MEM’s Computer Aided Design Dr. Lynn Fullerpeople.rit.edu/lffeee/MEMS_CAD.pdf · USING THE HP...

© March 31, 2004 Dr. Lynn Fuller, Motorola Professor

MEM’s CAD

Rochester Institute of TechnologyMicroelectronic Engineering

ROCHESTER INSTITUTE OF TECHNOLOGYMICROELECTRONIC ENGINEERING

3-31-2004 MEMS_LAB.PPT

MEM’s Computer Aided Design Dr. Lynn Fuller

Motorola Professor Microelectronic Engineering

Rochester Institute of Technology 82 Lomb Memorial Drive Rochester, NY 14623-5604 Tel (585) 475-2035 Fax (585) 475-5041 [email protected]

http://www.microe.rit.edu


MEM’s CAD


RIT MEMS DESIGN RULES

Microelectromechanical SystemsThe basic unit of distance in a scalable set of design rules is called

Lambda, λFor the current MEMS process λ is five microns (5 µm)The process has six mask layers (plus some special layers), they are:

Poly 1 Green (Layer 1)Via Holes Yellow (Layer 5)Anchor Red (Layer 2)Dimple Pink (Layer 50)Poly 2 Grey (Layer 3)Hub Red Outline (Layer 102)Pin Blue (Layer 4)

The following rules are shown as top views(looking down on the mask layers)


MEM’s CAD


DESIGN RULES

Minimum pad size for probing 100 µm by 100 µmMinimum pad size for wire connections 1000 µm by 1000 µmAll probe pads have metal top layer.

10 µm by 10 µm box needed in four corners of 4000 µm by4000 µm work space. (for maskmaking accuracy)

Include etch holes when making patterns for large areapoly-two regions for which the sacrificial oxide is to beremoved.


MEM’s CAD


LAYOUT RULES

Perfect Overlay Slight OverlayNot Fatal

MisalignmentFatal

Layout rules prevent slight misalignment from being fatal.Also, rules help make device performance consistent (minimumwidth for resistor will make values more consistent)


MEM’s CAD


RULES FOR THE POLY ONE LEVEL

10 by 10 µm

Layer 1 - Poly 1 (green)

Rule 1.1 Minimum Width Wz = 4 λ

Rule 1.2 Minimum SpacingSzz = 2 λ

Wz = 4 λ (20 µm)

Szz = 2 λ (10 µm)


MEM’s CAD


RULES FOR THE VIA HOLES LEVEL

10 by 10 µm

Layer 2 - Via Holes (Yellow)

Rule 3.1 Minimum Width Wv = 2 λ

Rule 3.2 Minimum SpacingSvv = 2 λ

Wv = 2 λ (10 µm)

Svv = 2 λ (10 µm)


MEM’s CAD


RULES FOR THE ANCHOR LEVEL

10 by 10 µm

Layer 3 - Anchor (Red)

Rule 2.1 Minimum Width Wa = 4 λ

Rule 2.2 Minimum SpacingSaa = 2 λ

Wmin = 4 λ (20 µm)

Smin = 2λ (10 µm)


MEM’s CAD


RULES FOR DIMPLE LEVEL

10 by 10 µm

Layer 4 - Dimple (Pink)

Rule 3.1 Minimum Width Wd= 2 λ

Rule 3.2 Minimum SpacingSdd = 2 λ

Wd = 2 λ (10 µm)

Sdd = 4 λ (20 µm)


MEM’s CAD


RULES FOR POLY TWO LEVEL

10 by 10 µm

Layer 5 - Poly Two (Grey)Rule 4.1 Minimum Width

Wp = 4 λRule 4.2 Minimum Spacing

Spp = λWp = 4 λ (20 µm)

Spp = λ (5 µm)Spg = 2 µm

Anchor

Comb Drive GapSpg = 2 µm


MEM’s CAD


RULES FOR THE POLY ONE, ANCHOR AND POLY TWO TOGETHER

Layer 1,2,3 Overlay (Extension)

Rule 1.3 Minimum Extension of poly one beyond anchor

Eza = 2 λRule 2.3 Minimum Extension of poly two beyond Anchor

Epa = 2 λRule 2.4 Minimum Extension of poly two beyond Dimple

Epd = 1 λ

(10 µm)

(10 µm)Epa

Epd


MEM’s CAD


CROSSECTION OF CANTILEVER

Poly 1

Poly 2

SacOx

Silicon Substrate

Si3N4


MEM’s CAD


CROSSECTION OF GEAR

SacOx

Silicon Substrate

Si3N4

Poly 2Poly 2Poly 2

Poly 3


MEM’s CAD


SIMPLIFIED PROCESS SEQUENCE

LPCVD Nitride OneLPCVD Poly One (0.5 µm)Dope PolyPhotlithography Poly OneEtch Poly OneLPCVD Nitride TwoPhotolithography ViaEtch ViaLPCVD Sac Ox (2.0 µm)Photolithography AnchorEtch AnchorPhotolithography DimpleLPCVD Poly Two (2 µm)Dope Poly TwoDeposit Aluminum Etch MaskPhotolithography Poly TwoEtch Poly TwoRelease by Etching Sac Ox

Poly 1

Poly 2

SacOx

Silicon Substrate

Si3N4


MEM’s CAD


LAYOUT OF A CANTILEVER


MEM’s CAD


LAYOUT OF A ELECTROSTATIC COMB DRIVE

Anchor

Comb Drive GapSpg = 2 µm


MEM’s CAD


MEMS MULTI-PROJECT CHIP

4mm by 4mmDesign Spacefor Each Project

Total 16 mm by16 mm for 16student projects


MEM’s CAD


SPRING 1997-98

CantileversSpringsAccelerometerPressure SensorsElectrostatic MotorMirrorsDiffraction GratingGearsPin JointsSliderMicrophone


MEM’s CAD


GCA, Canon, Karl Suss and ASMLAlignment, Resolution and Overlay Structures

Filename/tools/ritpub/alignment-marks/canon.gds or canon.iccel_1

/tools/ritpub/alignment-marks/gca.gds or gca.iccel_1

/tools/ritpub/resolution-overlay/canon.gds or canon.iccel_1

/tools/ritpub/resolution-overlay/canon.gds or canon.iccel_1

60 µm

35 µm45 µm

60 µm

5 µm

600µm

20µm

50 µm

170 µm

150 µm

y-directionMeasurement

x-directionMeasurement

Type20P-4F W=6µm

B=40µm

B

W

A=60µm

A

C=100µm

C

TYPE 0

2.0

1.5

1.0

2.0

1.5

1.0

100µm

10µm


MEM’s CAD


USING THE HP WORKSTATIONS AND MENTORGRAPHICS CAD TOOLS - GETTING STARTED

Usually the workstation screen will be blank, press any key to view a login window.Login: -------- Password: --------

The screen background will change and the control panel will appear. Click the left mousebutton on the terminal icon. A window will appear that says hp term on the top and has a unixprompt inside. Type the command ls at the prompt to see a list of directories and files, theaccount should be empty. Typing yppasswd will allow you to change your password if youwant to.

Type ic <RET>, it will take 20-30 seconds, then maximize the IC Station window by clickingthe left mouse button on the large square in the upper right corner of the IC Station window.


MEM’s CAD


USING THE HP WORKSTATIONS AND MENTORGRAPHICS CAD TOOLS - PROCESS AND GRID

In the session menu palette on the right hand side of the screen, under Cell, select Create,using the lift mouse button. For cell name type device# (the # assigned to you, no space).Also set the process to the RITPMOS process by typing /ritpub/process/ritpmos in the processfield and click on return OK. In the gray area under the banner at the top of the screen, theprocess should now read RITPMOS. Select other>show layer palette, click/drag on layers 1 to4 then press select. Layers colors and shading should appear in upper right corner.

A large window with a black background and white dots should appear. We can now checkthe grid settings. In the top banner choose Other > Window > Set Grid. Set the Snap to 10 forboth x and y, minor=1, major=10, then click on OK

The cursor position is given at the top center of the window. The layer being used and thenumber of items selected is shown at the top right. The 12 gray buttons which correspond tothe F1-F8 and 4 white buttons allow multiple functions. For example push F2 to (UnselectAll). To get the next function listed below that (Unselect Area) push shift and F2. To get thefunction listed on the bottom for the F2 key (Move) press the CTRL key and the F2 key.


MEM’s CAD


USING THE HP WORKSTATIONS AND MENTORGRAPHICS CAD TOOLS - PAD CELL AND LETTERS

From the banner at the top of the page choose Objects>add>cell. A tan pop-up window willappear at the bottom of the page. Type in the following cell name, all lower case,/ritpub/padframes/ritpmos/ritpmos_12_pads and click the left mouse button on the locationbutton. Then position the cursor at the origin 0,0 and click the left mouse button. Click theleft mouse button on the cancel button on the tan pop-up box. Press SHIFT and F8 to ViewAll. You should see a white box with ritpmos_12_pads written inside it. Type flatten andselect, OK. Press F2 to unselect all.

500 µm

100 µm

100 µm

Design Space

ABCDEFGHIJKLMNOPQRSTUVWXYZ00.;:=*/-+1234567890NPN PNP µMVDD VSS GNDSUB +V -V

Note: To get larger letters changethe scale to 4 when bringing in12pads before flattening. Thenflatten. Select and discard theenlarged pads and corner squares.


MEM’s CAD


USING THE HP WORKSTATIONS AND MENTORGRAPHICS CAD TOOLS - DRAWING

Select easy edit, Select Shape, Select Options and see the layer names, colors and shadingpattern. Draw boxes by click and drag of mouse. Unselect by pressing F2 function key.The Notch command is useful to change the size of a selected box or merge rectangularshapes into more complex objects. The following command will draw a 3000 µm by 3000µm box with level 5 color/shading. $add_shape([[0,0],[3000,3000]],5)

Draw circles by typing $set_location_mode(@arc) return. The following command willdraw a 100µm radius circle centered at (0,0) using 300 straight line segments.To reset to rectangles type $set_location_mode(@line) return.

Select objects by clicking or by click and drag. Selected objects will appear to have a brightoutline. Selected objects can be moved (Move), copied (Copy), deleted (Del) or notched(Notc). To unselect objects press F2.


MEM’s CAD


USING THE HP WORKSTATIONS AND MENTORGRAPHICS CAD TOOLS - OTHER

ZOOM IN OUT: pressing the + or - sign on right key pad will zoom in or out. Alsopressing shift + F8 will zoom so that all objects are in the view area. Select View and Areaon top banner then click and drag a rectangle will zoom so that the objects in the rectangleare in the view area.

MOVING VIEW CENTER: pressing the middle mouse button will center the viewaround the pointer.

LASER PRINT OUTPUT: Select File and Print, OK. This gives a laser printer output ofentire cell. Select printer mgcprec2, clear width, len, pages, scale by using backspace sonothing is in those boxes. Say OK.

PRINT PART OF LAYOUT: first create a panel. Under objects, select add a panel, nameit and click on rectangle symbol. Then use the left mouse button to drag a rectangle aroundthe objects you want in the panel to be printed. Then select File and Print and enter panelname, click on print set up, printer is mgcprec2, clear width, len, pages, scale by usingbackspace so nothing is in those boxes. Say OK.


MEM’s CAD



ADDING TEXT: From the banner at the top of the page choose Objects>add>cell. A tanpop-up window will appear at the bottom of the page. Type in the following cell name, alllower case, /tools/ritpub/padframes/ritpmos/ritpmos_12_pads and click the left mousebutton on the location button. Then position the cursor at the origin 0,0 and click the leftmouse button. Click the left mouse button on the cancel button on the tan pop-up box.Press SHIFT and F8 to View All. You should see a white box with ritpmos_12_padswritten inside it. Type flatten and select, OK. Press F2 to unselect all. Use select and copyto place letters you want. To change letters to a different layer use select and set layers.Don’t forget to delete the extra letters and numbers you don’t want.To change text size: Import the cell (F5) with scale option greater than 1 to increase thesize. Try 3 to make letters 100 um high.

orType $add_device(“$pgtext”), select layer and justification and type text, click OK,Type flatten, OKTo change text size, do the text as a separate cell. Import the cell (F5) with scale optiongreater than 1 to increase the size.


MEM’s CAD



COPY A CELL FROM A STUDENTS ACCOUNT TO ANOTHER ACCOUNT: Tocopy from one students account to another account first have a dropbox set up to receive thefile. (for example Dr. Fullers dropbox is /lffeee )

Once the file is saved exit ic.In the terminal window type dmgr_ic, find the design in the right panel of design managerclick on the icon, right click>edit>copy and type the destination ie: /dropbox/lffeee OK

Exit design manager and open a new terminal window. Change directory to the destinationby typing cd /dropbox/lffeee check to see that your files are there by typing ls (4 or 5 files)set the protection to allow the file to be read by typing /usr/bin/chmod 644

and /usr/bin/chmod 644 filename.*

Then the owner of the dropbox can read the files and add the cells to his design. By pressingF5 and typing /dropbox/lffeee/filename, and flatten.


MEM’s CAD



GRAB A PLOT IN TIFF FORMAT TO PUT IN POWERPOINT, ETC.: Open asecond unix window while viewing the chip layout (or any other display) in anotherwindow. Type xv, select option to grab and set pause to ~5 seconds, save to hp account as.tiff file. You will have ~5 seconds to bring up what you want to grab. Log on to hp accountfrom your pc and use FTP software to copy the file to your pc.

SETTING CELL ORIGIN: under CONTEXT


MEM’s CAD


REFERENCES

1. Principles of CMOS VLSI Design, 2nd Ed., Neil H.E.Weste,Kmran Eshraghian, Addison Wesley, 1993.2. Physical Design Automation of VLSI Systems, Bryan Preas,Michael Lorenzeti, Benjamin/Cummings, 1988.3. VLSI Engineering, Thomas Dillinger, Prentice Hall, 1988.


MEM’s CAD


REVIEW QUESTIONS

• Why is the poly two bigger than the anchor?• Why is poly one under the anchor?• Sketch the layout of a torsional mirror that can tip in two

directions.• Sketch the layout of a polysilicon inductor using the first 4

masks in this process.

MEM’s Computer Aided Design Dr. Lynn Fullerpeople.rit.edu/lffeee/MEMS_CAD.pdf · USING THE HP...

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