Packaging structure of micro high-temperature pressure sensor

Abstract

The application belongs to the field of pressure sensor manufacturing, and particularly relates to a packaging structure of a micro high-temperature pressure sensor. Metal is filled into lead hole on a glass cover, first through hole and connecting groove on a ceramic fixing sheet by using a vapor deposition method, and then the metal in the lead hole on the pressure-sensitive chip and the metal in the first through hole on the ceramic fixing sheet are welded together by using ultrasonic welding to provide high-strength connection while leading out the electrical signal of the pressure-sensitive chip. A plurality of second through holes with the same number as the first through holes and with diameters larger than the first through holes are arranged on the ceramic fixing sheet, the first through holes and the second through holes are connected through the connecting grooves, and the metal in the first through holes and the wire penetrating through the second through holes are connected through the metal filled in the connecting grooves to provide a site for welding of the wire with a relatively large diameter. The packaging structure of the micro high-temperature pressure sensor greatly improves the strength of the connection and the reliability of the sensor in use.

Description

Technical Field

[0001] This application relates to the field of pressure sensor manufacturing technology, and in particular to a packaging structure for a miniature high-temperature pressure sensor. Background Technology

[0002] For pressure sensor piezoresistive chips with a diameter of 2mm × 2mm or less, current technologies connect metal leads to chip pads via high-temperature sintering of silver paste. However, the sintering temperature reaches 550℃, exceeding the temperature of the preceding anodic bonding process, which can easily lead to bonding interface failure. Secondly, the size of the leads connecting to the chip pads is affected by the chip size. When the chip size is reduced to 2mm × 2mm, the diameter of the leads connecting to the pads is also less than 0.2mm. This reduction in lead size significantly increases the difficulty of lead extraction, and the leads themselves are not very strong. Furthermore, the leads and chip pads are generally connected using silver paste sintering. Due to the limited glass aperture size of the piezoresistive chip, the amount of silver paste filling is insufficient, making it impossible to achieve a high-strength connection. In addition, for subsequent sensor use, the leads need to be connected to thicker wires. However, the welding method used for wire connections is difficult to apply due to the thin leads, resulting in low weld strength and reducing the reliability of the sensor. Summary of the Invention

[0003] This application provides a packaging structure for a miniature high-temperature pressure sensor, which aims to improve the connection strength and reliability between the metal leads and the pressure-sensitive chip.

[0004] To achieve the above objectives, this application provides a packaging structure for a miniature high-temperature pressure sensor, comprising:

[0005] A pressure-sensitive chip includes a diaphragm and a glass cover bonded to the diaphragm. The glass cover has multiple lead holes, and each lead hole is filled with metal by vapor deposition.

[0006] A ceramic fixing plate has a first side and a second side arranged opposite to each other. The first side has a positioning groove in the middle that is adapted to the pressure-sensitive chip. The bottom of the positioning groove has a plurality of first through holes that correspond one-to-one with each of the lead holes on the glass cover. The ceramic fixing plate has a plurality of second through holes surrounding the positioning groove, the same number as the first through holes. The diameter of the second through holes is larger than the diameter of the first through holes. The second side has a plurality of connecting grooves. The plurality of first through holes and the plurality of second through holes are connected one-to-one through the plurality of connecting grooves. Each first through hole and each connecting groove is filled with metal by vapor deposition. The pressure-sensitive chip is placed in the positioning groove, and the metal filled in each of the lead holes on the glass cover is welded one-to-one with the metal filled in each of the first through holes by ultrasonic welding.

[0007] Multiple wires are inserted one-to-one into multiple second through holes from the second side and welded to the metal filling the connecting groove.

[0008] A ceramic base is provided with a mounting groove for accommodating the ceramic fixing plate. The bottom of the mounting groove has multiple clearance channels for each of the wires to pass through. The ceramic fixing plate is embedded in the mounting groove, and the multiple wires pass through the multiple clearance channels one by one and extend outwards.

[0009] The outer shell includes a cylindrical body and an end cap. The cylindrical body is sleeved on the outside of the ceramic base. The end cap covers the end of the ceramic base that has the mounting groove and is connected to the cylindrical body. The end cap has a pressure guiding hole.

[0010] Optionally, a metal sleeve is provided in the second through hole, and the metal sleeve is connected to the metal filled in the connecting groove. One end of the wire passes through the second through hole from the second side and is welded to the metal sleeve on the first side.

[0011] Optionally, the metal sleeve and the second through hole are transition-fitted.

[0012] Optionally, the lead hole tapers from the end furthest from the diaphragm to the end closest to the diaphragm.

[0013] Optionally, high-temperature sealant is applied to the weld joint between the wire and the ceramic fixing plate, and between the ceramic fixing plate and the wall of the mounting groove.

[0014] Optionally, the end cap is detachably connected to the cylinder.

[0015] Optionally, the outer wall of the cylinder has a coarse diameter section and a fine diameter section connected to each other. The fine diameter section is located at the end of the outer wall of the cylinder near the ceramic base where the mounting groove is provided. The end cap is connected to the fine diameter section by a thread. The outer diameter of the end cap is less than or equal to the outer diameter of the coarse diameter section. The coarse diameter section is provided with an external thread for external connection.

[0016] Optionally, the cylinder is made of metal.

[0017] The beneficial effects of the packaging structure of the miniature high-temperature pressure sensor provided in this application are as follows: Compared with the prior art, the packaging structure of the miniature high-temperature pressure sensor in this application utilizes vapor deposition to fill metal into the lead holes on the glass cover of the pressure-sensitive chip and the first through holes and connecting grooves on the ceramic fixing plate. Then, ultrasonic welding is used to weld the metal in the lead holes on the pressure-sensitive chip to the metal in the first through holes on the ceramic fixing plate. This provides a high-strength connection while leading out the electrical signal of the pressure-sensitive chip, avoiding the low connection strength caused by using excessively thin leads. The ceramic fixing plate is provided with multiple second through holes, the same number as the first through holes and with a larger diameter. The first through holes and the second through holes are connected by connecting grooves. The metal filled in the connecting grooves connects the metal in the first through holes and the wires passing through the second through holes, thereby dispersing the "clustered" electrical signal paths and providing space for welding thicker diameter wires. This packaging structure of the miniature high-temperature pressure sensor greatly improves the connection strength and enhances the reliability of the sensor. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] in:

[0020] Figure 1 This is a schematic diagram of the overall packaging structure of a miniature high-temperature pressure sensor according to an embodiment of this application;

[0021] Figure 2 yes Figure 1 The diagram shows the structure of the miniature high-temperature pressure sensor after removing the end cap.

[0022] Figure 3 This is a cross-sectional view of the packaging structure of a miniature high-temperature pressure sensor according to an embodiment of this application;

[0023] Figure 4 This is a schematic diagram of the pressure-sensitive chip in the packaging structure of a miniature high-temperature pressure sensor according to an embodiment of this application;

[0024] Figure 5 This is a cross-sectional view of the pressure-sensitive chip in the packaging structure of a miniature high-temperature pressure sensor according to an embodiment of this application;

[0025] Figure 6This is a schematic diagram of the first and second sides of the ceramic fixing plate in the packaging structure of a miniature high-temperature pressure sensor according to an embodiment of this application;

[0026] Figure 7 This is a top view of the ceramic base and the cylinder after they are connected in the packaging structure of a miniature high-temperature pressure sensor according to an embodiment of this application;

[0027] Figure 8 This is a cross-sectional view of the ceramic base and the cylinder after they are connected in the packaging structure of a miniature high-temperature pressure sensor according to an embodiment of this application.

[0028] Explanation of key component symbols:

[0029] 100. Pressure-sensitive chip; 110. Diaphragm; 120. Glass cover; 121. Lead hole;

[0030] 200. Ceramic fixing plate; 2001. First side; 2002. Second side; 201. Positioning groove; 202. First through hole; 203. Second through hole; 2031. Metal sleeve; 204. Connecting groove;

[0031] 300. Wire;

[0032] 400. Ceramic base; 401. Mounting groove; 402. Clearance passage;

[0033] 500, outer shell; 510, cylinder; 511, external thread; 520, end cap; 521, pressure guide hole. Detailed Implementation

[0034] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many other different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0035] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0036] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0039] It should also be noted that in the embodiments of this application, the same reference numerals are used to represent the same component or part. For the same part in the embodiments of this application, the reference numerals may only be used to mark one part or component as an example. It should be understood that the reference numerals are also applicable to other identical parts or components.

[0040] Embodiments of this application provide a packaging structure for a miniature high-temperature pressure sensor, such as... Figures 1-3 As shown, the packaging structure of this miniature high-temperature pressure sensor includes a pressure-sensitive chip 100, a ceramic fixing plate 200, multiple wires 300, a ceramic base 400, and a housing 500.

[0041] Combination Figures 4-5 As shown, the pressure-sensitive chip 100 includes a diaphragm 110 and a glass cover 120 bonded to the diaphragm 110. The glass cover 120 has multiple lead holes 121, each filled with metal using a vapor deposition method to lead an electrode to the outside of the glass cover 120. Figure 6As shown, the ceramic fixing plate 200 has a first side 2001 and a second side 2002 arranged opposite to each other. The middle part of the first side 2001 is provided with a positioning groove 201 adapted to the pressure-sensitive chip 100. The bottom of the positioning groove 201 is provided with a plurality of first through holes 202 corresponding one-to-one with each lead hole 121 on the glass cover 120. The ceramic fixing plate 200 is provided with a plurality of second through holes 203 around the positioning groove 201, the same number as the number of first through holes 202. The diameter of the second through holes 203 is larger than that of the first through holes 202. The diameter of the hole 202 is specified. The second side 2002 has multiple connecting grooves 204. Multiple first through holes 202 and multiple second through holes 203 are connected one-to-one via the connecting grooves 204. Each first through hole 202 and each connecting groove 204 is filled with metal using vapor deposition. The pressure-sensitive chip 100 is placed in the positioning groove 201, and the metal filling each lead hole 121 on the glass cover 120 is ultrasonically welded to the metal filling each first through hole 202. Multiple wires 300 pass through the second side 2002 one-to-one into the multiple second through holes 203 and are welded to the metal filling the connecting grooves 204. Figure 7 and Figure 8 As shown, the ceramic base 400 is provided with a mounting groove 401 for accommodating the ceramic fixing plate 200. The bottom of the mounting groove 401 is provided with multiple clearance channels 402 for each wire 300 to pass through. The ceramic fixing plate 200 is embedded in the mounting groove 401, and the multiple wires 300 pass through the multiple clearance channels 402 one by one and are led outward. The outer shell 500 includes a cylindrical body 510 and an end cap 520. The cylindrical body 510 is sleeved on the outside of the ceramic base 400, and the end cap 520 covers the end of the ceramic base 400 with the mounting groove 401 and is connected to the cylindrical body 510. The end cap 520 is used to protect the diaphragm 110 in the pressure-sensitive chip 100, and the end cap 520 is provided with a pressure guiding hole 521.

[0042] In this embodiment, the packaging structure of the miniature high-temperature pressure sensor utilizes vapor deposition to fill metal into the lead hole 121 on the glass cover 120 of the pressure-sensitive chip 100 and the first through hole 202 and connecting groove 204 on the ceramic fixing plate 200. Then, ultrasonic welding is used to weld the metal in the lead hole 121 of the pressure-sensitive chip 100 to the metal in the first through hole 202 of the ceramic fixing plate 200. This provides a high-strength connection while simultaneously leading out the electrical signal from the pressure-sensitive chip 100, avoiding the low connection strength caused by using excessively thin leads. The mounting plate 200 has multiple second through holes 203, the same number as the first through holes 202 but with a larger diameter. The first through holes 202 and the second through holes 203 are connected by a connecting groove 204. Metal filled in the connecting groove 204 connects the metal in the first through holes 202 to the wires 300 passing through the second through holes 203. The purpose is to disperse the clustered and smaller diameter first through holes 202 outwards, thereby dispersing the "clustered" electrical signal paths and providing space for welding the larger diameter wires 300. The packaging structure of this miniature high-temperature pressure sensor greatly improves the connection strength and enhances the reliability of the sensor.

[0043] Among them, conductor 300 can be made of high temperature conductor. High temperature conductor is a type of conductor with excellent corrosion resistance, resistance to oil, strong acid, strong alkali, strong oxidant, etc.; excellent electrical insulation performance, high voltage resistance, low high frequency loss, non-hygroscopic, high insulation resistance; excellent flame resistance, aging resistance, and long service life.

[0044] In one embodiment, such as Figures 2-3 and Figure 6 As shown, a metal sleeve 2031 is provided in the second through hole 203. The metal sleeve 2031 is connected to the metal filled in the connecting groove 204, so that the electrical signal generated by the pressure-sensitive chip 100 can reach the metal sleeve 2031 through the metal filled in the lead hole 121, the metal filled in the first through hole 202, and the metal filled in the connecting groove 204. One end of the wire 300 passes through the second through hole 203 from the second side 2002 and is soldered to the metal sleeve 2031 on the first side 2001.

[0045] By using the metal sleeve 2031 that is tightly fixed inside the second through hole 203, the wire 300 can be welded to it over a large area. Because the welded part is large, the welding strength can be improved, and the unreliability caused by welding the wire 300 to the thin lead wire can be avoided.

[0046] Specifically, the metal sleeve 2031 and the second through hole 203 are in a transition fit. Of course, it is conceivable that the metal sleeve 2031 and the second through hole 203 can also be in an interference fit or bonded together.

[0047] In one embodiment, such as Figure 5 As shown, the lead hole 121 tapers from the end furthest from the diaphragm 110 to the end closest to the diaphragm 110. This design makes the lead hole 121 a tapered hole, which facilitates the deposition of metal into the lead hole 121 by vapor deposition.

[0048] In one embodiment, a high-temperature sealant is applied to the weld joint between the wire 300 and the ceramic fixing plate 200, and between the ceramic fixing plate 200 and the wall of the mounting groove 401. This sealant serves to fix the pressure-sensitive core (the integral formed by ultrasonic welding of the pressure-sensitive chip 100 and the ceramic fixing plate 200) and protect the weld joint.

[0049] In one embodiment, the end cap 520 is detachably connected to the cylinder 510, which facilitates cleaning of the diaphragm 110 surface of the pressure-sensitive chip 100 after the miniature high-temperature pressure sensor has been used for a period of time.

[0050] Understandably, the detachable connection between the end cap 520 and the cylinder 510 can be made in ways including but not limited to threaded connections and snap-fit ​​connections.

[0051] In one embodiment, such as Figures 1-3 As shown, the outer wall of the cylinder 510 has a coarse diameter section and a fine diameter section connected to each other. The fine diameter section is located at the end of the outer wall of the cylinder 510 near the ceramic base 400 where the mounting groove 401 is provided. The end cap 520 is connected to the fine diameter section by a thread, which facilitates assembly and disassembly. The outer diameter of the end cap 520 is less than or equal to the outer diameter of the coarse diameter section. The coarse diameter section is provided with an external thread 511 for external connection.

[0052] This design allows the miniature high-temperature pressure sensor to be externally mounted and fixed via the external thread 511 on the outer diameter section of the outer wall of the cylinder 510 during use. The outer diameter of the end cap 520 is designed to be less than or equal to the outer diameter of the outer diameter section, thus preventing the end cap 520 from being too large and affecting the connection between the external thread 511 on the cylinder 510 and the threaded hole on the external structure.

[0053] Specifically, the cylinder 510 is made of metal, which is sturdy and durable, and at the same time provides good protection for the ceramic base 400 located inside it.

[0054] In summary, combining Figures 1-8 As shown, the packaging structure of the miniature high-temperature pressure sensor provided in this application is adopted, and the specific packaging process is as follows:

[0055] First, a metal layer is filled into the five lead holes 121 on the glass cover 120 of the pressure-sensitive chip 100 using vapor deposition. Simultaneously, a special structure is metallized on the ceramic fixing plate 200 using vapor deposition. This special structure includes a first through hole 202 at the bottom of the positioning groove 201 and a connecting groove 204 on the second side 2002. A second through hole 203 surrounds the positioning groove 201 (i.e., near the edge of the ceramic fixing plate 200), and a metal sleeve 2031 is fitted within the second through hole 203. The pressure-sensitive chip 100 is placed in the positioning groove 201 according to the positional correspondence between the lead holes 121 and the first through holes 202. Then, ultrasonic welding equipment is used to weld the ceramic fixing plate 200 to the metal layer on the glass cover 120 of the pressure-sensitive chip 100 to form a pressure-sensitive core, thereby enabling the transmission of electrical signals and the fixation between the pressure-sensitive chip 100 and the ceramic fixing plate 200. The wire 300 passes through the metal sleeve 2031 from the second side 2002 of the ceramic fixing plate 200, and is welded to the metal sleeve 2031 on the first side 2001 to achieve a high-strength connection of the wire 300. The ceramic base 400 has a clearance channel 402 corresponding to the position of the metal sleeve 2031 on the ceramic fixing plate 200, and a mounting groove 401 of the same size as the ceramic fixing plate 200 is provided at the top of the ceramic base 400. The fabricated pressure-sensitive core is placed into the mounting groove 401 on the ceramic base 400, and the welded wire 300 is simultaneously passed through the clearance channel 402 on the ceramic base 400. A layer of high-temperature sealant is applied between the welded joint of the wire 300 and the ceramic fixing plate 200, and between the ceramic fixing plate 200 and the groove wall of the mounting groove 401, to fix the pressure-sensitive core and protect the welded joint. Two threads are provided on the outer wall of the cylindrical body 510 of the outer shell 500. The large thread (i.e. the external thread 511 on the coarse diameter section of the cylindrical body 510 in the above embodiment) plays the role of fixing the micro high temperature pressure sensor in the use of the micro high temperature pressure sensor. The small thread is threaded to the end cap 520 with four pressure guiding holes 521, which can protect the diaphragm 110 of the pressure-sensitive chip 100.

[0056] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A packaging structure for a miniature high-temperature pressure sensor, characterized in that, include: A pressure-sensitive chip includes a diaphragm and a glass cover bonded to the diaphragm. The glass cover has multiple lead holes, and each lead hole is filled with metal by vapor deposition. A ceramic fixing plate has a first side and a second side arranged opposite to each other. The first side has a positioning groove in the middle that is adapted to the pressure-sensitive chip. The bottom of the positioning groove has a plurality of first through holes that correspond one-to-one with each of the lead holes on the glass cover. The ceramic fixing plate has a plurality of second through holes surrounding the positioning groove, the same number as the first through holes. The diameter of the second through holes is larger than the diameter of the first through holes. The second side has a plurality of connecting grooves. The plurality of first through holes and the plurality of second through holes are connected one-to-one through the plurality of connecting grooves. Each first through hole and each connecting groove is filled with metal by vapor deposition. The pressure-sensitive chip is placed in the positioning groove, and the metal filled in each of the lead holes on the glass cover is welded one-to-one with the metal filled in each of the first through holes by ultrasonic welding. Multiple wires are inserted one-to-one into multiple second through holes from the second side and welded to the metal filling the connecting groove. A ceramic base is provided with a mounting groove for accommodating the ceramic fixing plate. The bottom of the mounting groove has multiple clearance channels for each of the wires to pass through. The ceramic fixing plate is embedded in the mounting groove, and the multiple wires pass through the multiple clearance channels one by one and extend outwards. The outer shell includes a cylindrical body and an end cap. The cylindrical body is sleeved on the outside of the ceramic base. The end cap covers the end of the ceramic base that has the mounting groove and is connected to the cylindrical body. The end cap has a pressure guiding hole. A metal sleeve is provided in the second through hole, and the metal sleeve is connected to the metal filling the connecting groove. One end of the wire passes through the second through hole from the second side and is welded to the metal sleeve on the first side. The lead hole tapers from the end furthest from the diaphragm to the end closest to the diaphragm; High-temperature sealant is applied to the weld joint between the wire and the ceramic fixing plate, and between the ceramic fixing plate and the wall of the mounting groove.

2. The packaging structure of the miniature high-temperature pressure sensor according to claim 1, characterized in that, The metal sleeve is fitted with the second through hole.

3. The packaging structure of the miniature high-temperature pressure sensor according to claim 1, characterized in that, The end cap is detachably connected to the cylinder.

4. The packaging structure of the miniature high-temperature pressure sensor according to claim 1, characterized in that, The outer wall of the cylinder has a coarse diameter section and a fine diameter section connected to each other. The fine diameter section is located at the end of the outer wall of the cylinder near the ceramic base where the mounting groove is provided. The end cap is connected to the fine diameter section by a thread. The outer diameter of the end cap is less than or equal to the outer diameter of the coarse diameter section. The coarse diameter section is provided with an external thread for external connection.

5. The packaging structure of the miniature high-temperature pressure sensor according to claim 1, characterized in that, The cylinder is made of metal.

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