DE102007059279B3 - Device for testing the mechanical-electrical properties of microelectromechanical sensors (MEMS) - Google Patents

Abstract

Test device for testing the mechanical-electrical properties of MEMS, which contain mechanically oscillating parts (acoustic sensors) and are located in a plurality on a semiconductor wafer (1), wherein the test device (4) as a unit in the form of an extended probe card (sample card) Contact needles (5), from a sound source (6), located at a certain distance from the sound source reference sensor (7) consists of sound ducts and sound-absorbing elements, wherein the reference sensor (7) and the sound source (6) mounted on a connecting line so are that in the test case they lie in a line with the MEMS transmitter (2), and the distance of the sound source (6) to the lower edge of the test device (4) is dimensioned so that when resting on contact pads of the MEMS transmitter (2) Contact needles (5) and set distance of the test device (4) from the surface of the semiconductor wafer (1) equal distances of the reference sensor (7) and of the MEMS transmitter (2) from the sound source (6).

Description

The The invention relates to a special test device for rational Testing the mechanical-electrical Properties of MEMS with mechanically oscillating parts (acoustic Sensors) for the evaluation or description of the sensor properties. The centerpiece such acoustic sensors is a chip and it is manufacturing technology a more or less big one Collectively made on a semiconductor wafer.

In the publication: S. Michael et al. "Parameter Identification Of Pressure Sensors By Static And Dynamic Measurements ", DTIP 2007 of MEMS & MOENS, Stress, Italy, 25-27 April 2007, test devices for testing mechanical-electrical Properties of MEMS are shown which are electrostatically excited or be statically deflected by air flow.

the According to the prior art, the test of the individual acoustic Sensor after removal from the dressing of the semiconductor wafer and mounting the chip on a for the measurement suitable bracket piece by piece with sluice and discharge in acoustically subdued measuring rooms or measuring chambers made. This procedure carries the danger the damage of the sensor (many individual steps after singulation, z. As by pollution), it is complex and expensive.

Of the Invention is based on the object, a device for testing to propose acoustic microelectromechanical sensors, which the bypasses described disadvantages.

Is solved the task with in the claims 1 and 2 specified characteristics.

The objects the claims 1 and 2 have the advantages of being tested in the disc dressing, a high reproducibility of the acoustic conditions the measuring arrangement is ensured when using a controlled sound source, that the device also for the ultrasonic range is suitable and a high noise / useful signal distance through targeted application of damping elements guaranteed.

The Invention will now be described with reference to an embodiment with the aid explained the drawing. Show it

1 in a schematic representation of the vertical section of an arrangement consisting of a table (Chuk), a semiconductor wafer thereon with a MEMS sensor and a test device in the form of a provided with measuring tips probe card (probe card) with a sound source and a reference sensor, wherein the sound source on the Connecting line between the reference sensor and the MEMS sensor with the same distance from each of the sensors from the sound source and mechanical elements (damper, etc, not shown), with all parts are firmly connected or soundproof.

2 the vertical section through one too 1 similar test arrangement schematically shown with the difference that the sound source of the test device in relation to the connecting line between the reference sensor and MEMS sensor asymmetric, that is mounted on one side.

In both figures, the Hableiterscheibe ( 1 ), which the MEMS sensor ( 2 ), on a flat measuring pad (Waferchuck) ( 3 ) and is fixed there. The test device ( 4 ) is with the contact pins ( 5 ), which make electrical contact with the contact pads of the MEMS sensor ( 2 ) (contact pads of the MEMS sensor are not shown), with the MEMS sensor ( 2 ) connected. There are known per se precautions that allow to set a certain distance of the test device to the surface of the semiconductor wafer exactly, z. B. on an automatic tester, so that in each case the same paths for the acoustic signal from the sound source ( 6 ) to the reference sensor ( 7 ) and the MEMS sensor ( 2 ) are guaranteed. The sound source ( 6 ) transmitted acoustic signals propagate the same way on both sides and reach after passing through the same distance the reference sensor ( 7 ) and the MEMS sensor ( 2 ). The individual parts are firmly and tightly connected to each other for the acoustic signals and the side walls of the channels for the acoustic signal are soundproofed. The arrangement ensures largely the same acoustic conditions on the MEMS sensor to be tested ( 2 ) and the reference sensor ( 7 ). Changes in the acoustic characteristic of the system over a wide frequency range are thus similar in both directions to the sound conduction. The two sensors: MEMS sensor ( 2 ) and reference sensor ( 7 ) register equal sound pressure changes, in 1 with 180grd phase rotation to each other.

In the 2 shown, opposite the 1 modified arrangement of the sound source, makes it possible to record the signals without phase rotation with otherwise the same properties.

Next the usual Sensitivity at 1 kHz is also the possibility given to perform a frequency response consideration.

1

Semiconductor wafer with acoustic sensors

2

MEMS sensor (acoustic sensor)

3

table (Chuck)

4

test device (extended sample card)

5

contact needles

6

sound source

7

reference sensor

Claims (5)

Test device for testing the mechanical-electrical properties of MEMS containing mechanically oscillating parts (acoustic sensors) and in a plurality on a semiconductor wafer ( 1 ), the test device ( 4 ) as a unit in the form of an extended probe card (probe card) of contact needles ( 5 ), from a sound source ( 6 ), a reference sensor located at a certain distance from the sound source ( 7 ), consists of sound guide channels and sound-absorbing elements, the reference sensor ( 7 ) and the sound source ( 6 ) are mounted on a connecting line so that in the test case they are in line with the MEMS transmitter ( 2 ), and the distance of the sound source ( 6 ) to the lower edge of the test device ( 4 ) is dimensioned so that when on contacting islands of the MEMS transmitter ( 2 ) resting contact pins ( 5 ) and the distance of the test device ( 4 ) from the surface of the semiconductor wafer ( 1 ) equal distances of the reference sensor ( 7 ) and the MEMS transmitter ( 2 ) from the sound source ( 6 ) are present. Test device for testing the mechanical-electrical properties of MEMS containing mechanically oscillating parts (acoustic sensors) and in a plurality on a semiconductor wafer ( 1 ), the test device ( 4 ) as a unit in the form of an extended probe card (probe card) of contact needles ( 5 ), from a sound source ( 6 ), a reference transmitter located at a certain distance from the sound source ( 7 ), consists of sound ducts and sound-absorbing elements, the sound source ( 6 ) is mounted in such a way that in the test case it is asymmetrical on one side of the connecting line between MEMS sensor ( 2 ) and reference transmitter ( 7 ), and the distance of the sound source ( 6 ) to the lower edge of the test device is dimensioned so that when on Kontaktierinseln the MEMS transmitter ( 2 ) contact pins ( 5 ) and the distance of the test device ( 4 ) from the surface of the semiconductor wafer ( 1 ) equal distances of the reference sensor ( 7 ) and the MEMS transmitter ( 2 ) from the sound source ( 6 ) are present. Test device according to claims 1 or 2, characterized in that contact needles ( 5 ), Sound source ( 6 ), Reference transmitter ( 7 ), and sound guide channels as parts of the probe card are firmly and soundproof connected to each other and the sound guide channels are soundproofed. Test device according to claims 1 or 2, characterized in that the sound source ( 6 ) via damping elements with the contact pins ( 5 ), the reference transmitter ( 7 ) and the sound guide channels as parts of the test device is connected and these parts of the test device with each other firmly and soundproof are connected to each other and the sound guide channels are soundproofed. Test device according to one of the preceding claims, characterized marked that in automatic testers with accordingly adapted evaluation programs is used.