COVERING FOR A COMPONENT AND METHOD FOR PRODUCING A COVERING FOR A COMPONENT

Abstract

The invention relates to a covering (1) for an electronic component (e.g. of the MEMS, BAW, or SAW type). The covering comprises at least one layer (5, 6, 7) having a structure (19, 20, 21) with a number of prominences (8, 9, 15) and/or depressions (10, 11, 16). The invention furthermore relates to a method for producing a covering (1) of this type.

Claims

1. A covering for a component, wherein the covering (1) comprises at least one layer (5, 6, 7) having a structure (19, 20, 21, 22) with a number of prominences (8, 9, 15) and/or depressions (10, 11, 16).

2. The covering according to claim 1, in which the structure (19, 20, 21, 22) is designed as a corrugation and/or in a wave shape.

3. The covering according to one of the preceding claims, in which the prominences (8, 9, 15) and/or depressions (10, 11, 16) have an elongated shape.

4. The covering according to one of the preceding claims, in which the structure (19, 20, 21, 22) is designed to increase the mechanical stability.

5. The covering according to one of the preceding claims, which delimits a hollow space (4).

6. The covering according to one of the preceding claims, in which the structure (19) is formed on a bottom side (14) of the covering (1).

7. The covering according to one of claims 1 through 5, in which a bottom side (14) of the covering (1) is free of the structure.

8. The covering according to one of the preceding claims, in which the structure (21) is formed on a top side (13) of the covering (1).

9. The covering according to one of claims 1 through 7, in which the top side (13) is free of the structure.

10. The covering according to one of the preceding claims, having a number of structures (19, 20, 21, 22) that differ in their geometry and/or their orientation.

11. The covering according to one of the preceding claims, comprising a number of layers (5, 6, 7) arranged on top of one another, wherein the structure (19, 20, 21, 22) is formed in at least one of the layers (5, 6, 7).

12. The covering according to one of claim 10 or 11, comprising a bottommost layer (5), at least one middle layer (6), and a topmost layer (7), wherein a bottom side (14) and a top side (13) of the covering (1) are free of the structure (19, 20, 21, 22), and wherein the middle layer (6) has the structure (19, 20, 21, 22).

13. An intermediate product for a component with a covering according to one of the preceding claims, wherein the intermediate product comprises a sacrificial layer and at least one layer (5) of the covering (1), wherein the sacrificial layer adjoins a bottom side (14) of the covering (1) and is provided for at least partial removal, and wherein the sacrificial layer has on a top side at least one structure.

14. A component with a covering according to one of claims 1 through 12 and a component structure that is covered by the covering (1).

15. A method for producing a covering according to one of claims 1 through 12, comprising the steps: Providing a carrier substrate (3), Applying at least one layer (5, 6, 7) onto the carrier substrate (3), wherein the layer (5, 6, 7) comprises a structure with a number of prominences (8, 9, 15) and/or depressions (10, 11, 16).

16. The method according to claim 15, comprising the additional step: Applying an additional layer (5, 6, 7) onto the structured layer (5, 6, 7).

17. The method according to claim 16, wherein the additional layer (6, 7) is applied such that the top side (13, 18) of the additional layer (6, 7) is free of the structure (19).

18. The method according to one of claims 15 through 17, comprising the additional step: Removing the layer applied first.

Description

[0031] In the following, the subject matters described here are explained in more detail using schematic exemplary embodiments that are not true to scale.

[0032] Shown are:

[0033] FIG. 1A in schematic cross section, a first embodiment of a covering,

[0034] FIG. 1B in top view, the covering from FIG. 1A,

[0035] FIGS. 2 through 5 in schematic cross sections, additional embodiments of a covering.

[0036] In the following Figures, the same reference characters preferably refer to functionally or structurally corresponding parts of the various embodiments.

[0037] FIG. 1A shows a covering 1 for a component 2 in a cross section. FIG. 1B shows the covering 1 in a top view. The component 2 is formed as an MEMS, BAW, or SAW component, for example.

[0038] The covering 1 is applied onto a carrier substrate 3 and, with the carrier substrate 3, encloses a hollow space 4. One or more component structures (not depicted) may be arranged in the hollow space 4. For example, these are component structures for a filter and/or duplexer. In particular, the component structures may comprise one or more resonators. However, the component structures may also be of a different type. The covering 1 encapsulates the component structure, for example; in particular, a hermetic encapsulation may exist. The component 2 is provided with the covering 1, for example in package form.

[0039] The covering has a number of layers 5, 6, 7. A bottommost layer 5 directly adjoins the hollow space 4. For example, the bottommost layer comprises a silicon oxide. A middle layer 6 comprises a polymer, for example. A topmost layer 7 forms the outer end of the component. For example, the topmost layer 7 comprises a silicon nitride. The bottommost and topmost layers 5, 7 are relatively hard in comparison to the middle layer 6, for example. For example, the middle layer 6 acts as a support layer.

[0040] At least one of the layers 5, 6, 7 of the cover 1 is provided with a structure 20, 21. The structure 20, 21 serves to increase the stability of the covering 1. In particular, the stability may be increased by a structure 20 of the middle layer 6. The bottommost and/or topmost layer 5, 7 have, for example, structures complementary to the structure 20 of the middle layer 6.

[0041] In the embodiment shown in FIGS. 1A and 1B, the middle layer 6 and the topmost layer 7 respectively have a structure 20, 21 with elongated prominences 8, 9. Analogously, the middle layer 6 and the topmost layer 7 have depressions 10, 11 that are formed between the prominences 8, 9. The middle layer 6 has the structure 20 on its top side 18. The bottom side 17 of the middle layer 6 has no structure.

[0042] The prominences 9 in the topmost layer 7 form prominences on the top side 13 of the covering 1. The top side 13 of the covering 1 corresponds to the top side of the topmost layer 7.

[0043] The prominences 8, 9 are arranged regularly and have a uniform geometry. In particular, the lengths 1 and the widths b of the prominences 8, 9 are similar or identical. The prominences 8, 9 extend along a common direction 12. Due to the prominences 8, 9, the middle and upper layer 6, 7 receive a wavy structure.

[0044] The prominences 8, 9 lead to an increase in the mechanical stability of the covering 1 in a similar way as in a corrugated sheet roof of a building or in a corrugated board. This allows for the thickness of the covering 1 to be kept low with sufficient stability. In particular, coverings 1 formed with a large footprint may also be used without the thickness of the covering 1 needing to be increased. For example, this allows for an entire filter and/or duplexer unit to be provided with a single, large covering, instead of providing individual parts, for example one or more resonators, with a number of separate coverings.

[0045] For example, the component structure and/or component arrangement that is to be covered has an elongated shape in top view. In this case, for example, the prominences 8, 9 extend orthogonally to the longitudinal direction of the component arrangement. The prominences 8, 9 may also not have an elongated shape. For example, the structure is formed as in an egg carton. For example, this is advantageous given a component structure or component arrangement that has no long side, for example is of a quadratic design.

[0046] For example, the prominences 8, 9 extend nearly across the entire surface of the covering 1. In another embodiment, the covering 1 may be provided with the prominences 8, 9 only on a portion of its surface.

[0047] The bottommost layer 5 is free of prominences. In particular, the bottom side 14 of the covering that is formed by the side of the bottommost layer 5 that faces the hollow space 4 has a smooth surface. In particular, the bottom side 14 has no prominences or depressions. The prominences 8, 9 thus do not affect the shape of the hollow space 4.

[0048] The covering 1 is preferably produced in a thin-film technology. For example, to form the covering 1, a sacrificial layer is first applied onto the carrier substrate 3. In the depicted embodiment, the sacrificial layer has a smooth top side.

[0049] The bottommost layer 5 is applied onto the sacrificial layer. For example, the sacrificial layer is subsequently entirely or partially removed. To remove the sacrificial layer, an opening may be formed in the bottommost layer 5. The middle layer 6 is applied onto the bottommost layer 5. The opening in the bottommost layer 5 may be sealed by the middle layer 6. The middle layer 6 is applied by means of a lithographic process, for example, and is thereby structured. For example, a greyscale mask is used. The greyscale mask may in this case have very fine holes that are not dissolved. Depending on the formation of the holes, the structure 20 may have more or less steep sides.

[0050] Finally, the topmost layer 7 is applied onto the middle layer 6. The topmost layer 7 receives its structure 21 via the structure 20 of the middle layer 6 such that a complementary structure 21 is formed.

[0051] FIG. 2 shows an additional embodiment of a covering 1. Here as well, the covering 1 comprises three layers 5, 6, 7. However, in contrast to the embodiment from FIG. 1A, the structure 20 is not externally visible here.

[0052] The middle layer 6 has on its top side 18 a structure 20 with prominences 8 or depressions 10. The structure 20 is formed in a zigzag shape. The bottom side of the topmost layer 6 is formed complementarily to the top side 18, meaning that it likewise has a zigzag-shaped structure.

[0053] The top side 13 of the covering 1 that is formed by the top side of the topmost layer 7 is formed smoothly. In particular, no prominences or depressions are present on the top side 13. For example, the topmost layer 7 is applied such that the depressions in the middle layer 6 are completely filled with the material of the topmost layer 7. The topmost layer 7 may additionally be externally smoothed.

[0054] A combination of features of the coverings from FIGS. 1A and 2 is also possible. For example, a wavy structure may be present in one or more layers 5, 6, 7 of the covering 1 according to FIG. 1A, wherein the top side 13 of the covering 1 is formed smoothly as in FIG. 2. On the other hand, a zigzag structure 20 according to FIG. 2 may also be present, and a complementary structure 21 may be formed on the top side 13. The structure 20 may also be of zigzag shape in the middle layer 6 and transition into a wavy structure 21 on the top side 13.

[0055] FIG. 3 shows an additional embodiment of a covering 1. Here as well, the top side 13 and bottom side 14 of the covering 1 are formed smoothly. The embodiment differs from the embodiment from FIG. 2 in the shape of the structure of the middle layer 6.

[0056] The middle layer 6 has elongated prominences 8 with a trapezoidal cross section. The base of the trapezoid is longer than the side opposite it. In another embodiment, the base may also be shorter than or of the same length as the opposite side.

[0057] Depressions 10 are formed between the prominences 8. The depressions 10 form clearances in the middle layer 6 and extend to the bottommost layer 5. The prominences 9 of the middle layer 6 are thus not connected with one another. The depressions 10 are completely filled by the material of the topmost layer 7.

[0058] FIG. 4 shows an additional embodiment of a covering 1. In contrast to the embodiments shown in FIGS. 1A through 3, the bottom side 14 of the covering has a structure 19. In particular, prominences 15 and depressions 16 are present on the bottom side 14. The structure 19 is of wavy shape. However, a different shape of the structure may also be present. The structure 19 on the bottom side 14 is generated by a sacrificial layer structured on the top side, for example. The bottommost layer 5 thus receives a complementary structure 19. The middle layer likewise receives complementary structures 22, 20 on its bottom side 17 and its top side 18. The top side 13 of the covering 1 is likewise structured in a complementary manner, in particular in a wave shape.

[0059] FIG. 5 shows an additional embodiment of a covering 1 in which a structure 19 is present on the bottom side 14 of the covering 1. In contrast to FIG. 4, the top side 13 of the covering 1 is formed smoothly.

[0060] The middle layer 6 has a structure 22 only on its bottom side 17. The top side 18 of the middle layer 6 is formed smoothly. The geometry of the topmost layer 7 is complementary to the geometry of the top side 18 of the middle layer 6. In particular, the topmost layer 7 has no structure and thus is formed smoothly on its top side and the bottom side. The geometry of the top side 13 of the covering is thus complementary to the geometry of the top side 18 of the middle layer 6.

[0061] In another embodiment, the top side 18 of the middle layer 6 may likewise have a structure analogously to the embodiments of FIGS. 2 and 3. The topmost layer 7 may completely fill the depressions and have a smooth top side such that the top side 13 of the covering 1 is formed smoothly.

[0062] In a further embodiment, various layers 5, 6, 7 of the covering may have different structures. For example, the bottommost layer 5 has on its bottom side 14 a structure 19 in which elongated prominences extend in a first direction. For example, the topmost layer 7 has on its top side 13 a structure 21 in which elongated prominences extend in a second direction that does not coincide with the first direction. For example, the second direction extends orthogonally to the first direction.

Reference Character List

[0063] 1 covering [0064] 2 component [0065] 3 substrate [0066] 4 hollow space [0067] 5 bottommost layer [0068] 6 middle layer [0069] 7 topmost layer [0070] 8 prominence [0071] 9 prominence [0072] 10 depression [0073] 11 depression [0074] 12 direction [0075] 13 top side of the covering [0076] 14 bottom side of the covering [0077] 15 prominence [0078] 16 depression [0079] 17 bottom side of the middle layer [0080] 18 top side of the middle layer [0081] 19 structure on the bottom side of the covering [0082] 20 structure on the top side of the middle layer [0083] 21 structure on the top side of the covering [0084] 22 structure on the bottom side of the middle layer [0085] b width of the prominence [0086] l length of the prominence