Sensor with a single electrical carrier means

Abstract

A sensor having at least one sensor element (1), at least one signal processing element (2), and a housing (7) which has at least one fastening means. An electrical interface is provided for electrically connecting the sensor. The sensor has an electrically and mechanically connecting carrier means (4) on which the at least one sensor element (1) and the signal processing element (2) are arranged and are electrically connected to the carrier means. The carrier means (4) is also at least electrically connected to the electrical interface.

Claims

1. A sensor comprising: at least one sensor element, at least one signal processing element, a housing which has at least one fastening means, and also an electrical interface for electrically connecting the sensor, the sensor has an electrically and mechanically connecting carrier means on which the at least one sensor element and the signal processing element are directly arranged on and are electrically connected to said carrier means, wherein the carrier means is also at least electrically connected to the electrical interface, the carrier means is in the form of a leadframe, and wherein the at least one sensor element and the signal processing element are arranged on the carrier means in the form of unpackaged semiconductor components as bare dies, wherein the unpackaged semiconductor components comprise a functional structure formed from a semiconductor material but that the semiconductor components do not have separate housings.

2. The sensor as claimed in claim 1, further comprising in that the sensor has a single carrier means.

3. The sensor as claimed in claim 1 further comprising the sensor has a transfer mold housing which completely or at least partially surrounds the at least one sensor element and the signal processing element and the carrier means.

4. The sensor as claimed in claim 3 further comprising the at least one sensor element and the signal processing element are at least partially covered by an encapsulation compound, within the transfer mold housing.

5. The sensor as claimed in claim 3 further comprising the transfer mold housing is completely or at least partially surrounded by an overmold housing.

6. The sensor as claimed in claim 1 further comprising the at least one sensor element is in the form of an inertial sensor element.

7. The sensor as claimed in claim 1 further comprising the sensor is in the form of a satellite sensor, and the sensor is in the form of a motor vehicle sensor.

8. The sensor as claimed in claim 1, wherein the leadframe entirely forms the carrier means.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIGS. 1 and 2a) and 2b) show schematic, exemplary illustrations of exemplary embodiments of the sensor in accordance with the present invention, and

(3) FIGS. 3 and 4 show schematic, exemplary illustrations of an exemplary production method for a sensor in accordance with the present invention.

FURTHER DESCRIPTION OF THE PRESENT INVENTION

(4) FIG. 1 shows a raw sensor from two perspectives, said sensor having a leadframe as carrier means 4. The sensor includes two adhesively bonded sensor elements 1 and a signal processing element 2 with which electrical contact is made by means of bonding wires 10 bonded to the leadframe 4. Sensor elements 1 and a signal processing element 2 are surrounded or accordingly injection molded by a transfer mold housing 5. The leadframe 4 includes two further encapsulations as transfer mold housings 5. Furthermore, the leadframe 4 is populated with additional electronic components 8, such as R, C, IC, diodes or at least one varistor, for example.

(5) FIG. 2 shows an exemplary sensor in the form of a surface-mounted component or so-called surface mounted device (SMD). The sensor has a sensor element 1 and a signal processing element 2 which are arranged on the carrier means 4a, according to the example in the form of a printed circuit board or PCB. Electrical contact is made with the printed circuit board 4a by means of press fit pins 11, wherein the contact region are cut out from the housing 7 of the sensor in the form of an overmold housing 7. In FIG. 2a), the overmold housing 7 has a recess/cutout in this contact-making region, in FIG. 2b) this contact-making region in arranged next to the overmold housing 7.

(6) FIG. 3 shows an exemplary production method for the sensor in accordance with this invention. Instead of the conventional two packaging steps for constructing a satellite sensor, only one step is requiredthe bare dies are arranged/mounted on the printed circuit board 4a as the carrier means and contact is then made with the housing and said housing is formed. The construction of a separate SMD which then additionally would have to be connected to the carrier means and would take up space is dispensed with.

(7) For PCB sensors and satellite sensors, the construction and connection technology of the bare dies and the flip-chip process is identical. Front-end equipment can equally be used for production.

(8) The glob top and transfer mold manufacturing processes for protecting the bare dies are identical. The printed circuit board can be completely or partially encapsulated by transfer molding.

(9) The modular production method illustrated in FIG. 4 preferably allows or comprises two main variants, as is schematically illustrated by way of example: On-board variant (SMD) illustrated in the upper portion of FIG. 4:

(10) The populated leadframe 4 with the contact-connected bare dies is preferably protected by a glob top or casting compound and a subsequent transfer mold or a complete/post-encapsulation process, for example by means of epoxy. This produces an SMD, that is to say a component which can be surface mounted (surface mounted device), which is soldered directly onto the PCB, printed circuit board, or electronic printed circuit board of a control device. Reflow soldering or hot-steam soldering are suitable soldering methods.

(11) Satellite variant (IS) shown in the lower portion of FIG. 4:

(12) The populated leadframe with the contact-connected bare dies is preferably protected by a glob top or casting compound and a subsequent transfer mold or a complete/post-encapsulation process, for example by means of epoxy.

(13) The contact pins are welded to the leadframe beforehand or, as an alternative, a cable can be fitted by so-called crimping or beading.

(14) The fastening parts can be inserted into the die and concomitantly encapsulated or subsequently introduced, for example by hot-embedding and/or ultrasound welding.

(15) Three sub-variants are possible in accordance with the above: a) The populated leadframe 4 is completely encapsulated by the housing. b) The populated leadframe is partially encapsulated by an open housing and closed by a casting compound and/or cover. The cover can be composed of a metallic or nonmetallic material. c) The populated leadframe is partially encapsulated by a holder (so-called carrier) which is composed of plastic, and then completely encapsulated by the housing.

(16) The proposed method and its variants or the sensor produced using said method have the following advantages according to the example:

(17) The processes of mounting, making contact and protecting the bare dies are identical for both variants.

(18) Instead of the conventional two packaging steps for constructing the satellites (IS), only one step is required (bare die.fwdarw.satellite product). The construction of a separate SMD is dispensed with.

(19) The construction and connection technology of the bare dies is identical, that is to say the same manufacturing devices (front-end equipment), for on-board and satellite solutions (SMD and IS).

(20) The glob top and transfer mold manufacturing processes for protecting the bare dies are identical.

(21) Passive elements without or with protection (glob top and transfer mold) can additionally be mounted on the leadframe, as schematically shown with reference to FIG. 1 by way of example.

(22) Furthermore, any desired modular expansions of the leadframe are possible, these carrying further additional circuits, as schematically shown with reference to FIG. 1 by way of example. These can be further bare dies (MEMS, ASIC) or other components (R, C, IC, diodes, varistors, LEDs, etc.).

(23) All modules can be designed without or with protection (glob top+transfer mold). If appropriately designed, only one mold tool protection is required for all of the modules.

(24) While the above description constitutes the preferred embodiment of the present invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope and fair meaning of the accompanying claims.