Absolute pressure sensor packaging structure

Abstract

This application discloses an absolute pressure sensor packaging structure, belonging to the field of micro-electromechanical systems. The structure comprises a package base, an adhesive material, an adapter, and an absolute pressure sensor chip. The adapter replaces the conventional package base opening method used in previous packaging methods, allowing ambient pressure to be introduced from the front, without opening the pressure sensor package base. This effectively achieves stress isolation and electrical isolation of the sensor chip, thereby achieving superior output performance and improving the stability of the pressure sensor product. Furthermore, the use of a low-stress adhesive material reduces the stress effects caused by the packaging material while achieving high pressure bearing capacity, effectively reducing sensor signal offset.

Description

Technical Field

[0001] The present application relates to the field of absolute pressure sensor packaging, and in particular to an absolute pressure sensor packaging structure. Background Art

[0002] Pressure sensors have a wide range of applications in the semiconductor field, for example, to measure and control atmospheric pressure and liquid pressure. As their application areas continue to expand, they can be widely used in automotive, medical, industrial equipment, consumer electronics and other fields.

[0003] In micro-electro-mechanical system (MEMS) packaging technology, bonding is currently the primary method used to achieve hermetic packaging. Commonly used hermetic packaging processes include anodic bonding, eutectic bonding, and fusion bonding in a high vacuum environment (less than 0.01 Pa).

[0004] Absolute pressure sensor chips contain a vacuum reference cavity. The pressure being measured is sensed by the pressure difference between the pressure-sensitive membrane and the reference cavity. In some harsh operating environments, the packaging structure is required to protect the internal chip while ensuring electrical signal transmission. Furthermore, sensor signal drift is a key metric for high-end pressure sensors. This drift is often directly caused by factors such as the chip substrate material, the chip manufacturing process, and the chip packaging material. The choice of adhesive during chip packaging is particularly critical. While physically securing the chip, minimizing the impact of adhesive stress on chip performance is a key research focus. Summary of the Invention

[0005] The present application provides an absolute pressure sensor packaging structure that can optimize the sensor output signal drift and repeatability problems caused by bonding materials during the packaging process.

[0006] The embodiment of the present application provides an absolute pressure sensor package structure, comprising: a package base 101, a bonding material 102, a transfer piece 103 and an absolute pressure sensor chip 104;

[0007] One side of the adapter 103 is mounted on the package base 101 through the adhesive material 102 , and the other side of the adapter 103 is connected to the absolute pressure sensor chip 104 through the adhesive material 102 ;

[0008] The bonding material 102 is a low-stress material.

[0009] Optionally, the absolute pressure sensor chip 104 is packaged in the packaging cavity of the package body;

[0010] Pressure sensitive areas and chip electrodes are provided on different surfaces of the absolute pressure sensor chip 104 , and the pressure sensitive areas and the chip electrodes are exposed in the packaging cavity.

[0011] The package base 101 is provided with a connection electrode, which is used to achieve signal conduction;

[0012] In the absolute pressure sensor package structure, the chip electrode 105 is electrically connected to the connection electrode provided on the package base 101 through the metal connection wire 108, so as to transmit the internal signal of the absolute pressure sensor package structure to the outside.

[0013] Optionally, a vertical opening and a horizontal opening are formed on the adapter 103 , and the vertical opening and the horizontal opening are used to introduce ambient pressure from the front.

[0014] Optionally, a slot is provided at the bottom of the absolute pressure sensor chip 104 , and the slot is used to introduce ambient pressure from the front.

[0015] Optionally, the chip electrode is arranged outside the pressure sensitive area.

[0016] Optionally, the absolute pressure sensor package structure includes at least one absolute pressure sensor chip 104 , and the absolute pressure sensor chips 104 are electrically connected to each other through the metal connection wires 108 .

[0017] Optionally, the absolute pressure sensor package structure further includes a conditioning circuit chip, and the conditioning circuit chip is disposed in the absolute pressure sensor package structure;

[0018] The conditioning circuit chip is electrically connected to the absolute pressure sensor chip 104 via the metal connection wire 108 .

[0019] Optionally, the conditioning circuit chip is further electrically connected to the connection electrode via the metal connection wire 108 and the conductive connection member.

[0020] Optionally, the connecting electrode is arranged on an outer layer of the package body.

[0021] The technical solution of this application has at least the following advantages:

[0022] To address the issues of signal drift and repeatability caused by adhesive materials during the packaging process, this application proposes an absolute pressure sensor packaging structure. This structure includes a package base, adhesive material, an adapter, and an absolute pressure sensor chip. The adapter replaces the conventional package base opening method used in previous packaging processes, allowing ambient pressure to be introduced from the front. This effectively achieves stress isolation and electrical isolation of the sensor chip without opening the package base, thereby achieving superior output performance and improving the stability of the absolute pressure sensor product. Furthermore, the use of a low-stress adhesive material reduces the stress effects of the packaging material while achieving high pressure bearing capacity, effectively reducing sensor signal offset. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 A schematic structural diagram of an absolute pressure sensor packaging structure provided by an embodiment of the present invention is shown;

[0025] Figure 2 A schematic structural diagram of another absolute pressure sensor packaging structure provided by an embodiment of the present invention is shown;

[0026] Figure 3 The figure shows a connection diagram of a conditioning circuit chip provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in this application in conjunction with the accompanying drawings. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0028] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal connections between two components; they can refer to wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0030] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0031] First, let's introduce the background of the absolute pressure sensor chip involved in this application. An absolute pressure sensor is a transducer that converts pressure signals into electrical signals. Absolute pressure sensors use a vacuum as a reference. The sensor encapsulates a vacuum cavity, and the vacuum within the cavity serves as the reference. Traditional packaging structures can reduce the sensor's accuracy and durability.

[0032] High-end MEMS pressure sensors often use a metal base or ceramic housing as the package base. When the electrode and sensitive membrane of a MEMS absolute pressure sensor chip are not on the same side, a hole is often required at the bottom of the package base. This hole allows electrical conduction from the back of the chip to the pressure-sensitive membrane to sense pressure changes. In this case, the glue used to bond the chip requires high bond strength to prevent the pressure chip, which is under pressure from the back, from falling off the package base under high pressure. However, high bond strength often results in high external stress, which can reduce the performance of the pressure sensor.

[0033] To address the aforementioned packaging issues, the present invention provides an absolute pressure sensor packaging structure that achieves high pressure bearing capacity while reducing the stress caused by the packaging material, effectively reducing sensor signal offset, and thus improving the performance of the absolute pressure sensor. This absolute pressure sensor packaging structure is gradually disclosed in the following specification. Example 1

[0034] Please refer to Figure 1 , which shows a schematic diagram of an absolute pressure sensor packaging structure provided by an illustrative embodiment of the present application, the structure includes a packaging base 101, an adhesive material 102, a adapter 103 and an absolute pressure sensor chip 104.

[0035] In order to integrate MEMS devices with other devices, it is often necessary to integrate MEMS devices with CMOS devices and then package the integrated devices. In the prior art, the chip integrating MEMS devices and CMOS devices is first packaged separately, which is a complex packaging method with high cost and low efficiency.

[0036] The packaging involved in the embodiment of the present invention mainly has low requirements on the strength of the bonding material. A low-stress bonding material 102 is selected to improve product performance, withstand high pressure, increase the degree of chip miniaturization, reduce the impact of internal stress transmitted in all directions of the packaging material, effectively reduce the sensor signal offset, and improve the reliability of the absolute pressure sensor structure.

[0037] The package is Figure 1 The overall structure of the package body is mainly composed of a package base 101, a bonding material 102, a adapter 103 and an absolute pressure sensor chip 104 arranged in the package body.

[0038] Furthermore, one side of the adapter 103 is mounted on the package base 101 via the adhesive material 102 , and the other side of the adapter 103 is connected to the absolute pressure sensor chip 104 via the adhesive material 102 .

[0039] Optionally, the adapter 103 and the absolute pressure sensor chip 104 may be directly connected through wafer-level bonding.

[0040] Furthermore, unlike conventional packaging structures that directly open holes in the package base, the package structure of the present invention does not have holes in the package base. Instead, vertical and horizontal holes are formed on the adapter 103. These vertical and horizontal holes are used to introduce ambient pressure from the front. The shape and number of the holes can be flexibly adjusted according to the actual scenario.

[0041] In another possible implementation, the following solution can achieve the same effect as the method of forming vertical openings and horizontal openings: A slot is formed at the bottom of the absolute pressure sensor chip 104, and the slot is also used to introduce ambient pressure from the front.

[0042] To address the issues of signal drift and repeatability caused by adhesive materials during the packaging process, this application proposes an absolute pressure sensor packaging structure. This structure includes a package base, adhesive material, an adapter, and an absolute pressure sensor chip. The adapter replaces the conventional package base opening method used in previous packaging processes, allowing ambient pressure to be introduced from the front. This eliminates the need for an opening in the absolute pressure sensor package base, effectively achieving stress isolation and electrical isolation of the sensor chip. This allows the absolute pressure sensor to achieve superior output performance and enhance the stability of the absolute pressure sensor product. Furthermore, the use of a low-stress adhesive material reduces the stress effects of the packaging material while achieving high pressure bearing capacity, effectively reducing sensor signal offset. Example 2

[0043] Further, such as Figure 2 As shown, the absolute pressure sensor chip 104 is packaged in the packaging cavity of the package body, and pressure sensitive areas 106 and chip electrodes 105 are provided on different surfaces of the absolute pressure sensor chip 104 .

[0044] The pressure sensitive area 106 and each chip electrode 105 are exposed in the packaging cavity. The pressure sensitive area 106 is Figure 2 At the thin film 106 shown in the figure, the chip electrode 105 is arranged on the periphery of the pressure sensitive area 106.

[0045] Furthermore, connection electrodes are provided in the package base 101 , and the connection electrodes are used to achieve signal conduction.

[0046] In the absolute pressure sensor package structure, the chip electrode 105 is electrically connected to the connection electrode provided on the package base 101 through the metal connection wire 108, which is used to transmit the internal signal of the absolute pressure sensor package structure to the outside. Among them, the connection electrode is provided on the outer layer of the package body.

[0047] Optionally, the absolute pressure sensor package structure includes at least one absolute pressure sensor chip 104 , and the absolute pressure sensor chips 104 are electrically connected to each other through the metal connection wires 108 .

[0048] Furthermore, the absolute pressure sensor packaging structure also includes a conditioning circuit chip 107 .

[0049] The conditioning circuit chip 107 is disposed in the absolute pressure sensor package structure, and the conditioning circuit chip 107 is electrically connected to the absolute pressure sensor chip 104 via a metal connection line 108 .

[0050] Optionally, the conditioning circuit chip 107 is also electrically connected to the connection electrode through the metal connection wire 108 and the conductive connection member.

[0051] In one possible implementation, Figure 3 As shown, chip electrodes 105 are wire-bonded to conditioning circuit chip 107 mounted on package base 101 or electrodes on package base 101. If connected to conditioning circuit chip 107, the conditioning circuit chip is then wire-bonded to electrodes on package base 101. The electrodes on the top of package base 101 are then electrically connected to electrodes on the back of package base 101, enabling signal transmission. Simultaneously, the back electrodes are soldered to a peripheral circuit board for application.

[0052] Optionally, the conditioning circuit chip 107 may be placed side by side with the absolute pressure sensor chip 104 as shown in the figure, or may be stacked, that is, placed overlapping with the absolute pressure sensor chip 104 above and below.

[0053] In the embodiment of the present invention, the contents of the pressure sensitive area, chip electrodes, connecting electrodes, electrical connection structure and conditioning circuit chip are further disclosed, and the realization of signal transmission and circuit board application is explained.

[0054] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of this application.

Claims

1. An absolute pressure sensor packaging structure, characterized in that: include: A packaging base (101), a bonding material (102), a transfer component (103), and an absolute pressure sensor chip (104); One side of the adapter (103) is mounted on the package base (101) via the adhesive material (102), and the other side of the adapter (103) is connected to the absolute pressure sensor chip (104) via the adhesive material (102); the adhesive material (102) is a low-stress material; Alternatively, the adapter (103) and the absolute pressure sensor chip (104) are directly connected via wafer-level bonding; A vertical opening and a horizontal opening are formed on the adapter (103), and the vertical opening and the horizontal opening are used to introduce ambient pressure from the front; A slot is provided at the bottom of the absolute pressure sensor chip (104), and the slot is used to introduce ambient pressure from the front; The absolute pressure sensor chip (104) is packaged in a packaging cavity of a packaging body; Different surfaces of the absolute pressure sensor chip (104) are provided with pressure sensitive areas (106) and chip electrodes (105), and the pressure sensitive areas (106) and the chip electrodes (105) are exposed in the packaging cavity.

2. The absolute pressure sensor packaging structure according to claim 1, characterized in that: A connecting electrode is provided in the packaging base (101), and the connecting electrode is used to achieve signal conduction; In the absolute pressure sensor packaging structure, a chip electrode (105) is electrically connected to a connection electrode provided on the packaging base (101) via a metal connection wire (108), so as to transmit an internal signal of the absolute pressure sensor packaging structure to the outside.

3. The absolute pressure sensor packaging structure according to claim 1, characterized in that: The chip electrode is arranged on the periphery of the pressure sensitive area.

4. The absolute pressure sensor packaging structure according to claim 2, wherein: The absolute pressure sensor packaging structure comprises at least one absolute pressure sensor chip (104), and the absolute pressure sensor chips (104) are electrically connected to each other via the metal connection wires (108).

5. The absolute pressure sensor packaging structure according to claim 2, wherein: The absolute pressure sensor packaging structure further comprises a conditioning circuit chip (107), and the conditioning circuit chip (107) is arranged in the absolute pressure sensor packaging structure; The conditioning circuit chip (107) and the absolute pressure sensor chip (104) are electrically connected via the metal connection wire (108).

6. The absolute pressure sensor packaging structure according to claim 5, characterized in that: The conditioning circuit chip (107) is also electrically connected to the connection electrode via the metal connection wire (108) and the conductive connection member.

7. The absolute pressure sensor packaging structure according to claim 2, characterized in that: The connecting electrode is arranged on the outer layer of the package body.

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