IC工艺技术3--刻蚀

2.3
Aluminum etch (铝刻蚀)
2.4
Nitride etch (氮化硅刻蚀)
2.5
Poly/silicon etch (多晶硅/单晶硅刻蚀)
2.6
DI water rinse and dry
3. Dry etch
3.1
Plasma Theory and application (等离子理论和应用)
• Ion milling, RIE or the plasma etch with enough
side wall passivation process.
• After etch, critical dimension has no change or
very slightly difference.
• Wafer surface wetting and contact with
etch chemical
• Chemical reaction takes place, soluble
byproduct formation.
• Remove by product from wafer surface
3.2
Type of plasma etch (等离子刻蚀种类)
3.3
Etching gases and pressure (刻蚀气体和低压）
3.4
Etch process highlight (刻蚀工艺简介)
3.5
Etch process parameter (刻蚀工艺参数)
3.6
Ion milling (离子铣)
• Cooling water(冷却水) • Gas cabinet / Gas line (气柜,气体管道) • Gas bottle(气瓶)
2.0 Wet etch
Advantage and disadvantage
• Chemical etch (化学刻蚀）--- isotropy • CD loss （线宽变小） • High particle contamination （高颗粒） • Unable for small geometry (不能用于小尺寸工艺) • Higher process cost （工艺费用高）
passivation process.
• It causes undercut during the etching and
change critical dimension.
Anisotropic etch (定向刻蚀)
Etch rotection
The etch rate (and uniformity) affects by
• Temperature • The slowest step of one of above step
2.1.2 Wet etch byproduct (副产物)
• Part of byproduct will be converted to
IC工艺技术系列讲座
第三讲
ETCHING 刻蚀
讲座提要
1. General
1.1
Isotropic/Anisotropic etch (无定向/定向刻蚀)
1.2
Facility(动力环境)
2. Wet etch
2.1
Wet etch mechanism （湿化刻蚀机理）
2.2
BOE etch （氧化硅刻蚀)
3.7
BCD plasma etching equipment and application
5. Next etch process 未来的刻蚀工艺
1.1 General
Isotropic etch (无定向刻蚀)
Etching has no direction.
• Wet etch or a plasma etch without side wall
water soluble material. (水溶性)
• Part of byproduct will converted to gas
form.
If the gas can not be removed from the wafer surface soon enough, the problem will occur * Block etch --- snow (雪花) * Hiding at edge of resist --- lifting (浮胶)
化学药品）
2.2.1 BOE etch
BOE (Buffer oxide etch) mixed with HF and NH4F
Chemical reaction
SiO2 + 6HF
• Most of wet etch process have high selectivity to
the under layer （高选择比）
• Fast throughput （产量高） • Low equipment (investment) cost （投资少）
2.1.1 Wet etch mechanism （湿化刻蚀机理）
2.1.3 Wet etch improvement
Improvement method
• Pre-wet --- wetting agent （湿润剂） • Agitation （搅动） • Circulation （循环） • Temperature control （温度控制） • Filtration （过滤） • In a vacuum （真空） • Spray etch （喷洒） • Vapor etch （蒸发） • Selection of high purity of chemical （选择高纯度
Isotropic etch (无定向刻蚀)
Resist
Anisotropic etch (定向刻蚀)
1.2 Facility
• DI water (去离子水) 17mhom • Drain(排水) • Special chemical dispose system
• Exhaust(排风) • Compress air and Nitrogen (加压空气,氮气) • In house vacuum(真空管道)