DE102012203135B4 - Micromechanical sensor arrangement and a corresponding manufacturing process and use - Google Patents

Abstract

Micromechanical sensor arrangement with: a substrate (S; S1; S1 ') with a front side (V; V1; V1') and a rear side (R; R1; R1 '); with a first micromechanical sensor device (M1; M11; M11 ') and on the rear side (R; R1; R1') a second micromechanical sensor device (M2; M12; M12 ') is integrated, the first micromechanical sensor device (M11) an inertial sensor and the second micromechanical sensor device (M12) comprises a pressure sensor area or a magnetic field sensor.

Description

The present invention relates to a micromechanical sensor arrangement and a corresponding manufacturing method and a corresponding use.

State of the art

Micromechanical sensor arrangements are nowadays produced either as discrete sensors on their own chips or as integrated sensors together with an associated evaluation circuit. In the case of integrated sensors, there is either vertical integration, with the sensor being arranged above the evaluation circuit, or lateral integration, with the sensor being arranged next to the evaluation circuit.

In the case of lateral integration, the assembly of the sensor chip and the ASIC evaluation circuit chip next to one another requires increased lateral space, and cost-intensive electrical connections must be created between the chips. With vertical integration of the sensor chip and ASIC evaluation circuit chip, or vice versa, there are restrictions in the freedom of design and the overall height of the structure is also considerable.

The area of the chip intended for the evaluation circuit must go through a complex semiconductor process consisting of many steps and then the sensor process. This reduces the overall yield and usually leads to additional costs because the circuit area has to go through the sensor process steps and, conversely, the sensor area has to go through the semiconductor process steps.

This approach is only cost-effective if e.g. high process synergies can be used and the respective process yields are very high. A modular exchange of the ASIC circuit chip is not easily possible.

From the US 7 213 465 B2 the integration of a sensor element on the back of an ASIC circuit chip is known.

In JP H07-209327 A an acceleration sensor is described which comprises a substrate on the upper side of which a first sensor part is arranged, which measures an acceleration in the x-direction, and on the lower side of which a second sensor part is arranged, which measures an acceleration in the y-direction.

Disclosure of the invention

The present invention creates a micromechanical sensor arrangement according to claim 1 and a corresponding manufacturing method according to claim 5 and a corresponding use according to claim 9.

Preferred further developments are the subject of the subclaims.

Advantages of the invention

The micromechanical sensor arrangement according to the invention and the corresponding production method allow very cost-effective sensor production and enable a particularly space-saving and space-saving, small design for sensors and / or actuators. At the same time, the arrangement enables a modular structure that allows individual chips to be replaced by others without great development effort.

The idea on which the present invention is based consists in monolithically integrating at least two functional MEMS areas on a single substrate, the functional MEMS areas being integrated on opposite surfaces of the substrate. In the functional MEMS areas, sensors and / or actuators are implemented, which are preferably sensitive or react to different external, independent stimuli.

Optionally, at least one further structured substrate can be connected to the substrate with a functional MEMS area or as protection on at least one of the two surfaces by a bonding process.

In a preferred embodiment, one or more inertial sensor areas and a magnetic sensor area are provided on opposite surfaces of the same substrate.

In a further preferred embodiment, one or more inertial sensor areas and a pressure sensor area are provided on opposite surfaces of the same substrate.

Optionally, the two opposite surfaces of the substrate can be connected to one another by means of one or more through contacts.

A particularly preferred possible use of the micromechanical sensor arrangement according to the invention is to use it for navigation in mobile terminals.

The invention thus enables the integration of several MEMS functions on a substrate combined with a cost-effective vertical integration approach, the silicon area only going through two less complex sensor processes. The construction and connection technology is also simplified.

In principle, through the monolithic integration of various MEMS functions on a substrate, an increased pairing density and thus smaller components can be achieved. When integrating MEMS functions with different operating principles and functional layers (magnetic / capacitive), however, different functional layers are often required. If these various MEMS functions are produced according to the state of the art on a single surface of a substrate, there are generally only very slight process synergies and, at the same time, geometric restrictions arise for the design of the MEMS functions. In many cases, extra measures must be taken to avoid undesirable process interactions, e.g. Application of temporary protective layers. The yields of the MEMS processes for the various MEMS functions are multiplied with one another, which means that the process costs are higher than they should actually be.

The invention enables the integration of MEMS functions, in particular with different operating principles and functional layers, on different sides of a substrate, whereby the geometric restriction in the design of the MEMS functions is practically completely eliminated. If both MEMS processes can be run with a high yield, there is a cost advantage compared to discrete, lateral and vertical integration concepts.

If the two opposing surfaces of the substrate are connected to one another by means of through contacts, electrical connections only need to be created to one of the surfaces in order to be able to lead the sensor signals to the outside. This makes the packaging process cheaper. The process steps for producing the vias take place simultaneously for all components located on the substrate, and they can therefore - especially with many vias - overall be cheaper than a serial contacting process step creates when packaging the electrical connections on both surfaces.

Figure list

• 1 eine schematische Querschnittsansicht einer mikromechanischen Sensoranordnung gemäß einer ersten Ausführungsform der vorliegenden Erfindung;
• 2 eine schematische Querschnittsansicht einer mikromechanischen Sensoranordnung gemäß einer zweiten Ausführungsform der vorliegenden Erfindung;
• 3 eine schematische Querschnittsansicht einer mikromechanischen Sensoranordnung gemäß einer dritten Ausführungsform der vorliegenden Erfindung;
• 4 eine schematische Querschnittsansicht einer mikromechanischen Sensoranordnung gemäß einer vierten Ausführungsform der vorliegenden Erfindung; und
• 5 einen Fließplan eines Herstellungsverfahrens für eine mikromechanische Sensoranordnung gemäß einer fünften Ausführungsform der vorliegenden Erfindung.

The present invention is explained in more detail below with reference to the exemplary embodiments specified in the schematic figures of the drawings. Show it:

• 1 a schematic cross-sectional view of a micromechanical sensor arrangement according to a first embodiment of the present invention;
• 2 a schematic cross-sectional view of a micromechanical sensor arrangement according to a second embodiment of the present invention;
• 3 a schematic cross-sectional view of a micromechanical sensor arrangement according to a third embodiment of the present invention;
• 4th a schematic cross-sectional view of a micromechanical sensor arrangement according to a fourth embodiment of the present invention; and
• 5 a flow chart of a production method for a micromechanical sensor arrangement according to a fifth embodiment of the present invention.

Embodiments of the invention

1 shows a schematic cross-sectional view of a micromechanical sensor arrangement according to a first specific embodiment of the present invention.

In 1 denotes reference numerals S. a substrate, for example a silicon substrate, which has a front side V and a back R. having. A first functional MEMS area M1 is on the front V integrated, and a second functional MEMS area M2 is integrated on the back. A functional MEMS area should be understood to mean that at least one sensor and / or one actuator is formed in this area. K1 refers to an electrical contact surface on the front V , and K2 denotes an electrical contact surface on the back R. .

Such an arrangement of functional MEMS areas M1 , M2 on opposite pages V , R. of the substrate S. effective integration, low overall height and inexpensive process management can be achieved.

2 shows a schematic cross-sectional view of a micromechanical sensor arrangement according to a second specific embodiment of the present invention.

In the second embodiment according to 2 is the electrical contact compared to the first embodiment according to FIG 1 changed.

In particular, in the second embodiment there is an electrical contact surface K1 ' on the front side V provided, as well as one from an insulation layer I. surrounded electrical via D. , for example made of tungsten, in the substrate S. provided which of the second functional MEMS area M2 to the first functional MEMS area M1 runs.

In this way it can be achieved that during assembly only connections or wiring on the front V must be provided.

Of course, the substrate S. also several vias D. which correspond to the connections of the functional MEMS areas M1 , M2 connect.

3 shows a schematic cross-sectional view of a micromechanical sensor arrangement according to a third specific embodiment of the present invention.

In 3 denotes reference numerals S1 a first substrate which is on its front side V1 a first functional MEMS area M11 and on its back R1 a second functional MEMS area M12 having.

The first functional MEMS area M11 has sacrificial layers O1 , O2 and functional polysilicon layers F1 , F2 which have the core structure shown, for example, whereby inertial sensors can be realized.

The second functional MEMS area M12 has a magnetic layer stack, for example a NiFe layer stack MS, and conductor tracks LB, which can be connected to the outside through a contact hole KL.

Such an arrangement can be designed as a magnetic sensor, for example.

The first substrate is blocked S1 via a bond frame BR with a second substrate S2 which is a front page V2 and a back R2 having, being in the back R2 Cavities KA are provided.

Such a micromechanical sensor arrangement according to the embodiments can be used, for example, in a component for navigation.

4th shows a schematic cross-sectional view of a micromechanical sensor arrangement according to a fourth specific embodiment of the present invention.

In the fourth embodiment according to 4th the first substrate bears the reference number S1 ' and points on its front V1 ' a first functional MEMS area M11 ' on which the functional MEMS area M11 corresponds to the third embodiment.

On the back side R1 ' of the first substrate S1 ' is another functional MEMS area M12 ' provided, which can be configured as desired, for example in the form of a piezo sensor.

Via a bond frame BR is the first substrate S1 ' with the second substrate S2 ' connected, in this embodiment a further functional MEMS area M2 ' on the front side V2 ' of the second substrate S2 ' is provided, with the back R2 ' of the second substrate S2 ' as in the third embodiment cavities KA having.

The functional MEMS area M2 ' of the second substrate S2 ' has the same functionality as the functional MEMS area M12 the third embodiment, so the functionality of a magnetic field sensor.

By providing three functional MEMS areas M11 ' , M12 ' and M2 ' in two substrates, one substrate being used to cap the other substrate, the integration density can be further increased.

5 shows a flow chart of a production method for a micromechanical sensor arrangement according to a fifth specific embodiment of the present invention.

As in 5 shown, the manufacturing process for a micromechanical sensor arrangement begins according to 1 with step SS1 , in which a processing of the first MEMS area M1 according to 1 is made. The backside R. of the substrate S. is located on a clamping arrangement or is passivated.

At the second step SS2 the substrate is turned over S. .

In the third step SS3 then become the process steps for the second MEMS area M2 done on the back. During this time the front is located V either on a substrate or is passivated.

Following this is the micromechanical sensor arrangement 1 completed.

Optionally can also be a step SS4 done by the substrate S. is connected to a further substrate, for example as described in the third embodiment or fourth embodiment.

Although the present invention has been fully described above on the basis of preferred exemplary embodiments, it is not restricted thereto, but rather can be modified in many different ways.

Claims (9)

Micromechanical sensor arrangement with: a substrate (S; S1; S1 ') having a front side (V; V1; V1') and a rear side (R; R1; R1 '); wherein a first micromechanical sensor device (M1; M11; M11 ') is integrated on the front side (V; V1; V1') and a second micromechanical sensor device (M2; M12; M12 ') is integrated on the rear side (R; R1; R1') , wherein the first micromechanical sensor device (M11) comprises an inertial sensor and the second micromechanical sensor device (M12) comprises a pressure sensor area or a magnetic field sensor. Micromechanical sensor arrangement according to Claim 1 , wherein at least one via (D) runs from the first micromechanical sensor device (M1) through the substrate (S) to the second micromechanical sensor device (M2). Micromechanical sensor arrangement according to one of the preceding claims, wherein at least one further substrate (S2; S2 ') is bonded to the front side (V; V1; V1') and / or to the rear side (R; R1; R1 '). Micromechanical sensor arrangement according to Claim 3 , wherein the further substrate (S2; S2 ') is a cap wafer. Method for producing a micromechanical sensor arrangement according to one of the Claims 1 to 4th with the following steps: a first step (SS1) in which a first micromechanical sensor device (M1; M11; M11 ') is integrated on the front side (V; V1; V1') of a substrate (S; S1; S1 '); a second step (SS2), in which the substrate (S) is turned over; and a third step (SS3) in which a second micromechanical sensor device (M2; M12; M12 ') is integrated on the rear side (R; R1; R1') of the substrate (S; S1; S1 '). Procedure according to Claim 5 , wherein in a fourth step (SS4) at least one further substrate (S2; S2 ') is bonded to the front side (V; V1; V1') and / or to the rear side (R; R1; R1 '). Procedure according to Claim 5 , the rear side (R; R1; R1 ') being passivated during the first step (SS1). Procedure according to Claim 5 , the front side (V; V1; V1 ') being passivated during the third step (SS3). Use of a micromechanical sensor arrangement according to one of the Claims 1 to 4th in one component for navigation.

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