Specific Process Knowledge/Lithography/EBeamLithography

The JEOL JBX-9500 electron beam lithography system is a spot electron beam type lithography system designed for writing patterns with dimensions from nanometers to sub-micrometers. The minimum electron beam is around 12 nm, the maximum writitng field without stitching is 1 mm x 1 mm.

The machine is located in a class 10 cleanroom (E-2) with tight temperature and moisture control. The room must only be entered when the machines or equipment inside the room is intended to be used.

Performance of the e-beam writer

Purpose	pattern an electron sensitive resist	Mainly for pattering structures with minimum feature size between 20 nm - 1 µm
Performance	Resolution	Minimum electron-beam size: 12 nm
	Maximum writing area without stitching	1mm x 1mm
Process parameter range	E-beam voltage	100kV
	Scanning speed	100MHz
	Min. electron beam size	10nm
	Min. step size	1nm
	Beam current range	0.1nA to 60nA in normal conditions (see available condition files here)
	Dose range	0.001µC/cm2 to 100000µC/cm2
Samples	Batch size	Wafer cassettes: 6 x 2" wafers 2 x 4" wafers 1 x 6" wafer Special wafer cassette with slit openings of 20 mm (position A), 12 mm (position B), 8 mm (position C) and 4 mm (position D).
	Substrate material allowed	Silicon wafers Wafers with layers of silicon oxide or silicon (oxy)nitride Wafers with layers of metal III-V materials Quartz wafers Pyrex wafers

Getting started

Only DTU Danchip personnel is allowed to load or unload cassettes to or from the machine

To request a training session or a time-slot for the e-beam, contact the e-beam team via this link: e-beam@danchip.dtu.dk'

You need 3-4 training sessions before being allowed to use the e-beam writer. You can get training in loading and unloading samples into a cassette, to optically pre-align the samples, to calibrate the writer, to perform 2nd alignment and start exposure. For safety reasons, the costumer is however not allowed to load or unload cassettes to or from the e-beam writer.

Before you request for a training, it is crucial to have your pattern ready in either tdb-format or GDSII format. Also, check your pattern in e.g. CleWin before requesting. In order to reach the files from the computers inside the cleanroom, it is recommended to either dropbox them or send them per email to yourself.

It is also recommended to gather as much knowledge about your e-beam run from your colleagues, i.e. which e-beam current, aperture and dose to use, which shot pitch (e.g. SHOT A,10). In order to get an overview of what an e-beam process requires, it is recommended to a assist a fully trained colleague of yours when she or he e-beam writes. Furthermore, please read the e-beam manual for more information on which parameters to use.

On the L-drive, a logbook for the e-beam writer can be found. Sheet 1 gives you an overview of which condition files (currents and apertures) have been in use recently by which user on which type of resist. On sheet 2 in this logbook you can find a writing time estimation program; please use this prior to requesting e-beam sessions. If in doubt how to use it, contact the e-beam team at [1].

There are 3 manuals for the e-beam writer:

• A user manual describing the standard procedure when e-beam writing
• A jdf-, and sdf-file manual describing how to prepare sdf-, and jdf-files (found under 'Technical Documents')
• A BEAMER manual describing how to convert your pattern file (GDSII-format) to v30-format (found under 'Technical Documents')

Process Flows

ZEP520A is used as a standard positive e-beam resist. A process flow for spinning, e-beam exposing and development of this resist can be downloaded here (word format): Process_Flow_ZEP.docx; please note that the individual steps of the process flow should be optimised to your specific processing technique, this process flow thus being a guideline.

You can use the SSE-spinner, the Manual Spinner 1 or the III-V spinner to coat wafer or chips with e-beam resist. Read more about these spinners here (opens in a new tab).

• ZEP520A (standard resist), FLOW
• table of available resists

Resist	ZEP520A	ZEP7000	PMMA	MMA	CSAR	HSQ/XR-1541	Ma-N 2403	Mr EBL 6000	AR-N 7520
Polarity	Positive	Positive	Positive	Positive	Positive	Negative	Negative	Negative	Negative
Manufacturer	ZEON	ZEON		AllResist	AllResist	DOW Corning	Micro Resist	Micro Resist	AllResist
Comments	Standard positive resist. Technical Report to be found here: ZEP520A.pdf	Low dose to clear. Used for trilayer (PEC-free) resist-stack. Please contact Lithography. Technical Report to be found here: ZEP7000.pdf	Technical Report to be found here:	Approved, not tested yet. Used for trilayer (PEC-free) resist-stack or double-layer lift-off resist stack. Technical Report to be found here:	Approved, not tested yet. Technical Report to be found here:	Approved, not tested yet. Should work quite similar as ZEP520A. Please contact Lithography. Technical Report to be found here:	Standard negative resist	CC	Negative resist to be tested soon.
Spinner	SSE, Manual Spinner 1, III-V Spinner	Manual Spinner 1, III-V spinner	Manual Spinner 1, III-V spinner	Manual Spinner 1, III-V spinner	Manual Spinner 1, III-V spinner	Manual Spinner 1, III-V spinner	Manual Spinner 1, III-V spinner	Manual Spinner 1, III-V spinner	Manual Spinner 1, III-V spinner
Developer	AA	AA	AA	AA	AA	BB	BB	BB	BB
Rinse	AA	AA	AA	AA	AA	BB	BB	BB	BB
Remover	AA	AA	AA	AA	AA	BB	BB	BB	BB
Process Flow (docx-format)	Process_Flow_ZEP.docx	Trilayer stack: Process_Flow_Trilayer_Ebeam_Resist.docx‎	AA	Trilayer stack: Process_Flow_Trilayer_Ebeam_Resist.docx‎	AA	BB	BB	BB	BB

Proximity Error Correction

• PEC in BEAMER
• trilayer flow, not tested

Charge dissipating agent

• Al coating, FLOW
• ESPACER, no flow yet