Package and method for producing a package

Abstract

This invention relates to a package comprising a substrate (11) and a MEMS wafer (1), wherein the MEMS wafer (1) is fixed on the substrate (11). Another aspect of this invention relates to a method for manufacturing the package.

Description

Technical Field

[0001] This invention relates to a package and a method for manufacturing the package. Prior Technology

[0002] Here, packaging refers to a shell and protective structure that contains and surrounds the MEMS chip. This packaging plays a crucial role in the functionality, reliability, and durability of the MEMS chip.

[0003] In the package, MEMS chips should be protected from damage and environmental impacts during device installation. Summary of the Invention

[0004] The objective of this invention is to specify an advantageous package suitable for, for example, optical MEMS systems.

[0005] This objective is achieved through the content of a separate request item. An advantageous implementation is through the content of an auxiliary request item.

[0006] A package is proposed that includes a substrate and a MEMS chip fixed on the substrate.

[0007] A MEMS chip may contain at least one electronic component. This electronic component may be disposed on one side of the MEMS chip. The MEMS chip may be fixed to a substrate such that the side of the MEMS chip containing the electronic component faces the substrate.

[0008] MEMS chips can include multiple electronic components, all of which are arranged on the side of the MEMS chip facing the substrate.

[0009] A MEMS wafer may include at least one arrangement of electronic components disposed on the side of the MEMS wafer away from the substrate. A MEMS wafer may include multiple arrangements of electronic components disposed on the side of the MEMS wafer away from the substrate.

[0010] MEMS chips can contain at least two electronic components, one of which is located on the side of the MEMS chip away from the substrate, and the other is located on the side of the MEMS chip facing the substrate.

[0011] The electronic component can be a driving element, a movable element designed to move a MEMS wafer. These driving elements can include piezoelectric actuators.

[0012] The arrangement of electronic components on the substrate-facing side of a MEMS chip can be achieved by fixing the MEMS chip onto the substrate using a flip-chip method. By fixing the MEMS chip onto the substrate using this method, the electrical contacts of the substrate are located directly beneath the MEMS chip, thus eliminating the need for the substrate area adjacent to the MEMS chip to make contact with it. This allows for a smaller overall package design.

[0013] Furthermore, the flip-chip mounting method may allow the use of MEMS wafers made from a single silicon layer. The second silicon layer, which serves as a spacer between the movable elements of the MEMS wafer and the substrate, can be omitted. Therefore, the height of the MEMS wafer can be reduced, and etching processes, particularly DRIE etching, can be avoided during MEMS wafer fabrication. This simplifies the manufacturing process and makes it more cost-effective.

[0014] The substrate can be a ceramic substrate. The substrate can contain aluminum oxide or consist of layers of aluminum oxide. The substrate can be manufactured using additive manufacturing processes, such as 3D printing. The thermal conductivity of the ceramic substrate can be higher than that of the circuit board, allowing heat to be rapidly dissipated from the MEMS chip.

[0015] A MEMS chip can be a MEMS mirror. A MEMS chip can contain or be a MEMS-based acoustic device, such as a microphone, ultrasonic sensor, or speaker. Additionally, a MEMS chip can also contain or be a MEMS-based device for measuring physical parameters, such as a pressure sensor, temperature sensor, light sensor, radiation sensor, or magnetic field sensor. A MEMS chip can be an inertial sensor, such as an accelerometer, vibration sensor, tilt sensor, or gyroscope. A MEMS chip can also contain or be an optical device, such as an image sensor, reflective element, scanning element, interferometer, or miniature laser communication terminal scanning system. Additionally, a MEMS chip can contain or be a device for measuring chemical parameters, such as a hydrogen sensor, gas sensor, biosensor, glucose sensor, or lab-grown sensor.

[0016] MEMS chips can contain one or more movable elements, one of which can be a movable mirror element. MEMS chips can also contain electrical connections, through-hole vias (TSVs), and active and passive components. These components can be directly integrated into the MEMS chip. For example, overvoltage protection components can be directly integrated into the MEMS. This could be a PN diode, for example.

[0017] Electronic components may include a driving element, a movable element designed to move the MEMS wafer. Electronic components may be coated onto the MEMS wafer as an additional layer. Electronic components may include a piezoelectric actuator. These electronic components may also include NTCs, capacitors, or inductors. A MEMS wafer may contain multiple electronic components, with at least one electronic component arranged on the side of the MEMS wafer facing the substrate. Multiple electronic components may be arranged on the side of the MEMS wafer facing the substrate. All electronic components of the MEMS wafer may be arranged on the side of the MEMS wafer facing the substrate.

[0018] The MEMS chip may have electrical contacts on the side facing the substrate, which are connected to electrical contacts on the substrate. The electrical contacts of the MEMS chip and the substrate may each have pads, and the electrical contacts of the MEMS chip and the substrate are interconnected by solder balls.

[0019] Electrical contacts of a MEMS chip can be arranged on the bottom of the MEMS chip facing the substrate and on the side of the MEMS chip perpendicular to the substrate. Therefore, the electrical contacts of the MEMS chip can be L-shaped in cross-section. By arranging the contacts on the bottom facing the substrate and the vertical side, contacts can be formed over a particularly large area and reliable contact can be ensured.

[0020] Electrical contacts of the MEMS wafer can be connected to electrical contacts of the substrate via solder balls. The MEMS wafer can have a movable element, particularly a movable mirror element, where the height of the solder balls can be selected so that the movable element does not collide with the substrate during movement. Even when the movable element deflects to its maximum deflection in its rest position, the solder balls positioned between the substrate and the MEMS wafer prevent the movable element from contacting the substrate. Therefore, the solder balls can act as spacers, eliminating the need for additional spacers or a second silicon layer, which would otherwise be used to maintain the distance between the movable element and the substrate. By using solder balls of sufficient height, MEMS wafers containing only a single layer of silicon can be used. The solder balls can be designed to form a cavity between the movable element in its rest position and the upper surface of the substrate below it, ensuring a distance of at least 300 micrometers between the movable element in its rest position and the upper surface of the substrate. This cavity can have a bottom area of ​​1 square millimeter, and the bottom area is parallel to the substrate.

[0021] The substrate may have a through-hole through which an electrical contact of the substrate is connected to an external electrical contact located on the side of the substrate away from the MEMS wafer. Alternatively or additionally, the substrate may have a wire through which a contact of the substrate is connected to an external electrical contact located on the upper surface of the substrate facing the MEMS wafer or on a side of the substrate perpendicular to the upper surface.

[0022] Both through holes and wires can be sealed or semi-sealed electrical connections.

[0023] The electrical contacts of a MEMS chip can be surrounded by a groove in the MEMS chip. This groove can completely penetrate the material of the MEMS chip. The groove can, for example, surround the electrical contact on three sides, while the fourth side of the electrical contact is not surrounded by the groove.

[0024] The slot ensures that the MEMS wafer is configured as a spring suspension in the electrical contact area. In this case, the area of ​​the MEMS wafer surrounding the electrical contact point has greater deformability than the active area containing electronic components. When a preload is applied to the MEMS wafer, for example due to the different coefficients of thermal expansion of the substrate and the MEMS wafer, the spring suspension formed by the slot ensures that the MEMS wafer deforms only in the electrical contact area, while the active area containing electronic components (which may also contain movable elements) deforms little or no.

[0025] MEMS chips can make electrical contact with the substrate via wire bonding. Wire bonding is an alternative to the flip-chip method.

[0026] MEMS chips can comprise a single silicon layer. MEMS chips can also comprise at least one layer of a material composed of glass, aluminum oxide, diamond, steel, silicon nitride, silicon carbide, polycrystalline silicon, aluminum nitride, or boron nitride. In particular, MEMS chips can be fabricated from a wafer consisting of a single silicon layer. Therefore, the use of an SOI wafer can be omitted.

[0027] A stress relief layer can be disposed between the substrate and the MEMS wafer. The stress relief layer is designed to alleviate mechanical stress that may arise due to the different coefficients of thermal expansion of the substrate and the MEMS wafer. The stress relief layer can be disposed between the upper surface of the substrate and the electrical contacts formed on the substrate, or between the lower surface of the MEMS wafer and the electrical contacts on the MEMS wafer. Furthermore, a first stress relief layer can be disposed on the substrate, and a second stress relief layer can be disposed on the MEMS wafer.

[0028] The substrate can have a spacer on the side facing the MEMS wafer, to which the MEMS wafer contacts. This spacer can adjust the distance between the upper surface of the substrate and the lower surface of the MEMS wafer. The height of the spacer is sufficient to prevent movable elements of the MEMS wafer, particularly movable mirror elements, from impacting the upper surface of the substrate, even at their maximum offset position. By using the spacer, a package can be constructed that eliminates the need for recesses on the upper surface of the substrate or openings through the substrate. The spacer can be designed to form a cavity between the stationary movable element and the upper surface of the substrate below the movable element, ensuring a distance of at least 300 micrometers between the stationary movable element and the upper surface of the substrate. This cavity can have a bottom area of ​​1 square millimeter.

[0029] The substrate may have a recess on the side facing the MEMS wafer, above which movable elements of the MEMS wafer are disposed. Alternatively, the substrate may have an opening through the substrate, above which movable elements are disposed. The recess or opening may be designed such that the movable elements do not strike the substrate during their maximum offset.

[0030] The package may also include a layer of encapsulation material that, together with the substrate, encapsulates a cavity in which the MEMS chip is disposed. The encapsulation material may include a frame surrounding the MEMS chip. The encapsulation material may have a window that covers an opening in the frame or an opening in the substrate.

[0031] The cavity can be sealed with encapsulation material. Therefore, the MEMS wafer within the cavity is protected from moisture, such as water vapor or other ambient gases. This protects the MEMS wafer from corrosion, oxidation, and aging of the optical and electroactive components. The hermetically sealed encapsulation also prevents moisture from condensing within the cavity due to temperature fluctuations.

[0032] MEMS chips can contain sensitive moving components, especially movable mirror components. The package provides mechanical protection to safeguard these moving components during assembly and manufacturing.

[0033] Packages can be designed to keep the cavity optically accessible. For example, a portion or the entire package can be transparent to light beams in the visible spectrum.

[0034] Packages can be designed to suit applications. For example, a package can be designed to withstand a variety of media.

[0035] The package may have an optically transparent window. This window may be made of or contain glass, for example. Alternatively, the window may be made of or contain transparent plastic. The window may have an anti-reflective coating, which ensures that laser beams directed towards the window are almost entirely or minimally reflected.

[0036] When the movable element is stationary, the window can form an angle of 5° to 20° with the surface of the movable element of the MEMS chip. The window is tilted relative to the movable element to ensure that even reflected laser beams do not interfere with the signal laser beam, because the propagation direction of the signal laser beam is different from that of the beam reflected at the window.

[0037] The package can have two optically transparent windows. These two windows can be tilted relative to each other, forming an angle between 10° and 170°. Alternatively, the two windows can be parallel and opposite to each other.

[0038] Additive manufacturing processes, particularly 3D printing, can be used to fabricate parts or the entire package. Compared to traditional ceramic manufacturing processes, additive manufacturing offers greater design flexibility. For example, the substrate can be constructed to be curved. During additive manufacturing, a tilted area of ​​the substrate can be manufactured as a mounting foot for the package. Therefore, the individual elements of the package can be aligned with each other at almost any angle and aligned with the circuit board. Additive manufacturing can also manufacture the substrate and package in a single manufacturing step, eliminating adhesive connections between individual components. The electrical structure of the substrate, especially wires, vias, and electrical contacts, can also be manufactured using additive manufacturing.

[0039] The electronic component may include a piezoelectric actuator, or may be a piezoelectric actuator. The actuator may be designed as a movable element that moves the MEMS wafer. For example, the actuator may be designed to cause vibration of a movable mirror element.

[0040] MEMS wafers may specifically include a MEMS micromirror with a movable mirror element. The movable mirror element may have a reflective layer on the side of the MEMS wafer facing the substrate. Alternatively or additionally, the movable mirror element may have a reflective layer on the side of the MEMS wafer away from the substrate.

[0041] The movable mirror element may have a mechanical reinforcement structure on the side facing away from the reflective layer. This reinforcement structure may include beams. The mechanical reinforcement structure can be formed by thickened portions of the movable mirror element. These thickened portions may be beam-shaped. These beams may be straight or curved.

[0042] By mechanically reinforcing the structure, mirror elements can be designed to undergo only minor deformation, or even no deformation, even under high-amplitude vibrations.

[0043] MEMS chips, including movable elements, may contain integrated photosensitive or acoustic pressure-sensitive electronic components that can measure the offset of mirror elements. Magnetic or electrostatic charging elements (triboelectric effect) on the movable elements may also generate electromagnetic signals that can be measured using sensors on the substrate.

[0044] An ASIC, a laser module, and / or driving electronics for controlling the laser module can be arranged on the substrate. These components can be mounted on the upper surface facing the MEMS wafer or on the lower surface away from the MEMS wafer. These components can be located inside or outside a closed cavity.

[0045] Furthermore, photosensitive or acoustic pressure-sensitive components can be arranged on the substrate. These components can measure the offset and position of the movable elements of the MEMS chip. Similarly, the offset of the movable elements of the MEMS chip can also be measured by inductive or capacitive sensors on the substrate. These sensors measure the electromagnetic field generated by the magnetic or electrostatic charging elements on at least one movable element.

[0046] The laser module can be designed to emit a laser beam. The laser module may include one or more laser diodes. The ASIC can be designed to control the MEMS chip. To this end, the ASIC can send control signals to the driving elements of the MEMS chip.

[0047] At least one optical element, such as a mirror or lens, can be arranged on the substrate. Each optical element can be arranged on the upper or lower surface of the substrate. These optical elements can be located inside or outside a closed cavity.

[0048] At least one sensor may be disposed on the substrate. The sensor may be disposed within an enclosed area or outside. Multiple sensors may be disposed on the substrate.

[0049] A microfluidic channel can be formed within the substrate. This microfluidic channel can be fabricated using an additive manufacturing process. Such channels can be formed relatively easily during additive manufacturing.

[0050] The package can be designed to pump liquids, such as water or glycol, through microfluidic channels to control the temperature of MEMS wafers and / or other components. Other components could be, for example, laser modules. Since MEMS wafers and laser modules generate heat during operation, cooling via microfluidic channels is beneficial.

[0051] The substrate can have a mounting foot designed to attach the substrate to a circuit board, and this mounting foot can be angled to the MEMS wafer, allowing the package to be fixed to the circuit board at an angle between the MEMS wafer and the circuit board. In particular, the mounting foot can be manufactured using additive manufacturing processes, enabling elements to be arranged relative to each other at virtually any angle. The addition of the mounting foot facilitates the angled positioning of the MEMS wafer and / or window relative to a light source (e.g., a laser module).

[0052] The substrate can be curved. If the substrate is curved, the MEMS wafer can be arranged at an angle relative to the light source. The curvature in the substrate can be formed by an additive manufacturing process.

[0053] In one embodiment, the package may include a means for aligning the package, the means being designed to move, for example, tilt, the substrate relative to the support. The means may include a flexible membrane, a microfluidic pump, and / or a piezoelectric actuator.

[0054] At least one actuator, particularly a piezoelectric actuator, may be arranged on a substrate and designed for moving a MEMS wafer. The actuator arranged on the substrate can complement or replace on-chip driving elements (e.g., piezoelectric actuators) of the MEMS wafer. The on-chip actuator can be designed to induce oscillating motion, such as lissajous vibration, in the movable elements of the MEMS wafer.

[0055] MEMS wafers may have a movable element. The package may include a device for determining the offset of the movable element.

[0056] An apparatus for determining the offset of a movable element may include a photosensitive element. The package may be designed such that the amount of light incident on the photosensitive element depends on the offset of the movable element, and the offset of the movable element is determined by evaluating a measurement signal received by the photosensitive element. The photosensitive element may be designed to generate a sensing signal when illuminated by a light beam, and the photosensitive element is connected to an evaluation unit designed to determine the offset of the movable element from the sensing signal measured by the photosensitive element. The apparatus may also include multiple photosensitive elements as described above.

[0057] A photosensitive element can be arranged on a movable element. The arrangement of the photosensitive element allows a light beam deflected by the movable element to reach the photosensitive element. The movable element can be at least partially transparent to light within a certain wavelength range, and the photosensitive element can be arranged on a substrate so that a light beam passing through the movable element can reach the photosensitive element.

[0058] The package may include a light source that emits a measurement laser beam, the arrangement of which allows the measurement laser beam to illuminate a movable element, wherein the deflection of the movable element is determined by measuring the deflection of the measurement laser beam by the movable element. The measurement laser beam may be incident at an angle different from the optical beam path. The deflection of the measurement laser beam may be measured by a photosensitive element.

[0059] The photosensitive element can be arranged in the packaged area, and the movable element reflects the laser beam into the area during the measurement of different offsets.

[0060] The measurement laser beam can enter the package from either the top or bottom.

[0061] The device for determining the offset of a movable element may include an acoustic pressure-sensitive sensor located on a MEMS wafer or substrate.

[0062] The movable element may include an electronic component that is charged by movement in the air, wherein the means for determining the offset of the movable element includes an inductive or capacitive sensor designed to measure the electric field generated by the electronic component that is charged by movement in the air. The inductive or capacitive sensor may be disposed on a substrate, on a MEMS chip, or integrated into a MEMS chip.

[0063] Another aspect relates to a method for manufacturing multiple packages. These packages can be those described above. Therefore, each structural or functional feature associated with a package can also be applied to a package manufactured by this method.

[0064] The method includes the following steps: • Multiple MEMS chips are attached to a single wafer. Each MEMS chip has an electronic component on one side, and the MEMS chips are arranged on the wafer such that the side containing the electronic component faces the wafer. • Separating the wafers, and • The package is encapsulated using an encapsulation material that, together with the substrate, encapsulates a cavity containing a MEMS chip. This step is performed after wafer separation.

[0065] Therefore, the plan is to package the MEMS wafers into a single package only after wafer separation. This method is also known as die-level packaging. Packaging the MEMS wafers before wafer separation is called wafer-level packaging.

[0066] Wafer-level packaging has the following drawbacks when using large optical MEMS chips. In wafer-level packaging, defective MEMS chips are also packaged and then screened out after separation. This leads to significant scrap costs, especially for large and complex MEMS chips, which can be avoided by post-separation packaging.

[0067] During wafer-level packaging, the wafer may undergo deformation (warping), which reduces the quality of the package. This deformation can be avoided if packaging is performed at the die level.

[0068] The installation and handling of wafer-level packaging is much more complex than that of die-level packaging.

[0069] In die-level packaging, MEMS chips can be arranged closer together on the wafer before separation because there is no need to reserve extra space for the housing structure. Simple Explanation of the Diagram

[0070] The preferred implementation method will now be described with reference to the illustrations.

[0071] Figures 1 to 32 show schematic diagrams of packages or packaged components.

[0072] Figures 33 to 38 show photographs of the package at different stages of its manufacturing process and after it has been mounted onto a circuit board.

[0073] Figure 39 schematically illustrates a method for manufacturing a package.

[0074] Figures 40 to 49 illustrate various embodiments of the package. Implementation

[0075] Figure 1 shows a first embodiment of a MEMS chip 1. The MEMS chip is a microelectromechanical mirror. Figure 1 provides a perspective view of the bottom of the MEMS chip.

[0076] MEMS wafer 1 includes a mirror element 2, which is connected to a drive element 3 via two first spring elements 4. The drive element 3 is connected to a rigid region 5 of MEMS wafer 1 via two second spring elements 6. The rigid region 5, drive element 3, mirror element 2, and spring elements 4 and 6 are integrally formed from a common substrate (e.g., silicon), particularly through etching of the common substrate. Furthermore, electrical contacts are arranged on the rigid region 5 of the MEMS wafer.

[0077] A reflective layer 21 (e.g., metal) is coated on the mirror element 2, which is designed to at least partially reflect light in the visible spectrum. The mirror element 2 has a mirror suspension structure 22 that is directly connected to the first spring element 4. The mirror suspension structure 22 is specifically designed to reduce surface deformation of the mirror element 2 during operation of the microelectromechanical mirror 1.

[0078] The drive element 3 has an extended elliptical ring shape with a short axis SA and a long axis LA perpendicular to it. In its rest position, the drive element 3 completely surrounds the mirror element 2 within its main extending plane. A first spring element 4 is disposed on the opposite side of the mirror element 2 along the long axis LA, while a second spring element 6 is disposed on the opposite side of the drive element 3 along the short axis SA. The first spring element 4 and the second spring element 6 are configured as torsion spring elements.

[0079] A piezoelectric layer is coated on the substrate of the driving element 3. This piezoelectric layer may be made of, for example, PZT, AlN or BFO-BT, and is located between two metal electrode layers. At least one of the electrode layers is segmented and has a first driving region 31a, 31b and a second driving region 32a, 32b that are electrically isolated from each other.

[0080] During the operation of the MEMS wafer 1, when an AC voltage is applied to the first driving regions 31a and 31b, a time-periodic mechanical strain is generated in the piezoelectric layer, thereby resonantly exciting the first vibration mode of the mirror element 2. The first vibration mode includes the torsional vibration of the mirror element 2 about a first axis of rotation, which corresponds to the major axis LA.

[0081] During the operation of the microelectromechanical mirror 1, when an AC voltage is applied to the second driving regions 32a and 32b, a time-periodic mechanical strain is also generated in the piezoelectric layer, thereby resonantly exciting the second vibration mode of the mirror element 2. The second vibration mode includes the torsional vibration of the mirror element 2 about the second axis of rotation, which corresponds to the short axis SA.

[0082] The oscillation frequencies of the torsional vibrations of mirror element 2 about its short axis SA and long axis LA correspond to the resonant frequencies of the two vibration modes, respectively, and are different from each other. Therefore, during operation, the laser beam reflected by mirror element 2 can produce, for example, a Lissajous pattern on the projection surface. The frequency comparison between the two oscillation frequencies is preferably a rational number ratio.

[0083] The width and length of MEMS chips can both be greater than 5 millimeters.

[0084] Figures 2 and 3 schematically illustrate the fabrication of MEMS wafers 1 from SOI wafers (SOI = silicon insulator).

[0085] The SOI wafer has a first silicon layer 7, which is used to fabricate the movable structure of the MEMS chip. In addition, the SOI wafer also has a second silicon layer 8, which is separated from the first silicon layer 7 by an etch stop layer 9. The second silicon layer 8 can be used to process the MEMS chip 1 during the manufacturing process. The thickness of the second silicon layer 8 is greater than that of the first silicon layer 7. The etch stop layer 9 can be a silicon oxide layer.

[0086] Electrical contacts 10 of the MEMS wafer 1 are arranged on the side of the first silicon layer 7 facing away from the second silicon layer 8. The electrical contacts 10 can be solder pads. The finished MEMS wafer 1 can be connected to the substrate 11 via the electrical contacts 10. The side of the MEMS wafer 1 where the electrical contacts 10 are located will be referred to as the lower surface below. Additionally, the driving element 3 and the reflective layer of the MEMS wafer 1 can be arranged on the lower surface.

[0087] MEMS wafer 1 is manufactured through an etching process, in which the second silicon layer 8, the etch stop layer 9, and a portion of the first silicon layer 7 are removed to form independent movable structures from the first silicon layer 7. In this way, movable mirror elements 2, spring elements 4 and 6, and an area on the first silicon layer 7 where drive elements 3 are arranged can be formed. Figure 2 shows MEMS wafer 1 before the etching process, while Figure 3 shows MEMS wafer 1 after the etching process.

[0088] The driving element 3 can be a piezoelectric actuator, coated as an additional layer on the MEMS wafer 1. The driving element 3 is placed on the movable element 2.

[0089] When the MEMS wafer is designed to use wire bonding for contact, the drive element 3 can be coated on the side of the movable element 2 away from the electrical contact point 10 (see Figure 4). When the MEMS wafer is designed to use flip-chip interconnect, the drive element 3 can be applied to the side of the movable element 2 where the electrical contact point 10 is located (see Figure 5).

[0090] Figure 4 illustrates how the MEMS chip 1 in Figure 3 is fixed to the substrate 11. The MEMS chip 1 is fixed to the substrate 11 by an adhesive layer 12. The adhesive layer 12 connects to one side of the second silicon layer 8, which is away from the first silicon layer 7 and faces the substrate. The electrical contacts 10 of the MEMS chip 1 are arranged on the side away from the substrate 11. The driving elements are arranged on the side of the MEMS chip 1 facing the substrate 11.

[0091] The substrate 11 has internal and external electrical contacts 13 and 14. The internal electrical contact 13 refers to the electrical contact of the substrate 11 that is electrically connected to the contact 10 of the MEMS wafer 1. The internal electrical contact 13 of the substrate 11 can be packaged together with the MEMS wafer 1 in a cavity. The internal electrical contact 13 of the substrate 11 is located on the upper surface of the substrate 11 facing the MEMS wafer 1. The internal electrical contact 13 of the substrate 11 may include bonding pads.

[0092] The external electrical contacts 14 of the substrate 11 are designed for connection to a circuit board or an external power supply. The external contacts 14 can be connected to the internal contacts 13 via wires and / or through-holes. The external electrical contacts 14 of the substrate 11 may include solder pads.

[0093] In the embodiment shown in Figure 4, the internal electrical contact 13 is arranged on one side of the MEMS wafer 1. The electrical contact point 10 of the MEMS wafer 1 is connected to the internal electrical contact 13 of the substrate 11 via bonding wire 15.

[0094] A frame, which is part of the package, is also arranged on the substrate, and the package material encapsulates the MEMS chip. Because an area on one side of the MEMS chip must be reserved for electrical contacts with the substrate, the frame cannot be placed directly next to the MEMS chip.

[0095] In the embodiment shown in Figure 4, the second silicon layer 8 forms a cavity beneath the movable element 2 of the MEMS wafer 1. This cavity ensures that the movable element 2 can move freely, and in particular, will not impact the substrate 11.

[0096] Figure 5 illustrates another embodiment of the MEMS chip 1 attached to the substrate 11 in Figure 3. In Figure 5, the MEMS chip 1 is attached to the substrate 11 via a flip-chip method. Therefore, the MEMS chip 1 is attached to the substrate 11 such that the bottom of the MEMS chip 1 (the side where the electrical contact 10 and the driving element 3 are located) faces the substrate 11.

[0097] In the embodiment shown in FIG5, the internal electrical contact 13 of the substrate 11 is arranged on the upper surface of the substrate 11 facing the MEMS wafer 1, and is located directly below the electrical contact point 10 of the MEMS wafer 1.

[0098] The electrical contact 10 of the MEMS chip 1 and the internal electrical contact 13 of the substrate 11 are connected by solder balls 16. The solder balls 16 may contain tin or be made of tin.

[0099] The area next to the MEMS wafer 1 does not require internal electrical contacts 13 for the substrate 11. Therefore, the frame 17 can be placed directly next to the MEMS wafer as shown in Figure 6.

[0100] The substrate 11 shown in Figure 5 also has an opening 18 through the substrate 11. The arrangement of the MEMS chip 1 on the substrate 11 is such that the movable element 2 is located above the opening 18. The substrate 11 shown in Figure 6 has a groove 19 on its upper surface, which is located below the movable element 2 of the MEMS chip 1. The groove 19 does not penetrate the entire thickness of the substrate 11.

[0101] The opening 18 in the substrate 11 and the groove 19 on the upper surface of the substrate 11 ensure sufficient space for the movement of the movable element 2. This prevents the movable element 2 from making mechanical contact with the substrate 11. When the MEMS chip 1 is attached to the substrate 11 in a flip-chip configuration, the function of forming a cavity under the movable element 2 previously performed by the second silicon layer 8 can be realized through the opening 18 or the groove 19 in the substrate 11.

[0102] In a further embodiment, this function can be performed by spacers 20 or solder balls 16 arranged between substrate 11 and MEMS wafer 1 (see Figures 15 and 16).

[0103] Compared to the solution in Figure 4, where the MEMS chip 1 is fixed to the substrate 11 using a flip-chip structure, the solution in Figures 5 and 6, which is fixed by bonding wire 15, has the following advantages in addition to the aforementioned advantages of reducing the space required on one side of the MEMS chip 1 and omitting the second silicon layer 8:

[0104] By using flip-chip technology, the length of electrical paths can be reduced, thus reducing signal transmission delays compared to contacts via bonding wires 15. This improves the performance of MEMS chips in terms of speed and signal integrity.

[0105] The flip-chip structure allows heat to be dissipated from the MEMS wafer 1 to the substrate 11 more efficiently than through bonding wire 15. This improves thermal management of the package and helps prevent overheating.

[0106] The flip-chip construction allows the electrical contacts 13 of the substrate 11 to be arranged more closely than when connected using bonding wires 15. This can increase input / output capacity.

[0107] Figure 7 shows a MEMS chip 1 fixed on a substrate 11 according to another embodiment. The MEMS chip 1 shown in Figure 7 is also attached to the substrate 11 by flip-chip technology.

[0108] In this further embodiment, the MEMS wafer 1 is made of a single silicon layer 7. Therefore, the MEMS wafer 1 does not have an etch stop layer 9, nor does it have a second silicon layer 8. Consequently, the height of the MEMS wafer 1 is significantly lower than that of the MEMS wafer 1 shown in FIG. 5.

[0109] Since a second silicon layer 8 is not required to form a cavity beneath the movable element 2 in flip-chip bonding, it can be omitted. Therefore, the use of SOI wafers to fabricate the MEMS chip 1 can be avoided. Instead, the MEMS chip can be fabricated from a wafer with a single silicon layer 7. Therefore, the height of the device can be reduced. Furthermore, since wafers made with a single silicon layer are less expensive than SOI wafers, cost savings can be achieved.

[0110] Furthermore, the manufacturing process can be simplified by omitting the etching process of the second silicon layer 8. Since the second silicon layer 8 is typically thicker, its etching process is a DRIE (Deep Reactive Ion Etching) process. DRIE processes are very complex and costly because they require specific equipment, such as inductively coupled plasma etching machines. Additionally, DRIE processes are slow, resulting in longer processing times. Moreover, DRIE processes are prone to errors, leading to a significant amount of waste. Therefore, omitting the DRIE process can significantly improve the manufacturing process.

[0111] In the embodiment shown in FIG7, the opening 18 is located below the movable element 2 of the MEMS wafer 1 and penetrates the substrate 11. Alternatively, a groove 19 may be formed on the upper surface of the substrate 11.

[0112] Figure 8 shows a detailed view of the MEMS wafer 1 fixed on the substrate 11, as shown in Figure 6. The substrate 11 is a ceramic substrate. It may contain aluminum oxide or be made of aluminum oxide. The substrate 11 may have a multilayer structure, in which wires are integrated into the substrate 11. The substrate 11 can be manufactured by an additive manufacturing process.

[0113] On the upper surface of the substrate 11 facing the MEMS chip 1, the internal electrical contacts 13 of the substrate 11 are formed in the form of solder pads. A metallization layer 23, also known as a "bump under metallization layer", is disposed on the upper surface of the solder pads 13 of the MEMS chip 1.

[0114] The internal electrical contact 13 of the substrate 11 is connected to the external electrical contact 14 on the bottom of the substrate 11 through a through hole 24 extending through the substrate 11. The external electrical contact 14 on the bottom of the substrate 11 is designed to connect the substrate 11 to a circuit board or an external power supply.

[0115] A stress relief layer 25 is disposed between the internal electrical contact 13 of the substrate 11 and the upper surface of the substrate. The stress relief layer is made of a polymer or other dielectric material (e.g., silicon nitride). The stress relief layer 25 is configured to alleviate the mechanical stress between the substrate 11 and the MEMS wafer 1, which are connected by solder joints.

[0116] On the lower surface of the MEMS wafer 1 facing the substrate 11, the electrical contacts 10 of the MEMS wafer 1 are formed in the form of solder pads. On the side facing the substrate 11, a metallization layer 23, also known as a "bump under metallization layer", is disposed on the electrical contacts 10. The electrical contacts also extend laterally along the solder pads and continue along the lower surface of the MEMS wafer 1.

[0117] Another stress relief layer 25 is disposed between the MEMS wafer 1 and the electrical contact 10 forming the bonding pad. This additional stress relief layer 25 is designed to alleviate the mechanical stress between the MEMS wafer 1 and the substrate 11.

[0118] In an alternative embodiment, the stress relief layer 25 may be disposed only on the substrate 11 or only on the lower surface of the MEMS wafer 1.

[0119] A solder ball 16 is arranged between the electrical contact 10 (formed in the form of a solder pad) of the MEMS chip 1 and the internal electrical contact 13 (also formed in the form of a solder pad) of the substrate 11. The substrate 11 and the MEMS chip 1 are mechanically and electrically connected by the solder ball 16.

[0120] The electrical contacts 10 and 13 on the MEMS chip 1 and the substrate 11, as well as the stress relief layer 25, are surrounded by a welding stop layer 26.

[0121] Figure 9 shows another embodiment, illustrating a detailed view of the MEMS wafer 1 disposed on the substrate 11. Unlike the embodiment shown in Figure 8, the metallization layer 23 in Figure 9 extends not only along the lower surface of the MEMS wafer 1 but also along one side of the first silicon layer 7, which is perpendicular to the lower surface. Therefore, an L-shaped bump undermetallization layer is formed in cross-section.

[0122] The MEMS wafer 1 shown in Figure 9 does not have a stress relief layer 25.

[0123] Figures 10 to 12 illustrate another embodiment of a MEMS wafer 1 fixed on a substrate 11. The electrical contacts 10 of the MEMS wafer 1 (formed in the form of solder pads) are partially surrounded by grooves 27 passing through the MEMS wafer 1. The grooves 27 surround the corresponding electrical contacts 10 on three sides. This configuration causes the MEMS wafer 1 to be spring-suspended in the area of ​​the electrical contacts 10.

[0124] MEMS chip 1 is designed to specifically reduce the mechanical stress associated with the electrical contact points 10 around the slot 27. Areas on MEMS chip 1 without electrical contact points 10, and areas formed by the movable element 2 and the drive element 3, experience almost no mechanical stress.

[0125] Figures 11 and 12 show cross-sections of the MEMS wafer 1 fixed on the substrate 11. In Figure 11, there is no mechanical stress between the substrate 11 and the MEMS wafer 1. Therefore, the MEMS wafer 1 is substantially flat.

[0126] In Figure 12, mechanical stress occurs between the MEMS wafer 1 and the substrate 11 due to their different coefficients of thermal expansion. It can be seen that the area where the electrical contact point 10 is located undergoes significant deformation, while the central area where the movable element 2 is located remains undeformed. By designing spring suspensions at the edge of the MEMS wafer 1, the optically relevant central area of ​​the MEMS wafer 1 can be protected from unnecessary deformation caused by the different coefficients of thermal expansion between the MEMS wafer 1 and the substrate 11.

[0127] Therefore, the spring suspension design of the MEMS wafer 1 can serve as an alternative to the stress relief layer 25 shown in Figures 8 and 9. Alternatively, the spring suspension can also be used in combination with the stress relief layer 25 on the MEMS wafer 1 and / or the substrate 11.

[0128] Figure 13 shows the frame 17 connected to the substrate 11 by adhesive connection 28.

[0129] The substrate 11 has external electrical contacts 14 for further connections, such as to a circuit board or an external power supply. The external electrical contacts 14 are located outside the enclosed area of ​​the MEMS wafer 1 surrounded by the substrate 11 and the frame 17.

[0130] The internal electrical contact 13 of the substrate 11, which is connected to the MEMS chip 1, is connected to the external contact 14 via wires 29. Within the frame 17, the wires 29 are covered by a solder stop layer 26 within the area of ​​the internal electrical contact 13 of the substrate 11. The wires 29 do not extend along the adhesive connection 28. Instead, the wires 29 are located in the internal layer of the substrate 11 within the area of ​​the adhesive connection 28.

[0131] Figure 14 shows a substrate 11 and a frame 17 manufactured by a common additive manufacturing process (e.g., a 3D printing process). During this additive manufacturing process, wires 29 formed in or on the substrate 11, as well as electrical contacts 13 and 14 of the substrate 11, are also manufactured simultaneously.

[0132] Therefore, the adhesive connection 28 between the frame 17 and the substrate 11 can be omitted. The conductor 29 is close to the surface of the substrate 11 and is covered by a thin ceramic layer 30, which is formed on the conductor 29 during additive manufacturing. The conductor 29 is connected to the exposed external electrical contact 14, which is not covered by the thin ceramic layer 30. The additional solder stop layer 26 covering the conductor 29 can be omitted because the additively manufactured thin ceramic layer 30 performs this function. By using the additive manufacturing process, it is possible to avoid arranging the conductor 29 in an inner layer in the area of ​​the adhesive connection 28, and the use of the solder stop layer 26 under the external electrical contact 14 of the substrate 11 can be eliminated.

[0133] Figure 15 shows a package that includes a MEMS chip 1 fixed on a substrate 11. The package also includes a layer of encapsulation material that, together with the substrate, forms a sealed cavity in which the MEMS chip 1 is disposed.

[0134] The encapsulation material includes a frame 17 and a window 33. The frame 17 may be made of ceramic or glass, or contain ceramic or glass. The frame 17 may have the same material as the substrate 11 or the window 33, or be constructed from that material. The coefficient of thermal expansion of the material of the frame 17 is similar to that of the substrate 11, thereby reducing or completely avoiding the generation of mechanical stress.

[0135] Window 33 is transparent to light beams in the visible spectrum, especially laser beams. Window 33 is arranged at an angle to the surface of substrate 11. Window 33 can be made of glass or ceramic material. Alternatively, window 33 can be composed of glass or ceramic material. Substrate 11, frame 17, and window 33 can have the same material. The coefficient of thermal expansion of window 33 is very similar to that of substrate 11 and frame 17.

[0136] The side of window 33 facing into the cavity and / or the outside away from the cavity may have an anti-reflective coating. The window may be made of ceramic material.

[0137] Window 33 is tilted towards the upper surface of substrate 11. When the movable element 2 is stationary, window 33 points towards the movable element 2 of MEMS wafer 1. The angle between window 33 and the upper surface of substrate 11 and the movable element 2 of MEMS wafer 1 can be between 5° and 20°. The tilt of window 33 relative to the movable element 2 of MEMS wafer 1 ensures that the laser beam generated by accidental reflection due to window 33 will not propagate in the same direction as the signal laser beam.

[0138] The enclosure can be sealed in a vacuum or inert gas atmosphere. Therefore, a vacuum or inert gas atmosphere can be maintained inside the cavity.

[0139] Encapsulation protects the MEMS wafer 1 located within the cavity from moisture, humidity, and other environmental influences, thereby preventing corrosion, oxidation, or aging caused by other factors. Furthermore, the sealed encapsulation prevents the condensation of moisture within the cavity.

[0140] The package also includes a spacer 20 disposed between the pad portions of the internal electrical contacts 13 of the substrate 11 and the substrate 11. The internal electrical contacts 13 of the substrate 11 are located on the spacer 20. The spacer 20 increases the distance between the MEMS wafer 1 and the substrate 11. Therefore, it can be ensured that the distance between the movable element 2 of the MEMS wafer 1 and the substrate 11 is large enough to prevent interference from the substrate 11 during movement.

[0141] In the substrate 11, a recess 19 is formed below the movable element 2 of the MEMS wafer 1 to prevent mechanical contact between the movable element 2 and the substrate 11. Therefore, the opening 18 that runs through the entire substrate 11 can be omitted. The height of the spacer 20 can be designed to be high enough to allow the recess in the area where the movable element 2 of the MEMS wafer 1 is located to be omitted in the substrate 11.

[0142] Figure 16 illustrates another embodiment. Here, the MEMS wafer 1 is connected to the substrate 11 via high solder balls 16. These solder balls function the same as the spacers 20 on the surface of the substrate 11 shown in Figure 15. The height of the solder balls 16 is chosen sufficiently so that the movable element 2 of the MEMS wafer 1 does not contact the surface of the substrate 11 even at maximum offset. Therefore, the grooves 19 on the substrate 11 can be omitted.

[0143] Figures 17 and 18 illustrate an embodiment of the package, wherein there is an opening 18 in the substrate 11 that fully penetrates the substrate 11, the opening 18 being formed below the movable element 2 of the MEMS wafer 1. A frame 17 and a window 33 are arranged on the lower surface of the substrate 11 away from the MEMS wafer 1.

[0144] In the embodiment shown in Figure 17, an additional frame 17 is fixed on the upper surface of the substrate 11 (which is also the part that fixes the MEMS chip 1), and an additional substrate 34 is connected to the frame. The encapsulation of the cavity in which the MEMS chip 1 is located is formed by the substrate 11, the frame 17 arranged on the lower surface of the substrate, the window 33 connected to the frame, the frame 17 arranged on the upper surface of the substrate, and the additional substrate 34 connected to the frame.

[0145] A laser beam can enter through window 33 located on the lower surface of frame 17, be reflected by movable element 2 of MEMS wafer 1, and exit again through window 33. For this purpose, the lower surface of movable element 2 is coated with a reflective coating. When movable element 2 is in a stationary position, window 33 is tilted relative to movable element 2. The angle formed between window 33 and the stationary movable element 2 is, for example, 5° to 20°.

[0146] In the embodiment shown in FIG17, the internal electrical contact 13 on the upper surface of the substrate 11 is connected to the external electrical contact 14 located on top of another substrate 34 via the conductor 29 in the substrate 11, the frame 17 and the substrate 35 attached to the frame 17.

[0147] On the side of the MEMS wafer 1 facing the substrate 11, a mechanically reinforced structure 35 for the movable element 2 is formed. This could be, for example, a beam structure to prevent the movable element 2 from deforming during offset. The MEMS wafer 1 is made of an SOI wafer, and the second silicon layer 8 is structured as the reinforced structure 35.

[0148] In the embodiment shown in FIG18, a frame 17 is also arranged on the upper surface of the substrate 11. Instead of the additional substrate 34, the upper part of the frame 17 is closed by a second window 33.

[0149] The encapsulation of the cavity housing the MEMS chip 1 is formed by a substrate 11, two frames 17, and two windows 33. The arrangement of these two windows 33 allows a first laser beam to be directed from the lower surface of the encapsulation to the movable element 2 of the MEMS chip 1. Furthermore, through the window 33 arranged on the upper surface of the substrate 11, a second laser beam can be directed from the upper surface of the encapsulation to the movable element 2 of the MEMS chip 1. One of these laser beams can be a signal laser beam used to generate an image of the movable element 2. The other laser beam can be used to monitor the offset of the movable element 2.

[0150] The movable element 2 has a reflective coating on both its lower surface facing the substrate 11 and its upper surface away from the substrate 11. In the embodiment shown in FIG. 18, the MEMS wafer 1 has a single silicon layer 7.

[0151] Figures 19 to 21 show different ways in which the internal electrical contact 13 of the substrate 11 connected to the MEMS chip 1 is connected to the external electrical contact 14 of the substrate 11. Through the external electrical contact, the substrate 11 can be connected to an external power supply or a circuit board.

[0152] Figure 19 shows a through-hole 24 extending from the upper surface of substrate 11 (on which internal electrical contacts 13 for connection to MEMS wafer 1 are arranged) to the lower surface of substrate 11 (on which external electrical contacts 14 designed for connection to an external power supply or circuit board are arranged).

[0153] Figure 20 shows a wire 29 arranged along the upper surface of substrate 11. The wire 29 extends from an internal electrical contact 13, which is connected to the MEMS wafer 1 and located within an enclosed cavity, and extends through frame 17 to an external region of the cavity. Here, substrate 11 can be connected via external electrical contacts 14, for example, to an external power source. Detailed design of the wire 29 is explained in Figures 13 and 14.

[0154] Figure 21 also illustrates the connection via a wire 29 extending from the cavity along the upper surface of the substrate 11. The wire 29 also extends to the side of the substrate 11 perpendicular to the upper surface. The wire 29 partially extends to the lower surface of the substrate 11, which is away from the MEMS wafer 1. External electrical contacts 14 are formed on the lower surface of the substrate 11 for external connections.

[0155] Figure 22 illustrates another embodiment of the package. The package includes a substrate 11, a MEMS wafer 1 mounted on the substrate 11 in a flip-chip manner, a laser module 36, a driving electronics 37 for controlling the laser module 36, an ASIC 38 designed for controlling the MEMS wafer 1, and optical components such as a mirror 39 and a reflective coating 40.

[0156] The substrate 11 has an opening 18 located next to the MEMS wafer 1, which is sealed by a window 33. The substrate 11, the frame 17, the window 33 that closes the frame 17, and the window 33 that closes the opening 18 in the substrate 11 form a cavity for accommodating the MEMS wafer 1. A reflective coating 40 is applied to the lower surface of the window 33 facing the cavity.

[0157] Laser module 36 is disposed on the lower surface of substrate 11. Driving electronics 37 of laser module 36 is located on the upper surface of substrate 11. Driving electronics 37 is connected to laser module 36 through through-hole 24 penetrating substrate 11. Laser module 36 is designed to emit a laser beam. Laser module 36 may include one or more laser diodes.

[0158] A mirror 39 is arranged on the lower surface of the substrate 11. The arrangement of the laser module 36, mirror 39, and window 33 ensures that the laser beam emitted from the laser module 36 is reflected by the mirror 39 and enters the enclosed cavity through the window 33. The arrangement of the reflective coating 40 within the cavity ensures that it reflects the incoming laser beam toward the movable element 2. The laser beam reflected by the reflective coating 40 will strike the movable element 2 of the MEMS wafer 1 and be reflected by it again. The laser beam reflected by the movable element 2 then exits the enclosed cavity through the window 33.

[0159] The ASIC38 is disposed on the lower surface of the substrate 11 and is connected to the internal electrical contact 13 of the substrate 11, which is connected to the MEMS chip 1, through the through hole 24 penetrating the substrate 11.

[0160] Figure 23 illustrates another embodiment. Compared to the embodiment shown in Figure 22, the laser module 36 is now disposed on the upper surface of the substrate 11, while the driving electronics 37 is disposed on the lower surface of the substrate 11. Additionally, the opening 18 next to the MEMS wafer 1 and the window 33 on the lower surface of the substrate 1 are omitted. The mirror 39 that causes the initial deflection of the laser beam is housed within a closed cavity.

[0161] Figure 24 illustrates another embodiment of the package. In the embodiment shown in Figure 24, a frame 17 is disposed on both the upper and lower surfaces of the substrate 11, and the frame 17 is sealed by a window 33. The frame 17 and the window 33 are transparent to the laser beam. A reflective coating 40 is disposed on the inner side of each of the two windows 33. The opening 18 formed below the movable element 2 in the substrate 11 completely penetrates the substrate 11.

[0162] The package has two laser modules 36, each designed to emit a single laser beam. Within a closed cavity, two fixed, angled mirrors 39 are arranged to deflect these two laser beams. The laser beam emitted from the laser module 36 on the upper surface of the substrate 11 is deflected by the mirrors 39 on the upper surface, strikes the reflective coating 40 on the window 33 of the upper surface, and then illuminates the upper surface of the movable element 2 of the MEMS wafer 1, which has a reflective coating. The laser beam emitted from the laser module 36 on the lower surface of the substrate 11 is deflected by the mirrors 39 on the lower surface, strikes the reflective coating 40 on the window 33 of the lower surface, passes through the opening 18 in the substrate 11, and then strikes the lower surface of the movable element 2 of the MEMS wafer 1, which also has a reflective coating.

[0163] One of these two laser beams can be used as a signal laser beam to generate images. The other laser beam can be used as a sensing laser beam to monitor the position and offset of movable elements.

[0164] Alternatively, the laser module 36 can be arranged within a closed cavity. This embodiment is illustrated in Figure 25. In Figure 25, the MEMS wafer 1, the laser module 36, and optical components, particularly the lens 41 and mirror 39, are all arranged within the closed cavity. The driving electronics 37 and ASIC 38 for the laser module 36 are arranged on the lower surface of the substrate 11, thus outside the closed cavity.

[0165] The driving electronics 37 of the laser module 36 are connected to the laser module 36 through a through-hole 24 penetrating the substrate 11. The laser beam emitted from the laser module 36 first passes through two lenses 41, and then is deflected in a certain way by two fixed mirrors 39 so that it hits the movable element 2 of the MEMS chip 1. The laser beam is reflected from the movable element 2 so that it exits from the enclosed cavity through the window 33.

[0166] Figure 26 illustrates another embodiment in which the package has two parallel windows 33. The first window 33 can be used for light entry, through which a laser beam enters the enclosed cavity, while the second window 33 can be used as a light exit, through which a laser beam exits the enclosed cavity.

[0167] Figure 27 shows another embodiment in which the window 33 is arranged at an angle to the MEMS chip 1.

[0168] In the embodiments shown in Figures 26 and 27, the package disposed on the substrate 11 may be made of glass.

[0169] Figures 28 and 29 illustrate an embodiment with two mutually tilted windows 33. In the embodiment shown in Figure 28, a reflective coating 40 is provided on the inner side of one window 33. In this case, the other window 33 is used for the entry and exit of the laser beam. In the embodiment shown in Figure 29, the window 33 does not have a reflective coating 40. The laser beam enters the enclosed cavity through the first window 33, is reflected by the movable element 2 of the MEMS wafer 1, and exits the enclosed cavity through the second window 33.

[0170] Figure 30 illustrates another embodiment of the package. The substrate 11 and the frame 17 are manufactured using an additive manufacturing process.

[0171] During the additive manufacturing process, a mounting foot 42 is also formed on the substrate 11, enabling it to be fixed to the circuit board. The mounting foot 42 can be arranged at an angle with other components in the package. The mounting foot 42 is tilted relative to the movable element 2 of the MEMS wafer 1 in its rest position, and also tilted relative to the window 33. When the mounting foot 42 is attached to the circuit board, the arrangement angle of the substrate 11 and the MEMS wafer 1 is tilted with respect to the circuit board, that is, the substrate 11 and the MEMS wafer 1 are neither parallel nor perpendicular to the substrate.

[0172] By adding a fixing pin 42 and selecting an appropriate angle between the fixing pin 42 and the substrate 11, any angle between the substrate 11 and the circuit board can be selected. In this way, the substrate 11 and the MEMS chip 1 can be aligned with the laser source at a certain angle, thereby ensuring that the reflection of the laser beam does not propagate in the same direction as the signal laser beam.

[0173] Figure 31 illustrates another embodiment. Here, substrate 11 and mounting feet 42 are manufactured together via an additive manufacturing process. Substrate 11 and mounting feet 42 are arranged at an angle. Other packaged components, such as ASIC 38, are disposed on mounting feet 42. By engaging with mounting feet 42, substrate 11 can be aligned with the circuit board at any angle.

[0174] Figure 32 illustrates another embodiment in which substrate 11 is manufactured by an additive manufacturing process and has a bend 43. In substrate 11, the portion where the MEMS wafer 1 is arranged is tilted relative to another portion of substrate 11 containing laser module 36.

[0175] In this embodiment, the bend 43 performs the function of the fixing foot 42. The bend 43 allows the substrate 11 to be attached to the circuit board in a certain way, such that the MEMS wafer 1 and the window 33 (where the laser beam exits after deflection) are arranged at an angle to the circuit board.

[0176] The package has a two-part cover 44 for replicating the shape of the substrate 11. As in the embodiment shown in FIG25, the laser module 36 and optical components are arranged in a closed cavity.

[0177] Figure 33 shows a perspective view of the package. Figure 33 shows the MEMS wafer 1, substrate 11, frame 17, and window 33. Substrate 11 has a rectangular base area. Frame 17 is annular, with its top surface facing the substrate 11 and tilted. Window 33, attached to frame 17, is at an angle relative to substrate 11. Frame 17 is fixed to substrate 11 by metal bonding. Driving element 3 is arranged on the side of MEMS wafer 1 facing substrate 11. A reflective coating 21 is applied to the side of MEMS wafer facing substrate 11. MEMS wafer 1 is fixed to substrate 11 with a flip-chip structure, and its electrical contacts 10 are connected to internal electrical contacts 10 above substrate 11 by soldering.

[0178] Conductors 29 and electrical contacts 13 and 14 are also arranged on the substrate 11. The substrate 11 has internal electrical contacts 13 located within a closed cavity and external electrical contacts 14 located outside the closed cavity. Conductors (not shown) connect each internal electrical contact 13 to the external electrical contact 14. Mechanical and electrical connections are established between the substrate 11 and the MEMS wafer 1 through the internal electrical contacts 13.

[0179] An annular frame is formed on substrate 11. The frame has a sloping surface that is inclined relative to MEMS wafer 1 and substrate 11. Such a sloping surface can be easily achieved through an additive manufacturing process. Similar shapes are difficult to achieve in conventional manufacturing techniques, at least in the absence of mechanical post-processing or in a single homogeneous part without internal seams.

[0180] Figure 34 illustrates a second embodiment of the package. This package essentially contains the same components as the package shown in Figure 33. In this embodiment, the substrate 11 is circular in shape.

[0181] Additionally, the substrate 11 has first and second internal contact points 13a and 13b, only one of which is marked as a reference numeral for example. The first and second internal contact points 13a and 13b of the substrate 11 are arranged within a closed cavity. These two internal contact points 13a and 13b can realize or facilitate the separation of electrical and mechanical connections. Thus, for example, electrical connection to the MEMS wafer 1 to be mounted can be made primarily or solely through the first internal contact point 13a. Mechanical fixation can be achieved primarily or entirely through the second internal contact point 13b.

[0182] In addition, the substrate includes a position mark 45. Position mark 45 is designed to facilitate the installation (often referred to as "removal and placement") of the component to be installed.

[0183] The following diagrams will show the manufacturing process of this package.

[0184] Figure 35 shows the encapsulation after the solder balls 16 have been applied to the first internal contact point 13a on the left. The right side shows the state in which the MEMS wafer 1 is fixed on the solder balls 16. The MEMS wafer 1 can be fixed by a reflow soldering process, and the positioning of the MEMS wafer 1 during this process needs to take into account the position mark 45.

[0185] Figure 36 shows the package after window 33 is fixed to frame 17. Window 33 is fixed to frame 17 by a metal bonding agent. Furthermore, driving elements are arranged on substrate 11, located outside frame 17. Driving elements include driving electronics for ASIC 38 and laser module 37.

[0186] A sensor 46 is fixed to the substrate 11, located outside the enclosed area. The sensor 46 can be designed to measure acceleration and / or temperature and / or humidity and / or brightness.

[0187] Figure 37 illustrates another embodiment of the package. In this embodiment, a bonding wire 15 is also attached to connect the MEMS wafer 1 to the internal electrical contact 13 of the substrate 11 within the cavity. Additionally, a protective element 47 is disposed within the cavity and electrically connected to the MEMS wafer 1. The protective element 47 can be a varistor or a transient voltage suppressor diode.

[0188] A drive element, such as an ASIC 38, is also disposed within the cavity and connected via bonding wire 15 for contact. Additionally, a sensor 46 is located within the cavity and connected via bonding wire 15. This sensor 46 can be configured to measure pressure, temperature, and / or acceleration.

[0189] Figure 38 shows the package mounted on a circuit board. The circuit board contains circuitry for controlling the MEMS wafer 1 and the laser module. The package is connected to the contact points of the circuit board via two bonding wires 15.

[0190] Figure 39 schematically illustrates the method for manufacturing the above-described package. In the first step S1, a plurality of MEMS chips 1 are fixed onto a wafer. Each MEMS chip 1 has an electrical contact element on one side, and the MEMS chip 1 is attached to the wafer such that the side containing the electrical contact element faces the wafer. In the next step S2, the wafer is separated. In the subsequent step S3, the package is encapsulated by applying an encapsulation material. Therefore, these packages are encapsulated at the die level.

[0191] Figure 40 illustrates a device 48 for alignment packaging. Device 48 is designed to move, particularly tilt, a substrate 11 and the associated MEMS wafer 1 relative to a support 49. For this purpose, device 48 can move the substrate 11 using a flexible membrane, a microfluidic pump, or one or more piezoelectric actuators. The support 49 can, for example, be fixed to a circuit board. Device 48 for alignment packaging allows the substrate 11 and the MEMS wafer 1 to tilt relative to the circuit board.

[0192] Figure 41 illustrates one embodiment in which the driving element 3 of the movable element 2 for moving the MEMS wafer 1 is not disposed on the MEMS wafer 1, but on the substrate 11. The MEMS wafer 1 is directly disposed on the driving element 3, for example, bonded to it by an adhesive. The motion generated by the driving element 3 is transmitted to the MEMS wafer 1 through the adhesive layer 50.

[0193] Figures 42 and 43 illustrate a package designed to determine the offset of movable element 2. Movable element 2 is at least partially transparent at certain wavelengths. A photosensitive element 51 is arranged in the region of substrate 11 located below movable element 2.

[0194] A portion of the light beam directed at the movable element 2 is reflected by the movable element 2. A portion of the light beam directed at the movable element 2 passes through the movable element 2 and is refracted at the two interfaces.

[0195] Figure 42 shows the movable element 2 in a stationary position. A laser beam is directed perpendicularly towards the movable element 2. The portion of the laser beam passing through the movable element 2 is not deflected and strikes the photosensitive element 51 directly.

[0196] Figure 43 shows the movable element 2 in the offset position. The laser beam directed at the movable element 2 partially passes through the movable element 2 and undergoes two refractions. Therefore, the laser beam exiting the movable element 2 is laterally offset in its propagation direction compared to the laser beam directed at the movable element 2. The laser beam strikes the photosensitive element 51 at the laterally offset position.

[0197] The photosensitive element 51 can detect the location hit by the laser beam. This information can be used to determine the offset of the movable element 2.

[0198] Figures 44 and 45 illustrate a package in which the offset of the movable element 2 is also determined by the photosensitive element 51. The photosensitive element 51 is arranged on the side of the movable element 2 facing the light incident window 33. Alternatively, the photosensitive element 51 can be integrated into the movable element 2 or arranged on the side of the movable element 2 facing away from the light incident window 33. The larger area of ​​the laser beam that will hit the photosensitive element 51 depends on the angle between the movable element 2 and the incident laser beam, a situation measured by the photosensitive element 51. This information allows the determination of the offset of the movable element 2. Figures 44 and 45 illustrate the different angles between the movable element 2 and the incident laser beam.

[0199] Figures 46 and 47 illustrate a package in which the offset of the movable element 2 is also determined by the photosensitive element 51. The photosensitive element 51 is arranged in a region of window 33 through which the laser beam deflected by the movable element 2 exits the package. Depending on the offset of the movable element 2, different photosensitive elements 51 may be struck by the deflected laser beam, or no photosensitive element 51 may be struck. It can be determined at what point in time which photosensitive element 51 was struck by the laser beam. With this information, the offset of the movable element 2 can be determined.

[0200] Figure 46 shows the state when the movable element 2 is in its stationary position, in which the deflected laser beam does not hit any photosensitive element 51. Figure 47 shows the state when the movable element 2 is in its offset position, in which the deflected laser beam hits one of the photosensitive elements 51.

[0201] Figure 48 shows a package in which a photosensitive element 51 is arranged inside a window 33. In addition to a signal laser beam 52, a measurement laser beam 53 enters the package. Both laser beams are directed at the movable element 2 and strike it at different angles. The measurement laser beam 53 is reflected from the movable element 2 and, depending on the offset of the movable element 2, strikes one of the photosensitive elements 51. The offset of the movable element 2 can be determined based on the value measured by the photosensitive element 51.

[0202] In the embodiments shown in Figures 42 to 48, the driving element 3 is arranged on the substrate. The driving element 3 can be an actuator, especially a piezoelectric actuator.

[0203] Figure 49 also shows a package in which a measuring laser beam 53 is used to determine the offset of the movable element 2. The measuring laser beam 53 enters through a window 33 disposed on the lower surface of the substrate 11. A signal laser beam 52 enters through another window 33. The signal laser beam 52 enters through a window 33 disposed on the upper frame 17 of the MEMS wafer 1. The package also includes a photosensitive element 51, onto which the measuring laser beam 53 is reflected according to the offset of the movable element 2. The offset of the movable element 2 can be determined based on the value measured by the photosensitive element 51.

[0204] 1: MEMS chips 2: (Modible) Components / Mirror Components 3: Driving components 4: First spring element 5: Rigid area 6: Second spring element 7: First silicon layer 8: Second silicon layer 9: Etching stop layer 10: Electrical contacts of MEMS chips 11:Substrate 12: Adhesive layer 13: Internal contact points of the substrate 13a, 13b: Internal contact points of the substrate 14: External contact points of the substrate 15: Wire bonding 16: Welding ball 17: Framework 18: Opening 19: Depression 20: Spacer 21: Reflective layer 22: Mirror Hanging 23: Metallization 24: Through hole 25: Stress relief layer 26: Welded stop layer 27: slot 28: Adhesive connection 29: Trajectory of the Conductor 30: Thin ceramic layer 31a, 31b: First driving region 32a, 32b: Second driving region 33: Window 34: Additional substrate 35: Mechanically reinforced structure 36: Laser Module 37: Driving electronic devices 38:ASIC 39: Mirror 40: Reflective coating 41: Lens 42: Fixed foot 43: Bending of the substrate 44: Lid 45: Location Marker 46: Sensor 47: Protective Components 48: Alignment device 49: Bracket 50: Adhesive layer 51: Photosensitive element 52: Signal Laser Beam 53: Measuring laser beams SA: short axis LA: Long wheelbase

Claims

1. A package comprising a substrate (11); and a MEMS chip (1), wherein, The MEMS wafer (1) is fixed on the substrate (11); it further includes a device (48) for aligning the package, the device (48) being designed to move the substrate (11) relative to the support (49); and / or at least one actuator (3) is arranged on the substrate (11), the actuator (3) being designed to move the MEMS wafer (1).

2. The encapsulation as described in claim 1, wherein, The MEMS chip (1) includes at least one electronic component (3).

3. The encapsulation as described in claim 2, wherein, The at least one electronic component (3) is arranged on the side of the MEMS wafer (1) facing the substrate, or the at least one electronic component (3) is arranged on the side of the MEMS wafer (1) away from the substrate.

4. The package as claimed in claim 1 includes at least one electronic component (3) disposed on the side of the MEMS wafer (1) facing the substrate, and at least one electronic component (3) disposed on the side of the MEMS wafer (1) away from the substrate.

5. The encapsulation as described in claim 1, wherein, The MEMS chip includes a movable element.

6. The encapsulation as described in claim 5, wherein, The MEMS chip (1) includes at least one electronic element (3), wherein the at least one electronic element (3) is a driving element designed to move the MEMS chip (1).

7. The encapsulation as described in claim 1, wherein, The MEMS chip (1) is fixed on the substrate (11) by flip-chip bonding.

8. The encapsulation as described in claim 1, wherein, The MEMS chip (1) has an electrical contact (10) on the side facing the substrate (11), which is connected to the electrical contact (13) of the substrate (11).

9. The encapsulation as described in claim 8, wherein, The electrical contact points (10) of the MEMS chip (1) are additionally arranged on the side of the MEMS chip (1) perpendicular to the substrate (11).

10. The encapsulation as described in claim 8, wherein, The electrical contact (10) of the MEMS chip is connected to the electrical contact (13) of the substrate (11) via solder balls (16).

11. The encapsulation as described in claim 10, wherein, The MEMS chip includes a movable element, and the height of the solder ball (16) is selected such that the movable element (2) does not collide with the substrate (11) during movement.

12. The encapsulation as described in claim 8, wherein, The substrate (11) has a through hole (24), and an electrical contact (13) of the substrate (11) is connected to an external electrical contact (14) through the through hole (24). The external electrical contact (14) is located on a side away from the MEMS wafer (1), and / or the substrate (11) has a wire (29), and a contact of the substrate (11) is connected to the external electrical contact (14) of the substrate (11) through the wire (29). The external electrical contact (14) is located on the top of the substrate (11) facing the MEMS wafer (1) or on the side of the substrate (11) perpendicular to the top.

13. The encapsulation as described in claim 8, wherein, The electrical contact point (10) of the MEMS chip (1) is partially surrounded by a groove (27) in the MEMS chip (1).

14. The encapsulation as described in claim 13, wherein, The MEMS wafer (1) has a higher deformability in the region of the groove (27) surrounding the electrical contact point (10) than the active region containing the electronic component (3).

15. The encapsulation as described in claim 1, wherein, The MEMS chip (1) is electrically connected to the substrate (11) via bonding wire (15).

16. The encapsulation as described in claim 1, wherein, The MEMS chip (1) contains a single silicon layer (7).

17. The encapsulation as described in claim 1, wherein, A stress relief layer (25) is arranged between the substrate (11) and the MEMS wafer (1).

18. The encapsulation as described in claim 1, wherein, The substrate (11) has a spacer (20) on the side facing the MEMS wafer (1), and the MEMS wafer (1) is in contact with the spacer (20).

19. The encapsulation as described in claim 1, wherein, The substrate (11) has a recess (19) on the side facing the MEMS wafer (1), and a movable element (2) of the MEMS wafer (1) is arranged above the recess (19).

20. The package as claimed in claim 19 further includes a layer of packaging material that, together with the substrate (11), forms a closed cavity in which the MEMS wafer (1) is disposed.

21. The encapsulation as described in claim 1, wherein, The encapsulation material has a window (33).

22. The encapsulation as described in claim 21, wherein, The window (33) has an anti-reflective coating.

23. The encapsulation as described in claim 21, wherein, When the movable element (2) is stationary, the window (33) forms an angle between 5° and 20° with the surface of the movable element (2) in the MEMS wafer (1).

24. The encapsulation as described in claim 1, wherein, The encapsulation material has two windows (33).

25. The encapsulation as described in claim 24, wherein, The two windows (33) form an angle between 10° and 170°.

26. The encapsulation as described in claim 25, wherein, The two windows (33) are positioned opposite each other.

27. The encapsulation as described in claim 20, wherein, At least a portion of the packaging material was manufactured using an additive manufacturing process.

28. The encapsulation as described in claim 1, wherein, The substrate (11) is manufactured by an additive manufacturing process.

29. The encapsulation as described in claim 1, wherein, The electronic component (3) includes a piezoelectric actuator.

30. The encapsulation as described in claim 5, wherein, The MEMS chip (1) includes a MEMS micromirror, and the movable element (2) is a movable mirror element (2).

31. The encapsulation as described in claim 30, wherein, The movable mirror element (2) has a reflective layer disposed on the side of the MEMS wafer (1) facing the substrate (11).

32. The encapsulation as described in claim 30, wherein, The movable mirror element (2) has a reflective layer disposed on the side of the MEMS wafer (1) away from the substrate (11).

33. The encapsulation as described in claim 30, wherein, The movable mirror element (2) has a mechanically reinforced structure (35) on the side away from the reflective layer.

34. The encapsulation as described in claim 1, wherein, An ASIC (38), a laser module (36), and / or a drive circuit (37) for controlling the laser module (36) are arranged on the substrate (11).

35. The encapsulation as described in claim 1, wherein, At least one optical element, such as a mirror (39) or a lens (41), is arranged on the substrate (11).

36. The encapsulation as described in claim 1, wherein, At least one sensor (46) is arranged on the substrate (11).

37. The encapsulation as described in claim 1, wherein, A microfluidic channel is formed in the substrate (11).

38. The encapsulation as described in claim 37, wherein, The package is designed to pump liquids such as water or ethylene glycol through microfluidic channels to control the temperature of the MEMS wafer (1) and / or other components of the package.

39. The encapsulation as described in claim 1, wherein, The substrate (11) has a fixing foot (42) for fixing on the circuit board. The fixing foot (42) is set at an angle to the MEMS chip (1), so that the package can be mounted on the circuit board with the MEMS chip (1) at an angle relative to the circuit board.

40. The encapsulation as described in claim 1, wherein, The substrate (11) has a bend (43).

41. The encapsulation as described in claim 1, wherein, The device (48) includes a flexible membrane, a microfluidic pump and / or a piezoelectric actuator.

42. The encapsulation as described in claim 1, wherein, At least one of the actuators (3) is a piezoelectric actuator.

43. The encapsulation as described in claim 1, wherein, The MEMS chip includes a movable element, and the actuator (3) is designed to move the movable element (2) of the MEMS chip (1).

44. The encapsulation as described in claim 5, wherein, The package includes a device (48) for determining the offset of the movable element (2).

45. The encapsulation as described in claim 44, wherein, The device (48) for determining the offset of the movable element (2) has a photosensitive element (51).

46. ​​The encapsulation as described in claim 45, wherein, The offset of the movable element (2) is determined by evaluating the measurement signal received by the photosensitive element (51).

47. The encapsulation as described in claim 45, wherein, The photosensitive element (51) is arranged on the movable element (2).

48. The encapsulation as described in claim 45, wherein, The photosensitive element (51) is arranged such that a light beam deflected by the movable element (2) shines on the photosensitive element (51).

49. The encapsulation as described in claim 45, wherein, The movable element (2) is at least partially transparent to light within a specific wavelength range, and the photosensitive element (51) is disposed on the substrate (11) such that a light beam passing through the movable element (2) reaches the photosensitive element (51).

50. The package as claimed in claim 44 includes a light source for emitting a measurement laser beam (53), the light source being arranged such that the measurement laser beam (53) illuminates the movable element (2), and the amount of offset of the movable element (2) is determined by measuring the deflection of the movable element (2) of the measurement laser beam (53).

51. The encapsulation as described in claim 50, wherein, The photosensitive element (51) is arranged in the area of ​​the package where the movable element (2) reflects the measuring laser beam (53) at its different offsets.

52. The encapsulation as described in claim 50, wherein, The measuring laser beam (53) can enter from the top or bottom of the package.

53. The encapsulation as described in claim 44, wherein, The device (48) for determining the offset of the movable element (2) includes an acoustic pressure sensitive sensor located on the MEMS wafer (1) or the substrate (11).

54. The encapsulation as described in claim 44, wherein, The movable element (2) has an electronic component that is charged by moving in the air, and the means (48) for determining the offset of the movable element (2) includes an inductor or capacitor sensor designed to measure the electric field generated by the electronic component that is charged by moving in the air.

55. The encapsulation as described in claim 54, wherein, The inductor or capacitor sensor is disposed on the substrate (11) or the MEMS chip (1), or integrated into the MEMS chip (1).

56. The encapsulation as described in claim 1, wherein, The MEMS chip includes a MEMS-based acoustic device such as a microphone, ultrasonic sensor, or speaker.

57. The encapsulation as described in claim 1, wherein, The MEMS chip includes a MEMS-based device for measuring physical parameters, such as a pressure sensor, temperature sensor, light sensor, radiation sensor, or magnetic field sensor.

58. The encapsulation as described in claim 1, wherein, The MEMS chip includes an inertial sensor such as an accelerometer, vibration sensor, tilt sensor, or gyroscope.

59. The encapsulation as described in claim 1, wherein, The MEMS chip includes an optical element such as an image sensor, a reflective element, a scanning element, an interferometer, or a laser scanning communication terminal.

60. The encapsulation as described in claim 1, wherein, The MEMS chip includes a device for measuring chemical parameters such as hydrogen sensors, gas sensors, biosensors, glucose sensors, or laboratory wafer sensors.

61. A package comprising a substrate (11); and a MEMS chip (1), wherein, The MEMS chip (1) is fixed on the substrate (11). The MEMS chip (1) has an electrical contact (10) on the side facing the substrate (11). The electrical contact is connected to the electrical contact (13) of the substrate (11). The electrical contact (10) of the MEMS chip (1) is partially surrounded by a groove (27) in the MEMS chip (1), so that the MEMS chip (1) is designed to be spring-suspended in the area of ​​the electrical contact (13).

62. A package comprising a substrate (11); and a MEMS chip (1), wherein, The MEMS wafer (1) is fixed on the substrate (11), wherein the substrate (11) has a bend (43), and wherein the substrate (11) is manufactured by an additive manufacturing process.

63. A method for manufacturing a plurality of packages, comprising the following steps: • fixing a plurality of MEMS wafers (1) onto a wafer; • slicing the wafer; and • encapsulating the package with a layer of encapsulation material, the encapsulation material and a substrate (11) forming a cavity, wherein, The MEMS wafer (1) is arranged in the cavity, and this step is performed after the wafer is diced.

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