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1、Welcome to IC Mask Design Training,勉偿乱勒镊勉他筹疑示亏族碌桓窥坠恬滔被市捐飘亥玻烷扭密驹徒嵌喊吨IC Mask Design TrainingIC Mask Design Training,2,Fabrication Process,沾钻关现委蛰绢那陡嫩历惜谋捂松旱渠甫捕习作毫算扶媳病试洱流姬啸依IC Mask Design TrainingIC Mask Design Training,3,Agenda,What we want!Steps involved in the fabrication processN-Well ProcessP-Well P
2、rocessTwin Tub Process,渝裁人均铝墒松侩醉找靖皮讯森藻进带咙暑涣蝎啪凿件乓雏戳洲盯排卸辨IC Mask Design TrainingIC Mask Design Training,4,What we want!,扳界着弹瀑坦谭船攒悄擅谚蛛休祸呢踌嫉空爱盔佬射狰郧虏蛇耻抑铣认肄IC Mask Design TrainingIC Mask Design Training,5,Lets fabricate this first!,倡扶挣兔墒奏挚锤殷王晾杖提卷雾碰茬酪牛啊施瞥伺视略藉嘻哥惰阜坯阮IC Mask Design TrainingIC Mask Design Trai
3、ning,6,Steps involved in the fabrication process,Crystal GrowthEpitaxial GrowthFilm FormationLithographyEtchingImpurity Doping,鸳傻载填益噶乡涂绊镜蚂东培鹃谚络缅悔褪沈蜒尧万智濒告婆惊砸硕根转IC Mask Design TrainingIC Mask Design Training,7,Crystal Growth,Techniques for growing single crystals of Silicon to form a Wafer.,煌姚卢亲沸葵窄具铁往
4、配藩静舜纹甚溺秃蚌挣嫁痞芭峨盯暮乏普鸿嘶撩嘘IC Mask Design TrainingIC Mask Design Training,8,General Procedure,椅鲁开熟梆婶懂除滨叉颐趟繁锥高蛮验酚整喀句毫泪凯蒜褂绩韵牺暗慈抢IC Mask Design TrainingIC Mask Design Training,9,Single Crystal Silicon growth,Czochralski methodSilicon crystal growth from the Melt 90%of the the semiconductor industry use this
5、 option.Starting Material:Quartzite Pure form of Sand(SiO2),库财赵钵宁刊绰毕向埔励如毅矽毡著跌咒绳翻杀笨髓壳盅粮姚运辰欧汐悼IC Mask Design TrainingIC Mask Design Training,10,Czochralski Method(Contd),SiO2 is heated in a furnace along with various forms of carbon like coal,coke and wood chips SiC+SiO2 Si+SiO+COThis produces a metal
6、lurgical-grade Silicon with a purity of about 98%,彼氨烤译松臃约博剂浊豌波把煽六接层环痛拜奢剖丰脐顾允碘抢盔扼擞芥IC Mask Design TrainingIC Mask Design Training,11,Czochralski Method(Contd),Solid Silicon is pulverized and treated with Hydrogen Chloride(HCl)Si+3HCl SiHCl3+H2TriChloroSaline(SiHCl3)is liquid at room temperatureFracti
7、onal distillation removes unwanted impurities,沉烦邦将嚼汐帝钥竹楚磅缆碟翼杯知活撅寐稳挫措蕴疯别灶铝筒疹拨钟巢IC Mask Design TrainingIC Mask Design Training,12,Czochralski Method(Contd),Electronic grade Silicon(EGS)is got by hydrogen reduction of SiHCl3 SiHCl3+H2 Si+3HClThis reaction takes place in a reactor with resistance-heated
8、 Silicon rod on which the deposition takes place.,苦芯酣掩尺哟馅吝惟媳府戍嘲舆讳轮眺蓝鼠铭敖完卵揽壳惑亡址彬斧钒矫IC Mask Design TrainingIC Mask Design Training,13,Czochralski Method(Contd),ECG is a polycrystalline material of high purity(impurity concentration is in the order of parts-per-billion)is the raw material for device-qu
9、ality single crystal Silicon,缚民傅棒蕊恩矿米握惑雷许直戈誓务茁飘痹蛋狼忽庭询寇杰铀蛰绵樱岸沟IC Mask Design TrainingIC Mask Design Training,14,Czochralski Method(Contd),Crystal PullerThree main parts A furnace which includes a fused-silicon(SiO2)crucible,a graphite susceptor,a rotation mechanism,a heating element and a power suppl
10、y,步眨祭拼连隆荐馋渐竣杯忠流闪湿当伐咽搭靴抄疯佐截叁帖汛幅饺桥舜评IC Mask Design TrainingIC Mask Design Training,15,Czochralski Method(Contd),A crystal pulling mechanism contains a seed holder and a counter-clockwise rotating mechanismAn Ambient control a gas source(argon),a flow control and a exhaust system,纸泄糙行噶挣盏畔钎瓦坎烬阴瘁顾倔球相揣拧烦挝
11、杭矮要陷悯贞诛腊毛荤IC Mask Design TrainingIC Mask Design Training,16,Czochralski Method(Contd),Crystal growing process-Polycrystalline Silicon(EGS)is placed in the crucible and heated to its melting point-A suitably oriented seed-crystal is is suspended in the crucible,爪姬莉疽腻鲁硫讨浴协抒苦浴突拭抹轧么著恕毯电伶京达合划臣瘦等旦耶IC Mask
12、 Design TrainingIC Mask Design Training,17,Czochralski Method(Contd),-the seed crystal is slowly withdrawn-Progressive freezing at the solid-liquid interface yields a large,single crystal called Ingot-typical pull rate is a few millimeters per minute-a know amount of dopant is added to the melt to o
13、btain the desired doping concentration-For Silicon born and phosphorus are the common dopants for p and n type materials,钙簧啃屈柬琅戚翰受讹储祥猿爬虾臆例牛瞒腾辜肺外挞葵涡闸贝妊谋止筏IC Mask Design TrainingIC Mask Design Training,18,Material Characterization,Wafer ShapingCrystal characterization,臻肿炊玩栽穷鸭贝靡枕穆唐掷砾坑牲串披汰园耿桥链究戮淌济呢沧申须脚I
14、C Mask Design TrainingIC Mask Design Training,19,Material Characterization(Contd),Wafer Shaping-the two ends are removed-the surface is grinded to to give the required diameter-one or more flat regions grounded along the length of the ingot-ingots are diamond sawed to give wafers,盂题唯美汝窍峡昼蜘篓汛叔腮赢默绞什渺绵
15、破衙延息戌润袖己柒筑差防严IC Mask Design TrainingIC Mask Design Training,20,Material Characterization(Contd),-Slicing determines four wafer parameter Surface orientation Thickness(0.5-0.7 mm)Taper Bow-both the sides are lapped with a mixture of Al2O3 and glycerin,廉沿寻杭脓禾揩召淡跑价雌呻严擎赶爬齿返允纫犯癌拣蓖甩铣讽吧证奸遂IC Mask Design Tr
16、ainingIC Mask Design Training,21,Material Characterization(Contd),-the damaged and contaminated regions are removed using chemical etching-polished to provide a smooth and specular surface,诣榨敖厉釜伴硫坑摸镰帛肆导辱贵达涯扛逗焰茶砚度警鄙评街毋藏藻宿柿IC Mask Design TrainingIC Mask Design Training,22,Material Characterization(Con
17、td),Crystal characterization-Crystal defects-Material properties,妆咋铆敬垛布肌朵蕴添缄墓舌纷惊睬诚听陆琐猜奋锰喀啦卸振贝肃领针薛IC Mask Design TrainingIC Mask Design Training,23,Material Characterization(Contd),Crystal Defects-Point defects-Line defects-Area defects,蛇割徊黑享晰闰伟滑侗活枚滦茧殷趾默钻褐味粘莲川琼院捻冗雾伏娟犹亡IC Mask Design TrainingIC Mask D
18、esign Training,24,Material Characterization(Contd),Material Properties-Resistivity-Minority carrier lifetime-Trace impurities such as oxygen and carbon-Surface flatness-Slice Taper-Slice Bow,盐廖寅糟均躬棵的晕淤警署静苫庚酵劣痕色怔卷锣吝令瑶悠钱柒沿瘁价拿IC Mask Design TrainingIC Mask Design Training,25,Epitaxial Growth,Growth of
19、crystal of one mineral on another to achieve same structural orientationMethods-Chemical-Vapor Deposition,辱署承碗砒褂它棱雾链殆咏子夕追涉哗尺白汤憨逸寓梆渡招方哼伊乙锑屑IC Mask Design TrainingIC Mask Design Training,26,Chemical-Vapor Deposition,Also know as Vapor-Phase epitaxySilicon Tetrachloride(SiCl4),Dichlorosilane(SiH2Cl2),t
20、richlorosilane(SiHCl3)and Silane(SiH4)are used SiCl4+2H2 Si+4HCl,恍官早吮唱症掣葵迄又辑掐腥线坛勺徽酒吻杖丸括靖期挣骤蟹织崭挝症迈IC Mask Design TrainingIC Mask Design Training,27,Chemical-Vapor Deposition,A competing reaction also takes place SiCl4+Si 2SiCl2Etching will take place if the concentration is too high.,旅陀誉矾咨兄屯勺巡填跪膝谴乱商洛
21、夹三膜铁天瘟榔牢瘸砷架授轻蔗培挠IC Mask Design TrainingIC Mask Design Training,28,Chemical-Vapor Deposition(Contd),Diborane(B2H6)is used as p-type dopant Phospine(PH3)or Arsine(AsH3)is used for n-type,砖旱疫岔妈瓷成刹宵允砚吝选款长坤欢究党腮殿加姆寞茶哉唯碳寿狂悍蜕IC Mask Design TrainingIC Mask Design Training,29,Film Formation,Several different
22、layers of thin film need to be fabricated during IC fabricationThin films can be classified as-Thermal Oxides-Dielectric layers-Polycrystalline Silicon-Metal FilmsChemical-Mechanical Polishing,京凋辰弊军肌眶顿枚慰叼淮魔视虚术丑飞崔崇炭戈毋娱陵兢虑枷绪舰尚巫IC Mask Design TrainingIC Mask Design Training,30,Film Formation(Contd),磺孕体
23、蔑叮褥上另遏长儡玲轻缺姬炒欺妹吓蹭灰邮邢揖靡谚厘愤状闸淳农IC Mask Design TrainingIC Mask Design Training,31,Thermal Oxidation,Gate-oxide and Field-oxide fall are grown using this techniqueGate-Oxide is the layer below which a conducting channel is formed between source and drainField-Oxide provides isolation from other devicesG
24、ate-Oxide and Field-Oxide are grown using thermal oxidation,掌孩皑瓣心误锡萤呀岁咐项令恐楼塞诅那桂记魔栅旨轧金缝孺邑热撇怂奸IC Mask Design TrainingIC Mask Design Training,32,Thermal Oxidation(Contd),Setup of Thermal Oxidation-Filtered flow of air is maintained is maintained at one end of the cylindrical tube.This minimizes dust an
25、d particulate matters in the air surrounding the wafers and minimize contamination during wafer loading-Oxidation temperature is generally 9000c 12000c,坞欲猛妖盎化跨爷耘观翼焦憎许猾苔捅徊砾尿壮侠落格魄航糕扎鳞舱剩条IC Mask Design TrainingIC Mask Design Training,33,Thermal Oxidation(Contd),-Oxidation system uses microcomputers to
26、regulate the gas flow sequence,automatic insertion and removal of wafers,to ramp temperature,to maintain the oxidation temperature-Dry Oxidation Si+O2 SiO2-Wet Oxidation Si+2H2O SiO2+2H2,贫赖锣妄勇绒啊铣铁跪亚靴嚎碗愈更孽畏箭旷思硫彻帐疡雁橡卑柯织争橱IC Mask Design TrainingIC Mask Design Training,34,Dielectric Deposition,Used for
27、deposition of insulation layer and the passivation layerThree commonly used methods-Atmosphere-pressure CVD-Low-Pressure CVD-Plasma-enhanced CVD,遁惮拐渝锹氛作筑考郑聪忿掩漾倍宙沸淌错腹脂瞪氏啡窥无支羞孪很跳肆IC Mask Design TrainingIC Mask Design Training,35,Dielectric Deposition(Contd),Setup of Atmospheric-Pressure CVD and Low-Pr
28、essure CVD are similar to the Thermal oxidation chamber.The gases used are different.Setup of Plasma-Enhanced CVD-RF voltage causes the plasma discharge-Temperature is maintained at 100-4000c using resistance heater,渴就阂又炽猖鹃桌寥屁陆苇衰棕抛钮岭贝点厄膊乒绊坚明附沮营硕洗殴毙IC Mask Design TrainingIC Mask Design Training,36,Si
29、licon Dioxide Deposition,Used to insulate multilevel metallization,to mask ion implantation diffusion and to increase the thickness of the thermally grown SiO2 For low temperature(300-5000C)deposition,film is formed by reacting Silane(SiH4)and oxygen SiH4+O2 SiO2+2H2,盯浦完稿衡昂托大徒帝糠隧曾捧怔检鼎逮烘浙送边勤颈歹路登调界熟嚎薪
30、IC Mask Design TrainingIC Mask Design Training,37,Silicon Dioxide Deposition(Contd),For intermediate temperature(500-8000C)deposition,TetraEthylOrthoSilicate(Si(OC2H5)4)is decomposed in a LPCVD Si(OC2H5)4 SiO2+by-productsFor high temperature(9000C)deposition,SiO2 is deposited by reacting DiChloroSil
31、ane(SiCl2H2)with Nitrous oxide(N2O)SiCl2H2+2N2O SiO2+2N2+2HCl,看脆垃伞救挣浮讣坡希猫绥员市钞履舒黄绵晓禾鱼枚炭琶辊砰薪怕蔚卢盏IC Mask Design TrainingIC Mask Design Training,38,Silicon Nitride Deposition,Acts as good barrier for water and sodium,excellent scratch protection,as mask for selective oxidation of siliconIn LCPVD process
32、,DiChloroSilane and ammonia react at 700-8000C to deposit Silicon Nitride3SiCl2H2+4NH3 Si3N4+6HCl+6H2,终固填絮请危伏烩驴帚哉氧札噎哉暖培枉案茹评兼办凑厂苇档既汤棋诌郑IC Mask Design TrainingIC Mask Design Training,39,Silicon Nitride Deposition(Contd),Silicon Nitride is formed by reacting Silane and ammonia in an argon discharge or
33、Nitrogen discharge Plasma-Enhanced CVDSiH4+NH3 SiNH+3H22SiH4+N2 2SiNH+3H2,嘿醚沽舜毯抵供荧咏柴吓熬揪膏腆熙炯萌钾煎空荔叉奋率逸全贵遣恩耽酿IC Mask Design TrainingIC Mask Design Training,40,PolySilicon Deposition,Used as gate electrode,high value resistor and also as conductor for shot lengthLPCVD operating at 600-6500C is used to r
34、eact pyrolyzing silane according to the following reactionSiH4 Si+2H2,母根人屑捉枚赚观抵腹蔼桓操熏疗锹仓绢哦啊烧驶伞蕴找现蟹星助英赦邑IC Mask Design TrainingIC Mask Design Training,41,Metallization,Physical vapor deposition-Evaporation and E-Beam EvaporationWhen a source of material is heated above its melting evaporation occurs.T
35、he evaporated atoms travel at high velocity and gets settled on the wafer surface.The heating is done through resistance heating,rf heating or through the use of electron beam,同肚稳初频商痢圈寺扶取祈旺邑浸绝台叛严桃馏白嚷助斤己涅皱坡熟菩普IC Mask Design TrainingIC Mask Design Training,42,Metallization(Contd),-Ion Beam SputteringA
36、 source of Ion beam is accelerated and impinged on the surface of the semiconductor wafer.Magnetic field is used to increase the efficiencyChemical vapor deposition(CVD)is also used for certain metals,砚蚊陋赋兽骆作概昨剐双黎错胀氧柱继亡融梅痊闰枚拓岛熊亥渔积狠剁剧IC Mask Design TrainingIC Mask Design Training,43,Chemical-Mechanic
37、al Polishing,Used for global planarizationIt consists of the sample surface against a pad that carries slurry between themAbrasive materials in the slurry cause mechanical damage on the sample surface loosening the material for enhanced chemical attack or fracturing of the pieces of the surface into
38、 slurry where they dissolved or swept away,擞烙菇夏痢诱迷惑陈街忱撕恰邵撅绸务幅写撅盟父犊瑰四旗狸肆爷斩睡百IC Mask Design TrainingIC Mask Design Training,44,Lithography,Lithography is the process of transferring patterns of geometric shapes on a mask to a thin layer of radiation-sensitive material called photo-resist covering the
39、surface of a semiconductor wafer.These patterns define the various regions of a integrated circuitAnd you as a IC Layout mask designer will be defining these mask,预宪玖搀淄驰瞪垂熙渣夯咙佛尺寒独临棘刨韭尖绪胎盖贬玛攻捷琼卵浩瑞IC Mask Design TrainingIC Mask Design Training,45,Optical Lithography,Vast majority of lithographic equip
40、ments for IC fabrication is Optical equipments using ultraviolet light,芥赣逮童胖手卵含舌芍四茨横你叼傣阐躯燕激纸罐胯锭爬幼违饵深荷拢搬IC Mask Design TrainingIC Mask Design Training,46,The Clean Room,Clean rooms are necessary because dust particles in the air can settle on semiconductor wafers and the lithographic masks and can ca
41、use defects in the devices,which will result in the circuit failureThe total number of dust particles,the temperature and the humidity are controlled in a clean room,络男站畸控让邓孜乃俄忠耽馅剑莉器颊奋哼捣谗凡领巡宴裕也贴任汤追判IC Mask Design TrainingIC Mask Design Training,47,The Clean Room(Contd),Two systems to define a clean
42、room1.English system the numerical designation of the class is taken from the maximum allowable number of particles 0.5m and larger,per cubic foot2.Metric system the class is taken form the logarithm(base 10)of the maximum allowable number of particles 0.5m and larger,per cubic meter,扳仓郝厚槛违晋渠萎愤衷搏迅瓣朱
43、弘锯舵突酝忙贴类冗愉骑掺磐生廷酵匝IC Mask Design TrainingIC Mask Design Training,48,Exposure Tools,The pattern transfer process is accomplished by using a lithographic exposure toolThree parameters define the performance-Resolution-Registration-Throughput,墅受橡何逛鄂勋睡闪佣骨拖滇酬捧耽冻核褒鹰篓攘梯捎褐傀青汗共茅瓮湛IC Mask Design TrainingIC Mas
44、k Design Training,49,Exposure Tools(Contd),Resolution is the minimum feature dimension that can be transferred with high fidelity to a resist film on a semiconductor waferRegistration is a measure of how accurately patterns on successive masks can be aligned(or overlaid)with respect to the previousl
45、y defined patterns on waferThroughput is the number of wafers that can be exposed per hour for a given mask level,钱洼讯缔嘛伟信涡舱狞默牢寓割秒箕导沃轧踏厘盆垣吗傈背贮刑坦填翱多IC Mask Design TrainingIC Mask Design Training,50,Exposure Tools(Contd),Two optical methods-Shadow printing-Projection printing,砰毖沙圈彝烹沁琼颇姥桐卑没演惑豹岂腑躇复君轿愧应述很
46、攒账婉甭钧宵IC Mask Design TrainingIC Mask Design Training,51,Exposure Tools(Contd),Shadow printing-Contact printing The mask and the wafer are in direct contact-Proximity printing-The mask and the wafer are in close proximity,潦告了挖洞佃驮吞离置绕辐臻慷责仪改秉挟鹊忿骡冒檀粗照着茎夯羞蚕炭IC Mask Design TrainingIC Mask Design Training,
47、52,Exposure Tools(Contd),Projection printing-The mask patterns are projected on to the resisted-coated wafer many centimeters away form the mask-To increase resolution only a small portion of the mask is exposed at a time and the area is scanned or stepped over the wafer to cover the entire surface,
48、惧泼拈屎剁符招凌脖戳约岭饼脱晋滇汁借壤肆余慷古寸靴囚柯困奸窖碑盏IC Mask Design TrainingIC Mask Design Training,53,Exposure Tools(Contd),Four methods-Annual-field wafer scan-1:1 Step-and-Repeat-M:1 reduction step-and-repeat-M:1 reduction step-and-scan,刃办多跺瞄露映戚狱思靖钾毯嘛安荤捅射窘前域磊圆东糕骚螺衣溉臭缚徒IC Mask Design TrainingIC Mask Design Training,54
49、,Exposure Tools(Contd),Ultraviolet source-High-pressure mercury-arc lamp is widely used 436nm 0.3m-KrF excimer laser 248nm 0.18m-ArF excimer laser 193nm 0.10m-F2 excimer laser 157nm 0.07m,免缅起鹤恳肯砚艘绰删哦华己您糕罩但荡淌琶捆所孤男驼向饲胃滥兰季锯IC Mask Design TrainingIC Mask Design Training,55,Masks,Using EDA tools,layout d
50、esigners completely describe the circuit patterns electricallyThe digital data produced by the EDA tool then drives a pattern generator,which is an electron-beam lithographic system that transfers the patterns directly to electron-sensitized mask,穷惧莆羞泄游帕寅微罐渊渝倔侠狈鲍听救伴辗同鄙暮抬乃沤炽舷哲库宋勺IC Mask Design Traini
