cng Cng Ngh Vi in T
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T.
CNG N TP CNG NGH VI IN T 1. So snh v phn tch c im cc cng ngh mch
tch hp? Cc loi cng ngh mch tch hp: SSI (small scale intergration):
Tch hp qui m nh. MSI (Medium scale intergration): Tch hp qui m
trung bnh. LSI (Large scale integration): Tch hp theo qui m ln.
VLSI (Very large scale intergration): Tch hp theo quy m rt ln. ULSI
(Ultra large scale integration): Tch hp qui m khng l. c im ca cc
cng ngh mch tch hp : Cng ngh SSI Tch hp qui m nh. S bng bn dn tch
hp bn trong IC thp, khong 1-12 bng bn dn. Bao gm cc cng logic c bn
(or, and..) MSI Tch hp qui m trung bnh, s bng bn dn tch hp bn trong
100 n 1000. LSI Tch hp quy m ln, s lng transitor tch hp bn trong t
1000 n 20000. VLSI Tch hp trn qui m rt ln, s lng transitor tch hp
bn trong khong 20000 n 500000. Mi th u c tch hp trn mt chip. ULSI
Tch hp trn qui m rt ln, s lng transitor tch hp bn trong ln n hng
triu. c ch to trn cng ngh nanomet, hiu nng x l cao v phc tp. S dng
trong cc my tnh ngy nay, c b x l 64 bit, dng x l nh, m thanh chuyn
dng, thi gian
c im
Ch yu c p dung cho cc mch in t c bn, cc my tnh cm tay n gin. ng
dng
Bao gm nhiu cng logic bn trong, thc hin chc nng cao hn nh mch m
v cc chc nng logic tng
Tch hp nhiu tnh nng logic hn thm ch m nhim chc nng ca mt chip x
l. Vd nh MCU, chip iu
S dng nh mt chip x l hon chnh, c b x l 16bit 32 bit. c ng dng lm
b x l trung tm, iu
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cng Cng Ngh Vi in T
khin LCD, khin cc thc. ROM,RAM,.. mch chuyn dng 2. Phn loi cc
loi mch tch hp v nh lut Mooore ? Phn loi mch tch hp da vo qui trnh
sn xut v phn loi theo mt . Mt . o SSI (small scale intergration):
Tch hp qui m nh. o MSI (Medium scale intergration): Tch hp qui m
trung bnh. o LSI (Large scale integration): Tch hp theo qui m ln. o
VLSI (Very large scale intergration): Tch hp theo quy m rt ln. o
ULSI (Ultra large scale integration): Tch hp qui m khng l. Qui trnh
sn xut, c th chia IC ra lm 3 loi: IC mng (film IC): Trn mt bng cht
cch in, dng cc lp mng to nn cc thnh phn khc.Loi ny ch gm cc thnh
phn th ng nh in tr, t in, v cun cm. Dy ni gia cc b phn: Dng mng kim
loi c in tr sut nh nh Au, Al,Cu... in tr: Dng mng kim loi hoc hp
kim c in tr sut ln nh Ni-Cr; Ni-Cr-Al; CrSi; Cr c th to nn in tr c
tr s rt ln. T in: Dng mng kim loi ng vai tr bn cc v dng mng in mi
SiO; SiO2 , Al2O3 ; Ta2O5 . Tuy nhin kh to c t c in dung ln hn
F/cm2.0,02. Cun cm: dng mt mng kim loi hnh xon. Tuy nhin kh to H vi
kch thc hp l. Trong s IC, ngi ta trnh c cun cm ln qu 5 dng cun cm
khng chim th tch. Cch in gia cc b phn: Dng SiO; SiO2 ; Al2O3 . IC n
tnh th. Cn gi l IC bn dn (Semiconductor IC) l IC dng mt (Subtrate)
bng cht bn dn (thng l Si). Trn (hay trong) , ngi ta ch to
transistor, diode, in tr, t in. Ri dng cht cch in SiO 2 ph ln che
ch cho cc b phn trn lp SiO 2 , dng mng kim loi ni cc b phn vi nhau.
Transistor, diode u l cc b phn bn dn. in tr: c ch to bng cch li dng
in tr ca lp bn dn c khuch tn tp cht. T in: c ch to bng cch li dng
in dung ca vng him ti mt ni P-N b phn cc nghch. i khi ngi ta c th
thm nhng thnh phn khc hn ca cc thnh phn k trn dng cho cc mc ch c
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cng Cng Ngh Vi in T
Cc thnh phn trn c ch to thnh mt s rt nhiu trn cng mt chip. C rt
nhiu mi ni gia chng v chng c cch ly ) nh nhng ni P-N b phn cc nghch
(in tr c hng trm M). IC lai. L loi IC lai gia hai loi trn. T vi mch
mng mng (ch cha cc thnh phn th ng), ngi ta gn ngay trn ca n nhng
thnh phn tch cc (transistor, diode) ti nhng ni dnh sn. Cc
transistor v diode gn trong mch lai khng cn c v hay ring, m ch cn c
bo v bng mt lp men trng. u im ca mch lai l: C th to nhiu IC
(Digital hay Analog). C kh nng to ra cc phn t th ng c cc gi tr khc
nhau vi sai s nh. C kh nng t trn mt , cc phn t mng mng, cc
transistor, diode v ngay c cc loi IC bn dn. 3. Nu c im (cu trc tinh
th, gin nng lng) ca vt liu bn dn? Cht bn dn (Semiconductor) l vt
liu trung gian gia cht dn in v cht cch in. Cht bn dn hot ng nh mt
cht cch in nhit thp v c tnh dn in nhit phng. Cu trc tinh th. Cu trc
tinh th cht bn dn c ba cu trc tinh th, l: cu trc lp phng n, lp phng
tm khi v lp phng tm mt. Silic l mt vt liu bn dn ph bin nht l nguyn
t nhm IV v c cu trc kim cng. Germany cng l mt nguyn t nhm IV v c cu
trc ging kim cng. Mi nguyn t trong cu trc t din c 4 nguyn t ln cn
gn nht v cu trc ny l thnh phn c bn ca mng kim cng.
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Gin nng lng. Tnh cht dn in ca cc vt liu rn c gii thch nh l thuyt
vng nng lng, c ba vng nng lng chnh: Vng ha tr (Valence band): L vng
c nng lng thp nht theo thang nng lng, l vng m in t b lin kt mnh vi
nguyn t v khng linh ng. Vng dn (Conduction band): Vng c mc nng lng
cao nht, l vng m in t s linh ng (nh cc in t t do) v in t vng ny s l
in t dn, c ngha l cht s c kh nng dn in khi c in t tn ti trn vng dn.
Tnh dn in tng khi mt in t trn vng dn tng. Vng cm (Forbidden band):
L vng nm gia vng ha tr v vng dn, khng c mc nng lng no do in t khng
th tn ti trn vng cm. Nu bn dn pha tp, c th xut hin cc mc nng lng
trong vng cm (mc pha tp). Khong cch gia y vng dn v nh vng ha tr gi
l rng vng cm, hay nng lng vng cm (Band Gap).
Gin nng lng ca cht bn dn
Nh vy, tnh dn in ca cc cht rn v tnh cht ca cht bn dn c th l gii
mt cch n gin nh l thuyt vng nng lng nh sau:
Kim loi c vng dn v vng ha tr ph ln nhau (khng c vng cm) do lun
lun c in t trn vng dn v th m kim loi lun lun dn in. Cc cht bn dn c
vng cm c mt rng xc nh. khng tuyt i (0 K), mc Fermi nm gia vng cm, c
ngha l tt c cc in t tn ti vng ha tr, do cht bn dn khng dn in. Khi
tng dn nhit , cc in t s nhn c nng lng nhit ( vi l hng s Boltzmann)
nhng nng lng ny cha in t vt qua vng cm nn in t vn vng ha tr. Khi
tng nhit n mc cao, s c mt s in t nhn c nng lng ln hn nng lng vng cm
v n s nhy ln vng dn
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v cht rn tr thnh dn in. Khi nhit cng tng ln, mt in t trn vng dn
s cng tng ln, do , tnh dn in ca cht bn dn tng dn theo nhit (hay in
tr sut gim dn theo nhit ). 4. Cu trc ca transitor tng cng (nmos v
pmos) v cc tnh cht, tham s c bn ca n? Transitor NMOS: Cu trc:
Cu trc gm nn (Substrate) Silic loi p, hai vng khuch tn loi (n+)
gi l ngun (Source) v mng (Drain). Gia ngun v mng l mt vng hp nn p
gi l knh, c ph mt lp cch in (SiO2 ) gi l cng oxide. Transitor PMOS
: Cu trc :
Cu trc gm nn (Substrate) Silic loi n, hai vng khuch tn loi (p+)
gi l ngun (Source) v mng (Drain). Gia ngun v mng l mt vng hp nn n
gi l knh, c ph mt lp cch in (SiO 2 ) gi l cng oxit.
Tnh cht v cc tham s c bn : Transitor hot ng nh cng tc, hot ng
hai trng thi, ng hoc [email protected]
cng Cng Ngh Vi in T
- Khi dn, ty theo nng pha ca cht bn dn m transistor c ni tr rt
nh (t vi chc n hng trm K tng ng vi mt kha ng. - Khi ngng,
transistor c ni tr rt ln (hng 1010 ) , tng ng vi mt kha h. Mc logic
ca transitor tng cng:
Th ngng. c tuyn.
5. Gii thiu, phn tch cc cng ngh chnh trong cng ngh ch to vi mch?
Cc cng ngh ch to vi mch Em khng hiu r cu hi lm, c phi l cc k thut s
dng cht to t wafer n chip thnh phm? Nh vy th c 5 k thut: X l b mt.
Oxy ha. Khuch tn. Quang khc. n mn.
6. Sn xut wafer? (phn loi c tnh, nui cy tinh th, phng php ch to)
Tm tt qu trnh sn xut wafer. - Ct t nhin >> thi sillic hnh tr
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cng Cng Ngh Vi in T
Sillic, nguyn t ha hc ph bin th hai trn tri t sau oxy, c s dng
nhiu v n l cht bn dn t nhin. Quy trnh sn xut sillic t ct t nhin: Ct
(sillic) => l h quang => sillic sch (MGS_metallurgical grade
sillicon) => l phn ng lng vi kh HCl => kh silane v
chlosilance => tch kh lm sch v chng ct => to ra sillic sch cp
in t (EGS_electronic grade sillicon). C hai phng php to ra Si sch.
Phng php 1: Ph Si t kh cha Si ln mt ng Si nng. ng Si ln ln rt nhanh
n ng knh 20cm. C phn ng ha hc sau: SiHCl3 (kh) + H2 = Si (tinh th)
+ 3HCl (kh) Tuy nhin phng php ny t c s dng. Phng php 2: Kh cha Si v
ht mm tinh khit c nui trong b lng. Si sch mc in t (EGS) c cu trc a
tinh th c tp cht khong 20ppm. Sau Si_EGS c cho nng chy v nui thnh
thi n tinh th. C 3 phng php nui t Si_EGS: o Pp czchraiski: mt ht
tinh th mm c nhng trong Si EGS nng chy v tinh th mm s c ko gradual
sao cho thi n tinh th c ng knh 15cm trong qu trnh lm ngui. o Pp nng
chy vng: Mt thi Si c t theo phng thng ng c lm nng chy cc b t di ln.
Vng nng chy c ti tinh th ha nh cc tinh th mm. o Pp Bridgeman: Dng
ch yu cho GaAs, trong vt liu a tinh th c lm nng chy dc theo thuyn
hp v nh l qut dc v c l ngui t mt pha c gn vi tinh th. - Cc c trng
ca phin wafer: Mi vt nh du nh hng tinh th. Vt ln nht l vt chnh vung
gc vi hng .
Sau khi mi vt thi c nhng vo dung dch n mn ty b sai hng do mi c
kh dy ra. Thng dng HF-HNO3. Tip theo, ca thi thnh tng
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7. Phng php quang khc v phng php n mn trong cng ngh ch to vi
mch? Quang khc: Khi nim. Quang khc (photolithography) l k thut s
dng trong cng ngh ch to bn dn v vi in t, nhm to ra cc chi tit ca vt
liu v linh kin vi hnh dng v kch thc xc nh bng cch s dng cc bc x nh
sng lm bin i cc cht cn quang trn b mt to ra hnh trn b mt silic.
Phng php ny c s dng ph bin trong cng nghip bn dn vi in t nhng khng
cho php to ra cc chi tit nh do tnh hn ch ca nhiu x nh sng nn cn gi
l quang khc micro. Nguyn l h quang khc. Mt h quang khc bao gm mt
ngun pht tia t ngoi, chm tia t ngoi ny c khuch i ri sau chiu qua mt
mt n (photomask). Mt n l mt tm chn sng c in trn cc chi tit cn to
(che sng) che khng cho nh sng chiu vo vng cm quang, to ra hnh nh ca
chi tit cn to trn cm quang bin i. Sau khi chiu qua mt n, bng ca chm
sng s c hnh dng ca chi tit cn to, sau n c hi t trn b mt phin ph cm
quang nh mt h thu knh hi t
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ng dng ca k thut quang khc: Quang khc l k thut c pht trin t u th
k 20, v c s dng rng ri nht trong cng nghip bn dn ch to cc vi mch in
t trn cc phin Si. Ngoi ra, quang khc c s dng trong ngnh khoa hc v
cng ngh vt liu ch to cc chi tit vt liu nh, ch to cc linh kin vi c
in t (MEMS) n mn: Trong k thut n mn (etching ), cn quang s c tc dng
bo v phn vt liu mun to hnh. Ngi ta ph vt liu cn to ln , sau ph cht
cn quang ri em chiu in t. Cn quang s dng l cn quang m, tc l thay i
tnh cht sao cho khng b ra tri sau khi qua dung dch trng ra, c tc
dng bo v phn vt liu bn di. Sau c mu s c a vo bung n mn, phn vt liu
khng c cn quang s b n mn v gi li phn c bo v, c hnh dng ca cn quang.
Cui cng l ra cn quang bng dung mi hu c. Cc k thut n mn thng dng l n
mn kh (dry etching), s dng cc plasma hoc hn hp kh c tnh ph hy mnh
(CH 4/O2/H2, F2...); hay n mn ha t (dng cc dung dch ha cht ha tan
vt liu 8. Oxi ha nhit v phng php pha tp trong cng ngh ch to vi mch?
Oxy ha nhit: Nhm to ra mt lp oxide SiO2 c cc c tnh sau: To ra mt lp
ph bn, chc trn b mt tinh th sillic c h s gin n gn bng h s gin n ca
sillic. C kh nng bo v sillic trong khi khuych tn cc tp
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Bo v b mt cc linh kin bn dn di tc dng ca mi trng b ngoi. Ngoi ra
lp SiO2 cn c dng lm cc (gate) ca cho bng bn dn (transitor) C nhiu
phng php tao ra lp SiO2 nhng phng php c s dng rng ri nht nhn lp
SiO2 l phng php oxy ha nhit cao (100000C 110000C). Trong qu trinh
ch to mch tch hp ngi ta thng phi dng lp SiO2 trn b mt tinh th Si.
Pha tp: c hai phng php, l khuch tn v cy ion. Khuch tn: Khuch tn l
mt qu trnh m qua nhng loi nguyn t tp cht c bit c th c a vo trong vt
liu silic. Qu trnh pha tp ny lm thay i tnh cht in ca silic v hnh
thnh nn tip xc pn. (Tip xc pn l thnh phn c bn ca thit b bn dn.)
Ming silic b oxi ha hnh thnh ioxit silic v nhng ca s nh c m trong
oxit trong nhng vng c chn la dng k thut quang khc v n mn nh va c m
t trn. Cy ion: y l qu trnh thay th cho qu trnh khuch tn nhit cao.
Mt chm nhng ion pha tp c gia tc nng lng cao v n b mt bn dn. Khi
nhng ion i vo silic, chng va chm vi nhng nguyn t silic, nh mt nng
lng v cui cng dng li ti mt su no trong tinh th. Bi v qu trnh va chm
v bn cht l thng k, do c mt s phn b su thm nhp ca nhng ion pha tp. u
im: (1) qu trnh cy ion l mt qu trnh nhit thp, (2) nhng lp tp cht c
c nh rt tt. Lp cn quang v lp oxit c th c dng ngn cn s thm nhp ca
nhng nguyn t tp cht cho qu trnh cy Ion c th xut hin trong nhng vng
rt c chn la ca silic. Nhc im l tinh th silic c th b hng bi s thm
nhp ca nhng nguyn t tp cht dn n s va chm ca nhng nguyn t tp cht ti
v nhng nguyn t silic ch. Tuy nhin, a s s h hng c th c loi b bng cch
luyn silic nhit cao. Nhit luyn thng rt thp hn nhit ca qu trnh khuch
tn. 9. Cng ngh Cmos v cng ngh ch to Cmos? - CMOS, vit tt ca
"Complementary Metal-Oxide-Semiconductor" trong ting Anh, l thut ng
ch mt loi cng ngh dng ch to vi mch tch hp. Cng ngh CMOS c dng ch to
vi x l, vi iu khin, RAM tnh v cc mch lgc s khc. Cng ngh CMOS cng c
dng rt nhiu trong cc mch tng t nh cm bin hnh nh, chuyn i kiu d liu,
v cc vi mch thu pht c mt tch hp cao trong lnh vc thng tin. - Ch to
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cng Cng Ngh Vi in T
Cc transitor CMOS c ch to trn mt mu sillicon. Qu trnh tch hp
ging nh qu trnh in khc. mi bc, cc vt liu khc nhau s c chn vo hoc ct
b ra. Quy trnh ch to: Bt u vi mt ming bn dn th Ch to cng o t phn y
ln Bc u tin l to ra mt lp bn dn giu n. + Ph ln ming bn dn mt lp
SiO2 (oxide) + B i lp oxide ni cn to bn dn giu n. + a trc tip hoc
khuch tn cht kch tp loi n vo lp bn dn l ra. + Ph SiO2 (1) Qu trnh
oxi ha. To lp SiO2 trn b mt ming bn dn Si, trong nhit 900oC n
1200oC vi H2O hoc O2 trong l oxi ha.
(2) Ph mt lp quang tr. Quang tr l mt polimer nhy sng v mm i khi
phi ra nh sng. (3) In khc. M lp quang tr v tr ca mt n n-well. Ct b
lp quang tr v tr ny.
Khc: Khc oxide bng hydroflouric acid (HF) Ch khc lp oxide khi lp
quang tr l ra. (4) Ct b quang tr. Ct b lp quang tr cn li Dng hn hp
acid gi l phng php piranah, bc ny cn thit lp quang tr khng b chy
trong bc tip theo. (5) Khuch tn n-well. n-well to bi s khuch tn hay
tim ion Khuch tn: + t ming bn dn trong l gas arsen. + Nung n khi cc
nguyn t As khuch tn vo Si. Tim ion:[email protected]
cng Cng Ngh Vi in T
+ Thi vi bn dn cc chm ion As. + Cc ion b chn bi SiO2, ch i vo
nhng ch Si b l ra. (6) Ct b lp oxide Ct b lp oxide cn li, dng acid
HF Tr li ming bn dn gc vi mt lp n-well, cc bc tip theo cng gm mt
chui cc bc tng t nh cc bc trn. (7) Ph lp sillicon a tinh th. Trm mt
lp rt mng gate oxide
