Semiconductor module and semiconductor device

Abstract

This semiconductor module (1) comprises: a module substrate (10) that has a first surface (10A), and a second surface (10B) that is on the opposite side from the first surface (10A); a first electronic component group (21) that is mounted on an outer peripheral portion of the first surface (10A); and an external output electrode group (20) for mounting the module substrate (10) on an external substrate (30), the external output electrode group (20) being disposed on the first surface (10A) closer to the central portion of the module substrate (10) than the outer peripheral portion on which the first electronic component group (21) is mounted.

Description

Semiconductor Module and Semiconductor Device

[0001] The present invention relates to a semiconductor module and a semiconductor device.

[0002] In order to increase the capacity and functionality of semiconductor devices, semiconductor modules have been put into practical use by mounting electronic components on both sides of a wiring board, molding them with resin, and integrating them into one package to increase the integration density.

[0003] For example, in Patent Document 1, in a semiconductor module with BGA (Ball Grid Array) type packaging, a semiconductor chip is mounted in the central region of one surface of the wiring board, and a group of conductor post pins is arranged on the outermost periphery of the one surface, and solder balls serving as external terminals are mounted on the surfaces of these conductor post pins exposed from the surface of the mold resin.

[0004] JP-A-2016-25198

[0005] Such semiconductor modules are mounted on a system or other modules by electrically joining the conductor post pins to an external PCB (Printed Circuit Board) substrate by soldering or the like. However, there is a problem that stress is applied to the electrical joints due to the tension caused by the difference in the linear expansion coefficients between the semiconductor module and the PCB substrate to be mounted, or the bending of the substrate caused by the balance of stresses within the module, resulting in a decrease in the reliability of the electrical joints. At this time, the farther the conductor post pins are provided from the center of the module, the greater the stress applied to the joints, so there is a particular problem of disconnection from the joints at the outer peripheral portion.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to improve the reliability of electrical joints in a semiconductor module.

[0007] A semiconductor module according to one aspect of the present invention comprises a module substrate having a first surface and a second surface opposite to the first surface; a group of first electronic components mounted on the outer periphery of the first surface; and a group of external output electrodes for mounting the module substrate to an external substrate, the external output electrodes being located on the first surface closer to the center of the module substrate than the outer periphery on which the group of first electronic components is mounted.

[0008] According to the present invention, it is possible to improve the reliability of electrical junctions in semiconductor modules.

[0009] This is a plan view of the first surface of a semiconductor module according to the first embodiment. This is a cross-sectional view of the semiconductor module according to the first embodiment along the line II-II. This is a plan view of the second surface of a semiconductor module according to the first embodiment. This is a cross-sectional view of a semiconductor device in which the semiconductor module according to the first embodiment is bonded to an external substrate. This is a cross-sectional view of the semiconductor module according to the first embodiment when the second surface is sealed with a top cover. This is a plan view of the first surface of a semiconductor module according to the second embodiment. This is a plan view of the first surface of a semiconductor module according to a modified example of the second embodiment.

[0010] Embodiments of the present invention will be described below with reference to the drawings. The drawings of this embodiment are illustrative, and the dimensions and shapes of each part are schematic; the technical scope of the present invention should not be limited to this embodiment.

[0011] <First Embodiment> First, the configuration of the semiconductor module 1 according to the first embodiment of the present invention will be described with reference to Figures 1 to 5. Each drawing may be accompanied by a Cartesian coordinate system consisting of the X, Y, and Z axes for convenience in order to clarify the relationships between the drawings and to help understand the positional relationships of each component. The directions parallel to the X, Y, and Z axes are referred to as the X-axis direction, Y-axis direction, and Z-axis direction, respectively. The plane defined by the X and Y axes is referred to as the XY plane (the same applies to other planes). For convenience, the positive Z-axis direction (direction of the arrow) will be described as up or upward, and the negative Z-axis direction (opposite direction of the arrow) will be described as down or downward, but the orientation of the semiconductor module 1 is not limited to these.

[0012] Figure 1 is a plan view of the semiconductor module 1 according to the first embodiment, viewed from the first surface (downward in the Z-axis direction). Figure 2 is a cross-sectional view of the semiconductor module 1 according to the first embodiment. Figure 3 is a plan view of the semiconductor module 1 viewed from the second surface (upward in the Z-axis direction). Figure 4 is a cross-sectional view of a semiconductor device in which the semiconductor module according to the first embodiment is bonded to an external substrate 30. Note that the resin mold portion and wires are omitted from the illustration in Figures 1, 3, 6, and 7.

[0013] The semiconductor module 1 comprises a module substrate 10, a plurality of external output electrode groups 20 arranged on a first surface 10A, a plurality of electronic component groups 21 mounted on the outer periphery of the first surface 10A, and a semiconductor component 22 mounted on the central part of the first surface. Here, the central part on which the semiconductor component 22 is mounted includes the center of the first surface and does not necessarily refer only to the position where the center of the first surface 10A and the center of the semiconductor component 22 overlap in the XY plane. The outer periphery on which the electronic component group 21 is mounted refers to the area of ​​the first surface 10A excluding the central part. The outer periphery on which the electronic component group 21 is mounted may be an area with a predetermined width from the outer edge of the first surface 10A, or it may be an area with a predetermined width from inside the outer edge of the first surface 10A.

[0014] The module substrate 10 comprises a first surface 10A and a second surface 10B, which are opposing main surfaces. The first surface 10A is the bottom surface, and the second surface 10B is the top surface. The material of the module substrate 10 is not particularly limited, but it may be a composite substrate of organic and inorganic materials such as a glass epoxy substrate, or it may be an organic material such as a resin substrate. The electronic component group 21 and the external output electrode group 20 are mounted on the first surface 10A of the module substrate 10, respectively. As illustrated in Figure 1, the module substrate 10 is, for example, rectangular in shape.

[0015] The electronic component group 21 comprises multiple electronic components. The electronic component group 21 is mounted on the outer periphery of the first surface 10A. The electronic component group 21 may include passive elements such as resistors and capacitors, or active elements such as semiconductor chips. The arrangement of the electronic component group 21 is not limited to the configuration disclosed in Figure 1. For example, it is not necessary to arrange them around the entire circumference of the outer periphery; they may be arranged on a part of the outer periphery, such as two opposing sides in the Y direction or two opposing sides in the X direction. In order to balance the stress inside the semiconductor module 1, it is desirable that any of the electronic components in the electronic component group 21 be arranged symmetrically in the XY plane (for example, plane symmetry with respect to the center of the XY plane, or line symmetry with respect to the axis in the X or Y direction). Furthermore, it is desirable that the electronic component group 21 be composed of components of the same size. In addition, the electronic component group 21 may be composed of low-profile components. This makes it possible to reduce the thickness of the semiconductor module 1 and achieve cost reduction. Furthermore, at least some of the electronic component group 21 may have a lower height in the Z-axis direction than the semiconductor component 22.

[0016] Furthermore, by arranging the electronic component group 21 on the outer periphery of the module substrate 10, the heat generated by the electronic component group 21 can be efficiently released to the outside of the module.

[0017] An external output electrode group 20 is provided on the side of the module substrate 10 closer to the center than the outer periphery where the electronic component group 21 is mounted. The external output electrode group 20 is for electrically connecting the various electronic components mounted on the module substrate 10 to the external substrate 30 (see Figure 4). The external output electrode group 20 has a plurality of external output electrodes. Any external output electrode of the external output electrode group 20 is electrically connected to any electronic component mounted on the module substrate 10. The plurality of external output electrodes may be arranged in an array such that the pitch between adjacent electrodes is at a constant interval. The external output electrode group 20 is, for example, a post pin, and the material used is copper or the like. The surface of the external output electrode group 20 on the first surface 10A side may be provided with a plating layer to improve conductivity. In the embodiment illustrated in Figure 1, for example, the external output electrode group 20 is arranged in a frame shape on the first surface 10A of the module substrate 10. Furthermore, both the electronic component group 21 and the external output electrode group 20 may be arranged to avoid the corner portions on the first surface 10A of the module substrate 10. The arrangement of the external output electrode group 20 is not limited to the configuration shown in Figure 1; for example, if the semiconductor component 22 is not mounted, it may be provided in the center of the first surface 10A or in a region including the center. In addition, apart from the example shown in Figure 1, the electronic component group 21 may be provided in a region including any corner portion of the first surface 10A.

[0018] When heat is applied to the module substrate 10 and the external substrate 30, such as the system substrate on which the module is mounted, during the manufacturing process, they expand and contract due to temperature changes. Generally, if the coefficients of thermal expansion of the semiconductor module 1 and the external substrate 30 are different, the difference in the amount of expansion and contraction of each will cause tension on the electrical junction. As a result, the further away from the center of the semiconductor module 1, the greater the stress on the electrical junction of the external output electrode group 20. Due to this stress caused by the difference in coefficients of thermal expansion and the deflection of the substrate due to internal stress on the module substrate 10, the stress on the junction further away from the center of the module is greater, reducing the reliability of the electrical junction. In this embodiment, the reliability of the electrical junction between the semiconductor module 1 and the external substrate 30 is improved by arranging the external output electrode group 20 to avoid the outer periphery of the substrate surface where stress is greatest and the corners of the module substrate 10 where the most stress is present.

[0019] Furthermore, a semiconductor component 22 may be mounted in the central part of the first surface 10A, which is inside the external output electrode group 20. The semiconductor component 22 is, for example, an MCU (Micro Controller Unit). In the embodiment illustrated in Figure 1, one large semiconductor component 22 is located in the central part of the first surface 10A. In this embodiment, the external output electrode group 20 is arranged between the central part on which the semiconductor component 22 is mounted and the outer periphery on which the electronic component group 21 is mounted. In this case, by placing the semiconductor component 22 in the central part of the first surface 10A, the stress balance within the semiconductor module 1 can be maintained better compared to when it is placed on one side of the first surface 10A in the X or Y direction. There may be multiple semiconductor components 22 mounted. In this case as well, if they can be arranged symmetrically in the X or Y direction, the stress balance within the semiconductor module 1 can be maintained.

[0020] In this embodiment, the circuit design on the first surface 10A may handle only digital signals and not analog signals. This reduces the influence of parasitic capacitance, which occurs depending on the distance between the group of electronic components 21 on the outer periphery and the semiconductor component 22, on the product characteristics.

[0021] A clearance is provided between the semiconductor component 22 and the external output electrode group 20. For example, the relationship between the distance L1 between the semiconductor component 22 and the external output electrode group 20 in Figure 1 and the distance L2 between adjacent external output electrodes in the external output electrode group 20 may be such that L1 ≥ L2. This makes it possible to alleviate the stress on the electrical junction located near the semiconductor component 22 caused by the difference in the coefficient of thermal expansion between the semiconductor component 22 and the module substrate 10.

[0022] Electronic components 23 may be mounted on the second surface 10B of the module board 10. For example, a MEMS (Micro Electro Mechanical Systems) sensor, an ASIC (Application Specific Integrated Circuit), etc., may be mounted. In the embodiment illustrated in Figure 3, a 3-axis acceleration MEMS sensor 23a (hereinafter, MEMS sensor 23a), a 3-axis gyroscope MEMS sensor 23b (hereinafter, MEMS sensor 23b), and an ASIC 23c are mounted. In this embodiment, the MEMS sensor 23a and the ASIC 23c, and the MEMS sensor 23b and the module board 10 are electrically connected by wires 24. The MEMS sensor 23a and the MEMS sensor 23b output the detected acceleration and angular velocity as analog voltages, respectively. The ASIC23c drives each MEMS sensor, amplifies the sensor output signal from each MEMS, corrects for temperature characteristics, converts it into a digital signal, and outputs the sensor data as a digital signal to an external system via a communication interface.

[0023] As described above, in this embodiment, the semiconductor module 1 functions as an inertial sensor module, but it is not limited to this, and may be, for example, a pressure sensor module or the like.

[0024] In this embodiment, both the sensor and an ASIC or other element capable of converting the sensor output into a digital signal are mounted on the second surface 10B, and the analog signal is converted to a digital signal on the second surface 10B. Generally, the longer the wiring within the module, the greater the parasitic capacitance, and the greater the impact on the analog signal in the circuit. However, in this embodiment, with the above configuration, it is possible to design a circuit that does not handle analog signals on the first surface 10A. Therefore, the impact of parasitic capacitance on the first surface 10A on the product characteristics can be reduced.

[0025] In this case, as shown in Figure 3, it is desirable that the two MEMS sensors 23a, 23b and the ASIC 23c be arranged along a center line C that passes through the midpoint in the X-axis direction of the second surface 10B and is aligned with the Y-axis direction. In this case, the centers of the MEMS sensors 23a, 23b and the ASIC 23c may coincide with the center line C. By arranging each component along such a center line C, it is possible to balance the stress that may occur in the semiconductor module 1. Furthermore, in order for the MEMS sensors 23a and 23b to detect the three axes of X, Y, and Z, it is desirable that the three sensitivity axes of the two MEMS sensors 23a and 23b be arranged along the X-axis, Y-axis, and Z-axis, respectively. By aligning the sensitivity axis of the entire semiconductor module 1 with the sensitivity axes of the MEMS sensors 23a and 23b in this way, interference of forces between the sensitivity axes can be suppressed, thereby improving the accuracy of the sensors. In addition, the interpretation of measurement data becomes easier. Furthermore, in a plan view of the second surface 10B, the group of electronic components 23 mounted on the second surface 10B may be mounted so as to fit within the outer shape of the area where the external output electrode group 20 is arranged on the first surface 10A.

[0026] Figure 4 shows a semiconductor device 3 in which the semiconductor module 1 is mounted on an external substrate 30. As in this embodiment, the semiconductor module 1 is mounted on the external substrate 30 by electrically joining the external output electrode group 20 to the PCB substrate of the system or other modules. In this embodiment, soldering 26 is used as the electrical joining method, but the joining method is not limited to this.

[0027] The semiconductor module 1 may be packaged in a surface-mount package such as an LGA (Land Grid Array) or BGA. As for the sealing method, for example, as shown in Figures 2 and 4, the first surface 10A is sealed with a resin mold 11. When the first surface 10A is sealed with resin, the external output electrode group 20 is manufactured by, for example, shaving the first surface 10A from the bottom (downward in the Z-axis direction) after resin sealing to expose the external output electrode group 20 so that it can be electrically connected to the outside. The second surface 10B may also be sealed with resin, or it may be sealed with a top cover 40 as illustrated in Figure 5, but the sealing method is not limited. For example, a metal cover member may be used for the top cover 40. When a metal cover member is used, electromagnetic waves inside and outside the semiconductor module can be blocked by the shielding effect. In addition, a magnetic material-containing sheet may be attached to the inside of the top cover 40.

[0028] As described above, according to this embodiment, the module substrate 10 has a first surface 10A and a second surface 10B which is the opposite surface of the first surface 10A, a group of electronic components 21 mounted on the outer periphery of the first surface 10A, and a group of external output electrodes 20 for mounting the module substrate 10 to an external substrate 30, the group of external output electrodes 20 being located on the first surface 10A closer to the center of the module substrate 10 than the outer periphery on which the group of electronic components 21 is mounted.

[0029] This eliminates the need to place the external output electrode group on the outer periphery of the substrate, where electrical connections are prone to coming loose, thereby improving the reliability of the electrical connections in the external output electrode group 20.

[0030] Furthermore, in this embodiment, the external output electrode group 20 is arranged in a frame shape on the first surface 10A of the module substrate 10.

[0031] Furthermore, in this embodiment, the module substrate 10 is further equipped with a semiconductor component 22 mounted in the central part of the first surface 10A, and the external output electrode group 20 is arranged on the first surface 10A between the central part on which the semiconductor component 22 is mounted and the outer peripheral part on which the electronic component group 21 is mounted.

[0032] According to this, it is not necessary to place the external output electrode group 20 on the outer periphery of the substrate where electrical connections are prone to coming loose, thereby improving the reliability of the electrical connections in the external output electrode group 20, and also enabling the balancing of stress within the semiconductor module 1.

[0033] Furthermore, in this embodiment, the distance L1 between the semiconductor component 22 and the external output electrode group 20 and the distance L2 between adjacent external output electrodes in the external output electrode group 20 are such that L1 ≥ L2.

[0034] According to this, it is possible to alleviate the stress on the electrical junction located near the semiconductor component 22, which is caused by the difference in the coefficient of thermal expansion between the semiconductor component 22 and the module substrate 10.

[0035] Furthermore, this embodiment also includes a group of electronic components 23 mounted on the second surface 10B of the module substrate 10.

[0036] Furthermore, in this embodiment, the module substrate 10 has a rectangular shape, and both the group of electronic components 21 and the group of external output electrodes 20 are arranged to avoid the corners on the first surface 10A of the module substrate 10.

[0037] According to this, by arranging the external output electrode group 20 while avoiding the corners of the module substrate 10, which are subjected to the most stress, the reliability of the electrical connection between the semiconductor module 1 and the external substrate 30 can be improved.

[0038] Furthermore, in this embodiment, the external output electrode group 20 of the semiconductor module 1 may be soldered to the external substrate 30, thereby forming a semiconductor device.

[0039] In subsequent embodiments, descriptions of matters common to the first embodiment will be omitted, and only the differences will be explained. In particular, similar effects and benefits due to similar configurations will not be mentioned sequentially for each embodiment.

[0040] <Second Embodiment> Next, the structure of the semiconductor module 2 according to the second embodiment will be described with reference to Figure 6. Figure 6 is a plan view of the first surface of the semiconductor module 2 according to the second embodiment.

[0041] As shown in FIG. 6, the semiconductor module 2 further includes a dummy electrode 25A disposed on the outer peripheral side of the external output electrode group 20 at the corner portion of the first surface 10A. The dummy electrode 25A is an electrode that is not electrically connected to the electronic components mounted on the module substrate 10. The dummy electrode 25A may be made of the same material as the external output electrodes of the external output electrode group 20. The dummy electrode 25A is electrically joined to the external substrate 30. As the joining method, for example, soldering or the like is used in the same manner as the external output electrode group 20.

[0042] According to the present embodiment, the reliability of the electrical connection between the external output electrode group 20 and the external substrate 30 can be further enhanced. In the present embodiment, the dummy electrode 25A is provided at the corner portion of the module substrate 10 where the electrical connection is most likely to come off. Thereby, when the electrical connection comes off, it comes off from the connection of the dummy electrode 25A portion, and the risk of the electrical connection portion of the external output electrode group 20 coming off can be reduced. Also, while the dummy electrode 25A does not come off, the dummy electrode 25A contributes to strengthening the electrical connection force particularly at the outermost peripheral portion, and plays a role of protecting the external output electrode group 20 from coming off.

[0043] Also, in order to enhance the reliability of the electrical connection, for example, increasing the diameter of the external output electrode group 20 can be considered. However, in this case, it hinders the miniaturization of the module and causes problems such as cost increase. On the other hand, in the present embodiment, the reliability of the electrical connection can be enhanced without increasing the size of the module.

[0044] Also, as a modification, as shown in FIG. 7, the dummy electrode 25A may be a dummy electrode 25B that is larger than any of the external output electrodes of the external output electrode group 2,500. According to this, in the corner portion that is easily affected by stress, the joining force between the module substrate 10 and the external substrate 30 can be improved, so that the reliability of the electrical connection of the semiconductor module can be enhanced.

[0045] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention can be modified or improved without departing from its spirit, and equivalents thereof are also included. That is, any design modifications made to each embodiment by a person skilled in the art are also included within the scope of the present invention, as long as they retain the features of the present invention. For example, the elements and their arrangement, materials, conditions, shapes, sizes, etc., of each embodiment are not limited to those exemplified and can be modified as appropriate. Furthermore, each embodiment is illustrative, and it goes without saying that partial substitution or combination of the configurations shown in different embodiments is possible, and these are also included within the scope of the present invention as long as they retain the features of the present invention.

[0046] 1...Semiconductor module according to the first embodiment 2...Semiconductor module according to the second embodiment 3...Semiconductor device 10...Module substrate 10A...First surface 10B...Second surface 11...Resin mold 20...External output electrode group 21...Electronic component group 22...Semiconductor component 23...Electronic component group 23a...3-axis accelerometer MEMS sensor 23b...3-axis gyroscope MEMS sensor 23c...ASIC 24...Wire 25A, 25B...Dummy electrodes 26...Solder joint 30...External substrate 40...Top cover C...Center line L1...Distance L2...Distance

Claims

1. A semiconductor module comprising: a module substrate having a first surface and a second surface opposite to the first surface; a group of first electronic components mounted on the outer periphery of the first surface; and a group of external output electrodes for mounting the module substrate to an external substrate, the external output electrodes being positioned on the first surface closer to the center of the module substrate than the outer periphery on which the first electronic components are mounted.

2. The semiconductor module according to claim 1, wherein the group of external output electrodes is arranged in a frame shape on the first surface of the module substrate.

3. The semiconductor module according to claim 1 or 2, further comprising a semiconductor component mounted on the central part of the first surface of the module substrate, wherein the external output electrode group is arranged on the first surface between the central part on which the semiconductor component is mounted and the outer peripheral part on which the first electronic component group is mounted.

4. The semiconductor module according to claim 3, wherein the distance L1 between the semiconductor component and the group of external output electrodes and the distance L2 between adjacent external output electrodes of the group of external output electrodes are such that L1 ≥ L2.

5. The semiconductor module according to any one of claims 1 to 4, further comprising a second group of electronic components mounted on the second surface of the module substrate.

6. The semiconductor module according to any one of claims 1 to 5, wherein the module substrate is rectangular in shape, and both the first group of electronic components and the group of external output electrodes are arranged to avoid the corners on the first surface of the module substrate.

7. The semiconductor module according to claim 6, further comprising a dummy electrode disposed at the corner portion of the first surface of the module substrate.

8. The semiconductor module according to claim 7, wherein the dummy electrode is larger than any of the external output electrodes in the group of external output electrodes.

9. The semiconductor module according to any one of claims 1 to 8, wherein the second surface of the module substrate is sealed by a metal cover member.

10. A semiconductor device comprising: a semiconductor module according to any one of claims 1 to 9; and an external substrate, wherein the group of external output electrodes of the semiconductor module is soldered to the external substrate.

Images