MEMS sensor based on TGV technology and packaging method thereof

Abstract

The invention provides a TGV technology-based MEMS sensor and a packaging method thereof. The TGV technology-based MEMS sensor comprises a grain layer and a glass-based RDL layer which are bonded; the crystal grain layer comprises an MEMS and an ASIC which are heterogeneously integrated, the crystal grain layer is subjected to surface PAD treatment and gold plating treatment, the crystal grain layer is bonded with an anode of the glass-based RDL layer through a surface PAD, and the MEMS and the ASIC are both prepared from a wide bandgap semiconductor material; the glass-based RDL layer comprises a single-layer metallization layer or a multi-layer metallization layer prepared based on a TGV process and an RDL process, and glass is used as a dielectric layer among the multi-layer metallization layers. According to the invention, chip-level integrated packaging can be carried out on each functional unit, various performances are considered, high impedance of an analog interface and miniaturization of a circuit volume are realized, and the use amount of discrete components is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sensors, in particular to a MEMS sensor based on TGV technology and a packaging method thereof. BACKGROUND

[0002] The MEMS (Micro-Electro-Mechanical Systems) sensor is a sensor integrated by micro-electro-mechanical system technology, which has the characteristics of high sensitivity, high accuracy, small size, stable performance, etc., and is widely used in consumer electronics, industrial automation, aerospace, national defense and military industry, etc.

[0003] In some specific occasions, it is required to measure acceleration, attitude angle, temperature, geomagnetic data, etc., and higher requirements are put forward for the sensor and its peripheral circuit, such as high and low temperature resistance (-55℃-155℃), high impedance of analog interface and miniaturization of circuit volume (greatly reducing the amount of discrete components).

[0004] Therefore, there is an urgent need for a MEMS sensor that can perform chip-level integrated packaging of each functional unit, take into account multiple performances, and realize high impedance of analog interface and miniaturization of circuit volume. SUMMARY

[0005] Therefore, it is necessary to provide a MEMS sensor based on TGV technology and a packaging method thereof in view of the above technical problems.

[0006] A MEMS sensor based on TGV technology, comprising the following steps: a bonded die layer and a glass-based RDL layer; the die layer comprises a heterogeneously integrated MEMS and ASIC, the die layer is treated by surface PAD and gold plating, the die layer is anodically bonded to the glass-based RDL layer through the surface PAD, and the MEMS and ASIC are both prepared by using wide-bandgap semiconductor materials; the glass-based RDL layer comprises a single-layer metallization layer or a multi-layer metallization layer prepared based on TGV technology and RDL technology, and glass is used as a dielectric layer between the multi-layer metallization layers.

[0007] In one embodiment, the surface of the MEMS and ASIC is provided with a plurality of PADs for bonding with the glass-based RDL layer, and the surface of the PAD is provided with a gold plating layer.

[0008] In one embodiment, the glass-based RDL layer includes a top metal layer, an intermediate dielectric layer and a bottom metal layer; the top metal layer includes a metallized dielectric made based on TGV technology, which is used to electrically connect the PAD on the MEMS surface to the PAD on the ASIC surface and the packaging substrate or lead frame, and to electrically connect the PAD on the ASIC surface to the PAD on the MEMS surface and the packaging substrate or lead frame; the intermediate dielectric layer is a glass layer; the bottom metal layer includes a metallized dielectric and PAD made based on TGV technology, which are used to connect to the packaging substrate or lead frame through bonding wires for electrical signal transmission.

[0009] In one embodiment, a dielectric layer deposited based on an RDL process is provided on the surface of the glass-based RDL layer.

[0010] In one embodiment, the MEMS sensor has one or more combinations of acceleration, gyroscope, temperature and geomagnetic functions.

[0011] In one embodiment, the MEMS is made of diamond, and the ASIC is made of SiC.

[0012] A packaging method for a MEMS sensor based on TGV technology is provided. The method packages the MEMS sensor based on TGV technology described above, comprising: preparing a MEMS and an ASIC using diamond and SiC, respectively, heterogeneously integrating them to obtain a grain layer, and performing surface PAD treatment and gold plating on the grain layer; forming a modified layer on a glass substrate using laser drilling, removing the modified layer using wet etching to form a through hole, and smoothing the inner wall of the through hole using hydrofluoric acid vapor etching; depositing a seed layer based on TGV technology, sputtering titanium as an adhesion layer and copper as a conductive layer, filling the through hole with an acidic copper sulfate electroplating solution, and polishing to remove excess copper on the surface; depositing a dielectric layer by spin coating or spray coating, and performing photolithography and patterning as well as metallization and etching, repeating the dielectric layer deposition, photolithography and patterning, and metallization and etching to obtain a glass-based RDL layer by stacking multiple layers; anodically bonding the grain layer and the glass-based RDL layer to form a chip die, and connecting the chip die to a packaging substrate or lead frame using wire bonding to achieve electrical signal transmission.

[0013] Compared with the prior art, the application has the advantages and beneficial effects that: the crystal grain layer is bonded with the glass-based RDL layer, the crystal grain layer includes the heterogeneously integrated MEMS and ASIC, through the heterogeneously integration of the two, mechanical performance, electrical performance and high-temperature resistance can be considered, the crystal grain layer is subjected to surface PAD treatment and gold plating treatment, and the crystal grain layer is bonded with the anode of the glass-based RDL layer through the surface PAD; the glass-based RDL layer includes a single metalized layer or a multi-layer metalized layer prepared based on the TGV process and the RDL process, glass is used as a dielectric layer between the multi-layer metalized layer, the originally multiple centimeter-sized functional circuits composed of single MEMS or single ASIC, analog signal output circuits and rail-to-rail operational amplifier circuits are all integrated into a micron-sized single-chip die, and then encapsulated to form a chip, so that the originally multiple centimeter-sized circuit board occupies an area of a millimeter-sized single-chip, the amount of discrete components is greatly reduced, the problems of high and low temperature resistance of discrete components, high impedance performance of analog interface and large volume are solved, and the process is simple and easy to implement. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a side sectional view of a MEMS sensor package based on a TGV technology in an embodiment;

[0015] Figure 2 It is a side sectional view of the bonding of the crystal grain layer and the glass-based RDL layer in an embodiment;

[0016] Figure 3 It is a top view schematic diagram of the MEMS and ASIC in an embodiment;

[0017] Figure 4 It is a top view schematic diagram of the top metal layer of the glass-based RDL layer in an embodiment;

[0018] Figure 5 It is a top view schematic diagram of the bottom metal layer of the glass-based RDL layer in an embodiment;

[0019] Figure 6 It is a schematic diagram of a modified layer prepared based on TGV in an embodiment;

[0020] Figure 7 It is a schematic diagram of a via prepared based on TGV in an embodiment;

[0021] Figure 8 It is a schematic diagram of a metalized layer based on TGV in an embodiment;

[0022] Figure 9 It is a schematic diagram of a dielectric layer deposited based on the RDL process in an embodiment;

[0023] Figure 10A flowchart of a packaging method of a MEMS sensor based on TGV technology in an embodiment. DETAILED DESCRIPTION

[0024] In order to make the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work belong to the scope of protection of the present application.

[0025] In an embodiment, as shown in Figures 1-9 a MEMS sensor based on TGV technology is provided, including a bonded die layer 18 and a glass-based RDL layer 19; the die layer 18 includes a heterogeneously integrated MEMS 3 and ASIC 4, the die layer surface is subjected to PAD processing and gold plating processing, the die layer is anodically bonded with the glass-based RDL layer through the surface PAD, and the MEMS and the ASIC are both prepared by using wide-bandgap semiconductor materials; the glass-based RDL layer includes a single-layer metallization layer or a multi-layer metallization layer prepared based on the TGV process and the RDL process, and glass is used as a dielectric layer between the multi-layer metallization layers.

[0026] In the embodiment, the bonded die layer 18 and the glass-based RDL (Redistribution Layer) layer 19 are provided, the die layer 18 includes a heterogeneously integrated MEMS 3 and ASIC 4 (Application-Specific Integrated Circuit), through the heterogenous integration of the two, the mechanical performance, the electrical performance and the high-temperature resistance performance can be considered, the die layer 18 is subjected to surface PAD processing and gold plating processing, and the die layer 18 is anodically bonded with the glass-based RDL layer through the surface PAD; the glass-based RDL layer 19 includes a single-layer metallization layer or a multi-layer metallization layer prepared based on the TGV (Through Glass Via) process and the RDL process, and glass is used as a dielectric layer between the multi-layer metallization layers, the originally multiple centimeter-sized functional circuits composed of single MEMS or single ASIC, analog signal output circuits and rail-to-rail operational amplifier circuits are all integrated into a micron-sized single-chip die, and then packaged to form a chip, so that the originally multiple centimeter-sized circuit board occupation area is reduced to a millimeter-sized single-chip occupation area, the amount of discrete components is greatly reduced, the problems of high-temperature resistance of discrete components, high-impedance performance of analog interfaces and large volume are solved, and the process is simple and easy to implement.

[0027] Specifically, MEMS and ASIC are manufactured on different wafers respectively, and integrated through wafer-level bonding, TGV and other packaging technologies. The process has great freedom and low packaging process difficulty, and MEMS and ASIC can be optimized independently.

[0028] The analog signal output circuit is directly integrated into the ASIC to realize analog signal output. The integrated rail-to-rail operational amplifier circuit provides high impedance for the analog output signal, meeting the high impedance requirements of the analog interface.

[0029] Specifically, pads (PADs) are small metalized areas on a board surface that serve as contact points with component pins or other interconnect elements. Their primary function is to provide stable and reliable connections between PCBs and components such as integrated circuits (ICs), resistors, capacitors, and connectors. Pads enable the transmission of electronic signals and power, ensuring proper functionality.

[0030] Specifically, glass is used as a dielectric layer between the multiple metallization layers. The glass substrate has good high-frequency characteristics and low thermal crosstalk.

[0031] Specifically, the MEMS may be a single MEMS or a collection of multiple MEMS, and the ASIC may be a single ASIC or a collection of multiple ASICs with multiple functions.

[0032] Wherein, multiple PADs are provided on the surface of the MEMS and ASIC for bonding with the glass-based RDL layer, and a gold-plated layer 21 is provided on the surface of the PAD.

[0033] Specifically, in order to achieve electrical connection between multiple devices in the sensor, multiple PADs are provided on the surface of MEMS and ASIC. The bonding between the grain layer and the glass-based RDL layer is achieved through anodic bonding between the surface PAD and the glass-based RDL layer, and a gold-plated layer 21 is provided on the surface of the PAD for bonding the grain layer 19 and the glass-based RDL layer 18 to improve the reliability of welding, prevent oxidation, and improve wear resistance.

[0034] Among them, the glass-based RDL layer 19 includes a top metal layer 1, an intermediate dielectric layer 6 and a bottom metal layer 12; the top metal layer 1 includes a metallized dielectric made based on TGV technology, which is used to electrically connect the PAD2 on the surface of MEMS3 to the PAD5 on the surface of ASIC4 and the packaging substrate 17 or lead frame, and to electrically connect the PAD5 on the surface of ASIC4 to the PAD2 on the surface of MEMS3 and the packaging substrate 8 or lead frame; the intermediate dielectric layer 6 is a glass layer; the bottom metal layer 12 includes a metallized dielectric 15 and PAD made based on TGV technology, which is used to connect to the packaging substrate 17 (or 8) or lead frame through bonding wires 16 (or 7) for electrical signal transmission.

[0035] Specifically, the RDL layer is used to rewire the circuit on the chip to match the external connection point, and the glass-based RDL layer in the application supports more than 12 layers of RDL to realize complex circuit rewiring.

[0036] In the single layer of metallization layer, including the top layer of metal layer 1, the intermediate dielectric layer 6 and the bottom layer of metal layer 12; the top layer of metal layer 1 is made of multiple metallization dielectric based on TGV technology, the PAD 2 on the surface of MEMS 3 is electrically connected with the PAD 5 on the surface of ASIC 4 through the metallization dielectric 13, the PAD 2 on the surface of MEMS 3 is electrically connected with the packaging substrate 17 or the lead frame through the metallization dielectric 14, so as to realize the electrical signal transmission between MEMS 3 and the outside world. Similarly, the PAD 5 on the surface of ASIC 4 is electrically connected with the PAD 2 on the surface of MEMS 3 through the metallization dielectric 11, the PAD 5 on the surface of ASIC 4 is electrically connected with the packaging substrate 8 or the lead frame through the metallization dielectric 10, so as to realize the electrical signal transmission between ASIC 4 and the outside world.

[0037] The intermediate dielectric layer 6 adopts glass layer, which has good high frequency characteristics and small thermal crosstalk.

[0038] The bottom layer of metal layer 12 is provided with metallization dielectric 9 and PAD and metallization dielectric 15 and PAD at both ends based on TGV technology, the metallization dielectric 9 and PAD are connected with the packaging substrate 8 or the lead frame through the bonding wire 7; the metallization dielectric 15 and PAD are connected with the packaging substrate 17 or the lead frame through the bonding wire 16, so as to realize the electrical signal transmission between MEMS 2 and ASIC 3.

[0039] The glass-based RDL layer 18 is made of metallization dielectric line 20 based on TGV technology, which is used to electrically connect the PAD 2 on the surface of MEMS 3 to the surface PAD 5 of ASIC 4.

[0040] The glass-based RDL layer 18 is provided with a dielectric layer 29 deposited on the surface based on RDL process.

[0041] Specifically, the dielectric layer 29 is deposited on the surface of the glass-based RDL layer 18 based on RDL process, and the dielectric layer 29 is used to insulate different conductive layers.

[0042] The glass-based RDL layer 18 is made of modification layer 23 on the glass substrate 22 based on TGV technology, through hole 24 etched in the modification layer, seed layer 25 deposited by metallization, adhesion layer 26 formed by metallization sputtering titanium, conductive layer 27 formed by metallization sputtering copper and electroplated copper filling 28 formed by metallization.

[0043] Among them, the MEMS sensor has one or more of the functions of acceleration, gyroscope, temperature and geomagnetic function.

[0044] Specifically, the MEMS sensor described above can be one or a combination of acceleration, gyroscope, temperature, geomagnetic, etc.

[0045] The MEMS is made of diamond, and the ASIC is made of SiC.

[0046] Specifically, the MEMS and SiC are respectively made of wide-bandgap semiconductor materials diamond and SiC, and the crystal grain layer is heterogeneously integrated, so that mechanical properties, electrical properties and high-temperature resistance can be considered.

[0047] The MEMS and ASIC are respectively made of wide-bandgap semiconductor materials. Among the wide-bandgap semiconductor materials suitable for MEMS, the bandgap of silicon carbide SiC is 3.3eV, the thermal conductivity is 330W / m·K, the bandgap of gallium nitride GaN is 3.4eV, the thermal conductivity is 130W / m·K, the bandgap of diamond is 5.5eV, the thermal conductivity is 2000-2200W / m·K, and the bandgap of aluminum nitride AlN is 6.2eV, the thermal conductivity is 285W / m·K. Considering the mechanical properties and thermal stability of MEMS, diamond becomes the first choice of MEMS material for high mechanical strength and high and low temperature resistance.

[0048] Among the wide-bandgap semiconductor materials suitable for ASIC, the bandgap of SiC is 3.3eV, the thermal conductivity is 330W / m·K, the bandgap of GaN is 3.4eV, the thermal conductivity is 130W / m·K, the bandgap of gallium oxide Ga2O3 is 4.8eV, the thermal conductivity is 27W / m·K, the bandgap of diamond is 5.5eV, the thermal conductivity is 2000-2200W / m·K. Considering the thermal stability and electrical properties of ASIC, SiC (resistant to high temperature up to 600℃) becomes the first choice of high-temperature-resistant ASIC material.

[0049] In one embodiment, as shown in Figure 10 A packaging method of a MEMS sensor based on TGV technology is provided for packaging a MEMS sensor based on TGV technology as described above, comprising the following steps:

[0050] Step S110, the MEMS and ASIC are respectively made of diamond and SiC, the crystal grain layer is heterogeneously integrated, and the surface PAD treatment and gold plating treatment are performed on the crystal grain layer.

[0051] Specifically, both diamond and SiC are wide band gap semiconductor materials, MEMS and ASIC are prepared by using diamond and SiC respectively, silicon on insulator (SOI) with a working temperature of 200 DEG C is used, temperature stable circuit and temperature drift resistant circuit are designed, MEMS and ASIC are prepared and formed, the MEMS and ASIC are heterogeneously integrated to obtain a crystal grain layer, and the crystal grain layer is subjected to surface PAD treatment and gold plating treatment to form a surface PAD and a gold plating layer, so as to facilitate subsequent signal transmission and improve the reliability of welding.

[0052] In step S120, a modification layer is formed on the glass substrate by laser drilling, the modification layer is removed by wet etching to form a through hole, and the inner wall of the through hole is smoothed by hydrofluoric acid gas phase etching.

[0053] Specifically, a modification layer is formed on the glass substrate by laser drilling, the modification layer is removed by wet etching to form a through hole, and the inner wall of the through hole is smoothed by hydrofluoric acid gas phase etching,

[0054] In step S130, a seed layer is deposited based on TGV technology, titanium is sputtered as an adhesion layer, copper is sputtered as a conductive layer, and the through hole is filled by acidic copper sulfate electroplating solution, and the surface excess copper is removed by polishing.

[0055] Specifically, the seed layer is deposited based on TGV technology, titanium is sputtered as an adhesion layer, copper is sputtered as a conductive layer, and the through hole is filled by acidic copper sulfate electroplating solution, and the surface excess copper is removed by polishing.

[0056] In step S140, dielectric layer deposition is performed by spin coating or spraying, and photolithography and patterning and metallization and etching are performed, and dielectric layer deposition, photolithography and patterning and metallization and etching are repeated to obtain a glass substrate RDL layer.

[0057] Specifically, dielectric layer deposition is achieved by spin coating or spraying, photolithography and patterning (photoresist coating, exposure, development), and metallization and etching (sputtering seed layer, copper electroplating, and stripping and etching) to form metal lines. Multi-layer stacking, repeated dielectric layer deposition → photolithography and patterning → metallization and etching, supporting 12 layers or more of RDL.

[0058] In step S150, the crystal grain layer and the glass substrate RDL layer are anodically bonded to form a chip die, the chip die is connected to a packaging substrate or a lead frame by wire bonding to achieve electrical signal transmission.

[0059] Specifically, the crystal grain layer and the glass substrate RDL layer are anodically bonded to form a chip die (die), and finally the chip die is connected to a packaging substrate or a lead frame by wire bonding to achieve electrical signal transmission.

[0060] In the embodiment, the MEMS and the ASIC are prepared by using diamond and SiC respectively, the crystal grain layer is obtained by heterogeneous integration, the crystal grain layer is subjected to surface PAD treatment and gold plating treatment, so that mechanical, electrical and high-temperature-resistant and other performances can be considered; the modified layer is formed on the glass base by laser drilling, the modified layer is removed by wet etching to form a through hole, and the inner wall of the through hole is smoothed by hydrogen fluoride gas phase etching; the seed layer is deposited based on the TGV technology, titanium is sputtered as an adhesion layer, copper is sputtered as a conductive layer, and the through hole is filled by acidic copper sulfate plating solution, and the surface excess copper is removed by polishing; the dielectric layer is deposited by spin coating or spraying, and photoetching and imaging and metallization and etching are carried out, and the dielectric layer deposition, photoetching and imaging and metallization and etching are repeated, and the glass base RDL layer is obtained by multilayer stacking; the crystal grain layer and the glass base RDL layer are anodically bonded to form a chip die, the chip die is connected with the packaging substrate or the lead frame by wire bonding, and the electrical signal transmission is realized, which can greatly reduce the amount of discrete components, avoid the problems of high-temperature resistance, high-impedance performance and large size of discrete components, and the process is simple and easy to implement.

[0061] It should be noted that, in this document, the terms such as first and second are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between such entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device.

[0062] The above is only an embodiment of the present application, and the common knowledge of specific structures and properties in the scheme is not described in detail, and the ordinary skilled person in the art knows all the ordinary technical knowledge in the field of the application before the application date or the priority date, can know all the prior art in the field, and has the ability to apply conventional experimental means before that date, and the ordinary skilled person in the art can improve and implement the present scheme based on the disclosure given in the present application, and some typical known structures or known methods should not be an obstacle for the ordinary skilled person in the art to implement the present application. It should be noted that, for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should also be considered as the protection scope of the present application, which will not affect the effect and practicality of the patent. The protection scope of the present application should be subject to the content of its claims, and the specific embodiments in the specification can be used to explain the content of the claims.

Claims

1. A MEMS sensor based on TGV technology, characterized in that: include: Bonded die layer and glass-based RDL layer; The grain layer includes heterogeneously integrated MEMS and ASIC, the grain layer undergoes surface PAD processing and gold plating processing, the grain layer is anodic bonded to the glass-based RDL layer through the surface PAD, and the MEMS and ASIC are both made of wide bandgap semiconductor materials; The glass-based RDL layer includes a single metallization layer or multiple metallization layers prepared based on the TGV process and the RDL process, and glass is used as a dielectric layer between the multiple metallization layers.

2. The MEMS sensor based on TGV technology according to claim 1, characterized in that: The surfaces of the MEMS and ASIC are both provided with a plurality of PADs for bonding with the glass-based RDL layer, and the surfaces of the PADs are provided with a gold-plated layer.

3. The MEMS sensor based on TGV technology according to claim 1, characterized in that: The glass-based RDL layer includes a top metal layer, an intermediate dielectric layer and a bottom metal layer; The top metal layer includes a metallized medium made based on TGV technology, which is used to electrically connect the PAD on the surface of the MEMS to the PAD on the surface of the ASIC and the packaging substrate or lead frame, and vice versa. The intermediate medium layer is a glass layer; The bottom metal layer includes a metallized medium and a PAD made based on TGV technology, and is used to connect to a packaging substrate or a lead frame through bonding wires for transmitting electrical signals.

4. The MEMS sensor based on TGV technology according to claim 1, characterized in that: A dielectric layer deposited based on an RDL process is provided on the surface of the glass-based RDL layer.

5. The MEMS sensor based on TGV technology according to claim 1, characterized in that: The MEMS sensor has one or more combinations of acceleration, gyroscope, temperature and geomagnetic functions.

6. The MEMS sensor based on TGV technology according to claim 1, characterized in that: The MEMS is made of diamond, and the ASIC is made of SiC.

7. A packaging method for a MEMS sensor based on TGV technology, characterized in that: Used for packaging a MEMS sensor based on TGV technology according to any one of claims 1 to 6, comprising: Diamond and SiC are used to prepare MEMS and ASIC respectively, and a grain layer is obtained by heterogeneous integration, and the surface of the grain layer is subjected to PAD treatment and gold plating treatment; Laser drilling is used to form a modified layer on the glass substrate, wet etching is used to remove the modified layer to form a through hole, and hydrofluoric acid vapor etching is used to smooth the inner wall of the through hole; The seed layer is deposited based on TGV technology, titanium is sputtered as an adhesion layer, copper is sputtered as a conductive layer, and through-holes are filled using an acidic copper sulfate electroplating solution. Excess copper on the surface is polished away. Depositing a dielectric layer by spin coating or spray coating, and performing photolithography and patterning, as well as metallization and etching, repeating the dielectric layer deposition, photolithography and patterning, and metallization and etching, and stacking multiple layers to obtain a glass-based RDL layer; The crystal layer and the glass-based RDL layer are anodically bonded to form a chip bare die, and the chip bare die is connected to a packaging substrate or a lead frame by wire bonding to achieve electrical signal transmission.

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