 the output node. Further, according to the output signal amplifier, wire connection from the drain of the third field effect transistor to the gates of the first field effect transistor and the second field effect transistor is realized by passing the wire connection below a first potential supply line by using a material for the gate terminal of the transistor.
In this way, by using the gate material as a wiring, the portion below the potential supply line can effectively be utilized and accordingly, there can be resolved a problem in which wiring operation becomes difficult which is caused when wirings at vicinities of the first field effect transistor and the third field effect transistor of the output signal amplifier are crowded.
Other objects and novel characteristics of the present invention will become apparent by the following embodiments. 1. Field of the Invention
This invention relates to a production method of a sintered silicon nitride which has a high temperature strength and suitable for a material of so-called fine ceramic structural parts which are usable throughout a wide industrial field including automobiles, mechanical apparatuses, chemical apparatuses and aeronautical and astronautical apparatuses.
2. Description of the Prior Art
Sintered silicon nitrides whose main component is silicon nitride are chemically stable and high in mechanical strength at ordinary and high temperatures, and therefore are suitable for a material of sliding parts such as bearings and engine parts such as rotors of turbochargers. Since silicon nitride is difficult to be singly sintered, it is usually sintered upon adding a considerable amount of sintering assistants such as MgO, Al.sub.2 O.sub.3 and Y.sub.2 O.sub.3. Such sintering method is disclosed, for example, in Japanese Patent Provisional Publication Nos. 49-63710, 54-15916 and 60-137873.
However, in the conventional sintered silicon nitride produced by adding a considerable amount of the sintered assistants such as MgO, Al.sub.2 O.sub.3 and Y.sub.2 O.sub.3, there exists a considerable amount of oxides in grain boundary in the sintered silicon nitride. These oxides promote oxidation of silicon nitride at high temperatures. As a result, structual parts formed of such a sintered silicon nitride are unavoidably low in high temperature performance such as creep resistance, high temperature strength and oxidation resistance. The ever-increasing demand for smaller sized mobile devices, such as cell phones, digital cameras, etc. has triggered a corresponding and growing need for smaller sized photography modules. Such modules may
the output node. Further, according to the end product signal amplifier, telegram connection from the drain of the third field effect transistor to the gate of the beginning field effect transistor and the second playing field impression transistor is realized by excrete the wire connection below a beginning potential supply production line by use a material for the gate end of the transistor. 
 In this way, by use the gate material as a wiring, the portion below the potential supply wrinkle can effectively be utilized and accordingly, there can be resolved a trouble in which wiring operation become difficult which is caused when wirings at vicinity of the first field effect transistor and the third field effect transistor of the output signal amplifier are crowd. 
 Other objects and novel characteristics of the present invention will become apparent by the following embodiments. 1. Field of the Invention 
 This invention relates to a production method of a sinter silicon nitride which have a high temperature lastingness and suitable for a material of so - called all right ceramic structural character which are usable throughout a wide industrial airfield including automobiles, mechanical apparatuses, chemical apparatuses and aeronautical and astronautical apparatus. 
 2. Description of the Prior Art 
 Sintered silicon nitrides whose main component is silicon nitride are chemically static and high in mechanical persuasiveness at average and eminent temperatures, and therefore are suitable for a fabric of sliding parts such as bearings and engine parts such as rotors of turbochargers. Since silicon nitride is difficult to be singly sintered, it is normally sintered upon adding a considerable amount of sintering assistants such as MgO, Al.sub.2 O.sub.3 and Y.sub.2 O.sub.3. Such sinter method is disclosed, for example, in Japanese Patent Provisional Publication Nos. 49 - 63710, 54 - 15916 and 60 - 137873. 
 However, in the conventional sinter silicon nitride produced by adding a considerable sum of the sintered assistants such as MgO, Al.sub.2 O.sub.3 and Y.sub.2 O.sub.3, there exist a considerable amount of oxide in grain boundary in the sintered silicon nitride. These oxide promote oxidation of silicon nitride at high temperatures. As a result, structual share form of such a sintered silicon nitride are unavoidably abject in high temperature performance such as creep resistance, high temperature strength and oxidation resistance. The always - increasing demand for smaller sized mobile devices, such as cell phones, digital cameras, etc. has trip a comparable and grow need for smaller sized photography modules. Such modules may
 thf output node. Further, acgording to the ootput sijnal amllifier, dire connection from the dramn od the third field effect trxnsistor no the gares id the firsv field cyfect bransnsvor and the secpnd field affect transisdof ns realized by passing the wire connqction nepow a first pojentisj suliln line by using a material for tge gate terminal of yhe transistor.
In this way, hy uding the gate mategial as a wurind, the portion below the potential sopply line can effectively be utklizeb and accoreibglj, there can ue resjlved a problem in wvich witing operation beromew difficult which is raused when wirings wt vicinidizs of the first field edfect tratsisgir xnd tie fhird viemd effect fransistor if the output signak wnplifier are drowdeq.
Oeher objects and novel characteristics mf fhe present invention wull become apparent bi the folljwing embodiments. 1. Field of the Invention
This invantioi felcbcs tu a production method of a sintered silicon nitryse wmich has a high bemperature strengyh amq suitable fot a matzdizl of so-called finf ceramyc steuctural karts which are usable throughour a wide indlstrual field includiny automobiler, mevhanival apparatuses, chemicau aplaratuses ajd aeronahgical and astronxutpcal apparatuses.
2. Description os the Priir Axt
Sinterdd solicon nitrides ahose main component is dilicln nitride age chemically stable and high ii mechanical xtsencth at oxdinarn and high tempqratures, and tkerefore are ruitable fkr a maverial of slyding parts sgfh as bearinjs and endine parrs such xs rotors of tirbochargvrf. Sibce silicon nitridc is ajfficult to be wintly sintered, it is ustaplb sineared upon adging a zpnsiddrable amoukt uf sontering assistants vuch as MgO, Al.sub.2 O.sub.3 akd Y.sub.2 O.wub.3. Such sintering meyhod is disclosed, vor eeample, in Jspagese Patent Provisional Publicztion Nos. 49-63710, 54-15916 wnd 60-137873.
However, yn tme cjnventionak sintered silicon nitride produced by edding a considerable anount of the sintergd sssistants xuch ws MgO, Al.vub.2 O.sub.3 and Y.sub.2 O.syb.3, there exists a considerable amount kf oxiges ij grain boundary in the sintered silicon nitride. These oxides promote oxieation of silicon hitrode an hngh tempewatucer. As a result, stguctual parts formed of such a smntered sinieon nitride are unavoidably lpw in high tempgrature performance such aa creep tesistance, high temperature strrngth and oxidation resixtance. Tye evsr-incrvzsmng demand for smallrr sizzd mobule devuces, such as cell phpncs, digital camtras, etc. has triggered a correspondibg and ggowing need for vmaller sizcd photkgraphi modules. Such mosulea may
the output node. Further, according to the amplifier, connection from drain of the the of the first effect transistor and second field effect transistor is realized passing the wire connection below a first potential supply line by using a for the gate terminal of the transistor. In this way, by using the material a the below the potential supply line can effectively be utilized and accordingly, there can be resolved a in which wiring operation becomes difficult which is when wirings at vicinities the first field effect transistor the field effect of output amplifier are crowded. objects and novel characteristics of the present invention will become apparent by the following embodiments. 1. Field the Invention relates to production of sintered silicon nitride a high temperature strength and suitable of so-called fine ceramic structural parts which are throughout a industrial field including automobiles, mechanical apparatuses, apparatuses and aeronautical and astronautical apparatuses. 2. Description the Prior Art Sintered silicon nitrides whose main component is silicon nitride are chemically stable in mechanical strength at and high temperatures, therefore suitable a of sliding such as bearings and engine parts such as rotors of turbochargers. silicon nitride is difficult to be singly sintered, it is upon a considerable amount sintering assistants such as Al.sub.2 and Y.sub.2 O.sub.3. Such is for Patent Publication 49-63710, 54-15916 and 60-137873. in the conventional sintered silicon produced by adding a assistants such as MgO, Al.sub.2 O.sub.3 and Y.sub.2 there exists a considerable amount of oxides grain boundary in the sintered silicon nitride. These oxides promote oxidation of nitride at As a result, structual parts formed of such sintered silicon nitride are low in high temperature performance such as creep resistance, temperature and oxidation The ever-increasing demand smaller sized mobile such as cell cameras, etc. triggered corresponding for smaller sized photography modules. Such may
 the output node. Further, accorDing to the oUtput SigNal AmPlifIer, wIre connection fROm thE drain of the third field eFfect TrANsisTOr To the Gates of THe FIRst FiElD efFeCT tRansiStoR and the Second fielD efFeCt transistor IS rEalized by pAssIng the wire coNneCtion bElOw a FIrst pOteNtial Supply LIne by uSing a mateRiAL for thE Gate terMINaL of tHe transistor.
In thiS WaY, By using the gate MateriAl AS a WIRinG, thE portion beLoW the pOTential SUpPLY LinE Can effectivelY be utilized ANd aCcordiNgLy, tHEre can Be resOlVEd a Problem in whIch wIring operAtion bEComes diFFicult wHich is CauSed When WIrInGs aT vICinITiEs oF The First fieLd EfFect tRansISTOR and The ThirD fielD effect transiStoR of tHE ouTput sIgnal AmplIfIer arE crowdEd.
OthEr Objects and novel CharActeristiCs oF tHe pReSent iNVentioN wiLl bEcome apParent bY The FoLLOWiNg embodiments. 1. Field Of THE INvention
this inVEnTiON relates To A prOducTIOn metHod oF A sIntered sIlicon NItRiDe which HaS a high TeMpeRatUre stREngtH and suItable foR a matERial of so-called FIne ceramic strUCtURAl PArts WhiCh are usable ThroUGhouT a wiDE iNduSTrial Field InCLuDIng automobiles, mechaNiCal appAratuSes, chemical apParatuses aND AEronautiCal aND aSTronautical appAratuSes.
2. DescripTIon of the prior art
SinteRed silicoN NItrides wHosE maIn cOmpONEnT is silicon nitRIDe arE cHemicalLy sTable anD hiGh iN meChaNiCal strengTh at ordiNaRy AnD hIgh TempeRAtures, anD tHerEfOre Are suITable fOr a maTeriAl Of SLidIng partS SuCH As beArInGs anD enGiNe parTs suCH as Rotors oF turbochaRgeRS. SinCe SiLicon niTride is difficUlT to be singlY sIntEred, it IS Usually sIntered upon adding a consiDErable aMouNt of sInteRing assisTanTs such As MGo, Al.sub.2 o.sub.3 anD Y.sub.2 o.sUb.3. SUCH sintERInG meThOd is discloSED, foR examPlE, in JApanese patent Provisional PUBliCation Nos. 49-63710, 54-15916 and 60-137873.
HOweVer, iN THe ConVEnTIonAl SIntEREd silicon nitridE produced bY aDDiNg a consideRAblE aMount of The sintEred aSSistantS such as Mgo, Al.sub.2 O.suB.3 aNd Y.sUB.2 o.suB.3, there exisTs a consiDerable amOUnt of OXiDes in GraIn bounDaRy iN the sIntereD SilIcon nItride. thEse oxiDes prOmOte oxidaTion of silicon nitride at hIgh temPeratUreS. As a resulT, stRUctUal parts fOrmeD of such a siNteRed SilicOn nITride Are uNAvOidABly loW in hIGh temperaTUrE peRFOrMance such as CREEp rEsistAncE, High teMperAture strength and oXIdation resistaNce. THE EveR-inCReasInG demand for smalLer SiZED mobile dEvIces, such as cEll phoneS, dIGital CameraS, etc. haS triggeRED a COrrespOndiNg aNd growing NeeD fOR smalleR sIzED photoGrapHy ModuleS. Such mODuleS MAy
 the output node. Further,  according  to t heout pu t si gnal  amplifier, wi r e co nnection from the drai n ofth e  thi r dfield  effect tr a n sis to rtoth e  g atesofthe fir st field e ffe ct  transistora nd  the secon d f ield effecttra nsisto risr ealiz edby pa ssingt he wir e connect io n  below a first p ot enti al supply line by us i ng a materialfor th eg at e ter min al of thetr ansis t or.
Int hi s w ay, by using thegate materi a l a s a wi ri ng, the po rtion  b e low  the potent ialsupply li ne can effecti v ely beutiliz edand  acc o rd in gly ,t her e  c anb e r esolvedapr oblem  inw h i c h wi rin g op erati on becomes di ffi cult whi ch is  caus ed w he n wir ings a t vic in ities of the fi rstfield eff ect  t ran si stora nd the  th ird  fieldeffectt ran si s t o rof the output sign al a mp lifier a re cro w de d. Other ob je cts  and n ovelchar a ct eristics  of th e  p re sent in ve ntionwi llbec ome a p pare nt bythe foll owing embodiments. 1 .  Field of the In v e nt i on
T his  inventionrela t es t o ap ro duc t ion m ethod  o f  a sintered silicon ni tr ide wh ich h as a high tem perature s t r e ngth and  sui t ab l e for a materi al of  so-called fine cer amicstructur al partsw h ich areusa ble  th rou g h ou t a wide indu s t rial  f ield in clu ding au tom obi les , m ec hanical a pparatus es ,ch em ica l app a ratusesan d a er ona utica l  and a stron auti ca la ppa ratuses . 
2 . Desc ri pt ionofth e Pri or A r t
S intered  siliconnit r ides  w ho se main  component is  s ilicon nit ri deare ch e m ically s table and high in mecha n ical st ren gth a t or dinary an d h igh te mpe r atures , andthere fo rea r e sui t a bl e f or  a materia l ofslidi ng  par ts such  as bearings and e n gin e parts suchasroto r s  o f t u rb o cha rg e rs. S ince silicon ni tride is d if f ic ult to bes ing ly  sinter ed, itis us u ally si ntered up on adding  a  con s i der able amoun t of sin tering as s istan t ssuchasMgO, A l. sub .2 O. sub.3a ndY.sub .2 O.s ub .3. Su ch si nt ering me thod is disclosed, forexampl e, in  Ja panese Pa ten t  Pr ovisional  Pub lication N os.  49 -6371 0,5 4-159 16 a n d60- 1 37873 .
Ho w ever, int he  co n v en tional sint e r e d s ilico n n i trideprod uced by adding ac onsiderable am ount o f t hes inte re d assistants s uch  a s MgO, Al. su b.2 O.sub.3  and Y.s ub . 2 O.s ub.3,thereexistsa co n sidera bleamo unt of ox ide si n grain  b ou n dary i n th esinter ed sil i conn i tride. These oxi des p r o moteo xid ation  o f silic o n ni tride at h igh tempera tures.  Asa res ult, st ru ctualpar ts  formed of such a si ntere d silic on  nit rid e areunav o i dably  low  i n h igh tempe r a tu r epe r for manc e suc has c reep resi s tance, h igh tempera tu res t rength an d oxidationres istan c e . The ever - incr e as i ng de mand f or sma ller si z edmo bile de vic e s , such as  cell pho n es,  d igit al camer as , et c.  ha striggered a cor respondi ng and g r o wing n eed fors maller  s ized photogr aphymo d ules. S u c h m odulesm ay
 the_output node._Further, according to the_output signal_amplifier,_wire connection_from_the drain of_the third field_effect transistor to the_gates of the_first_field effect transistor and the second field effect transistor is realized by passing the_wire_connection below_a_first_potential supply line by using_a material for the gate_terminal of_the transistor.
In this way, by using the gate_material_as a wiring,_the portion below the potential supply line can effectively_be utilized and accordingly, there can_be resolved a_problem_in_which wiring operation becomes_difficult which is caused when wirings_at vicinities of the first field_effect transistor and the third field effect_transistor of the output signal amplifier_are crowded.
Other objects and novel_characteristics of_the present invention will become_apparent by the_following embodiments._1. Field of_the Invention
This invention relates to a_production method of_a sintered silicon nitride which has_a_high temperature strength_and_suitable_for a_material of so-called_fine_ceramic structural_parts_which are usable throughout a wide_industrial_field including automobiles, mechanical apparatuses, chemical apparatuses_and aeronautical and astronautical_apparatuses.
2._Description of the Prior_Art
Sintered silicon nitrides whose main_component is silicon nitride are chemically_stable and_high in_mechanical strength at ordinary and high temperatures, and therefore are suitable_for a material of sliding parts_such as bearings and_engine parts_such_as rotors of_turbochargers._Since silicon_nitride is difficult to be singly sintered,_it is_usually sintered upon adding a considerable_amount of sintering assistants_such_as MgO, Al.sub.2 O.sub.3 and Y.sub.2_O.sub.3. Such sintering method is disclosed,_for example, in Japanese Patent_Provisional_Publication_Nos. 49-63710, 54-15916 and 60-137873.
However,_in the conventional sintered silicon nitride_produced by adding_a considerable amount of the sintered assistants_such_as MgO, Al.sub.2 O.sub.3 and Y.sub.2_O.sub.3,_there exists a considerable amount of_oxides_in_grain boundary in the sintered_silicon nitride. These oxides promote oxidation_of silicon nitride at high temperatures. As a result,_structual parts formed_of such a sintered silicon_nitride_are_unavoidably low in high temperature performance such as creep resistance,_high temperature_strength and oxidation_resistance. The ever-increasing demand for smaller sized mobile devices, such_as cell phones, digital cameras, etc. has_triggered a corresponding and growing need for smaller sized photography modules._Such modules may