Foundry Services: MOSIS as a model

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Foundry Services MOSIS as a model

• MOSIS MOS implementation service, ISI, 1980.

MOSIS

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Foundry Services and Standard Processes

• MCNC/MUMPS (now by Cronos)
• 3 level poly, no electronics
• started in 1992, now 6 runs per year
• LIGAMUMPS
• single level metal, no electronics
• Sandia
• 5 level poly, no electronics
• 1 level poly w/ quality CMOS
• CMOS post-processing
• EDP, TMAH, XeF2 (Parameswaran)
• Plasma (Fedder)

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MUMPS process flow
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MUMPS process flow
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MUMPS process flow
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MUMPS process flow
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MUMPS process flow
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MicroOptical Bench (Ming Wu, UCLA)
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MCNC/MUMPS layer thicknesses
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Design Rules

• Guidelines for communication between fab people
  and design people
• Generally not enforced
• MUMPS, 2um CMOS no
• HP sub-micron CMOS yes
• Often desireable to violate
• MUMPS process exploration, new devices, some
  previous design rule violations are now
  encouraged
• CMOS Parameswaran, Fedder style MEMS depends on
  design rule violations

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Design Rules

• Typically due to
• lithographic resolution limits
• lithographic alignment repeatability
• etching capabilities
• Most important Line/space
• due to lithography or etching
• varies from layer to layer
• varies near topography
• no guarantee of dimensions the lines will exist
  and be distinct.

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Design Rules
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MCNC/MUMPS Design Rules
Rules for line/space on all mask layers.
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MCNC/MUMPS Design Rules
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MCNC/MUMPS Design Rules
Examples for POLY2 from mems.mcnc.org/smumps/mrule
s
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Breaking the Rules

• Sub-minimum lithography
• risky, but often successful, especially in planar
  areas
• Breaching nitride (substrate contacts and opens)
• Stack anchor1 and poly1-poly2-via
• dont include poly1
• include poly2 for electrical contact to
  substrate, or remove to expose bare substrate
• Double-thick poly
• continuous sheet of poly1 enclosed in
  poly1-poly2-via
• poly2 structures on top

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MCNC/MUMPS access

• Cost is 3,500 per submission
• 1cm2 die area per submission
• 15 identical dice returned (2/mm2)
• Files are submitted by anonymous ftp
• Dicing, bonding, HF release are all available for
  additional cost
• Parameterized and static design cells are free
  online (CaMEL)
• Design services are available for additional cost

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MCNC/MUMPS process specs
Polys are compressive, nitride and metal (Cr/Au)
are tensile.
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MCNC/LIGAMUMPS
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MCNC/LIGAMUMPS Design Rules
A, W, L must be greater than or equal to 20.0
microns. Photoresist aspect ratio, L/W, must be
less than or equal to 10.