The Multi-User MEMS Processes, or MUMPs®, is a well-established program that has run consistently since 1992. Over 80 full process runs have been completed and shipped over that time to hundreds of organizations. MEMSCAP offers three unique stand-alone, multi-mask MEMS processes in MUMPs® : PolyMUMPs, SOIMUMPs, and MetalMUMPs.
Why Use MUMPs® ?
How does MUMPs® Work ?
PolyMUMPs™
| In the early 1990's, PolyMUMPs was one of the few alternatives available to designers for making MEMS; consequently, the service was primarily used to create innovative devices and resultant Intellectual Property. Today, PolyMUMPs has taken on an much broader role as a process/program that can support a variety of initiatives. | |||
Many universities use the service today as a way to teach beginning MEMS design at the undergraduate level, using PolyMUMPs as the "example" process. In this environment, classes will study MUMPs® during the semester then submit a design and get chips back in time for the end of the semester. Another use for PolyMUMPs is as a benchmarking tool for software models and statistical studies, where theories are validated with measured data from actual, fabricated chips. PolyMUMPs chips also serve as a standard building block for larger scale systems, where the MEMS chip is only one piece of the overall system. PolyMUMPs' well-understood properties and predictable outcomes are advantageously leveraged to make MEMS the "black box" fixed-component. |
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![]() Figure 1: PolyMUMPs process cross section |
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About The Process ![]() |
PolyMUMPs is a three-layer polysilicon surface and bulk micromachining process, with 2 sacrificial layers and one metal layer. Eight mask levels create 7 physical layers. The minimum feature size in PolyMUMPs is 2um. Devices that can be made in PolyMUMPs include: Acoustics(microphones), Sensors, Accelerometers, Micro-fluidics, Robotics, and Display Technologies. |
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SOIMUMPs™
![]() Figure 2:SOIMUMPs process cross section |
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MetalMUMPs™
MetalMUMPs incorporates all three major MEMS processes: LIGA-like, thick metal electroplating, as well as bulk and surface micromachining. Very tall structures of Nickel, between 18-22um, can be built on top of polysilicon and nitride with a deep, KOH-etched trench underneath. Electroplated nickel is used as the primary structural material and electrical interconnect layer. Doped polysilicon can be used for resistors, additional mechanical structures, and/or cross-over electrical routing. Silicon nitride is used as an electrical isolation layer. Deposited oxide (PSG) is used for the sacrificial layers. The trench layer in the silicon substrate can be incorporated for additional thermal and electrical isolation. Gold overplate can be used to coat the sidewalls of nickel structures with a low contact resistance material. The minimum feature size in MetalMUMPs is 5um. Devices that can be made in MetalMUMPs include: Relays, Microfluidics, Magnetic Switches, and RF Devices. |
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![]() Figure 3: MetalMUMPs process cross section |