Deuteroxyl-doped silica glass, optical member and lithographic system comprising same and method of making same

Abstract

What is disclosed includes OD-doped synthetic silica glass capable of being used in optical elements for use in lithography below about 300 nm. OD-doped synthetic silica glass was found to have significantly lower polarization-induced birefringence value than non-OD-doped silica glass with comparable concentration of OH. Also disclosed are processes for making OD-doped synthetic silica glasses, optical member comprising such glasses, and lithographic systems comprising such optical member. The glass is particularly suitable for immersion lithographic systems due to the exceptionally low polarization-induced birefringence values at about 193 nm.

1 - 44 . (canceled) 
   
   
       45 . A process for making OD-doped synthetic silica glass material capable of being used in the light path of the lithographic irradiation of a lithographic device operating at a wavelength below about 300 nm, comprising the following steps:
 (I) providing a plurality of particles comprising silica;   (II) depositing the a plurality of particles on a supportive deposition surface at an elevated temperature such that the particles are consolidated into transparent glass material in situ,   wherein:   either in step (I), the a plurality of particles provided are D-containing and/or in step (II), the deposition and consolidation are carried out in a D-containing atmosphere,   such that the obtained silica glass comprises OD and optionally OH, and the ratio of n(OD)/(n(OD)+n(OH)) is higher than about 2×10 −4 .   
   
   
       46 . A process according to  claim 45 , wherein the obtained silica glass comprise sodium less than about 50 ppb by weight. 
   
   
       47 . A process according to  claim 45 , wherein in step (I), the particles are generated by flame hydrolysis of at least one Si-containing precursor compound. 
   
   
       48 . A process according to  claim 47 , wherein in step (I), the Si-containing precursor compound is selected from organosilicon compounds and silicon halides. 
   
   
       49 . A process according to  claim 45 , wherein in step (II), the deposition is initiated on an essentially planar top surface of a horizontally rotating table. 
   
   
       50 . A process according to  claim 45 , wherein in step (II), the deposition and consolidation are carried out in the presence of D 2 O. 
   
   
       51 . A process according to  claim 45 , wherein in step (II), the deposition and consolidation are carried out in the presence of H 2 O. 
   
   
       52 . A process according to  claim 51 , wherein the Si-containing precursor compound comprises D. 
   
   
       53 . A process according to  claim 47 , wherein the flame is generated by at least one reaction involving a D-containing compound. 
   
   
       54 . A process according to  claim 45 , wherein in step (I), the particles are provided via a soot dispenser. 
   
   
       55 . A process according to  claim 45 , wherein in step (I), the particles are provided via a plasma-assisted process. 
   
   
       56 . A process according to  claim 45 , further comprising the following step:
 (III) treating the consolidated glass obtained in step (II) in an atmosphere comprising H 2  and/or HD and/or D2.   
   
   
       57 . A process according to  claim 56 , wherein in step (III), the treatment temperature is lower than about 600° C. 
   
   
       58 . A process according to  claim 56 , wherein in step (III), the treatment temperature is higher than about 600° C. 
   
   
       59 . A process according to  claim 56 , wherein in step (III), the ratio of (2n(H 2 )+n(HD)))/2(n(H 2 )+n(D 2 )+n(HD)) is higher than or equal to the natural abundance of H. 
   
   
       60 . A process according to  claim 56 , wherein in step (III), the ratio of (2n(D 2 )+n(HD))/2(n(H 2 )+n(D 2 )+n(HD)) is higher than or equal to the natural abundance of D. 
   
   
       61 . A process according to  claim 56 , wherein in step (III), the treatment time and temperature is chosen such that the sum total of the concentration of H 2 , HD and D 2  in the treated glass is between about 0.1×10 16  to about 5×10 19  molecules/cm 3 . 
   
   
       62 . A process according to  claim 56 , wherein in step (I), particles comprising dopants are provided and mixed with the particles comprising silica. 
   
   
       63 . A process according to  claim 62 , wherein the particles comprising dopants comprise at least one of Cl, TiO 2 , F and Al 2 O 3 . 
   
   
       64 . A process according to  claim 63 , wherein the particles comprising dopants comprise fluorine. 
   
   
       65 . A process for making OD-doped synthetic silica glass material capable of being used in the light path of the lithographic irradiation of a lithographic device operating at a wavelength below about 300 nm, comprising the following steps:
 (A) providing a particle preform comprising a plurality of particles comprising silica;   (B) optionally purifying and/or drying the particle preform;   (C) optionally further doping the particle preform with dopants;   (D) consolidating the particle preform at an elevated temperature to dense glass; and   (E) optionally treating the consolidated glass obtained in step (D) in the presence of H 2 , HD and/or D 2 ,   wherein in at least one of steps (A), (B), (C), (D) and (E), OD is introduced into or formed in the glass such that obtained silica glass comprises OD and optionally OH, and the ratio of n(OD)/(n(OD)+n(OH)) is higher than about 2×10 −4 .   
   
   
       66 . A process according to  claim 65 , wherein the obtained silica glass comprises less than about 50 ppb by weight of sodium. 
   
   
       67 . A process according to  claim 66 , wherein the soot preform provided in step (A) comprises sodium lower than about 50 ppb by weight. 
   
   
       68 . A process according to  claim 65 , wherein:
 the soot preform provided in step (A) comprises sodium higher than about 50 ppb by weight;   step (B) is carried out subsequent to step (A); and   upon completion of step (B), the soot preform comprises sodium less than about 50 ppb by weight.   
   
   
       69 . A process according to  claim 65 , wherein in at least one of steps (A), (B), (C) and (D), OD is introduced into or formed in the glass. 
   
   
       70 . A process according to  claim 65 , wherein step (A) comprises the following steps:
 (A1) providing a plurality of particles; and   (A2) depositing the particles on a rotating supporting surface to form the particle preform.   
   
   
       71 . A process according to  claim 70 , wherein in step (A1), the particles are provided by (A1.1) flame hydrolysis of at least one silicon-containing precursor compound, which may be plasma-assisted; or (A1.2) a soot dispenser, which may be plasma assisted; or (A1.3) other plasma-assisted process. 
   
   
       72 . A process according to  claim 71 , wherein in step (A1), the particles are provided by (A1.1), and the particles are essentially not OD-doped. 
   
   
       73 . A process according to  claim 71 , wherein in step (A1), the particles are provided by (A1.1), and the particles provided are OD-doped. 
   
   
       74 . A process according to  claim 73 , wherein in step (A1), the particles are provided by flame hydrolysis in the presence of a D-containing compound. 
   
   
       75 . A process according to  claim 74 , wherein in step (A1), the particles are provided by flame hydrolysis in the presence of D 2 O. 
   
   
       76 . A process according to  claim 70 , wherein in step (A2), the deposition involves a process selected from (A2.1) outside vapor deposition; (A2.2) inside vapor deposition; (A2.3) vapor axial deposition; and (A2.4) planar deposition. 
   
   
       77 . A process according to  claim 65 , wherein step (A) comprises the following steps:
 (A(i)) forming a sol-gel comprising silica; and   (A(ii)) forming the particle preform from the sol-gel.   
   
   
       78 . A process according to  claim 77 , wherein step (A(i)) is carried out in the presence of or from a D-containing compound. 
   
   
       79 . A process according to  claim 78 , wherein step (A(i)) is carried out in the presence of D 2 O. 
   
   
       80 . A process according to  claim 65 , wherein step (B) is carried out and such step is carried out in an atmosphere comprising at least one purifying/drying agent selected from F 2 , Cl 2 , Br 2 , a halogen-containing compound, CO, CO 2 , and compatible mixtures thereof. 
   
   
       81 . A process according to  claim 80 , wherein the halogen-containing compound is selected from HX, COX 2 , SOX 2 , CX 4  and SX 6 , wherein X is selected from F, Cl, Br and combinations thereof. 
   
   
       82 . A process according to  claim 80 , wherein step (B) is carried out in an atmosphere comprising Cl 2 , Br 2  or mixtures thereof, with or without containing CO. 
   
   
       83 . A process according to  claim 80 , wherein immediately after step (B), the particle preform has an [OH]+[OD] less than about 50 ppm by weight of the total composition. 
   
   
       84 . A process according to  claim 65 , wherein step (C) is carried out, and such step is carried out in the presence of an atmosphere comprising dopant(s). 
   
   
       85 . A process according to  claim 84 , wherein step (C) is carried out in the presence of a D-containing compound. 
   
   
       86 . A process according to  claim 84 , wherein step (C) is carried out in the presence of D 2 O, D 2  or both. 
   
   
       87 . A process according to  claim 85 , wherein in step (C) exchange of OD for OH is carried out. 
   
   
       88 . A process according to  claim 87 , wherein immediately after step (C), the ratio of n(OD)/(n(OD)+n(OH)) in the particle preform is higher than about 0.02. 
   
   
       89 . A process according to  claim 65 , if step (B) or step (C) is carried out, at least one of these two steps is carried out in the presence of a reductive atmosphere. 
   
   
       90 . A process according to  claim 89 , wherein in the reductive atmosphere in which step (B) or step (C) is carried out comprises a gas selected from H 2 , D 2 , HD, hydrocarbons, D-containing hydrocarbons, and the like. 
   
   
       91 . A process according to  claim 89 , wherein after step (B) or step (C), if carried out, and whichever is later, an oxidation step (C(A)) is carried out wherein the particle preform is subjected to an oxidative atmosphere in which oxygen-deficient sites in the particle preform can be healed. 
   
   
       92 . A process according to  claim 91 , wherein step (C(A)) is at least part of step (D). 
   
   
       93 . A process according to  claim 91 , wherein the oxidative atmosphere in step (C(A)) comprises H 2 O, D 2 O, O 2  and/or O 3 . 
   
   
       94 . A process according to  claim 65 , wherein steps (B) and (C) are carried out at least partially simultaneously. 
   
   
       95 . A process according to  claim 65 , wherein steps (C) and (D) are carried out at least partially simultaneously. 
   
   
       96 . A process according to  claim 65 , wherein step (D) is carried out in an atmosphere comprising He. 
   
   
       97 . A process according to  claim 65 , wherein step (U) is carried out in an atmosphere comprising O 2 . 
   
   
       98 . A process according to  claim 65 , wherein step (D) is carried out in the presence of H 2 O. 
   
   
       99 . A process according to  claim 65 , wherein step (D) is carried out in the presence of D 2 O. 
   
   
       100 . A process according to  claim 99 , wherein step (D) is carried out in an atmosphere essentially free of H 2 O and HDO. 
   
   
       101 . A process according to  claim 65 , wherein step (D) is carried out in the presence of D 2 , HD or both. 
   
   
       102 . A process according to  claim 65 , wherein step (E) is carried out, and such step (E) is carried out in the presence of H 2 . 
   
   
       103 . A process according to  claim 102 , wherein step (E) is carried out in an atmosphere essentially devoid of D 2  and HD. 
   
   
       104 . A process according to  claim 103 , wherein step (E) is carried out at a temperature lower than about 600° C. 
   
   
       105 . A process according to  claim 101 , wherein step (E) is carried out at a temperature below about 1000° C. 
   
   
       106 . A process according to  claim 65 , wherein step (E) is carried out, and such step (F) is carried out in the presence of D 2  and/or HD. 
   
   
       107 . A process according to  claim 106 , wherein step (E) is carried out in an atmosphere essentially devoid of H 2 . 
   
   
       108 . A process according to  claim 107 , wherein step (E) is carried out in an atmosphere essentially devoid of HD and H 2 . 
   
   
       109 . A process according to  claim 106 , wherein step (E) is carried out at a temperature higher than about 600° C. 
   
   
       110 . A process according to  claim 65 , wherein:
 the dense glass resulting from step (D) comprises OH;   step (F) is carried out; and   in step (E), the glass is treated in an atmosphere comprising D 2 , HD and/or H 2  to effect H/D exchange in the dense glass to obtain the desired [OH] and [OD] in the glass.   
   
   
       111 . A process according to  claim 110 , wherein:
 the dense glass resulting from step (D) is essentially not OD-doped; and   in step (E), the glass is treated in an atmosphere comprising D 2  to effect H/D exchange in the dense glass to obtain the desired [OH] and [OD] in the glass.   
   
   
       112 . A process according to  claim 111 , wherein:
 in step (E), the glass is treated in an atmosphere comprising D 2  to effect H/D exchange such that at the end of the step (E), the glass has a ratio of n(OD)/(n(OD)+n(OH)) of at least 0.5.   
   
   
       113 . A process according to  claim 112 , wherein:
 at the end of step (E), the glass has a ratio of n(OD)/(n(OD)+n(OH)) of at least 0.9.   
   
   
       114 . A process according to  claim 110 , wherein step (E) is carried out at a temperature of at least 600° C. 
   
   
       115 . A process according to  claim 114 , wherein step (E) is carried out at a temperature of at least 800° C. 
   
   
       116 . A process for making OD-doped synthetic silica glass capable of being used in the light path of the lithographic irradiation of a lithographic device operating at a wavelength below about 300 nm, comprising the following steps:
 (a) providing a plurality of OD-doped particles comprising silica; and   (b) melting the particles at an elevated temperature to obtain a transparent glass.   
   
   
       117 . A process according to  claim 116 , wherein step (a) comprise the following steps:
 (a1) generating a plurality of particles comprising silica;   (a2) optionally purifying and/or drying the particles;   (a3) optionally doping the particles in an atmosphere comprising at least one D-containing compound, and   (a4) optionally treating the particles in an oxidative atmosphere to at least partly heal oxygen-deficient sites in the particles.   
   
   
       118 . A process according to  claim 117 , wherein in step (a3), the at least one D-containing compound comprises D 2 O. 
   
   
       119 . A process according to  claim 116 , wherein step (a) involves flame hydrolysis of a Si-containing precursor compound. 
   
   
       120 . A process according to  claim 116 , wherein step (a) involves a sol-gel process of a Si-containing compound. 
   
   
       121 . A process according to  claim 116 , wherein in step (b), the melted glass is also homogenized. 
   
   
       122 . A process according to  claim 116 , further comprising the following step (c) after step (b):
 (c) treating the glass in an atmosphere comprising H 2 , D 2  and/or HD.   
   
   
       123 - 124 . (canceled) 
   
   
       125 . A process for making OD-doped synthetic silica glass capable of being used in the light path of the lithographic irradiation of a lithographic device operating at a wavelength below about 300 nm, comprising the following steps:
 (a) providing at least one consolidated OD-doped silica glass;   (b) melting the OD-doped silica glass and homogenizing it at an elevated temperature to obtain a glass having an essentially uniformly distributed [OD] and/or [OH] therein.   
   
   
       126 . A process according to  claim 125 , wherein:
 in step (a), at least two OD-doped silica glasses having differing [OD] are provided; and   in step (b), the at least two silica glasses are mixed and homogenized.   
   
   
       127 . A process for making OD-doped synthetic silica glass capable of being used in the light path of the lithographic irradiation of a lithographic device operating at a wavelength below about 300 nm, comprising the following steps:
 (a) providing a consolidated silica glass comprising OH;   (b) treating the consolidated glass in an atmosphere comprising D 2 , H 2 , and/or HD to effect H/D exchange to the desired [OH] and [OD] in the glass.   
   
   
       128 . A process according to  claim 127 , wherein:
 the dense glass provided in step (a) is essentially not OD-doped; and   in step (b), the glass is treated in an atmosphere comprising D 2  to effect H/D exchange in the dense glass to obtain the desired [OH] and [OD] in the glass.   
   
   
       129 . A process according to  claim 128 , wherein:
 in step (b), the glass is treated in an atmosphere comprising D 2  to effect H/D exchange such that at the end of the step (b), the glass has a ratio of n(OD)/(n(OD)+n(OH)) of at least 0.5.   
   
   
       130 . A process according to  claim 129 , wherein:
 at the end of step (b), the glass has a ratio of n(OD)/(n(OD)+n(OH)) of at least 0.9.   
   
   
       131 . A process according to  claim 127 , wherein step (b) is carried out at a temperature of at least 600° C. 
   
   
       132 . A process according to  claim 131 , wherein step (b) is carried out at a temperature of at least 800° C.