Simple Process Sequences

This page allows you to quickly add some basic process sequences. Details are given below, and you can add the tools and descriptions by clicking the buttons below. Most of these sequences are designed for TRL users. If you are unsure about the sequences, and recipe parameters, please contact the staff in charge of the tool for a detailed discussion and advice.
Instructions: Expand the appropriate sequence, and click the "add" button to add the sequence to the current process.

Thin PhotoStandard thin-resist lithography, 1um (SPR700).

Step	Lab	Tool	Details
			Standard Resist Lithography
1	TRL	HMDS-TRL	Dehydrate and enhance adhesion
2	TRL	coater	Spin on 1um of SPR700 resist at 3500 rpm
3	TRL	hotplate1	Bake at 95C for 5 minutes
4	TRL	EV1	Expose for 2.5 seconds
5	TRL	photo-wet-l	Develop in CD-26 for 70 to 90 seconds and inspect under microscope
6	TRL	hotplate1	Hard-bake at 120C for 2 minutes

Goal: Prepare, coat, explose and develop sample with the MTL standard resist (SPR-700). This is the best choice for standard wet or dry etching steps.

Image Reversal PhotoImage reversal lithography, 1.5um (AZ5214E).

Step	Lab	Tool	Details
			Image-reversal Lithography
1	TRL	HMDS-TRL	Dehydrate and enhance adhesion
2	TRL	coater	Spin on 1.5um of AZ5214E resist at 3500 rpm
3	TRL	hotplate1	Bake at 95C for 5 minutes
4	TRL	EV1	Expose for 1.3 seconds
5	TRL	hotplate2	Image-reversal bake at 120C for 2 minutes
6	TRL	EV1	Flood expose for 60 seconds
7	TRL	photo-wet-l	Develop in AZ422MIF for 75 to 90 seconds and inspect under microscope

Goal: Prepare, coat, explose and develop sample with the MTL image reversal resist, typically for liftoff. This is the best choice for depositing metal with liftoff.

Metal Liftoff DepositionImage reversal lithography followed by metal liftoff.

Step	Lab	Tool	Details
			Image-reversal Lithography
1	TRL	HMDS-TRL	Dehydrate and enhance adhesion
2	TRL	coater	Spin on 1.5um of AZ5214E resist at 3500 rpm
3	TRL	hotplate1	Bake at 95C for 5 minutes
4	TRL	EV1	Expose for 1.3 seconds
5	TRL	hotplate2	Image-reversal bake at 120C for 2 minutes
6	TRL	EV1	Flood expose for 60 seconds
7	TRL	photo-wet-l	Develop in AZ422MIF for 75 to 90 seconds and inspect under microscope
			Liftoff Deposition
8	TRL	eBeamAu	Deposit ... nm of ... (less than 500 nm)
9	TRL	photo-wet-r	liftoff: soak in acetone, usually overnight. if needed, clean sample ultrasonic bath in fresh acetone

Goal: Deposition of metal film by liftoff. Maximum practical thickness is 500 nm or less. Au and Pt metal depositions can get expensive, and thicknesses of 100-150 nm are usually sufficient. Some metals (e.g. Au, Pt) may require an adhesion layer (e.g. 10 nm of Ti or Cr). Some metals can have high stress and can peel if too thick (e.g. Ni).

Thick Resist LithographyThick photoresist lithography, 8-10um (AZ4620).

Step	Lab	Tool	Details
			Thick Photoresist
1	TRL	HMDS-TRL	Dehydrate and enhance adhesion
2	TRL	coater	Spin on 8um of AZ4620 resist at 3000 rpm
3	TRL	hotplate1	Bake at 110C for 3 minutes
4	TRL	EV1	Expose in 8 intervals of 3 seconds with 6 second wait
5	TRL	photo-wet-l	Develop in AZ405MIF for 1-2 minutes and inspect under microscope
6	TRL	prebakeovn	Bake in 90C oven for 30 minutes

Goal: Prepare, coat, explose and develop sample with the MTL's thick resist (AZ4620). Thick resist is ideal for DRIE silicon etching (especially when going more than a few 10's of microns).

Through-Wafer EtchThick photoresist followed by Si-wafer through-etch (DRIE)

Step	Lab	Tool	Details
			Thick Photoresist
1	TRL	HMDS-TRL	Dehydrate and enhance adhesion
2	TRL	coater	Spin on 8um of AZ4620 resist at 3000 rpm
3	TRL	hotplate1	Bake at 110C for 3 minutes
4	TRL	EV1	Expose in 8 intervals of 3 seconds with 6 second wait
5	TRL	photo-wet-l	Develop in AZ405MIF for 3-5 minutes and inspect under microscope
			Through Etch
6	TRL	coater	Handle-mount wafer onto carrier with thick resist
7	TRL	prebakeovn	Bake in 90C oven for 30 minutes
8	TRL	sts-Pegasus	DRIE etch through wafer
			Dismount and clean
9	TRL	photo-wet-l	Dismount in acetone overnight and solvent clean
10	TRL	asher-TRL	Optional: Ash 1 hour to clean up any remaining resist residues

Goal: Prepare, coat, explose and develop sample with the MTL thick resist (AZ4620), handle mount and DRIE etch through wafer.

SU8 LithographySU8 Lithography

Step	Lab	Tool	Details
			Thick Photoresist
1	TRL	hotplate300	dehydration bake for 5 mins
2	TRL	SU8spinner	coat with SU8
2	TRL	hotplate300	prebake ... mins @ ...C
2	TRL	EV1	expose ... seconds on special SU8 holder
2	TRL	SU8spinner	develop ... mins in ...
2	TRL	hotplate300	hard-bake for ... mins at ...C

Goal: Prepare, coat, explose and develop sample with SU8. Different thicknesses will require different bake temperatures, so you need to check the manufacturer's datasheet for details. SU8 is not used for normal processing (for example, it can contaminate dry etchers) but is often used for making microfluidic molds. Please be familiar about the problems that SU8 can cause when it gets into non-SU8 tools.

6.152J Solar Cell Module6.152J Solar Cell Module - Process Flow

Step	Lab	Tool	Details
			Lab Session 1
1	ICL	DCVD	Deposit 10 nm of SiO2
2	ICL	DCVD	Deposit 60 nm of SiNx
3	ICL	UV1280	Measure film thickness and properties
4	ICL	pTrack	Spin on 1um of SPR700 resist
5	ICL	EV-LC	Expose with mask layer 1, 3.5 seconds
6	ICL	pTrack	Develop resist with CD26, standard recipe. Inspect under microscope
7	ICL	AME5000	Etch the frontside dielectrics using SF6 and recipe JK NITRIDE
8	ICL	AME5000	Etch the backside dielectrics and epi layer. Epi etch is Cl based, recipe BASELINE POLY
9	ICL	asher-ICL	Remove resist in 3 min ash
			Lab Session 2
8	ICL	premetal-Piranha	Prianha clean (1:3 H2O2:H2SO4) for 10 mins, then 15 second 50:1 HF dip
9	ICL	endura	Sputter 1 um of Al on the backside, followed by 2 um of Al on the frontside
10	ICL	pTrack	Spin on 1um of SPR700 resist
11	ICL	EV-LC	Expose with mask layer 2, 3.5 seconds, aligned to layer 1
12	ICL	pTrack	Develop resist with CD26, standard recipe. Inspect under microscope
13	ICL	rainbow	Etch the frontside metal until almost all Al removed
14	TRL	acid-hood	Remove the remainder of the metal with a wet Al etch
15	ICL	photo-wet-r	Remove the resist using acetone, followed by an isopropyl rinse
16	ICL	semZeiss	Optional - Inspect device in SEM
			Lab Session 3
15	Other	OutsideLab	Test devices in bldg 13

Goal: Use of the ICL tool set to fabricate the 3.155J/6.152J solar cells.