MEMS component having MEMS element with chamber and ASIC component

Abstract

The invention relates to a MEMS component having a MEMS element with a chamber, the chamber being at least partially delimited by an ASIC component, the ASIC component having a plurality of conductor track layers which lie one above the other in the y-direction between a cover layer and a bottom layer, the conductor track layers being connected to circuit elements of the ASIC component and / or sensor elements and / or actuator elements of the MEMS element, the ASIC component is adjacent to the chamber via the cover layer, the conductor track layers comprise at least one first conductor track layer and at least one second conductor track layer, the first conductor track layer is arranged between the second conductor track layer and the cover layer, the first conductor track layer comprises at least one first conductor track, and the second conductor track layer comprises at least one second conductor track. The first conductor path has a layer stack consisting of an aluminum layer and a titanium layer arranged one above the other in the y-direction, the titanium layer being arranged between the second conductor path layer and the aluminum layer, the titanium layer having a thickness in the y-direction greater than 40 nm, the second conductor path layer having a copper-containing second conductor path, the thickness of the titanium layer being greater than 40 nm, and the thickness of the aluminum layer being greater than 40 nm. The titanium layer is provided as a getter layer for bonding hydrogen, the hydrogen being releasable from the copper layer of the second conductor track, in particular from the stack of copper-based conductor track layers, and the titanium layer reducing or preventing the entry of the released hydrogen into the chamber.

Description

Technical Field

[0001] The present invention relates to a MEMS component having a cavity-like MEMS element, wherein the cavity is at least partially bounded by an ASIC component. Background Technology

[0002] According to DE 10 2004 020 685 B3, a MEMS component with a cavity is provided in which an air-absorbing layer is provided in the cavity for adsorbing specific gas molecules. Summary of the Invention

[0003] The object of the present invention is to design a MEMS component having a cavity, wherein the ASIC component at least partially confines the cavity, thereby reducing, and in particular avoiding, pressure changes in the cavity caused by gas diffusion from the ASIC component.

[0004] The objective of this invention is achieved by the MEMS component according to the invention.

[0005] Advantageous embodiments of the present invention are described below.

[0006] The advantage of the proposed MEMS component is that it can reduce, and in particular avoid, the release of hydrogen gas from the ASIC component into the chamber of the MEMS element.

[0007] This is achieved by the following: the ASIC component has a printed conductor with a titanium layer disposed between the chamber and another printed conductor. The thickness of the titanium layer is preferably greater than 40 nanometers. A second printed conductor system (i.e., printed conductor and insulating layer) has copper, or the second printed conductor is made of copper, or the second printed conductor is constructed as a copper printed conductor, wherein hydrogen can be released from the copper. Furthermore, the ASIC component may have a stack of multiple copper printed conductors from which hydrogen can be released. Hydrogen released from the copper printed conductors and diffused toward the chamber is at least partially, and especially completely, bound by the titanium layer. Thus, the titanium layer constitutes an getter layer for binding hydrogen. Depending on the chosen embodiment, the titanium layer may also have a greater thickness to adequately bind hydrogen from the second printed conductor.

[0008] Titanium in the titanium layer has the property of forming hydrides, wherein hydrogen gas is embedded in the titanium layer upon energy release. The thickness and / or width of the titanium layer can be adjusted according to the desired amount of hydrogen gas. Preferably, the titanium content should be sufficient to bind all the hydrogen gas released from at least one second printed conductor or copper printed conductor stack.

[0009] The ASIC component is adjacent to the cavity of the MEMS element through a cover layer. Sensor elements and / or actuator elements may be arranged adjacent to the cavity or arranged in the cavity, or connected to the cavity through conduits.

[0010] The ASIC component has multiple stacked printed conductor layers between a cover layer and a bottom layer. The printed conductors of the printed conductor layers can be connected to circuit elements of the ASIC component and / or sensor elements and / or actuator elements of a MEMS component. The ASIC component has a first printed conductor layer disposed between a cover layer and a second printed conductor layer. The first printed conductor layer has at least one first printed conductor, wherein the first printed conductor has a layer stack consisting of at least one aluminum layer and a titanium layer. The titanium layer is disposed between the aluminum layer and the second printed conductor layer, thus facing the second printed conductor layer. The second printed conductor layer has a copper-containing second printed conductor, or is constructed as a copper layer. Therefore, the titanium layer acts as a getter layer to trap hydrogen gas released from the copper printed conductor stack of the second printed conductor and diffuses towards the chamber. In this way, the intrusion of released hydrogen gas into the chamber is reduced or prevented.

[0011] In one embodiment, the titanium layer has a base surface in a first xz plane, wherein the second printed conductor has a base surface in a second xz plane. In a vertical projection along the y-direction, the base surface of the titanium layer is disposed above the second printed conductor for at least 50% of its length, and particularly covers the entire width of the second printed conductor. Therefore, in a vertical projection along the y-direction, the titanium layer of the first printed conductor preferably covers the entire width of the second printed conductor for at least 50% of its length. In this way, the titanium layer of the first printed conductor achieves coverage of the second printed conductor, making the titanium layer highly efficient as a getter layer.

[0012] According to the selected embodiment, in the vertical projection, the titanium layer covers more than 50%, particularly more than 70%, and especially more than 90% of the length of the second printed conductor. Preferably, the titanium layer covers the entire width of the second printed conductor, particularly exceeding the width of the second printed conductor by at least 5%, especially 10%, on each side. The wider the range of the titanium layer covering the width of the second printed conductor in the vertical projection, the better the titanium layer acts as a getter layer.

[0013] In another embodiment, in addition to the second printed conductor, the second printed conductor layer also has another second printed conductor, which is also made of copper or constructed as a copper layer. The second printed conductor and the other second printed conductor are arranged spaced apart from each other in the lateral direction through an intermediate region. In a vertical projection along the y-direction, the base surface of the titanium layer is constructed such that the base surface of the titanium layer covers the base surface of the second printed conductor, the intermediate region between the second printed conductor and the other second printed conductor, and the base surface of the other second printed conductor. In this way, by covering not only the second printed conductor and the other second printed conductor, but also the intermediate region between the two second printed conductors, hydrogen gas is prevented from being released into the chamber. In this way, the effect of the titanium layer as a getter layer is improved.

[0014] In another embodiment, a barrier layer is provided between the chamber and the first printed conductor layer. This barrier layer is configured to reduce, and in particular prevent, the release of argon gas from the first printed conductor layer into the chamber. For example, the barrier layer has a silicon nitride layer, wherein the silicon nitride layer has a thickness of at least 40 nanometers, and is configured, for example, as a sputtered layer. The barrier layer reduces, and in particular prevents, the release of argon gas into the chamber.

[0015] In another embodiment, the MEMS component has a through-hole contact wire that leads to a titanium layer of a first printed conductor. In the region of the through-hole contact wire, the thickness of the titanium layer in the y-direction is reduced relative to the thickness of the laterally adjacent region in the xz plane. This reduces the resistance between the through-hole contact wire and the aluminum layer. This reduced thickness is achieved, in particular, through grooves in the titanium layer in which the through-hole contact wire is guided. In this way, even if the titanium layer has a substantially large thickness, the ohmic resistance of the conductive connection between the through-hole contact wire and the aluminum layer can be reduced. The aluminum layer is configured to guide most of the current to the first printed conductor.

[0016] In one embodiment, the through-hole contact wire has tungsten, and is particularly made of tungsten. Tungsten is suitable for achieving a reliable and low-resistance construction of the through-hole contact wire.

[0017] Depending on the selected implementation, the thickness of the titanium layer in the y-direction can be greater than 100 nanometers, particularly greater than 150 nanometers or greater than 180 nanometers. The greater the thickness of the titanium layer, the more titanium is available for the hydrogen-binding and absorption function.

[0018] In another embodiment, an additional titanium layer is disposed between the aluminum layer of the first printed conductor layer and the cover layer, wherein the thickness of the additional titanium layer is less than 20 nanometers, and particularly less than 15 nanometers. This additional titanium layer serves more for the reliable structure of the first printed conductor and less as a getter layer.

[0019] In another embodiment, the ASIC component has an additional first printed conductor layer between the first and second printed conductor layers, wherein the additional first printed conductor layer has at least additional first printed conductors, wherein the additional first printed conductors have a layer stack consisting of an aluminum layer and a titanium layer. The aluminum layer is disposed on the titanium layer of the additional first printed conductor layer and is located between the titanium layer of the additional first printed conductor layer and the first printed conductor layer. The titanium layer of the additional first printed conductor layer has a thickness greater than 40 nanometers and serves as a getter layer to trap hydrogen gas that can be released from at least one or more copper-containing second printed conductors, particularly from a layer stack comprising multiple second printed conductor layers. In this way, the intrusion of released hydrogen gas into the chamber can also be reduced or prevented.

[0020] Another advantage of the proposed MEMS component is its ability to withstand continuous temperature stress processes, such as those occurring during standard welding, encapsulation, or high-temperature storage, without significantly affecting its electrical performance. In this way, the internal pressure of the chamber can be reliably maintained over a long period.

[0021] MEMS components include MEMS (Micro-Electro-Mechanical Systems) elements with micromechanical structures and chambers, and ASIC (Application-Specific Integrated Circuit) components with circuit assemblies that work in conjunction with the micromechanical structures of the MEMS elements. The MEMS elements are mounted on the ASIC components such that the micromechanical structures of the MEMS elements are arranged within the chamber between the MEMS elements and the ASIC components. Attached Figure Description

[0022] The following will describe in detail the embodiments of the MEMS components with reference to the accompanying drawings. The drawings are as follows: Figure 1 Schematic cross-sectional view of a MEMS component with chambered MEMS elements and ASIC components; Figure 2 A schematic top view of an ASIC component; Figure 3 : A more detailed schematic cross-sectional view of the ASIC component; Figure 4 A schematic top view of the first printed conductor of an ASIC component; Figure 5 : A schematic cross-sectional view of another implementation of an ASIC component; Figure 6 A schematic partial cross-sectional view of the through-hole contact wires of an ASIC component; Figure 7 : A schematic cross-sectional view of another implementation of an ASIC component. Detailed Implementation

[0023] Figure 1 A schematic cross-sectional view of a MEMS component 1 is shown, which has a MEMS element 2 and an ASIC component 3. A chamber 4 is constructed between the MEMS element 2 and the ASIC component 3. The chamber 4 is defined by the MEMS element 2 and at least partially by the ASIC component 3. Sensor elements and / or actuator elements 5 of the MEMS element 2 may be arranged adjacent to or within the chamber 4, or at least communicate with the chamber 4 via channels. The ASIC component 3 has a cover layer 6 that is at least partially directly adjacent to the chamber 4.

[0024] Figure 2 A schematic view of the ASIC component 3 is shown, in which the chamber 4 is schematically indicated by dashed lines. In the illustrated embodiment, the chamber 4 is bounded by the MEMS element 2 on five sides and by the ASIC component 3 on one side.

[0025] Figure 3 A partial cross-sectional view of the ASIC component 3 is shown schematically, wherein the ASIC component 3 has a first printed conductor layer 8 adjacent to the cover layer 6. A second printed conductor layer 9 is bonded to the first printed conductor layer 8 along the y-direction. A bottom layer 7 is bonded to the second printed conductor layer 9. Electrical and / or electronic circuitry of the ASIC component may be integrated in the bottom layer 7.

[0026] The first printed conductor layer 8 has a first insulating layer 10, and a first printed conductor 11 is embedded in the first insulating layer. Adjacent to the second printed conductor layer 9, the first printed conductor 11 has a first layer 12, which is made of titanium or titanium. Depending on the chosen embodiment, the first layer 12 may also be a stack of layers consisting of a sequence of titanium nitride, titanium, and titanium nitride, or have such a stack. A first conductive layer 13, which is made of aluminum or aluminum, is disposed on the first conductive layer 12. A first capping layer 14, which is made of titanium and particularly consists of a stack of layers consisting of a sequence of titanium nitride, titanium, and titanium nitride, may be disposed on the first conductive layer 13.

[0027] The first titanium layer 12 can have a thickness between 40 nanometers and 200 nanometers, or even thicker. The first titanium layer 12 constitutes an getter layer for hydrogen diffusion. The first titanium nitride layer can have a thickness of less than 10 nanometers and, for example, acts as an adhesive or barrier layer to prevent material mixing.

[0028] The second printed conductor layer 9 has a second insulating layer 15, and a second printed conductor 16 is embedded in the second insulating layer. The second printed conductor is made of copper or is made of copper. The second printed conductor 16 and the second insulating layer 15 are disposed above the bottom layer 7.

[0029] The width of the first layer 12 in the x-direction is greater than the width of the second printed conductor 16. Furthermore, the first layer 12 is arranged between the chamber 4 and the second printed conductor 16 such that, in its projection along the y-direction, the first layer 12 covers the entire width of the second printed conductor 16. Preferably, the titanium layer of the first layer 12 extends laterally beyond the second printed conductor 16 from both sides in the x-direction. This arrangement achieves good gas absorption and prevents hydrogen from diffusing into the chamber 4.

[0030] Furthermore, the ASIC component 3 can be configured such that a plurality of first printed conductors 11 are arranged side-by-side in the first printed conductor layer 8. Furthermore, the ASIC component 3 can be configured such that a plurality of second printed conductors 16 are arranged side-by-side in the second printed conductor layer 9. The structures of the first printed conductors 11 can be identical or different. Similarly, the second printed conductors 16 can be constructed identically or structurally different from each other.

[0031] The capping layer 6 may constitute a barrier layer or have a barrier layer that reduces, in particular prevents, the release of a carrier gas, such as argon, from the first printed conductor layer into the chamber. For example, the capping layer 6 may serve as a barrier layer having a silicon nitride layer. The silicon nitride layer may, in particular, have a thickness of, for example, 50 nanometers to 100 nanometers along the y-direction. The barrier layer, particularly the silicon nitride layer, may be configured as a sputtering layer.

[0032] Figure 4 A schematic diagram shows a top view of the titanium layer 12, in which the second printed conductor 16 below is indicated by a dashed line. The first printed conductor 11, or the first layer 12, extends along the z-direction in the length direction, and the second printed conductor 16 also extends along the z-direction in the length direction.

[0033] The titanium layer of the first layer 12 extends laterally in the x-direction, that is, along the x-direction beyond the second printed conductor 16 by at least a predetermined distance x1, x2. The predetermined distances x1, x2 can be 1% to 5% of the width of the second printed conductor 16 in the x-direction, or even greater. The greater the distance the first printed conductor 11 extends outward from both sides of the second printed conductor 16 in the x-direction, the better the shielding effect in preventing hydrogen from diffusing into the chamber.

[0034] Figure 5 A schematic cross-sectional view of another embodiment of the ASIC component 3 is shown. In this embodiment, the second printed conductor layer 9 has additional second printed conductors 17, which are laterally spaced from the second printed conductor 16 in the x-direction via an intermediate region 18. The additional second printed conductors 17 are also made of copper or copper. In this embodiment, with... Figure 3Similar to the embodiment shown, the first printed conductor 11 is constructed with a titanium layer of a first layer 12, a first conductive layer 13, and a first capping layer 14. However, in projection along the y-direction, this first printed conductor covers the second printed conductor 16, the intermediate region 18 between the second printed conductor 16 and another second printed conductor 17, and the other second printed conductor 17. Furthermore, the first layer 12 of the first printed conductor 11 extends laterally along the x-direction beyond the second printed conductor 16 and the other second printed conductor 17. In this way, the titanium layer of the first layer 12 covers not only the second printed conductor 16 and the other second printed conductor 17 in the direction towards the chamber, but also the intermediate region 18 between the second printed conductor 16 and the other second printed conductor 17. In this way, improved protection is achieved to prevent hydrogen from diffusing into the chamber 4.

[0035] Figure 6 A schematic partial cross-sectional view of the ASIC component 3 is shown, in which conductive through-hole contact wires 20 extend from the bottom layer 7, through the second insulating layer 15 of the second printed conductor layer 9, and to the first conductive layer 13 for electrical contact connection. To reduce the resistance of the first layer 12, which has titanium, the first layer 12 has a groove 19 filled with printed conductor material 11. Therefore, the remaining thickness 21 of the first layer 12 constructed between the end of the through-hole contact wire 20 and the first conductive layer 13 is significantly reduced, for example, to 5% to 30% of the thickness of the titanium layer of the first layer 12.

[0036] Depending on the selected implementation, the through-hole contact wire 20 may have tungsten or be made of tungsten.

[0037] Figure 7 Another embodiment of the ASIC component 3 is shown in cross-sectional and schematic diagrams. In this embodiment, the cover layer 6 has a cover insulating layer 25 and a barrier layer 26. The first printed conductor layer 8 has a bottom insulating layer 27 on which the first printed conductor 11 and the first insulating layer 10 are disposed.

[0038] Furthermore, an additional first printed conductor layer 22 is arranged adjacent to the first printed conductor layer 8. This additional first printed conductor layer also has a first insulating layer 10, a bottom insulating layer 27, and additional first printed conductors 30. The printed conductors 11 of the first printed conductor layer 8 and the additional first printed conductors 30 of the additional first printed conductor layer 22 may have the same layer structure, particularly having a titanium-containing first layer 12 and an aluminum-containing first conductive layer 13, such as... Figure 3 As stated above.

[0039] Another first printed conductor layer 22 is disposed above the second printed conductor layer 9. In the illustrated embodiment, the second printed conductor layer 9 has a second bottom insulating layer 28, a second insulating layer 15, and a plurality of second printed conductors 16. In the illustrated embodiment, additional second printed conductor layers 23, 24, and 25 are also disposed, which are similar in construction to the second printed conductor layer 9. The second printed conductor layer 9 and the additional second printed conductor layers 23, 24, and 25 may have the same structure, and in particular may have copper-containing second printed conductors 16.

[0040] The advantage of the second printed conductor layers 9, 23, 24, and 25 is that they achieve high wiring density with low parasitic wiring capacitance. High wiring density in narrow printed conductors significantly improves the so-called utilization of digital gates. Therefore, high area efficiency can be achieved.

[0041] The advantage of the first printed conductor layers 8 and 22 is that a relatively thick titanium layer, i.e., the first layer 12, provides a high-performance getter layer for trapping hydrogen released from the underlying copper printed conductors. Even if hydrogen is embedded in the titanium, the electrical properties of the titanium remain almost unchanged. Preferably, the thickness of the first layer 12 is adjusted according to the expected amount of hydrogen. In the MEMS component proposed in this invention, the titanium layer is applied as a single layer, thus eliminating the need for additional masks or additional process steps.

[0042] Preferably, when viewed from the projection along the y-direction, the first layer 12 of the first printed conductor layer 8 covers as much of the surface of the second printed conductor 16 of the second printed conductor layer 9 as possible.

[0043] The tungsten-tungsten through-hole contact wires used prevent copper from entering the aluminum material of the first conductive layer 13.

[0044] In addition, the use of a solid tungsten frame can reduce or eliminate cratering during wafer bonding.

[0045] The MEMS components proposed in this invention enable the optimization of layer structures, thereby reducing hydrogen release and achieving high wiring density in ASIC components.

[0046] The aluminum layer of the first conductive layer 13 can have a thickness in the range of 250 to 350 nanometers, or even up to 1 micrometer or more.

[0047] The insulating layer can be, for example, an oxide layer, especially a silicon oxide layer or a silicon nitride layer.

[0048] The width of the second printed conductor 16, which has copper or is made of copper, can be less than 100 nanometers or larger. The widths of the first layer 12 and the first conductive layer 13 can be 150 nanometers or wider.

Claims

1. A MEMS component (1) having a MEMS element (2) with a cavity (4), wherein, The chamber (4) is at least partially defined by an ASIC component (3), wherein the ASIC component (3) has a plurality of printed conductor layers (8, 9) stacked in the y-direction between a cover layer (6) and a bottom layer (7), wherein the printed conductor layers (8, 9) are connected to circuit elements of the ASIC component and / or sensor elements and / or actuator elements of the MEMS component, wherein the ASIC component (3) is adjacent to the chamber (4) through the cover layer (6), wherein the printed conductor layers (8, 9) have at least one first printed conductor layer (8) and at least one second printed conductor layer (9), wherein the first printed conductor layer (8) is arranged on the second printed conductor layer (9) and the cover layer (7). Between layers (6), wherein the first printed conductor layer (8) has at least one first printed conductor (11), wherein the first printed conductor (11) has a layer stack consisting of an aluminum layer and a titanium layer (12) stacked in the y direction, wherein the titanium layer (12) is disposed between the second printed conductor layer (9) and the aluminum layer (13), wherein the titanium layer (12) has a thickness greater than 40 nanometers in the y direction, wherein the second printed conductor layer (9) has a second printed conductor (16) containing copper, wherein the titanium layer (12) is configured as an absorbent layer for binding hydrogen, wherein hydrogen can be released from the copper layer, wherein the titanium layer (12) reduces or prevents the released hydrogen from entering the chamber (4).

2. The MEMS component according to claim 1, wherein, The titanium layer (12) of the first printed conductor (11) has a base surface in a first xz plane, wherein the second printed conductor (16) has a base surface in a second xz plane, wherein, in a vertical projection along the y direction, the base surface of the titanium layer (12) covers the base surface of the second printed conductor (16) over at least 50% of the length of the second printed conductor (16) and over the entire width of the second printed conductor (16).

3. The MEMS component according to any of the preceding claims, wherein, The second printed conductor layer (9) has an additional second printed conductor (17) in addition to the second printed conductor (16), wherein the additional second printed conductor (17) is made of copper, wherein the second printed conductor (16) and the additional second printed conductor (17) are arranged laterally spaced apart by an intermediate region (18), wherein, in a vertical projection along the y-direction, the base surface of the titanium layer (12) extends on the base surface of the second printed conductor (16), the intermediate region (18) and the base surface of the additional second printed conductor (17), such that the intermediate region (18) between the two second printed conductors (16, 17) is also covered to prevent hydrogen from being released toward the chamber (4).

4. The MEMS component according to any of the preceding claims, wherein, A barrier layer (26) is provided between the chamber (4) and the first printed conductor layer (8), the barrier layer reducing, in particular preventing, the release of argon gas from the first printed conductor layer into the chamber.

5. The MEMS component according to claim 4, wherein, The barrier layer (26) has a silicon nitride layer, wherein the silicon nitride layer may have a thickness of at least 40 nanometers and be configured as a sputtered layer.

6. The MEMS component according to any of the preceding claims, wherein, Through-hole contact wires (20) are guided to the titanium layer (12), wherein, in the region of the through-hole contact wires, the titanium layer (12) has a reduced thickness (21) in the y direction relative to the laterally adjacent region in the xz plane, to form a reduced resistance between the through-hole contact wires (20) and the aluminum layer (13), wherein the reduced thickness is achieved in particular by grooves (19) in the titanium layer (12), wherein the through-hole contact wires (20) are arranged in the grooves (19) of the titanium layer (12).

7. The MEMS component according to claim 6, wherein, The through-hole contact wire (20) is made of tungsten.

8. The MEMS component according to any of the preceding claims, wherein, The titanium layer (12) has a thickness greater than 100 nanometers, especially greater than 150 nanometers or greater than 180 nanometers.

9. The MEMS component according to any of the preceding claims, wherein, An additional titanium layer (14) is disposed between the aluminum layer (13) and the cover layer (6) of the first printed conductor layer (8), wherein the additional titanium layer (14) has a thickness of less than 20 nanometers, particularly less than 15 nanometers.

10. The MEMS component according to any of the preceding claims, wherein, An additional first printed conductor layer (22) is disposed between the first printed conductor layer (8) and the second printed conductor layer (9), wherein the additional first printed conductor layer (22) has at least one additional first printed conductor (30), wherein the first printed conductor (11) has a layer stack consisting of an aluminum layer and a titanium layer (12) stacked in the y direction, wherein the titanium layer (12) is disposed between the second printed conductor layer (9) and the aluminum layer (13) of the additional first printed conductor layer (22), wherein the titanium layer has a thickness greater than 40 nanometers, wherein the titanium layer is configured as an absorbent layer for binding hydrogen gas released from the copper layer of the second printed conductor layer (9) to reduce or prevent the released hydrogen gas from entering the chamber (4).

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