Contact Lithography Recipes

 

Below is a listing of contact lithography recipes for use with designated aligners.  Based on your sample reflectivity, absorption, and surface topography the exposure time parameters may vary.  This listing is a guideline to get you started.   The recipes are tabulated to give you the values of the key parameters you will need to establish your recipe.  For wafer cleaning and preparation including HMDS use, please refer to the cleaning and preparation section in the lithography section of this web site.   For best resolution using thin resists, you will need to remove any edge bead before contact and exposure.  Also, hard contact mode will give you the most intimate contact between sample and mask, giving the best resolution.  Post develop bakes (not listed) are used to make the resist more etch resistant and depend on subsequent processes. Unless otherwise noted, all exposures are done on silicon wafers.

Positive Resist

Unless otherwise noted, bakes are on hot plates and the exposure of the resist is done using no filtering at 7.5mW/cm2.  Power of the lamp is set using the 405nm (h-line) detector.

Resist	Spin Cond.	Bake	Thickness	Exp. Time	Developer	Dev. Time	Comment
SPR510A	4krpm/30”	95 C/60”	~0.9um	20”	MF701	30”	More Details Here
AZ4110	4krpm/30”	95 C/60”	~1.1um	8”	AZ400K:DI  1:4	50”
AZ4210	4krpm/30”	95 C/60”	~2.1um	13”	AZ400K:DI  1:4	70”
AZ4330	4krpm/30”	95 C/60”	~3.3um	18”	AZ400K:DI  1:4	90”
SPR220-3.0	3.5krpm/30”	115 C/90”	~2.5um	25”	MF701	50”	Post Bake 115 C /60” Better Cl2 etch resistance than 4330 More Details Here
SPR220-7.0	3.5krpm/45”	115 C/120”	~7.5um	60”	MF701	70”	More Details Here

 

Negative Resist

Unless otherwise noted, bakes are on hot plates and the exposure of the resist is done using no filtering at 7.5mW/cm2.  Power of the lamp is set using the 405nm (h-line) detector.  In general, many negative resists require post-exposure-bakes (PEB)/flood exposures in order to make the negative tone of the image.  All flood exposures are done in broadband light using any contact aligner.  Also, because the tone is negative, a shorter first exposure time will result in more undercut, which is desirable for single-layer lift-off processes.  Under these conditions more develop time will also give more undercut.

Resist	Spin Cond.	Bake	Thickness	Exp. Time	PEB	Flood	Developer	Dev. Time	Comment
AZ5214	6krpm/30”	95 C/60”	~1um	5”	110 C/60”	60”	AZ400K:DI  1:5.5 or MF701	60”   45”	Concentrated 400K Dev. Etches 5214
AZ5214	6krpm/30”	95 C/60”	~1um	10”	110 C/60”	60”	MF701	45”	Using i-line filter in MJB-3.  0.7um resolution possible
AZnLOF2020	3krpm/30”	110 C/90”	~2.1um	10”	110 C/60”		AZ300-MIF	60”	Use i-line filter For Undercut More Details Here

 

2-Layer Lift-Off 

Below are links to more detailed recipes using 2-layer processes for lift-off purposes.  For a general description of lift-off techniques, please see the lift-off techniques page in the lithography section.

2-layer positive and negative processes using PMGI as underlayer.