[0055] The embodiments of the present invention will be easily understood by those skilled in the
[0056] Throughout the specification and the appended claims, the term means that a particular use of certain system components. As those skilled in the art will appreciate, various companies may represent a component by different names. This document does not distinguish between different desired name but functionally identical components. In the claims, the term "including" and "comprising" is used open-ended fashion, and thus should be interpreted to mean "including, but not limited to ..." in the specification and the appended claims. Spatially relative terms such as "under ...", "... in the below", "lower", "beneath ...", "... in the above", "upper" and the like, in here may be used for convenience of description to describe the relationship of one element or such features shown in FIG other elements or features. It should be understood that in addition to the orientation shown in the figures, the spatial relationships also include different orientations of the devices in use and operations. For example, if the device in the drawings is flip, then "under other components" or "lower" or "under" or "lower" element or feature will be oriented to be in other components or feature "on". Therefore, exemplary terms "in ..." and "under ..." may include upper and lower orientations. The device can additionally orientation (rotate 90 degrees or other orientation) and the spatial descriptor used herein is correspondingly explained.
[0057] As used in this application and illustrated in the appended claims, unless the context clearly suggest exception, "a", "an", "an" and / or "the" are not specific singular words, also include the plural. In the following description of various embodiments of the content having one or more technical features, respectively, then this does not imply the use of any embodiment of the present inventors required a while all features in the embodiments, or only implemented separately in different embodiments part or all the technical features. In other words, under the premise of a possible embodiment, for disclosure to those skilled Keyijuben invention, depending on the design and implementation specifications or requirements, selectively embodiments some or all of the technical features of any one embodiment or selectively combining a plurality of embodiments embodiments some or all of the technical features of the embodiments, thereby increasing the elasticity of the embodiment when the present invention.
[0058] The following will be described below with reference to the drawings. figure 1 Is an exploded view of a pressure measuring module according to an embodiment of the present invention, figure 2 Is a schematic view of a pressure measuring module assembly according to an embodiment of the present invention, image 3 Embodiment of the present invention is to provide a pressure measurement module according to an embodiment schematic top view, Figure 4 Yes image 3 Pressure measurement module shown along the A-A sectional view of the connection, Figure 5 It is a schematic top view of a pressure measuring module provided in an epoxy matrix upon removal of the embodiment of the present invention.
[0059] like Figure 1 to 5 Shown embodiment the present invention provides a pressure measurement module 10 includes a substrate 11, 12, MEMS sensing element 13 epoxy resin matrix, an application specific integrated circuit chip 14 and the passive device 15. Wherein the ASIC chip 14 and the passive devices 15 are fixed on the surface of substrate 11. The upper surface of the substrate 11 with a specific distribution of metal pad (not shown, preferably the surface of the metal pad is provided with a nickel-gold plating), so that these components on the metal pad is fixedly connected to the corresponding. Here, the passive device 15 can be surface mounted on the substrate 11, and the ASIC chip 14 may be connected by flip-chip and the substrate 11 may be bound by a surface mount manner bonding wire 11 is connected to the substrate. In addition, the passive device 15 includes resistors, capacitors and other peripheral circuit components, which may be provided to enhance the performance of the pressure measuring EMC module 10, to ensure the reliability of pressure measurements. However, the present invention is a passive device for a particular number of 15, and the particular type of layout is not particularly restricted, the user can selectively set according to their needs, in order to meet their requirements.
[0060] Further, also known is the fixed component each provided on the substrate 11, it is to be understood as to achieve a mechanical and electrical interconnects on the substrate 11. In addition to these, in the selection of the substrate 11 is not limited to the PCB, the BT board, the LTCC board, the HTCC plate, metal thin film or thick film printing a ceramic sputtering plate. And, should be particularly noted that the present invention, use of an LGA package encapsulation technology pressure measuring module 10, for this purpose, such as Figure 4 As shown in the lower surface of the substrate 11 is provided a plurality of bare metal plane 111 (Pad), for electrically connecting with the outside, for example by binding or the like from the outside is electrically mounted embodiment, but the number of the metal plane 111 is not be limited to Figure 4 Three as shown, one skilled in the art from the line can be set according to actual needs and the particular number of flat metal 111, a distributed fashion.
[0061] Further, two MEMS sensing element 13, respectively connected to the communication ASIC chip 14 and, here, two MEMS sensing element 13 to achieve a communication connection with the ASIC chip 14 through the substrate 11. Thus, two MEMS sensor element 13 are sensing a measured pressure of the medium and fed back to the ASIC chip 14, two further pressure information specific integrated circuit chip 14 corresponding to the received digital processing, digital processing where including but not limited to temperature drift and non-linear compensation processing, arithmetic processing may also be another, for example two pressure operation information, and outputs the diagnostic information, or the two-way differential pressure information is converted into pressure, pressure, pressure ratio information the present invention is a digital processing manner is not limited, so that pressure measurements can be implemented in various forms to meet the various requirements of users measured, preferably, may be burned into the flexibly configure specific integrated circuit chip 14 digital processing by software, For example, in research and development side or client can burn themselves into the corresponding software, so more flexibility, more convenient to use.
[0062] Further, the inventors in order to overcome the thermal expansion coefficient of the MEMS sensor element of a thermal expansion coefficient of the substrate caused inconsistent effects on the pressure measurement, and therefore the two MEMS sensor element 13 is directly fixed on the epoxy resin matrix 12, instead of directly on the substrate 11, to avoid the MEMS sensing element 13 in contact with the substrate 11. Specifically, the epoxy resin matrix 12 is provided on the substrate 11, particularly an epoxy resin matrix 12 is formed, so that the substrate 11 may be provided on the epoxy resin matrix by inclusions 12 of ASIC chip 14 on the substrate 11 by an injection molding process, and All passive devices 15, so that components on the substrate surface to be protected, to prevent corrosion of these components in the harsh environment of the medium, to ensure that they work normally and stably. Meanwhile, two MEMS sensor element 13 are fixed to the base body 12 after the epoxy resin, but also to achieve the electrical interconnection to the substrate 11, and preferably by gold bond wire 16 is connected to the metal pads on the substrate 11 corresponding to . Here, an epoxy resin-based thermal expansion coefficient of the preferred body 12 for the MEMS sensor element of 1.0 to 3.0 times a thermal expansion coefficient of 13, and more preferably, a thermal epoxy resin matrix 12 expansion coefficient of less than 10ppm / C, thus, the base body 12 during use pressure measurement will not cause additional thermal stress, can better ensure that the pressure measurement accuracy.
[0063] Further, the present invention features two pressure measurement can be achieved MEMS sensor element 13 is not particularly limited, and any one of the two MEMS sensor element 13 may be an absolute pressure sensor element may be a relative pressure transmission sense element, for example, two MEMS sensor element 13 may be a combination of several ways:
[0064] 1, the absolute pressure sensor element opposite to the pressure sensing element; herein absolute pressure sensor element for measuring the absolute pressure of the medium, and the relative pressure sensor element for measuring a pressure difference between the different positions of the medium; for example, the absolute the pressure sensor element measuring the absolute pressure downstream of the particulate trap, the relative pressure sensor element and measuring the pressure between the particulate trap downstream of the above difference;
[0065] 2, absolute pressure sensor element and the absolute pressure sensor element; Here, two absolute pressure sensor element can measure both the absolute pressure measured at the location of the same medium, and the pressure signal redundancy check, different from each other can be measured absolute position measuring pressure medium, such as simultaneous measurement of absolute pressure downstream or upstream of the particulate trap, or a measurement of absolute pressure upstream of the particulate trap, the other downstream of the measurement of absolute pressure of the particulate trap;
[0066] 3, relative pressure sensor element opposite to the pressure sensing element; in combination with a second similar, two opposing pressure sensing element may be implemented redundancy check pressure signal may be measured independently of the pressure difference between the different positions .
[0067] Thus, by using a pressure measuring module according to an embodiment 10 of the present invention, the plurality of pressure measurements can be achieved, to meet the measurement requirements of various users. Further, the pressure measuring module 10 is achieved by injection molding the epoxy resin matrix 12 of the package, there are two internal integrated MEMS sensor element, a specific integrated circuit chip and a plurality of passive devices, and application specific integrated circuit chip may handle multiple pressure signal, to facilitate to achieve a plurality of pressure measurements, and therefore, not only highly integrated, compact, low cost, and good EMC performance, but also simplify the process of subsequent packaging and assembly.
[0068] Contraction below Figure 1 to 5 , Then a further explanation of the specific structure of the pressure measuring module 10.
[0069] Multiplex pressure information encoded in the embodiment, the ASIC chip 14 is preferably digitized embodiment of the present invention is a unilateral nibble (the SENT) digital communication protocol to multiplex pressure information output to an external circuit by the way, such as by a pin needle between the pressure output of the vehicle downstream of the particle catcher and upstream and downstream differential pressure controller, which can simplify the configuration of output ports, arranged connecting line is reduced, thereby simplifying the structure and reducing the cost.
[0070]Further, the ASIC chip 14 is preferably unpackaged die, which can reduce the package cost. Still further, the die in the form of ASIC chip 14 and the connection substrate 11, as described above, can be flip-chip way, surface mount manner may be used to bind the binding wire, in particular, ASIC chip 14 is surface mounted on the surface of the substrate 11, and connected by a gold bond wire 11 and the corresponding metal pads on the substrate.
[0071] Then reference Figure 5 , The substrate 11 having a central area and at the edge regions on both sides of the central region. Preferably, an application specific integrated circuit chip 14 and the passive devices 15 are disposed in the central region, and two MEMS sensing element 13 disposed facing the edge region and distributed at opposite sides of ASIC chip 14, which will help lower the package to achieve isolation of the measurement of the physical medium.
[0072] Further, the epoxy resin matrix 12 preferably is formed with two chambers 121, there is placed a MEMS sensor element 13 in each chamber 121, and further preferably in each chamber 121, and a high temperature potting protection gel curing the protective package so that the gel after curing chamber corresponding to a MEMS sensor element 13 and other associated components, other components include respective gold bond wire 16, and with gold bond wires 16 bound to at the metal pad, in order to improve the resistance to media devices. Preferably, a fluorine-containing protective silica gel, silica fluoride softer aspect, the pressure will not affect the normal transfer, on the other hand, silica fluoride has good resistance to the media, and can protect the sensor element and the connecting line point normal and stable work in the harsh media environment. More preferably, when the MEMS sensor element 13 connected to the substrate through the gold bond wires 16, at a position in the gold bond wires 16 and the metal pad with passivation binding glue is provided, preferably passivation the glue is an epoxy resin glue protection, in order to improve resistance to halogen bound connection.
[0073] Preferably, low pressure molding by way modified epoxy resin material is filled in the upper surface of the substrate 11, the substrate 11 and the whole package all the passive surface of the device 15 and the ASIC chip 14, so that the surface of the upper substrate components for epoxy resin, and epoxy resin matrix 12 is formed. Modified epoxy resin preferably contains a material of SiO2, 12 to ensure that the epoxy resin matrix having a small thermal expansion coefficient, to avoid the thermal stress effect, accurate measurement of the effects of stress.
[0074] Further, in order to facilitate mounting, the epoxy resin matrix 12 is formed in each of the injection chamber 121 preferably has a step 122, and step 122 is fixed on the MEMS sensing element 13, it can be fixedly bonded by silica. Optionally, a step 122 is formed in the concrete bottom (near substrate 11) of the chamber 121, and step 122 and the chamber 121 is reserved for the channel between the side walls, for gold bond wires 16 disposed through, so that the MEMS sensing element 13 is connected to the channel at the end of the metal pad.
[0075] In addition, reference Figure 4 , MEMS sensing element 13 when the relative pressure sensor element, two opposing surfaces on which strain of a diaphragm sensing measurements, respectively pressure of the medium, therefore, can be provided on the other through hole 1a of the substrate 11 on the step 122 communicating a through hole 1b, so that the measuring medium of the two communication through-hole 1a, 1b strain is introduced to the lower surface of the membrane (near substrate 11). When MEMS sensor element of an absolute pressure sensor element 13 due to its own internal chamber is provided with a vacuum chamber, thus (away from the surface of the substrate 11) using the strain on the surface of the membrane measuring absolute pressure sensing medium.
[0076] Next, embodiments of the present invention also provides a method for encapsulating a pressure measuring module 10, includes the following steps:
[0077] Step a: providing a substrate;
[0078] Step 2: Passive devices fixed on the upper surface of the substrate, and it is electrically connected to the substrate;
[0079] Step 3: ASIC chip is fixed on the surface of the substrate, and it is electrically connected to the substrate;
[0080] Step four: forming an injection device of the passive epoxy resin matrix on the substrate, and the epoxy resin matrix disposed on the package substrate and said ASIC chip;
[0081] Step Five: two MEMS sensor element is fixed on the epoxy matrix, and the two MEMS sensor element is connected through the substrate to communicate with the ASIC chip.
[0082] Further, preferably five-step process to achieve as follows:
[0083] When injection of the epoxy resin matrix is formed on the substrate, there are formed two chambers on the epoxy matrix;
[0084] Thereafter, a fixed element of the MEMS sensor in each chamber and connected to the MEMS sensing element and corresponding metal pads on a substrate binding by gold wires;
[0085] Then, each chamber Reperfusion gel and curing was performed, the protective wrapping gel corresponding to a MEMS sensor element chamber, gold bond wires and metal pads.
[0086] Further, prior to filling each chamber to protect the gel, further comprising: the substrate and the MEMS sensor element is bound to a position with an epoxy and curing was performed in order to improve binding connector the resistance to the halogen.
[0087] Still further, the three step procedure is preferably implemented as follows:
[0088] Providing unpackaged die, the die as a specific integrated circuit chip;
[0089] The surface of the die mounted on the surface of the substrate, and connected by the gold bond wire corresponding to the die pad and the substrate metal.
[0090] The next combination Image 6 More specifically, the encapsulation process pressure measuring module 10 preferably comprises the steps of:
[0091] Step 11: mount passive devices; in particular solder paste printed on the surface of a substrate, forming a plurality of metal pads and mounted on the surface of the substrate a passive device;
[0092] Step 12: Passive reflow fixing means;
[0093] Step 13: ASIC chip mounting (ASIC mount); specific use epoxy ASIC chip 14 mounted on the surface of the substrate;
[0094] Step 14: The ASIC chip and the substrate are electrically connected using gold bond wire;
[0095] Step 15: injection molding packaging; specific manner by low pressure molding on the surface of the substrate for the epoxy resin component and form two chambers;
[0096] Step 16: MEMS sensor element mount; DETAILED two MEMS sensor element is placed on and fixed to the stepped chamber;
[0097] Step 17: Use the gold bond wire MEMS sensor element is electrically connected with the substrate;
[0098] Step 18: Protection potting gel; silica gel into two fluorine perfusion chamber;
[0099] Step 19: high temperature curing protective gel;
[0100] Step 20: Calibration Test.
[0101] Finally, programming and calibration can be.
[0102] Preferably, prior to step 18, further comprising: on a substrate bound to the MEMS sensor element at a position epoxy coating and cured. I.e., is connected to the metal pad is coated with an epoxy glue in gold bond wire, to improve the resistance to a halogen bound connection.
[0103] Another Incidentally, the present embodiment described above, the preferred embodiment of the invention, but are not limited to the scope of the disclosed embodiments, the present invention is for example, MEMS sensor element arrangement on the epoxy resin matrix is not particularly limited as long as it does not contact with the substrate and can be connected by a gold bond wire electrically with the substrate, Furthermore, the present invention is connected to the ASIC chip and passively device and the substrate is not particularly limited.
[0104] In summary, an embodiment of the pressure measuring module 10 of the present invention may be connected to the outside, to achieve measurement of pressure, in particular suitable for measuring in aggressive environments, such as to achieve a pressure measurement in the exhaust emissions of the vehicle environment.
[0105] Compared with the prior art, the present invention provides a pressure measurement module comprises a substrate, two MEMS sensor element, an application specific integrated circuit chip and passive components, and implemented by injection molding packaging epoxy matrix, not only the high integration, structure compact, low cost, and good EMC performance (integrated passive devices), can also simplify assembly and subsequent packaging process, increase productivity, in particular, two measured pressure signal may be achieved, it can meet the user's various measurements Require.
[0106] Obviously, those skilled in the art can carry out various modifications and variations inventions without departing from the spirit and scope of the invention. Thus, the present invention also intends to include these modifications and variations if these modifications and variations of the invention are within the scope of the claims and equivalents of the present invention.
