TW200416491A - Overcoating composition for photoresist and method for forming photoresist pattern using the same - Google Patents

Abstract

Overcoating compositions for photoresist and methods for reducing linewidth of the photoresist patterns are disclosed. More specifically, an overcoating composition containing acids is coated on a whole surface of a photoresist pattern formed by a common lithography process to diffuse the acids into the photoresist pattern. The photoresist in the portion where the acids are diffused is developed with an alkali solution to be removed. As a result, the linewidth of positive photoresist patterns can be reduced, and the linewidth of negative photoresist patterns can be prevented from slimming in a subsequent linewidth measurement process using SEM.

Description

200416491 (1) Description of the invention: [Technical field to which the invention belongs] $ I 明 解 A photoresist coating composition and a method for reducing the line width of the photoresist pattern. f + +, ^ f 5 is formed by a general lithographic etching process, and the entire surface of the resist pattern is coated with an acid-containing outer coating composition to spread the acid into the photoresist pattern. The portion of the photoresist in which the acid is diffused is removed by the experimental ridge solution '. As a result, the line width of the positive photoresist pattern can be reduced, and the line width of the negative photoresist pattern can be avoided to be finer in the subsequent line width measurement method using sem. [Previous technology] The transmission energy has been increased to increase the exposure energy to reduce the line width of the photoresist pattern. Although the above method is extremely effective in reducing the line width of the photoresist pattern, the amount of light diffracted becomes too large according to the increase in energy, as shown in FIG. As a result, a part of the photoresist pattern (0) was removed, and the photoresist pattern was changed into a triangle shape. In addition, the thickness of the photoresist pattern 20 is reduced. The triangle profile and the reduction of the thickness of the resist degrade the subsequent etching process. In particular, when the pattern line width is measured, the triangle pattern deteriorates the reproducibility, and turns into a base film to make the subsequent etching pattern into a triangle. . As a result, the impedance is increased. The reduction in the thickness of the M-blocker cannot provide a masking function to the plasma in the process of etching the base film. As a result, the etching pattern is transformed and cracked.

When a negative photoresist pattern is formed, SEM measurement is performed by setting a target of a critical dimension (hereinafter referred to as 0 '). This sem measurement is immediately followed by [ο several = the same as the 5 Hai standard. However, within 10 minutes after SEM measurement, the pattern CD 89641 200416491 decreased due to the high-energy electron beam generated in the photoresist composition during the measurement process. The pattern CD is further reduced due to the far-ultraviolet light sources such as Ar * F (193 nm) and VUV (157 nm) in the manufacture of ultra-fine high-concentration semiconductors. It satisfies various physical properties such as low light absorption, high etching, excellent substrate adhesion, transparency to light sources, and developing ability in alkaline developers. The CD is reduced.

[Summary of the Invention] Most photoresist compositions at nm and 157 nm do not contain aromatic materials, which can slow down the high-energy electron beams generated during the SEM measurement process. As a result, the exposure time

[Embodiment] An outer coating composition. The photoresist pattern of the outer coating composition is shown, including water-soluble polymer, brown photoresist outer coating composition, acidic compound and water.

Compound or polyethylenyl P ratio σ 89641 200416491 Formula 1

Wherein 11 'is fluorene or CH3; R5 and R6 are independently fluorene or Ci-C3 alkyl; and η is the number of repeating units. The η is an integer of 50 to 150 and the molecular weight of the compound of Formula 1 ranges from 5000 to 15,000. The compound of Formula 1 is preferably poly (N, N-dimethylacrylamide). The acidic compound may be an organic sulfonic acid such as p-ammonium sulfonic acid monohydrate. The acidic compound is present in a range of 2 to 20% by weight, and preferably in a range of 5 to 10% by weight, based on the amount of water-soluble polymer. Distilled water can be used as the composition's soluble polymer in an amount of 5,000 to 2,000 weight. /. Range. Solvent water. The amount of water present is in the range of 4,000% by weight of the water present, preferably from 500 to a method of forming a photoresist pattern, including ... forming a photoresist pattern by a lithographic etching process; said overcoat composition and (b) forming an overcoat layer on the entire surface of the photoresist pattern; (C) baking the overcoat layer; and using an alkaline developing solution to develop the overcoat layer 89641 200416491 where lithographic etching is used Step (a) of forming a photoresist in the manufacturing process includes (a-1) coating a semiconductor substrate with a chemically-enhanced <pre-resistor composition and baking the substrate to form a photoresist film. (A-2) exposing the photoresist film; (a-3) baking the photoresist film; and (a-4) developing the photoresist film. Preferably, the photoresist pattern obtained in step (a) has a coating height ranging from 2000 to 3000 angstroms in step (a-1), and a coating thickness ranging from 200 to 5000 in step (b). Angstroms are calculated from the upper surface of the photoresist M 糸 in step (a). The baking process in step (C) is an acid diffusion baking process. And Ji Jiu performed in the range of 50 to 150 C for> 30 to 90 seconds. The baking process is performed to diffuse the acid escaping from the outer coating into the photoresist pattern. As a result, the area of the photoresist pattern with acid is increased and the beans can be removed by the alkaline developing solution. Here, because the temperature of the acid diffusion baking process becomes higher: the thickness of the overcoat layer becomes thicker ', the acid diffusion distance becomes longer. Accordingly, the pattern width can be adjusted using the above theory. The experimental developing solution in step (2) may be TMAH, KOH or NaOH solution. Traditionally, the overcoat composition is coated on a photoresist film before forming a photoresist pattern, followed by a subsequent photolithographic etching process. However, after the photoresist pattern is formed by a general lithographic etching process, the disclosed outer coating composition is coated on the entire surface of the photoresist pattern. Then, this baking process is performed to obtain a fine pattern. That is, the disclosed composition is formed on the entire surface of the photoresist pattern, and then the baking process is performed to diffuse the acid into the photoresist pattern. From 89641 200416491, the photocut pattern area that has diffused into the acid can reduce the line width of the pattern. g w sex developing solution is removed. Form &amp; on the negative pattern. The resulting structure is then baked: the acid in the outer coating compound is absorbed into the upper case and the result is included in the composition process to measure the line width as the dish changes. SEM production is used to prevent the pattern from becoming finer. In this way, the composition on the photoresist pattern of the outer coating disclosed by 'is used. The horse is externally coated on a spleen formed in accordance with a preferred specific example in advance for illustration. The tea recipe will be described in more detail with reference to the drawings. Referring to FIG. 2a, a photoresist film is exposed on the chemically amplified substrate (not shown) in the step (a-1) in the range of 3000 angstroms. The photoresist composition (not shown) is coated on a semiconductor and baked to form a photoresist film (not shown). Fire, bake and develop to form a photoresist pattern 100. The height of the photoresist pattern 100 is preferably from 2000 to 2000, and the photoresist of Ho-like chemical A can be used in the photoresist composition. :: Comparative photoresist composition includes a photopolymer having a repeating unit of Formula 2:

Where X ΛΤ, 1 2, Υι, γ2, z 丨 and z2 are independently 0: ^ 12 or (: ϋ2ί: Η2; 89641 200416491

R1, R3, and R4 are independently selected from the group consisting of fluorene, substituted Ci-Cio alkyl groups, and unsubstituted C 1 -C 1 0 alkyl groups; R2 is K1 () via alkyl; R * is an acid Unstable protecting groups; P, q and r are independently integers of 0 to 2; and the relative proportion of a · b · C · d is 5 to 90 mole%: 5 to 90 mole%: 0 to 90 Molar%: A range of 0 to 90 Molar%. The solution of the alkaline developer bath of the PR material can be determined by the acid labile protective group which can be removed by the acid. That is, the acid-labile protecting group prevents the compound from dissolving in the alkaline developer solution. If the acid-labile protective group is detached by the acid generated by exposure, the PR material is soluble in the developer solution. The protection bases of some Shoubuyiyi's sons and daughters are disclosed in US Patent Nos. 2,122,043 (May 18, 1993), WO 97/3 3 198 (September 12, 1997), WO 96/37526 (November 28, 1996), EP 0 794 458 (September 10, 1997) EP 0 789 2 78 (August 13, 1997), US Patent No. 5,75,68 ( May 12, 1998), US Patent No. M51,678 (April 18, 2000), GB 2,345,286 A (July 5, 20), US Patent No. 6,132,926 (October 17, 2000) US Patent No. 6,143,463 (on January 7, 2000) US Patent No. 6,150,069 (2000 US Patent No. 6,180,316 B January 3G) US Patent No. 6 Knife 5, ㈣w (2001 (May 1, 2010), US Patent No. 6,235,448 m (2001), and US Patent No. 6,235,447 31 (May 22, 2001). Preferably, the tetrahydro leaf I: ran-2-yl group, 2-methyl-2-methyltetrahydrofuran-2-yl acid unstable protecting group is selected from the group consisting of a third butyl group, a tetrahydropyranobiran-2 -Yl, tetrahydrocyclo-2-yl, 89641 -11-200416491, b-methoxypropyl, 1-methoxy-1-fluorenylethyl, 1-ethoxypropyl, I-ethoxy Group consisting of 1-methylethyl, 1-methoxyethyl, 1-ethoxyethyl, first butoxyethyl and 1-isobutylethyl. The photoresist polymer includes a first polymer having a repeating unit having a cyclic-olefin main chain shown in the above formula 2 and a first polymer having a repeating unit of acrylic acid and a main chain. Preferably, the acrylate backbone includes polymethacrylic {4- [2- (4-hydroxybenzyl) -1,1,1,3,3,3-hexafluoropropyl] benzyl | Acrylic acid (i, l, l, 3,3,3,3-hexafluoro-2-third butyl carboxylic acid ester) isopropyl ester}, poly [N-perfluoropropylcisbutene difluorene Amine / Third-Butyl-5-orbornene carboxylate / 2- (Perfluoro-octyl) ethyl methacrylate] or Poly (maleic anhydride / hexafluorobutyl-5-orbornyl Enecarboxylate / 2,6-difluoromethyl benzyl acrylate). The exposure source in step (a-2) is selected from the group consisting of ArF (193 nm), KrF (248 nm), F2 (157 nm), and EUV (13 nm). The exposure energy in step (a_2) ranges from 10 to 30 mJ / cm2. As shown in Fig. 2b, the overcoat composition 102 is coated on the photoresist pattern 100 formed by the method described above.

To 5000 angstroms. Area calculation, 200

Into the upper part of the pattern. The area 104 in the resist pattern. The upper portion of the acid diffusion pattern contained in the composition is hardened (not shown). 89641 200416491 The second roasting process is preferably performed in the temperature range of 50 to i 5Gt for 90 seconds. And: after Tu Guang's baking process increases the areas with acid in the photoresist pattern, the acidic area 104 is removed by the experimental development solution to reduce its line width. ▲ The photoresist shown in Figure 2d or the surface has been hardened Agent pattern 1. The car development solution can be top button, kappa or aqueous solution. Since the pattern line width becomes smaller in proportion to the alkali treatment time, the required line width can be obtained by adjusting the treatment time by mistake. If the concentration of the alkaline developing solution becomes higher, the removal rate of the resist material becomes faster. As a result, radon improves throughput. The region having an acid herein is preferably treated with a 3.8% by weight tmah aqueous solution to 60 seconds. The disclosed outer coating composition will be described in more detail with reference to the following examples, but it is not intended to limit the scope of the invention. I. Preparation of the outer coating composition 1. Outer coating composition η ″ 丨 Step 1 • Synthesis of poly (N, N-dimethyacrylamide) in tetrahydrofuran / combination (300 g) N, N-Dimethylacrylamide (100 g) and AIBN (5 g) were added. The resulting mixture was reacted at 66 for 9 hours. Subsequently, the resulting mixture was precipitated in diethyl ether and dehydrated to obtain pure poly (n, n-dimethylacrylamide) (molecular weight about 12,700, yield about 88%) &lt; 3 NMR of the compound synthesized The spectrum is shown in Figure 3. Step 2. Preferred Specific Example 1 To distilled water (300 g), the poly (N, N_: fluorenylacrylamide) polymer (30 g) obtained in the preparation example and p-methylbenzylsulfonic acid (30 g) were added. 〇5 gp Then, the resulting mixture was filtered with 0.2 micron filter paper, thereby obtaining the disclosed outer coating composition 89641 200416491. The layer composition was added with polyvinylpyrrolidone (molecular weight 1) in Luo water (30 g). 〇〇〇〇〇) (30 g) (Aldnch) and p-toluenesulfonic acid (05 g). Then, the resulting mixture was filtered through 0.02 micron paper to obtain the disclosed outer coating composition Example of forming a positive photoresist pattern 3. Applying an ArF anti-reflective coating (hereinafter referred to as BARC) 溥 film (DHRC-A20) (Donggjin SemiChem Co., Ltd.) with a thickness of 33 angstroms on a wafer Co., Ltd.) A positive ArF photoresist (0-8-H150) (Dongjin SemiChem Co., Ltd.) with a thickness of 2400 angstroms was coated thereon. The resulting structure was exposed and developed using an ArF exposure machine (ASML Co., Ltd.). Therefore, the positive photoresist pattern (line width of about U2 nm) in Figure 4a is obtained. Example 1 Step 2 The outer coating composition was coated on the pattern in FIG. 4a to a thickness of 3000 angstroms. The obtained structure was baked at 15 ° C for 30 seconds. After the baking process, the obtained structure was developed with a 2.38 wt% TMAH solution. Therefore, the pattern of FIG. 4b is obtained (the line width is about 86 nm). The pattern line width display of FIG. 4b is 26 nm smaller than the pattern line width of FIG. 4a. According to this, the resolution of the pattern can be increased by the disclosed method Example 4. An ArF BARC film (DHRC-A20) with a thickness of 330 angstroms was coated on a wafer. A positive ArF photoresist (DHA-H150) with a thickness of 2400 angstroms was coated thereon. The resulting structure was exposed using ArF The machine was exposed and developed to obtain the positive photoresist pattern (line width of about 111 nanometers) as shown in Figure 5a. 89641 14 200416491 The outer coating composition obtained in Example 2 was coated with 3,000 angstroms on the pattern shown in Figure 5a. The obtained structure is baked at 150 ° C for 30 seconds. After the baking process, the obtained structure is developed with a 2.38% by weight TMAH solution, thereby obtaining the pattern of FIG. 5b (see about 88 nm for the line). The pattern line width display of 5b is 23 nanometers smaller than the pattern line width of Fig. 5 &amp; according to this, the pattern can be increased by the disclosed method Analytical force. 5. Apply a photoresist (Axl02p) (Clariant Co., Ltd.) on the wafer. The obtained structure is baked at 120 ° C for 90 seconds to form a photoresist film. The photoresist film Exposure was performed using an ArF exposure machine, and baking was performed at 12 ° C for 90 seconds. The obtained structure was developed with a 2.38 wt.% TMAH aqueous solution, thereby obtaining a positive photoresist pattern (line width of about 100 nm) in FIG. 6a. The outer coating composition obtained in Example 2 was coated on the pattern of FIG. 6a to a thickness of 2400 Angstroms. The resulting structure is at 120. (: Bake for 90 seconds to diffuse the acid. Then the resulting structure is developed with a 2.38% by weight TMAH solution for 40 seconds, thereby obtaining a pattern with a line width of 80 nm (see Figure 6b). The pattern line width display of Figure 6b is larger than that of Figure 6a The pattern line width is reduced by 20 nanometers. According to this, the resolution of the pattern can be increased by the disclosed method. ΠI. Example of forming a negative photoresist pattern Reflective coating film (Dhrc_A20) (Dongjin SemiChem Co., Ltd.). A negative ArF photoresist (GX02) (Dongjin SemiChem Co., Ltd.) having a thickness of 2400 angstroms was coated thereon. The resulting structure was exposed using ArF Machine (ASML Co., Ltd.) 89641 15 200416491 exposed and developed 'so as to obtain a negative photoresist pattern (line width of about 1 丨 2nm). The outer coating composition obtained in step 2 of Example 1 was on the negative pattern. A thickness of 3,000 angstroms was applied. The obtained structure was baked at 15 crc for 2 minutes. After the baking process, the obtained structure was developed with distilled water, thereby obtaining the pattern of FIG. 7a (the line width was about 103 nm). Type Photoresist Pattern Using SEM Instrument at 800V Acceleration Exposure to the electron beam for 30 seconds at 120K magnification, but the line width of the pattern was measured to decrease. See Figure 7b. No thinning was observed in the pattern of 103 nm. Comparative Example 1. On a wafer An ArF anti-reflection coating film (〇1111 (:-A20) (Dongjin SemiChem Co., Ltd.) with a thickness of 330 angstroms was applied thereon. An ArF photoresist (GX02) was applied thereon. The resulting structure was exposed using an ArF exposure machine (ASML Co., Ltd.) was exposed and developed, thus obtaining the positive photoresist pattern (line width of about 112 nm) in FIG. 8a. Although the above negative photoresist pattern was exposed using an SEM instrument at an acceleration voltage of 800V and a magnification of 120K 30 seconds into the electron beam, but the line width of the pattern was reduced. See Figure 8a. The pattern of 9 nm shows a thinning phenomenon. As mentioned earlier, the line width of the pattern can be easily wetted simply. The development process is reduced, and new equipment is not required, which can reduce costs. In addition, the line width of the transistor of the DRAM or MPU can be reduced, thereby improving the operation speed of the semiconductor speed, and the line width of the head of the DRAM can be reduced. Therefore, the capacity is improved. In the subsequent line width measurement process using SEM, 89641 16 200416491 玎 avoids the phenomenon of line width thinning, so the reproducibility and f reliability of the obtained photoresist pattern are improved. [Schematic explanation] Figure 1 shows the increase of display basis Schematic diagram of the process of changing the photoresist pattern line width and wheel rotation by exposure to energy. Figures 2a to 2d are schematic diagrams illustrating the disclosed method of forming a photoresist pattern. Figure 3 is a poly (N, N-dimethylpropylene) Pyramine) ^ 1 ^] 1 spectrum. 4a and 4b are sem photographs of the photoresist pattern obtained in Example 3. 5a and 5b are read photos of the photoresist pattern obtained in Example 4. 6a and 6b are deleted photos of the photoresist pattern obtained in Example 5. Figures 7a and 7b are SEM photographs of the pattern of the pre-resistor served by f obtained in Example 6. Fig. 8a and Fig. 8b are SEM photographs of the pre-resistor pattern of Comparative Example 1j showing +. [Explanation of the symbols in the figure] 1 〇 Photoresist material removed after development 2 〇 Photoresist pattern left after development 1 〇 Photoresist pattern 1 〇 Outer coating 1 ° 4 Acid diffusion area 1 〇 6 Reduced photoresist pattern 89641

Claims (1)

200416491 Patent application scope: 1 · A photoresist outer coating composition, including: water soluble polymer, acidic compound; and water 0 2. The composition according to item 1 of the patent application scope, wherein the water The soluble polymer is a compound of formula 1 or polyvinylpyrrolidone: Where R 'is Η or CH3; R5 and R6 are independently HSCi-Cs alkyl groups; and η is the number of repeating units. 3. The composition according to item 2 of the patent application, wherein η is an integer from 50 to 150. 4. The composition of claim 2 in which the molecular weight of the compound of formula 1 ranges from 5000 to 15,000. 5. The composition according to item 2 of the scope of patent application, wherein the water-soluble polymer represented by Formula 1 is poly (N, N-dimethylacrylamide). 6. The composition according to item 1 of the patent application range, wherein the acidic compound is 89641 organic continuous acid. 7. The composition according to item 1 of the scope of the patent application, wherein the acidic compound is p-methytonic acid monohydrate. δ · The composition as claimed in the scope of the patent application, wherein the acidic compound exists in the range of 2 to 20 weight ° / ° strictly based on the amount of the water-soluble polymer. 9 · The composition as described in the scope of the patent application, wherein The water is present in an amount ranging from 500 to 4000% by weight based on the amount of water-soluble polymer. 1. A method for forming a photoresist pattern, including: r (a) forming a photoresist pattern by a lithographic etching process; (b) applying the above-mentioned overcoat composition on the entire surface of the photoresist pattern Forming an overcoat layer; (C) baking the overcoat layer; and (d) developing the overcoat layer with an empirically developing solution. u. The method of claim 10, wherein step (i) includes: (i) coating a semiconductor substrate with a chemically increased photoresist composition and baking the substrate to form a photoresist film; (a_2) exposing the photoresist film; (^ 3) baking the photoresist film; and (a_4) developing the photoresist film. 12. The height of the resist pattern obtained in step (a) of item 10 of the patent application range is from 2000 to 3,000 angstroms. 13. According to the method of claim 10 in the scope of patent application, the thickness of the overcoat layer in step (b) is calculated from 200 to 5 0 from the upper surface of the μ main system of the photoresist map in step (a). 0 Angstrom range. 89641 200416491 14. The method according to item 10 of the scope of patent application, wherein the step (magic baking process is performed at a temperature range of 50 to 150 ° C for 30 to 90 seconds. 15. If the scope of item 10 of the patent application is Method, wherein the step (the alkaline developing solution of magic is TMAH, KOH or NaOH aqueous solution. 16. The method according to item 丨 丨 of the patent application range, wherein the chemically increased photoresist composition includes a repeating unit having formula 2 Photoresist Polymer: /, Chinese χΐ, χ2, Y 丨, γ2, Z1 and z2 are independently CH2 or CH2CH2; R1 and Han4 are independently selected from the group consisting of H, substituted Ci-Cio alkyl and unsubstituted C1_C1G alkyl Group; R2 is C "C1G hydroxyalkyl group; Feng Mo's unstable protecting group; P, q and r are independently integers of 0 to 2; and the relative proportion of d is 5 to 90 mole% · 5 to 90 mol%: to 90 mol%: 0 to 90 mol%. 17. The method of Lebei in the scope of patent No. 1 of Shenyan, wherein the photoresist polymer includes -The first polymer of the main interest of olefins and the first polymer of the early polymer and the acrylic polymer main chain re-integration I ^ The complex polymer of the second polymer of the early 70. The method of item 17, wherein the first The weight of a polymer 1 8. As stated in the patent scope of Shenyan Patent No. 89641 ^ 16491, the complex unit is represented by the following formula 2: Among them X 1, X 2, γ 1, γ2, eh! And ζ2 are independently ch2 or ch2ch2; h, n3, and n4 are independently selected from the group consisting of H, substituted alkyl, and unsubstituted C1-C1G alkyl; Han 2 is Ci-C1 () hydroxyalkyl ; Is an acid-labile protecting group; P, q, and r are independently integers of 0 to 2; and the relative proportion of a · b · C · d is 5 to 90 mole%: 5 to 90 mole%: 0 to 90 mole%: in the range of 0 to 90 mole%. 19. The method according to item 17 of the scope of patent application, wherein the repeating unit of the second polymer is polyacrylic acid {4_ [2- (4-hydroxyphenyl) 4,3_hexafluoropropyl] phenylcool / Fluorenylacrylic acid (1, 丨, 丨, 3,3,3-hexafluoro_2-tert-butylcarboxylic acid ester) isopropyl ester}, poly [N-perfluoropropylcisbutene difluorene Amine / Third-Butyl-5-orbornene-2-carboxylic acid ester / 2- (Perfluoro-octyl) ethyl methacrylate] or Poly (maleic anhydride / hexafluorobutyl-5 · Orbornene-2-carboxylic acid ester / 2,6-difluoromethyl benzyl acrylate). 20. The method according to item 11 of the scope of patent application, wherein the exposure source in step (a-2) is selected from the group consisting of ArF (193 nm), KrF (248 nm), F2 (157 nm), and EUV (13 nm). Into groups. 89641 200416491 21. The method according to item 11 of the patent application range, wherein the exposure energy of step (a-2) ranges from 10 to 30 mJ / cm2. 89641