This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2012-041832, filed Feb. 28, 2012, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a wireless device including a semiconductor package with a built-in antenna, and an information processing apparatus and a storage device including the wireless device.
In the field of electronic devices, in accordance with increases in frequency and circuit density and decreases in size, interference due to undesired electromagnetic radiation has become problematic, and hence there is a demand for suppression of external leakage of the undesired electromagnetic radiation. In order to impart a shielding function to a semiconductor package, there is a method for covering, with a conductive resin layer, the surface of a non-conductive resin layer that seals a semiconductor chip. Further, a technique has been proposed, in which an aperture is formed at a portion of a non-conductive resin layer for sealing the semiconductor chip, and at a portion of a conductive resin layer that covers the upper surface of the semiconductor chip, thereby realizing a module with a built-in transmission/reception antenna that has a shielding function.
However, since in this technique, the aperture is positioned just above the semiconductor chip, the distance between the semiconductor chip generating undesired electromagnetic waves and the aperture is too short, which results in degradation of a shielding effect.
Wireless devices, an information processing apparatus and a storage device provided with the wireless devices, according to embodiments, will be described in detail with reference to the accompanying drawings. In the embodiments below, like reference numerals denote like elements, and duplicate descriptions will be avoided.
The embodiments have been developed in light of the above-mentioned problem, and aim to provide a wireless device having an antenna capable of efficiently radiating or receiving electromagnetic waves, with its shielding effect enhanced, and an information processing apparatus and a storage device provided with the wireless device.
According to one embodiment, a wireless device includes a circuit board, a semiconductor chip, a sealing resin, a conductive film, and an antenna element. The semiconductor chip includes a transmitting/receiving circuit and is mounted on the circuit board. The sealing resin seals the semiconductor chip. The conductive film covers a first surface portion of the sealing resin. An aperture is formed in a portion of the conductive film that corresponds to a second surface portion of the sealing resin other than the first surface portion, and the second surface portion is included in a side surface of the sealing resin and closest to an antenna terminal connected to the antenna element.
Referring first to
The wireless device shown in
The semiconductor chip 102 is provided on a first surface of the circuit board 101, and contains a transmitting/receiving circuit for transmitting and receiving signals. The terminals 106 are provided on a second surface of the circuit board 101. The first and second surfaces are opposite to each other. Namely, if the first surface is the upper surface, the second surface is the lower surface. The semiconductor chip 102 is sealed with the sealing resin 104. The semiconductor chip 102 comprises a semiconductor substrate made of silicon, silicon germanium, gallium arsenide, etc., and having a patterned metal layer of, for example, copper, aluminum, or gold provided in the chip or a surface thereof. The semiconductor chip 102 may be formed of a dielectric substrate, a magnetic substrate, a metal substrate, or a combination thereof. The semiconductor chip 102 may also be formed of a chip size package (CSP). Although
The antenna element 103 is provided on a portion of the first surface of the circuit board 101 other than the portion of the board provided with the semiconductor chip 102. The semiconductor chip 102 and the antenna element 103 are formed with a certain space interposed therebetween. The semiconductor chip 102 and the antenna element 103 are sealed with the sealing resin 104. The antenna element 103 is connected to the antenna terminal 107 that is electrically connected to the semiconductor chip 102. The antenna terminal 107 is positioned at the tip of a transmission line electrically connected to the semiconductor chip 102 via, for example, a bonding wire or a bump. The antenna element 103 is formed of part of an antenna or of the entire antenna. The antenna element 103 may be formed on the circuit board 101 as shown in
Although greater part of the sealing resin 104 is covered with the conductive film 105, the side surface of the sealing resin 104 (semiconductor package 100) closest to the antenna terminal 107 is covered with no conductive film 105. The side surface of the sealing resin 104 covered with no conductive film 105 will hereinafter be referred to as an aperture 108. The aperture 108 is formed at a side surface of the sealing resin closest to the antenna terminal 107 connected to the antenna element 103.
To prevent the undesired electromagnetic waves generated by the semiconductor chip 102 from leaking to the outside, it is desirable to form the conductive film 105 of a metal with a low specific resistance, such as copper, silver or nickel. For instance, it is preferable to set the thickness of the conductive film 105 so that the sheet resistance obtained by dividing the specific resistance of the conductive film 105 by the thickness of the same will be 0.5Ω or less. By setting the sheet resistance of the conductive film 105 to 0.5Ω or less, leakage of undesired electromagnetic waves can be suppressed with good repeatability.
A high shielding effectiveness can be obtained if the conductive film 105 is connected to a ground terminal of the circuit board 101 with a low resistance. In
The aperture 108 is formed in the portion of the conductive film 105 that corresponds to the side surface of the sealing resin 104 closest to the antenna terminal 107, and enables radiation and reception of desired electromagnetic waves for communication. The distance between the semiconductor chip 102 and the aperture 108 can be made longer than in the case where the aperture is formed in the upper surface of the conductive film 105. Therefore, the shielding effectiveness against the undesired electromagnetic waves generated by the semiconductor chip 102 is enhanced. Thus, by forming the aperture 108 in the side surface of the conductive film 105 closest to the antenna terminal 107, transmission loss can be reduced, and degradation of antenna radiation characteristic can be suppressed.
The semiconductor package 100 shown in
In
Referring then to
In
In the above-described first embodiment, since the aperture is formed in the portion of the conductive film that corresponds to the side surface of the semiconductor package closest to the antenna terminal, degradation of the antenna radiation characteristic can be suppressed, with degradation of the shielding effectiveness against undesired electromagnetic waves suppressed.
A wireless device according to a second embodiment differs from the wireless device of the first embodiment in that in the former, an aperture is formed over a plurality of surfaces of the semiconductor package that include the side surface closest to the antenna terminal.
Referring to
By forming a continuous aperture 608 in the conductive film 105 over a plurality of surfaces of the semiconductor package 100, the main radiation direction of an antenna element 603 can be directed from the antenna element 603 to the aperture 608. Thus, the degree of freedom for setting the radiation direction is increased.
In the above-described second embodiment in which the aperture is provided above the antenna element, the radiation efficiency of the antenna can be improved. Further, by forming a continuous aperture in a conductive film over plural surfaces of the semiconductor package, the degree of freedom for setting the radiation direction is increased.
A wireless device of a third embodiment differs from those of the first and second embodiments in that in the former, an aperture itself serves as an antenna.
Referring to
By setting the length (in a longitudinal direction) of an aperture 708 in the conductive film 105 to substantially half the wavelength of a desired electromagnetic wave, the aperture 708 can serve as a slot antenna. Namely, the aperture 708 serves as an antenna element. In this case, since the aperture can be formed smaller than in the case where another type of antenna is used, electromagnetic waves can be efficiently radiated and received.
In the wireless device of the third embodiment, a smaller aperture can be formed than in the case where another type of antenna element is mounted on a circuit board and an aperture is formed in a conductive film, with the result that desired electromagnetic waves can be radiated and received more efficiently, thereby realizing a higher shielding performance.
Where a horizontal slot is formed as shown in
As described above, in the third embodiment, the length of the aperture is set to substantially half the wavelength of the desired electromagnetic wave, thereby using the aperture itself as a slot antenna. Since in this case, the aperture can be formed smaller than in the case of using other types of antennas, electromagnetic waves can be efficiently radiated and received with a high shielding effect maintained.
A wireless device according to a fourth embodiment differs from those of the first to third embodiments in that the former employs a slot antenna that comprises an aperture extending from the upper surface of a semiconductor package to a side surface thereof.
Referring to
In a structure utilizing a slot antenna, in order to radiate horizontally polarized waves in a package lateral direction with a high shielding performance realized, vertically elongated aperture is formed in a side surface of the package, as in the third embodiment. However, if the height of the package is less than substantially half the wavelength of a desired electromagnetic wave, the resonant length of the slot cannot be accommodated.
In this case, if an L-shaped aperture 808 extending from a side surface of the package to its top surface as shown in
Since in the fourth embodiment, the aperture is formed in the conductive film over a plurality of surfaces of the semiconductor package, the radiation direction of electromagnetic waves can be set more freely. Further, by using the aperture extended from the side surface to the top surface of the package, the radiation efficiency of the antenna can be enhanced.
A wireless device according to a fifth embodiment differs from the first to fourth embodiments in that the former employs a slot antenna having an aperture thereof extended over an upper surface, a side surface and a lower surface.
Referring to
When an L-shaped slot is used as in the fourth embodiment, the radiation direction of the antenna is obliquely upward from the horizontal plane. Thus, the L-shaped slot antenna is not suitable for horizontal or obliquely downward radiation.
In the fifth embodiment, an aperture 908 is also extended to a metal layer 909 in the circuit board 101 as shown in
In the case where the U-shaped slot shown
Since in the above-described fifth embodiment, the aperture is formed in the conductive film and the metal layer on the circuit board over three surfaces of the semiconductor package, the fifth embodiment can provide an advantage that the radiation direction of electromagnetic waves can be varied more freely to thereby further enhance the radiation efficiency of the antenna, as well as the advantage of the third embodiment.
Referring now to
The information processing apparatus is a generic name of wireless equipments that incorporate one of the above-mentioned wireless devices and perform exchange of data and still and moving images.
As shown in
The wireless device 100 transmits and receives data to and from an external device. The wireless device 100 is formed of one of the semiconductor packages 100 according to the first to fifth embodiments.
The processor (also called a controller) 1001 processes data received from and transmitted to the wireless device 100.
The memory 1002 stores data received from and transmitted to the processor 1001.
Referring then to
In these examples, the wireless equipment examples are a laptop personal computer (laptop PC) 1101 and a mobile terminal 1102. The laptop PC 1101 and the mobile terminal 1102 comprise displays 1103 and 1104 for displaying still and moving images. Each of the laptop PC 1101 and the mobile terminal 1102 also comprises a central processing unit (CPU) (also called a controller), a memory, etc. Each of the laptop PC 1101 and the mobile terminal 1102 further comprises an internal or external wireless device 100, through which data communication is performed using a frequency of, for example, a millimeter-wave band. In the sixth embodiment, the laptop PC 1101 and the mobile terminal 1102 may incorporate the semiconductor package 100 according to any one of the aforementioned embodiments.
Further, if the wireless devices incorporated in the laptop PC 1101 and the mobile terminal 1102 are arranged so that their directions, in which high directivity is obtained, are opposed to each other, data exchange therebetween can be performed with high efficiency.
Although
Referring then to
As shown in
In the above-described sixth embodiment, by installing the wireless device (semiconductor package 100) according to one of the first to fifth embodiments in an information processing apparatus or storage device, such as a laptop PC, a mobile terminal, or a memory card, which performs wireless data communication, data transmission and reception can be performed with high efficiency, with degradation of the shielding effect against undesired electromagnetic waves suppressed, and with degradation of antenna radiation characteristic suppressed.
In the embodiments described above, by forming the aperture in the portion of the conductive film provided on the side surface of the semiconductor package closest to the antenna terminal, degradation of the radiation characteristic of the antenna can be suppressed with degradation of the shielding effect thereof against undesired electromagnetic waves suppressed.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
Number | Date | Country | Kind |
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2012-041832 | Feb 2012 | JP | national |