Specific Process Knowledge/Lithography/EBeamLithography/JEOL 9500 User Guide

Purpose, location and technical specifications

Type and location of machine

The JEOL JBX-9500FS electron beam lithography system is a spot electron beam lithography system designed for use in writing patterns (10 nm - 1 µm) in electron sensitive resists. The JEOL JBX-9500FS was purchased in 2012 and is installed in E-1 and E-2 at DTU Nanolab. The main console of the e-beam writer is installed in E-2 which is a class 10 (ISO 4) cleanroom with tight temperature and moisture control. The computer controlling the e-beam (EWS/9500) and the computer supporting the conversion of e-beam files are located in E-1 which is a class 100 (ISO 5) cleanroom.

Training and authorization

• Only authorized users are allowed to use this machine.
• In E-2, all users must keep within the area between the front side of the machine and the table with the pre-aligner setup. Only JEOL staff or DTU Nanolab staff may access the backside of the machine.
• No users, not even authorised users, are allowed to load a substrate into the automatic cassette transfer system.
• After your exposure, fully trained users can unload their cassettes from the automatic cassette transfer system and unmount their substrates.
• If you are unable to unmount your substrates before another user requires the cassette, you must accept that either the next user or DTU Nanolab personel unmount your substrates.
• Training can be requested by sending a mail with relevant process flow to training@nanolab.dtu.dk

Original JEOL Manual

The original JEOL manual for the e-beam writer JEOL JBX-9500FS is located on the O-drive: O:\CleanroomDrive\_Equipment\E-beam

Techical Specification

The system can be characterized as follows:

• The spot beam for electron beam writing is generated by a ZrO/W emitter and a four-stage electron beam focusing lens system.
• The maximum frequency of the deflector scanner is 100 MHz, i.e. the minimum beam dwell time is 10 ns.
• The acceleration voltage is locked at 100 kV.
• The e-beam writer can pattern structures with a minimum resolution of 10 nm.
• The maximum writing field size is 1000 µm x 1000 µm.
• The machine has cassettes for 2", 4", 6" and 8" wafers and also dedicated cassettes for chips with slot dimensions of 4 mm, 8 mm, 12 mm, and 20 mm. See the Cassette specification page for more information.

Sample mounting

The JEOL 9500 system uses a proprietary sample cassette format and thus each sample must be mounted in an appropriate cassette. Cassettes are available for wafer sizes from 2” to 8”. Smaller chips must be mounted in dedicated chip cassettes with slots of four different sizes available. For more information on available cassettes and their specifications please refer to the JEOL 9500 cassette specifications page. As an example the 4" titanium cassette is shown below.

Back side (left )and front side view (right) of the 4" wafer titanium cassette (BSPCL-520).

If a cassette has been used recently it might be found on the cassette preparation table already, otherwise it will have to be retrieved from the cassette transfer system. This is done from the operation screen of the cassette transfer system.

Operation screen of the automatic cassette transfer system / auto stocker. Photo: Thomas Pedersen.

Retrieving a cassette from the automatic cassette transfer system

• Toggle the system to "Local" operation mode
• Identify the shelf number for the cassette in question
• Use the "shelf selector" to choose that number
• Press the transfer button to transfer it from the shelf to the port/door
• Once the robot is done, click "Open" to unlock the door
• Open door, retrieve cassette and place it on a layer of tissues on the cassette preparation table
• Close the door
• Click "Close" to lock the door
• Set the system back to "Remote" operation

Once the cassette is placed up-side down on the preparation table the slot cover can be removed by pressing down and rotating the spring loaded locking mechanism. The substrate can be placed in the slot using the vacuum tweezer found on the table. As the cassette is up-side down, the substrate must be loaded with resist side down.

Samples can be loaded into appropriate cassettes on the cassette preparation table. Photo: Thomas Pedersen.

The system is fitted with an auto stocker system that can store 10 cassettes. It is thus possible to prepare multiple substrates and define an automated job to execute exposure of several substrates across several cassettes. After sample loading the cassette must be placed in the automatic cassette transfer system. Users are NOT allowed to do this. Only Nanolab staff who are members of the E-beam Loading Team may place cassettes into the automatic cassette transfer system. Hence users must always contact the Nanolab E-beam loading team prior to exposure to have their cassette loaded into the cassette transfer system. The E-beam loading team can be contacted at [email]. Upon loading a cassette Nanolab staff will visually verify the sample has been installed and secured correctly. Incorrect sample mounting can lead to severe damage to the internal parts of the JEOL 9500 exposure system.

Any user found to load cassettes to the cassette transfer system themselves will be permanently excluded from using the JEOL 9500 system.

Nanolab staff member loading the 4" wafer cassette to the automatic cassette transfer system. Photo: Thomas Pedersen.

General rules for handling cassettes and mounting wafers and chips into cassettes:

• Always wear face-mask and a new pair of gloves
• Never put cassettes directly on the table; use lint-free cleanroom tissues
• Never touch the reference planes, i.e. the six polished areas on the front side of the cassette
• Never lift the cassette in the hook
• Always check the wafer for loose parts or flakes before loading. In case of loose parts or flakes, stop mounting, discard or rework the sample and rethink your process.
• Always check the cassette for loose parts, dust and particles.
• For chips: Make sure the chip size is at least 2 mm larger than the slot opening. Be careful when mounting the plate; it will get stuck easily if mounted askew.
• For wafers: When mounting a wafer, hold the spring (wafer securing pin) back when putting the wafer and the plate into the cassette, especially on the 2" cassette (the spring can lift the wafer). Tighten the leaf spring first, then release the spring and tighten the rotation lock lever.
• Inspect the front side of the cassette carefully after mounting the chip/wafer; a small gap between substrate and cassette will lead to a failure in HEIMAP and no exposure is thus possible.

Cassette transfer

Cassette transfer is controlled from the Loader program. If it is not open it can be opened from the EBX Menu by clicking Ldr.

All essential programs can be started from the EBX Menu.

The Loader window controls cassette exchange between the writing system and the cassette transfer system.

The Loader window shows available cassettes in the automatic transfer system and which cassette is currently inside the writing system. In this example cassette 10 is inside the writing system. Cassettes can be moved between the writing system and the transfer system with the Carry in and Carry out buttons. Carry in will move the selected cassette to the writing system while Carry out will move the selected cassette to the selected shelf in the transfer system. In order to move a particular cassette into the writing system the current cassette must naturally be moved out first.

The EXCH EVAC switch must always be left unchecked as in this example. If it is toggled on the exchange chamber (load lock) will be pumped down after a carry out operation and the next carry in operation must then wait for the pump down (15 min) before it can be executed. Always leave EXCH EVAC off.

Prior to exposure the chosen cassette has to be transferred from the cassette transfer system and to the main chamber. This is done from the “Loader” module by first moving out the current cassette from the main chamber and then moving in the cassette used for exposure. Carry out takes about 4 minutes while carry in takes about 15 min since the exchange chamber has to pump down to vacuum. The procedure is

• Make sure EXCH EVAC is toggled off
• Press Carry out to move the current cassette back to the shelf it was loaded from
• After about 4 min the status light will be solid green, select the cassette to use
• Press Carry in
• The system will be ready after about 15 min