Small-size MEMS absolute pressure sensor chip packaging structure and packaging method thereof

Abstract

According to the small-size MEMS absolute pressure sensor chip packaging structure and the packaging method thereof provided by the invention, through preparation of the metal support column and the green oil windowing area, the gap between the MEMS absolute pressure sensor chip and the green oil windowing area can be integrally filled with the bonding dielectric layer, so that the viscous force of the bonding dielectric layer can be greatly improved; according to the MEMS absolute pressure sensor chip, the bonding dielectric layer with enough thickness is arranged below the pressure sensing surface of the MEMS absolute pressure sensor chip, so that the influence of packaging stress or stress in a chip mounting process on the MEMS absolute pressure sensor chip is avoided; a thin bonding dielectric layer is arranged between the MEMS absolute pressure sensor chip and the surface of the PCB substrate, so that the problem of side turning during chip lead bonding can be avoided, and metal wire connection is facilitated; the preparation of the metal support column and the green oil windowing area can be completed without additional process steps, so that the manufacturing cost can be greatly reduced, and the requirements of terminal customers can be better met.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicon micromachined MEMS sensing technology, and relates to a packaging structure and a packaging method for a small-size MEMS absolute pressure sensor chip. Background Art

[0002] Absolute pressure sensors are often used to measure the pressure of fluids such as gases and liquids. When the pressure of the measured medium fluctuates within a certain range, it senses the minute changes in pressure through the deformation of an elastic element and converts them into changes in electrical signals, thereby causing corresponding changes in the output voltage to achieve the measurement of pressure.

[0003] Currently, absolute pressure sensors are widely used in fields such as atmospheric pressure measurement, high-altitude meteorological observation, weather forecasting, medical equipment, aerospace, etc. Among them, as the core component of the absolute pressure sensor, during the packaging process of the MEMS absolute pressure sensor chip, it is necessary to use an adhesive to fix the chip on the substrate and connect the metal pads on the MEMS absolute pressure sensor chip to the substrate through metal wires. During the die bonding process, if the thickness of the adhesive is too large, it will cause the overall height of the MEMS absolute pressure sensor chip to be too high, resulting in relatively difficult metal wire connection and affecting the product yield; if the thickness of the adhesive is too small, the internal stress generated during the curing of the adhesive is large, which will affect the stability of the MEMS absolute pressure sensor chip. If the packaging of the MEMS absolute pressure sensor chip is carried out by increasing the process, the packaging steps will become cumbersome, resulting in the problem of increased manufacturing cost of the absolute pressure sensor.

[0004] Therefore, it is necessary to provide a packaging structure and a packaging method for a small-size MEMS absolute pressure sensor chip. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a packaging structure and a packaging method for a small-size MEMS absolute pressure sensor chip, which are used to solve the product quality and cost problems faced by the packaging of MEMS absolute pressure sensor chips in the prior art.

[0006] To achieve the above purpose and other related purposes, the present invention provides a packaging method for a small-size MEMS absolute pressure sensor chip, including the following steps:

[0007] Provide an insulating board, and form metal support columns on the surface of the insulating board;

[0008] Form a solder mask layer on the surface of the insulating board and the metal support columns to prepare a PCB substrate, wherein the solder mask layer on the insulating board has a solder mask opening area, and the solder mask opening area overlaps with the area surrounded by a plurality of the metal support columns;

[0009] A bonding medium layer is formed within the solder mask opening area;

[0010] A MEMS absolute pressure sensor chip is provided, and the MEMS absolute pressure sensor chip is bonded to the PCB substrate with the pressure-sensing surface facing upward in combination with the metal support posts, and the bonding medium layer integrally fills the gap between the solder mask opening area and the MEMS absolute pressure sensor chip.

[0011] Optionally, the metal support posts are fabricated simultaneously with the metal traces and metal connectors within the PCB substrate.

[0012] Optionally, the solder mask layer is formed by screen printing, and the solder mask opening area is fabricated simultaneously while printing the solder mask layer.

[0013] Optionally, the morphology of the metal support posts includes square, circular or oval; the morphology of the solder mask opening area includes cross-shaped, triangular, circular, oval or cross-star shaped.

[0014] Optionally, the solder mask opening area is centrosymmetric and axisymmetric; the area surrounded by multiple metal support posts is centrosymmetric and axisymmetric; the centers of the solder mask opening area, the area surrounded by multiple metal support posts and the MEMS absolute pressure sensor chip coincide vertically.

[0015] Optionally, the height of the metal support posts is 10μm - 100μm; the thickness of the solder mask layer is 10μm - 50μm; the thickness of the bonding medium layer is 20μm - 100μm; the size of the MEMS absolute pressure sensor chip is below 0.65mm × 0.65mm.

[0016] The present invention further provides a small-size MEMS absolute pressure sensor chip packaging structure, including:

[0017] A PCB substrate, the PCB substrate includes an insulating board, metal support posts and a solder mask layer, wherein the solder mask layer covers the surfaces of the insulating board and the metal support posts, and the solder mask layer located on the insulating board has a solder mask opening area, and the solder mask opening area overlaps with the area surrounded by multiple metal support posts;

[0018] A MEMS absolute pressure sensor chip, the MEMS absolute pressure sensor chip is bonded to the PCB substrate with the pressure-sensing surface facing upward in combination with the metal support posts;

[0019] A bonding medium layer, the bonding medium layer is located between the solder mask opening area and the MEMS absolute pressure sensor chip, and integrally fills the gap between the solder mask opening area and the MEMS absolute pressure sensor chip.

[0020] Optionally, the morphology of the metal support pillars includes square, circular or oval; the morphology of the solder mask opening area includes cross-shaped, triangular, circular, oval or cross-shaped with a small square in the middle.

[0021] Optionally, the solder mask opening area is centrosymmetric and axisymmetric; the area surrounded by multiple metal support pillars is centrosymmetric and axisymmetric; the center of the solder mask opening area, the area surrounded by multiple metal support pillars and the center of the MEMS absolute pressure sensor chip coincide vertically.

[0022] Optionally, the height of the metal support pillars is 10μm - 100μm; the thickness of the solder mask layer is 10μm - 50μm; the thickness of the adhesive medium layer is 20μm - 100μm; the size of the MEMS absolute pressure sensor chip is below 0.65mm × 0.65mm.

[0023] As described above, the small-size MEMS absolute pressure sensor chip packaging structure and its packaging method of the present invention, through the preparation of metal support pillars and solder mask opening areas, enable the gap between the MEMS absolute pressure sensor chip and the solder mask opening area to be integrally filled with an adhesive medium layer, thereby greatly improving the viscosity of the adhesive medium layer; it can make the adhesive medium layer have a sufficient thickness under the pressure-sensing surface of the MEMS absolute pressure sensor chip to avoid the influence of packaging stress or stress during the chip mounting process on the MEMS absolute pressure sensor chip; there is a thin adhesive medium layer between the surface of the MEMS absolute pressure sensor chip and the PCB substrate, which can avoid the problem of side flipping during chip wire bonding and is easy for metal wire connection; without additional process steps, the preparation of metal support pillars and solder mask opening areas can be completed, which can greatly reduce the manufacturing cost and better meet the needs of end customers. Description of the Drawings

[0024] Figure 1 It shows a process flow diagram of the MEMS absolute pressure sensor chip packaging method in an embodiment of the present invention.

[0025] Figure 2 It shows a schematic structural diagram after forming the metal support pillars in an embodiment of the present invention.

[0026] Figure 3 It shows a schematic structural diagram after forming the solder mask opening area in an embodiment of the present invention.

[0027] Figure 4 It shows a schematic structural diagram after forming the adhesive medium layer in an embodiment of the present invention.

[0028] Figure 5 It shows a schematic structural diagram after forming the structure with the MEMS absolute pressure sensor chip attached in an embodiment of the present invention.

[0029] Description of Reference Numerals

[0030] 100 Metal Support Columns

[0031] 201 Green oil layer on the surface of metal support column

[0032] 202 Green oil layer on insulation board

[0033] 300 Green Oil Window Area

[0034] 400 Adhesive medium layer

[0035] 500 MEMS absolute pressure sensor chip DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present invention through 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.

[0037] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional view showing the device structure will not be partially enlarged according to the general scale, and the schematic view is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional space dimensions of length, width and depth should be included.

[0038] For ease of description, spatial relational terms such as “under”, “below”, “below”, “below”, “over”, etc. may be used herein to describe the relationship of one element or feature shown in the drawings to other elements or features. It will be understood that these spatial relational terms are intended to include other orientations of the device in use or operation in addition to the orientation depicted in the drawings, and may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, so that the first and second features may not be in direct contact. In addition, when a layer is referred to as being “between” two layers, it may be the only layer between the two layers, or one or more intervening layers may also be present.

[0039] It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and therefore the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0040] like Figure 1, this embodiment provides a packaging method for a small-size MEMS absolute pressure sensor chip, including the following steps:

[0041] S1: Provide an insulating board, and form metal support columns on the surface of the insulating board;

[0042] S2: Form a solder mask layer on the surfaces of the insulating board and the metal support columns to prepare a PCB substrate. Among them, the solder mask layer on the insulating board has a solder mask opening area, and the solder mask opening area overlaps with the area surrounded by a plurality of the metal support columns;

[0043] S3: Form an adhesive medium layer in the solder mask opening area;

[0044] S4: Provide a MEMS absolute pressure sensor chip, and bond the MEMS absolute pressure sensor chip with the metal support columns with the pressure-sensing surface facing up on the PCB substrate, and the adhesive medium layer integrally fills the gap between the solder mask opening area and the MEMS absolute pressure sensor chip.

[0045] In this embodiment, through the preparation of the metal support columns and the solder mask opening area, the gap between the MEMS absolute pressure sensor chip and the solder mask opening area can be integrally filled with the adhesive medium layer, thereby greatly improving the viscosity of the adhesive medium layer; it can make the adhesive medium layer with sufficient thickness under the pressure-sensing surface of the MEMS absolute pressure sensor chip to avoid the influence of packaging stress or stress during the chip mounting process on the MEMS absolute pressure sensor chip; there is a thin adhesive medium layer between the surface of the MEMS absolute pressure sensor chip and the PCB substrate, which can avoid the problem of side turning during chip wire bonding and is easy for metal wire connection; without additional process steps, the preparation of the metal support columns and the solder mask opening area can be completed, which can greatly reduce the manufacturing cost and better meet the needs of end customers.

[0046] The following combines the description Figures 2 to 5 , and introduces the packaging method of the MEMS absolute pressure sensor chip.

[0047] First, refer to Figure 2 , execute step S1, provide an insulating board (not shown), and form metal support columns 100 on the surface of the insulating board.

[0048] As an example, it is preferred that the metal support columns 100 are prepared simultaneously with the metal traces (not shown) and metal connectors (not shown) in the PCB substrate, so that the metal support columns 100 can be prepared without additional process steps.

[0049] Specifically, the metal connectors may include, for example, pads, metal fingers, etc. The materials of the metal support posts 100, the metal traces, and the metal connectors may include, for example, copper material, but are not limited thereto. The material and type of the insulating board are not overly restricted herein.

[0050] Among them, for the preparation of the metal support posts 100, the following steps may be included:

[0051] Provide the insulating board;

[0052] Drill holes in the insulating board (not shown);

[0053] Form a metal seed layer (not shown) on the insulating board, such as a copper metal seed layer, etc.;

[0054] Form a patterned mask (not shown) on the metal seed layer, such as photoresist, etc.;

[0055] By electrochemical method, deposit metal ions in the electrolyte on the metal seed layer and remove the mask;

[0056] By etching, remove the excess metal seed layer, thereby preparing the metal support posts while forming the metal traces and the metal connectors.

[0057] As an example, the morphology of the metal support posts 100 may include square, circular, oval, etc.

[0058] Specifically, the morphology of the metal support posts 100 can be set as needed, such as by controlling the patterning of the above mask to prepare the metal support posts 100 with the required morphology.

[0059] As an example, the number of the metal support posts 100 may include N≥3, such as N being 3, 4, 5, 6, 8, etc.

[0060] Specifically, the main function of the metal support posts 100 is to support the subsequently attached MEMS absolute pressure sensor chip 500. Among them, referring to Figures 2 to 5 , in this embodiment, it is preferably provided with 4 metal support posts 100 to support the 4 corners of the MEMS absolute pressure sensor chip 500, but the number of the metal support posts 100 is not limited thereto. For example, to further improve stability, 5, 6, 8, etc. can also be set.

[0061] Next, referring to Figure 3, perform step S2 to form a solder mask layer on the surfaces of the insulating board and the metal support posts 100, namely, the solder mask layer 201 on the surface of the metal support posts 100 and the solder mask layer 202 on the surface of the insulating board, to prepare a PCB substrate. Among them, the solder mask layer 202 on the insulating board has a solder mask opening area 300, and the solder mask opening area 300 intersects with the area surrounded by the plurality of metal support posts 100.

[0062] As an example, the solder mask layer can be formed by screen printing, and preferably, the solder mask opening area 300 is prepared while printing the solder mask layer, so that the solder mask opening area 300 can be prepared without additionally increasing the process steps.

[0063] Specifically, the formation of the solder mask opening area 300 can provide a accommodation space for the subsequent formation of the bonding medium layer 400. Thus, through the limiting effect of the solder mask opening area 300, the viscosity of the bonding medium layer 400 can be improved.

[0064] As an example, the morphology of the solder mask opening area 300 can include a cross shape, a triangle, a circle, an ellipse, a star shape, etc.

[0065] Specifically, the morphology of the solder mask opening area 300 is related to the morphology of the area surrounded by the plurality of metal support posts 100, so that after the MEMS absolute pressure sensor chip 500 is attached subsequently, the bonding medium layer 400 can be located directly below the structural sensitive area, i.e., the pressure sensing area, of the MEMS absolute pressure sensor chip 500, facilitating the stable attachment of the MEMS absolute pressure sensor chip 500. For example, Figures 3 to 5 , in this embodiment, the morphology of the solder mask opening area 300 is a cross shape, but it is not limited thereto.

[0066] Next, refer to Figure 4 , perform step S3 to form a bonding medium layer 400 in the solder mask opening area 300.

[0067] Specifically, the type of the bonding medium layer 400 can include, for example, die bonding soft glue, and the bonding medium layer 400 can include an insulating bonding material or a bonding material with good heat dissipation filled with metal ions, etc. The specific type is not limited here.

[0068] Among them, the method for forming the bonding medium layer 400 can include dispensing, painting, screen printing, etc., and is not overly restricted here.

[0069] Next, refer to Figure 5, perform step S4, provide the MEMS absolute pressure sensor chip 500, and attach the MEMS absolute pressure sensor chip 500 to the PCB substrate with the pressure-sensitive surface facing up in combination with the metal support posts 100, and the adhesive medium layer 400 integrally fills the gap between the solder mask opening area 300 and the MEMS absolute pressure sensor chip 500.

[0070] As an example, the size of the MEMS absolute pressure sensor chip 500 is 0.65 mm × 0.65 mm or less, such as 0.65 mm × 0.65 mm, 0.5 mm × 0.5 mm, 0.5 mm × 0.6 mm, 0.2 mm × 0.4 mm, etc. Among them, the morphology of the MEMS absolute pressure sensor chip 500 may include, for example, a rectangle or a square.

[0071] Specifically, during the process of attaching the MEMS absolute pressure sensor chip 500, when the size of the MEMS absolute pressure sensor chip 500 is smaller, the problems of chip tipping and stress are more obvious. The packaging method of this embodiment is applicable to the small-sized MEMS absolute pressure sensor chip 500, which can effectively solve the problems of chip tipping and stress and achieve good attachment.

[0072] As an example, preferably, the solder mask opening area 300 is centrosymmetric and an axisymmetric figure; the area surrounded by the plurality of metal support posts 100 is centrosymmetric and an axisymmetric figure; the centers of the solder mask opening area 300, the area surrounded by the plurality of metal support posts 100, and the MEMS absolute pressure sensor chip 500 coincide vertically.

[0073] Specifically, when the solder mask opening area 300 is centrosymmetric and an axisymmetric figure, the area surrounded by the plurality of metal support posts 100 is centrosymmetric and an axisymmetric figure, and the centers of the solder mask opening area 300, the area surrounded by the plurality of metal support posts 100, and the MEMS absolute pressure sensor chip 500 coincide vertically, it is convenient for the stable attachment of the MEMS absolute pressure sensor chip 500 and improves the reliability of the device.

[0074] As an example, the height of the metal support post 100 can be 10 μm to 100 μm, such as 10 μm, 20 μm, 30 μm, 50 μm, 80 μm, and 100 μm, etc.; the thickness of the solder mask layer can be 10 μm to 50 μm, such as 10 μm, 15 μm, 20 μm, 30 μm, 50 μm, etc.; the thickness of the adhesive medium layer 400 can be 20 μm to 100 μm, such as 20 μm, 35 μm, 40 μm, 45 μm, 50 μm, 80 μm, 100 μm, etc.

[0075] Specifically, in this embodiment, due to the presence of the metal support posts 100 and the solder mask opening area 300, the adhesive dielectric layer 400 can be partially filled in the solder mask opening area 300. Thus, after bonding the MEMS absolute pressure sensor chip 500, there will be a relatively thin adhesive dielectric layer 400 between the bottom surface of the MEMS absolute pressure sensor chip 500 and the surface of the PCB substrate, i.e., the surface of the solder mask layer 202. This can avoid the problem of tipping during chip wire bonding, making it easy for wire connection. At the same time, it can ensure that there is a sufficiently thick adhesive dielectric layer 400 between the bottom surface of the MEMS absolute pressure sensor chip 500 and the insulating plate, thereby avoiding the influence of packaging stress or stress during chip mounting on the MEMS absolute pressure sensor chip.

[0076] Referring to Figures 2 to 5 , this embodiment also provides a small-size MEMS absolute pressure sensor chip packaging structure. Among them, the MEMS absolute pressure sensor chip packaging structure can be prepared by the above preparation process, but is not limited to the above method. In this embodiment, the MEMS absolute pressure sensor chip packaging structure is directly prepared by the above preparation method, so the preparation, materials, etc. of the MEMS absolute pressure sensor chip packaging structure will not be elaborated here.

[0077] Among them, the MEMS absolute pressure sensor chip packaging structure includes:

[0078] A PCB substrate, which includes an insulating plate, metal support posts 100, and a solder mask layer. Among them, the solder mask layer covers the surfaces of the insulating plate and the metal support posts 100, that is, the solder mask layer includes a solder mask layer 201 on the surface of the metal support posts 100 and a solder mask layer 202 on the surface of the insulating plate. And the solder mask layer 202 on the insulating plate has a solder mask opening area 300, and the solder mask opening area 300 intersects with the area surrounded by the plurality of metal support posts 100;

[0079] A MEMS absolute pressure sensor chip 500, which is bonded to the metal support posts 100 and is attached to the PCB substrate with the pressure-sensing surface facing up;

[0080] An adhesive dielectric layer 400, which is located between the solder mask opening area 300 and the MEMS absolute pressure sensor chip 500, and integrally fills the gap between the solder mask opening area 300 and the MEMS absolute pressure sensor chip 500.

[0081] As an example, the morphology of the metal support posts 100 can include square, circular, oval, etc.; the morphology of the solder mask opening area 300 can include cross-shaped, triangular, circular, oval, or star-shaped, etc.

[0082] As an example, it is preferred that the solder mask opening area 300 is a centrosymmetric and axially symmetric figure; the area surrounded by the plurality of metal support columns 100 is a centrosymmetric and axially symmetric figure; the centers of the solder mask opening area 300, the area surrounded by the plurality of metal support columns 100, and the MEMS absolute pressure sensor chip 500 coincide vertically.

[0083] Specifically, when the solder mask opening area 300 is a centrosymmetric and axially symmetric figure, the area surrounded by the plurality of metal support columns 100 is a centrosymmetric and axially symmetric figure, and the centers of the solder mask opening area 300, the area surrounded by the plurality of metal support columns 100, and the MEMS absolute pressure sensor chip 500 coincide vertically, it is convenient for the stable attachment of the MEMS absolute pressure sensor chip 500, and the reliability of the device is improved.

[0084] As an example, the size of the MEMS absolute pressure sensor chip 500 is 0.65 mm × 0.65 mm or less, such as 0.65 mm × 0.65 mm, 0.5 mm × 0.5 mm, 0.5 mm × 0.6 mm, 0.2 mm × 0.4 mm, etc. Among them, the morphology of the MEMS absolute pressure sensor chip 500 may include, for example, a rectangle or a square.

[0085] Specifically, during the attachment process of the MEMS absolute pressure sensor chip 500, when the size of the MEMS absolute pressure sensor chip 500 is smaller, the problems of chip tipping and stress are more obvious. The packaging structure of this embodiment is applicable to the small-sized MEMS absolute pressure sensor chip 500, and can effectively solve the problems of chip tipping and stress, and achieve good attachment.

[0086] As an example, the height of the metal support column 100 can be 10 μm to 100 μm, such as 10 μm, 20 μm, 30 μm, 50 μm, 80 μm, and 100 μm, etc.; the thickness of the solder mask layer can be 10 μm to 50 μm, such as 10 μm, 15 μm, 20 μm, 30 μm, 50 μm, etc.; the thickness of the adhesive medium layer 400 can be 20 μm to 100 μm, such as 20 μm, 35 μm, 40 μm, 45 μm, 50 μm, 80 μm, 100 μm, etc.

[0087] Specifically, in this embodiment, due to the presence of the metal support posts 100 and the solder mask opening area 300, the adhesive medium layer 400 can be partially filled in the solder mask opening area 300. Thus, after the MEMS absolute pressure sensor chip 500 is attached, there is a relatively thin adhesive medium layer 400 between the bottom surface of the MEMS absolute pressure sensor chip 500 and the surface of the PCB substrate, i.e., the surface of the solder mask layer 202. This can avoid the problem of tipping during chip wire bonding, facilitating metal wire connection. At the same time, it can ensure that there is a sufficiently thick adhesive medium layer 400 between the bottom surface of the MEMS absolute pressure sensor chip 500 and the insulating plate, thereby avoiding the influence of packaging stress or stress during the chip mounting process on the MEMS absolute pressure sensor chip.

[0088] In summary, for the small-size MEMS absolute pressure sensor chip packaging structure and its packaging method of the present invention, through the preparation of the metal support posts and the solder mask opening area, the gap between the MEMS absolute pressure sensor chip and the solder mask opening area can be integrally filled with the adhesive medium layer, thereby greatly improving the viscosity of the adhesive medium layer; it can ensure that there is a sufficiently thick adhesive medium layer under the pressure-sensitive surface of the MEMS absolute pressure sensor chip to avoid the influence of packaging stress or stress during the chip mounting process on the MEMS absolute pressure sensor chip; there is a relatively thin adhesive medium layer between the MEMS absolute pressure sensor chip and the surface of the PCB substrate, which can avoid the problem of tipping during chip wire bonding and facilitate metal wire connection; without additional process steps, the preparation of the metal support posts and the solder mask opening area can be completed, greatly reducing the manufacturing cost and better meeting the needs of end customers.

[0089] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A small-size MEMS absolute pressure sensor chip packaging method, characterized in that: The following steps are involved: Providing an insulating plate, and forming a metal support column on the surface of the insulating plate; Forming a green oil layer on the surface of the insulating plate and the metal support column to prepare a PCB substrate, wherein the green oil layer on the insulating plate has a green oil window area, and the green oil window area overlaps with an area surrounded by a plurality of the metal support columns; forming an adhesive medium layer in the green oil window area; A MEMS absolute pressure sensor chip is provided, and the MEMS absolute pressure sensor chip is attached to the PCB substrate with the pressure-sensitive surface facing upward in combination with the metal support column, and the adhesive medium layer is integrally filled with the gap between the green oil window area and the MEMS absolute pressure sensor chip.

2. The MEMS absolute pressure sensor chip packaging method according to claim 1, characterized in that: The metal support column is prepared simultaneously with the metal wiring and metal connectors in the PCB substrate.

3. The MEMS absolute pressure sensor chip packaging method according to claim 1, characterized in that: The green oil layer is formed by screen printing, and the green oil window area is prepared while printing the green oil layer.

4. The MEMS absolute pressure sensor chip packaging method according to claim 1, characterized in that: The shape of the metal support column includes square, circle or ellipse; the shape of the green oil window area includes cross, triangle, circle, ellipse or cross.

5. The MEMS absolute pressure sensor chip packaging method according to claim 1, characterized in that: The green oil window area is centrally symmetrical and axially symmetrical; the area surrounded by the multiple metal support columns is centrally symmetrical and axially symmetrical; the center of the green oil window area, the area surrounded by the multiple metal support columns and the center of the MEMS absolute pressure sensor chip overlap vertically.

6. The MEMS absolute pressure sensor chip packaging method according to claim 1, characterized in that: The height of the metal support column is 10 μm to 100 μm; the thickness of the green oil layer is 10 μm to 50 μm; the thickness of the adhesive medium layer is 20 μm to 100 μm; and the size of the MEMS absolute pressure sensor chip is less than 0.65 mm×0.65 mm.

7. A small-size MEMS absolute pressure sensor chip packaging structure, characterized in that: include: A PCB substrate, the PCB substrate comprising an insulating plate, a metal support column and a green oil layer, wherein the green oil layer covers the surfaces of the insulating plate and the metal support column, and the green oil layer located on the insulating plate has a green oil window area, and the green oil window area overlaps with an area surrounded by a plurality of the metal support columns; A MEMS absolute pressure sensor chip, wherein the MEMS absolute pressure sensor chip is combined with the metal support column and attached to the PCB substrate with the pressure-sensitive surface facing upward; An adhesive medium layer is located between the green oil window area and the MEMS absolute pressure sensor chip, and integrally fills the gap between the green oil window area and the MEMS absolute pressure sensor chip.

8. The MEMS absolute pressure sensor chip packaging structure according to claim 7, characterized in that: The shape of the metal support column includes square, circle or ellipse; the shape of the green oil window area includes cross, triangle, circle, ellipse or cross.

9. The MEMS absolute pressure sensor chip packaging structure according to claim 7, characterized in that: The green oil window area is centrally symmetrical and axially symmetrical; the area surrounded by the multiple metal support columns is centrally symmetrical and axially symmetrical; the center of the green oil window area, the area surrounded by the multiple metal support columns and the center of the MEMS absolute pressure sensor chip overlap vertically.

10. The MEMS absolute pressure sensor chip packaging structure according to claim 7, characterized in that: The height of the metal support column is 10 μm to 100 μm; the thickness of the green oil layer is 10 μm to 50 μm; the thickness of the adhesive medium layer is 20 μm to 100 μm; and the size of the MEMS absolute pressure sensor chip is less than 0.65 mm×0.65 mm.

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