SI9300622A - Integrated circuit with magnetic sensor - Google Patents

Abstract

Integrated circuit with a magnetic field sensor (MS) which is produced on a silicon substrate (S) with another integrated circuit, comprises a flat coil (T) surrounding the active region (A) of the magnetic field sensor (MS) with its inner winding and produced in a first metal layer (M1) over the silicon substrate (S). The inner winding of the flat coil (T) is connected to a connection strip (SL1) via four inner connection contacts (K1) which are arranged symmetrically with respect to the magnetic field sensor (MS). The outer winding of the flat coil (T) is connected via an outer connection contact (K2) to a connection strip (SL2). The connection strips (SL1, SL2) are produced in a second metal layer (M2). The circuit according to the invention allows accurate self-calibration of the sensitivity and, in addition, fast self-testing. Compensation of the sensitivity variation with temperature and time as well as a non-ideal symmetry of the crossed embodiment of the magnetic field sensor and also of the offset voltage is furthermore made possible. <IMAGE>

Description

Integrated circuit with magnetic sensor

The subject of the invention is an integrated circuit with a magnetic sensor, in which active circuit an integrated circuit of the invention can generate a reference magnetic field.

According to the international patent classification, the invention is classified in class H 01L 27/22.

A technical problem solved by the invention is to design such an integrated circuit with a magnetic sensor that it can form a reference magnetic field for rapid testing or calibration of the magnetic sensor, to compensate for the temperature and time variation of the sensitivity of the magnetic sensor, and to compensate for such non-ideality in the cross-sectional symmetry of the magnetic sensor as a discharge voltage, while the magnetic sensor, within the range of normal supply voltages, should have the same capacity as other known integrated magnetic sensors.

Many integrated circuits with a magnetic sensor are known. The non-ideality of symmetry in the cross design of the magnetic sensor and the voltage of the magnetic stripe shall be compensated for by matching the corresponding elements of the magnetic sensor as closely as possible, or by the corresponding properties of other elements of the electronic integrated circuit. The magnetic sensor is tested in such a way that a magnetic field is created by means of a separate and separate device from the integrated circuit. For known integrated circuits with a magnetic sensor, the disadvantage is that it is not possible to easily detect the defect and to automatically correct long-term changes on the magnetic sensor or on the accompanying electronic circuit.

Said technical problem is solved by an integrated circuit of the invention with a magnetic sensor, which, together with the other integrated circuit, is made on a silicon substrate, characterized in that the planar coil which surrounds the active region of the magnetic sensor with its inner envelope is made in the first the metal layer above the substrate, and that the inner coil of the flat coil is symmetrically symmetrical with respect to the magnetic sensor of the mounted internal contact pins connected to a connecting strip made in the second metal layer which is made above the first metal layer and is the outer coil of the flat coil through an external connection contact connected to a connection strip made in another metal layer.

The integrated circuit of the invention with a magnetic sensor is further characterized by the fact that the inner sheath of the flat coil is away from the active area of the magnetic sensor by a minimum technologically achievable distance and that the first metal layer is distant from the bottom of the active region by a minimum technologically achievable distance and coils away from each other for the shortest technologically achievable distance.

The integrated circuit of the invention with a magnetic sensor is, according to known circuits, more reliable, since it is possible to quickly and easily detect the presence of a fault by creating a magnetic field using its own flat coil. The magnetic field of the flat coil automatically corrects the long-term change in both the properties of the sensor and the accompanying electronics, thereby increasing the reliability of the integrated circuit of the type in question.

The invention will now be described in further detail based on an embodiment and an accompanying plan showing in FIG. 1 a schematic view of an integrated circuit of the invention with a magnetic sensor in view of the view, FIG. 2 schematically of an integrated circuit of the invention in cross section.

The integrated circuit with the MS magnetic sensor is shown schematically in the top view of FIG. 1 and in cross section in FIG. 2. The magnetic sensor MS in the cross design is otherwise known in the known manner on the silicon substrate S and is provided with voltage connecting strips SU1, SU2 and current connecting strips Sil, SI2. All four connection strips are made in the second metal layer M2, which lies above the first metal layer Ml and is separated from it by the oxide layer. This and other oxide layers for transparency in FIG. 1 and 2 are not shown.

In the first metal layer Ml, a planar coil T is made, the inner sheath of which in the smallest technologically achievable distance D surrounds the active area A of the magnetic sensor MS. The inner coil of the flat coil T is symmetrically over four with respect to the magnetic sensor MS, e.g. in the spaces between the arms of the magnetic sensor MS in the cross-section, the internal terminal contacts KI connected to the SLI terminal strip are installed. The coils of the flat coils T are arranged in the first metal layer Ml such that the minimum technologically achievable distance d is between them. The stated requirements for distances D and d must be met in order to minimize the resistance of the flat coil T. The outer coil of the flat coil T is connected to the SL2 connecting strip via the external terminal contact K2. The connecting straps SLI, SL2 for connecting the flat coil T to the current source are made in another metal layer M2.

To maximize the use of the magnetic field of the planar coil T, the distance Y of the first metal layer Ml from the surface of the substrate S and the depth of the active region A of the magnetic sensor MS are as small as possible. Therefore, the distance X of the first metal layer Ml, ie also the plane of the plane coil T, from the bottom of the active region A is technologically achievable minimum. Typically, the depth of the GS is about three times the distance Y. The planar coil T typically has 5 to 10 sheaths, with the number of sheaths mainly dependent on the magnitude of the magnetic sensor MS.

By connecting the integrated plane coil T to the current source, a reference magnetic field is created around it, which is in the immediate vicinity of the coil plane, and therefore also in the active region A directed perpendicularly to that plane. The magnetic field density in active area A is precisely determined by the parameters of the flat coil T and the permeability of silicon. Therefore, accurate sensitivity self-calibration and also rapid testing of the circuit according to the invention are possible with the circuit of the invention. In the circuit of the invention, the formation of a suitable magnetic field can compensate for the temperature and time variation of the sensitivity of the magnetic sensor and the non-ideality of both the symmetry of the cross-sectional design of the magnetic sensor MS and the voltage of the charge. Within the range of normal supply voltage of a magnetic sensor, the integrated circuit of the invention with a magnetic sensor has the same capacity as other known integrated magnetic sensors.

For

Faculty of Electrical Engineering and Computer Science:

FATENTRA PISARNA

Claims (4)

Patent claims An integrated magnetic sensor (MS) circuit coupled with the other integrated circuit on a silicon substrate (S), characterized in that the planar coil (T) encloses the active region (A) of the magnetic sensor with its inner envelope (MS), made in the first metal layer (Ml) above the substrate (S), that the inner coil of the flat coil (T) is connected to the connecting strip (SLI) symmetrically with respect to the magnetic sensor (MS) of the mounted internal contact pins (KI) ), which is made in the second metal layer (M2), which is made above the first metal layer (Ml), and the outer sheath of the flat coil (T) is connected to the connecting strip (SL2) by the connecting contact (K2). in another metal layer (M2). An integrated circuit according to claim 1, characterized in that the inner sheath of the flat coil (T) is spaced from the active area (A) of the magnetic sensor (MS) by a minimum technologically achievable distance (D). An integrated circuit according to claim 2, characterized in that the first metal layer (Ml) is spaced from the bottom of the active region (A) by a minimum technologically achievable distance (X). An integrated circuit according to claim 3, characterized in that the sheaths of the flat coils (T) are spaced from each other by the minimum technologically achievable distance (d).