✨Self Aligned NMOS

Last Updated March 2026

• 952 Transistors per Chip

• 94% Yield

• 1.26V Threshold Voltage

• 5 um gate length

Process in Fabublox:

FabuBloxwww.fabublox.com

Step #	Step Name	Parameters	Comments	Layer Stacks
Unnamed Section
0	Substrate Stack	PolySi: 500 nm SiO2: 20 nm Si (lightly p doped): 525 µm
1	Acetone + IPA Clean (N2 dry)	Cleaning Agent: Acetone then IPA Ultra-Sonication: false	Squirt with Acetone, then IPA, then dry the surface with the N2 gun.
2	Spin-On Dopant	Spin-On Dopant Name: P504 Dopant Type: N Spin Speed: 4000 rpm Spin Time: 20 secs	P504 from Filmtronics must use filtered syringe tips
3	Dopant Diffusion	Diffusion Time: 15 mins Diffusion Temperature: 1100 °C Environmental: false	In tube furnace with fused quartz tube
4	Wet-Etch	Etch Time: 10 mins Etching Agent(s): 6:1 BOE Etch Temperature: 25 °C	BOE is HF + Ammonium Fluoride DI water rinse after etch
5	Acetone + IPA Clean (N2 dry)	Cleaning Agent: Acetone then IPA Ultra-Sonication: false	Squirt with Acetone, then IPA, then dry the surface with the N2 gun.
6	HMDS Vapor Prime	Deposited Monolayer: HMDS Layer Thickness: 5 Å	Not Using an actual vapor primer. Spin @ 3000 rpm for 20 s bake at 100C for 20 s
7	Spin Resist	Resist: AZ P4210 Resist Type: Positive Spin Speed: 4000 rpm Spin Time: 30 secs
8	Bake	Bake Temperature: 100 °C Bake Time: 90 secs
9	Stepper Lithography		Pattern 1 -Defining Gates
10	Develop	Developer: AZ 400K 3:1 (DI water : developer) Develop Time: 30 secs Develop Temperature: 25 °C	Develop time may vary, use current stable patterning process. Modulate exposure time and develop time as needed to achieve good pattern resolution
11	ICP-RIE	Etch Time: 90 secs Etch Gas Composition: SF6 Gas Flows and Ratios: 10 sccm RF Power or Voltage: 100 Watts Sidewall Angle: 0 °
12	Wet Strip Resist	Stripping Agent(s): Acetone then IPA	Squirt with acetone, then IPA, then dry with N2 gun
13	Plasma Descum	Gas composition: O2 10 SCCM RF Power: 100 Watts Time: 2400 secs	Alternatively, a shorter clean can be done before resist strip.
14	Wet-Etch	Etch Depth: 20 nm Etch Time: 20 secs Etch Rate: 80 nm/s Etching Agent(s): 6:1 BOE (HF)	BOE is HF + Ammonium Fluoride DI water rinse after etch
15	Spin-On Dopant	Spin-On Dopant Name: P504 Dopant Type: N+ Spin Speed: 4000 rpm Spin Time: 20 secs	P504 from Filmtronics must use filtered syringe tips
16	Bake	Bake Temperature: 200 °C Bake Time: 10 mins
17	HMDS Vapor Prime	Deposited Monolayer: HMDS Layer Thickness: 5 Å	Not Using an actual vapor primer. Spin @ 3000 rpm for 20 s bake at 100C for 20 s
18	Spin Resist	Resist: AZ P4210 Resist Type: Positive Spin Speed: 4000 rpm Spin Time: 30 secs
19	Bake	Bake Temperature: 100 °C Bake Time: 90 secs
20	Stepper Lithography	Exposure time: 8 secs	Pattern 2 N well (source/drain) region defining pattern. Note, this may overlap with the gate area and further effect PolySi dopant concentration.
21	Develop	Developer: AZ 400K 3:1 (DI water : developer) Develop Time: 60 secs Develop Temperature: 25 °C	Develop time may vary, use current stable patterning process. Modulate exposure time and develop time as needed to achieve good pattern resolution.
22	Wet-Etch	Etch Time: 10 secs Etching Agent(s): BOE 6:1 (HF)
23	Wet Strip Resist	Stripping Agent(s): Acetone then IPA	Squirt with acetone, then IPA, then dry with N2 gun
24	Dopant Diffusion	Diffusion Time: 30 mins Diffusion Temperature: 1100 °C Environmental: false
25	Wet-Etch	Etch Time: 10 mins Etching Agent(s): 6:1 BOE (HF)
26	Spin-Coat	Material: 700B Spin Speed: 4000 rpm Spin Time: 20 secs	700B from filmtronics
27	Bake	Bake Temperature: 200 °C Bake Time: 10 mins
28	Acetone + IPA Clean (N2 dry)	Cleaning Agent: Acetone then IPA Ultra-Sonication: false	Squirt with Acetone, then IPA, then dry the surface with the N2 gun.
29	HMDS Vapor Prime	Deposited Monolayer: HMDS Layer Thickness: 5 Å	Not Using an actual vapor primer. Spin @ 3000 rpm for 20 s bake at 100C for 20 s
30	Spin Resist	Resist: AZ P4210 Resist Type: Positive Spin Speed: 4000 rpm Spin Time: 30 secs
31	Bake	Bake Temperature: 100 °C Bake Time: 90 secs
32	Stepper Lithography	Exposure time: 8 secs	Pattern 3 - Defining Al contact areas
33	Develop	Developer: AZ 400K 3:1 (DI water : developer) Develop Time: 60 secs Develop Temperature: 25 °C	Develop time may vary, use current stable patterning process. Modulate exposure time and develop time as needed to achieve good pattern resolution.
34	Wet-Etch	Etch Time: 20 secs Etching Agent(s): 6:1 BOE (HF)
35	Wet Strip Resist	Stripping Agent(s): Acetone then IPA	Squirt with acetone, then IPA, then dry with N2 gun
36	Thermal Evaporation	Film thickness: 500 nm	Alternatively sputtering can be used depending on available lab tooling.
37	Acetone + IPA Clean (N2 dry)	Cleaning Agent: Acetone then IPA Ultra-Sonication: false	Squirt with Acetone, then IPA, then dry the surface with the N2 gun.
38	Spin Resist	Resist: AZ P4210 Resist Type: Positive Spin Speed: 4000 rpm Spin Time: 30 secs
39	Bake	Bake Temperature: 100 °C Bake Time: 90 secs
40	Stepper Lithography		Pattern 4 - Interconnect and contact pad definition
41	Develop	Developer: AZ 400K 3:1 (DI water : developer) Develop Time: 60 secs Develop Temperature: 25 °C	Develop time may vary, use current stable patterning process. Modulate exposure time and develop time as needed to achieve good pattern resolution.
42	Wet-Etch	Etch Time: 5 mins Etching Agent(s): Type A Al Etchant Etch Temperature: 40 °C New Field 1: stir speed 150 rpm	Heat Etch up for 5-10 minutes before begining. Di water rinse after etch. Etch rate to be around 90nm/minute with Type A Al etchant for the Evaporatied Al, and based off the evaporator QCM readings.
43	Wet Strip Resist	Stripping Agent(s): Acetone then IPA	Squirt with acetone, then IPA, then dry with N2 gun