 from the standpoint of achieving adequate flatness and efficiency owing to large relative displacements between the turntable 12 and the top ring 13 as well as their high relative speeds; however, surface roughness of the polished workpiece tends to be higher than desirable. To produce a polished workpiece of better surface quality, consideration may be given to using two turntables which are operated by varying the abrading qualities of the polishing cloths, rotational speeds and types of polishing solutions. However, as mentioned above, the diameter of the turntable is larger than twice that of the workpiece diameter, and each apparatus takes up a large floor space area which leads to higher facility costs. These problems becomes more ignorable as the industry seeks larger diameter substrates.
While it is possible to use one turntable to produce a superior surface quality by varying the type of polishing solution and lowering the rotational speed, for example, it is obvious that such an approach leads not only to a potential increase in the cost of polishing solution but to inevitable lowering in the production efficiency due to a prolonged operation.
The conventional method also has some problems in the cleaning process when scrubbing follows the use of abrasive particles, not only because of the inherent difficulties of removing small particles in submicron ranges but also because of the ineffective cleaning when there is a strong affinity between the workpiece and the particles.
Therefore, there has long been a need in the semiconductor device manufacturing industry for an efficient polishing method and facility which would enable to produce substrates of high surface qualities, such as flatness, smoothness and cleanliness, in a compact and low cost apparatus. Molecular therapy of disease often involves the administration of nucleic acid to the cells of interest in order to confer a therapeutic benefit. Most commonly, recombinant viruses are engineered which take advantage of the natural infectivity of viruses and their ability to transport heterologous nucleic acid (transgene) to a cell. Widespread use of such recombinant viral vectors depends on strategies for the design and production of such viruses.
Most attempts to use viral vectors for gene therapy have relied on retrovirus vectors, chiefly because of their ability to integrate into the cellular genome. However, the disadvantages of retroviral vectors are becoming increasingly clear, including their tropism for dividing cells only, the possibility of insertional mutagenesis upon integration into the cell genome, decreased expression of the transgene over time, rapid inactivation by serum complement, and the possibility of generation of replication-competent retroviruses (Jolly, D., Cancer Gene Therapy 1:51-64, 1994; Hodgson,
from the standpoint of achieving adequate flatness and efficiency owing to big proportional displacements between the turntable 12 and the top ring 13 equally well as their high proportional speeds; however, surface rowdiness of the dressed workpiece tends to be high than desirable. To produce a polished workpiece of good surface timbre, consideration may be given to using two turntables which are operated by varying the abrading quality of the polishing cloths, rotational speeds and type of polishing solutions. However, as mentioned above, the diameter of the turntable is larger than twice that of the workpiece diameter, and each apparatus remove up a large floor space area which leads to higher adeptness costs. These problems becomes more ignorable as the industry seeks larger diameter substrate. 
 While it is possible to use one turntable to produce a superior surface quality by varying the type of polishing solution and lowering the rotational focal ratio, for example, it is obvious that such an approach lead not merely to a potential increase in the cost of polish solution but to inevitable lowering in the production efficiency due to a prolonged operation. 
 The conventional method acting also has some problems in the cleaning process when scrubbing follows the use of abrasive particles, not only because of the inherent difficulties of murder small atom in submicron ranges but also because of the ineffective cleaning when there is a strong affinity between the workpiece and the particles. 
 consequently, there has long been a need in the semiconductor device manufacturing industry for an efficient polishing method and facility which would enable to produce substrate of high airfoil qualities, such as flatness, smoothness and cleanliness, in a compendious and low cost apparatus. Molecular therapy of disease often involves the presidency of nucleic acid to the cells of pastime in order to confer a therapeutic benefit. Most commonly, recombinant viruses are mastermind which take advantage of the natural infectivity of viruses and their ability to transport heterologous nucleic acid (transgene) to a cell. Widespread use of such recombinant viral vectors depends on scheme for the design and production of such virus. 
 Most attempts to use viral vectors for gene therapy have relied on retrovirus vectors, chiefly because of their ability to integrate into the cellular genome. However, the disadvantage of retroviral vectors are becoming increasingly clear, including their tropism for dividing cells only, the possibility of insertional mutagenesis upon consolidation into the cell genome, decreased expression of the transgene over time, rapid inactivation by serum complement, and the possibility of generation of replication - competent retrovirus (Jolly, D., Cancer Gene Therapy 1:51 - 64, 1994; Hodgson,
 frlm the standpoint of achleving adequate yoatnesv and sfficienzy owing to large relative dmsplqcemebts between the turntacle 12 and nhe top rung 13 qs well as their hlyh remwtivz wpeeds; however, surface rmughness of tha oopished workpiece tends to be higher than drslrable. To prodoce a [oliahed workpiece of better surface qhality, bonsideration may be given to using two turjtabpes which are operwted by varijng rhe abrading qualities of the poliahing cloths, rotational speeds xnd tvpes of polusyinh solutions. Ioweveg, as mentioned above, dhe diaketer of the tmrntaule us larger than twice vhat of the workpiecg diameter, aud each apparatus takws up a larce fuior spzcx adea whlch leads to gigher facioity costs. These prpbjvks becomes mkre iggowable as the industry seeks larger diamtter aubstrates.
While it is pissible to use one tutntable to produce a superior surface quality by varying tha typx uf kooishivt dolution and lowering the rotational speed, fow ecakple, it is obvlous that such an sporpwch leads not only ck z potential increade in tre cowt of polyshimg solution but to inevitaboe lowering pn tye production effieiency due tu a krolonbed operation.
The convencional method alsl has soms problems in the clvanitg process when scrubbing sollows tie usz of abrxsivg partisles, not ojly bcwause of the inherfnt dnfficglties of gemoving small particles in submicron ranges nud anso becabse of the ineffectyve cleaning wken therz is a strong afrinity uetween the rorkpiece and jhe particles.
Vherefore, theee hqs long ceen a need in the semibouductor dwvice manufacturinn indosfry for an effienebt polishing meyhoa agd fecilief which woulg enxbld to pfoduce subsbrages pf high surface qualhtiea, such as flatness, sioothnesw and clqanliness, in s compact and low fost epparavus. Mokecolar therapy of disease often ihvolves tje wdministratijn on nusleic acid to the cells of interest in order to cinfer a therapeutix benefit. Most commpkly, recombinent viwuses are engineered which taje advantage of tme natural infectivity of visuses and their ability to transport heterologous nucleic acid (transgene) to a xell. Wmdqspread use of xuch gecjkbinane vicau vectors dependx on strategies for the design end producdijn of such viruses.
Most attemltr to use virau vectors for gene theraly have telied on retrovirus vectors, choefly because of their anility to intefrate phtu the cellular genpme. Hocever, rhe disqdvaktages of retruvitap vectors are bzcoming increasingly clear, includung thwig tropism for ditiding cells unly, jhe possybility of inserfionzp mutxgenesis upon integration imto the cell genome, gesreased expreswpon of the trsnsgene over time, repid inactivdtion by serum complement, and the possibility of geheration kf repligation-competent rgtcoviruses (Jolly, D., Cancer Gqne Therxpy 1:51-64, 1994; Hodgsot,
from the standpoint of achieving adequate flatness owing large relative between the turntable 13 well as their relative speeds; however, roughness of the polished workpiece tends be higher than desirable. To produce a polished workpiece of better surface quality, may be given to using two turntables which are operated by varying the qualities the cloths, speeds and types of polishing solutions. However, as mentioned above, the diameter of the turntable is than twice that of the workpiece diameter, and apparatus takes up a floor space area which leads higher costs. These becomes ignorable the industry seeks diameter substrates. While it is possible to use one turntable to produce a superior surface quality by the type solution and the speed, example, it is such an approach leads not only increase in the cost of polishing solution but inevitable lowering the production efficiency due to a operation. The conventional method also has some problems the cleaning process when scrubbing follows the use of abrasive particles, not only because of difficulties of removing small in submicron ranges also of ineffective when there a strong affinity between the workpiece and the particles. Therefore, there long been a need in the semiconductor device manufacturing industry efficient method and facility would enable to produce of surface qualities, such as and in low apparatus. therapy of disease often the administration of nucleic acid the cells of interest therapeutic benefit. Most commonly, recombinant viruses are engineered take advantage of the natural infectivity of and their ability to transport heterologous nucleic acid (transgene) to a cell. use of viral vectors depends on strategies for the design production of such viruses. attempts to use viral vectors for gene therapy have on vectors, chiefly of their ability integrate into the genome. However, the retroviral vectors becoming clear, for dividing cells only, the possibility insertional upon integration into the cell decreased the transgene over time, rapid inactivation by serum complement, and the possibility of generation of (Jolly, D., Cancer Gene 1:51-64, Hodgson,
 from the standpoint of achievIng adequatE flatNesS anD eFficIencY owing to large rELatiVe displacements between The tuRnTAble 12 ANd The toP ring 13 as WElL AS thEiR hIgh ReLAtIve spEedS; howeveR, surface roUghNeSs of the polisHEd Workpiece tEndS to be higher tHan DesiraBlE. To PRoducE a pOlishEd workPIece of Better surFaCE qualiTY, considERAtIon mAy be given to using tWO tURntables which aRe operAtED bY VAryIng The abradinG qUalitIEs of the POlISHIng CLoths, rotationAl speeds and TYpeS of polIsHinG SolutiOns. HoWeVEr, aS mentioned aBove, The diametEr of thE TurntabLE is largEr than TwiCe tHat oF ThE wOrkPiECe dIAmEteR, And Each appaRaTuS takeS up a LARGE floOr sPace Area wHich leads to hiGheR facILitY costS. ThesE proBlEms beComes mOre igNoRable as the indusTry sEeks largeR diAmEteR sUbstrATes.
WhiLe iT is PossiblE to use oNE tuRnTABLe To produce a superior SuRFAcE quality By varyINg ThE Type of poLiShiNg soLUTion aNd loWErIng the roTationAL sPeEd, for exAmPle, it iS oBviOus That sUCh an ApproaCh leads nOt onlY To a potential inCRease in the cosT Of POLiSHing SolUtion but to iNeviTAble LoweRInG in THe proDuctiOn EFfICiency due to a prolongEd OperatIon.
ThE conventional Method also HAS Some probLems IN tHE cleaning proceSs wheN scrubbing FOllows thE use oF abrasivE particleS, NOt only beCauSe oF thE inHEReNt difficultieS OF remOvIng smalL paRticles In sUbmIcrOn rAnGes but alsO because Of ThE iNeFfeCtive CLeaning wHeN thErE is A stroNG affinIty beTweeN tHe WOrkPiece anD ThE PArtiClEs.
therEfoRe, There Has lONg bEen a neeD in the semIcoNDuctOr DeVice manUfacturing indUsTry for an efFiCieNt poliSHIng methoD and facility which would eNAble to pRodUce suBstrAtes of higH suRface qUalITies, suCh as flAtnesS, sMooTHNess aND ClEanLiNess, in a comPACt aNd low CoSt apParatus. molecular therapy of DIseAse often involVes The aDMInIstRAtIOn oF nUCleIC Acid to the cells oF interest iN oRDeR to confer a THerApEutic beNefit. MoSt comMOnly, recOmbinant vIruses are EnGineEREd wHich take adVantage oF the naturAL infeCTiVity oF viRuses aNd TheIr abiLity to TRanSport HeteroLoGous nuCleic AcId (transgEne) to a cell. Widespread use Of such RecomBinAnt viral vEctORs dEpends on sTratEgies for thE deSigN and pRodUCtion Of suCH vIruSEs.
MosT attEMpts to use VIrAl vECToRs for gene thERAPy hAve reLieD On retrOvirUs vectors, chiefly bECause of their abIlitY TO inTegRAte iNtO the cellular geNomE. HOWEver, the dIsAdvantages oF retroviRaL VectoRs are bEcominG increaSINgLY clear, InclUdiNg their trOpiSm FOr dividInG cELls onlY, the PoSsibilIty of iNSertIONal mutagenesis upOn intEGRatioN IntO the cElL genome, DEcreAsed expresSion of the trAnsgenE oveR time, Rapid inAcTivatiOn bY sErum compleMEnt, and the PossiBility oF gEnerAtiOn of rePlicATIon-coMpetEnT reTroviruseS (jOlLY, D., caNCer gene theraPy 1:51-64, 1994; hodgSon,
 from the standpoint of ac hieving ad equat e f lat ne ss a nd e fficiency owin g  tolarge relative displac ement sb etwe e nthe t urntabl e  1 2 and  t he  to pr in g 13aswell as  their hig h r el ative speeds ;  h owever, su rfa ce roughness  of  the p ol ish e d wor kpi ece t ends t o  be hi gher than  d e sirabl e . To pr o d uc e apolished workpiec e  o f  better surfac e qual it y ,c o nsi der ation maybe  give n  to usi n gt w o  tu r ntables which  are operat e d b y vary in g t h e abra dingqu a lit ies of thepoli shing clo ths, r o tationa l  speeds  and t ype s o f po l is hi ngso l uti o ns . H o wev er, as m en ti onedabov e , t he d iam eter  of t he turntableislarg e r t han t wicethat  o f the  workp iecedi ameter, and eac h ap paratus t ake supalarge floorspa cearea wh ich lea d s t oh i g he r facility costs.Th e s eproblems  becom e smo r e ignora bl e a s th e indus trys ee ks large r diam e te rsubstra te s.
Whi le  it  is  poss i bleto use  one tur ntabl e  to produce as uperior surfa c eq u al i ty b y v arying thetype of p olis h in g s o lutio n and  l o we r ing the rotationalsp eed, f or ex ample, it isobvious th a t such anappr o ac h  leads not onl y toa potentia l  increas e inthe cost  of polis h i ng solut ion  bu t t o i n e vi table lowerin g in t he  produc tio n effic ien cydue  to  a  prolonge d operat io n. 
T he  co nvent i onal met ho d a ls o h as so m e prob lemsin t he  c l ean ing pro c es s when  s cr ubbi ngfo llows  the use  of abr asive par tic l es,no tonly be cause of thein herent dif fi cul ties o f removing  small particles in sub m icron r ang es bu t al so becaus e o f theine f fectiv e clea ningwh ent h ere i s astr on g affinity b etw een t he  wor kpieceand the particles. The refore, there  ha s lo n g  b een an eed  i n  th e semiconductor d evice manu fa c tu ring indus t ryfo r an ef ficient  poli s hing me thod andfacilitywh ichw o uld  enable to  produce  substrat e s ofh ig h sur fac e qual it ies , suc h as f l atn ess,smooth ne ss and  clea nl iness, i n a compact and low cos t appa ratus . M olecularthe r apy  of disea se o ften invol ves  th e adm ini s trati on o f  n ucl e ic ac id t o  the cell s  o f i n t er est in orde r t o c onfer  at herape utic  benefit. Most co m monly, recombi nant v iru ses areen gineered which  ta ke a dvantage  o f the natur al infec ti v ity o f viru ses an d their a bi l ity to  tra nsp ort heter olo go u s nucle ic  a c id (tr ansg en e) toa cell .  Wid e s pread use of suc h rec o m binan t  vi ral v ec tors de p ends  on strate gies for th e desi gn a nd pr oductio nof suc h v ir uses.
Most attemptsto us e viral  v ecto rsfor ge ne t h e rapyhave  r eli ed on ret r o vi r us  v e cto rs,chief ly  bec ause of t h eir abil ity to inte gr ate i nto th e  c e l lular geno me.  Howe v e r, the dis a dvan t ag e s ofretrov iral v ectorsa rebe cominginc r e asingly c lear, inc l udi ng  the ir tropi sm  for  d ivi di ng cells only,the poss ibilityo f  inser tio n al m u tagene si s upon integ ratio ni nto the c ell  genome ,  de cre ase d ex pre ssio n  of the transgene over t ime,  rapi d  in activ ation  b y serumc ompl ement, a n d the possibi lity of generat i ono f re pli c at io n-compete ntr etrov irus es(Jol ly,  D., C ance r  Gen e  T hera py 1:5 1-64 ,19 94; Hodgs on ,
 from_the standpoint_of achieving adequate flatness_and efficiency_owing_to large_relative_displacements between the_turntable 12 and_the top ring 13_as well as_their_high relative speeds; however, surface roughness of the polished workpiece tends to be higher_than_desirable. To_produce_a_polished workpiece of better surface_quality, consideration may be given_to using_two turntables which are operated by varying the_abrading_qualities of the_polishing cloths, rotational speeds and types of polishing solutions._However, as mentioned above, the diameter_of the turntable_is_larger_than twice that of_the workpiece diameter, and each apparatus_takes up a large floor space_area which leads to higher facility costs._These problems becomes more ignorable as_the industry seeks larger diameter_substrates.
While it_is possible to use one_turntable to produce_a superior_surface quality by_varying the type of polishing solution_and lowering the_rotational speed, for example, it is_obvious_that such an_approach_leads_not only_to a potential_increase_in the_cost_of polishing solution but to inevitable_lowering_in the production efficiency due to a_prolonged operation.
The conventional method_also_has some problems in_the cleaning process when scrubbing_follows the use of abrasive particles,_not only_because of_the inherent difficulties of removing small particles in submicron ranges but_also because of the ineffective cleaning_when there is a_strong affinity_between_the workpiece and_the_particles.
Therefore, there_has long been a need in the_semiconductor device_manufacturing industry for an efficient polishing_method and facility which_would_enable to produce substrates of high_surface qualities, such as flatness, smoothness_and cleanliness, in a compact_and_low_cost apparatus. Molecular therapy of_disease often involves the administration of_nucleic acid to_the cells of interest in order to_confer_a therapeutic benefit. Most commonly, recombinant_viruses_are engineered which take advantage of_the_natural_infectivity of viruses and their_ability to transport heterologous nucleic acid_(transgene) to a cell. Widespread use of such recombinant_viral vectors depends_on strategies for the design_and_production_of such viruses.
Most attempts to use viral vectors for gene_therapy have_relied on retrovirus_vectors, chiefly because of their ability to integrate into the_cellular genome. However, the disadvantages of retroviral_vectors are becoming increasingly clear, including their tropism for dividing cells_only, the possibility of insertional mutagenesis upon integration_into the cell genome, decreased expression of_the transgene over time,_rapid_inactivation by serum complement, and the possibility_of_generation_of_replication-competent retroviruses (Jolly,_D., Cancer Gene_Therapy 1:51-64, 1994;_Hodgson,