COMPONENT WITH REDUCED STRESS FORCES IN THE SUBSTRATE

Abstract

A component with a magnetic field sensor. The electronic component is located in a semiconductor substrate or on the surface of the semiconductor substrate and is surrounded at least partially, preferably largely, by a trench in the semiconductor substrate. The trench is filled with a filling material.

Claims

1. A component comprising: a semiconductor substrate with a surface; a magnetic field sensor; and a trench filled with a filling material in the semiconductor substrate, said trench surrounding the magnetic field sensor at least partially, wherein the filling material is a buffer material for absorbing mechanical stresses.

2. The component according to claim 1, wherein the surface has a buffer layer.

3. The component according to claim 1, wherein the trench and the magnetic field sensor are covered with a cap.

4. The component according to claim 1, wherein the trench surrounds the magnetic field sensor largely, in order to form an island, and further has a connecting bridge.

5. The component according to claim 4, further comprising conductor paths, diffusions or bonding connections, which contact the electronic connections of the magnetic field sensor and are guided over the connecting bridge.

6. The component according to claim 1, wherein the magnetic field sensor is integrated in the semiconductor substrate.

7. The component according to claim 1, wherein the magnetic field sensor is a Hall sensor.

8. The component according to claim 1, wherein the trench has a depth which is at least 5 μm or one twentieth of the diagonal of the magnetic field sensor.

9. The component according to claim 1, wherein the trench penetrates the semiconductor substrate fully.

10. The component according to claim 1, wherein the width of the trench is less than 100 μm.

11. The component according to claim 1, wherein the filling material is a polymer or polyimide.

12. The component according to claim 1, wherein the surface of the trench has an encapsulation layer.

13. The component according to claim 12, wherein the encapsulation layer is a nitride.

14. The component according to claim 1, wherein the trench is produced by laser removal.

15. A construction element with a component comprising a semiconductor substrate with a surface; a magnetic field sensor; and a trench filled with a filling material in the semiconductor substrate, said trench surrounding the magnetic field sensor at least partially, comprising a further component that is surrounded at least partially by the trench, wherein the filling material is a buffer material for absorbing mechanical stresses.

16. The construction element according to claim 15, wherein the further component is a circuitry component for controlling the magnetic field sensor.

17. The construction element according to claim 15, wherein the further component is a circuitry component for capturing the data from the magnetic field sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description and the accompanying drawings, in which:

[0028] FIG. 1 shows a side view of the component.

[0029] FIG. 1B shows a plan view of the component.

[0030] FIG. 1C shows the side view with filled trench.

[0031] FIG. 1D shows the side view of a component with a lid.

[0032] FIGS. 2A-2B and FIGS. 2D-2N and FIG. 2P show several construction components with differently arranged connecting bridges.

[0033] FIG. 3 shows a lateral Hall sensor according to the state of the art.

DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 1A shows a side view of a component 10 according to one aspect of this invention. A magnetic field sensor 30 is introduced or integrated into a semiconductor substrate 20 or arranged on a surface 25 of the semiconductor substrate 20.

[0035] The magnetic field sensor 30 is surrounded at least partially by a trench 40. As can be seen in FIG. 1b, the trench 40 in this aspect of the disclosure surrounds the electronic component 30 largely, but not completely, forming a kind of “island” 35 in the semiconductor substrate 20.

[0036] A connecting bridge 50 passes between the island portion of the surface 25 and the other part of the semiconductor substrate 20. Metal conductor paths 60 extend via the connecting bridge 50 which connect the magnetic field sensor 30 on the island 35 with further metal conductor paths on the remaining part of the surface 25. A Hall sensor requires, for example, at least four lines 60 for the four connectors or electronic connections. The electrical connections can be implemented also by means of suitable diffusions on the connecting bridge instead of metal conductor paths.

[0037] The trench 40 has a depth t.sub.t, which should be at least 5 μm, or one twentieth of the diagonal H.sub.d of the island 35 on the surface 25. The trench 40 can also penetrate the semiconductor substrate 20 fully. The trench 40 around the island 35 results in the magnetic field sensor 30 being largely isolated from stress forces in the semiconductor substrate 20. The magnetic field sensor 30 on the island 35 is thus not influenced by the stress forces in the semiconductor substrate 20.

[0038] As can be seen from FIGS. 2A-2B and FIGS. 2C-2N and FIG. 2P, the connecting bridge 60 is not required to run centrally on one side of the island in the trench 40. The connecting bridge 50 can also be arranged on the side, as can be seen from FIG. 2B. Two connecting bridges 50 can be present likewise (see FIG. 2D). In some other embodiments, the trench 40 is not required to fully surround the island 35 to achieve the desired isolation of the stress forces or to prevent the spreading of the same. FIG. 2E-2H show aspects of the structure, for example, in which the trench 40 does not fully surround the island 35. Although the mechanical isolation in the aspects according to 2E-H is not as strong as in other aspects, the manufacture of such trenches 40 can be achieved more cost-effectively, and the island 35 is connected to the remaining semiconductor substrate 20 in a mechanically more robust fashion.

[0039] FIG. 2I-2M show other embodiments of the trench 40, wherein in FIG. 2M the trench 40 is formed without a connecting bridge 50. The contacting of the electronic component can be established in this case by bonding connections for example. Furthermore, it is possible that the magnetic field sensor 30 can contain not only one single electronic component on its surface 25, but also have additional components 70. FIG. 2L shows a different form of the trench 40 with a further component 70. FIG. 2P shows a possible embodiment with an island 35 on the edge of the semiconductor substrate 20 and FIG. 2N shows a possible embodiment with an island in a corner of the semiconductor substrate 20.

[0040] The trench 40 is obtained by a conventional etching process, for example by laser removal or other physical or wet-chemical etching. As other etching processes dry etching processes (reactive ion etching—RIE, deep reactive ion etching—Bosch process, DRIE and ion beam cutting), or wet-chemical etching by means of KOH or EDP can be considered. The magnetic field sensor 30 and the other components are manufactured by conventional production steps.

[0041] The trench 40 in FIG. 1C is optionally lined partially on its inner surface (passivated) with one or several components for protection against environmental influences. As a lining layer 42, a nitride such as Si.sub.3N.sub.4 or a polyimide is preferably used. The trench 40 is completely filled, with or without lining, wherein the filling of the trench can also be effected with several layers of different buffer materials. The buffer material/the buffer materials 45 has/have typically a smaller elasticity and/or bulk modulus than the substrate. As the buffer material, preferably a polymer is used, for example an elastomer such as a silicon compound or other suitable material, which can absorb the mechanical stresses that occur in the filled trench. However, the buffer material can also be an epoxy resin. The filling of the trench 40 allows a further encapsulation of the component, wherein no, or only small mechanical stresses are transferred from the substrate to the island via the filling material 45.

[0042] A further buffer layer 46 can be applied to the surface 25 of the semiconductor substrate and the filled trench 40. This buffer layer absorbs the mechanical stresses acting from the sealing compound on the surface of the island. The buffer layer typically covers at least the island as well as the trench and thus covers the entire Si surface only partially. In one aspect, the buffer layer consists of the same material with which the trenches are filled. Alternatively, the buffer layer 46 from a plastic foil can be applied by adhesive bonding on the surface 25. (FIG. 1C shows a trench 40 with encapsulation layer 42 and buffer filling material 45 and buffer layer 46.)

[0043] FIG. 1D shows a component with a cap 80 which is attached over the island by means of an adhesive layer 81. The cap 80 encloses an air volume 82 in its cavity. The cap protects the trench against the intrusion of material during the encapsulation process and against the intrusion of moisture and the formation of water reservoirs in the trench. Alternatively, the cap 80 can also be applied to a component with a filled trench with/without buffer layer over the island surface. The cap 80 is typically manufactured of a non-magnetic material. When a non-magnetic and electroconductive material is used, such as copper, for example, the sensor element is additionally shielded from electromagnetic radiation.

[0044] Moreover, in addition to the magnetic field sensor 30, the component 10 can also have several magnetic field sensors and include circuitry components that have a cross-sensitivity to mechanical stresses and are required for the signal processing of the magnetic field sensor/sensors, such as, for example, analog to digital converter, or voltage and current sources for supplying the sensor.

[0045] The foregoing description of the preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents. The entirety of each of the aforementioned documents is incorporated by reference herein.