Patent Application
20240302749
The present disclosure relates to a resin and an ArF dry photoresist composition containing same, and use thereof.
Lithography refers to a pattern micromachining technique that transfers a pattern designed on a mask onto a substrate by means of exposure, development, etching and other processes using the chemical sensitivity of a lithographic material (specifically a photoresist) under the action of visible light, ultraviolet light, electron beams, etc. A lithographic material (specifically a photoresist), also known as a photoresist, is the most critical functional chemical material involved in lithography, the main components thereof being a resin, a photo acid generator (PAG), and corresponding additives and solvents. A photoacid generator is a photosensitive compound, which is decomposed under the illumination to produce an acid, and the acid thus produced can allow a decomposition or cross-linking reaction of an acid-sensitive resin, thereby increasing the dissolution contrast between an illuminated portion and a non-illuminated portion in a developing solution and being applicable to the technical field of pattern micromachining.
The three important parameters of a photoresist, including resolution, sensitivity and line width roughness, determine the process window of the photoresist during chip manufacturing. With the continuous improvement of the performance of semiconductor chips, the integration level of integrated circuits increases exponentially, and patterns in integrated circuits become smaller and smaller. In order to fabricate smaller patterns, it is necessary to improve the above-mentioned three performance indexes of a photoresist. According to the Rayleigh equation, the resolution of a photoresist can be improved by using a short-wavelength light source in a photolithography process. The wavelength of a light source used in a photolithography process has developed from 365 nm (I-line) to 248 nm (KrF), 193 nm (ArF) and 13 nm (EUV). In order to improve the sensitivity of a photoresist, a chemically amplified photosensitive resin is currently used in mainstream KrF, ArF and EUV photoresists. Therefore, a photoacid generator matched with a chemically amplified photosensitive resin is widely used in high-end photoresists.
With the gradual development of a photolithography process to a 193-nm dry exposure process, the complexity of the process increases, and there are increasingly higher requirements on a resist (i.e. photoresist). It has become an urgent problem to be solved in the industry to develop a resist that can improve the resolution, sensitivity and line width roughness of a photoresist.
The technical problem addressed by the present disclosure is to overcome the deficiency of limited resin types available for use in photoresists. To this end, provided are a resin, and an ArF dry photoresist composition containing same, and use thereof. The photoresist containing a resin of the present disclosure has the advantages of high resolution, high photosensitivity, and low line width roughness.
The present disclosure provides a resin obtained by the following polymerizing monomers in parts by weight: 40 to 47.5 parts of monomer A, 0.5 to 5 parts of monomer B, 0.25 to 2.5 parts of monomer C, and 0.25 to 2.5 parts of monomer D;
In some embodiments, for R1, the C1-10 alkyl is C1-5 alkyl, preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl, such as methyl.
In some embodiments, for R2, the C1-10 alkyl is C1-5 alkyl, preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl, such as methyl.
In some embodiments, for R3, the C1-10 alkyl is C1-5 alkyl, preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl, such as methyl.
In some embodiments, for R4, the C2-4 alkenyl is C2-3 alkenyl, preferably ethenyl or isopropenyl, such as isopropenyl.
In some embodiments, for R5, the C1-5 alkyl is preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl, such as methyl.
In some embodiments, the n is 2.
In some embodiments, R2 is C1-10 alkyl.
In some embodiments, R5 and R6 are independently C1-10 alkyl.
In some embodiments, the monomer A is
In some embodiments, the monomer B is
In some embodiments, the monomer Cis
In some embodiments, the monomer D is
In some embodiments, the weight average molecular weight (Mw) of the resin is 5,000 to 10,000, such as 5,516 to 9,209 (e.g., 6,873, 7,199, 5,956, or 6,577).
In some embodiments, the molecular weight distribution coefficient of the resin is 1.8 to 2.0 (e.g., 1.9).
The molecular weight distribution coefficient refers to the ratio of the weight average molecular weight to the number average molecular weight of the resin.
In some embodiments, the monomer A is 42.5 to 46 parts by weight, such as 45 parts by weight.
In some embodiments, the monomer A is 42.5 to 45 parts by weight.
In some embodiments, the monomer B is 2.5 to 5 parts by weight (such as 4 parts by weight).
In some embodiments, the monomer C is 0.25 to 1.75 parts by weight (such as 0.5, 0.75, or 1.25 parts by weight).
In some embodiments, the monomer C is 0.5 to 1.25 parts by weight (such as 0.75 parts by weight).
In some embodiments, the monomer D is 0.5 to 1.75 parts by weight (such as 0.75, or 1.25 parts by weight).
In some embodiments, the monomer D is 0.5 to 1.25 parts by weight (such as 0.75 parts by weight).
In some embodiments, the monomer A is
and is 42.5 to 46 parts by weight;
and is 2.5 to 5 parts by weight;
and is 0.25 to 1.25 parts by weight;
and is 0.5 to 1.75 parts by weight.
In some embodiments, the monomer A is
and is 42.5 to 45 parts by weight;
and is 2.5 to 5 parts by weight;
and is 0.5 to 1.25 parts by weight;
and is 0.5 to 1.25 parts by weight.
In some embodiments, the resin is any one of resins 1 to 6 obtained by polymerizing the following monomers in parts by weight:
the monomer B is
the monomer C
is the monomer D is
In the resin 1, the weight average molecular weight of the resin can be 6873; the molecular weight distribution coefficient of the resin can be 2.
In the resin 2, the weight average molecular weight of the resin can be 9209; the molecular weight distribution coefficient of the resin can be 1.8.
In the resin 3, the weight average molecular weight of the resin can be 7199; the molecular weight distribution coefficient of the resin can be 2.
In the resin 4, the weight average molecular weight of the resin can be 5956; the molecular weight distribution coefficient of the resin can be 1.9.
In the resin 5, the weight average molecular weight of the resin can be 6577; the molecular weight distribution coefficient of the resin can be 2.
In the resin 6, the weight average molecular weight of the resin can be 5516; the molecular weight distribution coefficient of the resin can be 1.5.
The present disclosure further provides a preparation method for the resin, the preparation method comprising the following steps: carrying out a polymerization reaction involving the monomer A in 40 to 47.5 parts by weight, the monomer B in 0.5 to 5 parts by weight, the monomer C in 0.25 to 2.5 parts by weight, and the monomer D in 0.25 to 2.5 parts by weight in an organic solvent to obtain the resin;
R1, R2, R3, R4, R5, R6, and n are as previously defined;
The amount of the monomer A, the monomer B, the monomer C, and the monomer D are as previously described.
The conditions and operations for the polymerization reaction can be those conventional for such reactions in this field. The present disclosure particularly prefers the following conditions and operations:
In the polymerization reaction, the organic solvent is preferably one or more than one of aromatic solvents (e.g., toluene or benzene), ether solvents (e.g., tetrahydrofuran (THF), ether, or dioxane), methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), and γ-butyrolactone, such as propylene glycol monomethyl ether acetate.
The polymerization reaction is preferably initiated in the presence of a free radical initiator or by heating, such as by heating.
When the polymerization reaction is initiated in the presence of a free radical initiator, the free radical initiator is preferably one or more than one of 2,2′-azobisisobutyronitrile (AIBN), 2,2′-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2′-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide.
When the polymerization reaction is initiated by heating, in the polymerization reaction, the temperature of the polymerization reaction is preferably 50 to 150° C., more preferably 60 to 100° C., such as 70° C.
In the polymerization reaction, the duration of the polymerization reaction is preferably 2 to 6 hours, for example, 3 hours.
Preferably, the polymerization reaction comprises the following steps:
In step 2, it is preferable to add the mixture obtained in step 1 to propylene glycol monomethyl ether acetate for polymerization by dropwise addition (dropwise addition rate of 20 to 40 g/hour, such as 30 g/hour).
In the polymerization reaction, for the purpose of molecular weight control, any known chain transfer agents (e.g., dodecanethiol or 2-mercaptoethanol) can be added. The amount of the chain transfer agent added is preferably 0.01 to 10 mol % (the amount of the chain transfer agent can be calculated based on the total molar amount of the monomers to be polymerized).
After the completion of the polymerization reaction, the preferred post-treatment steps for the reaction are as follows: cooling, precipitating the solid (such as by adding methanol to precipitate the solid), filtering, and drying (such as vacuum drying at 40° C. for 24 hours).
The present disclosure further provides a resin prepared by the preparation method as described above.
The present disclosure further provides a photoresist composition prepared from the following raw materials comprising the following components in parts by weight: 75 to 95 parts of a resin, 1.0 to 10 parts of a photoacid generator, 1,000 to 2,000 parts of a solvent, 0.5 to 3.0 part of a quencher, and a surfactant;
In the photoresist composition, the resin is preferably 85 to 95 parts by weight, such as 90 parts by weight.
In the photoresist composition, the resin is preferably resin 1.
In the photoresist composition, the photoacid generator is preferably 3 to 10 parts by weight, such as 5 or 7 parts by weight.
In the photoresist composition, the photoacid generator can be any conventionally used photoacid generator in the art, and preferably is a compound of formula (I):
In the photoresist composition, the solvent is preferably 1,200 to 1,600 parts by weight, such as 1,500 or 1,600 parts by weight.
In the photoresist composition, the solvent can be any known photoacid generator conventionally used in photoresists, especially in chemically amplified photoresist compositions. The solvent can be one or more than one of ketone solvent (e.g., cyclohexanone and/or methyl-2-pentanone), monohydric alcohol solvent (e.g., monohydric alcohol (e.g., 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol), dihydric alcohol solvent (e.g., diacetone alcohol)), ether solvent (e.g., one or more than one of propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether), and ester solvent (e.g., one or more than one of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, methyl lactate, ethyl pyruvate, butyl acetate, 3-methoxypropyl acetate, 3-ethoxypropyl acetate, tert-butyl acetate, tert-butyl propionate, propylene glycol monobutyl ether acetate, and γ-butyrolactone).
More preferably, the solvent can be one or more than one of ketone solvent, ether solvent, and ester solvent, such as one or more than one of cyclohexanone, ethylene glycol monoethyl ether, and γ-butyrolactone.
In the photoresist composition, the quencher is preferably 0.8 to 2 parts by weight, such as 1.5 parts by weight.
In the photoresist composition, the quencher can be any conventionally used quenchers in the art, preferably one or more than one of amine compound (primary, secondary, and tertiary amine compounds, specifically those having hydroxyl, ether, ester, lactone, cyano, or sulfonate ester groups), sulfonate, and carboxylate, more preferably sulfonate, further preferably a compound of formula Q1 and/or formula Q2, still more preferably a compound of formula Q1;
Especially when the photoresist composition further contains alkali-labile components, it is effective to use amine compounds for protection.
In the photoresist composition, the amount of surfactant can be within the conventional range used in those photoresists in the art, with the preferred amount 0.1 to 0.2 parts by weight, such as 0.15 parts.
In the photoresist composition, the surfactant can be any conventionally used surfactant that is insoluble or substantially insoluble in water but soluble in an alkaline developer, and/or that is insoluble or substantially insoluble in both water and an alkaline developer in the art, preferably one or more than one of FC-4430 (purchased from 3M), S-381 (purchased from AGC Seimi Chemical), E1004 (purchased from Air Products), KH-20, and KH-30 (purchased from Asahi Glass), more preferably KH-20 and/or KH-30, still more preferably KH-30.
In some embodiments, in the photoresist composition, the photoacid generator is one or more than one of
In some embodiments, the photoresist composition is prepared from the following raw materials comprising the following components in parts by weight: the resin as described above (including types and amounts of the resin), the photoacid generator as described above (including types and amounts of the photoacid generator), the solvent as described above (including types and amounts of the solvent), the quencher as described above (including types and amounts of the quencher), and the surfactant as described above (including types and amounts of the surfactant).
In some embodiments, the photoresist composition is any one of the following photoresist compositions prepared from the following raw materials in parts by weight:
the monomer B is
the monomer C
is the monomer D is
The present disclosure provides a preparation method for the photoresist composition as described above, the preparation method comprising the following steps: mixing the components of the photoresist composition as described above uniformly.
In the preparation method for the photoresist composition, after the mixing, it may further comprise a filtration step. The method of the filtration can be conventional in the art, preferably to use a filter for filtering. The pore size of the filter membrane of the filter is preferably 0.2 μm.
The present disclosure provides a use of the photoresist composition in ArF dry lithography.
The ArF dry lithography preferably comprises the following steps:
In S1, the substrate can be a substrate for the manufacture of integrated circuits (such as one or more of Si, SiO2, SIN, SION, TIN, WSi, BPSG, SOG, and organic anti-reflective film), or a substrate for the manufacture of mask circuits (such as one or more of Cr, CrO, CrON, MoSi2, and SiO2).
In S1, the method of coating can be a conventional one used in the art for forming a photolithographic pattern, such as spin coating.
In S1, the baking temperature can be a conventional one used in the art for forming a photolithographic pattern, such as 60 to 200° C.
In S1, the baking time can be a conventional one used in the art for forming a photolithographic pattern, such as 1 to 10 minutes, or such as 1 minute.
In S1, the thickness of the photoresist layer can be 0.05 to 2 μm, such as 100 nm.
In S2, the exposure can be carried out using conventional operations used in the art for forming photolithographic patterns, such as high-energy radiation (e.g., KrF excimer laser, ArF excimer laser (e.g., exposure in an ArF excimer laser stepper (Nikon Corp., NA-0.68), or EUV), wherein the dose of exposure can be 1 to 200 mJ/cm2 (such as 10 to 100 mJ/cm2), or using electron beam exposure, wherein the dose of exposure can be 0.1 to 100 C/cm2 (such as 0.5 to 50 μC/cm2); or, for example, by completing the exposure through an immersion lithography method that involves providing a liquid with a refractive index of at least 1.0 (such as water) between the projection lens and the photoresist layer.
In S3, the baking temperature can be those conventional used in the art for forming photolithographic patterns, such as 60 to 150° C., or such as 90 to 100° C., or such as 95° C.
In S3, the baking duration can be a conventional baking duration used in the art for forming photolithographic patterns, such as 1 to 5 minutes, or such as 1 minute.
In S4, the method of development can be a conventional method of development used in the art for forming photolithographic patterns, preferably one or more than one of immersion, spin-coating immersion, and spraying, such as spin-coating immersion.
In S4, the developer used for the development can be a conventional developer used in the art for forming photolithographic patterns, such as an alkaline aqueous solution and/or an organic solvent.
The concentration of the alkaline aqueous solution may range from 0.1 to 5 wt %, preferably 2 to 3 wt % tetramethylammonium hydroxide (TMAH) solution.
The organic solvent can be one or more than one of 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methyl cyclohexanone, acetophenone, methyl acetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, isopentyl acetate, butenyl acetate, benzyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl crotonate, methyl ricinoleate, ethyl ricinoleate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, benzyl acetate, methyl phenylacetate, benzyl formate, ethyl phenylformate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and ethyl 2-phenylacetate.
In S4, the development temperature can be those conventional used in the art for forming photolithographic patterns, preferably 10 to 30° C., such as room temperature.
In S4, the development duration can be a conventional development duration used in the art for forming photolithographic patterns, such as 0.1 to 3 minutes, such as 0.5 to 2 minutes.
Any desired steps can be added to the pattern formation method. For example, following the formation of the photoresist layer, a step involving rinsing with pure water (post-soaking) can be introduced to extract photoacid generators or other components from the film surface or to wash away particles. After exposure, a rinsing (post-soaking) step can be introduced to remove any water remaining on the film post-exposure.
On the basis of conforming to common knowledge in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain various preferred embodiments of the present disclosure.
Reagents and raw materials used in the present disclosure are all commercially available.
The positive effects of the present disclosure lie in: the photoresist comprising the resin of the present disclosure has at least the following advantages: excellent photosensitivity, a good depth of focus (DOF), and a good critical dimension uniformity (CDU).
The present disclosure is further described below by way of examples; however, the present disclosure is not limited to the scope of the described examples. For the experimental methods in which no specific conditions are specified in the following examples, selections are made according to conventional methods and conditions or according to the product instructions.
In the following examples, unless a specific operating temperature is defined, it is to be understood that the procedures are conducted at room temperature. Room temperature refers to the range of 10 to 30° C.
Under a nitrogen atmosphere, a solution was prepared by dissolving the following monomer A, monomer B, monomer C, monomer D in 70 g of propylene glycol monomethyl ether acetate (PGMEA) according to the parts by weight (g) in Table 1. Under a nitrogen atmosphere, this solution was then dropwise added to 30 g of propylene glycol monomethyl ether acetate (PGMEA) over 5 hours, with stirring at 70° C. After the dropwise addition is completed, stirring was continued at 70° C. for 3 hours. The reaction solution was cooled to room temperature and added dropwise to 1,000 g of methanol. The precipitated solid was collected by filtration and dried under vacuum at 40° C. for 24 hours to obtain resins 1 to 6 and comparative resins 1 to 6 in the form of powder solids.
The raw materials for the photoresists 1 to 21 of the present disclosure and the comparative photoresists are listed in Table 2
According to the formulations shown in Table 3, the solid components were added to the liquid components and stirred until homogenous. The mixture was filtered through a filter with a pore size of 0.2 μm to prepare the photoresists 1 to 21 and comparative photoresists 1 to 16 in solution form.
ArF dry lithography pattern test (hole pattern test)
On a substrate (silicon wafer), a carbon film ODL-70 (carbon content: 65 wt %, Shin-Etsu Chemical Co., Ltd.) was deposited to a thickness of 200 nm, and on top of it, a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43 weight %; Shin-Etsu Chemical Co., Ltd.) is deposited to a thickness of 35 nm. Then, a photoresist composition was spin-coated on top, followed by baking on a hotplate at 200° C. for 60 seconds to form a 100 nm thick photoresist layer.
Exposure was carried out in an ArF excimer laser stepper (Nikon Corp., NA-0.68). The photoresist layer was baked (PEB) at 95° C. for 60 seconds. After PEB, the developer listed in Table 4 was injected from the developer nozzle while the wafer was spun at 30 rpm for 3 seconds, followed by a static soak development for 27 seconds. A pattern of holes with 100 nm spacing was formed.
The hole pattern formed as described above was observed under a TD-SEM (CG-4000, Hitachi High-Technologies Corp.). The optimal dose (Eop) is the exposure dose (mJ/cm2) that provides a hole diameter of 50 nm at 100 nm spacing and is used as an index for photosensitivity.
The hole size at the optimal dose was measured under TD-SEM (CG-4000), and the DOF margin providing a size of 50 nm±5 nm was determined. A larger value indicates smaller changes in pattern size with changes in DOF, and therefore, a better DOF margin.
The hole pattern formed as described was observed under TD-SEM (CG-4000), and the diameters of 125 holes were measured. The triple value (30) of the standard deviation (c) was calculated and recorded as CDU. A smaller value of 30 indicates a smaller deviation of the hole.
After PEB (with no delay, PPD-Oh), the wafer was immediately developed by suspension immersion for 30 seconds to form a hole pattern with a diameter of 50 nm and a spacing of 100 nm. In another operation, the wafer was kept for 6 hours (PPD=6 hours) after PEB, and then it was similarly developed to form a pattern.
The hole patterns at PPD-Oh and 6 h were observed under TD-SEM (CG-4000), and the diameters of 125 holes were measured. The average value was taken as the hole size (CD), and CDU was calculated using the same method as above. The difference between the CD at PPD Oh and the CD at PPD 6 h was taken as the CD shrinkage caused by PPD (APPD CD).
The effects of the photoresists PI to P21 prepared in Examples 7 to 28 and the photoresists CP1 to CP16 prepared in Comparative Examples 7 to 23 are shown in Table 4.
The developers used in Table 4 are butyl acetate (D-1), 2-heptanone (D-2), and methyl benzoate (D-3).
As can be seen from the table above, the photoresist compositions within the scope of the present disclosure, compared with the comparative photoresist compositions, show improvements in DOF and CDU, and a reduction in CD shrinkage caused by PPD (i.e., smaller CD changes). Especially, the photoresist containing resin 1 of the present disclosure, compared with photoresists formed by resins 2-6, exhibits a significantly reduced critical dimension (CD) shrinkage.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202111245391.X | Oct 2021 | CN | national |
The application is a Continuation-in-part application of International Application No. PCT/CN2021/134376, filed on Nov. 30, 2021, which claims the priority of Chinese patent application No. 202111245391X filed on Oct. 26, 2021, the contents of which are incorporated herein by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2021/134376 | Nov 2021 | WO |
| Child | 18637481 | US |
