A leadless package pressure sensor and a packaging method thereof

Abstract

The application provides a leadless packaging pressure sensor and a packaging method thereof, the pressure sensor comprising: a sintering tube shell, a cover body matched with the sintering tube shell to form a containing cavity, and a pressure sensor chip arranged in the containing cavity, lead posts are arranged in the sintering tube shell, the pressure sensor chip is provided with lead holes matched with the lead posts, the lead holes are filled with conductive paste, and the lead posts and the pressure sensor chip are conducted. In the above manner, the leadless packaging pressure sensor can be packaged quickly while ensuring stable sensor performance, the internal structure after packaging is convenient to check, the overall performance of the pressure sensor is ensured, and the yield is improved.

Description

Technical Field

[0001] This invention relates to the field of pressure sensor technology, and specifically to a leadless packaged pressure sensor and its packaging method. Background Technology

[0002] Pressure sensors are becoming increasingly miniaturized, which poses a growing challenge to pressure sensor packaging technology. The current structure of high-temperature leadless pressure sensors on the market has the problem of being inconvenient for leadless pressure sensor packaging. After the pressure chip is mounted, it is impossible to inspect the morphology and other defects of the sealing sintered glass paste around the chip, which also greatly reduces the yield of pressure sensors.

[0003] To reduce the packaging difficulty of electrical and sealing connections between the pressure chip and the glass sintered housing in a leadless pressure sensor, and to facilitate inspection after chip mounting, a leadless packaged pressure sensor is provided to address current shortcomings. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned deficiencies of the prior art by providing a leadless packaged pressure sensor.

[0005] The objective of this invention can be achieved through the following technical measures:

[0006] To achieve the above objectives, the present invention provides a leadless packaged pressure sensor, the pressure sensor comprising a sintered housing, a cover that mates with the sintered housing to form a receiving cavity, and a pressure sensor chip disposed within the receiving cavity.

[0007] The cover includes an end cap and a first sidewall extending perpendicularly to the end cap along the edge of the end cap.

[0008] The sintered tube shell includes an end face, a second sidewall extending perpendicular to the end face along the edge of the end face, an insulating layer disposed on the end face, and a lead post penetrating the end face and the insulating layer and extending along the direction of the second sidewall.

[0009] The pressure sensor chip has lead holes that correspond one-to-one with the lead posts. The lead posts mate with the lead holes, and conductive paste is filled between the lead holes and the lead posts. The pressure sensor chip abuts against the insulating layer.

[0010] Preferably, the sintered tube shell further includes a bottom surface extending from the end of the second sidewall away from the end face along a path close to the end of the lead post, the bottom surface being annular; and a third sidewall extending from the edge of the bottom surface away from the second sidewall toward the end face, the third sidewall surrounding the lead post and parallel to the second sidewall.

[0011] Preferably, the sintered tube shell further includes a boss extending from the second sidewall toward the direction away from the lead post, and the side of the first sidewall away from the end cap abuts against the boss.

[0012] Preferably, the boss extends circumferentially along the second sidewall.

[0013] Preferably, the distance from the boss to the end face is less than the length of the first sidewall extending from the end cap.

[0014] Preferably, the pressure sensor chip includes a glass layer, a metal layer, and a silicon layer stacked sequentially on the insulating layer, and the lead hole is located in the glass layer.

[0015] Preferably, the lead hole is tapered.

[0016] Preferably, the end cap is provided with several through holes.

[0017] This application also provides a method for packaging a leadless pressure sensor, the method comprising:

[0018] The sealing slurry is screen-printed onto the surface of the insulation layer of the sintered tube shell;

[0019] The conductive paste is filled into the lead holes of the pressure sensor chip;

[0020] The filled pressure sensor chip is attached to the printed insulating layer using a pick-and-place machine, and the lead post is inserted into the lead hole.

[0021] The pressure sensor chip is sintered and sealed onto the sintered tube shell;

[0022] Check whether the pressure sensor chip and the sintered tube shell are fully fitted after sintering.

[0023] Preferably, before sintering and sealing the pressure sensor chip onto the sintered housing, the process further includes checking whether the pressure sensor chip and the lead post are fully fitted.

[0024] The beneficial effects of this invention are that it provides a leadless packaged pressure sensor and its packaging method. The pressure sensor includes: a sintered shell, a cover that mates with the sintered shell to form a cavity, and a pressure sensor chip disposed within the cavity. The cover includes an end cap and a first sidewall extending perpendicularly to the end cap along its edge. The sintered shell includes an end face, a second sidewall extending perpendicularly to the end face along its edge, an insulating layer disposed on the end face, and lead posts penetrating the end face and the insulating layer and extending along the direction of the second sidewall. The pressure sensor chip has lead holes corresponding one-to-one with the lead posts. The lead posts mate with the lead holes, and conductive paste is filled between the lead holes and the lead posts. The pressure sensor chip abuts against the insulating layer. Through this method, the leadless packaged pressure sensor can achieve stable sensor performance while being quick to package, facilitating inspection of the internal structure after packaging, thus ensuring the overall performance of the pressure sensor and improving the yield rate. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the leadless packaged pressure sensor according to an embodiment of the present invention.

[0026] Figure 2 This is an exploded structural diagram of the leadless packaged pressure sensor according to an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of the mating structure of the pressure sensor and the sintered tube shell according to an embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram of the leadless packaged pressure sensor according to an embodiment of the present invention along the AA section.

[0029] Figure Description: Leadless packaged pressure sensor 100; sintered housing 1; end face 11; second sidewall 12; insulating layer 13; lead post 14; boss 16; bottom face 17; third sidewall 18; cover 2; end cap 21; first sidewall 22; through hole 23; pressure sensor chip 3; lead hole 31; glass layer 32; metal layer 33; silicon layer 34. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] To make the description of this disclosure more detailed and complete, illustrative descriptions of embodiments and specific examples of the present invention are provided below; however, these are not the only forms of implementing or utilizing the specific examples of the present invention. The embodiments cover features of multiple specific examples and methods and steps for constructing and operating these specific examples, and their order. However, other specific examples may also be used to achieve the same or equivalent functions and order of steps.

[0032] This invention provides a leadless packaged pressure sensor 100. Please refer to [link / reference]. Figures 1-4 The pressure sensor 100 includes a sintered tube shell 1, a cover 2 that cooperates with the sintered tube shell 1 to form a receiving cavity, and a pressure sensor chip 3 disposed in the receiving cavity.

[0033] The cover 2 includes an end cap 21 and a first side wall 22 extending along the edge of the end cap 21 perpendicular to the end cap 21. The end cap 21 is provided with a plurality of through holes 23, which can transfer the temperature of the outside to the accommodating cavity.

[0034] The sintered tube shell 1 includes an end face 11, a second sidewall 12 extending along the edge of the end face 11 perpendicular to the end face 11, an insulating layer 13 disposed on the end face 12, and a lead post 14 penetrating the end face 11 and the insulating layer 13 and extending along the extending direction of the second sidewall 12. The end face 11 and the insulating layer are both flat planes, which are circular planes in this case, but can also be other shapes.

[0035] The pressure sensor chip 3 has lead holes 21 corresponding to the lead posts 14 one-to-one. The lead holes 21 are tapered, and the lead posts 14 mate with the lead holes 21. A conductive paste 15 (not shown) is filled between the lead holes 21 and the lead posts 14. The pressure sensor chip 3 abuts against the insulating layer 13. There are four lead posts 14, corresponding to four lead holes 21, and the conductive paste 15 allows for electrical conductivity between the pressure sensor chip 3 and the lead posts 14.

[0036] The leadless packaged pressure sensor 100 of this application embodiment can achieve stable sensor performance while being quick to package, facilitating the inspection of the internal structure after packaging, which is beneficial to ensuring the overall performance of the pressure sensor and improving the yield.

[0037] Based on the above embodiments, in an optional implementation, the sintered shell 1 further includes a bottom surface 17 extending from the end of the second sidewall 12 away from the end face 11 along the end near the lead post 14, the bottom surface 17 being annular; and a third sidewall 18 extending from the edge of the bottom surface 17 away from the second sidewall 12 toward the end face 11, the third sidewall 18 surrounding the lead post 14 and parallel to the second sidewall 12. The third sidewall 18 can provide a function of concentrating and protecting the lead post 14.

[0038] Based on the above embodiments, in an optional implementation, the sintered tube shell 1 further includes a boss 16 extending from the second sidewall 12 in a direction away from the lead post 14. The boss 16 extends circumferentially along the second sidewall 12, and the side of the first sidewall 22 away from the end cap 21 abuts against the boss 16. The distance from the boss 16 to the end face 11 is less than the length of the first sidewall 22 extending from the end cap 21.

[0039] Based on the above embodiments, in an optional implementation, the pressure sensor chip 3 includes a glass layer 32, a metal layer 33, and a silicon layer 34 stacked sequentially on an insulating layer 13, with a lead hole 31 located in the glass layer 32. Since the pressure sensor chip 3 is ultimately fixed to the insulating layer 13 of the sintered housing during the packaging process, the insulating layer 13 is preferably made of the material that contacts the pressure sensor chip 3; therefore, the insulating layer 32 is preferably made of glass. The lead hole 31 is tapered and penetrates the glass layer. By filling the lead hole 31 with conductive paste 15 (not shown), and then cooperating with the lead post 14, the conductive paste 15 can connect to the metal layer 33 and the lead post 14 respectively, thereby conducting electricity between the metal layer 33 and the lead post 14, and transmitting the electrical signal of pressure change of the pressure sensor chip 3 along the lead post. The silicon layer 34 is sensitive to external temperature changes and can deform at high temperatures. The metal layer 33 can receive the deformation of the silicon layer 34 and convert the deformation into an electrical signal.

[0040] Based on the leadless packaged pressure sensor 100 of the above embodiments, this application also provides a packaging method for the leadless packaged pressure sensor 100, including:

[0041] Step S1: The sealing slurry is screen-printed onto the surface of the insulating layer of the sintered tube shell;

[0042] Step S2: Fill the lead hole of the pressure sensor chip with conductive paste;

[0043] Step S3: The filled pressure sensor chip is attached to the printed insulating layer using a pick-and-place machine, and the lead post is inserted into the lead hole.

[0044] Step S4: Check whether the pressure sensor chip and the lead post are fully mated.

[0045] Step S5: The pressure sensor chip is sintered and sealed onto the sintered housing.

[0046] Specifically, before encapsulating the pressure sensor chip, check the following: (1) Under a microscope, check whether the connection position between the leadless pressure sensor chip 3 and the lead post 14 of the sintered housing 1 is correct; (2) Check whether the conductive paste filling the inside is fully filled; (3) Check whether the sealing glass paste between the leadless pressure sensor chip 3 and the sintered housing is fully filled.

[0047] Specifically, the lead post 14 of the sintered tube shell is located on the end face 11 of the sintered tube shell 1. The sintered tube shell 1 of this application has a flat end face 11 and an insulating layer 13 (glass preform). The sealing paste (glass sealing paste) can be printed onto the insulating layer 13 of the sintered tube shell 1 by screen printing. After a certain volume of conductive paste 15 is filled into the four lead holes 31 of the leadless pressure sensor chip 3 with electrodes, the leadless pressure sensor chip 3 is attached to the insulating layer 13 of the sintered tube shell 1 by a chip mounter. The four exposed lead posts 14 of the sintered tube shell 1 are inserted into the four lead holes 31, so that the internal electrodes of the leadless pressure sensor chip 3 and the four lead posts 31 are electrically connected through the filled conductive paste 15. The glass layer of the leadless pressure sensor chip 3 is connected to the insulating layer 13 (glass preform) of the sintered tube shell through the printed sealing glass paste. Applying sealing glass slurry to the sintered tube shell via wire brushing is more convenient, and the thickness of the sealing glass slurry wire brush can be better controlled.

[0048] Step S6: Check whether the pressure sensor chip and the sintered shell are fully fitted after sintering.

[0049] Specifically, the following inspections are conducted after sintering: (1) After high-temperature sintering, the conductive paste can be inspected under a microscope to see if there are any voids after sintering; (2) Whether there are any cracks in the glass sealing paste between the chip and the sintered shell; (3) Whether there are any defects such as dirt or cracks in the sintered chip.

[0050] The leadless pressure sensor chip 3 is attached to the flat end face 11 and insulating layer 13 of the sintered tube shell 1. The pressure sensor chip 3 is fully exposed on the surface, which is conducive to the screen printing of the sealing glass paste and various inspections after the production operation.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A leadless packaged pressure sensor, characterized in that, The pressure sensor includes a sintered tube shell, a cover that cooperates with the sintered tube shell to form a receiving cavity, and a pressure sensor chip disposed in the receiving cavity. The cover includes an end cap and a first sidewall extending perpendicularly to the end cap along the edge of the end cap. The sintered tube shell includes an end face, a second sidewall extending perpendicular to the end face along the edge of the end face, an insulating layer disposed on the end face, and a lead post penetrating the end face and the insulating layer and extending along the direction of the second sidewall. The pressure sensor chip includes a glass layer, a metal layer and a silicon layer stacked sequentially on the insulating layer, with a lead hole located in the glass layer; The pressure sensor chip has lead holes that correspond one-to-one with the lead posts. The lead posts cooperate with the lead holes. The space between the lead holes and the lead posts is filled with conductive paste. The pressure sensor chip abuts against the insulating layer. There are four lead posts, corresponding to four lead holes; The lead hole is tapered and penetrates the glass layer. By filling the lead hole with the conductive paste, and cooperating with the lead post, the conductive paste can be connected to the metal layer and the lead post respectively, making the metal layer and the lead post conductive, and transmitting the electrical signal of the pressure change of the pressure sensor chip along the lead post. The silicon layer can sense changes in external temperature and deform at high temperatures. The metal layer can receive the deformation of the silicon layer and convert the deformation into an electrical signal. The sintered tube shell further includes a bottom surface extending from the end of the second sidewall away from the end face along a path close to the end of the lead post, the bottom surface being annular; and a third sidewall extending from the edge of the bottom surface away from the second sidewall toward the end face, the third sidewall surrounding the lead post and being parallel to the second sidewall. The lead posts of the sintered tube shell are located on the end face of the sintered tube shell. The sintered tube shell has a flat end face and an insulating layer. A sealing paste is printed onto the insulating layer of the sintered tube shell by screen printing. After the conductive paste is filled into the four lead holes with electrodes of the leadless pressure sensor chip, the leadless pressure sensor chip is attached to the insulating layer of the sintered tube shell by a pick-and-place machine. The four exposed lead posts of the sintered tube shell are inserted into the four lead holes. The internal electrodes of the leadless pressure sensor chip are electrically connected to the four lead posts through the filled conductive paste. The glass layer of the leadless pressure sensor chip is connected to the insulating layer of the sintered tube shell through the printed sealing paste.

2. The pressure sensor as described in claim 1, characterized in that, The sintered tube shell also includes a boss extending from the second sidewall toward the direction away from the lead post, and the side of the first sidewall away from the end cap abuts against the boss.

3. The pressure sensor as described in claim 2, characterized in that, The boss extends circumferentially along the second sidewall.

4. The pressure sensor as described in claim 2, characterized in that, The distance from the boss to the end face is less than the length of the first sidewall extending from the end cap.

5. The pressure sensor as described in claim 1, characterized in that, The end cap is provided with several through holes.

6. A method for packaging a leadless packaged pressure sensor, said method being based on the leadless packaged pressure sensor as described in any one of claims 1 to 5, characterized in that, The method includes: The sealing slurry is screen-printed onto the surface of the insulation layer of the sintered tube shell; The conductive paste is filled into the lead holes of the pressure sensor chip; The filled pressure sensor chip is attached to the printed insulating layer using a pick-and-place machine, and the lead post is inserted into the lead hole. The pressure sensor chip is sintered and sealed onto the sintered tube shell; Check whether the pressure sensor chip and the sintered tube shell are fully fitted after sintering.

7. The packaging method as described in claim 6, characterized in that, Before sintering and sealing the pressure sensor chip onto the sintered housing, the process also includes checking whether the pressure sensor chip and the lead post are fully fitted.

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