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| = Proximity Effect Correction = | | = Proximity Effect Correction = |
| Apart from conversion to V30 the prime use of Beamer is to do Proximity Effect Correction (PEC). This is done through the PEC node. The PEC node has a quite a few options and different ways to define a Point Spread Function (PSF). The PSF is a radially symmetric function around the beam spot that defines dose received by the resist both due to the incident beam but also from scattered electrons. The PSF used in Beamer can be defined in two ways; either based on gaussian functions where the user supplies the parameters used to define the functions, or the PSF can be based on Monte Carlo simulations of electron scattering. In any case the PSF is mainly dependent on beam energy (acceleration voltage) and substrate material. The JEOL 9500 system is always used at 100 kV, the Raith eLine system can however be used at any acceleration voltage between 1 and 30 kV. The PSF changes drastically with acceleration voltage and it is very important to use a PSF generated at the correct acceleration voltage. Beamer comes with its own Monte Carlo simulator called Tracer. In Tracer one can set up a substrate material stack and simulate electron scattering at the desired acceleration voltage. The PSF can be output as a file and loaded into Beamer for PEC. | | Apart from conversion to V30 the prime use of Beamer is to do Proximity Effect Correction (PEC). This is done through the PEC node. The PEC node has a quite a few options and different ways to define a Point Spread Function (PSF). The PSF is a radially symmetric function around the beam spot that defines dose received by the resist both due to the incident beam but also from scattered electrons. The PSF used in Beamer can be defined in two ways; either based on gaussian functions where the user supplies the parameters used to define the functions, or the PSF can be based on Monte Carlo simulations of electron scattering. In any case the PSF is mainly dependent on beam energy (acceleration voltage) and substrate material. The JEOL 9500 system is always used at 100 kV, the Raith eLine system can however be used at any acceleration voltage between 1 and 30 kV. The PSF changes drastically with acceleration voltage and it is very important to use a PSF generated at the correct acceleration voltage. Beamer comes with its own Monte Carlo simulator called Tracer. In Tracer one can set up a substrate material stack and simulate electron scattering at the desired acceleration voltage. The PSF can be output as a file and loaded into Beamer for PEC. |
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| =ChipPlace - easy dose test setup=
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| A pattern can easily be set up for a dose test using the ChipPlace module. In ChipPlace one can set up a pattern to be instanced a number of time and easily assign each instance a dose. The dose can be manually set or be linearly interpolated between a start and end value for the instanced array. The output of ChipPlace is a single pattern file with all array elements assigned to individual doses (shot ranks). This also works with patterns that already have PEC applied. In that case ChipPlace will create a combined modulation of the PEC modulation and the dose test modulation. In the example below we demonstrate how to set up dose test without PEC. If PEC is needed a PEC node can simply be added before the ChipPlace node. In the example we will use the '''Array_dots''' pattern found in the examples pane. It is a simple array of dots in a 100 x 100 µm<sup>2</sup> box. The procedure is
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| *Import a design
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| *Add the ChipPlace node
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| *In the '''Substrate''' tab define the substrate size. This is purely for visualization of how the pattern fits on the substrate
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| {| style="border: none; border-spacing: 0; margin: 1em auto; text-align: center;"
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| | [[image:BEAMER_1.png|800px]]
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| This example uses the '''Array_dots''' pattern supplied with Beamer. Image: Thomas Pedersen.
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| |}
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| {| style="border: none; border-spacing: 0; margin: 1em auto; text-align: center;"
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| | [[image:BEAMER_2.png|800px]]
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| Choose a substrate size to visualize placement within the substrate in ChipPlace. Image: Thomas Pedersen.
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| |}
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| *Go to the '''Array and Data tab'''
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| *Click '''Add Array'''
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| *In '''Data to place''' choose '''Chip'''. It will then take the pattern connected to the ChipPlace module
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| *Fill in array data in '''Repitition''' and '''Pitch''' to create as many dose test instance as you want. In this case we create a 10 x 2 array
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| *Choose '''Center''' in '''Position Mode''' to have everything centered in the final output pattern (V30 file)
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| *Click '''Assign Dose''' to open up the dose assignment page
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| *Choose '''Dose Series''' and enter a start and end value. This is relative dose, i.e. a multiplier on the base dose defined by RESIST in the SDF file
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| *Choose '''Raster X''' in '''Deploy Mode''' to increase dose from left to right for all rows
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| *Click '''OK''' in both open windows to see the result
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| This will produce a 10 x 2 array of the pattern with a relative dose from 1 to 2. Remember this dose factor is acting as a multiplier onto the base dose defined by '''RESIST''' in the SDF file. Thus if a base dose of 200 is defined by '''RESIST''' this setup will start at 200 µC/cm<sup>2</sup> and end at 400 µC/cm<sup>2</sup>.
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| {| style="border: none; border-spacing: 0; margin: 1em auto; text-align: center;"
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| | [[image:BEAMER_3.png|800px]]
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| The array and dose assignment can be set up with just a few inputs. Image: Thomas Pedersen.
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| |}
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| {| style="border: none; border-spacing: 0; margin: 1em auto; text-align: center;"
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| | [[image:BEAMER_4.png|800px]]
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| Indicated for each element in the viewport is relative dose X and array number (x,y). Image: Thomas Pedersen.
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| |}
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| To make analysis of the post exposure result easier let us add a dose label to each array element. This dose label will be exposed along with the pattern and thus when inspecting the result in SEM the (relative) dose will be visible next to the pattern. It is very easy to add:
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| *Go to the '''Texts''' pane in the bottom window
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| *Enter '''$DOSE_REL(3)$''' to have the relative dose printed with 3 decimals accuracy
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| *Choose array 1 in '''Array ID''' to assign the text label to that array
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| *Assign text labels to all array elements with the '''(*,*,2)''' command. The "2" sets the relative dose of the labels to 2
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| *Assign an y-axis offset of for instance -100 µm to avoid having the label printed on top of the pattern itself
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| *Assign a decent size in the '''Size''' window, 20 µm will work for most cases
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| *Click '''OK''' in the bottom of the window to return to the Beamer view
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| *Run the ChipPlace node to see the result
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| *Add an '''Export''' node and export the result as normal
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| {| style="border: none; border-spacing: 0; margin: 1em auto; text-align: center;"
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| | [[image:BEAMER_5.png|800px]]
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| Final result of the ChipPlace node with relative doses from 1 to 2, ready for export to V30. Image: Thomas Pedersen.
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| |}
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| {| style="border: none; border-spacing: 0; margin: 1em auto; text-align: center;"
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| | [[image:BEAMER_6.png|800px]]
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| Example of the added dose labels. Image: Thomas Pedersen.
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| |}
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| == Beamer ==
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| The following is a short walkthrough of the most frequently used features of Beamer. For a more in depth look at Beamer please refer to GenISys own [https://www.genisys-gmbh.com/in-action.html learning material found here.]
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| The BEAMER software is used to convert files from GDSII format to v30-format. The BEAMER software is manufactured by GenISys (www.genisys-gmbh.de) and the software is installed on the ebprep computer.
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| The main functions of BEAMER are:
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| <pre>
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| Module Function
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| Import Imports a GDS, CIF or v30-file
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| Export Exports to GDS, CIF or v30-format
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| Grid Modifies the base unit of the imported file
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| Fracture Optimizes the fracturing of the layout
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| Heal Removes overlaps in the layout and joins abutting polygons
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| Bias Adds or subtracts geometrical bias to the pattern
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| Merge Merges two layouts
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| Minus Subtracts two layouts
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| PEC Proximity Error Correction
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| Split Splits the output in two
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| </pre>
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| [[File:beamer11.jpg|500px]] [[File:beamer10.jpg|250px]]
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| To use the modules, they are dragged to the process flow area.
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| The inputs and outputs of each module are illustrated by white tags. Two modules are coupled to each other by positioning the input of e.g. the Export module on top of the output of the Import module. The input/output tags turns black when they are connected.
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| By clicking on active modules, the layout of the file becomes visible in the layout view area.
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| <br clear="all" />
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| = Simple conversion from GDSII to v30 = | | = Simple conversion from GDSII to v30 = |
