The non parameterized element library is a resource of working MEMS devices and structures. The intent is to provide the novice MEMS designer easy access to MEMS designs without having to extract information from references and reinvent the wheel. This chapter explains how to use the non parameterized cell library. Section 2.1 describes how to browse and retrieve cells from the library database. The browser allows the user to peruse a brief description of cells and select desired ones. Section 2.2 details how users can submit their own designs for addition to the library once they have been fabricated and tested. While this may be unimportant to the novice user, we hope that experienced MEMS designers will contribute generously to the library as it is paramount to the success of the library. Section 2.3 and Section 2.4 describe some of the cells currently available in the library. The programs used are written in the Practical Extraction and Report Language, perl. Thus, perl must be available on the machine on which the library programs are installed.
A simple perl script, DBRetrieve, is available for cell retrieval. It can be accessed electronically via ftp using the following steps:
ftp mcnc.org Name: anonymous Password: ident cd pub/MEMS/NPCaMEL get DBRetrieve quit
This directory also includes a file named README.DBRead that provides further information about the installation procedure. To run the program type DBRetrieve and the rest should be self-explanatory. DBRetrieve is written in perl and utilizes a shell forms program called sf. The program will query the user for the cells desired then send mail to MCNC's cell library manager, which then extracts the design or designs and sends the layouts to the user. Designs are emailed to the user in either the CIF (CalTech Intermediate Form) or GDS II mask format.
DBRetrieve prompts the user for the mask format desired and browsing category. Designs may be browsed according to the process technology or the device design category. It is anticipated that the majority of designs will be for the MCNC MUMPs processes; however, the software is designed to include other processes as well. The design categories are currently test devices, motors, out-of-plane structures, linear actuators, and a miscellaneous category. Once these queries have been answered a sorted list will appear as shown in Figure 1.
1 (LIGA) [TEST] spiral, Allen Cowen 2 (UCB2poly) [TEST] 14v_220mA_fuse, G.K. Fedder/J.C. Chang/R.T. Howe 9 (MUMPS4) [TEST] Guckel_rings, Ramaswamy Mahadevan 3 (MUMPS3) [MOTORS] wobble_6_stator, Ramaswamy Mahadevan 4 (MUMPS3) [MOTORS] wobble_12_stator, Ramaswamy Mahadevan 6 (MUMPS3) [MOTORS] 12_stator_motor, Allen Cowen 8 (MUMPS3) [MOTORS] 12_stator_wobble_motor, Vijay Dhuler If you would like to see more information on a cell, please enter the number listed before the cell name. If no more information is desired, just type `.'. Figure 1. Window from DBRetrieve.
The user may then choose a cell and get further information about the device. An example of the information that will be available is shown in Figure 2. Finally, the user will be prompted for the desired designs, an appropriate email message will be sent automatically to MCNC, and the cell will be returned shortly to the user via email.
NAME: wobble_6_stator Cell NAME: wobble_6_stator, (MUMPS3) SIZE: Cell Width: 600 um Cell Height: 600 um DESCRIPTION: 6 stator wobble motor with a 50 micron radius. The motor was designed with the parameterized library. The dimples may need to be moved closer to the center. SUBMISSION DATE: Wed Jun 1 9:17:00 1994 AUTHOR: Ramaswamy Mahadevan MCNC Figure 2. Example of a manual entry for the 6 stator wobble motor.
DBSubmit is a program used to automate the submission of MEMS cells to the MCNC - ARPA cell library. It is written in perl and is designed to be easy to use. The first time the program is run it prompts the user for information about the designer, fabrication process, and design and sets up a template file. This template file can then be edited and used for subsequent submissions. The program, DBSubmit, can be retrieved in the same manner as described in Section 2.1. It is also located in pub/MEMS/NPCaMELand the file README.DBSubmit provides installation information.
In order to use this program, the $DB_PROC variable in the script must be set correctly. It should be set to the directory containing the database of process information. An updated set of this information can be obtained via anonymous ftp as explained below. If the directory variable is not set correctly, a directory named./DB_PROC is created automatically. New processes can easily be added by the user within the framework of the program. To set up the process database directory, first create a directory $PATH/dir for the data. Then obtain the process information via ftp using:
cd $PATH/dir ftp -i mcnc.org Name: anonymous Password: ident cd pub/MEMS/NPCaMEL/DB_PROC mget * quit cd ..
Before running the program DBSubmit, create a CIF or GDS II file with the mask layout of the design to be submitted. Do not forget to include definitions of any leaf cells that are called as instances within the main cell. DBSubmit is a forms based script that prompts the user for a number of items including name, address, cell descriptions, etc. Once the forms are filled out, the software will send the information to MCNC where the cell is entered in the library database and made available to domestic users. A file named cell_name.sbmt is saved in the user's directory and can be used for subsequent submissions by modifying the file and typing DBSubmit cell_name.sbmt. An example of a submission file is shown below with comments added after the pound (#) symbol.
# This is a completed template for the CaMEL DBSubmit program. To use # simply copy it to another file and strip off all the comments which # are anything after the # in a line. # *** CaMEL submission file *** # header Replacement file: n # Is this replacing another design Designer's name: Allen Cowen # author of the design Designer's affiliation: MCNC # author's affiliation Submitter's name: Allen Cowen # submitter of design Submitter's phone number: (919) 248-1424 Submitter's email address: firstname.lastname@example.org Submitter's address: # need a blank line after MCNC # the address PO Box 12889 3021 Cornwallis Road Research Triangle Park, NC 27709-2889 Design name: octagon # name to describe design Cell Width: 126.5 um Cell Height: 126.5 um Design description: # description should be This is an octagon. # followed by a blank line Format of data: 1 # [0-2] 0=CIF 1=GDSII 2=Tanner Method of transfer: 2 # [1-3] 1=ftp from your site # 2=ftp to our site # 3=email Internet path: mcnc.org # if method of transfer=1 File path: oct.gds # if method of transfer=1 File name: oct.gds # if method of transfer=2 File name: oct.gds # if method of transfer=3 Process Technology: LIGA # Name of technology used Process Facility: MCNC # Name of processing facility Device Tested: y # Was the device tested? Device Performance: # If the device was tested This device did not do very well. # give an explanation of It went this fast; but it broke down very # results followed by a blank quickly. # line. If not, take out Device # Performance line down to # blank line. Device yield determined: y Device yield: # Similar to device performance. This device's yield was 95%. # Take out if not determined. # The next line is the stream level for the only mask in the layout. electroplated nickel STREAM layer: 49 end_of_file
This section lists the cells currently in the database. It will be augmented as contributions are received.
TABLE 1. Index of cells currently in the library. ---------------------------------------------------------------------------- Refnum name process categ. author ---------------------------------------------------------------------------- 1 spiral LIGA TEST Allen Cowen 2 14v 220 mA fuse UCB2polyTEST GK Fedder, JC Chang RT Howe 3 wobble 6 stator MUMPS3 MOTORS Ramaswamy Mahadevan 4 wobble 12 stator MUMPS3 MOTORS Ramaswamy Mahadevan 5 simple hinge MUMPS3 OUTPLANE Kris Pister 6 12 stator motor MUMPS3 MOTORS Allen Cowen 7 linear actuator MUMPS3 LINACT Ramaswamy Mahadevan 8 12 stator wobble motor MUMPS3 MOTORS Vijayakumar Dhuler 9 Guckel Rings MUMPS4 TEST Ramaswamy Mahadevan 10 pad MUMPS4 OTHER Ramaswamy Mahadevan 11 resonant comb drive MUMPS4 LINACT Allen Cowen ----------------------------------------------------------------------------
Any of these cells may be obtained by sending mail to email@example.com with CaMEL retrieval file as the subject and the first line of the message body specifying the format desired [CIF/GDS] and subsequent lines the cell number corresponding to the designs listed above. The return email address is automatically extracted from the header. For instance, the following would return the 12 stator motor,
Please send the following designs in CIF format. 6
The following subsections show sample manual entries for the various cells in the library.
NAME: spiral Cell NAME: spiral, (LIGA) SIZE: Cell Width: 107.5 um Cell Height: 102.5 DESCRIPTION: This is a spiral spring with a 5 um beam width and 5 um spacing between turns. SUBMISSION DATE: Mon Mar 7 16:55:26 1994 AUTHOR: Allen Cowen MCNC
NAME: 14v_220mA_fuse Cell NAME: 14v_220mA_fuse, (UCB2poly) SIZE: Cell Width: unknown Cell Height: unknown DESCRIPTION: This is a fuse designed to blow at ~ 14 v or ~ 220 mA pulse. It has 6um allowable displacement in x and no constraint in y. SUBMISSION DATE: Tue Mar 8 13:51:54 1994 AUTHOR: G.K. Fedder, J.C. Chang, R.T. Howe Berkeley Sensors and Actuators Center
NAME: wobble_6_stator Cell NAME: wobble_6_stator, (MUMPS3) SIZE: Cell Width: 250 um Cell Height: 600 um DESCRIPTION: 6 stator wobble motor with a 50 micron radius. The motor was designed with the parameterized library. The dimples on the rotor could be moved closer to the center. SUBMISSION DATE: Wed Jun 1 9:17:00 1994 AUTHOR: Ramaswamy Mahadevan MCNC
NAME: wobble_12_stator Cell NAME: wobble_12_stator, (MUMPS3) SIZE: Cell Width: 250 um Cell Height: 600 um DESCRIPTION: 12 stator wobble motor with a 50 micron radius. The motor was designed with the parameterized library. The dimples on the rotor could be moved closer to the center. SUBMISSION DATE: Wed Jun 1 15:45:07 1994 AUTHOR: Ramaswamy Mahadevan MCNC
NAME: simple_hinge Cell NAME: simple_hinge, (MUMPS3) SIZE: Cell Width: 30 Cell Height: 33 DESCRIPTION: This is the standard hinge that we use to rotate structures out of the plane of fabrication. Hinge pin is 2um wide poly1. Yield: Device yield is probably better than 99%. Structure yield can be substantially lower (e.g. 0%) depending upon the complexity of the structure. In some cases it _is_ the hinges that actually fail, but this is typically due to a bad structure design. Device Performance: In general the hinge performance in MUMPS3 is acceptable, with some caveats. Due to undercut of poly1, a wider hinge pin may be desirable (3 um drawn seems to work ok). The poly 1 thickness is comparable to the ox1+ox2 thicknesses, leading to potential problems with the hinge pin sliding under the edges of the staple and breaking during assembly. If a bit of caution is used during assembly, these problems can be avoided. SUBMISSION DATE: Thu Jun 2 21:46:35 1994 AUTHOR: Kris Pister UCLA
NAME: 12_stator_motor Cell NAME: 12_stator_motor, (MUMPS3) SIZE: Cell Width: 710 um Cell Height: 710 um DESCRIPTION: This is a 12/8 stator/rotor salient pole motor with a 50 micron rotor radius. Device Performance: They worked successfully with excitation under 100 volts. SUBMISSION DATE: Wed Jun 8 10:13:57 1994 AUTHOR: Allen Cowen MCNC
NAME: linear_comb Cell NAME: linear_comb, (MUMPS3) SIZE: Cell Width: 144 Cell Height: 118 DESCRIPTION: This is a linear comb drive with 8 fingers on the moveable part. It has a 4 micron finger width, a 3 micron gap, and stator-rotor finger overlap of 30 microns. It was designed with the parameterized cell library. SUBMISSION DATE: Mon Jun 13 16:59:29 1994 AUTHOR: Ramaswamy Mahadevan MCNC
NAME: 12_stator_wobble_motor Cell NAME: 12_stator_wobble_motor, (MUMPS3) SIZE: Cell Width: 710 um Cell Height: 710 um DESCRIPTION: This is a 12 stator wobble motor with a 50 micron rotor radius. The bearing has a 10 micron radius. Device Performance: They worked successfully with excitation under 100 volts. SUBMISSION DATE: Mon Jun 13 17:04:36 1994 AUTHOR: Vijay Dhuler MCNC
NAME: Guckel_rings Cell NAME: Guckel_rings, (MUMPS4) SIZE: Cell Width: unknown Cell Height: unknown DESCRIPTION: This is a set of Guckel rings used to measure stress in the MUMPS wafers. They were generated using the parameterized element library. They have a 20 micron ring width and 10 micron beam width. The smallest ring has a diameter of 98 microns and the largest has a diameter of 718 microns. SUBMISSION DATE: Tue Jun 14 10:48:46 1994 AUTHOR: Ramaswamy Mahadevan MCNC
NAME: pad Cell NAME: pad, (MUMPS4) SIZE: Cell Width: 118 Cell Height: 118 DESCRIPTION: This is a pad to connect from the top metal level to both levels of structural poly and the lowest poly0 layer. SUBMISSION DATE: Mon Jun 27 9:49:24 1994 AUTHOR: Ramaswamy Mahadevan MCNC
NAME: resonant_comb_drive Cell NAME: resonant_comb_drive, (MUMPS4) SIZE: Cell Width: 330 Cell Height: 316 DESCRIPTION: This is a comb drive resonator with a folded beam suspension. There are two comb drives with 15 fingers on the rotor. The finger length is 40 um, width 3 um, air gap 3 um, and overlap is 20 um. The folded beam suspension has beams 150 microns long and 2 microns wide. SUBMISSION DATE: Wed Jul 13 9:34:46 1994 AUTHOR: Allen Cowen MCNC