JP3173006U - Sensor element - Google Patents

Abstract

A sensor element is provided that is not damaged in subsequent processing processes.
A sensor element includes a conductive structure, a sensor chip disposed on and connected to the conductive structure, and a sensor chip configured such that the sensor element has a rectangular parallelepiped shape. And the inlet part 14 of the encapsulation part 1 reaching the surface part 21 of the sensor chip 2. The inlet portion 14 is disposed at the center of the upper surface 12 of the sensor element, and further includes a lower surface 11 of the sensor element opposite to the upper surface 12, and the lower surface 11 is covered with the capsule sealing portion 1. The plurality of regions of the conductive structure 3 are not included, and these regions include a region 31 disposed in the center and four regions disposed on the edge side.
[Selection] Figure 2

Description

  The present invention relates to a sensor element.

  Sensor elements today often include a sensor chip, on which the actual sensor function is mounted or incorporated in the form of components or structures with high measurement sensitivity. Here, the substrate may be a semiconductor substrate such as silicon, for example, and a circuit function unit such as an electronic evaluation circuit is similarly incorporated in the substrate.

  An example of such a sensor chip is described in EP1236038B1 of the applicant's patent document 1.

  Unprotected sensor chips can be damaged in subsequent processing processes. Also, the electrical connection structure of the sensor chip is usually inappropriate and cannot be directly connected to a circuit support such as a conventional printed circuit board.

  In this respect, the sensor chip is advantageously provided with a so-called “package”, which in most cases encapsulates the sensor chip with a plastic casting. In the present invention, the sensor chip thus encapsulated is also referred to as a sensor element.

EP1236038B1

  An object of the present invention is to provide a sensor element that is not damaged in subsequent processing processes.

  The invention relates to a sensor element as described in the characterizing part of claim 1. The sensor element includes a conductive structure and a sensor chip. The sensor chip is disposed on the conductive structure and is conductively connected to the conductive structure. The sensor chip encapsulation portion is provided so that the sensor element has a rectangular parallelepiped shape. The entrance portion of the encapsulation portion that reaches the surface portion of the sensor chip is disposed at the center of the upper surface of the sensor element. The lower surface of the sensor element opposite to the upper surface has a plurality of regions of the conductive structure that are not covered by the encapsulation, and these regions are located in the center and on the edge. And four arranged regions.

  Advantageously, the edge region is used as an electrical connection for the sensor element. In this case, such a sensor element can easily be arranged on the circuit support. This circuit support has, for example, a corresponding part in the metallized area. In this case, the region on the circuit support side can be connected to the conductor path of the circuit support at least with respect to the connection portion of the sensor element. Advantageously, the region configured as a connection point for this sensor element is connected to a connection point on the circuit support via a conductive adhesive such as solder paste.

  The geometry of the small area that is exposed to the sensor element is advantageous for achieving a compact structure of the sensor element, while at the same time providing good electrical insulation between the connections and a large area in the center. Through this area, the heat generated in the sensor chip can be released to the outside. Furthermore, the central entrance to the upper surface of the sensor element provides the shortest possible connection from the periphery of the sensor element to the sensitive surface portion of the sensor chip. The diagonally cut corners of the lower surface of the sensor element, in particular the central area of the rectangular shape, are optically sensitive to incorrect orientation of the sensor element in the sense that it protects optical orientation errors during its installation. Can be used as protection. This is because, inter alia, the rectangular shape and the inlet portion arranged in the center and configured symmetrically make it difficult to orient correctly during installation. In this respect, a sensor element is realized which is protected from damage during subsequent processing and is extremely compact and less susceptible to external influences.

  Advantageous developments of the invention are described in the dependent claims.

  Further embodiments, advantages and applications of the invention emerge from the dependent claims and the following description based on the drawings.

1 is a perspective view of a lower surface of a sensor element according to an embodiment of the present invention. 1 is a perspective view of an upper surface of a sensor element according to an embodiment of the present invention. It is sectional drawing of the sensor element by one Example of this invention. It is a top view of the sensor element lower surface by one Example of this invention. It is a top view of the sensor element side by one Example of this invention. It is a top view of the sensor element side by one Example of this invention. It is a top view of the sensor element upper surface by one Example of this invention.

  FIG. 1a) shows a perspective view of a lower surface 11 of a sensor element according to one embodiment of the present invention. This sensor element basically has a rectangular parallelepiped shape, and this shape is mainly defined by the molding of the encapsulation portion 1. In this embodiment, the encapsulating part 1 is regarded as a sensor chip and a cast structure of a conductive structure provided inside. Here, as shown below, the sensor chip does not necessarily need to be completely encapsulated, nor does it need to be invisible or touchable. The same can be said for the relationship between the encapsulation part and the conductive structure. In any case, this encapsulation part substantially protects the sensor chip and simplifies handling of the sensor element. The encapsulation part 1 can be produced by a transfer molding method or another casting method. Advantageously, the encapsulation part 1 is made of plastic.

  Further regions 31 and 32 are visible on the lower surface 11 of the sensor element, and these regions are exposed regions of the conductive structure, that is, regions not covered by the encapsulation portion 1. Advantageously, the conductive structure is a structure of a conductor track, also referred to as a lead frame, which is typically only a framework of the conductor track and does not include a support, preferably by copper. Have been made. According to an advantageous development, such a conductor track structure is etched from a metal strip. Here, advantageously, the metal strip can be etched in various regions of the metal strip from above and below until the thickness of the metal strip is halved, respectively. As a result, the conductor track structure has two different vertical plane conductor tracks. Further, for example, such a conductor track structure may be processed by metal coating or noble metal coating to protect the conductor track structure. According to another development, the conductive structure may be made by stamping a metal strip as a punched grid.

  Advantageously, the sensor chip is arranged on a conductive structure. The conductive structure and the sensor chip are almost poured into, for example, ensuring that the regions 31 and 32 of the conductive structure remain insulated from each other by the casting material.

  The region 31 having a large area is arranged at the center of the lower surface 11 of the sensor element, that is, this region extends at least on the center of the lower surface 11. This center can be regarded as an intersection of diagonal lines of the rectangle when the shape of the lower surface 11 is a rectangle as in this example. According to this embodiment, the central region 31 is in the form of a rectangle having two longitudinal sides and two lateral sides.

  One of the corners of the central region 31 is cut obliquely. This diagonally cut corner is used as a visual landmark in this example, which allows the sensor element to be accurately positioned when mounting the sensor element on or on the circuit support. It will be easy. Advantageously, the central region 31 of the conductive structure is formed with a large area, in particular the area is at least twice as large as the area of each region 32 arranged at the edge. In particular, a sensor chip not shown in FIG. 1 is mounted on the central region 31 and is preferably adhered to the central region 31 by means of an adhesive having good thermal conductivity, for example. Is used for heat dissipation. The heat generated from the sensor chip can be transferred to region 31 and optionally discharged to a heat sink on the circuit support via further thermal coupling. Such a large area 31 is also referred to as a “pad”. The sensor element can also have a predetermined potential via this “pad”. On the other hand, this “pad” can also keep the sensor chip in place and be mechanically stable.

  The region 32, which is arranged at the edge and has a somewhat smaller area relative to the region 31, is a region of a conductive structure, in particular a conductor track structure, which is not covered, ie not entirely covered by the encapsulation 1. Here, the edge side means that the region 32 is disposed outside the region 31 disposed in the center and is more or less disposed near the edge of the lower surface 11 of the sensor element. However, all of the edge regions 32 are in this embodiment arranged somewhat offset inward rather than directly in contact with the edges of the sensor element forming the boundary of the lower surface 11.

  Typically, the lower surface 11 of the sensor element is placed on a circuit support and is conductively connected. For example, the soldering flux is applied in advance to the area of the circuit support that works together with the areas 31 and 32, whereby an electrical contact is formed between the circuit support and the sensor element via the soldering flux. Is done.

  FIG. 1 a) further shows two side surfaces 13 of the sensor element. The side surface 13 also has unstructured conductive structures 33 and 34.

  Regarding the production of the sensor element, at least the sensor chip is arranged on the conductive structure until the encapsulation part 1 is formed by a casting process.

  Advantageously, a plurality of sensor elements are manufactured simultaneously in one common manufacturing process. For this purpose, it is possible to provide a single component consisting of a conductor track structure for a large number of sensor elements, which conductor track structures are connected to one another or have not yet been separated from one another. A sensor chip is placed in the region 31 having a large area of the structure, and is electrically connected to the structure. Thereafter, the entire structure is cast together with all the sensor chips. Subsequently, the individual sensor elements are cut off by sawing, whereby the areas 33, 34, for example arranged on the side surfaces, are automatically exposed.

  According to FIG. 1b), an inlet 14 is shown on the upper surface 12 of the sensor element leading to the surface part of the sensor chip. The inlet portion 14 is also arranged in the center of the upper surface 12 of the sensor element, and the capsule sealing portion 1 has a recessed portion or an opening portion. The central arrangement of the inlet portion 14 is again determined by the intersection of the diagonal lines of the rectangular upper surface 12.

  FIG. 2 shows a cross-sectional view of a sensor element according to one embodiment of the present invention. For example, the sensor element may be the sensor element of FIG. In this case, the cross section of FIG. 2 is a cross section that passes through the middle of the sensor element, and this cross section is not the section 31 cut along the longitudinal direction, but the section 31 cut along the width of the area 31.

  This sectional view shows a central region 31 of the conductive structure 3, and the sensor chip 2 is attached on the central region 31 via an adhesive layer 4. The sensor chip 2 has a measurement structure such as a measurement layer on the surface portion 21 thereof, and this measurement structure is formed as a polymer layer or a ceramic layer, for example, in the case of a humidity sensor. Can be absorbed. In this respect, it is advantageous if the surface part 21 is in contact with the surrounding environment of the sensor element via the inlet 14 or the fluid surrounding the sensor element can reach this surface part 21. It is. For this purpose, the encapsulation part 1 has a recess in the form of an opening that reaches the surface part 21 at the location of the inlet part 14. According to this example, the opening has a circular shape and is tapered in the direction of the sensor chip 2, that is, has a conical structure. Such recesses can be achieved during casting, for example by a suitably formed casting configuration. Furthermore, the sensor element can have a bonding wire, through which the sensor chip starts from its connection point and reaches its upper surface to be electrically connected to the conductor path of the conductive structure. These bonding wires are connected to the conductive structure after mounting the sensor chip and then cast together during casting.

  FIG. 3a) shows a plan view of the underside of a sensor element according to one embodiment of the present invention. FIG. 3b) shows a side view of a sensor element according to an embodiment of the present invention. FIG. 3c) shows a side view of a sensor element according to an embodiment of the present invention. FIG. 3d) shows a top view of the sensor element according to one embodiment of the present invention.

  Starting from FIG. 3d), this sensor element, which may be the same as the sensor element of FIGS. 1 and 2, is a sensor element having a rectangular bottom surface. The rectangle has a length d and a width b, where d = b. According to this development, both the length d and the width b are 2 mm.

  On the lower surface 11 of the sensor element of FIG. 3a), the central area 31 with a large area has a length l1 of at least 1 mm, for example 1.6 mm, and the width b1 of the central area 31 is at least 0.5 mm. For example, 0.7 mm. Any edge region of the plurality of edge regions 32 used as electrical connection points has a length l2 of at least 0.2 mm, preferably 0.3 mm, and at least 0.2 mm, preferably It has a width b2 of 0.25 mm. The distance a2 between the two regions 32 arranged in the longitudinal plane of the region 31 is at least 1 mm, preferably a2 = 1.27 mm, from the center of one region 32 to the center of the other region 32. . Advantageously, no region 32 is in direct contact with the end edge of the lower surface 11 of the encapsulation 1. Thereby, the distance r2 between such regions 32 and edges is preferably greater than 0.01 mm, particularly preferably 0.1 mm. The length e1 of one side of the corner 31 of the region 31 which is cut obliquely is preferably 0.2 mm.

  FIGS. 3b) and 3c) show two side surfaces 13 of the sensor element that are bordering each other, each side surface 13 having two regions 33, 34, respectively. The side 13 of FIG. 3b) has two regions 33 of height h3 that are closely arranged, which corresponds to half the height / thickness of the conductor track structure. In other words, it is preferably about 0.075 mm. The width b3 of the region 33 is preferably greater than 0.1 mm, particularly preferably 0.2 mm. The two regions 33 are separated from each other by 0.5 mm, preferably inside. The side surface 13 of FIG. 3c) has two other regions 34 of height h4 that are spaced apart from each other, which also corresponds to half the height / thickness of the conductor track structure. In other words, it is preferably about 0.075 mm. The width b4 of the region 34 is preferably greater than 0.2 mm, particularly preferably 0.4 mm. The two regions 34 are preferably separated from each other by a4 = 0.87 mm inside.

  While the present application describes advantageous embodiments of the present invention, the present invention is not limited to these embodiments and may be implemented in a manner different from that set forth within the scope of the following claims. Obviously you can.

  DESCRIPTION OF SYMBOLS 1 Encapsulation part, 2 Sensor chip, 3 Conductive structure, 4 Adhesion layer, 11 Lower surface, 12 Upper surface, 13 Side surface, 14 Entrance part, 21 Surface part, 31 Area | region arrange | positioned in the center, 32 Area | region of edge part, 33 Region, 34 region, interval between a2 regions 32, interval between a4 regions 34, length of rectangular bottom surface, width of b1 region 31, width of b2 region 32, width of b3 region 33, b4 region 34 The width of the bottom surface of the rectangle, the side of the corner of the e1 region 31 that is cut obliquely, the height of the h sensor element, the height of the h3 region 33, the height of the h4 region 34, the length of the l1 region 31 L2 The length of the region 32, and the distance between the r2 region 32 and the edge

Claims (25)

-Conductive structure (3);
A sensor chip (2) disposed on the conductive structure (3) and conductively connected to the conductive structure (3);
-The encapsulation part (1) of the sensor chip (2) configured so that the sensor element has a rectangular parallelepiped shape;
An inlet part (14) of the encapsulation part (1) reaching the surface part (21) of the sensor chip (2),
The inlet portion (14) is arranged at the center of the upper surface (12) of the sensor element,
Furthermore, the lower surface (11) of the sensor element opposite to the upper surface (12) is provided,
The lower surface (11) has a plurality of regions (31, 32) of the conductive structure (3) not covered by the encapsulation part (1),
The plurality of regions (31, 32) include a region (31) disposed in the center and four regions (32) disposed on the edge side.   The sensor element according to claim 1, wherein the encapsulating part is a plastic casting agent.   Sensor element according to claim 1 or 2, wherein the inlet (14) is formed as an opening of the encapsulation (1).   The inlet (14) is formed as a circular opening, in particular as a conical opening extending towards the surface portion (21) of the encapsulation (1). 4. The sensor element according to any one of items 1 to 3. The upper surface (12) and the lower surface (11) of the sensor element are formed in a rectangular shape,
The sensor element according to any one of claims 1 to 4, wherein the inlet (14) is arranged at an intersection of diagonal lines of the rectangular upper surface (12).   The sensor element according to claim 5, wherein the sensor element has a rectangular bottom surface of 2 mm × 2 mm, and the height (h) of the sensor element is smaller than 1 mm.   The sensor element according to any one of claims 1 to 6, wherein the conductive structure (3) is formed as a conductor path structure produced by etching.   The sensor element according to any one of claims 1 to 7, wherein the sensor chip (2) is disposed on the region (31) disposed in the center.   The connection location arranged on the same surface of the sensor chip (2) as the uncovered surface portion (21) is conductively connected to the conductor path of the conductive structure (3) via a bonding wire, The sensor element according to claim 1, wherein the bonding wire is cast and formed in the encapsulation part (1).   10. The sensor element according to claim 1, wherein the region (31) arranged in the center of the conductive structure (3) is rectangular.   11. The sensor element according to claim 10, wherein a corner of the rectangular region (31) arranged in the center of the conductive structure (3) is cut obliquely.   The length (l1) of the region (31) disposed in the center of the conductive structure (3) is at least 1 mm, and the width (b1) of the region (31) disposed in the center is at least 0.5 mm. The sensor element according to claim 10 or 11.   13. A sensor element according to any one of the preceding claims, wherein the edge region (32) of the conductive structure (3) is used as a connection location for an electrical contact of the conductive structure (3).   14. A sensor element according to any one of the preceding claims, wherein the length (l2) and the width (b2) of each edge region (32) of the conductive structure (3) are each at least 0.2 mm.   15. A sensor element according to any one of the preceding claims, wherein an edge region (32) of the conductive structure (3) is arranged in each quadrant of the lower surface (11) of the sensor element.   The sensor element according to claim 10, wherein two edge regions (32) are arranged on each side surface of the major diameter side of the region (31) arranged in the center.   17. The sensor according to claim 1, wherein the exposed area (31, 32) of the lower surface (11) of the sensor element does not reach an edge that forms a boundary with the lower surface (11). element.   At least one side surface (13) connecting the upper surface (12) and the lower surface (11) of the sensor element is at least one that is not covered by the encapsulation part (1) of the conductive structure (3). 18. Sensor element according to any one of the preceding claims, having two regions (33, 34).   19. A sensor element according to claim 18, wherein each region (33, 34) that is exposed on the side surface (13) does not reach an edge that forms a boundary with the lower surface (11). The rectangular parallelepiped sensor element has four flat side surfaces (13),
20. Each side (13) has at least one region (33, 34) of the conductive structure (3) that is not covered by the encapsulation (1). Sensor element.   21. Sensor element according to claim 20, wherein each side surface (13) has two regions (33, 34) of the conductive structure (3) that are not covered by the encapsulation (1). . The uncovered regions (33, 34) of the two opposite sides (13) have the same cross-section;
22. Sensor element according to claim 20 or 21, wherein the uncovered regions (33, 34) of adjacent side surfaces (13) have different cross sections.   The region (31, 32) of the lower surface (11) not covered by the encapsulation part (1) is composed of one region (31) disposed at the center and four regions disposed at the edge. 23. A sensor element according to any one of the preceding claims, comprising a region (32).   24. Sensor according to any one of claims 1 to 23, wherein the surface part (21) of the sensor chip (2) has a layer, which layer is used to absorb fluid around the sensor element. element.   The sensor element according to any one of claims 1 to 24, wherein the sensor element is a humidity sensor.

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