LASER RESEAL INCLUDING DIFFERENT CAP MATERIALS

Abstract

A method for manufacturing a micromechanical component including a substrate, and a cap connected to the substrate, the cap, together with the substrate, encloses a cavity, a pressure prevailing and a gas mixture having a first chemical composition being enclosed in the cavity. An access opening connecting the cavity to surroundings of the micromechanical component is formed in the substrate or in the cap. The pressure and/or the chemical composition is adjusted in the cavity. The access opening is sealed by introducing energy or heat into an absorbing part of the substrate or the cap with the aid of a laser. A first crystalline, amorphous, nanocrystalline, or polycrystalline layer is deposited or grown on a surface of the substrate or of the cap, and/or a substrate including a second crystalline, amorphous, nanocrystalline, and/or polycrystalline layer, and/or a cap including the second crystalline, amorphous, nanocrystalline, and/or polycrystalline layer is provided.

Claims

1. A method for manufacturing a micromechanical component including a substrate, and a cap connected to the substrate, the cap together with the substrate enclosing a first cavity, a first pressure prevailing and a first gas mixture having a first chemical composition being enclosed in the first cavity, the method comprising: in a first method step, forming, in the substrate or the cap, an access opening connecting the first cavity to surroundings of the micromechanical component; in a second method step, adjusting, in the first cavity, at least one of the first pressure and the first chemical composition; in a third method step, sealing the access opening by introducing energy or heat into an absorbing part of the substrate or the cap, with the aid of a laser; and at least one of: in a fourth method step, deposing or growing on a surface of the substrate or of the cap, one of a first crystalline layer, a first amorphous layer, a first nanocrystalline layer, or a first polycrystalline layer; and in a fifth method step, providing at least one of: i) the substrate including at least one of a second crystalline layer, a second amorphous layer, a second nanocrystalline layer, a second polycrystalline layer, and ii) the cap including at least one of the second crystalline layer, the second amorphous layer, the second nanocrystalline layer, and the second polycrystalline layer.

2. The method as recited in claim 1, further comprising: in a sixth method step, depositing or growing, on the one of the first crystalline layer, first amorphous layer, first nanocrystalline layer, or first polycrystalline layer, one of a third crystalline layer, a third amorphous layer, a third nanocrystalline layer, or a third polycrystalline layer.

3. The method as recited in claim 2, further comprising: in a seventh method step, deposition or growing, on the one of the third crystalline layer, third amorphous layer, third nanocrystalline layer, or third polycrystalline layer, one of a fourth crystalline layer, a fourth amorphous layer, a fourth nanocrystalline layer, or a fourth polycrystalline layer.

4. The method as recited in claim 3, further comprising: in an eighth method step, depositing or growing, on the one of the a fourth crystalline layer, fourth amorphous layer, fourth nanocrystalline layer, or a fourth polycrystalline layer, one of a fifth crystalline layer, a fifth amorphous layer, a fifth nanocrystalline layer, or a fifth polycrystalline layer.

5. The method as recited in claim 4, further comprising: in a ninth method step, doping at least one of: i) the substrate, ii) the cap, iii) the one of the first crystalline layer, first amorphous layer, first nanocrystalline layer, or first polycrystalline layer, iv) the at least one of the second crystalline layer, second amorphous layer, second nanocrystalline layer, and second polycrystalline layer, v) the one of the third crystalline layer, third amorphous layer, third nanocrystalline layer, or third polycrystalline layer, vi) the one of the fourth crystalline layer, fourth amorphous layer, fourth nanocrystalline layer, or fourth polycrystalline layer, and vii) the one of the fifth crystalline layer, fifth amorphous layer, fifth nanocrystalline layer, or fifth polycrystalline layer.

6. The method as recited in claim 4, further comprising: in a tenth method step, at least one of: removing an oxide situated at least partially on or in at least one of: i) the substrate, ii) the cap, iiiiii) the one of the first crystalline layer, first amorphous layer, first nanocrystalline layer, or first polycrystalline layer, iv) the at least one of the second crystalline layer, second amorphous layer, second nanocrystalline layer, and second polycrystalline layer, v) the one of the third crystalline layer, third amorphous layer, third nanocrystalline layer, or third polycrystalline layer, vi) the one of the fourth crystalline layer, fourth amorphous layer, fourth nanocrystalline layer, or fourth polycrystalline layer, and vii) the one of the fifth crystalline layer, fifth amorphous layer, fifth nanocrystalline layer, or fifth polycrystalline layer; and passivating, against oxidation, at least one of: i) the substrate, ii) the cap, iii) the one of the first crystalline layer, first amorphous layer, first nanocrystalline layer, or first polycrystalline layer, iv) the at least one of the second crystalline layer, second amorphous layer, second nanocrystalline layer, and second polycrystalline layer, v) the one of the third crystalline layer, third amorphous layer, third nanocrystalline layer, or third polycrystalline layer, vi) the one of the fourth crystalline layer, fourth amorphous layer, fourth nanocrystalline layer, or fourth polycrystalline layer, and vii) the one of the fifth crystalline layer, fifth amorphous layer, fifth nanocrystalline layer, or fifth polycrystalline layer.

7. A micromechanical component, comprising: a substrate; and a cap connected to the substrate, the cap, together with the substrate, enclosing a first cavity, a first pressure prevailing and a first gas mixture having a first chemical composition being enclosed in the first cavity, one of the substrate or the cap including a sealed access opening; wherein at least one of: i) the micromechanical component includes one of a first crystalline layer, a first amorphous layer, a first nanocrystalline layer, or a first polycrystalline layer, deposited on or grown on a surface of the substrate or of the cap, and ii) one of the the substrate or the cap includes at least one of a second crystalline layer, a second amorphous layer, a second nanocrystalline layer, and a second polycrystalline layer.

8. The micromechanical component as recited in claim 7, wherein the micromechanical component includes one of: i) a third crystalline layer, a third amorphous layer, a third nanocrystalline layer, or a third polycrystalline layer deposited on or grown on the first crystalline layer or on the first amorphous layer or on the first nanocrystalline layer or on the first polycrystalline layer.

9. The micromechanical component as recited in claim 7, wherein the cap, together with the substrate, encloses a second cavity, a second pressure prevailing and a second gas mixture having a second chemical composition being enclosed in the second cavity.

10. The micromechanical component as recited in claim 9, wherein the first pressure is lower than the second pressure, a first sensor unit for rotation rate measurement being situated in the first cavity and a second sensor unit for acceleration measurement being situated in the second cavity.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG. 1 shows a micromechanical component having an open access opening according to one exemplary specific embodiment of the present invention in a schematic representation.

[0052] FIG. 2 shows the micromechanical component according to FIG. 1 having a sealed access opening in a schematic representation.

[0053] FIG. 3 shows a method for manufacturing a micromechanical component according to one exemplary specific embodiment of the present invention in a schematic representation.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0054] Identical parts are denoted by the same reference numerals in the various figures and are therefore generally also cited or mentioned only once.

[0055] FIG. 1 and FIG. 2 show a schematic representation of a micromechanical component 1 having an open access opening 11 in FIG. 1, and having a sealed access opening 11 in FIG. 2, according to one exemplary specific embodiment of the present invention. Micromechanical component 1 includes a substrate 3 and a cap 7. Substrate 3 and cap 7 are, preferably hermetically, connected to one another and together enclose a first cavity 5. For example, micromechanical component 1 is designed in such a way that substrate 3 and cap 7 additionally together enclose a second cavity. The second cavity, however, is not shown in FIG. 1 and in FIG. 2.

[0056] For example, a first pressure prevails in first cavity 5, in particular when access opening 11 is sealed, as shown in FIG. 2. Moreover, a first gas mixture having a first chemical composition is enclosed in first cavity 5. In addition, for example, a second pressure prevails in the second cavity, and a second gas mixture having a second chemical composition is enclosed in the second cavity. Access opening 11 is preferably situated in substrate 3 or in cap 7. In the present exemplary embodiment, access opening 11 is situated in cap 7 by way of example. According to the present invention, however, it may also be alternatively provided that access opening 11 is situated in substrate 3.

[0057] It is provided, for example, that the first pressure in first cavity 5 is lower than the second pressure in the second cavity. It is also provided, for example, that a first micromechanical sensor unit for rotation rate measurement, which is not shown in FIG. 1 and FIG. 2, is situated in first cavity 5, and a second micromechanical sensor unit for acceleration measurement, which is not shown in FIG. 1 and FIG. 2, is situated in the second cavity.

[0058] FIG. 3 shows a method for manufacturing micromechanical component 1 according to one exemplary specific embodiment of the present invention in a schematic representation. In this method,

[0059] in a first method step 101, in particular narrow access opening 11 connecting first cavity 5 to surroundings 9 of micromechanical component 1 is formed in substrate 3 or in cap 7. FIG. 1 shows micromechanical component 1 after first method step 101 by way of example. Moreover,

[0060] in a second method step 102, the first pressure and/or the first chemical composition in first cavity 5 is adjusted, or first cavity 5 is flooded with the desired gas and the desired internal pressure via the access channel. Furthermore, for example,

[0061] in a third method step 103, access opening 11 is sealed by introducing energy or heat with the aid of a laser into an absorbing part 21 of substrate 3 or cap 7. Alternatively, for example, it is also provided that

[0062] in the third method step 103, the area around the access channel is preferably heated only locally by a laser, and the access channel is hermetically sealed. Thus, it is advantageously possible to also provide the method according to the present invention with energy sources other than with a laser for sealing access opening 11. FIG. 2 shows micromechanical component 1 after third method step 103 by way of example.

[0063] Chronologically after third method step 103, it is possible for mechanical stresses to occur in a lateral area 15, shown by way of example in FIG. 2, on a surface facing away from cavity 5 of cap 7 and in the depth perpendicularly to a projection of lateral area 15 onto the surface, i.e., along access opening 11 and in the direction of first cavity 5 of micromechanical component 1. These mechanical stresses, in particular local mechanical stresses, prevail in particular on and in the vicinity of an interface between a material area 13 of cap 7, which in third method step 103 transitions into a liquid aggregate state and after third method step 103 transitions into a solid aggregate state and seals access opening 11, and a remaining area of cap 7, which remains in a solid aggregate state during third method step 103. In FIG. 2, material area 13 of cap 7 sealing access opening 11 is to be regarded only schematically or is shown only schematically, in particular with respect to its lateral extension or form, extending in particular in parallel to the surface, and in particular with respect to its expansion or configuration perpendicularly to the lateral extension, running in particular perpendicularly to the surface.

[0064] As shown in FIG. 3 by way of example,

[0065] in a fourth method step 104, a first crystalline layer or a first amorphous layer or a first nanocrystalline layer or a first polycrystalline layer is deposited on or grown on a surface of substrate 3 or of cap 7 and/or

[0066] in a fifth method step a substrate 3 including a second crystalline layer and/or a second amorphous layer and/or a second nanocrystalline layer and/or a second polycrystalline layer, and/or a cap 7 including the second crystalline layer and/or the second amorphous layer and/or the second nanocrystalline layer and/or the second polycrystalline layer is provided.

[0067] In other words, in fourth method step 104, for example, a layer of a second crystalline, amorphous, nanocrystalline or preferably polycrystalline material or a material packet of the cited materials or layers is applied to a crystalline substrate material or cap material or to the sensor wafer or to the cap wafer. This occurs, for example, at least partially in a fourth method step 104, which chronologically proceeds first method step 101. In other words, it is provided, for example, that fourth method step 104 is carried out chronologically before first method step 101. According to the present invention, it is alternatively or additionally provided, however, that fourth method step 104 is carried out chronologically after third method step 103.

[0068] In addition, in a sixth method step, for example, a third crystalline layer or a third amorphous layer or a third nanocrystalline layer or a third polycrystalline layer is deposited on or grown on the first crystalline layer or on the first amorphous layer or on the first nanocrystalline layer or on the first polycrystalline layer, in particular, for constructing a material packet or layer packet. In addition, in a seventh method step, for example, a fourth crystalline layer or a fourth amorphous layer or a fourth nanocrystalline layer or a fourth polycrystalline layer is deposited on or grown on the third crystalline layer or on the third amorphous layer or on the third nanocrystalline layer or on the third polycrystalline layer. Furthermore, in an eighth method step, for example, a fifth crystalline layer or a fifth amorphous layer or a fifth nanocrystalline layer or a fifth polycrystalline layer is also deposited on or grown on the fourth crystalline layer or on the fourth amorphous layer or on the fourth nanocrystalline layer or on the fourth polycrystalline layer.

[0069] When using a layer packet, it is in particular also provided, for example, that in third method step 103 only the uppermost layer is fused in a target manner.

[0070] Furthermore, it is provided, for example, that instead of a crystalline substrate material or cap wafer or sensor wafer, an amorphous, nanocrystalline or preferably polycrystalline substrate material or cap wafer or sensor wafer is utilized. For this purpose, the fifth method step, for example, is carried out. According to the present invention, it is provided, for example, that the fifth method step is carried out chronologically before the first method step.

[0071] Moreover, it is also provided, for example, that the crystalline, polycrystalline nanocrystalline or amorphous substrate material, the applied layer or the layer packet are doped. For this purpose,

[0072] substrate 3 or cap 7 and/or

[0073] the first crystalline layer or the first amorphous layer or the first nanocrystalline layer or the first polycrystalline layer and/or

[0074] the second crystalline layer and/or the second amorphous layer and/or the second nanocrystalline layer and/or the second polycrystalline layer and/or

[0075] the third crystalline layer or the third amorphous layer or the third nanocrystalline layer or the third polycrystalline layer and/or

[0076] the fourth crystalline layer or the fourth amorphous layer or the fourth nanocrystalline layer or the fourth polycrystalline layer and/or [0077] the fifth crystalline layer or the fifth amorphous layer or the fifth nanocrystalline layer or the fifth polycrystalline layer
are doped, for example, in a ninth method step. It is provided, in particular, for example, that the cap wafer or the sensor wafer or substrate 3 or cap 7 are doped with boron. Furthermore, it is provided, for example, that the ninth method step is carried out chronologically before the first method step. Moreover, it is also provided, for example, that the ninth method step is carried out chronologically after the fifth method step.

[0078] In addition, it is provided, for example, that a natural oxide is removed or that passivation against renewed oxidation occurs. In this case, it is provided, for example, that the natural oxide is removed from the cap wafer or sensor wafer or from cap 7 or from substrate 3. Furthermore, it is also provided, for example, that the cap wafer or the sensor wafer or substrate 3 or cap 7 is protected against renewed oxidation.

[0079] In addition, it is also provided, for example, that the doped or undoped substrate material or the applied material or material packet or the substrate material and the applied material or material packet are fused during the local heating process, for example, during third method step 103.

[0080] Finally, it is provided that the micromechanical component 1 manufactured with the method according to the present invention includes, for example, various cap materials, multilayer caps or modified cap materials, and which differ, for example, from the related art.