Semiconductor devices

Abstract

The present invention discloses a semiconductor device, which includes a metal substrate, a metal frame, a semiconductor element, a feedthrough and a metal side plate. The semiconductor element is mounted on the metal substrate in a space defined by the metal substrate and the metal frame. The feedthrough is inserted into a cutout of the metal frame and includes wiring, a lower block on which the wiring is mounted, and an upper block mounted on the lower block. The combined cross-sectional shape of the lower block and the upper block is a protruding shape. A portion of the upper block is located inside the space. The metal side plate is arranged between the side surface of the feedthrough and the cutout of the metal frame. The metal side plate has a protruding shape and covers the entire side surface of the feedthrough.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based upon and claims the benefit of priority from Japanese patent application No. 2018-113200, filed on Jun. 13, 2018, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a semiconductor device. Background Art

[0004] In the field of semiconductor devices, electronic components such as semiconductor elements can be hermetically sealed so as to be protected from moisture and foreign matter. Signal input and output relative to the sealed electronic components are performed via feedthroughs. In such a hermetically sealed package, due to temperature changes, a protruding-shaped feedthrough made of aluminum oxide is subjected to stress from a metal wall surrounding the feedthrough and cracks are generated, so that airtightness may be lost. JP2012-038837A discloses a structure in which the thickness of the upper portion of the feedthrough is formed to be greater than the thickness of the metal wall in order to prevent loss of airtightness. Summary of the invention

[0005] The present disclosure provides a semiconductor device. The semiconductor device includes a metal substrate, a metal frame, a semiconductor element, a feedthrough and a metal side plate. The metal frame is placed on the metal substrate. The metal frame is provided with at least one cutout penetrating the metal frame. The semiconductor element is mounted on the metal substrate in a space defined by the metal substrate and the metal frame. The feedthrough is inserted into the cutout of the metal frame and mounted on the metal substrate. The feedthrough includes wiring, a lower block and an upper block. The wiring is configured to electrically connect the semiconductor element located inside the space with an electrical component located outside the semiconductor device. The lower block is made of ceramic and the wiring is mounted thereon. The upper block is made of ceramic and is mounted on the lower block. Along the mounting direction of mounting the upper block on the lower block, the combined cross-sectional shape of the lower block and the upper block is a protruding shape. A portion of the upper block is located inside the frame. The metal side plate is disposed between a side surface of the feedthrough extending along an extending direction of the wiring and the cutout of the metal frame. The metal side plate has a protruding shape and covers an entire side surface of the feedthrough. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The foregoing and other objects, aspects and advantages will be better understood from the following detailed description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0007] Figure 1 is a plan view of a semiconductor device according to a first embodiment;

[0008] Figure 2 It is along Figure 1 A cross-sectional view of the semiconductor device taken along line II-II in FIG.

[0009] Figure 3 is a view illustrating a feedthrough and a pair of side plates in the semiconductor device according to the first embodiment;

[0010] Figure 4 is a view of a feedthrough of the semiconductor device according to the first embodiment as viewed from the inside;

[0011] Figure 5 is a perspective view showing a feedthrough member bonded by a side plate in a semiconductor device according to a second embodiment. and

[0012] Figure 6 is a perspective view showing a feedthrough bonded by a side plate in a semiconductor device according to a third embodiment. DETAILED DESCRIPTION

[0013] [Problems to be solved by the present disclosure]

[0014] The semiconductor device disclosed in JP2012-038837A can reduce stress concentrated on the connection point between the lower portion of the feedthrough and the upper portion of the feedthrough. However, in semiconductor devices for satellites or semiconductor devices equipped with high-power semiconductor elements, it has been required to more reliably prevent the occurrence of cracks caused by severe temperature conditions and thermal cycles with large temperature changes.

[0015] [Beneficial Effects of the Present Disclosure]

[0016] According to the present disclosure, it is possible to provide a semiconductor device in which cracks generated in a feedthrough due to temperature changes are prevented.

[0017] [Description of Embodiments of the Present Disclosure]

[0018] An embodiment of the present disclosure will be described. A semiconductor device according to an embodiment of the present disclosure includes a metal substrate, a metal frame, a semiconductor element, a feedthrough, and a metal side plate. The metal frame is placed on the metal substrate. The metal frame is provided with at least one cutout that penetrates the metal frame. The semiconductor element is mounted on the metal substrate in a space defined by the metal substrate and the metal frame. The feedthrough is inserted into the cutout of the metal frame and mounted on the metal substrate. The feedthrough includes wiring, a lower block, and an upper block. The wiring is configured to electrically connect the semiconductor element located inside the space with an electrical component located outside the semiconductor device. The lower block is made of ceramic, and the wiring is mounted thereon. The upper block is made of ceramic and is mounted on the lower block. Along the mounting direction of mounting the upper block on the lower block, the combined cross-sectional shape of the lower block and the upper block is a protruding shape. A portion of the upper block is located inside the frame. The metal side plate is arranged between the side surface of the feedthrough, which is expanded along the extension direction of the wiring, and the cutout of the metal frame. The metal side plate has a protruding shape and covers the entire side surface of the feed-through. With this configuration, cracks can be prevented from being generated in the feed-through due to temperature changes.

[0019] As an embodiment, the metal side plate may be made of copper. Since the upper block and the lower block of the feedthrough made of ceramic are in contact with the metal frame made of metal through the side plate made of copper and having a small Young's modulus, this configuration can alleviate the stress received by the feedthrough from the metal frame.

[0020] As an embodiment, the metal side surface plate may further include a triangular reinforcement portion that fills the first step of the side plate. The first step may be located inside the space. With this structure, the stress applied to the joint between the upper block made of ceramic and the lower block made of ceramic of the feedthrough may be further alleviated.

[0021] As an embodiment, the feedthrough may further include a triangular prism-shaped reinforcement portion filling the second step of the feedthrough. The second step may be located inside the space. With this structure, the joint between the upper block made of ceramic and the lower block made of ceramic of the feedthrough is reinforced by the triangular reinforcement portion, so that the influence of stress can be further reduced.

[0022] As an embodiment, the metal side plate may have a thickness of at least 300 μm. With this configuration, the stress received by the feedthrough from the metal frame may be substantially relieved.

[0023] As an embodiment, the semiconductor device may include at least one circuit located inside the metal frame. The wiring of the feedthrough may be configured to electrically connect the semiconductor element to the electrical component via the at least one circuit.

[0024] As an embodiment, the semiconductor device may further include another feedthrough inserted into another cutout of the metal frame and mounted on the metal substrate. In this embodiment, the other feedthrough may include: another wiring configured to electrically connect the semiconductor element to another electrical component located outside the semiconductor device; another lower block made of ceramic and on which the wiring is mounted; and another upper block made of ceramic and mounted on the other lower block. Along the installation direction of mounting the other upper block on the other lower block, the combined cross-sectional shape of the other lower block and the other upper block may be a protruding shape, and a portion of the other upper block may be located inside the metal frame. In this embodiment, the feedthrough, the semiconductor element, and the other feedthrough may be arranged along a straight line.

[0025] As an embodiment, the semiconductor device may further include another side plate covering the entire opposite side surface of the feed-through.

[0026] [Details of Embodiments of the Present Disclosure]

[0027] Hereinafter, details of an embodiment of a semiconductor device according to the present disclosure will be described with reference to the accompanying drawings. In the following description, components represented by the same reference numerals in different drawings are the same, and in some cases, their descriptions may be omitted. In addition, the present invention is not limited to the examples in these embodiments, but includes all modifications within the scope and equivalent scope of the subject matter described in the claims. In addition, the present invention includes any combination of embodiments, as long as a combination of multiple embodiments is possible.

[0028] [First embodiment]

[0029] Figure 1 is a plan view of a semiconductor device according to a first embodiment of the present disclosure, Figure 2 It is along Figure 1 A cross-sectional view of a semiconductor device taken along line II-II in FIG. Figure 1 and Figure 2 As shown in , the semiconductor device 100 includes a metal base 10, a metal frame 20, a cover (lid) 40, an input side branch circuit 31, an output side multiplexing circuit 35, an input matching circuit 32, an output matching circuit 34, a semiconductor chip 33 and two feedthroughs 50. Figure 1 This is a view obtained by observing through the cover 40.

[0030] The metal substrate 10 is formed by: 2On the surface of the metal having a three-layer structure of Cu (copper) / Mo (molybdenum) / Cu (copper), electroplating is performed using, for example, Ni (nickel) / Au (gold). As the material of the metal base 10, for example, Kovar, CuW (copper tungsten), CuMo (copper molybdenum), etc. can be used, and the surface can be plated with Au, Ni, Ag (silver), Ag-Pt (platinum), Ag-Pb (lead), etc. The recess 11 is formed at four places on both sides of the X-axis direction of the metal base 10, and screws for mounting and fixing the metal base 10 on the substrate are inserted.

[0031] A metal frame 20 made of, for example, Kovar is disposed on the upper side (positive side in the Z-axis direction) of the metal base 10, and the upper side of the metal frame 20 is covered by a cover 40, which is made of Kovar similar to the metal frame 20. As a metal material of the metal frame 20 and the cover 40, CuW, CuMo, etc. can be used instead of Kovar. The cutouts 21 are respectively disposed substantially at the center of the two walls of the metal frame 20 facing the Y-axis direction, and feedthroughs 50 for input and output are respectively inserted into the two cutouts 21. In the present embodiment, the metal base 10, the metal frame 20, the cover 40, and the feedthrough 50 constitute a package.

[0032] Of the two feedthroughs 50, for example, the feedthrough located on the negative side in the Y-axis direction is a feedthrough 50 for input, and the feedthrough located on the positive side in the Y-axis direction is a feedthrough 50 for output. A wiring pattern 53 is formed in each feedthrough 50. Each of the wiring patterns 53 extends along the Y-axis direction.

[0033] As an electronic component housed in the package, a semiconductor chip 33 including a field effect transistor (FET) constructed by using, for example, a nitride semiconductor, and an input matching circuit 32 for input impedance adjustment and an output matching circuit 34 for output impedance adjustment are mounted so that the semiconductor chip 33 is placed between the input matching circuit 32 and the output matching circuit 34. In addition, an input side branch circuit 31 and an output side multiplexing circuit 35 are arranged outside the input matching circuit 32 and the output matching circuit 34, respectively. Since the width of the semiconductor chip 33 is larger than the wiring pattern 53 that becomes an input terminal or an output terminal, the input side branch circuit 31 and the output side multiplexing circuit 35 are provided to equally distribute input signals to the corresponding FETs and equally collect outputs from the FETs into the output terminals.

[0034] The electronic components of the input side branch circuit 31, the input matching circuit 32, the semiconductor chip 33, the output matching circuit 34, and the output side multiplexing circuit 35 are mounted on the upper surface of the metal base 10, and in the XY plane, the metal frame 20 surrounds these electronic components. These electronic components are sealed in an airtight manner by the metal base 10, the metal frame 20, the cover 40, and the feedthrough 50. In the semiconductor device 100, the feedthrough 50, the input side branch circuit 31, the input matching circuit 32, the semiconductor chip 33, the output matching circuit 34, and the output side multiplexing circuit 35 are arranged along the Y-axis direction, which is a straight line.

[0035] The wiring pattern 53 of the feedthrough 50 for input and the input side branch circuit 31, the input side branch circuit 31 and the input matching circuit 32, the input matching circuit 32 and the semiconductor chip 33, the semiconductor chip 33 and the output matching circuit 34, the output matching circuit 34 and the output side multiplexing circuit 35, and the output side multiplexing circuit 35 and the wiring pattern 53 of the feedthrough 50 for output are respectively electrically connected by bonding wires 30. The bonding wires 30 are made of, for example, a metal such as Au. The wiring pattern 53 is a component for electrically connecting the semiconductor chip 33 to an electrical component located outside the semiconductor device 100 via the input side branch circuit 31 and the input matching circuit 32 or via the output matching circuit 34 and the output side multiplexing circuit 35. In addition, a back electrode is formed on the semiconductor chip 33, and the potential of the back electrode is lowered to the ground potential through the metal substrate 10.

[0036] The wiring pattern 53 located on the outer side of the metal frame 20 on the two feedthroughs 50 is provided with a lead (not shown). For example, a radio frequency (RF) signal is input to the wiring pattern 53 from one of the two leads (on the negative side in the Y-axis direction), and the RF signal is output from the other of the two leads (on the positive side in the Y-axis direction). In addition, the bias voltage of the FET of the semiconductor chip 33 is input to the lead. The feedthrough 50 acts as a transmission line, and the RF signal flows through the feedthrough 50. The semiconductor device 100 acts as an amplifier that amplifies the RF signal, for example.

[0037] Figure 3 1 is a view showing a feedthrough and a pair of side plates in the semiconductor device according to the first embodiment. Figure 41 is a view of a feedthrough in a semiconductor device according to a first embodiment observed from the inside. The feedthrough 50 includes, for example, a lower block 51 made of ceramic such as alumina (Al2O3), a wiring pattern 53 formed on the upper surface of the lower block 51, and an upper block 52 made of ceramic. The width W2 of the upper block 52 in the Y-axis direction is formed to be larger than the width W1 of the wall of the metal frame 20, and the width of the lower block 51 in the Y-axis direction is formed to be larger than the width W2 of the upper block 52. The upper block 52 is arranged at the central part of the Y-axis direction of the lower block 51, and the two are formed integrally. Therefore, the cross-sectional shape of the lower block 51 and the upper block 52 along the YZ plane, that is, along the direction (Z-axis direction) perpendicular to the extension direction (Y-axis direction) of the wiring pattern 53 of the feedthrough 50) is protruding. A pair of side plates 60 are respectively provided on the entire surface of the two side surfaces in the X-axis direction of the feedthrough 50 to serve as a buffer material. Each of the side plates 60 has a protruding shape, and is composed of a metal plate made of, for example, Cu.

[0038] The side plate 60 preferably has a thickness of 300 μm or more, and is bonded to the side surface of the feedthrough 50 made of alumina by a brazing material made of silver (Ag), copper (Cu), nickel (Ni), etc. The feedthrough 50 bonded with the side plate 60 is inserted into the opening formed by the cutout 21 of the metal base 10 and the metal frame 20. For example, an Ag brazing material is set in advance between the feedthrough 50 bonded with the side surface plate 60 and the opening, and the feedthrough 50 is fixed in the opening formed by the cutout 21 of the metal base 10 and the metal frame 20 by heating. At this time, as Figure 4 As shown in FIG. 2 , at least the upper block 52 is arranged to protrude into the space on the inner side of the metal frame 20. That is, the inner portion of the upper block 52 is located inside the metal frame 20. In addition, when the feed-through 50 is fixed, a brazing material or an adhesive is also provided between the metal frame 20 and the metal base 10, and the three components of the metal base 10, the metal frame 20 and the feed-through 50 are fixed.

[0039] Herein, when stress analysis is performed by using thermal expansion, for example, when the side plate 60 is not set to Figure 4 In the case where the feedthrough 50 shown in the figure and the width W2 of the upper block 52 and the width W1 of the wall of the metal frame 20 are set to be the same, Figure 4At the boundary portion (step) between the lower block 51 and the upper block 52 shown in A in FIG, stress is concentrated at both ends of the X-axis direction inside the space of the metal frame 20. This can also be confirmed by the actual occurrence of cracks. The boundary portion between the lower block 51 and the upper block 52 is where different components are combined (but the materials of the components are basically the same), and the central portion corresponds to where the two components are combined with the wiring pattern 53 placed therebetween. Therefore, it is believed that cracks are easily generated at the boundary portion because stress is concentrated in the mechanically weaker place.

[0040] In addition, as a cause of stress concentration, although the thermal expansion coefficient of alumina as the main material of the feedthrough 50 is about 7.2×10 -6 / °C, but the thermal expansion coefficient of the Kovar alloy of the metal frame 20 surrounding the feedthrough 50 is about 4.8×10 -6 / ℃, and the thermal expansion coefficient of Cu of the metal matrix is ​​about 16.7×10 -6 / °C. The upper block 52 of the feed-through 50 is fixed only to the metal frame 20, but the lower block 51 is fixed to the metal base 10 in addition to being fixed to the metal frame 20. Therefore, it is considered that due to the difference in stress applied to the lower block 51 and the upper block 52 caused by thermal expansion and contraction, in the boundary portion between the lower block 51 and the upper block 52, the stress is concentrated on the portion close to the metal frame 20.

[0041] On the other hand, in the present embodiment, the upper block 52 of the feedthrough 50 is configured to protrude from the metal frame 20 at least into the space on the inner side of the metal frame 20, so that the boundary portion between the lower block 51 and the upper block 52 is allowed to be located away from the metal frame 20, and a side plate made of metal and covering the entire side surface of the feedthrough 50 is provided between the metal frame 20 and the cutout 21 of the metal frame 20, thereby reducing the difference in stress applied to the lower block 51 and the upper block 52. Therefore, it is possible to prevent cracks from being generated at the boundary portion.

[0042] [Second embodiment]

[0043] Figure 5is a stereoscopic view showing a feedthrough member combined with a side plate in a semiconductor device according to a second embodiment. Compared with the first embodiment, in the second embodiment, each of the side plates 60' integrally has a reinforcing portion 61 shown in dotted lines. The reinforcing portion 61 is different in that the reinforcing portion has a triangular shape that fills the step of the side plate 60 of the first embodiment. Then, although the reinforcing portion 61 is at least provided on the inner space side of the metal frame 20 of the feedthrough member 50, the reinforcing portion can also be provided on the outer side of the metal frame 20. Because the side plate 60' has the reinforcing portion 61, the difference in stress applied to the upper block 52 made of ceramic and the lower block 51 made of ceramic of the feedthrough member 50 is further reduced by the reinforcing portion 61, so that cracks generated at the combined portion due to stress can be further suppressed.

[0044] [Third embodiment]

[0045] Figure 6 is a perspective view showing a feedthrough member combined with a side plate in a semiconductor device according to a third embodiment. The third embodiment is different from the second embodiment in that the feedthrough member 50 has a triangular prism-shaped reinforcement portion 54 that fills the step on the inner space side of the metal frame 20. The triangular prism-shaped reinforcement portion 54 is made of ceramic like the lower block 51 and the upper block 52, and the lower block 51, the upper block 52 and the reinforcement portion 54 are integrally formed. Therefore, since the boundary portion between the upper block made of ceramic and the lower block made of ceramic of the feedthrough member 50 is integrally covered and reinforced by the triangular reinforcement portion 54, the influence of stress applied to both can be further reduced compared to the second embodiment.

Claims

1. A semiconductor device, the semiconductor device include: Metal substrate; a metal frame, the metal frame being placed on the metal substrate and the metal frame being provided with at least one cutout penetrating the metal frame; a semiconductor element mounted on the metal base in a space defined by the metal base and the metal frame; A feed-through, the feed-through being inserted into the cut-out of the metal frame and being mounted on the metal substrate, the feed-through comprising: a wiring configured to electrically connect the semiconductor element located inside the space to an electrical component located outside the semiconductor device; a lower block made of ceramic and on which the wiring is mounted; and an upper block made of ceramic and mounted on the lower block, wherein a combined cross-sectional shape of the lower block and the upper block is a protruding shape along a mounting direction in which the upper block is mounted on the lower block, and the upper block protrudes from the metal frame toward the space so that a portion of the upper block is located inside the frame, and A metal side plate, which is fixed to the side surface of the feed-through by a brazing material and covers the entire side surface of the feed-through, and is arranged between the side surface of the feed-through and the metal frame to expand along the extension direction of the wiring, and the metal side plate has a protruding shape.

2. The semiconductor device according to claim 1, in, The metal side plates are made of copper.

3. The semiconductor device according to claim 1 or 2, in, The metal side plate further includes a triangular reinforcement portion filling a first step of the side plate, wherein the first step is located inside the space.

4. The semiconductor device according to claim 3, in, The feedthrough further includes a triangular prism-shaped reinforcement portion filling a second step of the feedthrough, wherein the second step is located inside the space.

5. The semiconductor device according to claim 1 or 2, in, The metal side plate has a thickness of at least 300 μm.

6. The semiconductor device according to claim 1 or 2, further comprising at least one circuit located inside the metal frame, in, The wiring of the feedthrough is configured to electrically connect the semiconductor element to the electrical component via the at least one circuit. 7 . The semiconductor device according to claim 1 , further comprising another feedthrough inserted into another cutout of the metal frame and mounted on the metal base.

8. The semiconductor device according to claim 7, in, The other feedthrough comprises: another wiring configured to electrically connect the semiconductor element to another electrical component located outside the semiconductor device; another lower block, the another lower block being made of ceramic and the another wiring being mounted on the another lower block; and another upper block, the other upper block being made of ceramic and being mounted on the other lower block, Wherein, along the installation direction of installing the other upper block on the other lower block, the combined cross-sectional shape of the other lower block and the other upper block is a protruding shape, and a part of the other upper block is located inside the metal frame.

9. The semiconductor device according to claim 7, in, The feedthrough, the semiconductor element and the further feedthrough are arranged along a straight line. 10 . The semiconductor device according to claim 1 , further comprising another side plate covering the entire opposite side surface of the feed-through.

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