JP5387133B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device, and more particularly to a semiconductor device including a waveguide connection.

  With the recent development of technology, the use of electromagnetic waves in the millimeter wave band is spreading, such as high-speed signal transmission exceeding 1 Gbps and automotive radar applications. When transmitting electromagnetic waves with a high frequency such as millimeter wave band through a planar line such as a microstrip line or a coplanar line, because the frequency is high, dielectric loss occurs in the dielectric in the line, and attenuation of the transmitted electromagnetic wave, that is, transmission Loss will increase. Therefore, a waveguide having better transmission efficiency than a planar line is often used mainly as a transmission line.

  However, in many cases, the input / output portion of a millimeter-wave semiconductor used for a communication device or the like is via a coplanar line, which is a kind of a planar line, and as shown in Patent Document 1 and Patent Document 2, When an electromagnetic wave is transmitted between the waveguides, a connection structure (converter) is required between them. The connection structure shown in FIG. 1 of Patent Document 1 and FIGS. 1 and 6 of Patent Document 2 is a coplanar line or a microstrip line disposed on a substrate provided separately from the semiconductor substrate. The electromagnetic wave transmitted through the planar line is radiated into the waveguide using a slot or probe formed in the planar line as a radiation source, and the electromagnetic wave is propagated into the waveguide.

JP 2006-303853 A JP 2004-032321 A JP 2008-283181 A

  However, the configurations disclosed in Patent Document 1 and Patent Document 2 have several problems.

  The first problem is the use of a planar line with poor transmission efficiency as described above. That is, the connection structure shown in FIG. 1 of Patent Document 1 and FIG. 1 of Patent Document 2 is configured to propagate electromagnetic waves by directly contacting a planar line such as a coplanar line or a microstrip line with a waveguide. Yes, it is premised on using a plane line with a large transmission loss. Moreover, although the connection structure shown by FIG. 6 of patent document 2 does not make a plane line and a waveguide contact directly, the electromagnetic waves from a semiconductor substrate cannot be directly transmitted to a waveguide, It is also assumed that a planar line is used between the semiconductor substrate and the waveguide.

  As described above, the transmission loss of the planar line is larger than that of the waveguide. For example, the transmission loss of a WR-28 waveguide is about 0.005 dB / cm at 40 GHz, whereas the loss of a microstrip line on an alumina substrate is 1 dB / cm. Further, the loss of the microstrip line on the resin substrate is equal to or more than that of the microstrip line on the alumina substrate.

  Nowadays, it is possible to create a microwave / millimeter wave transceiver with a single-chip semiconductor, and in this case, a wiring board for combining the semiconductors is not necessary. The advantage of a single chip is that it can reduce the number of wiring boards with large transmission loss, but for the reasons described above, a board with a planar line for transmitting electromagnetic waves from a semiconductor substrate to a waveguide is completely used. I can't lose it. As a result, even if the semiconductor is made into one chip, a large transmission loss occurs in the planar line.

  The second problem is that the electromagnetic wave propagates through the space surrounded by the metal inner wall surface in the waveguide. Therefore, if the wall surface is not continuous, the electromagnetic wave leaks out from the gap and transmission loss is reduced. As a result, when a planar line and a waveguide are joined, it is necessary to join both without gaps. As a result, the ground of a planar line such as a coplanar line or a microstrip line must be directly connected to the waveguide, and the connection structure between the planar line and the waveguide becomes complicated.

  Further, when a semiconductor substrate is packaged with ceramic or resin, in order to join the waveguide and the semiconductor substrate without leakage of electromagnetic waves, a planar line provided between the semiconductor substrate and the waveguide is connected from the semiconductor substrate. Since it is necessary to form a ground conductor that penetrates the package and to connect the waveguide and the semiconductor substrate through the ground conductor, the semiconductor package becomes complicated.

  The object of the present invention is the above-described problem. When connecting a semiconductor substrate and a waveguide, a connection structure using a planar line is required, and the structure of the semiconductor package becomes complicated. It is to provide a semiconductor device that solves the problem.

In the semiconductor device of the present invention, at least a radiation element that radiates or receives electromagnetic waves is provided on a semiconductor substrate. At least the semiconductor substrate and the radiating element are covered with a dielectric to form a package. Furthermore, the surface of the package is connected to a hollow waveguide having an opening, and the waveguide is located on the surface of the semiconductor substrate on which the radiation element is provided , and reflects electromagnetic waves. A reflective element is disposed on the semiconductor substrate around the radiating element with a distance from at least a part of the radiating element, and at least a part of the reflective element is opposed to the opening of the waveguide .

  According to the present invention, electromagnetic waves can be directly transmitted between the radiating element provided on the semiconductor substrate and the waveguide, so that the electromagnetic waves can be transmitted with high efficiency. Further, the structure of the package covering the semiconductor substrate is not complicated.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of one Embodiment of the semiconductor device based on this invention, (a) is a schematic diagram of an upper surface, (b) is a schematic diagram of the AA 'cross section of (a). It is the cross-sectional schematic which shows other embodiment of the semiconductor device which concerns on this invention. It is the cross-sectional schematic which shows other embodiment of the semiconductor device which concerns on this invention. FIG. 2 is a schematic cross-sectional view when a conductor layer is provided in the semiconductor device shown in FIG. 1.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same number is attached | subjected to the structure which has the same function in an accompanying drawing, and the description may be abbreviate | omitted.

  1A and 1B are schematic views of an example of an embodiment of a semiconductor device according to the present invention. FIG. 1A is a schematic view of a top surface, and FIG. 1B is a schematic view of an AA ′ cross section of FIG. In FIG. 1 (a), the package is actually covered except for the waveguide. However, the package is omitted in order to understand the details of this embodiment.

  On a semiconductor substrate 10 formed of silicon (Si), gallium arsenide (GaAs), or the like, an active element portion 11 having a function of transmitting and receiving electromagnetic waves such as microwaves and millimeter waves is provided. Further, on the semiconductor substrate 10, the signal wiring 21 drawn from the active element portion 11 and the signal wiring 21 are connected, and the electromagnetic wave is radiated and / or the radiating element 22 that receives the electromagnetic wave, and the electromagnetic wave is reflected. A plurality of reflective elements 23 are provided.

  The signal wiring 21, the radiating element 22, and the reflecting element 23 are part of a metal wiring layer formed on the semiconductor substrate 10.

  The plurality of reflecting elements 23 that reflect electromagnetic waves are arranged on the semiconductor substrate 10 so as to surround the radiating element 22 at positions not directly connected to the signal wiring 21 and the radiating element 22. The semiconductor substrate 10, the active element portion 11, the signal wiring 21, the radiating element 22, and the reflecting element 23 are all covered with a package 30 made of a dielectric material. A waveguide 50 is connected to the surface of the package 30 so that the center of the waveguide opening 51 is located immediately above the radiation element 22. By doing in this way, electromagnetic waves are transmitted between the radiation element 22 and the waveguide opening 51 with high efficiency. Note that the position of the waveguide 50 is not limited to this position as long as it can transmit electromagnetic waves.

  Next, the semiconductor device of the present invention will be described in more detail.

  An active element portion 11 is formed on the surface of the semiconductor substrate 10. An example of the active element unit 11 is capable of generating microwave or millimeter wave electromagnetic waves. Generally, silicon (Si), gallium arsenide (GaAs), or the like is widely used. If possible, it need not be limited to silicon or gallium arsenide. However, the active element unit 11 is not limited to a transmitter that generates electromagnetic waves, but a receiver having a function of receiving and processing incident electromagnetic waves, a transmitter / receiver that transmits and receives electromagnetic waves, or a single transistor such as a transistor. You may comprise only a functional element. Hereinafter, an example in which the active element unit 11 is a transmitter will be described.

ただし、ｆ：共振周波数、ｃ：光速、Ｌ：正方形パッチの一辺の長さ、ε：比誘電率 The electromagnetic wave generated in the active element unit 11 is transmitted to the radiating element 22 through the signal wiring 21. The signal wiring 21 and the radiating element 22 are part of a metal wiring layer formed on the semiconductor substrate 10. The signal wiring 21 and the radiating element 22 are optimally formed from a material having a small conductor loss such as gold (Au) or copper (Cu) in order to transmit electromagnetic waves, but are formed from other metal materials. However, this does not hinder the effects of the present invention. The radiating element 22 is optimally a patch antenna structure capable of efficiently radiating electromagnetic waves with only one metal wiring layer. It is known that the size of a patch antenna with good radiation efficiency is a square shape that satisfies Equation 1, for example. Of course, the structure of the radiating element 22 is not limited to this structure, and there is no problem as long as the structure can radiate electromagnetic waves.
[Formula 1]

Where f: resonance frequency, c: speed of light, L: length of one side of square patch, ε: relative dielectric constant

  The object of the present invention is to transmit the electromagnetic wave generated in the active element unit 11 to the waveguide 50, and all the electromagnetic waves radiated from the radiation element 22 to the space are transmitted to the waveguide 50. Is desirable. Therefore, by disposing a plurality of reflecting elements 23 around the radiating element 22, side radiation from the radiating element is suppressed.

  The reflective element 23 is optimally an electromagnetic bandgap structure (EBG structure) that can be formed by patterning a metal wiring layer. For example, as exemplified in Patent Document 3, the EBG structure includes a periodic structure in which a metal patch 23a in which a metal wiring layer is formed in a square shape or the like is periodically provided, and a short-circuit pin 23b for connecting the metal patch 23a to the ground. Therefore, it can be formed with a through hole communicating between the semiconductor substrate 10 and the metal patch, and can be easily formed on the semiconductor substrate 10 (see Patent Document 3). In addition, since the EBG structure can be formed by a normal semiconductor formation process, it is not necessary to introduce a new manufacturing apparatus or the like, and no special additional manufacturing cost due to capital investment or the like is required. On the other hand, since the EBG structure can reflect electromagnetic waves satisfactorily, electromagnetic waves can be prevented from leaking to the side of the radiation element 22. Needless to say, the reflecting element 23 is not limited to the EBG structure, and any other structure can be used as long as the electromagnetic wave radiated from the radiating element 22 can be reflected.

  The semiconductor substrate 10 is often disposed on and connected to a lead frame made of metal (not shown in FIGS. 1 and 2) for forming input / output electrodes. For this reason, since the electromagnetic wave radiated downward from the radiating element 22 is reflected by the lead frame, the electromagnetic wave from the radiating element 22 is radiated upward and laterally of the semiconductor substrate 10. Therefore, the electromagnetic wave radiated from the radiating element 22 can be efficiently transmitted to the waveguide 50.

  In addition, when the active element part 11 has the function of a receiver for electromagnetic waves, the flow of electromagnetic waves is only the reverse of the above operation, and the effect is the same.

  As described above, the electromagnetic wave radiated from the radiating element 22 is efficiently radiated and transmitted only to the waveguide 50. That is, in the present embodiment, the electromagnetic wave is not transmitted by direct contact between the semiconductor substrate 10 or the planar line connected to the semiconductor substrate 10 and the waveguide 50 as in the related art, but connected to the semiconductor substrate 10. The electromagnetic wave radiated from the radiating element 22 is transmitted through the space between the radiating element 22 and the waveguide 50. Therefore, unlike the related art, it is not necessary to directly join the waveguide 50 and the ground of the planar line, and it is not necessary to add an additional wiring board provided with the planar line to the semiconductor substrate 10. Therefore, no connection structure (converter) is required. Therefore, electromagnetic waves can be transmitted from the semiconductor substrate 10 to the waveguide 50 with high efficiency. Further, the structure of the package covering the semiconductor substrate 10 is not complicated.

  The package 30 is generally formed by an epoxy resin transfer molding method, but it goes without saying that there is no problem even if it is made of another resin material, a material other than resin, or another package structure.

  1 and 2, the reflective elements 23 are arranged in one row with respect to one direction, but may be arranged in two rows with respect to one direction, or arranged so as to form more rows. There is no problem.

  The above description exemplifies the case where the active element unit 11 is a transmitter. However, when the active element unit 11 is a receiver, the electromagnetic wave transmitted through the waveguide 50 is transmitted to the radiating element 22. To the receiver (active element unit 11), and can be processed by the receiver. When the active element unit 11 is a transceiver, both radiation and reception of electromagnetic waves may be performed by the radiation element 22. And the radiation element 22 of this invention may have not only what has the function to radiate | emit electromagnetic waves like the above-mentioned example but also the function to receive electromagnetic waves.

  Another embodiment of the semiconductor device of the present invention will be described.

  FIG. 2 is a schematic cross-sectional view showing another embodiment of the semiconductor device of the present invention. In addition, description is abbreviate | omitted about the same thing as said embodiment.

  In the present embodiment, a structure in which a part of the package 30 is positioned by being inscribed in the waveguide 50 facilitates the alignment of the radiating element 22 and the waveguide 50. The emitted electromagnetic wave can be radiated to the waveguide 50 more efficiently.

  Specifically, a convex guide 30a that is a convex protrusion is provided at a position where the waveguide 50 of the package 30 is installed. The convex guide 30 a is shaped so as to be inscribed in the waveguide 50, and is directly above the radiating element 22. Further, the convex guide 30a and the radiating element 22 are arranged so that the centers thereof coincide. Thereby, when the waveguide 50 is connected to the package 30, the waveguide 50 can be easily aligned at the optimum position, that is, the center of the waveguide opening 51 and the center of the radiating element 22.

  The height of the convex guide 30a is not limited as long as the waveguide 50 can be aligned. However, since the package 30 is made of a dielectric material, if the height of the convex guide 30a is high, the waveguide is guided. The inside of the tube is filled with a dielectric, and dielectric loss may occur or the propagation mode may not become a desired mode. For this reason, the height of the convex guide 30a is desirably equal to or less than ¼ wavelength of the wavelength of the propagating electromagnetic wave.

  Still another embodiment of the semiconductor device of the present invention will be described.

  FIG. 3 is a schematic sectional view showing still another embodiment of the semiconductor device of the present invention. In addition, description is abbreviate | omitted about the same thing as said embodiment.

  By disposing a patterned metal layer or the like on the surface of the package 30 of the second embodiment, electromagnetic waves can be radiated from the radiating element 22 to the waveguide 50 more efficiently.

  A metal pattern 40 is provided on the surface of the convex guide 30a and immediately above the radiation element 22 by vacuum deposition or sputtering. By doing so, the metal pattern 40 functions like a director, and the radiating element 22 and the metal pattern 40 can be strongly electromagnetically coupled. The emitted electromagnetic wave is transmitted to the metal pattern 40. Then, electromagnetic waves are emitted again from the metal pattern 40 into the waveguide 50. Since the metal pattern 40 is on the surface of the convex guide 30a, it exists inside the waveguide 50, and electromagnetic waves are radiated from the metal pattern 40 inside the waveguide to the waveguide 50. Therefore, the metal pattern 40 is guided very efficiently. Electromagnetic waves can be transmitted to the tube 50.

  The shape of the metal pattern 40 is optimally the same as the shape of the radiating element 22, but is not limited to the same shape, and there is no problem as long as the shape is impedance-matched with the radiating element 22 and can be electromagnetically strongly coupled. Needless to say. The thickness of the metal pattern 40 is preferably equal to or greater than the skin depth of the electromagnetic wave transmitted through the waveguide 50. However, even the thickness equal to or less than the skin depth does not hinder the effect of the present invention. Furthermore, the metal material of the metal pattern 40 is optimally a metal with a small conductor loss, such as gold or copper, but it goes without saying that other metals are not a problem.

  Further, as shown in FIG. 4, even when the convex guide 30a is not provided on the package 30 as in the first embodiment, the metal pattern 40 as the conductor layer is formed on the flat surface of the package 30, and By providing in the opening part 51 of the waveguide 50, the effect similar to said embodiment is acquired.

  Examples of the use of the semiconductor device of the present invention include, but are not limited to, a large-capacity digital signal transmission device, a radar device, and a communication device using millimeter waves.

DESCRIPTION OF SYMBOLS 10 Semiconductor substrate 11 Active element part 21 Signal wiring 22 Radiation element 23 Reflective element 23a Metal patch 23b Short-circuit pin 30 Package 30a Convex guide 40 Metal pattern 50 Waveguide 51 Waveguide opening

Claims (22)

At least a radiation element that emits or receives electromagnetic waves is provided on a semiconductor substrate, and a package is formed by covering at least the semiconductor substrate and the radiation element with a dielectric, and has a surface of the package and an opening. A semiconductor device connected to a hollow waveguide;
The waveguide is located on a surface of the semiconductor substrate on which the radiation element is provided;
A reflective element that reflects the electromagnetic wave is disposed on the semiconductor substrate around the radiating element with an interval from at least a portion of the radiating element,
A semiconductor device, wherein at least a part of the reflective element and the opening of the waveguide face each other.   The semiconductor device according to claim 1, wherein the reflective element is disposed at a position facing the outer periphery of the opening.   The semiconductor device according to claim 2, wherein the reflection element is disposed so as to surround the periphery of the radiation element.   The semiconductor device according to claim 1, wherein at least a part of the radiating element and the opening of the waveguide face each other.   5. The semiconductor device according to claim 1, wherein the center of the opening of the waveguide and the position of the radiating element are the same in the horizontal direction.   The semiconductor device according to claim 1, wherein the reflective element has an electromagnetic band gap structure.   The semiconductor device according to claim 1, wherein a conductor layer is provided on a surface of the package and inside the opening of the waveguide.   8. The package according to claim 1, wherein the package has a protrusion having a convex shape inscribed in the opening of the waveguide at a position to which an end of the waveguide is connected. 9. Semiconductor device.   The semiconductor device according to claim 8, wherein the reflective element is located at a position facing the outer periphery of the protrusion.   10. The semiconductor device according to claim 8, wherein a height of the projecting protrusion is λ / 4 or less, where λ is a wavelength of the electromagnetic wave. 11.   11. The semiconductor device according to claim 8, wherein a conductor layer is provided on a tip surface of the projecting portion having the convex shape.   12. The semiconductor device according to claim 7, wherein the conductor layer has a shape capable of impedance matching with the radiating element and strong coupling. At least a radiating element that radiates electromagnetic waves is provided on a semiconductor substrate, and at least the semiconductor and the radiating element are covered with a dielectric to form a package, and the electromagnetic wave radiated by the radiating element is transmitted to the surface of the package. An electromagnetic wave transmission method for a semiconductor device to which a hollow waveguide having an opening is connected,
The waveguide is disposed on a surface of the package on which the radiation element of the semiconductor substrate is provided;
A reflective element that reflects the electromagnetic wave is disposed on the semiconductor substrate around the radiating element at a distance from at least a portion of the radiating element,
An electromagnetic wave transmission method, wherein an electromagnetic wave from the radiating element is transmitted to the waveguide, and the electromagnetic wave traveling toward the reflective element is reflected by the reflective element. On the semiconductor substrate, at least a radiating element that receives electromagnetic waves is provided, and at least the semiconductor substrate and the radiating element are covered with a dielectric to form a package, and an opening that transmits the electromagnetic waves to the radiating element on the surface of the package An electromagnetic wave transmission method of a semiconductor device to which a hollow waveguide having a portion is connected,
The waveguide is disposed on a surface of the package on which the radiation element of the semiconductor substrate is provided;
A reflective element that reflects the electromagnetic wave is disposed on the semiconductor substrate around the radiating element at a distance from at least a portion of the radiating element,
An electromagnetic wave transmission method, wherein an electromagnetic wave from the opening of the waveguide is transmitted to the radiating element, and the electromagnetic wave traveling toward the reflective element is reflected by the reflective element.   The electromagnetic wave transmission method according to claim 13 or 14, wherein the reflective element is disposed at a position facing an outer periphery of the opening.   The electromagnetic wave transmission method according to claim 15, wherein the reflection element is arranged so as to surround the periphery of the radiation element. At least a portion is opposed to the said opening of the waveguide, the electromagnetic wave transmission method according to any one of claims 1 3 to 16 of the radiating element. Arranging the position of the center and the radiating element of the opening of the waveguide at the same position in the horizontal direction, the electromagnetic wave transmission method according to any one of claims 1 to 3 17. On the surface of the package, and a conductor layer provided on the inner side corresponding to the position of said opening of said waveguide, said conductive layer and the radiating element and the impedance matching, thereby strongly coupled, claim 1 to 3 18 2. The electromagnetic wave transmission method according to item 1. A protrusion provided with a convex connected to the position of the waveguide of the package, is inscribed in the opening of the waveguide by the protruding portion, according to any one of claims 1 to 3 19 Electromagnetic wave transmission method.   21. The electromagnetic wave transmission method according to claim 20, wherein the height of the projecting portion of the convex shape is set to λ / 4 or less where the wavelength of the electromagnetic wave is λ.   The electromagnetic wave transmission method according to claim 20 or 21, wherein a conductor layer is provided on a front end surface of the convex protrusion, and the radiating element and the conductor layer are impedance-matched and strongly coupled.

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