Manufacturing Process of a Transmission Line

Step No.	General Step	Input	Detailed Step	Material	Temp./ºC	Time	Pressure	Other Data/Comments	Result/Output
Wafer 1: Cavity Wafer
1-1	Piranha Etch	plain wafer 1 500 µm	etch bath	H2O2:H2SO4 (1:1)	120	10min			cleaned wafer 1
1-2			rinse	H2O		~15 min
1-3			dry	N2
1-4	Opening of Vias	cleaned wafer 1	PECVD deposition of Si3N4 as masking layer	SiH4 - 100 sccm He - 990 sccm NH3 - 10 sccm N2 - 900 sccm	400	~6.5 min		thickness: 1000 Å power: 100 W rate: ~150 Å/min thickness:~1000 Å	wafer 1 w/ opened vias
1-5			adhesion promoter	HMDS		30 s		3500 rpm
1-6			wait			10 s
1-7			negative PR	AZ 5214		30 s		3500 rpm  thickness: ~1.5 µm
1-8			softbake		105	1 min		softbake on hotplate
1-9			mask alignment					mask: standard 4" chromium mask
1-10			exposure			4.5 s
1-11			hardbake		130	1 min		hardbake on hotplate
1-12			flood expose			90 s		expose w/o mask
1-13			development	MF 327		20-40 s
1-14			rinse	H2O
1-15			dry	N2
1-16			descum	plasma etcher w/ O2		1 min	250 mT	power: 100 Wr
1-17			Si3N4 etch	plasma etcher w/ CF4 - 25 sccm O2 - 0.5 sccm		5 min	250 mT	power: 100 W
1-18			removal of PR	ACE IPA		30 s 30 s
1-19			dry	N2
1-20			descum	plasma etcher w/ O2		1 min	250 mT	power: 100 W
1-21			Si etch	KOH:DI H2O (300 g:600 ml)	65	17.5 h		etch all way through wafer rate: 3.5h/100 µm
1-22			rinse	H2O
1-23			dry	N2
1-24			remove PR	ACE IPA		30 s 30 s
1-25			dry	N2
1-26	Lithography I: Cavity	wafer 1 w/ opened vias	adhesion promoter	HMDS		30s		3500 rpm	wafer 1 w/ PR patterned for cavity
1-27			wait			10 s
1-28			positive PR	1827		30 s		3500 rpm thickness: ~3 µm
1-29			softbake		105	1 min		softbake on hotplate
1-30			mask alignment
1-31			exposure			6 s
1-32			development	MP 351:DI H2O (1:5)		25 s
1-33			rinse	H2O
1-34			dry	N2
1-35			hardbake		130	1 min		hardbake on hotplate
1-36	Opening of Cavity	wafer 2 w/ PR patterned for cavity	SiO2 etch	BHF		8min		rate: 1000 Å/min	wafer 1 w/ opened cavity
1-37			rinse	H2O
1-38			dry	N2
1-39			remove PR	ACE IPA		30 s 30 s
1-40			dry	N2
1-41			Si etch	TMAH/H2O (22wt%)	90	~ 4.2 h		rate: 1 µm/min etch approx. 250 µm
1-42			rinse	H2O
1-43			dry	N2
1-44	Metallization	wafer 1 w/ opened cavity	evaporation	Ti 500 Å Al 15000 Å Ti 500 Å Au 3000 Å			<1*10-6 Torr		wafer 1 w/ metallized cavity
Wafer 2: Transmission Lines
2-1	Piranha Etch	plain wafer 2 500 µm	etch bath	H2O2:H2SO4 (1:1)	120	10 min			cleaned wafer 2
2-2			rinse	H2O		~15 min
2-3			dry	N2
2-4	Ground Plane on Bottom of Wafer 2	cleaned wafer 2	evaporation	Ti 500 Å Au 4000 Å			<1*10-6 Torr		wafer 2 w/ metallized bottom
2-5			electroplating	Au	?	?		current: ? mA thickness: 4.5 µm area: ? cm2 spin bar: ? rpm
2-6			rinse	H2O
2-7			dry	N2
2-8	Lithography I: Circuits	wafer 2 w/ metallized bottom	adhesion promoter	HMDS		30s		3500 rpm	wafer 2 w/ patterned PR for transmission lines
2-9			wait			10 s
2-10			negative PR	AZ 5214		30 s		3500 rpm thickness: ~1.5 µm
2-11			softbake		105	1 min		softbake on hotplate
2-12			mask alignment					mask: standard 4" chromium mask
2-13			exposure			4.5 s
2-14			hardbake		130	1 min		hardbake on hotplate
2-15			flood expose			90 s		expose w/o mask
2-16			development	MF 327		20-40 s
2-17			rinse	H2O
2-18			dry	N2
2-19			descum	plasma etcher w/ O2		1 min	250 mT	power: 100 W
2-20	Installation of Transmission Lines	wafer 2 w/ patterned PR for transmission lines	evaporation	Ti 500 Å Au 8000 Å			<1*10-6 Torr		wafer 2 w/ transmission lines
2-21			liftoff	PRS 2000	(hot)	30-60 min
2-22			rinse	H2O
2-23			dry	N2
Bonding of Wafer 1 & 2
3-1	Bonding	a) wafer 1 w/ cavities and slots b) wafer 2 w/ transmission lines	bonding layer	silver epoxy				applied around cavity on wafer 1 andon top of wafer 2	wafer w/ microshielded transmission line
3-2			fix wafer 1 on vacuum chuck of electrostatic bonding machine
3-3			place wafer 2 on hotplate beneath chuck
3-4			alignment
3-5			lower chuck w/ wafer 1 on wafer 2
3-6			bonding		150	10 min
3-7			cool down		to rm. temp.