Manufacturing Process of a High Isolation Switch

Step No. General Step Input Detailed Step Material Temp./ºC Time Pressure Other Data/Comments Result/Output
1 Piranha Etch plain wafer etch bath H2O2:H2SO4 (1:1)   10 min     cleaned wafer
2 rinse H2O   ~15 min    
3 dry N2        
4 Lithography I: Transmission Lines cleaned wafer negative PR AZ 5214   30 s   3500 rpm
thickness: ~1.5 µm		 wafer w/ patterned PR for transmission lines
5 softbake   105 1 min   softbake on hotplate
6 mask alignment         mask: standard 4" chromium mask
7 exposure     4.5 s    
8 hardbake   130 1 min   hardbake on hotplate
9 flood expose     120 s   expose w/o mask
10 development MF 327   20-40 s    
11 rinse H2O   1 min    
12 dry N2        
13 Installation of Transmission Lines wafer w/ patterned PR for transmission lines evaporation Ti 500 Å
Au 8000 Å		     <1*10-6 Torr Temp is a complex thermodynamic problem wafer w/ transmission lines
14 liftoff ACE   overnight    
15 rinse H2O   2 min    
16 dry N2        
17 Deposition of  Si3N4  as Passivation Layer wafer w/ transmission lines PECVD deposition of Si3N4 SiH4 - 100 sccm
He - 990 sccm
NH3 - 10sccm
N2 - 900 sccm		 400 ~6.5 min 20-300 mT thickness: 1000 Å
power: 100 W
rate: ~150 Å/min		 wafer w/ transmission lines partially covered with Si3N4
18 positive PR AZ 1813/1827   30 s   3500 rpm 
thickness: ~1.3µm
19 softbake   105 1 min   softbake on hotplate
20 mask alignment         mask: standard 4" chromium mask
21 exposure     4.5 s    
22 development MF 327   20-40 s    
23 rinse H2O        
24 dry N2        
25 hard bake   130 1 min   on hotplate
26 Si3N4 etch plasma etcher w/ CF4 - 25 sccm
O2 - 0.5 sccm		   5 min 250 mT power: 100 W
27 removal of PR ACE
IPA		   30 s
30 s		    
28 Lithography II: Sacrificial Layer Underneath Bridge wafer w/ transmission lines partially covered with Si3N4 positive PR 1813   30 s   3500 rpm
thickness: ~1.5 µm		 wafer w/ sacrificial layer of PR
29 softbake   105 1 min   softbake on hotplate
30 mask alignment          
31 exposure     6 s    
32 development MP 351:DI H2O (1:5)   20-40 s    
33 rinse H2O        
34 dry N2        
35 hardbake   130 1 min   hardbake on hotplate
36 evaporation Ti 300 Å
Au 1000 Å
Ti 1000 Å		     <1*10-6 Torr  
37 Lithography III: Mask for Electroplating wafer w/ sacrificial layer of PR positive PR 1813   30 s   3500 rpm
thickness: ~1.5 µm		 wafer w/mask for electroplating
38 softbake   105 1 min   softbake on hotplate
39 mask alignment          
40 exposure     6 s    
41 development MP 351:DI H2O (1:5)   20-40 s    
42 rinse H2O   1 min    
43 dry N2        
44 etch Ti 1000 Å HF:DI H2O (1:10)   10-15s    
45 flood expose     2 min   expose w/o mask
46 development MP 351:DI H2O (1:5)   5-10 s   thin film of PR remainsto prevent plating on Ti
47 rinse H2O   1 min    
48 dry N2        
49 Plating of Bridge wafer w/ mask for electroplating electroplating Au   10-30 min   current: 4-10 mA
thickness: 1-3 µm
area: 1 cm2
spin bar: high rpm		 wafer w/ bridge on top of sacrificial PR
50 development MP 351:DI H2O (1:5)   1 min   remove scum layer
51 rinse H2O   1 min    
52 dry N2        
53 etch rest of Ti 1000 Å HF:DI H2O (1:10)   10-15 s    
54 rinse H2O   2 min    
55 dry N2        
56 etch sacrificial Au 800 Å Au etch   20-40 s    
57 rinse H2O   2 min    
58 dry N2        
59 Release of Bridge wafer w/ bridge on top of sacrificial PR echt Ti 300 Å HF:DI H2O (1:10)   5 s     wafer w/ released bridge
60 rinse H2O        
61 dry N2        
62 remove sacrificial PR beneath bridge ACE
IPA		   30 s
30 s		    
63 rinse H2O        
64 dry N2