Fraunhofer Institute for Electronic Microsystems and Solid State Technologies EMFT
Piezo assembly in the Fraunhofer EMFT microfluidic lab
Microfluidic Lab
The installation and testing of microdosing systems requires a laboratory environment with high demands on technical cleanness and air-conditioning technology. Fraunhofer EMFT has an ISO Class 7 cleanroom of approx. 100 square meters available for this purpose. The laboratory provides space for ultra-clean assembly workstations under laminar flow conditions, manual or automated measuring stations for characterizing microdispensing systems, high-precision dynamic deflection measurements, cleaning workstations, the electrical connection technology and a pilot line for piezo assembly of micromembrane actuators.
Piezo mounting on wafer level |
Mounting of piezoceramics on membranes (silicon or stainless steel) by adhesive bonding. Using a dispensing or jetting process, adhesive is automatically applied to the appropriate areas of the substrate. With the help of a pick&place module, the piezoceramics are precisely placed and then the adhesive is cured. The process is available both on a dispensing robot for low throughput rates and on an SMD placer for high throughput rates. |
Preload of the piezoceramics |
Defined preload of the piezoceramics using a patented process. As a result, the piezoceramics have a pre-steering after assembly. This method is important for producing microfluidic actuators with extremely small dead volumes. |
Fluidic test at wafer level |
Fluidic characterization of pump chips on a fully assembled micropump wafer stack. The pump wafer is clamped in a fixture. Using an X-Y table, the individual pump chips are electrically contacted and controlled from the top side, while they are fluidically contacted from the bottom side. Characterization of the pump wafer with approx. 200 micropumps, incl. stroke volume, flow rate, backpressure capability and leakage rate. |
Micromounting of microfluidic systems |
Mounting of microfluidic systems under ultra-clean conditions: This includes prior component cleaning, mechanical assembly with low-outgassing bonding and clamping as assembly and connection technologies, electrical contacting by means of aluminum wire bonding or fine soldering, and final leak and quality tests. |
Topographical characterization of micromechanically fabricated structures |
Characterization of micromechanical structures by means of a chromatic topography measurement module, with which 1D, 2D and 3D measurements with a measurement resolution of 50 nm are possible. The measurement module is controlled by an X-Y stage. In addition to static measurements, dynamic measurements up to 10 kHz are also possible. |
Fluidic characterization of microfluidic devices |
Gravimetric measurements of flow rates (several scales with different resolutions down to 0.1 μg are available). Different anemometric flow sensors for liquids or gases, automated back pressure measurements. Experience with different media (water, air, oil, solvents, and others). Measurement of smallest leak rates (optical or capacitive) down to the μl/h range. |