Specific Process Knowledge/Lithography/EBeamLithography/FilePreparation
Introduction
An e-beam exposure requires a v30-file, which contains information on the pattern to write, a jobdeck file (jdf-file), and a schedule file (sdf-file). The sdf- and jdf-file contain information about size and position of substrate, dose, current, and shot step. The sdf-file, jdf-file and v30-file are compiled to a magazine-file (mgn) on the 9500 computer.
When a magazine-file is prepared, the actual shot time can be estimated by the e-beam computer (9500).
Preparing a GDS file
If the layout is asymmetric, the conversion might result in an offset of the final layout onto the wafer. It is therefore recommended to symmetrise the layout, e.g. by inserting small structures in the corners of a rectangle that covers the layout.
How to convert to GDS in L-edit:
1 In L-edit, click File/Export Mask Data/GDSII
2 Choose Default GDSII unit: 1 database unit = 0.001 microns
Even though you do not export hidden layers or un-selected cells, unwanted layers might appear in the final GDSII file. Therefore, after conversion til GDSII, check your layout in a different layout viewer, e.g. CleWin (freeware), or BEAMER.
Converting from GDS to v30 (BEAMER)
The gds-file is converted to a v30-file by using the programme BEAMER. Please read the special BEAMER manual for a more advanced description of the BEAMER program.
- Open BEAMER.
- Drag the ‘Import’-module to the top-right window of Layout Beamer, open the gds-file to convert
- If the pattern has abutting polygons and even overlapping polygons which lead to double exposure, incorrect simulations etc., this can be fixed by running a ‘Heal’ program; drag the ‘HEAL’-module on top of the gds-file
- Drag the ‘Export’-module on top of the gds-file, export to the location ‘C:\1 gds files\name\date’. Export in JEOL52-format and change field-size to 1000µm x 1000 µm (under 'Advanced’). Click RUN on the Export-icon to execute the whole procedure
The gds-file is now converted to v30-format. In order to check the layout pattern double-click on the v30-module and and a VIEW LAYOUT window will open.
Preparing sdf and jdf files
Sdf- and jdf-files should not be created or edited in a regular notepad or wordpad program. Use only SuperEdi, which is freeware and available on the computers in the e-beam room. When you save a sdf- or jdf-file in SuperEdi, make sure to set the line endings to UNIX.
Both the sdf- and jdf-file should carry names using no capital letters.
You can find templates of sdf- and jdf-files in the folder home/eb0/jeoleb/job/templates on the 9500 computer.
Simple sdf and jdf files
sdf-file
The sdf-file contains a series of commands and parameters that specifies jdf filename, type
of cassette, shot pitch and condition file. It also specifies whether the pattern to be exposed requires alignment.
Below, an explanation of the template 'simple.sdf'. Note that semicolon outcomments the text:
___________________________________________________________________________ MAGAZIN 'SIMPLE1' The magazine name is SIMPLE1; max. 20 capital letters
- 6 Cassette from slot no. 6 is used
%4A Wafer of 4" in position A is exposed JDF 'simple',1 Layer block no. 1 of the jdf-file 'simple.jdf' is exposed ACC 100 Acceleration voltage of 100keV is used CALPRM '0.2na_ap5' The condition file 0.2na_ap5 is used DEFMODE 2 Both deflectors are used (default) RESIST 240 A dose of 240 µC/cm2 is used SHOT A,8 The shot step between individual beam shots is 4 nm OFFSET(0,0) An offset of 0 µm is applied in both X and Y
END After exposure, the stage is left empty, i.e. the cassette is unloaded
___________________________________________________________________________
Note that the unit in the SHOT command is in 0.5nm, i.e. 'SHOT A,16' gives a shot pitch of 8nm. If the next user of the machine has loaded a cassette in slot #10 and you wish to load that cassette after exposure, you can finalize the sdf-file with 'END 10'.
jdf-file
The jdf-file contains a series of commands and parameters that specifies what pattern (v30-file) is to be written where on the sample. It also specifies what calibrations are to be performed during writing.
The jdf-file 'simple.jdf' could look like this:
___________________________________________________________________________ JOB/W 'SIMPLE',4 4" wafer, jobname is 'SIMPLE', max. 20 capital letters
PATH DRF5M The DRF5M calibration is used (see section 3.3)
ARRAY (0,3,2000)/(0,3,3000) see note 1
ASSIGN P(1) -> (*,1) Pattern 1 is assigned to row 1-3 coloumn 1
ASSIGN P(2) -> (*,2-3) Pattern 2 is assigned to row 1-3 coloumn 2-3
SKIP (1,1) Nothing is assigned to chip (1,1)
AEND End-command to 'ARRAY'
PEND End-command to 'PATH'
LAYER 1 Start of layer block 1 P(1) 'template1.v30' Pattern 1 defined in 'template1.v30' P(2) 'template2.v30' Pattern 2 defined in 'template2.v30' SPPRM 4.0,,,,1.0,1 Beam parameters (default - see section 6.2) STDCUR 0.22 ;nA Beam current (in nA) used for writing, see note 2
END End of jdf-file ___________________________________________________________________________
Note 1: 9 chips are written, the upper left chip has center in (X,Y) = (0,0). The pitch between the chips is 2 mm in x-direction and 3 mm in y-direction.
Note 2: You should always add 10% to the current defined in 'STDCUR'; this ensures you work well below a scan speed of 100 MHz and thus gives room for a fluctuating current.
___________________________________________________________________________
Examples
| 2 wafers with separate jdf files | |
|---|---|
| Two 2” wafers are loaded in position 2A and 2B with separate JDF-files ('thomasjfeb242010’ and ‘jonaspfeb242010’ respectively). The 2" cassette is located in slot
no. 3 in the autoloader. After exposure, the cassette will be unloaded and stage left empty. | |
|
MAGAZIN 'PLAIN'
%2A JDF 'thomasjfeb242010',1 ACC 100 CALPRM '0.2na_ap5' DEFMODE 2 ;2_stage deflection RESIST 320 SHOT A,12 OFFSET(0,0)
%2B JDF 'jonaspfeb242010',1 ACC 100 CALPRM '0.2na_ap5' DEFMODE 2 ;2_stage deflection RESIST 250 SHOT A,8 OFFSET(0,0)
END | |
Example 2.1: Two 2” wafers are loaded in position 2A and 2B with separate JDF-files
('thomasjfeb242010’ and ‘jonaspfeb242010’ respectively). The 2" cassette is located in slot
no. 3 in the autoloader. After exposure, the cassette will be unloaded to slot no. 3 again.
___________________________________________________________________________
MAGAZIN 'PLAIN'
- ---------------------------
- WAFER #2A FOR THOMAS
- ---------------------------
- 3
%2A
JDF 'thomasjfeb242010',1
ACC 100
CALPRM '0.2na_ap5'
DEFMODE 2 ;2_stage deflection
RESIST 320
SHOT A,12
OFFSET(0,0)
- ---------------------------
- WAFER #2B FOR JONAS
- ---------------------------
- 3
%2B
JDF 'jonaspfeb242010',1
ACC 100
CALPRM '0.2na_ap5'
DEFMODE 2 ;2_stage deflection
RESIST 250
SHOT A,8
OFFSET(0,0)
- ---------------------------
END
______________________________________________________________________________
Example 2.2: An array of 20 chips is written on one 4" wafer. The first 10 coloums of the array is defined in layer block no. 1 of the jdf, coloumn 11-20 is defined in layer block no. 2 of the jdf. The two layer blocks uses different beam shot pitch and base dose. The two layer blocks must be called in two different sequences in the sdf-file.
______________________________________________________________________________
MAGAZIN 'LAYERS'
- ---------------------------------------
- THIS IS FOR WAFER #1 %4A
- ---------------------------------------
- 1
%4A JDF 'layers',1 ACC 100 CALPRM '0.2na_ap5' DEFMODE 2 ;2_stage deflection OFFSET(0,0)
- ---------------------------------------
- 1
%4A JDF 'layers',2 ACC 100 CALPRM '0.2na_ap5' DEFMODE 2 ;2_stage deflection OFFSET(0,0)
- ---------------------------------------
END 1
_______________________________________________________________________________
JOB/W 'TWOLAYERS',4 PATH DRF5M
ARRAY (-10000,20,2000)/( 10000,20,2000)
ASSIGN P(1) -> (1-10,*) ASSIGN P(2) -> (11-20,*) AEND
PEND
LAYER 1
P( 1 ) 'test2.v30'
SPPRM 4.0,,,,1.0,1
SHOT A,20
RESIST 220
STDCUR 0.22 ;nA
LAYER 2 P( 2 ) 'test2.v30' SPPRM 4.0,,,,1.0,1 SHOT A,40 RESIST 250 STDCUR 0.22 ;nA
END