A MEMS inertial sensor chip module and preparation method thereof

Abstract

The present invention discloses a MEMS inertial sensor chip module and a preparation method thereof. The MEMS inertial sensor chip module of the present invention comprises a housing, wherein the housing is respectively fixed with a PCB board and a metal support column, wherein a MEMS inertial sensor chip assembly is supported on the metal support column, and the connection terminals on the MEMS inertial sensor chip assembly are mutually connected with the connection terminals on the PCB board through metal wires. The present invention does not require a primary packaging process, greatly reduces the packaging and integration costs, reduces the integration volume, avoids the thermal stress involved in surface mounting, can also achieve rapid heat conduction, can maintain various performance indicators of the MEMS inertial sensor chip level, can improve the application restrictions of the prior art on the MEMS inertial sensor chip, and avoids the influence of the primary packaging or secondary packaging thermal stress on the system integration application.

Description

Technical Field

[0001] The present invention relates to semiconductor devices, and in particular to a MEMS inertial sensor chip module and a preparation method thereof, which are used for the integrated assembly of inertial sensor chips such as MEMS gyroscopes and MEMS accelerometers. Background Art

[0002] Inertial sensors based on MEMS technology have the advantages of light weight, low cost, small size, and mass production. They have extremely broad application and development prospects in the civil, aerospace and military fields. Before integration and assembly, MEMS inertial sensor chips are first packaged in the form of ceramic shell packaging, plastic packaging, ceramic substrate COB packaging, etc., and then installed on PCB or other substrates (secondary packaging form) together with passive components using surface mounting technology (SMT), direct chip mounting technology (DCA), through-hole mounting technology (THT) and other technologies to become components or complete machines. The overall process is relatively complicated. Alternatively, low-temperature solder paste is used for surface mounting, but it is not conducive to the subsequent process.

[0003] During the primary and secondary packaging processes, due to the large difference in the coefficient of thermal expansion (CTE) between materials, thermal stress and welding stress are easily caused, and MEMS inertial sensor chips are easily affected by packaging stress and welding stress, especially the full-temperature characteristic indicators; in single-chip integrated packaging, ASIC and MEMS chips are often stacked, and the heat generated by ASIC will also affect the MEMS output performance; in addition, the mold opening or processing costs of ceramic shells, ceramic substrates, plastic shells, etc. are relatively high, and they are not universal, and the volume is significantly increased by several times or even larger relative to the chip. The volume contradiction is particularly obvious in the integrated application of inertial measurement units (IMUs). Summary of the invention

[0004] Technical problem to be solved by the present invention: In view of the above-mentioned problems in the prior art, a MEMS inertial sensor chip module and a preparation method thereof are provided. The present invention does not require a primary packaging process, greatly reduces packaging and integration costs, reduces the integrated volume, avoids thermal stress involved in surface mounting, and can also achieve rapid heat conduction. It can maintain various performance indicators of the MEMS inertial sensor chip level, can improve the application limitations of the prior art on MEMS inertial sensor chips, and avoid the impact of primary or secondary packaging thermal stress on system integration applications.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A MEMS inertial sensor chip module comprises a shell, wherein a PCB board and a metal support column are respectively fixed to the shell, a MEMS inertial sensor chip assembly is supported on the metal support column, and connection terminals on the MEMS inertial sensor chip assembly are mutually connected with connection terminals on the PCB board through metal wires.

[0007] The MEMS inertial sensor chip assembly comprises a MEMS inertial sensor chip and a substrate having a thermal expansion coefficient that is the same as or close to that of the MEMS inertial sensor chip. The MEMS inertial sensor chip is fixed on the substrate, and the substrate support is fixed on the end surface of a metal support column.

[0008] The substrate is also provided with an AISC circuit chip for pre-processing the output of the MEMS inertial sensor chip.

[0009] The PCB board is provided with a via hole, and the metal support column is arranged through the via hole, so that the PCB board and the MEMS inertial sensor chip assembly are arranged parallel to each other.

[0010] The shell includes an upper cover, a main shell and a sealing ring. The upper cover and the main shell are connected by a connecting piece, and the sealing ring is arranged between the end faces of the upper cover and the main shell. The metal support column is glued and fixed to the inner wall of the upper cover or the main shell.

[0011] The metal wire is a gold wire formed by gold wire ball bonding.

[0012] The upper cover and the main shell are made of ceramic or metal.

[0013] The substrate is made of silicon or glass.

[0014] The metal support column is made of tungsten-copper alloy.

[0015] The present invention also provides a method for preparing the aforementioned MEMS inertial sensor chip module, comprising:

[0016] 1) Solder the components of the PCB board and fix them on the main shell;

[0017] 2) Cut out the substrate using a nanosecond laser cutting machine and clean it, deposit a metal conductive layer on the surface of the substrate using a magnetron sputtering method, paste the MEMS inertial sensor chip and the AISC circuit chip on the substrate using conductive silver glue and dry and solidify them to obtain a MEMS inertial sensor chip assembly; paste the MEMS inertial sensor chip assembly on the metal support column and dry and solidify it; pass the metal support column through the via hole on the PCB board and paste it to the inner wall of the main shell using high thermal conductivity silver glue and solidify it at high temperature;

[0018] 3) Connect the connection terminals on the MEMS inertial sensor chip assembly to the connection terminals on the PCB board through gold wire ball welding;

[0019] 4) The main shell is placed in a nitrogen-filled environment, the upper cover and the main shell are connected by a connector, and the sealing ring is arranged between the end faces of the upper cover and the main shell to obtain a shell, and the edge gap of the assembled shell is sealed with a vacuum sealant.

[0020] Compared with the prior art, the MEMS inertial sensor chip module of the present invention has the following advantages:

[0021] 1. The MEMS inertial sensor chip assembly of the present invention can adopt a single-crystal silicon substrate modular single-post MEMS sensor chip or a sealed MEMS sensor chip and an ASIC circuit, without the need for a primary packaging process, which greatly reduces the packaging and integration costs and reduces the integrated volume. It can improve the application restrictions of the prior art on MEMS inertial sensor chips and avoid the impact of primary or secondary packaging thermal stress on system integration applications.

[0022] 2. The shell of the present invention is respectively fixed with a PCB board and a metal support column, and a MEMS inertial sensor chip assembly is supported on the metal support column. The MEMS inertial sensor chip assembly is mounted and fixed to the shell through the metal support column, so that the MEMS inertial sensor chip assembly forms a suspended isolation scheme, and is directly interconnected with the PCB board by gold wire bonding, thereby avoiding the thermal stress involved in surface mounting and realizing rapid heat conduction. In this way, various performance indicators of the MEMS inertial sensor chip level can be maintained.

[0023] 3. The metal support column can play a role in heat conduction, thereby preventing heat accumulation in the MEMS inertial sensor chip assembly, which is beneficial to improving the accuracy of the MEMS inertial sensor chip assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the three-dimensional exploded structure of the MEMS inertial sensor chip module in this embodiment.

[0025] Figure 2 Schematic diagram of the three-dimensional structure of the MEMS inertial sensor chip assembly in this embodiment.

[0026] Figure 3 Schematic diagram of the external structure of the MEMS inertial sensor chip module in this embodiment.

[0027] Figure 4 Schematic diagram of the cross-sectional structure of the MEMS inertial sensor chip assembly in this embodiment.

[0028] Figure 5Schematic diagram of the connection pins of the MEMS inertial sensor chip and the AISC circuit chip in this embodiment.

[0029] Figure 6 This is a 10s smooth curve of the full-temperature zero-bias bias stability of a 15g accelerometer module assembly sample in this embodiment.

[0030] Figure 7 This is a 10s smooth curve of the full-temperature zero-bias bias stability of a non-module assembly sample of a 15g accelerometer in this embodiment.

[0031] Figure 8 This is a temperature compensation curve diagram of a sample temperature box assembled with a 15g accelerometer module in this embodiment.

[0032] Fig. 9 This is a comparison diagram of a 15g accelerometer module #2 before and after temperature compensation during heating and cooling in this embodiment.

[0033] Fig.10 This is a comparison diagram of a 15g accelerometer non-module #2 before and after temperature compensation during heating and cooling in this embodiment.

[0034] Fig.11 This is a data record table of temperature compensation effect of a sample of an accelerometer module assembly in this embodiment.

[0035] Legend: 1. Shell; 11. Upper cover; 12. Main shell; 13. Sealing ring; 2. PCB board; 21. Via hole; 3. Metal support column; 4. MEMS inertial sensor chip assembly; 41. MEMS inertial sensor chip; 42. Substrate; 43. AISC circuit chip. DETAILED DESCRIPTION

[0036] like Figure 1 , Figure 2 and Figure 3 As shown, the MEMS inertial sensor chip module of this embodiment includes a shell 1, to which a PCB board 2 and a metal support column 3 are respectively fixed, and a MEMS inertial sensor chip assembly 4 is supported on the metal support column 3. The connecting terminals on the MEMS inertial sensor chip assembly 4 are interconnected with the connecting terminals on the PCB board 2 through metal wires.

[0037] like Figure 1 , Figure 2 and Figure 4 As shown, in this embodiment, the MEMS inertial sensor chip assembly 4 includes a MEMS inertial sensor chip 41 and a substrate 42 having a thermal expansion coefficient that is the same as or similar to that of the MEMS inertial sensor chip 41 . The MEMS inertial sensor chip 41 is fixed on the substrate 42 , and the substrate 42 is supported and fixed on the end surface of the metal support column 3 .

[0038] It should be noted that the MEMS inertial sensor chip assembly 4 can be a single-crystal silicon substrate modular single-post MEMS sensor chip or a sealed MEMS sensor chip and an ASIC circuit. For example, as an optional implementation, Figure 1 As shown, in this embodiment, the substrate 42 is also provided with an AISC circuit chip 43 for pre-processing the output of the MEMS inertial sensor chip 41. The AISC circuit chip 43 specifically adopts an ACC1904B chip, and the pins are connected as shown in FIG. Figure 5 shown.

[0039] like Figure 1 and Figure 4 As shown, in this embodiment, a via hole 21 is provided on the PCB board 2, and the metal support column 3 is arranged through the via hole 21, so that the PCB board 2 and the MEMS inertial sensor chip assembly 4 are arranged parallel to each other. The metal support column 3 separates the MEMS inertial sensor chip assembly 4 from the PCB board 2 through the PCB board 2 with the via hole 21, and various chips on the MEMS inertial sensor chip assembly 4 are interconnected with the PCB board 2 through metal wires.

[0040] like Figure 4 As shown, in this embodiment, the metal support column 3 is connected to the back side of the AISC circuit chip 43 area on the substrate 42, which is beneficial to improve the heat dissipation effect of the AISC circuit chip 43.

[0041] like Figure 1 , Figure 3 and Figure 4 As shown, in this embodiment, the shell 1 includes an upper cover 11, a main shell 12 and a sealing ring 13. The upper cover 11 and the main shell 12 are connected by a connecting piece, and the sealing ring 13 is arranged between the end surfaces of the upper cover 11 and the main shell 12. The metal support column 3 is glued and fixed on the inner wall of the upper cover 11 or the main shell 12 (in this embodiment, it is specifically glued and fixed on the inner wall of the main shell 12 using high thermal conductivity silver glue).

[0042] In this embodiment, the metal wire is a gold wire formed by gold wire ball bonding, and the specific specification is 1 mil.

[0043] The upper cover 11 and the main shell 12 can be made of ceramic or metal as required, for example, they are made of aluminum alloy in this embodiment.

[0044] The substrate 42 can be made of silicon material or glass material as required, which has the same or similar thermal expansion coefficient as the MEMS inertial sensor chip 41. For example, in this embodiment, the substrate 42 is made of prex7740 glass material.

[0045] In this embodiment, the metal support column 3 is made of tungsten-copper alloy.

[0046] This embodiment also provides a method for preparing the aforementioned MEMS inertial sensor chip module, including:

[0047] 1) Solder the components of the PCB board 2 and fix them on the main housing 12;

[0048] 2) Using a nanosecond laser cutting machine to cut out the substrate 42 and clean it (in this embodiment, it is cleaned using a standard semiconductor wafer cleaning process), using a magnetron sputtering method to deposit a metal conductive layer on the surface of the substrate 42 (to connect the connection terminals of the chip on the substrate to the external circuit and process), using conductive silver glue to paste the MEMS inertial sensor chip 41 and the AISC circuit chip 43 on the substrate 42 and dry and solidify them to obtain a MEMS inertial sensor chip assembly 4; pasting the MEMS inertial sensor chip assembly 4 on the metal support column 3 and drying and solidifying it; passing the metal support column 3 through the via 21 on the PCB board 2 and pasting it to the inner wall of the main shell 12 using high thermal conductivity silver glue and curing it at high temperature;

[0049] 3) The connection terminals on the MEMS inertial sensor chip assembly 4 are connected to the connection terminals on the PCB board 2 by gold wire ball welding; the integrated module is interconnected with the PCB board by direct gold wire bonding, which directly avoids the influence of secondary packaging welding stress, and the overall interconnection process becomes simpler;

[0050] 4) The main shell 12 is placed in a nitrogen-filled environment, the upper cover 11 and the main shell 12 are connected by a connector, and the sealing ring 13 is arranged between the end faces of the upper cover 11 and the main shell 12 to obtain the shell 1, and the edge gap of the assembled shell 1 is sealed with a vacuum sealant.

[0051] When the module is integrated and assembled, the MEMS inertial sensor chip 41 and the AISC circuit chip 43 are pasted to the substrate 42 in a flat manner, and the metal support column 3 is made of tungsten-copper alloy. In this way, the heat generated by the AISC circuit chip 43 can be quickly conducted away, and the heat can also be prevented from directly acting on the MEMS inertial sensor chip 41.

[0052] In this embodiment, a 15g accelerometer is used to implement the whole temperature range performance test of the whole machine. The module is a sample using the MEMS inertial sensor chip module of this embodiment, and the non-module is a sample not using the MEMS inertial sensor chip module of this embodiment. The comparison test is as follows: Figure 6 , Figure 7 , Figure 8 , Fig.10 , Fig.11 As shown. Figure 6 is a 10s smooth curve of the full-temperature zero-bias bias stability of a 15g accelerometer module assembly sample in this embodiment, Figure 7is a 10s smooth curve of the full-temperature zero-bias bias stability of a 15g accelerometer non-module assembly sample in this embodiment, Figure 8 This is a temperature compensation curve of a 15g accelerometer module in this embodiment, Fig. 9 This is a comparison diagram of a 15g accelerometer module #2 before and after temperature compensation. Fig.10 This is a comparison diagram of the temperature compensation before and after the temperature rise and fall of a 15g accelerometer non-module #2 in this embodiment. Fig.11 This is a data record table of the temperature compensation effect of a sample of an accelerometer module assembly in this embodiment. Figure 6 to Figure 11 It can be seen that the 10s smooth data curve of the bias stability in the full temperature range of the samples using the MEMS inertial sensor chip module of this embodiment is smooth, there is no temperature hysteresis phenomenon in the temperature range of -40°C to 60°C, there is no obvious abnormal fluctuation point in the data collection points in the full temperature range, and the repeatability of multiple rounds of tests is good; while the samples that do not use the MEMS inertial sensor chip module of this embodiment, directly use ceramic or metal tube shell packaging, and the secondary packaging is surface-mounted to the PCB, the 10s smooth data curve of the bias stability in the full temperature range has obvious temperature hysteresis effect and zero-position disconnection phenomenon; combined with the temperature compensation temperature curve of the temperature box, the segmented fitting curve is used, and the samples using the MEMS inertial sensor chip module of this embodiment are significantly better than the samples packaged in ceramic or metal tube shells or packaged on ceramic or metal substrates and surface-mounted to PCB boards in terms of temperature compensation effect and overall consistency and stability of the temperature compensation samples.

[0053] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A MEMS inertial sensor chip module, characterized in that: The invention comprises a housing (1), wherein a PCB (2) and a metal support column (3) are respectively fixed to the housing (1), a MEMS inertial sensor chip assembly (4) is supported on the metal support column (3), a connection terminal on the MEMS inertial sensor chip assembly (4) is mutually connected to a connection terminal on the PCB (2) via a metal wire, the MEMS inertial sensor chip assembly (4) comprises a MEMS inertial sensor chip (41) and a substrate (42) having a thermal expansion coefficient that is the same as or similar to that of the MEMS inertial sensor chip (41), the MEMS inertial sensor chip (41) is fixed on the substrate (42), the substrate (42) is supported and fixed on the end surface of the metal support column (3), the PCB (2) is provided with a through hole (21), and the metal support column (3) is arranged to penetrate the through hole (21), so that the PCB (2) and the MEMS inertial sensor chip assembly (4) are arranged parallel to each other.

2. The MEMS inertial sensor chip module according to claim 1, characterized in that: An AISC circuit chip (43) for pre-processing the output of the MEMS inertial sensor chip (41) is also provided on the substrate (42).

3. The MEMS inertial sensor chip module according to claim 2, characterized in that: The housing (1) comprises an upper cover (11), a main shell (12) and a sealing ring (13); the upper cover (11) and the main shell (12) are connected via a connecting piece, and the sealing ring (13) is arranged between the end surfaces of the upper cover (11) and the main shell (12); and the metal support column (3) is glued and fixed to the inner wall of the upper cover (11) or the main shell (12).

4. The MEMS inertial sensor chip module according to claim 3, characterized in that: The metal wire is a gold wire formed by gold wire ball bonding.

5. The MEMS inertial sensor chip module according to claim 4, characterized in that: The upper cover (11) and the main shell (12) are made of ceramic or metal.

6. The MEMS inertial sensor chip module according to claim 5, characterized in that: The substrate (42) is made of silicon or glass.

7. The MEMS inertial sensor chip module according to claim 6, characterized in that: The metal support column (3) is made of tungsten-copper alloy.

8. A method for preparing a MEMS inertial sensor chip module according to any one of claims 3 to 7, characterized in that: include: 1) Soldering the components of the PCB board (2) and fixing them on the main housing (12); 2) using a nanosecond laser cutting machine to cut out a substrate (42) and clean it, using a magnetron sputtering method to deposit a metal conductive layer on the surface of the substrate (42), using a conductive silver glue to adhere a MEMS inertial sensor chip (41) and an AISC circuit chip (43) to the substrate (42), and drying and curing them, to obtain a MEMS inertial sensor chip assembly (4); pasting the MEMS inertial sensor chip assembly (4) to a metal support column (3), and drying and curing them; passing the metal support column (3) through a via hole (21) on a PCB board (2), and pasting it to the inner wall of a main shell (12) using a high thermal conductivity silver glue, and curing it at high temperature; 3) connecting the connection terminals on the MEMS inertial sensor chip assembly (4) to the connection terminals on the PCB board (2) by means of gold wire ball welding; 4) placing the main shell (12) in a nitrogen-filled environment, connecting the upper cover (11) and the main shell (12) via a connector, arranging the sealing ring (13) between the end faces of the upper cover (11) and the main shell (12) to obtain a shell (1), and sealing the edge gap of the assembled shell (1) with a vacuum sealant.

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