add 1,1-stilbene and stir evenly; heat the solution to 85°C and continue stirring for 3 hours to terminate the reaction. Add n-hexane to the reaction solution to precipitate, then filter and dry in vacuum at 50°C.

[0065] The concentration of poly(p-acetoxystyrene) in propylene glycol methyl ether acetate is 10%, the molar ratio of the terminal thiocarbonyl group in poly(p-acetoxystyrene) to azobisisobutyronitrile is 1:30, the molar ratio of the terminal thiocarbonyl group in poly(p-acetoxystyrene) to benzoyl peroxide is 1:1.5, and the molar ratio of the terminal thiocarbonyl group in poly(p-acetoxystyrene) to 1,1-stilbene is 1:120.

[0066] The RAFT polymer resin in Example 1 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Figure 1 shown.

[0067] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin in Example 1. The analysis results are shown in Tables 1 and 2.

[0068] Example 2

[0069] The present embodiment provides a method for preparing a RAFT polymer resin, which is different from that of Example 1 in that the reaction temperature is 80° C., the reaction time is 5 h, the molar ratio of the terminal thiocarbonyl group in poly(p-acetoxystyrene) to azobisisobutyronitrile is 1:15, the molar ratio of the terminal thiocarbonyl group in poly(p-acetoxystyrene) to benzoyl peroxide is 1:3.6, and the molar ratio of the terminal thiocarbonyl group in poly(p-acetoxystyrene) to 1,1-diphenylethylene is 1:180.

[0070] The RAFT polymer resin in Example 2 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Figure 2 shown.

[0071] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin in Example 2. The analysis results are shown in Tables 1 and 3.

[0072] Example 3

[0073] The present embodiment provides a method for preparing a RAFT polymer resin, which is different from that of Example 1 in that the reaction temperature is 90° C., the reaction time is 5 h, the molar ratio of the terminal thiocarbonyl group in poly(p-acetoxystyrene) to azobisisobutyronitrile is 1:20, the molar ratio of the terminal thiocarbonyl group in poly(p-acetoxystyrene) to benzoyl peroxide is 1:2, and the molar ratio of the terminal thiocarbonyl group in poly(p-acetoxystyrene) to 1,1-stilbene is 1:50.

[0074] The RAFT polymer resin in Example 3 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Figure 3 shown.

[0075] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin in Example 3. The analysis results are shown in Tables 1 and 3.

[0076] Example 4

[0077] This embodiment provides a method for preparing a RAFT polymer resin, which is different from that of Embodiment 3 in that the reaction temperature is 100° C., and the molar ratio of the terminal thiocarbonyl group to 1,1-diphenylethylene in poly(p-acetoxystyrene) is 1:100.

[0078] The RAFT polymer resin in Example 4 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Figure 4 shown.

[0079] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin in Example 4. The analysis results are shown in Tables 1 and 3.

[0080] Example 5

[0081] This embodiment provides a method for preparing a RAFT polymer resin, which is different from Example 3 in that the reaction temperature is 100° C., the concentration of poly(p-acetoxystyrene) in propylene glycol methyl ether acetate is 5%, and the molar ratio of terminal thiocarbonyl groups to 1,1-diphenylethylene in poly(p-acetoxystyrene) is 1:200.

[0082] The RAFT polymer resin in Example 5 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Figure 5 shown.

[0083] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin in Example 5. The analysis results are shown in Tables 1 and 3.

[0084] Comparative Example 1

[0085] This comparative example is a comparative example of Example 3, except that the molar ratio of the terminal thiocarbonyl group to 1,1-diphenylethylene in the poly(p-acetoxystyrene) is 1:0.1.

[0086] The RAFT polymer resin in Comparative Example 1 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Figure 6 shown.

[0087] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin of Comparative Example 1. The analysis results are shown in Tables 1 and 3.

[0088] Comparative Example 2

[0089] This comparative example is a comparative example of Example 3, except that the molar ratio of the terminal thiocarbonyl group to 1,1-diphenylethylene in the poly(p-acetoxystyrene) is 1:1.

[0090] The RAFT polymer resin in Comparative Example 2 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Figure 7 shown.

[0091] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin of Comparative Example 2. The analysis results are shown in Tables 1 and 3.

[0092] Comparative Example 3

[0093] This comparative example is a comparative example of Example 3, except that the molar ratio of the terminal thiocarbonyl group to 1,1-diphenylethylene in the poly(p-acetoxystyrene) is 1:10.

[0094] The RAFT polymer resin in Comparative Example 3 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Figure 8 shown.

[0095] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin of Comparative Example 3. The analysis results are shown in Tables 1 and 2.

[0096] Comparative Example 4

[0097] This comparative example is a comparative example of Example 3, except that 1,1-diphenylethylene is not added to the reaction system.

[0098] The RAFT polymer resin in Comparative Example 4 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Fig. 9 shown.

[0099] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin of Comparative Example 4. The analysis results are shown in Tables 1 and 3.

[0100] Comparative Example 5

[0101] This comparative example is the comparative example of Example 3, except that 1,1-diphenylethylene is not added to the reaction system, and benzoyl peroxide is replaced by dodecyl peroxide.

[0102] The RAFT polymer resin in Comparative Example 5 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Fig.10 shown.

[0103] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin of Comparative Example 5. The analysis results are shown in Tables 1 and 3.

[0104] Comparative Example 6

[0105] This comparative example is a comparative example of Example 3, except that benzoyl peroxide and 1,1-diphenylethylene are not added to the reaction system.

[0106] The RAFT polymer resin in Comparative Example 6 was subjected to GPC analysis, and the SEC elution curve and molecular weight distribution were as follows: Fig.11 shown.

[0107] Elemental analysis was performed on the raw material poly(p-acetoxystyrene) and the product RAFT polymer resin of Comparative Example 6. The analysis results are shown in Tables 1 and 3.

[0108] Table 1 Elemental analysis of poly(p-acetoxystyrene)

[0109] element S(％) N(％) C(％) H(％) Poly(p-acetoxystyrene) 0.159 0.77 70.91 5.951

[0110] Table 2 Elemental analysis of RAFT polymer resins

[0111] element S(％) N(％) C(％) H(％) Example 1 0.000 0.16 73.99 5.727

[0112] Table 3 Elemental analysis of RAFT polymer resins

[0113] element S(％) Example 2 0.000 Example 3 0.000 Example 4 0.000 Example 5 0.000 Comparative Example 1 0.000 Comparative Example 2 0.000 Comparative Example 3 0.000 Comparative Example 4 0.000 Comparative Example 5 0.000 Comparative Example 6 0.105

[0114] According to the GPC spectra and elemental analysis of the RAFT polymer resins prepared in the above examples and comparative examples,

[0115] 1) When the amount of 1,1-diphenylethylene is small, for example, when the amount of 1,1-diphenylethylene is 0.1 times, 1 times, or 10 times the molar number of the terminal thiocarbonyl groups in the RAFT polymer, although the sulfur-containing groups can be completely removed, coupling phenomenon will occur, as shown in the corresponding comparative examples 1, 2, and 3. Figures 6 to 8 Middle chromatogram curve;

[0116] 2) If only a mixed system of azo initiators and peroxide initiators is used, although the sulfur-containing groups can be completely removed, such as in Comparative Examples 4 and 5, the shoulder peak on the SEC elution curve still exists, and the coupling phenomenon still exists, such as Fig. 9 and 10 As shown in the chromatogram curve;

[0117] 3) As shown in Comparative Example 6, only using azo initiators cannot completely remove the sulfur-containing groups and will also cause coupling phenomena.

[0118] 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 preparing a RAFT polymer resin, the method comprising the following steps: subjecting a RAFT polymer and a monomer to a free radical reaction under the action of a free radical initiator.

2. The preparation method according to claim 1, characterized in that: The RAFT polymer is a polymer formed by a RAFT reaction using at least a styrene derivative as a raw material; and / or, the RAFT polymer further uses a thiocarbonylthio compound as a chain transfer agent in the RAFT reaction; And / or, the monomer is selected from one or both of 1,1-diphenylethylene or α-methylstyrene; And / or, the free radical reaction system further comprises a solvent, and the solvent is one or more selected from propylene glycol methyl ether acetate, tetrahydrofuran, ethyl acetate or methanol.

3. The preparation method according to claim 1, characterized in that: The free radical initiator is selected from one or both of an azo initiator and a peroxide initiator.

4. The preparation method according to claim 3, characterized in that: The azo initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile or dimethyl azobisisobutyrate; And / or, the peroxide initiator is selected from one or more of benzoyl peroxide, dodecyl peroxide, tert-butyl benzoyl peroxide or methyl ethyl ketone peroxide; And / or, the molar ratio of the terminal thiocarbonyl group in the RAFT polymer to the azo initiator is 1: (10～40)； And / or, the molar ratio of the terminal thiocarbonyl group in the RAFT polymer to the peroxide initiator is 1: (1～4)。 5. The preparation method according to claim 2, characterized in that: The amount of the monomer is at least 15 times the molar number of the terminal thiocarbonyl groups in the RAFT polymer; And / or, the styrene derivative is p-acetoxystyrene.

6. The preparation method according to claim 2, characterized in that: The content of the RAFT polymer in the solvent is 5 wt%-10 wt%.

7. The preparation method according to claim 1, characterized in that: The free radical reaction temperature is 70℃~100℃; And / or, the preparation method further comprises a post-processing step, wherein the post-processing step comprises: precipitation using n-hexane, followed by filtering and drying.

8. A RAFT polymer resin obtained by the preparation method according to any one of claims 1 to 7.

9. The RAFT polymer resin according to claim 8, characterized in that The molecular weight distribution index of the RAFT polymer resin is 1 to 1.

2.

10. Use of a RAFT polymer resin as claimed in any one of claims 8 or 9 as a photoresist.

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