JP4026052B2 - Semiconductor device and semiconductor device design method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device and a method for designing a semiconductor device, and more particularly to a semiconductor device in which a high-frequency line of a multilayer printed circuit board is a chip-type line and a method for designing the semiconductor device.
[0002]
[Prior art]
Generally, a high-frequency line of a high-frequency (RF) circuit used in wireless communication, LAN, or the like is configured as a microstrip line or a strip line (hereinafter, the micro strip line and the strip line are simply referred to as a strip line) and is formed on a printed circuit board. Wired. The strip line is composed of a ground plane connected to the ground electrode and a signal line facing the ground plane, and the width and length of the signal line or the dielectric constant of the dielectric layer between the signal line and the ground plane. The desired characteristic impedance (generally 50Ω) is adjusted by adjusting the rate and the separation distance.
[0003]
[Problems to be solved by the invention]
By the way, it is well known that if the impedance matching is not properly taken, the high-frequency line causes a signal reflection or the like at a location where the matching is not achieved, and the signal propagation characteristics deteriorate. When the characteristic impedance of the strip line formed on the printed circuit board does not match the desired impedance, the characteristic impedance is adjusted by cutting the formed signal line with a laser or by redesigning the printed circuit board. There was a need.
[0004]
The high-frequency line can be formed using a coaxial line instead of being formed on the printed circuit board. In this case, impedance matching is possible by adjusting the characteristic impedance of the coaxial line. However, when a coaxial line is used, it is necessary to mount a connector terminal on the printed circuit board and connect the coaxial line to the printed circuit board. This increases the number of assembly steps and increases the manufacturing cost. In addition, when a thin coaxial line is used to reduce the size of the device, the coaxial line is disconnected, and the reliability of the high-frequency line is lowered.
[0005]
As a technique for solving the above problems, Japanese Utility Model Laid-Open No. 5-6911 and Japanese Utility Model Laid-Open No. 5-8010 have chip-type strips in which high-frequency lines are formed as chip-type components in place of wires arranged on a printed circuit board. A technique for wiring to a line is described. In this technique, impedance matching is facilitated by preparing chip-type strip lines having a plurality of characteristic impedances and replacing them on the substrate. Further, since the signal line is formed inside the chip component, the possibility of disconnection is low and the high-frequency line is highly reliable.
[0006]
Here, there exists a multilayer printed circuit board as what divides the inside of a printed circuit board into several layers, and gives wiring to each layer. In the multilayer printed board, a plurality of wirings are applied to each of the mutually insulated layers, so that the degree of integration of the semiconductor device can be increased and the device can be miniaturized. However, in the case of a multilayer printed board, when the stripline is applied to the inner layer, there is a problem that the impedance of the stripline cannot generally be adjusted after the printed board is manufactured.
[0007]
Further, the wiring constituting the strip line requires one or more layers to form the ground plane and one layer to form the signal lines, and it is necessary to use at least two wiring layers in total. Furthermore, when the printed circuit board has a narrow layer spacing, in order to obtain a characteristic impedance by securing the distance between the ground plane and the signal line, one or more layers are not provided between the ground plane and the signal line. There is a case where one high frequency line occupies a total of 3 to 4 or more wiring layers. This has hindered miniaturization and integration of the device. In the multilayer printed circuit board, a strip line that can easily match the impedance of the high-frequency line and can efficiently use the wiring layer has not been known.
[0008]
The present invention solves the above problems, and can easily perform impedance matching of a high-frequency line after manufacturing a multilayer printed circuit board, and can efficiently use the wiring layer of the multilayer printed circuit board, and a semiconductor device design method The purpose is to provide.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a semiconductor device according to the present invention includes a printed circuit board having at least one internal strip line and at least two printed circuit boards mounted on the printed circuit board and connected to each other via the internal strip line. In a semiconductor device including a semiconductor chip, a chip-type strip line for connecting the semiconductor chips is mounted on the multilayer printed board.
[0010]
In the semiconductor device of the present invention, a part of the high-frequency line that occupies a plurality of wiring layers of the multilayer printed wiring board is configured as a chip-type component, so that the degree of freedom of wiring of the internal wiring layer of the multilayer printed board is increased. The high-frequency line arranged in the internal wiring layer occupies at least two wiring layers, but this wiring layer can be used for low-frequency wiring or the like. Further, by using a high-frequency line as a chip component, automatic mounting is possible as in the case of an IC chip and the like, and the manufacturing process is not increased.
[0011]
A method for designing a semiconductor device according to the present invention is a method for designing a semiconductor device according to the present invention, wherein the chip-type stripline has at least one of a capacitive component and an inductive component.
[0012]
In the semiconductor device design method of the present invention, the impedance design is facilitated by making the high-frequency line into a chip-type component. By providing the chip-type strip line with a desired capacitance component and an inductive component, the stray capacitance component and the inductive component of the multilayer printed board can be offset.
[0013]
In the semiconductor device of the present invention, it is preferable that the chip-type strip line has a characteristic impedance different from that of the internal strip line. In this case, when impedance matching cannot be achieved with the internal strip line, impedance matching can be achieved using a chip-type strip line.
[0014]
In the semiconductor device of the present invention, it is preferable that a surface layer strip line is further formed on the surface layer of the printed circuit board. Since the chip-type stripline is shielded by the ground plane, signal interference is unlikely to occur even if a surface layer stripline is formed immediately below the chip-type stripline.
[0015]
In the semiconductor device of the present invention, it is preferable that the chip type strip line and the surface layer strip line intersect each other. In this case, it is not necessary to cross the portion where the wiring intersects using a coaxial wiring or the like, and the reliability of the high-frequency wiring is increased.
[0016]
The semiconductor device of the present invention preferably includes a plurality of the chip type strip lines, and the characteristic impedances of the plurality of chip type strip lines are different from each other.
The characteristic impedance of the chip type strip line is determined by parameters such as the width of the signal line. Impedance matching is facilitated by preparing a chip-type strip line having a plurality of characteristic impedances, and replacing and mounting them.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, with reference to the drawings, the present invention will be described in more detail based on exemplary embodiments of the present invention. FIG. 1 is a schematic plan view of a semiconductor device using a multilayer printed board according to an embodiment of the present invention. FIG. 2 shows a II-II cross section of FIG. In the semiconductor device, IC chips 103 and 104 are mounted on a multilayer printed circuit board 100, and the IC chips 103 and 104 are connected by the surface of the printed circuit board, an inner layer, or a chip-type strip line 102.
[0018]
On the surface layer of the multilayer printed circuit board 100, a land pattern 105 for component mounting, a surface low frequency signal line 108, and a signal line 106 of a surface layer strip line are formed. On the land pattern 105, an IC chip 103, an IC chip 104, and a chip type strip line 102 are mounted. The signal line 106 of the surface layer strip line and the surface layer low frequency signal line 108 intersect the chip type strip line 102 as shown in FIG.
[0019]
The wiring layers in the multilayer printed circuit board are sequentially counted from the upper surface. When the i-th wiring layer is called the i-th wiring layer, the first wiring layer is in contact with the signal line 106 of the surface layer strip line. The ground (GND surface) 110 is arranged. In the third wiring layer, the signal line 107 of the inner layer strip line connected from the terminal of the IC chip 103 to the IC chip 104 through the contactor is arranged. In the second and fourth wiring layers, the GND surface 112 is disposed at a position facing the signal line 107 of the inner layer strip line. Here, the microstrip line formed on the surface layer and the strip line formed on the inner layer are general high-frequency transmission means used in a multilayer printed board.
[0020]
The chip-type stripline 102 has a stripline structure in which the signal line 113 and the GND surface 115 are opposed to each other via a dielectric, and is configured as a chip component. The chip-type stripline 102 is soldered to the land pattern 105 and electrically connected to the multilayer printed circuit board 100 in the same manner as other components mounted on the multilayer printed circuit board. For example, a high-frequency signal output from the IC 103 configured as a high-frequency signal source is transmitted on the load side via the signal line 106 of the surface layer strip line, the signal line 107 of the inner layer strip line, and the signal line 113 of the chip-type strip line 102. Input to the IC 104.
[0021]
In this embodiment, in addition to the surface layer strip line and the inner layer strip line, a chip-type strip line 102 having a built-in strip line is used as a high-frequency signal transmission means. The impedance of the chip-type strip line 102 is determined by the width of the signal line 113 constituting the strip line, the relative dielectric constant of the dielectric, the separation distance between the signal line 113 and the GND surface 115, and the like. Impedance adjustment can be achieved by preparing a plurality of chip-type striplines 102 having different parameters, selecting those having good characteristics from the chip-type striplines 102 having different characteristic impedances, and mounting them on a multilayer printed board. It can be done easily. For this reason, even when impedance matching cannot be achieved after the printed circuit board is manufactured, impedance adjustment can be performed without redesigning the multilayer printed circuit board, and signal reflection loss and the like can be reduced.
[0022]
If the high-frequency line is configured as a chip component as in this embodiment, a plurality of wiring layers of the multilayer printed board occupied by the high-frequency line can be used for another wiring. By effectively using the wiring layer in this way, the printed circuit board can be integrated and miniaturized. In addition, in order to cross two high-frequency lines without interfering with each other's signals, in the conventional multilayer printed circuit board wiring, at least five layers (two on the surface microstrip line and three on the inner layer strip line) However, in this embodiment, since the chip-type strip line and the surface layer strip line are crossed, the wiring layer occupied by the high-frequency line is two layers. Since the chip-type strip line is shielded by the ground plane, it is possible to design a high-frequency circuit without considering interference with the signal of the surface layer wiring. Also from this, the degree of freedom of wiring of the multilayer printed board is increased, and the multilayer printed board can be miniaturized and integrated.
[0023]
Chip-type components can be automatically mounted in the same manner as other components such as IC chips. For this reason, compared with the case where a coaxial line is used as a high frequency line, a manufacturing process becomes simple. Further, the possibility of occurrence of a malfunction due to disconnection or the like is reduced, and the reliability of the high-frequency line is increased. When configuring a strip line on a multilayer printed circuit board, it was necessary to manage the line width, dielectric thickness, etc. of the strip line on the printed circuit board for each design of the multilayer printed circuit board. By using this part, it becomes easy to manage the characteristic impedance, and a high-reliability high-frequency line can be formed.
[0024]
In the above embodiment, the case where the number of signal lines of the chip-type strip line is one has been described. However, the same effect can be obtained in the case of a high-frequency line having two or more signal lines. Further, the characteristic impedance of the chip-type strip line has been described on the assumption that it has only a pure resistance component. However, by intentionally including a capacitive component and an inductive component in the chip, the multilayer printed circuit board has a characteristic impedance. Impedance matching that cancels out stray capacitance components and inductive components becomes possible, and it is possible to reduce components such as chip capacitors for impedance adjustment and chip inductances that have been conventionally used. Further, the high-frequency line configured using the chip-type strip line is not limited to the IC chip or the package, and any one of the high-frequency lines arranged on the multilayer printed board may be configured as the chip-type strip line. .
[0025]
Although the present invention has been described based on the preferred embodiment, the semiconductor device and the method for designing the semiconductor device are not limited to the above embodiment, and various configurations are possible from the configuration of the above embodiment. The semiconductor device and the semiconductor device design method that have been modified and changed are also included in the scope of the present invention.
[0026]
【The invention's effect】
As described above, according to the semiconductor device and the semiconductor device design method of the present invention, the high-frequency line is configured as a chip-type component in the multilayer wiring printed board. For this reason, impedance matching can be easily performed by preparing a plurality of chip-type strip lines having different characteristic impedances in advance and selecting and mounting a chip-type strip line having a desired impedance characteristic. The time and cost due to the redesign of the multilayer printed circuit board can be reduced. Also, by moving the high-frequency line from the multilayer printed circuit board to chip-type components, the space used as the high-frequency line that occupies multiple wiring layers in the multilayer printed circuit board can be used for other signal lines and power lines. It becomes like this. For this reason, the wiring efficiency of the wiring layer is improved, and the semiconductor device on which the multilayer printed board is mounted can be downsized.
[Brief description of the drawings]
FIG. 1 is a schematic view of a multilayer printed wiring board using chip-type high-frequency lines according to an embodiment of the present invention as viewed from above.
2 is a cross-sectional view taken along the line II-II in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100: Multilayer printed circuit board 102; Chip-type stripline 103, 104: IC chip 105: Component mounting land pattern 106: Surface layer microstrip line signal line 107: Inner layer stripline signal line 108: Low frequency signal line 110,112 115: GND surface 113: signal line

Claims (6)

A semiconductor device comprising: a printed circuit board having at least one layer of internal stripline; and at least two semiconductor chips or packages mounted on the printed circuit board and connected to each other via the internal stripline.
A semiconductor device comprising a chip-type strip line for connecting between the semiconductor chips or packages mounted on the multilayer printed board. The semiconductor device according to claim 1, wherein the chip-type strip line has a characteristic impedance different from that of the internal strip line. The semiconductor device according to claim 1, further comprising a surface layer strip line formed on a surface layer of the printed circuit board. The semiconductor device according to claim 3, wherein the chip-type strip line and the surface layer strip line intersect each other. 5. The semiconductor device according to claim 1, wherein a plurality of the chip-type strip lines are provided, and the characteristic impedances of the plurality of chip-type strip lines are different from each other. A method for designing a semiconductor device according to claim 1,
A method for designing a semiconductor device, wherein the chip-type strip line has at least one of a capacitive component and an inductive component.

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