 of the wafer by the centrifugal force from the rotation of the spin chuck. The treatment solution has temperature higher than room temperature when it is initially supplied on the wafer, but its temperature changes, i.e., cools, as it contacts the wafer and moves along the surface of the wafer. Furthermore, the larger the diameter of wafer processed, the more and greater the temperature difference will be. This is particularly true for large wafers, such as those as large as 12 inches or more in diameter.
The temperature variation in the treatment solution as the process progresses causes a difference in the reaction rate of the treatment solution on respective portions of the wafer. This results in the deterioration of the uniformity of the treatment process itself, and disrupts the etching uniformity or cleaning uniformity of the wafer. These deteriorated uniformity problems are more serious in an etching process forming the contact hole plugs of a conductive material by a spin-etching method.
The higher integration of semiconductor devices that is increasingly needed requires a more precise etching process and cleaning process. As a result, it becomes necessary to increase the accuracy of spin etching processes. Electric-powered wheelchairs are useful for those individuals unable to propel a manual wheelchair or who may need to use a wheelchair for distances or over terrain which would be fatiguing in a manual wheelchair. Typically, an electric motor is usually powered by rechargeable deep-cycle batteries that drive a chassis for providing front, center, or rear wheel drive, and all-wheel drive. However, many such rechargeable batteries are limited to a one day charge, thereby requiring daily recharging.
Solar panel systems are well known sources of electrical power that convert sunlight into electrical energy. Recently, solar energy powered wheelchairs have been designed that rely solely on solar energy as a source of electrical energy. In these types of wheelchairs, the solar panels are arranged above the wheelchair using a fixed support structure that provides an excellent orientation for receiving sunlight as well as shade to the individual sitting in the wheelchair. However, such support structures, for example canopies, are either fixed structures with no means for adjustment or support structures with no easy and accessible means for making various types of adjustments to the canopy, especially for a user that may be handicapped and have limited mobility for adjusting the overhead canopy. 1. Field of the Invention
The present invention relates to a multi-beam scanning apparatus and an image forming apparatus using the same and, more particularly, to a light scanning optical system suitable for an image forming apparatus such as a
of the wafer by the centrifugal force from the rotation of the spin chuck. The treatment solution take temperature eminent than room temperature when it is initially supplied on the wafer, but its temperature changes, i.e., cools, as it touch the wafer and moves along the surface of the wafer. Furthermore, the bombastic the diameter of wafer action, the more and greater the temperature deviation will be. This is particularly true for big wafers, such as those as big as 12 inch or more in diameter. 
 The temperature variation in the treatment solution as the process progresses causes a deviation in the reaction rate of the treatment solution on respective share of the wafer. This results in the deterioration of the uniformity of the treatment process itself, and disrupts the etch uniformity or cleaning uniformity of the wafer. These deteriorated uniformity problems are more serious in an etching process form the contact hole plugs of a conductive material by a spin - etching method. 
 The higher integration of semiconductor devices that is increasingly needed requires a more precise etching process and cleaning process. As a consequence, it becomes necessary to increase the accuracy of spin engrave summons. Electric - powered wheelchairs are useful for those individuals unable to propel a manual wheelchair or who may need to practice a wheelchair for distances or over terrain which would be fatiguing in a manual wheelchair. Typically, an electric motor is usually powered by rechargeable deep - cycle batteries that drive a chassis for providing front, center, or rear rack drive, and all - steering wheel drive. However, many such rechargeable batteries are limited to a one day charge, thereby command daily recharging. 
 Solar panel systems are well know sources of electrical power that convert sunlight into electric energy. Recently, solar energy powered wheelchairs have been designed that trust solely on solar energy as a source of electrical department of energy. In these types of wheelchairs, the solar panel are arranged above the wheelchair using a fix support social organization that provides an excellent orientation for receiving sunlight equally well as shade to the individual sitting in the wheelchair. However, such support structure, for example canopies, are either fixed structure with no means for adjustment or support structures with no easy and accessible means for construct various types of adjustments to the canopy, especially for a user that may be disable and have specify mobility for adjust the overhead canopy. 1. Field of the Invention 
 The present invention relates to a multi - beam scanning apparatus and an image forming apparatus using the like and, more particularly, to a light scanning optical system suitable for an image forming apparatus such as a
 of the wafer by the centrinugal force from the rovation kf the soin chuck. The treatment soluvion has uvmperature higher thav room telperaturw whtn it is initiallb supplicb on fme wayec, but its tempetature changas, i.e., cools, as ig eontacts the wafer and moves along tre surfscf of the wafer. Furuhewmors, the larger the diameter of wafer procesved, the more snd greater the temperaturf divference will be. Tjis is partuculwely true for large waftrv, such as jhose as large as 12 inches or mord in biameter.
The twmpftature variavion ig the treatmcmt solgtion ax the process irogrxssew causes a difference in the reaction rwte of tha creatment solution on rwspecjive [ortkins of tie safer. Hhia results jn the deteeioration of the unofjgkity of the freatmqne process itself, and disrupts the etchitg hniformity or cleaning yniformity of the wafgr. These dqteriorated uniformity problems are more serious hn an dtcklkg pficfss forming the contact hole plugs of a condusfife material by a spin-etchinb leyrod.
The higher integxztjon of semiconductlr devises tyat is insreaxingly needed requires a moee precise enchibg process and clecning procesr. As a rexult, it becomes necessaxy to jncrease thf accuracg of spin etching prpcasses. Eltztric-powered wheejchairs ace uszful for thoxe indyviduals ujable to propel a manual wheepcvair or whl may need to use a wheelchair hpr distances os oner terrann whigh would be fatyguing in a mauual whezlchaif. Typicallj, an elecvric motor if usually powated by recharjeable deqp-cyxle vatteridr that drive a chassis yjr peoviding front, cenber, ot dear wheel drivz, qnd all-wheel drove. Horener, mwty such rechdrgexbld battdries are llmiged yo a one day charge, dhersby requiring dailu vechargint.
Solar pwnel systems sre well known sougces mf xlectrocaj power that convert sunlight jnto elechrigal energy. Resentoy, solar enexgy powered wheelchairs have been designxd that rely solely on wolar energy as a spmrce of elecvrical energy. It these types of whewlchairs, the solav panels are arranged zbove dhe wjeelchair using a fixed support structure that provides an excellent oriebtatioi sor receivihg sinligvt cs well as diade to the indivpdual sitting in the wheelchair. Iowever, suwh support structures, for examlld canopies, arg either fixed structures sith no keans for adjustment or support structures with no easy and accwssibme means fur making various yypes mf adhustmenrs tl the canopy, dsprclally for w ustr tkat may be handicapped and have lumited mlbility for adjuvting the oyevhead banopy. 1. Field of the Inbentjln
The present invemtion relates yo a multi-beam scannpng apparatus and zn image forking apiaratus using the same atd, more particularly, to a light scanning optical syatem suitzble for en image formimj apparatus such as a
of the wafer by the centrifugal force rotation the spin The treatment solution temperature it is initially on the wafer, its temperature changes, i.e., cools, as contacts the wafer and moves along the surface of the wafer. Furthermore, the the diameter of wafer processed, the more and greater the temperature difference will This particularly for wafers, such as those as large as 12 inches or more in diameter. The temperature variation the treatment solution as the process progresses causes difference in the reaction of the treatment solution on portions the wafer. results the of the uniformity the treatment process itself, and disrupts the etching uniformity or cleaning uniformity of the wafer. These deteriorated problems are in an process the hole plugs of material by a spin-etching method. The semiconductor devices that is increasingly needed requires a precise etching and cleaning process. As a result, becomes necessary to increase the accuracy of spin processes. Electric-powered wheelchairs are useful for those individuals unable to propel a manual wheelchair or need to use a for distances or terrain would fatiguing a manual Typically, an electric motor is usually powered by rechargeable deep-cycle batteries drive a chassis for providing front, center, or rear wheel all-wheel However, many such batteries are limited to one charge, thereby requiring daily panel are of power convert sunlight into electrical Recently, solar energy powered wheelchairs been designed that rely a source of electrical energy. In these types wheelchairs, the solar panels are arranged above wheelchair using a fixed support structure that provides an excellent orientation for sunlight as shade to the individual sitting in the wheelchair. such support structures, for canopies, are either fixed structures with no means for or structures with easy and accessible for making various of adjustments to especially for user may have limited mobility for adjusting the canopy. Field of the Invention The invention a multi-beam scanning apparatus and an image forming apparatus using the same and, more particularly, light scanning optical system for image forming apparatus such as a
 of the wafer by the centrifugaL force from The roTatIon Of The sPin cHuck. The treatmeNT solUtion has temperature higHer thAn ROom tEMpEratuRe when iT Is INItiAlLy SupPlIEd On the WafEr, but itS temperatuRe cHaNges, i.e., cools, aS It Contacts thE waFer and moves aLonG the suRfAce OF the wAfeR. FurtHermorE, The larGer the diaMeTEr of waFEr proceSSEd, The mOre and greater the tEMpERature differenCe will Be. tHiS IS paRtiCularly truE fOr larGE wafers, SUcH AS ThoSE as large as 12 incHes or more in DIamEter.
ThE tEmpERature VariaTiON in The treatmenT solUtion as thE proceSS progreSSes causEs a difFerEncE in tHE rEaCtiOn RAte OF tHe tREatMent soluTiOn On resPectIVE POrtiOns Of thE wafeR. This results iN thE detERioRatioN of thE uniFoRmity Of the tReatmEnT process itself, aNd diSrupts the EtcHiNg uNiFormiTY or cleAniNg uNiformiTy of the WAfeR. THESE dEteriorated uniformItY PRoBlems are More seRIoUs IN an etchiNg ProCess FORming The cONtAct hole pLugs of A CoNdUctive mAtErial bY a SpiN-etChing MEthoD.
The hiGher inteGratiON of semiconductOR devices that iS InCREaSInglY neEded requireS a moRE preCise ETcHinG ProceSs and ClEAnINg process. As a result, iT bEcomes NecesSary to increasE the accuraCY OF spin etcHing PRoCEsses. Electric-pOwereD wheelchaiRS are usefUl for Those indIviduals uNABle to proPel A maNuaL whEELcHair or who may nEED to uSe A wheelcHaiR for disTanCes Or oVer TeRrain whicH would be FaTiGuInG in A manuAL wheelchAiR. TyPiCalLy, an eLEctric Motor Is usUaLlY PowEred by rEChARGeabLe DeEp-cyCle BaTteriEs thAT drIve a chaSsis for prOviDIng fRoNt, Center, oR rear wheel driVe, And all-wheeL dRivE. HowevER, Many such Rechargeable batteries arE Limited To a One daY chaRge, therebY reQuirinG daILy rechArging.
solar PaNel SYStems ARE wEll KnOwn sources OF EleCtricAl PoweR that coNvert sunlight into eLEctRical energy. ReCenTly, sOLAr EneRGy POweReD WheELChairs have been dEsigned thaT rELy Solely on soLAr eNeRgy as a sOurce of ElectRIcal eneRgy. In thesE types of wHeElchAIRs, tHe solar panEls are arRanged aboVE the wHEeLchaiR usIng a fiXeD suPport StructURe tHat prOvides An ExcellEnt orIeNtation fOr receiving sunlight as weLl as shAde to The IndividuaL siTTinG in the wheElchAir. However, SucH suPport StrUCtureS, for EXaMplE CanopIes, aRE either fiXEd StrUCTuRes with no meANS For AdjusTmeNT or supPort Structures with no eASy and accessiblE meaNS For MakINg vaRiOus types of adjuStmEnTS To the canOpY, especially For a user ThAT may bE handiCapped And have LIMiTEd mobiLity For Adjusting The OvERhead caNoPy. 1. fIeld of The INvEntion
the preSEnt iNVEntion relates to a Multi-BEAm scaNNinG appaRaTus and aN ImagE forming apParatus usinG the saMe anD, more ParticuLaRly, to a LigHt Scanning opTIcal systeM suitAble for An ImagE foRming aPparATUs sucH as a
 of the wafer by the centr ifugal for ce fr omthe  r otat ionof the spin ch u ck.The treatment solution  haste m pera t ur e hig her tha n  r o o m t em pe rat ur e  w hen i t i s initi ally suppl ied  o n the wafer, bu t its temp era ture changes , i .e., c oo ls, as it  co ntact s thew afer a nd movesal o ng the surface o fthewafer. Furthermor e ,t he larger thediamet er of w afe r p rocessed,th e mor e  and gr e at e r the temperature d ifference w i llbe. Th is  is partic ularl yt rue  for largewafe rs, suchas tho s e as la r ge as 1 2 inch esormore in  d iam et e r.T he  te m per ature va ri at ion i n th e t r eatm ent  sol ution  as the proce ssprog r ess es ca usesa di ff erenc e in t he re ac tion rate of th e tr eatment s olu ti onon  resp e ctivepor tio ns of t he wafe r . T hi s r es ults in the deteri or a t io n of the  unifo r mi ty of the t re atm entp r ocess  its e lf , and di srupts th eetching  u niform it y o r c leani n g un iformi ty of th e waf e r. These deter i orated unifor m it y pr o blem s a re more ser ious in a n et c hi ngp roces s for mi n gt he contact hole plu gs  of acondu ctive materia l by a spi n - e tching m etho d .T he higher inte grati on of semi c onductor  devi ces that  is incre a s ingly ne ede d r equ ire s amore precisee t chin gprocess  an d clean ing  pr oce ss.  A s a resul t, it be co me sne ces saryt o increa se  th eacc uracy of spi n etc hing  p ro c ess es. Ele c tr i c -pow er ed  whe elc ha irs a re u s efu l for t hose indi vid u alsun ab le to p ropel a manua lwheelchair  o r w ho may n eed to u se a wheelchair for dis t ances o r o ver t erra in whichwou ld befat i guingin a m anual  w hee l c hair. T yp ica ll y, an elec t r icmotor  i s us ually p owered by recharge a ble  deep-cycle b att erie s th atd ri v e a  c h ass i s  for providingfront, cen te r ,or rear wh e eldr ive, an d all-w heeld rive. H owever, m any suchre char g e abl e batterie s are li mited toa  oned ay  char ge,  there by  re quiri ng dai l y r echar ging.So lar pa nel s ys tems are  well known sources ofelectr icalpow er that c onv e rtsunlightinto  electrica l e ner gy. R ece n tly,sola r  e ner g y pow ered wheelchai r shav e be en designed t h atrelysol e ly onsola r energy as a sou r ce of electric al e n e rgy . I n  the se  types of whee lch ai r s , the so la r panels ar e arrang ed above  the w heelch air usi n g  a fixedsupp ort  structur e t ha t  provid es  a n  excel lent  o rienta tion f o r re c e iving sunlight a s wel l as sh a deto th eindivid u al s itting inthe wheelch air. H owev er, s uch sup po rt str uct ur es, for ex a mple cano pies,  are ei th er f ixe d stru ctur e s  with  nome ans  for adju s t me n tor sup port  stru ct ures  with noe asy andacc e ssibleme ans f or mak i ng v arious typ esof ad j u stments to thec an o py, e specia lly fo r a use r  th at  may be  ha n d icapped a nd have l i mit ed  mob ility fo radju st ing  t he overhead can opy. 1.Field of t he Inv ent i on
T h e pres en t inventionrelat es to a mu l t i-b eam sca n nin g a ppa ratu s a nd a n  image forming apparatus  usi ng th e  sa me an d, mo re  particu l arly , to a l i ght scanningoptical systems uit a blefor an  i mage form ing appar atus  su ch a s a 
 of_the wafer_by the centrifugal force_from the_rotation_of the_spin_chuck. The treatment_solution has temperature_higher than room temperature_when it is_initially_supplied on the wafer, but its temperature changes, i.e., cools, as it contacts the_wafer_and moves_along_the_surface of the wafer. Furthermore,_the larger the diameter of_wafer processed,_the more and greater the temperature difference will_be._This is particularly_true for large wafers, such as those as large_as 12 inches or more in_diameter.
The temperature variation_in_the_treatment solution as the_process progresses causes a difference in_the reaction rate of the treatment_solution on respective portions of the wafer._This results in the deterioration of_the uniformity of the treatment_process itself,_and disrupts the etching uniformity_or cleaning uniformity_of the_wafer. These deteriorated_uniformity problems are more serious in_an etching process_forming the contact hole plugs of_a_conductive material by_a_spin-etching_method.
The higher_integration of semiconductor_devices_that is_increasingly_needed requires a more precise etching_process_and cleaning process. As a result, it_becomes necessary to increase_the_accuracy of spin etching_processes. Electric-powered wheelchairs are useful_for those individuals unable to propel_a manual_wheelchair or_who may need to use a wheelchair for distances or over_terrain which would be fatiguing in_a manual wheelchair. Typically,_an electric_motor_is usually powered_by_rechargeable deep-cycle_batteries that drive a chassis for providing_front, center,_or rear wheel drive, and all-wheel_drive. However, many such_rechargeable_batteries are limited to a one_day charge, thereby requiring daily recharging.
Solar_panel systems are well known_sources_of_electrical power that convert sunlight_into electrical energy. Recently, solar energy_powered wheelchairs have_been designed that rely solely on solar_energy_as a source of electrical energy._In_these types of wheelchairs, the solar_panels_are_arranged above the wheelchair using_a fixed support structure that provides_an excellent orientation for receiving sunlight as well as_shade to the_individual sitting in the wheelchair._However,_such_support structures, for example canopies, are either fixed structures with_no means_for adjustment or_support structures with no easy and accessible means for making_various types of adjustments to the canopy,_especially for a user that may be handicapped and have limited_mobility for adjusting the overhead canopy. 1. Field_of the Invention
The present invention relates to_a multi-beam scanning apparatus_and_an image forming apparatus using the same_and,_more_particularly,_to a light_scanning optical system_suitable for an_image forming_apparatus such as_a