TRNG CAO NG NGH CNG NGH CAO H NITRNG CAO NG NGH CNG NGH CAO H NI

LP IN T 2

BI BO CO THC T ti: Tm hiu v quy trnh hn linh kin

Nhm thc hin gm cc thnh vin:1. 2. 3. 4. 5. Nguyn Thun Thng L Vn Thn Dng c Thng Hong Ngc Thnh Nguyn Vn Thnh

Di s hng dn ca thy: 1. Phan Vn Vng 2. Hong c Long

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TRNG CAO NG NGH CNG NGH CAO H NICng ngh ng gi b mt (SMT) Xu hng pht trin khng th khc ti Vit nam u thng 5/2008, ti H Ni s din ra hi ch trin lm v cng nghip in t. Khch tham quan trin lm s c c hi din kin nhng c my, nhng cng ngh ang ngy m gp phn vo s pht trin ca nn cng nghip in t ton cu. Theo thng tin do TH nhn c, cc hng sn xut thit b cho nn cng nghip in t s tp trung vo gii thiu cc dy truyn hn linh kin b mt. Nhn s kin ny chng ti xin gi ti qu c gi mt s khi nim v cng ngh tin tin ny vi mong mun rng chng ta s c nhng khi nim c bn khi tip xc vi cc c my lm nn s thnh cng cho bao tp on in t hng u th gii. Khi nim v cng ngh hn linh kin b mt (SMT) Cng ngh hn linh kin b mt l phng php gn cc linh kin in t trc tip ln trn b mt ca bo mch (PCB). Cc linh kin in t dnh ring cho cng ngh ny c tn vit tt l SMD. Trong cng nghip in t, SMT thay th phn ln cng ngh ng gi linh kin trn tm PCB xuyn l theo linh kin in t c c nh trn b mt PCB bng phng php xuyn l v hn qua cc b ch nng.

Lp rp linh kin trn PCB theo cng ngh xuyn l

Theo cng ngh SMT

Cng ngh SMT c pht trin vo nhng nm 1960 v c p dng mt cch rng ri vo cui nhng nm 1980. Tp on IBM ca Hoa k c th c coi l ngi i tin phong trong vic ng dng cng ngh ny. Lc linh kin in t phi c gia cng c kh nh thm mt mu kim loi vo hai u sao cho c th hn trc tip chng ln trn b mt mch in. Kch thc linh kin c gimKHOA IN T Page 10

TRNG CAO NG NGH CNG NGH CAO H NIxung kh nhiu v vic gn linh kin ln trn c hai mt ca PCB lm cho cng ngh SMT tr ln thng dng hn l cng ngh gn linh kin bng phng php xuyn l, cho php lm tng mt linh kin. Thng thng, mi linh kin c c nh trn b mt mch in bng mt din tch ph ch rt nh, v mt kia ca tm PCB linh kin cng ch c c nh bng mt chm kem hn tng t. V l do ny, kch thc vt l ca linh kin ngy cng gim. Cng ngh SMT c mc t ng ha cao, khng i hi nhiu nhn cng, v c bit lm tng cng sut sn xut. K thut gn chp - Cc hng khc nhau s hu nhng b quyt v c quyn cng ngh khc nhau khi ch to cc loi my gn chp trn dy truyn SMT. Tuy vy, nhng cng on t lc np liu cho ti lc thnh phm (bo c gn chp) th tng i ging nhau. Cc cng on bao gm: 1) qut hp kim hn (kem hn) ln trn bo mch trn vo cc v tr trn c m sn chn hn bng vng, thic-ch, bc2) gn chp, gn IC 3) gia nhit lm mt 4 ) kim tra v sa li. Qut hp kim hn Trn b mt mch in khng c l, nhng ni linh kin c gn vo, ngi ta m sn cc lp vt liu dn in nh thic-ch, bc hoc vng nhng chi tit ny c gi l chn hn (hay lp m hn). Sau , kem hn, thng thy di dng bt nho l hn hp ca hp kim hn (c thnh phn khc nhau, ty vo cng ngh v i tng hn) v cc ht vt liu hn, c qut ln trn b mt ca mch in. trnh kem hn dnh ln trn nhng ni khng mong mun ngi ta phi s dng mt dng c c bit gi m mt n kim loi (metal mask hoc stencil) lm bng mng mng thp khng g trn ngi ta gia cng, c thng nhng v tr tngKHOA IN T Page 10

TRNG CAO NG NGH CNG NGH CAO H NIng vi ni t chp trn bo mchbng cch ny, kem hn s c qut vo cc v tr mong mun. Nu cn phi gn linh kin ln mt cn li ca bo mch, ngi ta phi s dng mt thit b iu khin s t cc chm vt liu c tnh bm dnh cao vo cc v tr t linh kin. Sau khi kem hn c ph ln trn b mt, bo mch s c chuyn sang my t chp (pickand-place machine). Gn chp, gn IC Cc linh kin SMDs, kch thc nh, thng c chuyn ti ti dy truyn trn bng cha (bng giy hoc nha) xoay quanh mt trc no . Trong khi IC li thng c cha trong cc khay ng ring. My gp chip c iu khin s s g cc chip trn khay cha v t chng ln trn b mt PCB ni c qut kem hn. Cc linh kin mt di ca bo mch c gn ln trc, v cc chm keo c sy kh nhanh bng nhit hoc bng bc x UV. Sau bo mch c lt li v my gn linh kin thc hin nt cc phn cn li trn b mt bo. (mu mt n kim loi)

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(thit b gn chp SM421 ca Samsung

Sau khi qu trnh gp, gn linh kin hon tt, bo mch c chuyn ti l sy. u tin cc bo tin vo vng sy s b ni m nhit ca bo v mi linh kin tng i ng u v c nng ln mt cch t t. Vic ny lm gim thiu ng sut nhit khi khi qu trnh lp rp kt thc sau khi hn. Bo mch sau tin vo vng vi nhit ln c th lm nng chy cc ht vt liu hn trong kem hn, hn cc u linh kin ln trn bo mch. Sc cng b mt ca kem hn nng chy gip cho linh kin khng lch v tr, v nu nh b mt a l ca chn hn c ch to nh thit k, sc cng b mt s t ng iu chnh linh kin v ng v tr ca n. . Gia nhit lm mt C nhiu k thut dng cho vic gia nhit, bo mch sau qu trnh gp, gn. Nhng k thut m ta thng gp s dng n hng ngoi, kh nng. Trng hp c bit ngi ta c th s dng cht lng CF4 vi nhit si ln. k thut ny c gi l gia. Phng php ny khng cn l u tin s mt khi xy dng cc nh my. Hin nay ngi ta s dng nhiu kh nit cho hoc kh nn giu ni-t trong cc l i lu. D nhin, mi phng php c nhng u im v nhc im ring. Vi phng php dng IR, k s thit k phi b tr linh kin trn bo sao cho nhng linh kin thp hn khng ri vo vng ca cc linh kin cao hn. Nu ngi thit k bit trc c cc chu trnh nhit hoc qu trnh hn i lu th anh ta s d dng hn trong vic b tr cc linh kin gn trn bo. Vi mt s thit k, ngi ta phi hn th cng hoc lp thm cc linh kin c bit, hoc l t ng ha bng cch s dng cc thit b hng ngoi tp trung. Sau qu trnh hn cc bo mch phi c ra g b nhng phn vt liu hn cn dnh trn v bt k mt vin vt liu hn no trn b mt bo cng c th lm ngn mch ca h thng. Cc vt liu hn khc nhau c ra bng cc ha cht khc nhau c ty ra bng cc dung mi khc nhau. Phn cn li l dung mi ha tan c ra bng nc sch v lm kh nhanh bng khng kh nn. Nu khng ch trng ti hnh thc v vt liu hn khng gy

hin tng ngn mch hoc n mn, bc lm sch ny c th l khng cn thit, tit kim chi ph v gim thiu nhim cht thi. Kim tra v sa li Cui cng bo mch c a sang b phn kim tra quang hc pht hin li b st linh kin hoc sa cc liv tr ca linh kn. Trong trng hp cn thit, chng ta c th lp t thm mt s trm kim tra quang hc cho dy truyn cng ngh sao cho c th pht hin li sau tng mi cng on..

(hnh nh kim tra sn phm sau qu trnh hn nhit bng X-ray) cng on ny chng ta c th s dng cc my AOI (automated Optical Inspection) quang hc hoc s dng X-ray. Cc thit b ny cho php pht hin cc li v tr, li tip xc ca cc linh kin v kem hn trn b mt ca mch in. Li im khi s dng cng ngh SMT

Linh kin nh hn Cn phi to ra rt t l trong qu trnh ch to PCB Qu trnh lp rp n gin hn Nhng li nh gp phi trong qu trnh ng gi c hiu chnh t ng (sc cng b mt ca kem hn nng chy lm lch v tr ca linh kin ra khi v tr ca chn hn trn bo mch) C th gn linh kin ln trn hai mt ca bo mch Lm gim tr v khng ca lp ch tip xc (lm tng hiu nng ca cc linh kin cao tn)

Tinh nng chu bn b hn trong iu kin b va p v rung lc Gi linh kin cho cng ngh SMT thng r hn gi linh kin cho cng ngh xuyn l Cc hiu ng cao tn (RF) khng mong mun t xy ra hn khi s dng cng ngh SMT so vi cc linh kin cho dng cng ngh hn ch, to iu kin thun li cho vic d on cc c tuyn ca linh kin.

Cng ngh SMT ra i, thay th dn dn cng ngh ng gi xuyn l, iu ny khng c ngha l SMT hon ton l tng. Nhng im cn phi khc phc cng ngh ny l qu trnh cng ngh ch to SMT cng phu hn nhiu so vi vic s dng cng ngh ng gi xuyn l, u t ban u tng i ln v tn thi gian trong vic lp t h thng. Do kch thc linh kin rt nh, phn gii ca cc linh kin trn bo l rt cao nn vic nghin cu, trin khai cng ngh ny mt cch th cng s lm cho t l sai hng tng i ln v tn km. Hin nay cc sn phm SMT tng i a dng p ng cc nhu cu t th cng ti t ng ha hon ton. Hu nh cc hng sn xut thit b SMT hng u th gii u tham gia trin lm ln ny nh Samsung-SMT, Speedline (M) hay Juki (Nht bn). Vi s xut hin ca sn phm SMT, vi xu hng dch chuyn u t, Vit Nam chc chn s tr thnh nhng quc gia c nn cng nghip in t pht trin trong khu vc v trn th gii trong tng lai khng xa. Cng ngh SMT ti Vit nam c t hn chc nm nay, tuy nhin ch yu l cc cng ty FDI mi c tim lc ti chnh mua sm. Cn cc cng ty Vit nam m trn u ngn tay cng ch c vi cng ty s dng cng ngh ny nh ViettronicBinhHoa, Alcatel, Hanel... tuy nhin nng lc sn xut cn rt thp. Ch yu cc cng ty Vit nam ang s dng cng ngh cm l y l cng ngh c v cc sn phm ngy cng b thu hp. Nu ni rng cng nghip in t l nghnh cng nghip mi nhn ca nn kinh t trong tng lai th chuyn thay i cng ngh ca cng ty trong nc phi rt khn trng. Tuy nhin nu u t vo cng ngh sn xut ny th chi ph kh cao, khng c nhiu ngi dm ngh n hu nh tt c cc cng ty u sang Trung Quc nh gia cng thu. Nh vy lm sao m chng ta c th to cng n vic lm v li nhun trong lnh vc ny??? Xin cc bc c kin v vn ny. u l li thot cho nghnh cng nghip in t vit nam.

bi vit ca bn khng chi tit lm.SMT l g? n ng dng vo u..thm ch ci ch SMT l vit tt ch g?? gii thiu khng r lm so bn lun c bn maivinh 23-09-2009, 04:29 PM C th gii thiu mt cch tng qut th ny cho cc bn r: SMT (Surface-mount technology) : cng ngh hn linh kin b mt l phng php gn cc linh kin in t trc tip ln trn b mt ca bo mch (PCB). Cc linh kin in t dnh ring cho cng ngh ny c tn vit tt l SMD (surface-mount devices). Trong cng nghip in t, SMT thay th phn ln cng ngh ng gi linh kin trn tm PCB xuyn l theo linh kin in t c c nh trn b mt PCB bng phng php xuyn l v hn qua cc b ch nng. Cc hng khc nhau s hu nhng b quyt v c quyn cng ngh khc nhau khi ch to cc loi my gn chp trn dy truyn SMT. Tuy vy, nhng cng on t lc np liu cho ti lc thnh phm (bo c gn chp) th tng i ging nhau. Cc cng on bao gm: 1) Qut hp kim hn (kem hn) ln trn bo mch trn vo cc v tr trn c m sn chn hn bng vng, thic-ch, bc 2) Gn chp, gn IC 3) Gia nhit lm mt 4) Kim tra v sa li [Only registered and activated users can see links] Mt s k thut hn chp * K thut hn dng cht keo dnh: k thut ny ngi ta hay s dng cc hp cht c tnh cht bm dnh tt nh polyimide, epoxy hoc keo bc lm vt liu hn khi gn chp ln leadframe. Sau khi xc nh c v tr tng thch gia die v cu hnh trn leadframe, die s c y ra khi bt chn khng, nn ln trn b mt ca epoxy v qu trnh hn kt thc.K thut hn eutectic, thng c ng dng trong ng gi kn, s dng hp kim cng tinh gp die ln trn leadframe. K thut hn tin tin ny da trn vic s dng vt liu hn to ra hp kim cng tinh mt iu nhit c bit no , v im nng chy ca hp kim thng thp hn khi n dng kim loi n l. Hp kim Au-Si, Au-Sn hoc Pd-Si thng c s dng rng ri trong k thut ny. gn c die ln leadframe u tin ngi ta ph mt lp vng vi dy ph hp ln trn b mt leadframe hoc die). * K thut hn dy (wire bonding): Khng ging nh hn dy thic trn cc linh kin in t vy, hn dy chp l mt vic

lm i hi tnh kin nhn v s hiu bit v cu trc IC. Vt liu hn y thng l hp kim Au hoc Al c ng knh mt ct ngang tiu chun c 25 micromt, C hai phng php gn si dy ln nhng mi hn v cng nh b l: phng php hn p nhit (thermocompression bonding - TC) v phng php hn dng diu m (ultrasonic bonding- US). Phng phpTC c pht trin ti phng th nghim Bell (Hoa K) phc v cho ngnh vi in t t 1957, v mi n nhng nm 1960 mi c thay th bng phng php hn dng siu m. Phng php hn TC dng lc nn khi hn, nhit cao trong iu kin chn khng hoc kh tr (N2, hoc Ar) to ra mi hn. * K thut hn dng siu m (Ultrasonic Technique): Mi hn, trong phng php ny, nhn c nh tng tc ca cc yu t: lc chn khng, p sut, nhit v thi gian. S tr gip ca camera v mn hnh to thun li rt nhiu cho ngi k s. Khi hn, dy hn c t ln trn mi hn (bonding pad). Tn s siu m cng, lc nn cng vi s c st im u hn tip xc vi mi hn u tin lm sch im tip xc gia hai vt liu cn hn (ty b lp oxt b mt) sau l lm tng nhit khu vc dn n c s khuch tn vo nhau gia cc vt liu. V d my hn ca cng ty Westbond s dng mt b pht siu m knh i, hot ng tn s 63 KHz c iu khin bi vi x l Motorola 68000, thi gian pht xung v cng sut xung c th thay i mt cch n gin, bin dao ng ch c st (scrubs mode) c vi chc micromet xung quanh v tr cn hn. Trong k thut hn dng siu m, hnh dng mi hn s quy nh cu hnh ca u hn l cc php hn trn (ball bonding mi hn c dng cu) v php hn dt (wedge bonding mt hn c dng dt). Di tc dng ca xung siu m v lc nn, dy hn b nn Dt v dnh vo im hn. Tham kho wikipedia, smtnet v smtvn. Hi vng cc bn c 1 khi nim r rng hn v SMT. Chc vui. tranvinhloc 23-09-2009, 06:06 PM bi vit ca bn khng chi tit lm.SMT l g? n ng dng vo u..thm ch ci ch SMT l vit tt ch g?? gii thiu khng r lm so bn lun c bn Ah, bn hiu lm mnh, mnh cp n gii php no cho cc doanh nghip c th pht trin sn xut bng cng ngh SMT ch mnh khng cp c th SMT l g v hin ti cng ngh SMT hu nh ai lm trong lnh vc in t hiu. Vn l nhu cu ca cc cng ty trong nc hin nay nh th no. Lm sao kch thch doanh nghip u t n. Mong mi ngi bn tho vn ny tranvinhloc

23-09-2009, 06:16 PM C th gii thiu mt cch tng qut th ny cho cc bn r: SMT (Surface-mount technology) : cng ngh hn linh kin b mt l phng php gn cc linh kin in t trc tip ln trn b mt ca bo mch (PCB). Cc linh kin in t dnh ring cho cng ngh ny c tn vit tt l SMD (surface-mount devices). Trong cng nghip in t, SMT thay th phn ln cng ngh ng gi linh kin trn tm PCB xuyn l theo linh kin in t c c nh trn b mt PCB bng phng php xuyn l v hn qua cc b ch nng. Cc hng khc nhau s hu nhng b quyt v c quyn cng ngh khc nhau khi ch to cc loi my gn chp trn dy truyn SMT. Tuy vy, nhng cng on t lc np liu cho ti lc thnh phm (bo c gn chp) th tng i ging nhau. Cc cng on bao gm: 1) Qut hp kim hn (kem hn) ln trn bo mch trn vo cc v tr trn c m sn chn hn bng vng, thic-ch, bc 2) Gn chp, gn IC 3) Gia nhit lm mt 4) Kim tra v sa li [Only registered and activated users can see links] Mt s k thut hn chp * K thut hn dng cht keo dnh: k thut ny ngi ta hay s dng cc hp cht c tnh cht bm dnh tt nh polyimide, epoxy hoc keo bc lm vt liu hn khi gn chp ln leadframe. Sau khi xc nh c v tr tng thch gia die v cu hnh trn leadframe, die s c y ra khi bt chn khng, nn ln trn b mt ca epoxy v qu trnh hn kt thc.K thut hn eutectic, thng c ng dng trong ng gi kn, s dng hp kim cng tinh gp die ln trn leadframe. K thut hn tin tin ny da trn vic s dng vt liu hn to ra hp kim cng tinh mt iu nhit c bit no , v im nng chy ca hp kim thng thp hn khi n dng kim loi n l. Hp kim Au-Si, Au-Sn hoc Pd-Si thng c s dng rng ri trong k thut ny. gn c die ln leadframe u tin ngi ta ph mt lp vng vi dy ph hp ln trn b mt leadframe hoc die). * K thut hn dy (wire bonding): Khng ging nh hn dy thic trn cc linh kin in t vy, hn dy chp l mt vic lm i hi tnh kin nhn v s hiu bit v cu trc IC. Vt liu hn y thng l hp kim Au hoc Al c ng knh mt ct ngang tiu chun c 25 micromt, C hai phng php gn si dy ln nhng mi hn v cng nh b l: phng php hn p

nhit (thermocompression bonding - TC) v phng php hn dng diu m (ultrasonic bonding- US). Phng phpTC c pht trin ti phng th nghim Bell (Hoa K) phc v cho ngnh vi in t t 1957, v mi n nhng nm 1960 mi c thay th bng phng php hn dng siu m. Phng php hn TC dng lc nn khi hn, nhit cao trong iu kin chn khng hoc kh tr (N2, hoc Ar) to ra mi hn. * K thut hn dng siu m (Ultrasonic Technique): Mi hn, trong phng php ny, nhn c nh tng tc ca cc yu t: lc chn khng, p sut, nhit v thi gian. S tr gip ca camera v mn hnh to thun li rt nhiu cho ngi k s. Khi hn, dy hn c t ln trn mi hn (bonding pad). Tn s siu m cng, lc nn cng vi s c st im u hn tip xc vi mi hn u tin lm sch im tip xc gia hai vt liu cn hn (ty b lp oxt b mt) sau l lm tng nhit khu vc dn n c s khuch tn vo nhau gia cc vt liu. V d my hn ca cng ty Westbond s dng mt b pht siu m knh i, hot ng tn s 63 KHz c iu khin bi vi x l Motorola 68000, thi gian pht xung v cng sut xung c th thay i mt cch n gin, bin dao ng ch c st (scrubs mode) c vi chc micromet xung quanh v tr cn hn. Trong k thut hn dng siu m, hnh dng mi hn s quy nh cu hnh ca u hn l cc php hn trn (ball bonding mi hn c dng cu) v php hn dt (wedge bonding mt hn c dng dt). Di tc dng ca xung siu m v lc nn, dy hn b nn Dt v dnh vo im hn. Tham kho wikipedia, smtnet v smtvn. Hi vng cc bn c 1 khi nim r rng hn v SMT. Chc vui. Cm n phn post ca bn nu bn cp n cng ngh SMT th phn u l Ok, phn th 2 l cng ngh ch chp khng lin quan g n SMT. Rt c th khi bn post phn 2 nhiu ngi s hiu l cc giai on trong qu trnh gn linh kin ln bo mch s dng trong cng ngh SMT.