MEMS Test Stimuli
Test and calibrate your MEMS under actual working conditions
SPEA MEMS Test Units provide the physical stimulation required to test and calibrate a variety of MEMS and sensors, under their actual working conditions. They can be easily integrated into SPEA test handlers, to provide a flexible turn-key solution for the device final test: their modular design allows an easy conversion of the equipment from a device family to another, to answer ever-changing requirements.
The highest throughput is guaranteed by high multi-site test capability, combined with the possibility to equip multiple test stages simultaneously inside the handler: as many as 392 devices can be contacted and tested simultaneously.
All test units are also available in an engineering lab version, as stand-alone units offering direct and safe access to the operator for the device loading.
Low g and gyroscopes
SPEA Rate Tables are a family of multi-axis positioners for testing MEMS accelerometers and gyroscopes. They allow the multi-site testing of up to 140 devices simultaneously, while providing precise and reliable angular position, rate and acceleration motion. Constant velocity is applied for accelerometers, while sinusoidal angular rate input is provided for gyro test. The axes are driven by torque motors, which ensure enhanced position and velocity accuracy.
The system interface, with up to 1500 x 2 wires, links the device output pins directly to the measurement instrumentation, so as to perform all the parametric measurements during the MEMS stimulation.
The Rate Tables are easy to operate: it is very simple to set instruction sequences, use direct move commands, and start the electrical measurements of the device.
They can either be embedded in integrated MEMS test cells (complete with test handler and test resources), or used as engineering units, connected to the test system, in order to perform mass production as well as engineering and prototype testing.
- High multi-site MEMS contacting unit: up to 140 devices tested in parallel
- Gyroscope test: constant velocity (trapezoidal profile with programmable velocity), sinusoidal and combined sinusoidal profiles with programmable amplitude and frequency
- Precise absolute positioning mode for accelerometer test
- High rate accuracy with no drift, excellent rate stability, high torsion stiffness
- Continuous connection to the tester during operation
- Programmable movement profiles through DLL instructions
- Accurate and reliable motion control, achieved by a servo- controlled system consisting of direct-drive DC torque motors with precise incremental optical encoders
- HF option with reserved wires for high-frequency signals up to 25MHz
- Automatic contactor cleaning and automatic device alignment, for high operation autonomy
- Device power with Kelvin contacts
- Nitrogenless tri-temp conditioning (range: -50 to 150°C)
High g
SPEA provides high g test units, designed for the best-performance production testing of high-acceleration MEMS inertial sensors, ideal for automotive components: A high-precision actuator shakes the devices applying up to 28g of acceleration, at up to 120Hz of frequency, under the required temperature conditions.
MEMS devices can be stimulated in XYZ simultaneously, saving on cycle time numbers with all related advantages in terms of test time (especially when several test passages at temperature are required) and minimized risk of device damage.
The modules offer top performance level, with less than 1.5% harmonic distortion at 28g / 90 Hz stimulation. The actuator is mounted on damping supports, while the unit chassis is made of natural granite, so as to offer best shake characteristics.
- XYZ simultaneous shaking stimulus
- Tri-temperature test
- up to 28 g / 120 Hz
- Harmonic Distortion <1.5%
- Multi-site capability: up to 49x
- 1,440 wire interface to tester
- Nitrogenless tri-temp conditioning (range: -50 to 150°C)
Pressure and environmental
SPEA pressure and environmental test units are designed for the high-performance production test of absolute and differential MEMS pressure sensors for a variety of applications, including consumer barometric, industrial, TPMS, environmental.
The integration with pick & place handler and test system provides a high-efficiency turn-key solution for lowering the cost of test: in a completely automatic machine, up to 392 devices can be contacted and tested simultaneously.
Up to 3 different test chambers can be installed within a single module, with independent generators, indicators and contacting units. The test chambers are specially designed to avoid any leakage, guaranteeing the best pressure accuracy during the test.
Dedicated controllers and thermal units allow the dynamic change of pressure and temperature values independently, even during the test execution. Temperature is generated and maintained by a fast thermal conditioning system, while the thermal chuck is placed directly in contact with the DUT, in order to ensure an optimum thermal transfer. Fast temperature change system (typical 2°C/s heating/cooling) allows the test of the devices at different set temperatures with only one pick-and-place insertion.
Pressure ranges:
- Barometric pressure range: 0.03 to 0.13 MPaA (0.3 to 1.3 barA)
- TPMS pressure range 1: 0.03 to 1.6 MPaA (0.3 to 16 barA)
- TPMS pressure range 2: 0.03 to 1.1 MPaA (0.3 to 11 barA)
- Differential pressure range: -0.07 to 0.4 MPa (-0.7 to 4 bar)
- Extended pressure range: 0.03 to 7.05 MPa (0.3 to 70.5 barA)
Key features:
- High multi-site functional test: up to 392 devices tested in parallel
- Thermal + pressure + gas + temperature stimulus (-40 to 180°C)
- Best pressure stability
- Temperature change during test
- Fast pressure change, with up to 6 tanks to speed up the set point change and settling time
- Easy connection with SPEA testers, with up to 2,520 interface wires per chamber
Acoustic
SPEA acoustic test units are designed for the high-performance production test of MEMS microphones and speakers: They integrate all the elements required for both the electrical and functional tests of the devices, including the equipment for the verification of the microphone/speaker working.
Based on a high-insulation acoustic chamber, the microphone test unit is able to produce the exact acoustic replicate of the electric input signals provided by the test system, while insulating the device under test from all external noise. The acoustic stimulus is individual and fully independent on each test site. The excellent insulation allows accurate and repeatable measurements, even at low frequencies, and well-defined uniform test conditions.
- Accurate acoustic signal, up to 70 dB SNR
- Acoustic signal independently applied to each site: no need for anechoic room
- Perfect insulation from external noise
- High multi-site test: up to 98 devices tested in parallel
- Speaker and reference microphone per site
- AWG and digitizer per site, with amplitude controlled for each site
Acoustic measurements:
- Total Harmonic Distortion THD, THOD
- Rubb and Buzz
- Sound Pressure Level (SPL)
- Sound Pressure Level (SPL) Phase
Electrical measurements:
- Impedance
- Capacitance
- Leakage
- Open/Short
- Current Consumption
Light & imaging
SPEA light sensor test units are designed for the production functional test of proximity sensors, Time-of-Flight sensors, ranging sensors, UV and IR sensors.
The module integrates all the elements required for both the electrical and functional tests of the devices, including the equipment for the functional verification of the sensor working.
The sensor test is performed by measuring its feedback to a specific target placed at different, defined distances. Multiple proximity targets can be applied, changing distance, color, and light conditions (e.g. white light or IR illuminators).
A multi-station revolver unit allows the multi-stage operation on the test area: devices are tested on multiple stages in parallel, managing different test sequences on each stage. The first revolver station is dedicated to device loading/ unloading, while each of the others can house a different optical chamber box, with tester interface and contacting unit. Multiple targets can be placed on each stage, to functionally test the sensor working at different conditions of light intensity, color, distance. High-accuracy testing of UV sensors is based on AAA-class solar simulators.
Each test stage, each contacting unit, and each test module, is managed by a dedicated CPU, communicating with the test supervisor. This guarantees high operating speed, fast setup, and quick diagnostics. The test cell footprint is optimized by the high integration of modules and processes.
- High throughput: 48x multi-site
- Electrical + functional sensor test
- Distance, color, light conditions setup
- Multi-stage test on same machine
- Fast package changeover
Magnetic
SPEA magnetic test units perform the high-throughput final test of linear magnetic sensors, angular sensors, speed sensors, based on Hall, xMR, or different technologies. Each module integrates all the elements required for both the electrical and functional tests of the devices, including the equipment for the verification of the magnetic sensor working, and the thermal conditioning for tri-temp test, compliant to the automotive requirements.
Functional tests include frequency, duty cycle, rotation direction, magnetic field intensity, sensitivity, sensor calibration, and are performed in addition to the standard electrical test (open/short, leakage measurements, etc.).
The test sequence is performed guaranteeing high precision and stability, keeping low the cost of test by running in parallel on up to 49 devices.
The test units can generate 1D, 2D or 3D magnetic fields according to totally arbitrary waveforms, with frequencies above 2KHz, as needed by the specific application. Bidimensional, very high-strength magnetic fields can be generated to stimulate sensors that need tens of kiloamperes/meter to be properly tested.
Uniform magnetic fields can be static or rotating, and can be applied in all directions (360° rotation angle), with the possibility to accurately change their position so as to simulate different working conditions (including the “zero-field” case).
Specific test integrations are based on the most suitable technology: magnetic PCBs, socket coils, or permanent magnets can be used as field sources. The best solution will be applied to each device type according to the specific requirements.
