High-efficiency wire leading method for high-temperature MEMS device

Abstract

The invention belongs to the technical field of MEMS lead packaging, and relates to an efficient lead method for a high-temperature MEMS device, which comprises the following steps of: processing a micro through hole penetrating through the high-temperature MEMS device along the vertical direction in a lead area of the high-temperature MEMS device to be led; arranging a wire serving as a lead in the micro through hole, enabling two ends of the wire to be respectively positioned on the upper side and the lower side of the high-temperature MEMS device to be led, and then bending the wire along the lead direction and fixing the wire on the upper side and the lower side of the high-temperature MEMS device to be led; and filling slurry in the lead area and curing to form electrical connection and fix the lead so as to obtain the lead connector. According to the method, lead packaging is carried out on the MEMS device on the whole wafer level, the batch production process is more concise, and the lead packaging efficiency is improved; the advantages of mechanical structure fastening and slurry sintering lead wire are integrated, and the lead wire strength is enhanced; the high-temperature-resistant performance of the whole MEMS device is improved through a mode of firstly leading wires and then integrally arranging the high-temperature-resistant protection layer.

Description

Technical Field

[0001] The invention belongs to the technical field of MEMS lead packaging and relates to a high-efficiency lead method for a high-temperature MEMS device. Background Art

[0002] MEMS stands for Micro Electromechanical System, which is a tiny device that combines mechanical and electronic technologies. It is a product that combines micro-machining technology with semiconductor technology. Due to its miniaturization, low power consumption, integration, and intelligence, MEMS is widely used in various fields to sense motion, sound, temperature, pressure and other signals.

[0003] With the rapid development of science and technology, the demand for MEMS (micro-electromechanical systems) devices working in high-temperature environments is growing. In high-temperature environments, the stability and reliability of devices become key challenges in design. Among them, lead packaging is an important link in connecting the internal and external circuits of the device, and its performance directly affects the performance and life of the entire device. The lead packaging of high-temperature MEMS devices must not only ensure the reliability of electrical connections, but also withstand challenges such as thermal stress and thermal expansion brought by high-temperature environments. At the same time, trends such as multi-parameter integration and miniaturization will also bring new challenges and opportunities to the lead packaging technology of high-temperature MEMS devices. At present, traditional MEMS product lead methods include lead packaging methods such as wire bonding and sintered lead technology based on metal solder, but they still cannot meet the efficient lead packaging needs of high-temperature MEMS products. For example, although wire bonding can achieve small size and automated lead requirements, the lead strength is low and cannot meet the high temperature resistance requirements; the sintered lead method based on metal solder is subject to size restrictions during the wiring and lead process, the production efficiency is low, and the lead strength cannot meet the requirements.

[0004] Based on this, it is necessary to invent an efficient lead packaging method for high-temperature MEMS devices to address the shortcomings of existing methods. Summary of the invention

[0005] In view of this, an object of the present invention is to provide an efficient wiring method for a high temperature MEMS device, which can meet the efficient wiring requirements of the high temperature MEMS device and is of great significance for improving the design mode and manufacturing efficiency of the high temperature MEMS device.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A high-efficiency lead method for a high-temperature MEMS device comprises the following steps:

[0008] Step 1: Processing a micro-through hole that vertically penetrates the high-temperature MEMS device in the lead area of ​​the high-temperature MEMS device to be wired;

[0009] Step 2: Arrange the wire as the lead into the micro-through hole, and make the two ends of the wire be located at the upper and lower sides of the high-temperature MEMS device to be led, and then bend the wire along the lead direction and fix it at the upper and lower sides of the high-temperature MEMS device to be led;

[0010] Step 3: Fill the lead area with paste and cure to form an electrical connection and secure the wire to obtain a lead joint.

[0011] Furthermore, in step 1, the high temperature MEMS device to be wired is arranged on a wafer, and the wafer has a plurality of high temperature MEMS devices to be wired;

[0012] Before processing the micro through-holes, the wafer is first limited and fixed to facilitate the processing of the micro through-holes.

[0013] Further, it also includes step 4 and step 5;

[0014] Step 4: A high temperature protection layer is provided on the entire surface of the wafer to protect the functional layer and lead area of ​​the high temperature MEMS device;

[0015] Step 5: Cut the wafer into bonded units and then split them into multiple high-temperature MEMS devices with completed lead packaging.

[0016] Furthermore, the wafer is limited and fixed by a fixture, and the limiting and fixing method is one of pneumatic, hydraulic, bolt screwing, spring pressing sheet, vacuum adsorption or magnetic adsorption.

[0017] Furthermore, the substrate material of the high-temperature MEMS device is one of aluminum oxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride, boron nitride, silicate or glass, and the sensitive layer material is metals such as nickel and its alloys, tungsten and its alloys, platinum and its alloys, and one or more of indium tin oxide or zinc oxide.

[0018] Furthermore, the micro-through holes are processed by laser processing, and the hole size matches the diameter of the wire used for the lead.

[0019] Furthermore, the material of the wire is one or more of nickel and its alloys, tungsten and its alloys, platinum and its alloys.

[0020] Furthermore, in step 3, the front side of the lead area of ​​the high-temperature MEMS device is filled with a conductive paste, and the back side is filled with a fixing paste.

[0021] Furthermore, in step 4, the high temperature protective layer is formed by a process selected from magnetron sputtering, electron beam evaporation coating or atomic layer deposition.

[0022] Furthermore, in step 5, when wafer cutting is performed, a cutting path is designed according to the size of the high-temperature MEMS device.

[0023] The beneficial effects of the present invention are:

[0024] The high-temperature MEMS device lead method provided by the present invention performs lead packaging on the MEMS device at the overall wafer level, which is more concise in the batch production process and improves the efficiency of lead packaging;

[0025] The lead method combines the advantages of mechanical structure fastening and slurry sintering leads, which enhances the lead strength and improves the lead reliability to a certain extent. By first wiring and then setting a high-temperature protective layer on the whole, the overall high-temperature resistance of the MEMS device is improved.

[0026] Moreover, the lead method can be efficiently produced by an automated assembly line production operation mode, and is a high-efficiency lead packaging method for high-temperature MEMS devices.

[0027] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0029] Figure 1 It is a schematic diagram of the states of the wafer to be wired and the MEMS device in the embodiment;

[0030] Figure 2 This is a schematic diagram of the state of laser drilling a wafer in an embodiment;

[0031] Figure 3 A schematic diagram of wiring a MEMS device in an embodiment;

[0032] Figure 4 A schematic diagram of a state of slurry filling a MEMS device in an embodiment;

[0033] Figure 5 This is a schematic diagram of the state of slurry sintering of a MEMS device in an embodiment;

[0034] Figure 6 A schematic diagram of a state where a high temperature protection layer is provided for a MEMS device in an embodiment;

[0035] Figure 7 A schematic diagram of a state of slicing a MEMS device in an embodiment;

[0036] Figure 8 A schematic diagram of a high-temperature MEMS device with completed leads in the embodiment;

[0037] Fig. 9 A side cutaway diagram of wiring for a single MEMS sensor.

[0038] Fig.10 Schematic side cross-sectional view of a single MEMS sensor after wiring, bending and fixing.

[0039] Figure numerals: 1-wafer; 2-high-temperature MEMS device to be wired; 3-wire area 3; 4-tooling fixture; 41-rotating axis; 42-carrying table; 43-limiting table; 5-laser processing equipment; 6-micro-through hole; 7-wire tooling fixture; 8-wire; 9-glue dispensing equipment; 10-slurry; 11-high-temperature protective layer; 12-high-temperature MEMS device with completed wires. DETAILED DESCRIPTION

[0040] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0041] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0042] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0043] See also Figures 1 to 9 , is a high-efficiency wiring method for high-temperature MEMS devices, comprising the following steps:

[0044] First, the wafer 1 with the prepared sensitive layer is taken out, and the wafer 1 has a plurality of arranged high-temperature MEMS devices 2 to be wired, and the high-temperature MEMS devices 2 to be wired are high-temperature resistant MEMS products, and the base material thereof is aluminum oxide, and the sensitive layer material is nickel and its alloy;

[0045] In other embodiments, the base material includes but is not limited to one of high temperature resistant materials such as magnesium oxide, zirconium oxide, silicon carbide, silicon nitride, boron nitride, silicate, glass, etc., and the sensitive layer material includes but is not limited to metals such as tungsten and its alloys, platinum and its alloys, and oxides such as indium tin oxide (ITO) and zinc oxide (ZnO), and doped conductive oxide solid solution high temperature resistant materials.

[0046] Wafer 1 is placed as a whole in a fixture 4 for position limiting and fixing. The fixture 4 includes a rotating shaft 41, a bearing platform 42 and a position limiting platform 43. The rotating shaft 41 is fixedly connected to the outer side of the bearing platform 42 to rotate the bearing platform 42. The bearing platform is an annular hollow structure for position limiting and fixing wafer 1. The position limiting platform 43 is arranged below the bearing platform, and the position limiting platform 43 has a step structure for limiting the vertical position of the wire 8 during the wiring process and bending the wire 8 when the bearing platform is moved;

[0047] Specifically, a mechanical gripper is used to absorb and grab wafer 1 from the material rack and place it on the designated position of the carrier. After wafer 1 is in place, the mechanical gripper releases the wafer and resets it, and pneumatically tightens the carrier to limit and tighten the wafer, completing the loading and fixing process;

[0048] In other embodiments, the support platform 42 may also adopt different fastening methods such as hydraulic pressure, bolt screwing, spring pressure sheet, vacuum adsorption or magnetic adsorption to limit and fix the wafer.

[0049] A laser processing device 5 is used to process a micro-through hole 6 penetrating through the wafer 1 in a direction perpendicular to the wafer 1 at the lead area 3, and the through hole diameter is 0.25 mm;

[0050] Specifically, the laser power of the laser processing equipment 5 is set to 800 W, the pulse width is 1.5 μs, the laser frequency is 200 Hz, the drilling time is 5 s, the purge gas is compressed air, and the gas pressure is 5 bar.

[0051] A nickel-based alloy compensation wire with the same material as the electrode material of the lead area 3 and a diameter of 0.127 mm is placed in the automatic cutting device. The automatic cutting device moves to a suitable position just above the micro-through hole 6. The automatic cutting device cuts a 5 mm long compensation wire. The compensation wire falls through the micro-through hole 6 and reaches the limit table of the fixture 4. The limit table can ensure that the compensation wire retains a length of 1 mm on the upper plane of the wafer and a length of 3.5 mm on the lower plane. Since the compensation wire passes through the high-temperature MEMS device 2 to be led after it is in place, and the two ends of the compensation wire are respectively located on the upper and lower sides of the high-temperature MEMS device 2 to be led, when the wire fixture 7 on both sides and the limit table of the fixture 4 move along the lead direction, the two ends of the compensation wire in the micro-through hole 6 are bent and fixed under the cooperation of the wire limit fixing fixture 7 and the fixture 4 to form a sideways U-shaped structure;

[0052] Sintered conductive silver paste is set in the dispensing device 9, and the dispensing needle is moved to a suitable position just above the micro-through hole 6 to start dispensing;

[0053] Specifically, the glue dispensing needle size of the glue dispensing device 9 is 30G, the glue dispensing air pressure is 60psi, the glue dispensing time is 3s, and the glue dispensing needle moves along the lead direction while dispensing, and the moving speed is 0.2mm / s, ensuring that the filling slurry 10 achieves effective coverage and does not overflow the lead area, ensuring effective electrical connection between the compensation wire and the MEMS lead electrode;

[0054] The rotating shaft in the fixture 4 rotates 180 degrees, and alumina ceramic slurry is set in the dispensing device 9. The dispensing needle moves to the appropriate position just above the micro-through hole 6 on the back of the MEMS device to start dispensing. The dispensing needle size is 30G, the dispensing air pressure is 60psi, and the dispensing time is 1s. The dispensing needle moves along the direction of the buried wire groove while dispensing, and the moving speed is 0.2mm / s to ensure that the filling slurry 10 is effectively coated and does not overflow the lead area;

[0055] After the slurry filling is completed, the fixture containing wafer 1 is moved to the sintering furnace for sintering and curing. The sintering temperature is 150°C and the sintering time is 1 hour.

[0056] After the slurry is sintered, a high-temperature insulating protective film layer is set on the wafer 1 with completed leads as a high-temperature protective layer 11 for in-situ packaging protection. The high-temperature protective layer 11 is set by electron beam evaporation coating. The material of the high-temperature protective layer 11 is aluminum oxide with a thickness of 1 μm to increase the high-temperature resistance of the high-temperature MEMS device.

[0057] Specifically, the parameters of the electron beam evaporation coating equipment are set to 20% electron beam output power, 3*e-5Torr starting vacuum degree, 150°C coating temperature, and coating rate. Set the oxygen flow rate to 50sccm and the aluminum oxide coating thickness to

[0059] The coated wafer 1 is diced by laser cutting. The cutting path is designed according to the size of the high-temperature MEMS device 2 to be wired. Wafer 1 is cut along the edge of the high-temperature MEMS device, and the wafer is cut into bonded units. Finally, the wafer is split into a single complete wire-packaged high-temperature MEMS device 12.

[0060] Specifically, the laser power is set to 500 W, the laser frequency is 200 Hz, the purge gas is compressed air, the gas pressure is 5 bar, and the cutting speed is set to 20 mm / s.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A high-efficiency lead method for high-temperature MEMS devices, characterized in that: The following steps are involved: Step 1: Processing a micro-through hole that vertically penetrates the high-temperature MEMS device in the lead area of ​​the high-temperature MEMS device to be wired; Step 2: Arrange the wire as the lead into the micro-through hole, and make the two ends of the wire be located at the upper and lower sides of the high-temperature MEMS device to be led, and then bend the wire along the lead direction and fix it at the upper and lower sides of the high-temperature MEMS device to be led; Step 3: Fill the lead area with paste and cure to form an electrical connection and secure the wire to obtain a lead joint.

2. The high-efficiency lead method for high-temperature MEMS devices according to claim 1, characterized in that: In step 1, the high temperature MEMS device to be wired is arranged on a wafer, and the wafer has a plurality of high temperature MEMS devices to be wired; Before processing the micro through-holes, the wafer is first limited and fixed to facilitate the processing of the micro through-holes.

3. The high-efficiency lead method for high-temperature MEMS devices according to claim 2, characterized in that: Also includes steps 4 and 5; Step 4: A high temperature protection layer is provided on the entire surface of the wafer to protect the functional layer and lead area of ​​the high temperature MEMS device; Step 5: Cut the wafer into bonded units and then split them into multiple high-temperature MEMS devices with completed lead packaging.

4. The high-efficiency lead method for high-temperature MEMS devices according to claim 2, characterized in that: The wafer is limited and fixed by a fixture, and the limiting and fixing method is one of pneumatic, hydraulic, bolt screwing, spring pressing, vacuum adsorption or magnetic adsorption.

5. The high-efficiency wiring method for high-temperature MEMS devices according to claim 1, characterized in that: The substrate material of the high-temperature MEMS device is one of aluminum oxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride, boron nitride, silicate or glass, and the sensitive layer material is one or more of metals such as nickel and its alloys, tungsten and its alloys, platinum and its alloys, and indium tin oxide or zinc oxide.

6. The high-efficiency wiring method for high-temperature MEMS devices according to claim 1, characterized in that: The micro-through hole is processed by laser processing, and the hole size matches the diameter of the wire used for the lead.

7. The high-efficiency wiring method for high-temperature MEMS devices according to claim 1, characterized in that: The material of the wire is one or more of nickel and its alloys, tungsten and its alloys, platinum and its alloys.

8. The high-efficiency wiring method for high-temperature MEMS devices according to claim 1, characterized in that: In step 3, the front side of the lead area of ​​the high-temperature MEMS device is filled with a conductive paste, and the back side is filled with a fixing paste.

9. The high-efficiency wiring method for high-temperature MEMS devices according to claim 3, characterized in that: In step 4, the high temperature protection layer is formed by a process selected from magnetron sputtering, electron beam evaporation coating or atomic layer deposition.

10. The high-efficiency wiring method for high-temperature MEMS devices according to claim 3, characterized in that: In step 5, when wafer cutting is performed, a cutting path is designed according to the size of the high-temperature MEMS device.

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