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Center of MicroNanoTechnology CMi

HIMT VPG200 home

 

Heidelberg Instruments VPG200 - Photoresist LASER Writer


Disturbance in Zone 05

As you may already know, an ASML DUV stepper will be installed in Zone 5. Actually access to the VPG200 is fully restablished. Components of the future equipment will be assembled soon. During some critical periods the access through the main zone 05 door will be canceled. In such a case your are authorized to accees the VPG200 from the back door of zone 06.


 

VPG200_view  

Booking info:

  • 30 min. slot.
  • Up to 7 full size exposure per hour
  • Upper limit = 9 slots
  • Notification for blocked write mode (Shared job)

Billing info:

  • This equipment has reservation fees
  • Charged: 6 min. + processing time

 

Reservation fees are suspended in case of maintenance



 

Precautions and Warnings

Manual loading of small wafers/chips is strictly forbidden. Use always carriers of SEMI'standard plates or wafers. For smaller chip size, a dummy wafer can be used as carrier platform but only after discussion with the CMi staff. ! Danger for nozzle write head crashes! Lower chip size limit is 18x18mm.

 Contamination of optics (1): The VPG200 is sensitive to contamination from the cleanroom air. Additional active filters are installed in the tool flowbox air circulation. Double-check that all window bays are closed when leaving the tool!

 Contamination of optics (2): The VPG200 use high intensity UV light which burns the resist at too high intensity level. Do not overexpose resist without checking which is the maximum intensity for each resist family recommended by CMi Staff.

Not adapted and contaminating optics
 AZ9260 at any thickness are forbidden to avoid resist particles projection directly on the front lens.
Use MLA150 at 405 nm wavelengh


Table of content: CMI

  1. Introduction
  2. Equipment Description
  3. Modus Operandi (Student)
  4. Configuration and Tool Specifications
  5. Advanced Operations
  6. Links to manuals and equipment supplier
  7. Results

 

I. Introduction CMI

The VPG200 (Volume Pattern Generator) of Heidelberg Instruments GmbH in Germany is mainly design to the production of Cr-masks for use with mask aligners. For very small production volume (prototyping) direct writing on Semi-Standard wafers can be proposed either for first layer writing with wafer centering on wafer edges or with overlay alignment using two magnifications set of camera.
A high power pulsed UV laser at 355nm is used for illumination. Two optical paths with 1024 pixel beam intensity modulator (linear array in X direction) are working in parallel for better uniformity. Writing is performed by using mechanical scan in Y direction synchronized with the pulsed laser light. Fast Z-control of front lens distance (autofocus) completes the exposure system. This combination offers a very high speed data flow at very high pixel density.

The VPG200 is compatible with CAD-generated layout of standard file formats (GDSII, CIF, DXF). Bit exposure inversion is available in a single click. A separate workstation is used for maximum throughput (off-line conversion of layout) independently of the usage of the tool. Many parameters are available at this step for customized applications (multi exposure for low sensitivity resist, spot beam corrections, reduced Y speed scanning).

Top side alignment (exposure overlay) using optional camera is available for direct wafer writing. Only close view a few hundred of micrometer field of view. Precise coordinates and precise pre-alignment of wafer during wafer handling from cassette to stage are required. Please consult the guide to photolitho routes for the best exposure method regarding resolution or throughput.

Configurable writing mode: Front lenses are mounted in an easy to exchange bloc commonly named Write Head (WH later on in this description). User will choose among many criteria (layout CRITICAL DIMENSION [CD], resist thickness, line roughness, layout density, layout periodicity) the best possible writing speed to resolution power ratio accordingly to his project requirement. Limiting factors are very often external to the tool specification. Ideally the resolution or CD is limited by the photoresist, wavelength and resolving power of the optics (numerical aperture, depth of focus) which determines the beam spot diameter at focus point. Stage ADDRESS GRID is much smaller than spot size which allow precise position interpolation. This means that the XY stage precision is not a limiting factor of the system.

Other features are:

 

II. Equipment Description CMI

User interface with multi-access level from extremely simple to more complex use (many options: customized wafer center and flat detection, customized focus region of interest, use of camera for manual or fully automated alignment, focus and fine exposure tuning, measurement mode).

Basic access use web style wizard for easy setup. This web style user interface is mainly used for mask fabrication and first exposure direct writing. Quick start manuals below refer to this web style user interface. Advanced manuals are available in section III of this document but require a second advanced training session to get specific access rights.

Variable front optics configuration are available for optimized resolution/speed application. Change of configuration are performed by user. Resolution and troughput is summarized in the following table.

TableI png

For Each above Write Mode enhanced quality can be obtained by applying a reduced writing speed. In such a case the exposure intensity must be reduced in proportion. Reducing wrting speed reduce throughput proportionnaly.
Ultimate structures dimension are obtained using specific CD offset and dose optimization. Tool stability allows reproducible production of single grooves or lines of 500nm width or arrays of lines with 1200nm periodicity.

III. Modus Operandi (Student)

Step 0: Booking policy

Note that data conversion is not including in booking.

Data conversion can be performed at any time on a separate OS workstation in a multiuser mode environment without login.

Assuming that data conversion is prepared in advance,

Quota and reservation fees penalties maybe applied to avoid overbooking.

Two configuration text field are required in the booking form to help user to prepare and share night job:

User Mode: value = Free, Shared night job

User Mode Value Comment
Free Default user mode 7:30 to 15:30
Shared Night Job First user contact all participants (by mail) for sharing cassette and write mode. Splitting for billing info send by mail to the staff.
Formation For Staff Only, Training mode

 

Alignment: value

Alignment Value Comment
No Student account, mask or wafer direct writing
20mm Only for overlay exposure on wafers. Advanced account with preliminary check of alignment accuracy (20mm write mode locked)
10mm Only for overlay exposure on wafers. Advanced account with preliminary check of alignment accuracy (10mm write mode locked)
4mm Only for overlay exposure on wafers. Advanced account with preliminary check of alignment accuracy (4mm write mode locked)

'?' is used to mark slots which are still to be defined by the first user request
'Formation' is reserved for training by the Staff

Step 1: Off-line setup and conversion of CAD-files on the linux workstation (left side of the main tool)

Draw your data using a dedicated software, recommendation are listed here: Prepare your design,

Do not switch off or reboot the station. Just types enter to exit sleeping mode (no user, no password required).
Download your layout file from a server or through web mail.
From input file top structure and layers can be selected or combined. Options according to speed, resolution and line width uniformity are selected at this stage according to table I:

 

Quick Conversion Manual: Convert your design

IMPORTANT: Autofocus limitation: Specifications above degrade very rapidly for layout too close by about 7mm from any part of the edge substrate. This limitation applies in particular for circular shape wafer. Presence of laser marking above the flat edge may also affect exposure quality far above the lower exposure.

Step 2: Setting up

Quick start: Carrier Exposure Wizard

Wizardly guided setting up starts from choice of cassette slot (single or batch), next assign each slot to its specific layout followed by a selection of only two parameters (-> Actual calibration for Cr-plates: VPG Intensity setup):

Finish the setup by options such as exposure count, pre-align and centering, auto-focus option.
Repeat until all slots in the batch is filled up or press "start processing" to switch to fully automatic execution mode.

Step 3: Handling

In multi-user mode, only automatic loading from cassette is allowed (Cr'blank or wafer). Handling is fully automatic accordingly to the options selected (wizardly mode).
Manual sample loading is exceptional and must be approved by the Litho Staff. In this case wizardly mode cannot be used. Supervision by the user during first sample is recommended.

attention Take care to wait for a possible exchange of the writing head.
Write head will be checked next to sample loading on the stage. If apply, system will ask and wait for the user to perform the exchange of WH. Job continue only if the exchange was performed correctly. Your bill run in case you don’t complete the exchange successfully.

. Mixing of write head (different front lens) require the presence of the user at each sample exchange in order to change writing head. Billing is not stopped during the idle time and will be charged to the user.

Next laser is directly focused at the center of the wafer after loading. Focusing and exposure starts after laser beam auto-calibration. Finally plate or wafer will be unloaded safely in the starting slot of the cassette.

IV Advanced Operations CMI

Direct Writing on Wafers

V. Configuration and Tool Specification CMI

The VPG200 system is equipped with:

The VPG200 system offers the following specifications (NB: Actual specifications from May 2018).

Table II png

NB: Maximum write speeds are obtained for large layout size (typical 115x115mm for Standard 5" Cr-plate). Initial calibration and stage initial positioning consume more time for smaller area. Depending of layout large no exposure area are skipped resulting in lower writing time.

VI. Links CMI

Student Mode

Advanced users

Heidelberg Instrument

Result and SPC

Mask Fabrication (in construction)

Overlay exposure (in construction)