Method for manufacturing a composite cap element and composite cap element

Abstract

The present invention relates in particular to a method for manufacturing a composite cap element for encapsulating MEMS components, comprising: (a) providing a base substrate having at least one window formed by an opening on the inside of the base substrate; (b) providing a transparent cover substrate that transparently covers at least one window of the base substrate; (c) the base substrate and the cover substrate having different softening temperatures, the softening temperature of the base substrate being lower than that of the cover substrate; (d) forming an airtight connection between the base substrate and the cover substrate in a connection region formed so as to surround at least the periphery of the window; (e) heating the interconnected substrates in at least the edge region of the window to a temperature at which the base substrate becomes deformable and the cover substrate maintains its shape stability; and (f) a method of displacing the shape-stable cover substrate in the window region while simultaneously deforming the deformable base substrate in the region around the window, as well as to a corresponding composite cap element.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a composite cap element for encapsulating MEMS components, such as MEMS mirrors, and to a corresponding composite cap element.

[0002] When manufacturing a microsystem, the production of the casing plays an important role. This is because the casing determines the construction of the system and the protection of the system from mechanical, chemical and other influences during processing and operation.

[0003] As a method often used, there is so-called wafer-level packaging (WLP) in which predetermined method steps are already carried out before the wafer is cut.

[0004] When manufacturing a casing for a microsystem with movable parts, especially for a microelectromechanical system (MEMS) or a micro-optoelectromechanical system (MOEMS), such as for an acceleration sensor, a gyroscope or a micromirror, a cap element having a defined hollow chamber is often used.

[0005] When a micro-optoelectronic system is encapsulated, a cap element with an optically transparent element is used. In this case, high requirements are often imposed on the surface and geometric properties, and in many cases an airtight encapsulation is desired.

[0006] Furthermore, when a plurality of cap elements are manufactured, it is particularly desirable to achieve a high uniformity of the individual elements over the entire wafer surface.

[0007] Furthermore, in the case of highly efficient MEMS mirrors for scanning applications such as optical projection or LiDAR devices or XR devices, in many cases, the geometry of the casing that reduces parasitic reflections that cause imaging artifacts is targeted.

[0008] The problem underlying the present invention enables high-precision manufacturing, in particular high-precision shaping of transparent elements, high-precision orientation and / or high-precision connection, in order to achieve particularly high uniformity and optical quality. Furthermore, it enables an effective and scalable manufacturing that particularly enables a reduction in the number of method steps, in particular the number of post-processing steps, and provides a method for manufacturing a composite cap element for encapsulating MEMS components, such as MEMS mirrors, as well as a corresponding composite cap element.

[0009] The above problems are solved by the subject matter of each independent claim.

[0010] Advantageous embodiments are defined in each dependent claim.

[0011] The present invention relates in particular to a method for manufacturing a composite cap element for encapsulating MEMS components, such as MEMS mirrors.

[0012] The method includes providing a base substrate having at least one window formed by an opening in the base substrate, and providing a transparent cover substrate that transparently covers at least one window of the base substrate.

[0013] The base substrate and the cover substrate each have different softening temperatures, and the softening temperature of the base substrate is lower than the softening temperature of the cover substrate.

[0014] The method further includes forming a particularly airtight connection between the base substrate and the cover substrate in a connection region formed to surround at least the periphery of the window and hermetically close the window.

[0015] The method further includes heating the interconnected substrates to a temperature at which at least in the edge region of the window, the base substrate becomes deformable and the cover substrate maintains its shape stability.

[0016] The method further includes forming a composite cap element by simultaneously deforming the deformable base substrate in the region around the window while displacing the shape-stable cover substrate in the region of the window.

[0017] As described above, the base substrate and the cover substrate have different softening temperatures. In the framework of the present invention, the softening temperature should be understood in particular as the temperature at which each substrate becomes deformable. Preferably, the softening temperature here is understood to be the temperature at which each substrate reaches a viscosity of 10 7.6 dPas (decipascal seconds).

[0018] As described above, in the framework of the described method, the interconnected substrates are heated to a temperature at which the base substrate becomes deformable while the cover substrate maintains its shape stability. In particular, the interconnected substrates reach a temperature at which the base substrate has a viscosity of less than 10 13 Pas (pascal seconds), preferably a temperature at which the base substrate has a viscosity of less than 10 12 Pas (pascal seconds), particularly preferably a temperature at which the base substrate has a viscosity of less than 10 11 Pas (pascal seconds), more preferably a temperature at which the base substrate has a viscosity of less than 10 9 Pas (pascal seconds), even more preferably a temperature at which the base substrate reaches a predetermined viscosity (10 8 Pas), and the cover substrate maintains a higher viscosity, particularly at least 10 1 Pas or 10 2 Pas higher viscosity.

[0019] In particular, the interconnected substrates are heated to a temperature above the softening temperature of the base substrate and below the softening temperature of the cover substrate.

[0020] Basically, the time sequence of the above-described method steps is not defined. However, preferably, the formation of the airtight connection between the base substrate and the cover substrate is performed before the mutually connected substrates are heated, and / or is configured to be performed while deforming the base substrate in the region around the window and before the cover substrate is displaced in the region of the window.

[0021] The airtight connection formed between the base substrate and the cover substrate can be formed by various methods.

[0022] For example, the airtight connection between the base substrate and the cover substrate can be formed using laser welding, and / or can be formed such that the connection region surrounding the periphery of the window is formed linearly.

[0023] Note that the airtight connection may be performed using anodic bonding and / or such that the connection region surrounding the periphery of the window is formed in a planar shape.

[0024] As described above, in the method, the window provided on the base substrate is closed by a transparent cover substrate. At this time, the cover substrate is placed on the base substrate by overlapping with the base substrate on the edge side, particularly in the region of the window.

[0025] Therefore, in this case, the particularly annular surface of the cover substrate contacts the particularly annular surface of the base substrate.

[0026] Preferably, at least the surfaces of the two substrates that contact each other, or the entire substrates, are formed flat or in a planar shape.

[0027] In particular, it can be configured such that the base substrate is formed at least partially in a planar shape, particularly in a planar shape, and / or the transparent cover substrate is formed at least partially in a planar shape, particularly in a planar shape.

[0028] In this way, by covering the window in the base substrate with the cover substrate, the transparent cover substrate preferably makes planar contact with the base substrate within the contact region around at least one window.

[0029] The contact region can have a width of at least 10 μm, preferably at least 50 μm, particularly preferably at least 800 μm, especially surrounding the periphery of the window.

[0030] In a preferred embodiment, it is configured such that there is a connection quality index Q of 0.8 or more, preferably 0.9 or more, more preferably 0.95 or more, between the base substrate and the cover substrate.

[0031] In this case, the connection quality index Q is Q = 1 - (A - G) / A, where A represents the area of the contact region between the base substrate and the cover substrate, and G represents the area of the article where the distance between the substrates inside is less than 5 μm, preferably less than 2 μm, more preferably less than 1 μm, even more preferably less than 0.3 μm.

[0032] Depending on whether the cover substrate already has the desired dimensions when placed on the base substrate or the desired dimensions are only formed after placement, method steps for adapting the dimensions of the cover substrate can be optionally provided.

[0033] In particular, the method includes introducing a separation path around at least one window of the base substrate across the cover substrate in many method variants.

[0034] Here, the separation path can be introduced into the cover substrate, particularly after an airtight connection is formed between the base substrate and the cover substrate.

[0035] The separation path can preferably extend so as to surround the connection area, in particular (for example in the case of laser welding) can extend so as to surround the linear connection area, or (for example in the case of anode bonding) can extend into the connection area, in particular can extend into the planar connection area.

[0036] The separation path can be introduced into the cover substrate, for example, using laser ablation.

[0037] Particularly with regard to MEMS mirrors, but basically independently of MEMS mirrors, in the final composite cap element, it may be desirable for the cover substrate to be inclined with respect to the base substrate.

[0038] From such a background, in the method, in particular, while simultaneously deforming the base substrate in the area around the window, displacing the cover substrate in the area of the window can be configured to be performed such that the cover substrate is inclined with respect to the base substrate in the area of the window.

[0039] Such an inclined portion of the cover substrate in the area of the window can particularly have an angle of 1° to 45°, preferably an angle of 10° to 25°.

[0040] As a tool for performing the displacement or deformation, for example, a stamp that can act on the cover substrate or the base substrate can be used.

[0041] Therefore, the displacement of the cover substrate in the area of the window can be performed using a stamp that acts on the cover substrate with pressure such that the base substrate is deformed in the area around the window.

[0042] In this case, as an optional means, for example, in order to increase the connection quality index and / or strengthen the connection part, an opposing surface facing the stamp can be provided, and the base substrate is pressed against the opposing surface.

[0043] The displacement of the cover substrate in the window area can alternatively or additionally be effected by means of a stamp which exerts pressure on the base substrate in the area around the window, such that the base substrate is deformed in the area around the window.

[0044] As an optional measure, a counter surface can furthermore be provided opposite the stamp, against which the cover substrate is pressed. Here, the counter surface can be formed, for example, by another stamp.

[0045] The stamp and / or the counter surface can each be formed as a collar surrounding the periphery, which collar acts on each substrate, in particular in the area of the connection region and / or the contact region. Thereby, for example, it is possible to keep optically important areas of the cover substrate independent of pressure.

[0046] Furthermore, the stamp and / or the counter surface can be configured to be heated, for example in order to increase the connection quality index and / or to strengthen the connection.

[0047] In one development of the invention, the cover substrate can be coated, for example using an anti-reflection coating and / or using a specific filter layer, for example a filter layer for RGB transmittance or NIR transmittance. Also in the case of carrying out such a coating, it is advantageous for the stamp to be a collar surrounding the periphery so as not to damage the abovementioned layers.

[0048] As described above, the base substrate and the cover substrate each have different softening temperatures.

[0049] The mutually different softening temperatures of the base substrate and the cover substrate can, for example, differ from one another by at least 50 K, preferably by at least 100 K, and particularly preferably by at least 150 K.

[0050] Alternatively or additionally, different softening temperatures of the base substrate and the cover substrate may be such that the viscosities of the two substrates differ by at least 10 0.5 Pas from each other, preferably at least 10 1 Pas from each other, particularly preferably at least 10 2 Pas from each other and can be made to differ from each other.

[0051] Regarding the material, the base substrate may particularly comprise or consist of one of the following materials, namely glass, in particular borosilicate glass, soda-lime glass, alkali borosilicate glass, alkali borate glass, alkali phosphate glass, zinc borate glass, lead-containing glass, vanadate glass, zinc stannate phosphate glass. Note that the base substrate may also comprise or consist of at least one of the materials listed below for the cover substrate.

[0052] The cover substrate may particularly comprise or consist of one of the following materials, namely glass, in particular aluminosilicate glass, aluminoborosilicate glass, rare earth aluminosilicate glass, alkaline earth aluminosilicate glass, glass ceramic, fused silica, sapphire, silicon, germanium. Note that the cover substrate may also comprise or consist of at least one of the materials listed above for the base substrate.

[0053] Some preferred embodiments are given below.

[0054] In some embodiments, the strength of the connection between the base substrate and the cover substrate, in particular the shear strength at room temperature, is preferably at least 10 MPa.

[0055] In some embodiments, the coefficient of thermal expansion of the base substrate is 2×10 -6 K -1 ~10×10 -6 K -1 Thereby.

[0056] In some embodiments, the coefficient of thermal expansion of the cover substrate is 2×10 -6 K -1 ~10×10 -6 K -1 .

[0057] In some embodiments, the absolute value of the difference in the coefficient of thermal expansion between the base substrate and the cover substrate is less than 5×10 -6 K -1 , preferably less than 2×10 -6 K -1 , particularly preferably less than 1×10 -6 K -1 .

[0058] In some embodiments, the base substrate has a thickness of 0.02 mm to 5 mm.

[0059] In some embodiments, the cover substrate has a thickness of 0.02 mm to 5 mm.

[0060] In some embodiments, at least one window of the base substrate has an area of 0.5 mm×0.5 mm to 50 mm×50 mm.

[0061] In some embodiments, the cover substrate has a surface with an average roughness R of 15 nm or less, preferably 10 nm or less, particularly preferably 5 nm or less a .

[0062] In some embodiments, the cover substrate, particularly the optically important portion of the window, has a flatness of less than 20 μm.

[0063] In some embodiments, the cover substrate has a thickness variation of less than 5% of the average thickness across the area of the window.

[0064] In some embodiments, the cover substrate has a transmittance of at least 90% for wavelengths from 300 nm to 2500 nm.

[0065] As described above, the method includes providing a base substrate having at least one window. However, in one development form, a plurality of windows can also be provided on the base substrate.

[0066] Accordingly, the base substrate in one development form can have a plurality of windows, and the plurality of windows are each formed by an opening in the base substrate, where the plurality of windows are preferably arranged in a regular pattern.

[0067] In this case, a transparent cover substrate can be provided to cover the plurality of windows simultaneously, and / or a plurality of transparent cover substrates provided to cover one or more windows respectively can be prepared.

[0068] Preferably, a hermetic connection portion between the base substrate and the cover substrate is formed so as to surround the periphery of each window, in particular by forming a linear connection region around each window using laser welding, and / or by forming a planar, for example, a connection region over the entire surface, between the substrates using anodic bonding.

[0069] Furthermore, the interconnected substrates are preferably heated at least in the region of each window, for example continuously in the region of each window, or particularly preferably simultaneously as a whole.

[0070] Furthermore, the cover substrate is preferably displaced while simultaneously deforming the base substrate, for example continuously or particularly preferably simultaneously as a whole in the region of each window, where, for such displacement, for example, a plurality of stamps defining a uniform inclination for a plurality of displacements or deformations can be used.

[0071] The present invention further relates to a method for manufacturing encapsulated MEMS components, comprising providing a support substrate with an MEMS component, for example an MEMS mirror, and further attaching and particularly hermetically connecting a composite cap element, in particular a composite cap element manufactured as described above, onto the support substrate such that the MEMS component is hermetically sealed between the support substrate and the composite cap element.

[0072] The present invention further relates to a composite cap element for encapsulating an MEMS component, for example an MEMS mirror, manufactured or manufacturable according to the method described above.

[0073] The present invention further relates to a composite cap element for encapsulating an MEMS component, for example an MEMS mirror.

[0074] The composite cap element includes a base substrate having at least one window formed by an opening in the base substrate, and a transparent cover substrate that transparently covers at least one window of the base substrate.

[0075] The composite cap element further has a particularly airtight connection between the base substrate and the cover substrate in a connection region formed so as to surround at least the periphery of the window such that the window is particularly hermetically closed.

[0076] The base substrate has a deformation portion in a region around the window such that the cover substrate is displaced and positioned with respect to the base substrate.

[0077] Furthermore, the base substrate and the cover substrate each have a different softening temperature, where the softening temperature of the base substrate is lower than the softening temperature of the cover substrate.

[0078] The airtight connection between the base substrate and the cover substrate can be formed linearly, in particular as a laser welding seam.

[0079] The hermetic connection between the base substrate and the cover substrate can be formed in a planar manner, particularly as an anode bonding portion.

[0080] The base substrate is formed at least partially in a planar manner, particularly in a flat shape. Further, the transparent cover substrate is formed at least partially in a planar manner, particularly in a flat shape.

[0081] The transparent cover substrate preferably contacts the base substrate in a planar manner within the contact region around at least one window, whereby at least one window of the base substrate is transparently covered.

[0082] The contact region can particularly have a width of at least 10 μm, preferably at least 50 μm, particularly preferably at least 800 μm, surrounding the periphery of the window.

[0083] There is particularly a connection quality index Q of 0.8 or more, preferably 0.9 or more, more preferably 0.95 or more, between the base substrate and the cover substrate.

[0084] In this case, the connection quality index Q is Q = 1 - (A - G) / A, where A represents the area of the contact region between the base substrate and the cover substrate, and G represents the area of the article where the distance between the substrates inside is less than 5 μm, preferably less than 2 μm, more preferably less than 1 μm, and even more preferably less than 0.3 μm.

[0085] The composite cap element can further have a separation path extending across the cover substrate and surrounding at least one window.

[0086] The separation path preferably extends so as to surround the periphery of the connection region, particularly so as to surround the periphery of a linear connection region, or extends inside the connection region, particularly inside a planar connection region.

[0087] The deformed part of the base substrate is preferably formed such that the cover substrate is inclined with respect to the base substrate in the window region, where the inclined part of the cover substrate has an angle of particularly 1° to 45°, preferably 10° to 25° in the window region.

[0088] The mutually different softening temperatures of the base substrate and the cover substrate may differ from each other by at least 50 K, preferably by at least 100 K, and particularly preferably by at least 150 K.

[0089] The base substrate may particularly contain or consist of one of the following materials, namely, glass, particularly borosilicate glass, soda-lime glass, alkali borosilicate glass, alkali borate glass, alkali phosphate glass, zinc borate glass, lead-containing glass, vanadate glass, zinc stannate phosphate glass.

[0090] The cover substrate may particularly contain or consist of one of the following materials, namely, glass, particularly aluminosilicate glass, aluminoborosilicate glass, rare earth aluminosilicate glass, alkaline earth aluminosilicate glass, glass ceramic, fused silica, sapphire, silicon, germanium.

[0091] The strength of the connection part between the base substrate and the cover substrate, particularly the shear strength at room temperature, may be at least 10 MPa.

[0092] The coefficient of thermal expansion of the base substrate is 2×10 -6 K -1 ~10×10 -6 K -1 and may be.

[0093] The coefficient of thermal expansion of the cover substrate is 2×10 -6 K -1 ~10×10 -6 K -1 and may be.

[0094] The absolute value of the difference in the coefficient of thermal expansion between the base substrate and the cover substrate is 5×10 -6 K -1 or less, preferably 2×10 -6 K -1 or less, particularly preferably 1×10 -6 K -1 or less.

[0095] The base substrate can have a thickness of 0.02 mm to 5 mm.

[0096] The cover substrate can have a thickness of 0.02 mm to 5 mm.

[0097] At least one window of the base substrate can have an area of 0.5 mm × 0.5 mm to 50 mm × 50 mm.

[0098] The cover substrate can have a surface with an average roughness R of 15 nm or less, preferably 10 nm or less, particularly preferably 5 nm or less. a

[0099] The cover substrate, particularly the optically important part of the window, can have a flatness of less than 20 μm.

[0100] The cover substrate can have a thickness variation of less than 5% of the average thickness over the area of the window.

[0101] The cover substrate can have a transmittance of at least 90% for wavelengths of 300 nm to 2500 nm.

[0102] The base substrate can have a plurality of windows formed by openings in the base substrate, and the plurality of windows are preferably arranged in a regular pattern.

[0103] A transparent cover substrate can cover a plurality of windows simultaneously, and / or a plurality of transparent cover substrates covering one or a plurality of windows respectively can be provided.

[0104] Preferably, an airtight connection portion between the base substrate and the cover substrate is provided so as to surround the periphery of each window.

[0105] The base substrate preferably has a deformable portion such that the cover substrate is displaced and positioned with respect to the base substrate in a region around each window.

[0106] The present invention further relates to an encapsulated MEMS component, comprising a support substrate having an MEMS component, for example an MEMS mirror, and a composite cap element according to the above description in particular, the composite cap element being deposited on the support substrate and being particularly airtightly connected such that the MEMS component is also particularly airtightly sealed between the support substrate and the composite cap element.

[0107] Hereinafter, the present invention will be described in detail with reference to the drawings.

Brief Description of the Drawings

[0108]

Figure 1

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Figure 21

[0109] In FIGS. 1 and 2, a base substrate 100 having a window 110 and a cover substrate 200 on which the base substrate is placed are shown respectively. In FIG. 1, the cover substrate 200 is already adapted to the geometry of the window 110. However, since the cover substrate 200 is somewhat larger than the window 110 existing on the base substrate 110, the window 110 is completely covered, and an overlap portion of the two substrates occurs so as to surround the periphery of the window 110, and at this overlap portion, each substrate can be connected in the next step. In FIG. 2, the cover substrate 200 has a geometry similar to that of the base substrate 100, and thus covers the entire surface of the base substrate 100.

[0110] FIGS. 3 to 5 show an exemplary first sequence of method steps for manufacturing a composite cap element.

[0111] In the method step shown in FIG. 3, a connection portion 310 is formed between the base substrate 100 and a cover substrate 200 in contact with the base substrate 100, for example according to FIG. 1, in this case by laser welding for example. The connection portion 310 is formed so as to surround the periphery of the window 110, whereby the window 110 is hermetically closed by the cover substrate 200.

[0112] In the method step shown in FIG. 4, the interconnected substrates are heated or are to be heated such that the base substrate 100 is deformable while the cover substrate 200 maintains its shape stability. Thermoforming is performed by means of a stamp 500 having a stamp surface inclined with respect to the base substrate 100. In this case, pressure is applied to the deformable base substrate 100 in the region surrounding the window 110 including the connection portion 310, whereby the edge region surrounding the window 110 of the base substrate 100 is deformed, and the cover substrate 200 fixed at this location is displaced and inclined with respect to the base substrate 100 at the same time.

[0113] FIG. 5 shows the composite cap element thus obtained together with a contact region 400 surrounding the window 110, the contact region 400 having a linear connection portion 310 at which the two substrates are in contact with each other and preferably having a connection quality index Q of 0.8 or more.

[0114] FIGS. 6 to 9 show an exemplary second sequence of method steps for manufacturing a composite cap element, where the sequence is in some aspects the same as the first sequence and in other aspects different from the first sequence.

[0115] In the method step shown in FIG. 6, an airtight connection portion 310 between the substrates, surrounding the window 110, is formed between the base substrate 100 and a cover substrate 200 placed over the entire surface, for example according to FIG. 2, also using laser welding in this example.

[0116] In the method step shown in FIG. 7, a separation path 250 is introduced, for example using laser ablation, across the cover substrate 200 so as to surround the window 110. In this case, the separation path 250 extends so as to surround the linear connection portion 310. Thereby, the geometry of the cover substrate 200 is adapted to the geometry of the window 110, and the excess outer portion of the cover substrate 200 can be discarded.

[0117] In the method step shown in FIG. 8, in order to perform thermoforming using the stamp 500, the interconnected substrates are heated again. In this example, in order to displace and tilt the cover substrate 200, pressure is applied to the shape-stable cover substrate 200 by the stamp 500, and at this time, the edge region surrounding the window 110 in the deformable base substrate 100 is pulled out, whereby the composite cap element shown in FIG. 9 is formed.

[0118] FIGS. 10 to 13 show an exemplary third sequence of method steps for manufacturing a composite cap element, where the sequence is in some aspects similar to the first sequence or the second sequence and in other aspects different from the first sequence or the second sequence.

[0119] In the method step shown in FIG. 10, a first airtight connection portion 310 between the two substrates surrounding the window 110 is formed between the base substrate 100 and the cover substrate 200 placed over the entire surface, for example according to FIG. 2. Further, in this example, a second airtight connection portion 310 between the substrates surrounding the periphery is formed, where the two connection portions 310 are formed as linear connection portions using laser welding. The second connection portion extends so as to surround the first connection portion.

[0120] In the method step shown in FIG. 11, a separation path 250 is introduced across the cover substrate 200 so as to surround the window 110, where the separation path is introduced between the first connection portion 310 surrounding the periphery and the second connection portion 310 surrounding the periphery. Thereby, on the one hand, the geometry of the cover substrate 200 for the window 110 to be pulled out is defined, and at the same time, the outer portion of the cover substrate 200 is connected to the base substrate.

[0121] In the method step shown in FIG. 12, the substrate is reheated or heated, and the inner portion of the shape-stable cover substrate 200, which is separated from the outer portion by the separation line 250, is displaced using the stamp 500, thereby forming the composite cap element shown in FIG. 13.

[0122] FIGS. 14 to 17 show an exemplary fourth sequence of method steps for manufacturing a composite cap element, where the sequence is, in some aspects, similar to the first sequence or the second sequence or the third sequence, and in other aspects, different from the first sequence or the second sequence or the third sequence.

[0123] In the method step shown in FIG. 14, a planar connection portion 310 is formed between the base substrate 100 and the cover substrate 200 placed over the entire surface, for example according to FIG. 2, using anode bonding in this example. The connection portion 310 is formed over the entire surface in this example, and thus is also formed particularly in the contact region 400 surrounding the window 110 among the two substrates.

[0124] In the method step shown in FIG. 15, a separation path 250 is introduced across the cover substrate 200 so as to surround the window 110. In this case, the separation path extends through the planar connection portion 310. The separation path 250 extends through the region of the planar connection portion 310 particularly also in the transverse direction with respect to the substrate plane. Thereby, on the one hand, for the cover substrate 200, an inner portion covering the window 110 is defined, and further, an outer portion separated from the inner portion by the separation line 250 is defined, similar to the inner portion connected to the base substrate by the connection portion 310.

[0125] In the method step shown in FIG. 16, the substrate is reheated or heated, and the inner portion of the shape-stable cover substrate 200 is displaced using the stamp 500, thereby forming the composite cap element shown in FIG. 17.

[0126] Figures 18 and 19 show development forms particularly regarding displacement steps and deformation steps. In this case, the stamp 500 is formed, for example, as a color surrounding the periphery, and the color is configured to apply a desired pressure to the contact region 400 between the substrates surrounding the periphery.

[0127] Thereby, for example, the connection quality index can be improved. Further, as shown in FIG. 19, particularly when pressure is applied to the cover substrate 200, the inner portion of the cover substrate 200, particularly the optically important portion, can be displaced without contacting the stamp 500.

[0128] Similarly, an opposing surface 550 can be provided at a position facing the stamp 500, and the contact region 400 between the two substrates is pressed against the opposing surface. The opposing surface 550 is also formed as a color surrounding the periphery in this example. However, it should be understood that this is merely an illustration. It is of course also possible to form the stamp 500 and / or the opposing surface 550 differently from each other.

[0129] In FIGS. 20 and 21, as in FIGS. 1 and 2, one base substrate 100 is shown respectively, but the base substrate 100 includes a plurality of windows 110 and one or more cover substrates 200 covering these windows. Starting from such a substrate, the above-described method sequences can be particularly performed simultaneously using a plurality of windows respectively.

Claims

1. 1. A method for manufacturing a composite cap element, in particular for encapsulation of a MEMS component, for example a MEMS mirror, comprising: providing a base substrate (100) having at least one window (110) formed by an opening inside the base substrate; providing a transparent cover substrate (200) that transparently covers the at least one window (110) of the base substrate (100), wherein the base substrate and the cover substrate have different softening temperatures, the softening temperature of the base substrate being lower than the softening temperature of the cover substrate; forming a particularly gas-tight connection (310) between the base substrate (100) and the cover substrate (200) at least in a connection area (300) formed around the periphery of the window (110) and so as to close the window gas-tightly; heating the interconnected substrates, at least in the edge region of the window, to a temperature at which the base substrate becomes deformable and the cover substrate remains shape-stable, in particular to a temperature above the softening temperature of the base substrate and below the softening temperature of the cover substrate; displacing the form-stable cover substrate in the region of the window while simultaneously deforming the deformable base substrate in the region around the window to form a composite cap element; A method comprising:

2. the formation of the hermetic connection (310) between the base substrate (100) and the cover substrate (200) is performed before the interconnected substrates are heated and / or before the cover substrate (200) is displaced in the region of the window (110) while simultaneously deforming the base substrate (100) in the region around the window; The method of claim 1.

3. the hermetic connection (310) between the base substrate and the cover substrate is formed by means of laser welding, in particular so that the connection area surrounding the periphery of the window is formed linearly; and / or The airtight connection (310) between the base substrate and the cover substrate is formed by anodic bonding, in particular so that the connection area surrounding the periphery of the window is formed in a planar shape.

3. The method according to claim 1 or 2.

4. the base substrate is at least partially areal, in particular planar, and / or the transparent cover substrate is at least partially areal, in particular planar, and / or the transparent cover substrate in a contact region (400) is in surface contact with the base substrate around the at least one window, thereby transparently covering the at least one window of the base substrate; the contact area (400) has a width, in particular surrounding the window, of at least 10 μm, preferably at least 50 μm, particularly preferably at least 800 μm, the connection between the base substrate and the cover substrate has a connection quality index Q of, in particular, 0.8 or more, preferably 0.9 or more, and more preferably 0.95 or more, The connection quality index Q is defined as Q=1-(A-G) / A, where A is the area of ​​the contact region between the base substrate and the cover substrate, and G is the area of ​​the article within which the distance between the substrates is less than 5 μm, preferably less than 2 μm, more preferably less than 1 μm, and even more preferably less than 0.3 μm.

3. The method according to claim 1 or 2.

5. The method further includes introducing a separation path (250) across the cover substrate (200) and surrounding the periphery of the at least one window; the separation path (250) is introduced in particular into the cover substrate after the hermetic connection between the base substrate and the cover substrate has been formed, The separation path (250) preferably extends around the periphery of the connection area, in particular around the periphery of a linear connection area, or extends within the connection area, in particular within a planar connection area; The separation paths (250) are preferably introduced into the cover substrate using laser ablation.

3. The method according to claim 1 or 2.

6. displacing the cover substrate in the window region while simultaneously deforming the base substrate in the region around the window such that the cover substrate is tilted relative to the base substrate in the window region; the inclined portion of the cover substrate in the region of the window has an angle of, in particular, 1° to 45°, preferably 10° to 25°; 3. The method according to claim 1 or 2.

7. The displacement of the cover substrate in the region of the window is achieved by a stamp (500) that exerts pressure on the cover substrate so that the base substrate is deformed in the region around the window, optionally with a counter surface (550) facing the stamp (500) against which the base substrate (100) is pressed; and / or the displacement of the cover substrate in the region of the window is effected by a stamp (500) exerting pressure on the base substrate in the region around the window so that the base substrate is deformed in the region around the window, optionally with a counter surface (550) opposite the stamp (500) against which the cover substrate (200) is pressed; and / or the stamp (500) and / or the counter surface (550) are formed as a surrounding collar, which acts on the respective substrate in the region of the connection area (300) and / or the contact area (400); and / or The stamp (500) and / or the facing surface (550) are heated; 3. The method according to claim 1 or 2.

8. the softening temperatures of the base substrate and the cover substrate differ from one another by at least 50 K, preferably by at least 100 K, particularly preferably by at least 150 K, and / or The different softening temperatures of the base substrate and the cover substrate are such that the viscosities of the two substrates are at least 10 at the softening temperature of the base substrate and / or the softening temperature of the cover substrate. ０．５ Pas are different from each other, preferably at least 10 １ Pas are different from each other, particularly preferably at least 10 ２ Pas differ from each other, differ from each other, the base substrate in particular comprises or consists of one of the following materials: glass, in particular borosilicate glass, soda-lime glass, alkali borosilicate glass, alkali borate glass, alkali phosphate glass, zinc borate glass, lead-containing glass, vanadate glass, zinc tin phosphate glass; The cover substrate in particular comprises or consists of one of the following materials: glass, in particular aluminosilicate glass, aluminoborosilicate glass, rare earth aluminosilicate glass, alkaline earth aluminosilicate glass, glass ceramic, quartz glass, sapphire, silicon, germanium; 3. The method according to claim 1 or 2.

9. the strength of the connection between the base substrate and the cover substrate, in particular the shear strength at room temperature, is at least 10 MPa; The thermal expansion coefficient of the base substrate is 2×10 －６ K －１ ~10 x 10 －６ K －１ and / or The thermal expansion coefficient of the cover substrate is 2×10 －６ K －１ ~10 x 10 －６ K －１ and / or The absolute value of the difference in thermal expansion coefficient between the base substrate and the cover substrate is 5×10 －６ K －１ is less than 2×10 －６ K －１ less than 1×10 －６ K －１ is less than and / or the base substrate has a thickness of 0.02 mm to 5 mm; and / or the cover substrate has a thickness of 0.02 mm to 5 mm; and / or the at least one window in the base substrate has an area of ​​0.5 mm x 0.5 mm to 50 mm x 50 mm; 3. The method according to claim 1 or 2.

10. The cover substrate has an average roughness R of 15 nm or less, preferably 10 nm or less, and particularly preferably 5 nm or less. ａ and / or the cover substrate, in particular the optically important part of the window, has a flatness of less than 20 μm; and / or the cover substrate has a thickness variation of less than 5% of the average thickness, in particular over the area of ​​the window; and / or The cover substrate has a transmittance of at least 90% for wavelengths of 300 nm to 2500 nm.

3. The method according to claim 1 or 2.

11. the base substrate has a plurality of windows, each formed by an opening in the base substrate, the plurality of windows preferably arranged in a regular pattern; a transparent cover substrate is provided to simultaneously cover the plurality of windows, or a plurality of transparent cover substrates are provided, each of which is provided to cover one or more windows; an airtight connection is formed between the base substrate and the cover substrate, preferably around each window, in particular by forming linear connection areas around each window, in particular by laser welding, and / or by forming area connection areas, for example full-surface connection areas, between the substrates, in particular by anodic bonding, the interconnected substrates are heated, preferably at least in the region of each window, for example sequentially in the region of each window or simultaneously as a whole; The cover substrate is preferably displaced in the region of each window while simultaneously deforming the base substrate, e.g. successively in the region of each window or simultaneously as a whole.

3. The method according to claim 1 or 2.

12. 1. A method for manufacturing an encapsulated MEMS component, comprising: Providing a carrier substrate with a MEMS component, e.g. a MEMS mirror; - applying and hermetically connecting a composite cap element producible or produced according to claim 1 or 2 onto the carrier substrate, such that the MEMS component is hermetically sealed between the carrier substrate and the composite cap element. A method comprising:

13. 3. A composite cap element for encapsulating a MEMS component, for example a MEMS mirror, produced or producible according to claim 1 or 2.

14. 1. A composite cap element for encapsulation of a MEMS component, for example a MEMS mirror, comprising: a base substrate (100) having at least one window (110) formed by an opening in the base substrate (100); a transparent cover substrate (200) that transparently covers the at least one window (110) of the base substrate (100); an airtight connection (310) between the base substrate (100) and the cover substrate (200) in a connection region (300), the connection region (300) being formed around at least the periphery of the window so that the window is airtightly closed; and Equipped with the base substrate has a deformation (150) in a region around the window such that the cover substrate is displaced and positioned relative to the base substrate; the base substrate and the cover substrate have different softening temperatures, and the softening temperature of the base substrate is lower than the softening temperature of the cover substrate; Composite cap element.

15. the gas-tight connection (310) between the base substrate and the cover substrate is formed linearly, in particular as a laser-welded seam, and / or The hermetic connection (310) between the base substrate and the cover substrate is formed in a planar manner, in particular as an anodic bonding portion. The composite cap element of claim 14.

16. the base substrate is at least partially areal, in particular planar, and / or the transparent cover substrate is at least partially areal, in particular planar, and / or the transparent cover substrate is in surface contact with the base substrate in a contact region (400) around the at least one window, thereby transparently covering the at least one window of the base substrate; the contact area (400) has a width of at least 10 μm, preferably at least 50 μm, particularly preferably at least 800 μm, in particular surrounding the window; the connection between the base substrate and the cover substrate has a connection quality index Q of, in particular, 0.8 or more, preferably 0.9 or more, and more preferably 0.95 or more, The connection quality index Q is defined as Q=1-(A-G) / A, where A represents the area of ​​the contact region between the base substrate and the cover substrate, and G represents the area of ​​the article within which the distance between the substrates is less than 5 μm, preferably less than 2 μm, more preferably less than 1 μm, and even more preferably less than 0.3 μm.

16. The composite cap element of claim 14 or 15.

17. the composite cap element further includes a separation path (250) that traverses the cover substrate (200) and surrounds the periphery of the at least one window; The separation path (250) preferably extends around the periphery of the connection area, in particular around the periphery of a linear connection area, or extends within the connection area, in particular within a planar connection area.

16. The composite cap element of claim 14 or 15.

18. the deformation (150) of the base substrate is formed such that the cover substrate is inclined relative to the base substrate in the region of the window, the inclined portion of the cover substrate in the region of the window has an angle of, in particular, 1° to 45°, preferably 10° to 25°; 16. The composite cap element of claim 14 or 15.

19. the softening temperatures of the base substrate and the cover substrate differ from one another by at least 50 K, preferably by at least 100 K, particularly preferably by at least 150 K, the base substrate in particular comprises or consists of one of the following materials: glass, in particular borosilicate glass, soda-lime glass, alkali borosilicate glass, alkali borate glass, alkali phosphate glass, zinc borate glass, lead-containing glass, vanadate glass, zinc tin phosphate glass; The cover substrate in particular comprises or consists of one of the following materials: glass, in particular aluminosilicate glass, aluminoborosilicate glass, rare earth aluminosilicate glass, alkaline earth aluminosilicate glass, glass ceramic, quartz glass, sapphire, silicon, germanium; 16. The composite cap element of claim 14 or 15.

20. the strength of the connection between the base substrate and the cover substrate, in particular the shear strength at room temperature, is at least 10 MPa; The thermal expansion coefficient of the base substrate is 2×10 －６ K －１ ~10 x 10 －６ K －１ and / or The thermal expansion coefficient of the cover substrate is 2×10 －６ K －１ ~10 x 10 －６ K －１ and / or The absolute value of the difference in thermal expansion coefficient between the base substrate and the cover substrate is 5×10 －６ K －１ is less than 2×10 －６ K －１ less than 1×10 －６ K －１ is less than and / or the base substrate has a thickness of 0.02 mm to 5 mm; and / or the cover substrate has a thickness of 0.02 mm to 5 mm; and / or the at least one window in the base substrate has an area of ​​0.5 mm x 0.5 mm to 50 mm x 50 mm; 16. The composite cap element of claim 14 or 15.

21. The cover substrate has an average roughness R of 15 nm or less, preferably 10 nm or less, particularly preferably 5 nm or less. ａ and / or the cover substrate, in particular the optically important part of the window, has a flatness of less than 20 μm; and / or the cover substrate has a thickness variation of less than 5% of the average thickness, in particular over the area of ​​the window; and / or The cover substrate has a transmittance of at least 90% for wavelengths of 300 nm to 2500 nm.

16. The composite cap element of claim 14 or 15.

22. the base substrate has a plurality of windows, each formed by an opening in the base substrate, the plurality of windows preferably being arranged in a regular pattern; the transparent cover substrate covers multiple windows simultaneously, or multiple transparent cover substrates are provided, each covering one or more windows; Preferably, the airtight connection between the base substrate and the cover substrate is provided so as to surround the periphery of each window, The base substrate preferably has deformations (150) in the area around each window so that the cover substrate is displaced and positioned relative to the base substrate.

16. The composite cap element of claim 14 or 15.

23. 1. An encapsulated MEMS component, comprising: a carrier substrate with a MEMS component, e.g. a MEMS mirror; The composite cap element according to claim 14 or 15; Equipped with the composite cap element is deposited on the carrier substrate and is hermetically connected such that the MEMS component is hermetically sealed between the carrier substrate and the composite cap element. Encapsulated MEMS components.

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