JP4810925B2 - Semiconductor package, semiconductor device and electronic device - Google Patents

Description

  The present invention includes a printed circuit board on which analog circuits and digital circuits are formed at high density, a plurality of integrated circuits (ICs) having different functions, and a large scale integrated circuit (LSI) mounted in a single package. The present invention relates to a semiconductor package such as a system in package (SIP) that functions as a semiconductor device, a semiconductor device including such a semiconductor package, and an electronic device including such a printed circuit board or semiconductor device.

  Conventionally, a power supply system of a printed circuit board or a semiconductor package generally has a dielectric layer sandwiched between a power supply layer 1, a ground layer 2, and the power supply layer 1 and the ground layer 2, as shown in FIG. 3 and a decoupling capacitor 4. In many cases, the power supply layer 1 and the ground layer 2 have a substantially planar shape so as to make the impedance as low as possible with the intention of providing a stable power supply to the IC and LSI and a signal return path. The dielectric layer 3 exists uniformly between the power supply layer 1 and the ground layer 2. Further, the decoupling capacitor 4 is not only used as an element for supplying power to an IC or LSI, but also plays a role of suppressing electromagnetic interference between different circuits or unnecessary electromagnetic radiation (EMI) (for example, Patent Documents). 1). Hereinafter, this technique is referred to as a first conventional example.

  In addition, in the conventional printed circuit board, the dielectric layer disposed between the power supply layer and the ground layer is configured by two dielectrics having different dielectric constants, so that a plane along the power supply layer and the ground layer is obtained. As a weak resonance having a distribution in the dielectric constant and widely distributed on the frequency axis as a different resonance condition for each part, there is one that reduces strong electromagnetic wave radiation generated at a specific frequency (for example, Patent Document 2). reference.). Hereinafter, this technique is referred to as a second conventional example.

  In addition, a conventional printed circuit board is configured such that a power supply layer formed on one surface side of one substrate and a ground layer formed on one surface side of another substrate face each other across a dielectric layer. In some cases, a notch is formed in the dielectric layer at the peripheral end, and the notch is filled with air as the end dielectric layer (see, for example, Patent Document 3). Hereinafter, this technique is referred to as a third conventional example.

JP 2002-290050 A ([0003]) Japanese Patent Laid-Open No. 11-40905 ([0017], [0019] to [0033], FIG. 1, FIG. 2, FIG. 6) JP-A-7-235770 ([0007], [0008], [0014] to [0019], FIG. 1)

  However, the first conventional example described above has a problem that electromagnetic interference and EMI between different circuits cannot be sufficiently suppressed when the frequency is in the gigahertz (GHz) band. Hereinafter, the generation process of these electromagnetic wave problems will be briefly described with reference to FIG. FIG. 9 is a schematic diagram of one mounting form in a recent high-density mounting printed circuit board and semiconductor package. The power supply system for the printed circuit board and the semiconductor package includes a power supply layer 11, a ground layer 12, a dielectric layer 13 sandwiched between the power supply layer 11 and the ground layer 12, and a decoupling capacitor 14. A digital circuit 15 and a radio frequency (RF) circuit 16 are mounted together.

  With the switching operation of the digital circuit 15, an excessive current I flows as shown in FIG. 9, and this current I becomes a wave source to generate an electromagnetic wave EMW in the power supply system. The electromagnetic wave EMW generated in this way travels from the digital circuit 15 to the RF circuit 16 and is mixed into the RF circuit 16 as noise, resulting in malfunction of the RF circuit 16 or lower performance. The electromagnetic wave EMW is repeatedly reflected at the end of the printed circuit board or semiconductor package, and becomes a standing wave in a steady state. The standing wave in such a power supply system loses its energy due to electromagnetic radiation from the edge of the printed circuit board or semiconductor package. That is, this is a factor in the generation of EMI. As a result, a lot of time and cost are required for EMI countermeasures in a semiconductor device including such a semiconductor package and an electronic apparatus including such a printed circuit board or semiconductor device.

As a countermeasure technique for these electromagnetic wave problems in a conventional printed circuit board or semiconductor package, as shown in FIG. 9, a decoupling capacitor 14 is arranged in the vicinity of each of the digital circuit 15 and the RF circuit 16 to A technique for enhancing the isolation between the RF circuit 16 and the RF circuit 16 is typical. That is, there is a technique for suppressing electromagnetic interference and EMI between different circuits as much as possible by suppressing leakage of electromagnetic energy from the digital circuit 15 and the RF circuit 16 to a minimum by appropriately selecting and arranging the decoupling capacitor 14. Commonly used.
However, when the decoupling capacitor 14 is mounted, circuit isolation in the GHz band cannot be realized due to the influence of the parasitic inductance or equivalent series inductance associated therewith. Problems have become apparent, and the establishment of countermeasure technology for this has become an issue.

In this regard, according to the above-described second conventional example, the resonance frequency is diffused by providing a distribution in the dielectric constant of the dielectric layer, and strong electromagnetic radiation at a specific resonance frequency generated in the case of a single dielectric constant. However, there is a problem that electromagnetic interference between different circuits and EMI due to electromagnetic coupling in the GHz band cannot be suppressed.
On the other hand, according to the above-described third conventional example, electromagnetic radiation can be reduced by attenuating electromagnetic waves with a different dielectric provided at the peripheral end of the dielectric layer. There was a problem that inter-electromagnetic interference and EMI could not be suppressed.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a printed circuit board, a semiconductor package, a semiconductor device, and an electronic apparatus that can solve the above-described problems.

In order to solve the above problems, a semiconductor package according to the invention of claim 1 is a semiconductor package having a configuration in which a digital circuit and a radio frequency circuit are mounted on one main surface of a printed circuit board, The printed circuit board includes a power supply layer and a ground layer made of planar conductors, and a dielectric layer provided between the power supply layer and the ground layer. The dielectric layer is a first dielectric layer. In the dielectric layer, a patch made of a second dielectric material having a relative dielectric constant different from that of the first dielectric material has a constant spacing between adjacent lattices in plan view. It is characterized by being periodically arranged in a lattice pattern.

According to a second aspect of the invention, there is provided the semiconductor package according to the first aspect, wherein a difference in relative dielectric constant between the first dielectric material and the second dielectric material is 8 or more.
The invention according to claim 3 relates to the semiconductor package according to claim 1 or 2, wherein the first dielectric material and the second dielectric material are fluororesin, air, aluminum oxide, barium titanate. , Lithium niobate, or lithium tantalate.

According to a fourth aspect of the present invention, a semiconductor device includes the semiconductor package according to any one of the first to third aspects.
According to a fifth aspect of the present invention, an electronic apparatus includes the semiconductor device according to the fourth aspect.

  ADVANTAGE OF THE INVENTION According to this invention, the electromagnetic interference and EMI between different circuits by the electromagnetic coupling in GHz band in the power supply system of a printed circuit board or a semiconductor package can be suppressed. As a result, it is possible to prevent malfunctions and lower performance of circuits mounted on a printed circuit board, ICs and LSIs mounted in a semiconductor package, particularly RF circuits. As a result, it is possible to reduce the time and cost required for EMI countermeasures in a semiconductor device including such a semiconductor package and an electronic device including such a printed circuit board or semiconductor device.

Hereinafter, embodiments of the present invention will be described specifically and in detail with reference to the drawings.
Embodiment 1 FIG.
1 is a perspective view showing a schematic configuration of a two-layer printed circuit board according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of the two-layer printed circuit board shown in FIG. The two-layer printed circuit board of this example has a power supply layer 21, a ground layer 22, and a dielectric layer 23 as a power supply system. This two-layer printed circuit board has, for example, a length and width of 15 cm and a thickness of 1.6 mm.

Each of the power supply layer 21 and the ground layer 22 is a planar conductor, and a dielectric layer 23 is bonded using an adhesive resin 26. The dielectric layer 23 is periodically drilled between the base materials 24 (for example, at intervals of about 2 cm) by, for example, mechanically cutting through holes having a rectangular parallelepiped shape having about 1 cm in both length and width. After being installed, the patch 25 is formed by embedding a rectangular parallelepiped patch 25 having about 1 cm in both length and width in each of the drilled through holes. The difference between the relative permittivity of the base material 24 and the relative permittivity of the patch 25 is desirably 8 or more. The base material 24 is made of, for example, a fluororesin, and the patch 25 is made of, for example, aluminum oxide (alumina) (Al ₂ O ₃ ). Examples of the fluororesin include polytetrafluoroethylene (Teflon (registered trademark)) composed of only fluorine atoms and carbon atoms.

  FIG. 3 shows the result of measuring the S21 amplitude component using a network analyzer after attaching an SMA (Sub Miniature Type A) type connector to the approximate center of each of the two sides of the opposing printed circuit board. Here, the SMA connector is one type of coaxial connector and is the connector most commonly used in the microwave band. The S21 amplitude component is one of S parameters (S-parameters) in a 2-port (4-terminal) circuit, and is called a voltage transmission coefficient. The measurement band is 0 to 10 GHz.

  In FIG. 3, a region indicated by an arrow is a band gap band BG of electromagnetic wave energy. In this band gap band BG, an electromagnetic wave traveling from a digital circuit to an RF circuit (hereinafter referred to as “traveling electromagnetic wave”). It cannot be present. That is, according to the first embodiment of the present invention, by configuring the dielectric layer 23 constituting the power supply system of the two-layer printed circuit board as shown in FIGS. 1 and 2, in the band gap band BG, Electromagnetic interference and EMI between different circuits due to electromagnetic coupling as shown in FIG. 9 are suppressed.

  The reason will be described below. The dielectric layer 23 composed of the base material 24 and the patch 25 having different relative dielectric constants can be regarded as equivalent to an artificial two-dimensional crystal. However, the difference is that the dielectric layer 23 is composed of a periodic array of patches 25 while the crystal is composed of a periodic array of atoms. In the case of crystals, an energy band in which no traveling electron wave can exist is formed, which is called a “band gap”, but in this band the electron wave can only take a reflection state called Bragg reflection. It is understood.

  Since the phenomenon of black reflection similarly occurs in electromagnetic waves, in the present invention, the dielectric layer 23 constituting the power supply system of the two-layer printed circuit board is configured as shown in FIGS. Thus, Bragg reflection of electromagnetic waves, that is, a state in which traveling electromagnetic waves cannot exist in a certain frequency band of electromagnetic waves and an incident wave is almost reflected is intentionally realized. Therefore, in the band gap band BG, for example, the electromagnetic wave generated in the power supply system by the switching operation of the digital circuit mounted on the two-layer printed circuit board is almost reflected in the vicinity of the generation point. A certain RF circuit or power supply system end cannot be reached. As a result, it is understood that electromagnetic interference and EMI between different circuits are suppressed. The reason described above is also the case where the patch 25 is not embedded in the through-holes periodically drilled between the base materials 24 (Embodiment 3 described later), that is, when air is used as the dielectric. The same applies. As a result, it is possible to prevent malfunctions and low performance of circuits mounted on a printed circuit board, particularly RF circuits. As a result, it is possible to reduce the time and cost required for EMI countermeasures in an electronic device equipped with such a printed circuit board.

Embodiment 2. FIG.
In the first embodiment described above, the dielectric layer 23 is periodically drilled between the base materials 24, for example, through holes having a rectangular parallelepiped shape having about 1 cm in both length and width by mechanical cutting. Then, although the example comprised by embedding the patch 25 which exhibited the rectangular parallelepiped shape which has 1 cm in both length and width in each through-hole drilled was shown, this invention is not limited to this. For example, the patch 25 may have a columnar shape or a polygonal column shape such as a triangular prism shape, and a through hole formed in the base material 24 for embedding the patch 25 may also have a shape corresponding to the patch 25.

Embodiment 3 FIG.
In Embodiment 1 and 2 mentioned above, although the base material showed the example which consists of a fluororesin, this invention is not limited to this. For example, the base material may be air having a relative dielectric constant of 1. In this case, the relative dielectric constant of the patch is desirably 9 or more. Even in such a configuration, a band gap band BG is formed in the GHz band, and similarly to the first and second embodiments described above, in the band gap band BG, electromagnetic interference between different circuits due to electromagnetic coupling and EMI are suppressed. . As a result, it is possible to prevent malfunctions and low performance of circuits mounted on a printed circuit board, particularly RF circuits. However, the position and band of the band gap band BG are different from those in the first and second embodiments. For this reason, the designer must select whether the base material of the dielectric layer is made of fluororesin or air while considering the frequency band in which electromagnetic interference between different circuits due to electromagnetic coupling and suppression of EMI are desired. Can do. As a result, it is possible to reduce the time and cost required for EMI countermeasures in an electronic device equipped with such a printed circuit board.

Embodiment 4 FIG.
In the first to third embodiments described above, the dielectric layer is a combination of a fluororesin and aluminum oxide (alumina) (Al ₂ O ₃ ) or a combination of air and aluminum oxide (alumina) (Al ₂ O ₃ ). Although the example comprised by is shown, this invention is not limited to this. For example, the dielectric material used as the patch may be aluminum oxide (alumina) (Al ₂ O ₃ ), barium titanate (BaTiO ₃ ), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), or the like. A dielectric material having a high relative dielectric constant may be used. In this case, the shape, size, or interval of the dielectric material used as the patch is not limited to that shown in the first embodiment.

  Since the position and band of the band gap band BG are determined based on the difference in relative dielectric constant between the two kinds of dielectric substances in the dielectric layer and the shape, size or interval of the dielectric substance used as the patch, the designer can It is possible to select the type, combination, and configuration of dielectric materials constituting the dielectric layer while considering the frequency band in which electromagnetic interference between different circuits and EMI are desired to be suppressed.

Embodiment 5 FIG.
4 is a perspective view showing a schematic configuration of a two-layer printed circuit board according to Embodiment 5 of the present invention, and FIG. 5 is a cross-sectional view of the two-layer printed circuit board shown in FIG. The two-layer printed circuit board of this example includes a power supply layer 31, a ground layer 32, and a dielectric layer 33 as a power supply system. This two-layer printed circuit board has, for example, a length of 16 cm and a thickness of 1.6 mm in both length and width.

Each of the power supply layer 31 and the ground layer 32 is a planar conductor, and a dielectric layer 33 is bonded using an adhesive resin 34. Periodically (for example, every 2 cm), through holes 35 having a rectangular parallelepiped shape having about 1 cm both vertically and horizontally are formed by mechanical cutting. The difference between the relative dielectric constant of the dielectric layer 33 and the through hole 35, that is, the relative dielectric constant of air having a relative dielectric constant of 1 is desirably 8 or more. The dielectric layer 33 is made of, for example, aluminum oxide (alumina) (Al ₂ O ₃ ).

  FIG. 6 shows the result of measuring the S21 amplitude component using a network analyzer with SMA connectors attached to the approximate center of each of the two sides of the opposing printed circuit board. The measurement band is 0 to 10 GHz. In FIG. 6, a region indicated by an arrow is a band gap band BG of electromagnetic energy, and in this band gap band BG, a traveling electromagnetic wave cannot exist. That is, according to the fifth embodiment of the present invention, by configuring the dielectric layer 33 constituting the power supply system of the two-layer printed circuit board as shown in FIGS. 4 and 5, in the band gap band BG, Electromagnetic interference and EMI between different circuits due to electromagnetic coupling as shown in FIG. 9 are suppressed. As a result, it is possible to prevent malfunctions and low performance of circuits mounted on a printed circuit board, particularly RF circuits. As a result, it is possible to reduce the time and cost required for EMI countermeasures in an electronic device equipped with such a printed circuit board.

Embodiment 6 FIG.
In the above-described fifth embodiment, the dielectric layer 33 is periodically formed with, for example, a through hole 35 having a rectangular parallelepiped shape having about 1 cm in length and width by mechanical cutting. Although shown, the present invention is not limited to this. For example, the through hole 35 may have a polygonal column shape such as a columnar shape or a triangular column shape.

Embodiment 7 FIG.
In the fifth and sixth embodiments described above, the dielectric layer 33, an example configured by aluminum oxide _(alumina) (Al 2 _O 3), the present invention is not limited thereto. For example, the dielectric layer 33 is made of barium titanate (BaTiO ₃ ), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ) or the like, instead of aluminum oxide (alumina) (Al ₂ O ₃ ). A dielectric material having a relative dielectric constant may be used. In this case, the shape, size, or interval of the through holes 35 is not limited to that shown in the fifth embodiment.

  The position and band of the band gap band BG based on the difference between the relative dielectric constant of the dielectric layer 33 and the through hole 35, that is, the relative dielectric constant of air having a relative dielectric constant of 1, the shape, size, or interval of the through hole. Therefore, the designer can select the type configuration of the dielectric material constituting the dielectric layer 33 while considering the frequency band in which electromagnetic interference between different circuits due to electromagnetic coupling and suppression of EMI are desired. .

Embodiment 8 FIG.
FIG. 7 is a perspective view showing a schematic configuration of a two-layer printed circuit board according to Embodiment 8 of the present invention. The two-layer printed circuit board of this example includes a power supply layer 41, a ground layer 42, and a dielectric layer 43 as a power supply system. This two-layer printed circuit board has, for example, a length of 16 cm and a thickness of 1.6 mm in both length and width.

Each of the power supply layer 41 and the ground layer 42 is a planar conductor, and a dielectric layer 43 is bonded using an adhesive resin (not shown). In the power supply layer 41, periodically (for example, every 1 cm), for example, through holes 44 having a square shape having about 2 cm in both length and width are formed by mechanical cutting. The dielectric layer 43 is made of, for example, aluminum oxide (alumina) (Al ₂ O ₃ ).

  Even in the configuration described above, similarly to the above-described embodiments, the band gap band BG of electromagnetic wave energy is formed in the GHz band, and in this band gap band BG, no traveling electromagnetic wave can exist. Yes. That is, according to the eighth embodiment of the present invention, the power supply layer 41 constituting the power supply system of the two-layer printed circuit board is configured as shown in FIG. Electromagnetic interference between different circuits and EMI due to such electromagnetic coupling is suppressed. As a result, it is possible to reduce the time and cost required for EMI countermeasures in an electronic device equipped with such a printed circuit board.

Embodiment 9 FIG.
In the eighth embodiment described above, the power supply layer 41 shows an example in which the through-hole 44 having a positive direction having a length of about 2 cm both vertically and horizontally is formed by mechanical cutting. However, the present invention is not limited to this. For example, the through hole 44 may have a polygonal shape such as a rectangular shape, a circular shape, or a triangular shape. Moreover, a through hole having a predetermined shape may be formed in the ground layer at a predetermined cycle without forming any through hole in the power supply layer. Further, through holes having a predetermined shape may be formed in both the power supply layer and the ground layer at a predetermined cycle. In this case, the shape and period of the through holes formed in the power supply layer and the ground layer may be the same or different.

Embodiment 10 FIG.
In the above-described eighth and ninth embodiments, the dielectric layer 43 is made of aluminum oxide (alumina) (Al ₂ O ₃ ), but the present invention is not limited to this. For example, the dielectric layer 43 is made of barium titanate (BaTiO ₃ ), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ) or the like, instead of aluminum oxide (alumina) (Al ₂ O ₃ ). A dielectric material having a relative dielectric constant may be used. On the other hand, the dielectric layer 43 may be a dielectric material such as glass epoxy resin (FR-4) having a lower relative dielectric constant than aluminum oxide (alumina) (Al ₂ O ₃ ). In this case, the shape, size, or interval of the through holes 44 is not limited to that shown in the eighth embodiment.

  Since the position and band of the band gap band BG are determined based on the type of the dielectric layer 43 and the shape, size or interval of the through hole 44, the designer can suppress electromagnetic interference between different circuits and EMI by electromagnetic coupling. The kind configuration of the dielectric material constituting the dielectric layer 33 can be selected in consideration of a desired frequency band.

The embodiment has been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiment, and there are design changes and the like without departing from the scope of the invention. Are also included in the present invention.
For example, in each of the embodiments described above, an example in which the present invention is applied to a power supply system for a two-layer printed circuit board has been described. However, the present invention is not limited to this, and the present invention is not limited to this. It can also be applied to the supply system.
In each of the above-described embodiments, an example in which the base material is fluororesin or air and the patch is aluminum oxide (alumina) (Al ₂ O ₃ ) or the like has been described. The dielectric material and the dielectric material of the patch may be exchanged.
Further, in each of the above-described embodiments, an example in which the present invention is applied to a power supply system of a printed circuit board has been shown. Can do.
In addition, each of the above-described embodiments can divert each other's technology as long as there is no particular contradiction or problem in its purpose and configuration.

1 is a perspective view showing a schematic configuration of a two-layer printed circuit board according to Embodiment 1 of the present invention. It is sectional drawing of the two-layer printed circuit board shown in FIG. It is a figure which shows the measurement result of the S21 amplitude component of the two-layer printed circuit board concerning Embodiment 1 of this invention. It is a perspective view which shows schematic structure of the two-layer printed circuit board concerning Embodiment 5 of this invention. It is sectional drawing of the two-layer printed circuit board shown in FIG. It is a figure which shows the measurement result of the S21 amplitude component of the two-layer printed circuit board concerning Embodiment 5 of this invention. It is a perspective view which shows schematic structure of the two-layer printed circuit board based on Embodiment 8 of this invention. It is a perspective view which shows schematic structure of the power supply system of the conventional printed circuit board or a semiconductor package. It is a schematic diagram of one mounting form in a recent high-density mounting printed circuit board and a semiconductor package.

Explanation of symbols

21, 31, 41 Power supply layer 22, 32, 42 Ground layer 23, 33, 43 Dielectric layer 24 Base material 25 Patch 26, 34 Adhesive resin 35, 44 Through hole

Claims (5)

A semiconductor package having a configuration in which a digital circuit and a radio frequency circuit are mounted on one main surface of a printed circuit board,
The printed circuit board includes a power supply layer and a ground layer made of a planar conductor, and a dielectric layer provided between the power supply layer and the ground layer,
The dielectric layer is made of a first dielectric material, and a patch made of a second dielectric material having a relative dielectric constant different from that of the first dielectric material is seen in a plan view in the dielectric layer. A semiconductor package characterized by being periodically arranged in a lattice shape so that the interval between adjacent lattices is constant. 2. The semiconductor package according to claim 1, wherein a difference in relative dielectric constant between the first dielectric material and the second dielectric material is 8 or more. 3. The first dielectric material and the second dielectric material are both fluororesin, air, aluminum oxide, barium titanate, lithium niobate, and lithium tantalate. The semiconductor package described in 1. A semiconductor device comprising the semiconductor package according to any one of claims 1 to 3. An electronic apparatus comprising the semiconductor device according to claim 4 .

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