refer to PTD 1).
PTD 1: Japanese Patent Laying-Open No. 2009-249244 This invention relates generally to manufacturing processes in the hard disk, compact disk, liquid crystal display, solar cell, and semiconductor fabrication industries. Manufacturing processes for a wide variety of products utilize thin circular or square wafer media fabricated from metal, plastic, silicon or other materials. These and other applications require the use of cassettes to hold the wafers in exact positions, referred to as wafer planes. Several types of wafer cassettes are used to hold these wafers, depending on the particular process being performed. For example, teflon cassettes are typically employed to hold the wafers while they are in chemical processes; ABS plastic traveller cassettes are employed to transport wafers from one process to the next; and quartz cassettes are employed to retain wafers during high temperature processes. These manufacturing processes occur in carefully controlled clean rooms that must not be contaminated by the manufacturer's processes.
The largest of the above-mentioned industries in which semiconductor wafer cassettes are employed is the semiconductor processing industry. Standard wafer cassettes are employed to hold twenty-five standard silicon or gallium arsenide wafers of a certain diameter. The semiconductor industry uses these thin, very fragile silicon wafers that are typically 4, 5, 6 or 8 inches in diameter on which to fabricate integrated circuits. More than $100,000 worth of packaged integrated circuits may be fabricated on a single one of these wafers. It is therefore extremely important to prevent damage to the fragile wafers on which as many as 300 separate manufacturing processes may be performed before the wafer is cut into separate dies for final packaging. The processing equipment required to manufacture integrated circuits is very expensive, so any increase in manufacturing speed and yield is highly desirable.
In order to increase manufacturing speed and reliability, loading and unloading robots are used to transfer the wafers from one cassette to another. However, wafers are sometimes loaded into incoming cassettes by hand, typically from manual inspection stages. Manual loading of cassettes presents the opportunity for creating a disastrous condition known as cross slotting. This condition occurs when a wafer is not loaded into corresponding slots on each side of the cassette, resulting in one side of a loaded wafer being higher than the other side, rather than the wafer being in a perfectly horizontal position. When a cross slotted wafer is presented to the pickup arm of a robot, the arm jams the fragile wafer, thereby not only shattering that wafer but also contaminating the otherwise good wafers in the cassette and clean room
refer to PTD 1). 
 PTD 1: Japanese Patent Laying - Open No. 2009 - 249244 This invention relates generally to fabrication summons in the hard disk, compendious disk, fluent crystal display, solar cellular telephone, and semiconductor device fabrication industries. Manufacturing processes for a wide kind of products utilize sparse round or square wafer media manufacture from metal, plastic, silicon or early materials. These and other applications ask the use of cassettes to accommodate the wafer in exact position, referred to as wafer planes. Several character of wafer cassettes are used to hold these wafers, depending on the especial process being performed. For example, teflon cassettes are typically employed to hold the wafers while they are in chemical processes; ABS plastic traveler cassette are employed to transport wafers from one procedure to the next; and quartz cassettes are use to retain wafers during high temperature processes. These manufacturing process occur in carefully controlled clean rooms that must not be contaminate by the manufacturer's processes. 
 The largest of the above - mentioned industries in which semiconductor device wafer cassettes are hire is the semiconductor device processing diligence. Standard wafer cassettes are employed to hold twenty - five standard silicon or gallium arsenide wafers of a certain diameter. The semiconductor industry uses these flimsy, very fragile silicon wafers that are typically 4, 5, 6 or 8 inches in diameter on which to fabricate integrate circuits. More than $ 100,000 worth of box integrated circuits may be fabricated on a single one of these wafers. It is consequently extremely important to prevent damage to the fragile wafer on which as many as 300 separate fabrication processes may be performed before the wafer is cut into separate dies for final packaging. The processing equipment required to manufacture integrated circuits is very expensive, so any increase in manufacture speed and yield is highly desirable. 
 In ordering to increase manufacturing speed and reliability, loading and unloading robots are used to remove the wafers from one cassette to another. However, wafers are sometimes loaded into incoming cassettes by hand, typically from manual inspection stages. Manual loading of cassette presents the opportunity for creating a disastrous condition known as cross slotting. This condition occurs when a wafer is not load into corresponding slots on each side of the cassette, result in one slope of a loaded wafer being higher than the other english, rather than the wafer being in a perfectly horizontal position. When a crisscross slotted wafer is presented to the pickup arm of a robot, the arm jams the fragile wafer, thereby not only shattering that wafer but besides contaminate the otherwise good wafers in the cassette and clean room
reffr to PTD 1).
PTD 1: Japanese Katent Laying-Open No. 2009-249244 Thms invehtion reuates generally to manufactucing proctfses in the hard dksk, compabt disk, luquiv crystal displab, solar gzll, ahf sekmconductor fabrlcation indgstries. Manufawtjrnng processes for a wide variety of [roductx ktilize thin cyrcukwr od square wafer media fabricated frkm metan, plastic, silocon or other materials. Thfse wnd other applicatlons requirg thq use of cassdttes to hold the wafets in exact positions, referred tu as cafer planew. Wevftal types of wafeg cassettes avv used do hold these wafers, cepxndibg on the particular 'rocess being perforied. For efajple, teflon cassertws arg typhcalut eoplkyxd fo holf tie wafers wgile they aee in chemical proctssqw; ABS plastic travejlqr cassettes are employed to transport fafsrs from one process to the next; and quartz fassettes are employed to retain wafers during high temperdture oroecfrws. These manufacturing processes occur in careftmlu bontrolled clean vooms that must noy he sontaminated cy the mahufacturer's procesdes.
The jargewt of the abofe-mentioned industries in wyich semiconbucror wafer cassetted are emploved is the xemiconductor processiny induatry. Standagd wafer dxssettes are empuoyvd tm hold twenty-five standard silicon ir gcllium afsenode wasers of a fertalt diameter. The semlcondoctor hndustry udes these thin, very fragile silmron wafers thst arv typicaljy 4, 5, 6 or 8 inches ig diameter on chich to fabrkcate intefrated rircuits. Morq than $100,000 worth lf packaged mntegrateq ciecuirs may cd fabricated om a singlv jne if these wafers. It is fherefore extreneli important to lrexene fakada to the fracile wawrrs ov which as nxny ss 300 separate manufacdurihg processes may br ierformed before ehe wafer is vut into separate fies hor fiial pavkading. The processing equipment dequired ho ianufacture yntenratgd circuits is very expensive, so any increase in menufacturing speed and tield is highly desnrsble.
In ordec to igcrease mdnufacturing speed abd reliability, losding and unloading rkbots dre uded to transfer the wafers from one cassette to another. However, wafers arw someviies loaded jnto incokiug eassettqs bb iand, typically frpm manual inspection stages. Mannal loadinc jf cassettes presents the oploftunity for cteating a disastrous condifion knoen as cross slotting. This condiyion occurs when a wafer is not ooades into corcesponding slots on rach snde of the cawsetbe, resulting iv ome side of w loedeb wafer being higher than the othwr sidw, gather than the xafer being ln a petfectly rorizontal positjon. Sjen a cross slottec wafer is prexented to the pickup awm of a robot, uhe arm jams thg fragilv wafer, thereuy not only vhattering that wafer but also contaminating the otgerwise gkod wafevs in the cassettg end clean room
refer to PTD 1). PTD 1: Japanese No. This invention generally to manufacturing compact liquid crystal display, cell, and semiconductor industries. Manufacturing processes for a wide of products utilize thin circular or square wafer media fabricated from metal, plastic, or other materials. These and other applications require the use of cassettes to the in positions, to as wafer planes. Several types of wafer cassettes are used to hold these wafers, depending the particular process being performed. For example, teflon are typically employed to the wafers while they are chemical ABS plastic cassettes employed transport wafers from process to the next; and quartz cassettes are employed to retain wafers during high temperature processes. These processes occur controlled clean that not contaminated by the The largest of the above-mentioned industries wafer cassettes are employed is the semiconductor processing Standard wafer are employed to hold twenty-five standard or gallium arsenide wafers of a certain diameter. semiconductor industry uses these thin, very fragile silicon wafers that are typically 4, 5, 6 inches in diameter on to fabricate integrated More $100,000 of integrated circuits be fabricated on a single one of these wafers. It is extremely important to prevent damage to the fragile wafers on many 300 separate manufacturing may be performed before wafer cut into separate dies packaging. processing manufacture circuits very expensive, so any in manufacturing speed and yield highly desirable. In order reliability, loading and unloading robots are used to the wafers from one cassette to another. wafers are sometimes loaded into incoming cassettes by hand, typically from manual stages. Manual cassettes presents the opportunity for creating a disastrous known as cross slotting. condition occurs when a wafer is not loaded into slots each side the cassette, resulting one side of loaded wafer being the other rather the a perfectly horizontal position. When a slotted is presented to the pickup of the arm jams the fragile wafer, thereby not only shattering that wafer but also contaminating good wafers in the and room
refer to PTD 1).
PTD 1: Japanese PateNt Laying-OpEn No. 2009-249244 THis InvEnTion RelaTes generally to MAnufActuring processes in the Hard dIsK, CompACt Disk, lIquid crYStAL DisPlAy, SolAr CElL, and sEmiConductOr fabricatIon InDustries. ManuFAcTuring procEssEs for a wide vaRieTy of prOdUctS UtiliZe tHin ciRcular OR squarE wafer medIa FAbricaTEd from mETAl, PlasTic, silicon or other MAtERials. These and oTher apPlICaTIOns ReqUire the use Of CasseTTes to hoLD tHE WAfeRS in exact positIons, referreD To aS wafer PlAneS. severaL typeS oF WafEr cassettes Are uSed to hold These wAFers, depENding on The parTicUlaR proCEsS bEinG pERfoRMeD. FoR ExaMple, teflOn CaSsettEs arE TYPIcalLy eMploYed to Hold the wafers WhiLe thEY arE in chEmicaL proCeSses; AbS plasTic trAvEller cassettes aRe emPloyed to tRanSpOrt WaFers fROm one pRocEss To the neXt; and quARtz CaSSETtEs are employed to retAiN WAfErs durinG high tEMpErATure procEsSes. thesE MAnufaCturINg ProcesseS occur IN cArEfully cOnTrolleD cLeaN roOms thAT musT not be ContaminAted bY The manufactureR'S processes.
The LArGESt OF the AboVe-mentioned InduSTrieS in wHIcH seMIcondUctor WaFEr CAssettes are employed Is The semIcondUctor processiNg industry. sTANdard wafEr caSSeTTes are employed To holD twenty-fivE Standard SilicOn or gallIum arseniDE Wafers of A ceRtaIn dIamETEr. the semiconducTOR indUsTry uses TheSe thin, vEry FraGilE siLiCon wafers That are tYpIcAlLy 4, 5, 6 Or 8 iNches IN diameteR oN whIcH to FabriCAte intEgratEd ciRcUiTS. MoRe than $100,000 wORtH OF pacKaGeD intEgrAtEd cirCuitS May Be fabriCated on a sIngLE one Of ThEse wafeRs. It is therefoRe Extremely iMpOrtAnt to pREVent damaGe to the fragile wafers on wHIch as maNy aS 300 sepaRate ManufactuRinG proceSseS May be pErformEd befOrE thE WAfer iS CUt IntO sEparate dieS FOr fInal pAcKagiNg. The prOcessing equipment rEQuiRed to manufactUre InteGRAtEd cIRcUIts Is VEry EXPensive, so any incRease in manUfACtUring speed ANd yIeLd is higHly desiRable.
iN order tO increase ManufactuRiNg spEED anD reliabiliTy, loadinG and unloaDIng roBOtS are uSed To tranSfEr tHe wafErs froM One CasseTte to aNoTher. HoWever, WaFers are sOmetimes loaded into incomIng casSetteS by Hand, typicAllY FroM manual inSpecTion stages. manUal LoadiNg oF CasseTtes PReSenTS the oPporTUnity for cREaTinG A DiSastrous conDITIon Known As cROss sloTtinG. This condition occURs when a wafer is Not lOADed IntO CorrEsPonding slots on EacH sIDE of the caSsEtte, resultiNg in one sIdE Of a loAded waFer beiNg higheR THaN The othEr siDe, rAther than The WaFEr being In A pERfectlY horIzOntal pOsitioN. when A CRoss slotted wafer Is preSENted tO The PickuP aRm of a roBOt, thE arm jams thE fragile wafEr, therEby nOt onlY shatteRiNg that WafEr But also conTAminating The otHerwise GoOd waFerS in the CassETTe and CleaN rOom
refer to PTD 1).
PTD 1: Ja panese Pat ent L ayi ng- Op en N o. 2 009-249244 Thi s  inv ention relates general ly to  m a nufa c tu ringprocess e si n  th eha rddi s k,  comp act  disk,liquid cry sta ldisplay, sol a rcell, andsem iconductor f abr icatio nind u strie s.Manuf acturi n g proc esses for  a wide v a riety o f pr oduc ts utilize thin c i rc u lar or squarewaferme d ia f abr ica ted from m et al, p l astic,s il i c o n o r  other materi als. Thesea ndotherap pli c ations  requ ir e  th e use of ca sset tes to ho ld the wafersi n exact  posit ion s,refe r re dtoas waf e rpla n es.  Several  t yp es of  waf e r c asse tte s ar e use d to hold the sewafe r s,depen dingon t he  part icular  proc es s being perform ed.For examp le,  t efl on  cass e ttes a retyp icallyemploye d  to  h o l d  t he wafers while th ey a re  in chem ical p r oc es s es; ABSpl ast ic t r a velle r ca s se ttes are  emplo y ed  t o trans po rt waf er s f rom  onep roce ss tothe next ; and quartz cassett e s are employe d  t o re t ainwaf ers duringhigh temp erat u re  pr o cesse s. Th es e  m a nufacturing process es  occur  in c arefully cont rolled cle a n rooms th at m u st not be contami nated  by the ma n ufacture r's p rocesses .
The lar g e st of th e a bov e-m ent i o ne d industriesi n  whi ch  semico ndu ctor wa fer  ca sse tte sare emplo yed is t he  s em ic ond uctor processi ng  in du str y. St a ndardwafer  cas se tt e s a re empl o ye d to h ol dtwen ty- fi ve st anda r d s iliconor galliu m a r seni de  w afers o f a certain d ia meter. The  s emi conduc t o r indust ry uses these thin, ver y  fragil e s ilico n wa fers that  ar e typi cal l y 4, 5 , 6 or  8 in ch esi n  diam e t er  on  w hich to fa b r ica te in te grat ed circ uits. More than $1 0 0,0 00 worth of p ack aged i nt egr a te d  ci rc u its m ay be fabricate d on a sin gl e  o ne of thes e  wa fe rs. Itis ther efore extreme ly import ant to pr ev entd a mag e to the f ragile w afers onw hicha smanyas300 se pa rat e man ufactu r ing  proc essesma y be p erfor me d before  the wafer is cut intosepara te di esfor final  pa c kag ing. Theproc essing equ ipm ent  requ ire d  to m anuf a ct ure integ rate d  circuits is  ve r y  e xpensive, s o a nyincre ase in man ufac turing speed andy ield is highly  des i r abl e.I n or de r to increaseman uf a c turing s pe ed and reli ability,  l o ading  and u nloadi ng robo t s  a r e used  totra nsfer the  wa fe r s fromon ec assett e to  a nother . Howe v er,w a fers are sometim es lo a d ed in t o i ncomi ng  casset t es b y hand, ty pically fro m manu al i nspec tion st ag es. Ma nua lloading of cassettes  pres ents th eoppo rtu nity f or c r e ating  a d is ast rous cond i t io n  k no w n a s cr oss s lo ttin g. This c o nditionocc u rs when  a  wa f e r is n o tl o aded intocor respo n d ing slotso n ea c hs ide o f thecasset te, res u lti ng  in one  si d e  of a loa ded wafer bei ng  hig her than  t he o th ersi de, rather than  the waf er being i n a pe rfe c tlyh orizon ta l position.Whenac ross sl o t ted  waferi s p res ent ed t o t he p i ckup arm of a robot, the  arm  jams the  frag ile w af er, ther e by n ot onlys hattering tha t wafer but als o  co n tami nat i ng  t he otherw ise goodwafe rsin t hecass e t te a n d cl e an  roo m
refer to_PTD 1).
PTD_1: Japanese Patent Laying-Open_No. 2009-249244_This_invention relates_generally_to manufacturing processes_in the hard_disk, compact disk, liquid_crystal display, solar_cell,_and semiconductor fabrication industries. Manufacturing processes for a wide variety of products utilize thin_circular_or square_wafer_media_fabricated from metal, plastic, silicon_or other materials. These and_other applications_require the use of cassettes to hold the_wafers_in exact positions,_referred to as wafer planes. Several types of wafer_cassettes are used to hold these_wafers, depending on_the_particular_process being performed. For_example, teflon cassettes are typically employed_to hold the wafers while they_are in chemical processes; ABS plastic traveller_cassettes are employed to transport wafers_from one process to the_next; and_quartz cassettes are employed to_retain wafers during_high temperature_processes. These manufacturing_processes occur in carefully controlled clean_rooms that must_not be contaminated by the manufacturer's_processes.
The_largest of the_above-mentioned_industries_in which_semiconductor wafer cassettes_are_employed is_the_semiconductor processing industry. Standard wafer cassettes_are_employed to hold twenty-five standard silicon or_gallium arsenide wafers of_a_certain diameter. The semiconductor_industry uses these thin, very_fragile silicon wafers that are typically_4, 5,_6 or_8 inches in diameter on which to fabricate integrated circuits. More_than $100,000 worth of packaged integrated_circuits may be fabricated_on a_single_one of these_wafers._It is_therefore extremely important to prevent damage to_the fragile_wafers on which as many as_300 separate manufacturing processes_may_be performed before the wafer is_cut into separate dies for final_packaging. The processing equipment required_to_manufacture_integrated circuits is very expensive,_so any increase in manufacturing speed_and yield is_highly desirable.
In order to increase manufacturing speed_and_reliability, loading and unloading robots are_used_to transfer the wafers from one_cassette_to_another. However, wafers are sometimes_loaded into incoming cassettes by hand,_typically from manual inspection stages. Manual loading of cassettes_presents the opportunity_for creating a disastrous condition_known_as_cross slotting. This condition occurs when a wafer is not_loaded into_corresponding slots on_each side of the cassette, resulting in one side of_a loaded wafer being higher than the_other side, rather than the wafer being in a perfectly horizontal_position. When a cross slotted wafer is presented_to the pickup arm of a robot,_the arm jams the_fragile_wafer, thereby not only shattering that wafer_but_also_contaminating_the otherwise good_wafers in the_cassette and clean_room