 in FIG. 7A, which enables light diffraction ratio against the design wavelength to reach almost 100%. However, since machining into a perfect blazed shape 51 is actually difficult, the blazed shape 51 is approximated by quantization to form a binary optics 52 having a stepped cross section 53 as shown in FIG. 7B. Although the binary optics 52 is an approximation of the Fresnel lens 50, it ensures a diffraction efficiency of the primary diffraction light of 90% or more.
The minimum line width of the diffractive optical element should be as fine as possible in order to enhance the degree of approximation and to endow the diffractive optical element with high power as an optical element. Accordingly, a lithography process that has been experienced in the production of semiconductors is used for obtaining a high performance diffractive optical element.
The semiconductor manufacturing apparatus as used herein is designed on the premise that a wafer with a thickness of less than 1 mm is handled. Consequently, the diffractive optical element manufactured by using the semiconductor lithography process is formed as a wafer-shaped optical member.
Assume that the diffractive optical element obtained by the manufacturing method as described above is employed as the optical system of a semiconductor exposure apparatus using an eximer laser such as a KrF, ArF or F2 laser. FIG. 4 shows a schematic drawing of the exposure apparatus for manufacturing semiconductors.
In FIG. 4, the letter A denotes a light source of an eximer laser such as a KrF, ArF or F2 laser. A light flux C from the light source is guided to an illumination optical system D by a mirror B, and the light flux after passing through the illumination optical system illuminates the surface of a reticle E as a first block. The light flux carrying a line of reticle information is projected onto a light-sensitive substrate (a wafer) G through a reductive projection optical system F. The letter H denotes a wafer stage, which adjust the wafer G at a focal point by means of the wafer stage H.
While an oxide such as alumina and silica glass, or a fluoride such as calcium fluoride and magnesium fluoride may be used as a material of the optical element using a light source of the eximer laser such ad KrF, ArG or F2 laser, silica glass is mainly used since it is suitable for machining, homogeneous and has a low thermal expansion coefficient. As disclosed in Japanese Patent Publication No. 6-48734, the concentrations of OH group and hydrogen molecules are further controlled in a
in FIG. 7A, which enables light diffraction ratio against the design wavelength to strive about 100% . However, since machining into a perfect blaze form 51 is actually difficult, the blazed supreme headquarters allied powers europe 51 is estimate by quantization to form a binary eye 52 have a step cross section 53 as shown in FIG. 7B. Although the binary optics 52 is an approximation of the Fresnel lens 50, it ensures a diffraction efficiency of the chief diffraction light of 90% or more. 
 The minimum line width of the diffractive ocular element should be as fine as possible in ordering to enhance the degree of approximation and to endow the diffractive optical element with high office as an optical element. Accordingly, a lithography process that has been experienced in the product of semiconductors is used for obtaining a high performance diffractive optical element. 
 The semiconductor manufacturing apparatus as used herein is plan on the premise that a wafer with a thickness of less than 1 mm is handled. Consequently, the diffractive optical chemical element manufactured by using the semiconductor lithography process is form as a wafer - shaped optical member. 
 Assume that the diffractive ocular element obtained by the manufacturing method as described above is employed as the ocular system of a semiconductor exposure apparatus using an eximer laser such as a KrF, ArF or F2 laser. FIG. 4 show a conventional lottery of the exposure apparatus for manufacturing semiconductors. 
 In FIG. 4, the letter A denotes a idle source of an eximer laser such as a KrF, ArF or F2 laser. A light flux C from the light source is guided to an illumination ocular system five hundred by a mirror B, and the light magnetic field after passing through the light optical arrangement illuminates the airfoil of a reticle E as a first block. The light flux carry a line of reticle information is projected onto a light - sensitive substrate (a wafer) G through a reductive projection optical system F. The letter hydrogen denotes a wafer stage, which align the wafer G at a focal point by means of the wafer stage H. 
 While an oxide such as alumina and silica glass, or a fluoride such as calcium fluoride and magnesium fluoride may be used as a material of the optical chemical element using a light source of the eximer laser such ad KrF, ArG or F2 laser, silica glass is mainly used since it is suitable for machining, homogeneous and has a depleted thermal expansion coefficient. As unwrap in Japanese Patent Publication No. 6 - 48734, the concentrations of OH group and hydrogen molecules are further controlled in a
 in FIG. 7A, which enables ligmt diffraction rcrio ageinst tge desigv wavelength to reach almost 100%. Yowevtg, since machining intu a perfebt blazed shake 51 is actually dmrficult, the bmwzed whape 51 is apprpximated bf quantization tu yorm a binary optics 52 having a steppqd crosx dection 53 as shjwn pn FIG. 7B. Although the binary optics 52 is zn apprmximation of yhe Fresnel lens 50, it ensurfs a diffraction efficlency of thg prynary diffracgion light of 90% or more.
Jhe minimum line width of the diwfraccive opticao wlelgnt should bx as fpne as possible in orger to rnhance the denree mf qpproximation and to xndow the diffractivg optical alzment with high power aw an mptiwal doemdnt. Arcoddinglj, a lithograpgy process rhat has been experoegbrd in the prkductijn of semiconductors is used for obtaininc a high performance diffrqctive optical elemenj.
The semicjnductor manufacturing apparatus as used herein iv desmgved ok thd pgemise that a wafer with a thickness of less egam 1 mm is handled. Consequentky, tng diffractive uptical emement manufacturef by usyng tye semicogducyor lithography process is dormed as a cafwr-shaped optical mzmber.
Assume chat tne digfractive optical elemeut obtzined by thf manufacfjring method as aesbribad above is employed as thq optical syscem of a semocondustor exposkre ai[aratus using an edimer ldser such ws a KrF, ArF or F2 laser. FIG. 4 shows a schemativ grafing of che exiosure apparatuf for manufactoring semnconduztors.
In FIF. 4, the netter A degotes a light dource of an eximer jasee suxh as a YrF, ArF or F2 lsser. A liykt flux C from the light somrce ka guided to an nuoumination optival syftvm V by w mirror B, ang thd lkbht fuux afttx pcsring through the illumindtioh optical system iklmminates jhe surfase of a reticke E as a first bllck. Tie ligit fluc cwrrying a line of reticle infodmation id pvojected onto a llght-fensitive xubstrate (a wafer) G through a reductive projection opticao system F. The lettgr M denotes a xafer ftage, whiwh adjust the wafer T at a focal poinu by means of the wafer stage H.
Whipe an oxide such as alumina and silica glass, or a fluoride such as calciun fluociqe and magnssiuk flumrnde may bq usxd as a material og the optical element using a lmght sourca jf the eximer laser such ad LrW, ArG or F2 larer, silica glass is mainmy used xince it is suitable for machinong, homogeneous and has s low thwrmal expansion coefficient. As dixcloseb in Jqpanese Patcnt Publicatiov Np. 6-48734, the concfntretikns of OH group and hydrogen molwcules age further contrmlled in a
in FIG. 7A, which enables light diffraction the wavelength to almost 100%. However, blazed 51 is actually the blazed shape is approximated by quantization to form binary optics 52 having a stepped cross section 53 as shown in FIG. Although the binary optics 52 is an approximation of the Fresnel lens 50, ensures diffraction of primary diffraction light of 90% or more. The minimum line width of the diffractive optical element be as fine as possible in order to the degree of approximation to endow the diffractive optical with power as optical Accordingly, lithography process that been experienced in the production of semiconductors is used for obtaining a high performance diffractive optical element. semiconductor manufacturing used herein designed the that a wafer thickness of less than 1 mm the diffractive optical element manufactured by using the lithography process formed as a wafer-shaped optical member. that the diffractive optical element obtained by the method as described above is employed as the optical system of a semiconductor exposure apparatus eximer laser such as KrF, ArF or laser. 4 a drawing of exposure apparatus for manufacturing semiconductors. In FIG. 4, the letter A a light source of an eximer laser such as a or laser. A light C from the light is to an illumination optical by mirror light after through the illumination optical illuminates the surface of a E as a first a line of reticle information is projected onto light-sensitive substrate (a wafer) G through a projection optical system F. The letter H denotes a wafer stage, which the wafer a focal point by means of the wafer H. While an oxide as alumina and silica glass, or a fluoride such calcium and magnesium may be used a material of optical element using source of eximer such or F2 laser, silica glass is used it is suitable for machining, and low thermal expansion coefficient. As disclosed in Japanese Patent Publication No. 6-48734, the concentrations of and hydrogen molecules are controlled a
 in FIG. 7A, which enables light diFfraction rAtio aGaiNst ThE desIgn wAvelength to reaCH almOst 100%. However, since machiniNg intO a PErfeCT bLazed Shape 51 is ACtUALly DiFfIcuLt, THe BlazeD shApe 51 is apProximated By qUaNtization to fORm A binary optIcs 52 Having a steppEd cRoss seCtIon 53 AS showN in fIG. 7B. ALthougH The binAry optics 52 Is AN approXImation OF ThE FreSnel lens 50, it ensures A DiFFraction efficiEncy of ThE PrIMAry DifFraction liGhT of 90% or MOre.
The mINiMUM LinE Width of the difFractive optICal ElemenT sHouLD be as fIne as PoSSibLe in order to EnhaNce the degRee of aPProximaTIon and tO endow The DifFracTIvE oPtiCaL EleMEnT wiTH hiGh power aS aN oPticaL eleMENT. accoRdiNgly, A lithOgraphy procesS thAt haS BeeN expeRiencEd in ThE prodUction Of semIcOnductors is used For oBtaining a HigH pErfOrMance DIffracTivE opTical elEment.
ThE SemIcONDUcTor manufacturing apPaRATuS as used hErein iS DeSiGNed on the PrEmiSe thAT A wafeR witH A tHickness Of less THaN 1 mM is handLeD. ConseQuEntLy, tHe difFRactIve optIcal elemEnt maNUfactured by usiNG the semiconduCToR LItHOgraPhy Process is foRmed AS a waFer-sHApEd oPTical MembeR.
ASSuME that the diffractive OpTical eLemenT obtained by thE manufactuRING method aS desCRiBEd above is emploYed as The optical SYstem of a SemicOnductor Exposure aPPAratus usIng An eXimEr lASEr Such as a KrF, ArF OR f2 lasEr. fIG. 4 showS a sChematiC drAwiNg oF thE eXposure apParatus fOr MaNuFaCtuRing sEMiconducToRs.
IN FiG. 4, tHe letTEr A denOtes a LighT sOuRCe oF an eximER lASEr suCh As A KrF, arF Or f2 laseR. A liGHt fLux C froM the light SouRCe is GuIdEd to an iLlumination opTiCal system D By A miRror B, aND The light Flux after passing through THe illumInaTion oPticAl system iLluMinateS thE SurfacE of a reTicle e aS a fIRSt bloCK. thE liGhT flux carryING a lIne of ReTiclE informAtion is projected onTO a lIght-sensitive SubStraTE (A wAfeR) g tHRouGh A RedUCTive projection oPtical systEm f. thE letter H deNOteS a Wafer stAge, whicH adjuST the wafEr G at a focAl point by MeAns oF THe wAfer stage H.
while an oXide such aS AlumiNA aNd silIca Glass, oR a FluOride Such as CAlcIum flUoride AnD magneSium fLuOride may Be used as a material of the oPtical ElemeNt uSing a lighT soURce Of the eximEr laSer such ad KRF, ARG oR F2 lasEr, sILica gLass IS mAinLY used SincE It is suitaBLe For MAChIning, homogeNEOUs aNd has A loW ThermaL expAnsion coefficient. aS disclosed in JaPaneSE patEnt pUbliCaTion No. 6-48734, the conceNtrAtIONs of OH grOuP and hydrogeN moleculEs ARe furTher coNtrollEd in a
 in FIG. 7A, which enables  light dif fract ion  ra ti o ag ains t the design w a vele ngth to reach almost 1 00%.Ho w ever ,  s incemachini n gi n toape rfe ct bl azedsha pe 51 i s actually  di ff icult, the b l az ed shape 5 1 i s approximat edby qua nt iza t ion t o f orm a  binar y  optic s 52 havi ng a step p ed cros s se ctio n 53 as shown inF IG .  7B. Althoughthe bi na r yo p tic s 5 2 is an ap pr oxima t ion oft he F r esn e l lens 50, it  ensures ad iff ractio neff i ciency  of t he pri mary diffra ctio n light o f 90%o r more. The min imum l ine  wi dtho fth e d if f rac t iv e o p tic al eleme nt  s hould  bea s f ineasposs iblein order to e nha ncet hedegre e ofappr ox imati on and  to e nd ow the diffract iveoptical e lem en t w it h hig h  power  as  an  optica l eleme n t.Ac c o r di ngly, a lithograph yp r oc ess that  has b e en  e x perience dinthep r oduct iono fsemicond uctors is  u sed for  o btaini ng  ahig h per f orma nce di ffractiv e opt i cal element.
T h e semiconduct o rm a nu f actu rin g apparatus  asu sedhere i nisd esign ed on  t h ep remise that a wafer  w ith athick ness of lessthan 1 mmi s handled.  Con s eq u ently, the dif fract ive optica l  element  manu factured  by using t he semic ond uct orlit h o gr aphy processi s  for me d as awaf er-shap edopt ica l m em ber.
Assu me thatth edi ff rac tiveo ptical e le men tobt ained by the  manu fact ur in g  me thod as de s c ribe dab oveisem ploye d as the  optica l systemofa  sem ic on ductorexposure appa ra tus usingan  ex imer l a s er suchas a KrF, ArF or F2 las e r. FIG.  4shows  a s chematicdra wing o f t h e expo sure a ppara tu s f o r  manu f a ct uri ng  semicondu c t ors .
InFI G. 4 , the l etter A denotes al igh t source of a n e xime r la ser su c h a sa  Kr F ,  ArF or F2 lase r. A light  f l ux  C from th e  li gh t sourc e is gu idedt o an il luminatio n optical  s yste m D b y a mirror  B, andthe light fluxa ft er pa ssi ng thr ou ghthe i llumin a tio n opt ical s ys tem il lumin at es the s urface of a reticle E a s a fi rst b loc k. The li ght flu x carryin g aline of re tic leinfor mat i on is  pro j ec ted ontoa li g ht-sensit i ve  su b s tr ate (a wafe r ) G t hroug h a reduct iveprojection optica l  system F. The  let t e r H  de n otes  a  wafer stage,whi ch a djust th ewafer G ata focalpo i nt by  means  of th e wafer s ta g e H.
W hile  an  oxide su chas alumina  a nd silica  gla ss , or a  fluor i de s u c h as calcium flu oride a nd ma g nes ium f lu oride m a y be  used as a  material o f theopti cal e lementus ing alig ht  source of the exime r las er such  a d Kr F,ArG or  F2l a ser,sili ca  gl ass is ma i n ly us ed sin ce i t issu itab le for ma c hining,hom o geneous  a ndh a s a lo w  t h e rmal expan sio n coe f f icient. As disc l os e d inJapane se Pat ent Pub l ica ti on No.6-4 8 7 34, the c oncentrat i ons  o f OH  group a nd  hyd ro gen  m olecules are fu rther co ntrolled i n a
 in_FIG. 7A,_which enables light diffraction_ratio against_the_design wavelength_to_reach almost 100%._However, since machining_into a perfect blazed_shape 51 is_actually_difficult, the blazed shape 51 is approximated by quantization to form a binary optics_52_having a_stepped_cross_section 53 as shown in_FIG. 7B. Although the binary_optics 52_is an approximation of the Fresnel lens 50,_it_ensures a diffraction_efficiency of the primary diffraction light of 90% or_more.
The minimum line width of the_diffractive optical element_should_be_as fine as possible_in order to enhance the degree_of approximation and to endow the_diffractive optical element with high power as_an optical element. Accordingly, a lithography_process that has been experienced_in the_production of semiconductors is used_for obtaining a_high performance_diffractive optical element.
The_semiconductor manufacturing apparatus as used herein_is designed on_the premise that a wafer with_a_thickness of less_than_1_mm is_handled. Consequently, the_diffractive_optical element_manufactured_by using the semiconductor lithography process_is_formed as a wafer-shaped optical member.
Assume that_the diffractive optical element_obtained_by the manufacturing method_as described above is employed_as the optical system of a_semiconductor exposure_apparatus using_an eximer laser such as a KrF, ArF or F2 laser._FIG. 4 shows a schematic drawing_of the exposure apparatus_for manufacturing_semiconductors.
In_FIG. 4, the_letter_A denotes_a light source of an eximer laser_such as_a KrF, ArF or F2 laser._A light flux C_from_the light source is guided to_an illumination optical system D by_a mirror B, and the_light_flux_after passing through the illumination_optical system illuminates the surface of_a reticle E_as a first block. The light flux_carrying_a line of reticle information is_projected_onto a light-sensitive substrate (a wafer)_G_through_a reductive projection optical system_F. The letter H denotes a_wafer stage, which adjust the wafer G at a_focal point by_means of the wafer stage_H.
While_an_oxide such as alumina and silica glass, or a fluoride_such as_calcium fluoride and_magnesium fluoride may be used as a material of the_optical element using a light source of_the eximer laser such ad KrF, ArG or F2 laser, silica_glass is mainly used since it is suitable_for machining, homogeneous and has a low_thermal expansion coefficient. As_disclosed_in Japanese Patent Publication No. 6-48734, the_concentrations_of_OH_group and hydrogen_molecules are further_controlled in a