Ambient temperature sensor capable of being coupled to a printed circuit board with an improved package

Abstract

An ambient temperature sensor capable of being coupled to a printed circuit board (PCB) having an improved package is provided. The ambient temperature sensor includes a package including a first cover and an insulating structure. The insulating structure is formed of a thermally insulating material, and the first cover and the insulating structure define a first cavity. A semiconductor device is included and generates an electrical signal indicative of temperature. The semiconductor device is secured to a top of the insulating structure and disposed within the first cavity. The package can be coupled to the PCB such that the insulating structure is interposed between the semiconductor device and the PCB. The insulating structure defines a second cavity that extends below the semiconductor device and is open laterally.

Description

Technical Field

[0001] The present disclosure relates to an ambient temperature sensor that can be coupled to a printed circuit board (PCB) and includes an improved package. Background Art

[0002] As is well known, it is now common to use temperature sensors on printed circuit boards (PCBs) to detect sudden, localized temperature increases. For example, a temperature sensor may be integrated into the PCB to detect the temperature near a heat source integrated into the PCB. In this case, the temperature sensor, formed by a corresponding integrated semiconductor circuit, is thermally coupled to the heat source.

[0003] That being said, there is currently a perceived need to be able to measure external, i.e., ambient, temperatures using PCB-mounted temperature sensors. In other words, there is a perceived need for temperature sensors that can be integrated into a PCB and enable accurate ambient temperature measurement. However, the packages used for PCB-mounted temperature sensors are typically not designed for optimal thermal coupling to the outside world. Furthermore, the measurements provided by the temperature sensor can be affected by heat sources on the PCB itself. Summary of the Invention

[0004] In various embodiments, the present disclosure provides an ambient temperature sensor that will at least partially overcome the shortcomings of the prior art.

[0005] In at least one embodiment, an ambient temperature sensor is provided that is coupleable to a printed circuit board (PCB). The ambient temperature sensor includes a package and a semiconductor device. The package includes a first cover and an insulating structure. The insulating structure is formed of a thermally insulating material, and the first cover and the insulating structure define a first cavity. The semiconductor device is configured to generate an electrical signal indicative of temperature, and the semiconductor device is secured to the insulating structure and disposed within the first cavity. The package is configured to be coupled to the PCB, wherein the insulating structure is interposed between the semiconductor device and the PCB, and defines a second cavity that extends below the semiconductor device and is open laterally.

[0006] In at least one embodiment, a system is provided that includes a printed circuit board (PCB) and a temperature sensor coupled to the PCB. The temperature sensor includes a package and a semiconductor device. The package includes a first cover and an insulating structure. The insulating structure is formed of a thermally insulating material, and the first cover and the insulating structure define a first cavity. The semiconductor device is configured to generate an electrical signal indicative of temperature, and the semiconductor device is secured to the insulating structure and disposed within the first cavity. The package is coupled to the PCB, wherein the insulating structure is interposed between the semiconductor device and the PCB, and the insulating structure defines a second cavity that extends below the semiconductor device and is open laterally.

[0007] In at least one embodiment, a method is provided that includes coupling a temperature sensor to a printed circuit board (PCB). The temperature sensor includes a package and a semiconductor device. The package includes a first cover and an insulating structure. The insulating structure is formed of a thermally insulating material, and the first cover and the insulating structure define a first cavity. The semiconductor device is configured to generate an electrical signal indicative of a temperature, and the semiconductor device is secured to the insulating structure and disposed within the first cavity. The package is coupled to the PCB, wherein the insulating structure is interposed between the semiconductor device and the PCB, and the insulating structure defines a second cavity that extends below the semiconductor device and is open laterally. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order that the present disclosure may be better understood, preferred embodiments thereof will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

[0009] Figure 1 is a schematic cross-sectional view of a temperature sensor coupled to a PCB;

[0010] Figure 2 yes Figure 1 a schematic perspective view of the sensor shown;

[0011] Figure 3 yes Figure 1 and Figure 2 a schematic perspective view of the sensor shown with portions removed;

[0012] Figure 4 yes Figures 1 to 3 a schematic top view with portions removed of the sensor shown; and

[0013] Figure 5 is a schematic cross-sectional view of a temperature sensor coupled to a PCB. DETAILED DESCRIPTION

[0014] Figure 1 and Figure 2 Indicates the temperature sensor 1 integrated in the PCB 2.

[0015] In particular, the temperature sensor 1 comprises a sensing device 4, which in turn comprises a die 6 of semiconductor material, within which are formed a sensitive area 8 and a processing circuit 10, the latter being formed, for example, by a corresponding application-specific integrated circuit (ASIC) and electrically coupled to the sensitive area 8. The sensitive area 8 is configured to change its electrical parameters, for example, as a function of the temperature to which it is subjected, to generate a corresponding electrical signal, which is processed by the processing circuit 10 to generate an output signal indicative of the temperature detected by the sensing device 4.

[0016] The temperature sensor 1 further includes a package body 20, which in turn includes a first cover 22 and a first insulating structure 24. The first cover 22 is formed, for example, of a metal material (for example, stainless steel) or an insulating material (for example, plastic or epoxy resin), and the first insulating structure 24 is formed, for example, of a thermally insulating material and an electrically insulating material (such as a material selected from ceramics, aluminum oxide or bismaleimide-triazine (BT) resin).

[0017] The first insulating structure 24 includes a body 34 having a parallelepiped shape and defined at the top and bottom by a top surface S1 and a bottom surface S2 , respectively.

[0018] The first cover 22 is placed on the first insulating structure 24 and is mechanically coupled to the top surface S1 so as to define, together with the first insulating structure 24, a cavity 26, hereinafter referred to as the die cavity 26. The die 6 is housed within the closed cavity 26 and is fixed to the top surface S1 of the first insulating structure 24, for example via glue or a so-called dry film of the die attach film (DAF) type or solder paste (not shown).

[0019] In more detail, temperature sensor 1 includes a fixing region 25 that ensures mechanical coupling between first cover 22 and first insulating structure 24. Fixing region 25 can be formed, for example, from glue or solder paste. Furthermore, fixing region 25 has an annular shape and is arranged on top surface S1, completely surrounding the bottom of first cover 22 in direct contact with top surface S1. This does not imply any loss of generality; first cover 22 lacks a hole, thereby enclosing die cavity 26.

[0020] A cavity 30 extends within the body 34 of the first insulating structure 24 and is hereinafter referred to as the decoupling cavity 30. The decoupling cavity 30 has essentially the shape of a parallelepiped, with four arms 35 extending within the parallelepiped. More specifically, the decoupling cavity 30 has an envelope (i.e., an encumbrance) shaped like a parallelepiped, defined at the top and bottom by a top inner surface S3 and a bottom inner surface S4, respectively. These top inner surface S3 and bottom inner surface S4 are planar and interposed at a distance between the top surface S1 and the bottom surface S2. The top surface S1, the bottom surface S2, the top inner surface S3, and the bottom inner surface S4 are parallel to one another.

[0021] The four arms 35 are formed in a single piece with the body 34 and, as previously described, extend within the decoupling cavity 30. This does not imply any loss of generality; the arms 35 have the same shape and each arm 35 extends from a corresponding peripheral edge of the arm 35, i.e., from a corresponding peripheral portion of the arm 35, towards the center of the decoupling cavity 30. In other words, the arms 35 form the shape of the decoupling cavity 30.

[0022] In addition, in the top view ( Figure 4 ), a first pair of arms 35 extends symmetrically at a distance along a first diagonal of the rectangular shape defined by decoupling cavity 30, while a second pair of arms 35 extends symmetrically at a distance along a second diagonal of the rectangular shape defined by decoupling cavity 30. Furthermore, arms 35 have a thickness equal to the distance between top inner surface S3 and bottom inner surface S4. In other words, each arm 35 is interposed between top inner surface S3 and bottom inner surface S4 in direct contact.

[0023] As in Figure 4 As can be seen again in FIG, die 6 is laterally staggered relative to arm 35; that is, it is located on a portion of body 34 that is laterally staggered relative to arm 35. Arm 35 provides mechanical support and robustness to the system during assembly (e.g., during die attach and wire bonding steps) and can constitute the site of an electrical link. Furthermore, arm 35 imparts rigidity, allowing decoupling cavity 30 to maintain its shape over time, and therefore maintain its ability to thermally decouple die 6 and PCB 2.

[0024] The decoupling cavity 30 has a transverse opening A facing the side wall P of the main body 34 of the first insulating structure 24. The transverse opening A places the decoupling cavity 30 in fluid communication with the outside.

[0025] The package body 20 further comprises a plurality of first pads 40 of conductive material extending below the bottom surface S2 and to be electrically connected to corresponding electrical terminals (not shown) present on the PCB 2. Furthermore, the package body 20 comprises a plurality of wire bonds 42 which enable connection via insertion of corresponding electrical links 44 ( Figure 1 2 ), connects corresponding conductive pads (not shown) present on die 6 to corresponding first pads 40, with the electrical links extending through body 34 of first insulating structure 24. In practice, wire bonds 42 each connect a corresponding conductive pad (not shown) of die 6 to a corresponding electrical link 44. Through wire bonds 42, electrical links 44, and first pads 40, processing circuit 10 can provide output signals to the outside world, in particular, to other electronic components (not shown) equipped with PCB 2.

[0026] In use, the bottom surface S2 of the body 34 of the first insulating structure 24 faces the PCB 2. Thus, the first insulating structure 24 is interposed between the PCB 2 and the die 6. Furthermore, due to the fact that the first insulating structure 24 is formed of a thermally insulating material, and due to the further insulating function provided by the decoupling cavity 30, good thermal decoupling is achieved between the sensing device 4 and possible heat sources present on the PCB 2. In particular, the decoupling is further improved by the presence of the lateral opening A in the first insulating structure 24, which enables air or other gaseous / liquid coolant to circulate within the decoupling cavity 30.

[0027] In this way, to a first approximation, the electrical signal generated by the sensitive area 8 is a function solely of the temperature of the air (or possibly the liquid) surrounding the first cover 22 (i.e., in a manner substantially independent of the heat generated by the components present on the PCB 2). The output signal provided by the processing circuit 10 is therefore effectively indicative of the temperature of the medium in which the temperature sensor 1 is arranged, without being influenced by heat sources present on the PCB 2.

[0028] Figure 5 Shows the reference relative to Figures 1 to 4 The differences between the illustrated embodiments are used to describe the different embodiments.

[0029] Package body 20 includes a second insulating structure 50, which includes a container 52 formed of, for example, an insulating material (such as a material selected from ceramic, alumina, or BT resin). Container 52 has the shape of a hollow parallelepiped open at the top. In other words, container 52 defines a cavity 55 at the bottom and laterally, hereinafter referred to as a coupling cavity 55.

[0030] In more detail, the container 52 includes a bottom wall 58 defined at the bottom and top by a first wall surface 59 and a second wall surface 60 , respectively.

[0031] Furthermore, first insulating structure 24 and first cover 22, and therefore die 6, are arranged in coupling cavity 55 such that bottom surface S2 of body 34 of first insulating structure 24 faces first wall surface 59. Specifically, first pads 40 are placed on first wall surface 59, making direct contact with first wall surface 59. In addition, second insulating structure 50 includes a plurality of second conductive pads 64 that are fixed to container 52 and extend below second wall surface 60.

[0032] The second conductive pads 64 are electrically connected to corresponding electrical terminals (not shown) present on the PCB 2 and to the corresponding first pads 40. Specifically, each second pad 64 is electrically connected to the corresponding first pad 40 via a corresponding electrical connector 66 that extends through the bottom wall 58 of the container 52. Thus, the output signal generated by the processing circuit 10 is provided to the PCB 2 via the second pads 64.

[0033] The second insulating structure 50 further includes a second cover 70 , which may have a planar shape, be formed of, for example, a thermally conductive material (eg, steel), and be mechanically coupled to the container 52 , for example, by glue or solder paste (not shown), so as to close the coupling cavity 55 .

[0034] In more detail, the second cover 70 is placed at a certain distance on the first cover 22. In addition, the second cover 70 is penetrated by a plurality of holes 72 ( Figure 5 Two of them are shown in the figure), these holes 72 have, for example, a cylindrical shape and connect the coupling cavity 55 to the external fluid.

[0035] In practice, the presence of the second insulating structure 50 further improves the thermal decoupling between the sensitive area 8 of the sensing device 4 and the PCB 2. In practice, in addition to the first insulating structure 24, a portion of the container 52 made of insulating material (particularly the bottom wall 58) is inserted between the PCB 2 and the die 6. Furthermore, the hole 72 enables gas / liquid exchange between the outside world and the coupling cavity 55, thereby improving the thermal coupling between the outside world and the sensing device 4.

[0036] The advantages provided by the present temperature sensor are clearly apparent from the foregoing description. Specifically, the present temperature sensor includes a package that enables its integration on a PCB while ensuring good thermal insulation of the temperature sensing device from heat sources present on the PCB, thereby enabling accurate measurement of the temperature of the medium (fluid) in which the temperature sensor is located.

[0037] Finally, it is clear that modifications and variations may be made to what has been described and illustrated herein without departing from the scope of the present disclosure.

[0038] For example, the electrical coupling between the die 6 and the first pads 40 and, if present, the second pads 64 can be different from the electrical coupling already described between the die 6 and the first pads 40 and, if present, the second pads 64. For example, instead of wire bonds 42, the die 6 can be coupled to the electrical link 44 through the body 34 of the first insulating structure 24 via bumps (not shown) disposed below the die 6.

[0039] Likewise, different types of electrical terminals may be used in place of the conductive pads.

[0040] The decoupling cavity 30 may have more than one side opening.

[0041] Finally, the number and shape of arms 35 may differ from those already described; arms 35 may even be absent.

[0042] The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments in light of the above detailed description. Generally, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments and the full scope of equivalents to which such claims are entitled. Therefore, the claims are not limited by the disclosure.

Claims

1. An ambient temperature sensor capable of being coupled to a printed circuit board (PCB), the ambient temperature sensor comprising: a package body comprising a first cover and an insulating structure having a body, the insulating structure being formed of a thermally insulating material, and the first cover and the insulating structure defining a first cavity; as well as a semiconductor device configured to generate an electrical signal indicative of temperature, the semiconductor device being fixed on the insulating structure and disposed within the first cavity; The package body is configured to be coupled to the PCB via the insulating structure, the insulating structure being inserted between the semiconductor device and the PCB, and wherein the insulating structure defines a second cavity arranged within the body of the insulating structure, the second cavity extending below the semiconductor device and being laterally open. 2 . The temperature sensor according to claim 1 , wherein the second cavity is closed along a direction of the semiconductor device and the PCB. 3 . The temperature sensor of claim 1 , wherein the insulating structure is defined by a front surface and a rear surface, the front surface being interposed between the semiconductor device and the rear surface, and wherein the second cavity extends a distance between the front surface and the rear surface.

4. The temperature sensor according to claim 3, further comprising: A plurality of first electrical terminals are electrically connected to the semiconductor device and extend on the rear surface.

5. The temperature sensor according to claim 4, further comprising: A plurality of electrical links extend at least partially within the insulating structure and are configured to electrically connect the semiconductor device to the first electrical terminal.

6. The temperature sensor according to claim 1, wherein the package further comprises: a container of thermally insulating material, the container defining a third cavity, the first cover, the insulating structure, and the semiconductor device being arranged inside the third cavity, and wherein the package is configured to be coupled to the PCB through a portion of the container, the portion of the container being interposed between the insulating structure and the PCB.

7. The temperature sensor according to claim 6, further comprising: A plurality of second electrical terminals are electrically connected to the semiconductor device and fixed to the container, wherein the second electrical terminals are configured to be coupled to the PCB.

8. The temperature sensor according to claim 6, wherein the package further comprises: A second cover encloses the third cavity and is penetrated by at least one aperture configured to place the third cavity in fluid communication with an external environment. 9 . The temperature sensor of claim 1 , wherein the first cover has no holes and is formed of a thermally conductive material.

10. The temperature sensor according to claim 1, wherein the second cavity is defined by a top inner surface and a bottom inner surface at the bottom and the top, respectively, and wherein the insulating structure includes at least one arm having an elongated shape and extending from a peripheral portion of the second cavity toward a central portion of the second cavity, the arm being interposed between the top inner surface and the bottom inner surface in direct contact. 11 . The temperature sensor of claim 1 , wherein the semiconductor device comprises a die, an application specific integrated circuit being formed in the die.

12. An electronic system comprising: Printed circuit board PCB; as well as a temperature sensor coupled to the PCB, the temperature sensor comprising: a package body comprising a first cover and an insulating structure having a body, the insulating structure being formed of a thermally insulating material, the first cover and the insulating structure defining a first cavity; and a semiconductor device configured to generate an electrical signal indicative of temperature, the semiconductor device being fixed on the insulating structure and disposed within the first cavity; The package body is coupled to the PCB via the insulating structure, the insulating structure is inserted between the semiconductor device and the PCB, and the insulating structure defines a second cavity arranged within the body of the insulating structure, the second cavity extending below the semiconductor device and opening laterally.

13. The system of claim 12, wherein the insulating structure is defined by a front surface and a back surface, the front surface being interposed between the semiconductor device and the back surface, and wherein the second cavity extends a distance between the front surface and the back surface.

14. The system of claim 13, further comprising: a plurality of first electrical terminals electrically connected to the semiconductor device and extending on the rear surface; as well as A plurality of electrical links extend at least partially within the insulating structure and are configured to electrically connect the semiconductor device to the first electrical terminal.

15. The system of claim 12, wherein the package further comprises: a container of thermally insulating material, the container defining a third cavity, the first cover, the insulating structure, and the semiconductor device being arranged inside the third cavity, and wherein the package is coupled to the PCB through a portion of the container, the portion of the container being interposed between the insulating structure and the PCB.

16. The system of claim 15, further comprising: A plurality of second electrical terminals are electrically connected to the semiconductor device and fixed to the container, wherein the second electrical terminals are configured to be coupled to the PCB.

17. The system of claim 15, wherein the package further comprises: A second cover encloses the third cavity and is penetrated by at least one aperture configured to place the third cavity in fluid communication with an external environment.

18. The system of claim 12, wherein the second cavity is defined at the bottom and top by a top inner surface and a bottom inner surface, respectively, and wherein the insulating structure comprises at least one arm having an elongated shape and extending from a peripheral portion of the second cavity toward a central portion of the second cavity, the arm being interposed in direct contact between the top inner surface and the bottom inner surface.

19. A method for arranging a temperature sensor, comprising: The temperature sensor is coupled to a printed circuit board PCB, wherein the temperature sensor comprises: a package body comprising a first cover and an insulating structure having a body and formed of a thermally insulating material, the first cover and the insulating structure defining a first cavity; and a semiconductor device configured to generate an electrical signal indicative of temperature, the semiconductor device being fixed on the insulating structure and disposed within the first cavity; The package body is coupled to the PCB via the insulating structure, the insulating structure is inserted between the semiconductor device and the PCB, and the insulating structure defines a second cavity arranged within the body of the insulating structure, the second cavity extending below the semiconductor device and opening laterally.

20. The method of claim 19, further comprising: A plurality of electrical links are electrically connected between the semiconductor device and a plurality of first electrical terminals extending on a rear surface of the insulating structure, the plurality of electrical links extending at least partially within the insulating structure.

Images