JP3737864B2 - Semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device configured by connecting a chip formed on a semiconductor wafer and a substrate, and covers a chip covered with a package member, a printed wiring board on which a chip is mounted, and the like.
[0002]
[Prior art]
A normal LSI mounted on a printed wiring board or the like has a structure in which a bare chip cut out from a semiconductor wafer is covered with a package member, and the pad of the bare chip and the pad of the package member are connected by a bonding wire.
[0003]
These recent LSIs tend to be highly integrated with the spread of portable devices. Increasing the integration density of LSI can reduce the number of components mounted on the printed wiring board, thereby improving the reliability and maintainability of the product and reducing the time required for design and development.
[0004]
[Problems to be solved by the invention]
However, as the integration density of LSIs increases, the number of bare chip pads constituting the LSIs increases, and in some cases, hundreds of pads may be required. The conventional bare chip has pads in one or more rows near the outer periphery of the chip, and there is a limit to increasing the number of pads. Further, when the number of pads increases, not only the number of bonding wires increases, but also the wiring on the chip becomes complicated and is easily affected by noise. In particular, recent LSIs often operate at a high clock frequency, and signal leakage (crosstalk) is likely to occur between adjacent signals.
[0005]
On the other hand, LSI package members are provided with external connection terminals (for example, leads) corresponding to the respective pads. Since these external connection terminals have a larger area than the pads, when the number of pads increases, Accordingly, the area of the package member must be increased. Further, as the number of pads increases, the wiring inside the package member becomes more complicated, and troubles such as noise and disconnection are likely to occur.
[0006]
The present invention has been created in view of the above points, and its purpose is to increase the area between the chip and the substrate without increasing the area of the chip and the substrate and preventing the generation of noise. An object of the present invention is to provide a semiconductor device capable of increasing the number of output signals.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the invention of claim 1 is provided with a modulation circuit on a chip, a demodulation circuit on a substrate, and a signal modulated from an output terminal of a semiconductor element formed on the chip. The signal modulated by the system is transmitted, and the signal received by the substrate and demodulated by the demodulation circuit is supplied to the external connection terminal in the substrate. Thus, signals can be transmitted from the chip to the substrate without physically connecting the chip and the substrate.
[0008]
According to the second aspect of the invention, since signals from a plurality of output terminals are multiplexed and then modulated and transmitted by radio waves, it is not necessary to provide a modulation / demodulation circuit for each terminal, and the element structure can be simplified.
[0009]
According to a third aspect of the present invention, a modulation circuit is provided on a substrate, a demodulation circuit is provided on a chip, a signal output from an external connection terminal in the substrate is modulated by a predetermined modulation method, and radio waves are transmitted. The signal received and demodulated by the demodulation circuit is supplied to the semiconductor element in the chip. Accordingly, a signal can be transmitted from the substrate to the chip without physically connecting the chip and the substrate.
[0010]
According to the fourth aspect of the invention, since signals from a plurality of external connection terminals are multiplexed and then modulated and transmitted by radio waves, it is not necessary to provide a modulation / demodulation circuit for each terminal, and the element structure can be simplified.
[0011]
In the invention of claim 5, since the antenna is integrally formed on the chip and the substrate, it is not necessary to attach the antenna separately, and the cost can be reduced and the size can be reduced.
[0012]
According to the sixth aspect of the present invention, in the case of a structure in which the pin attached to the chip is fitted to the pin receiver provided on the substrate, the pin and the pin receiver are used as an antenna. Disappears. Further, since the pin and the pin holder are directly fitted, they are not affected by radio noise.
[0013]
According to the seventh aspect of the invention, since the heat dissipation member attached to the chip is used as an antenna, the heat dissipation member can be used effectively.
[0014]
The invention according to claim 8 performs signal transmission by physically connecting terminals that are not suitable for radio wave transmission such as a power supply terminal and a ground terminal.
[0015]
According to the ninth aspect of the present invention, since a terminal for transmitting a signal bidirectionally such as a data input / output terminal requires a modulation circuit and a demodulation circuit for each terminal, the structure becomes complicated. Perform transmission.
[0016]
In a tenth aspect of the present invention, a terminal through which a signal flows bidirectionally, such as a data input / output terminal, is provided with both a modulation circuit and a demodulation circuit for each terminal. As a result, signal transmission by radio waves is possible regardless of which direction the signal flows.
[0017]
In the eleventh aspect of the invention, when a bare chip is mounted on a printed wiring board, signal transmission by radio waves is performed between the printed wiring board and the bare chip. This eliminates the need to physically connect the printed wiring board and the bare chip.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a semiconductor device to which the present invention is applied will be specifically described with reference to the drawings.
[0019]
The semiconductor device according to the present embodiment includes a chip 1 cut out from a semiconductor wafer and a package member 2 that protects the chip 1. 1A is a diagram showing a partial cross-sectional structure of the chip 1, and FIG. 1B is a diagram showing a partial cross-sectional structure of the package member 2 on which the chip 1 is placed.
[0020]
The semiconductor device shown in FIG. 1 is characterized in that signal transmission between the chip 1 and the package member 2 is performed by radio waves, and digital modulation / demodulation circuits 10 and 20 therefor are formed on both the chip 1 and the package member 2. .
[0021]
A large number of semiconductor elements 4 such as transistors and diodes are formed on a p-Si substrate 3 which is a base substrate of the chip 1. The input / output terminals of these semiconductor elements 4 are digital modulation / demodulation circuits in the chip 1. 10 is connected. The detailed configuration of the digital modulation / demodulation circuit 10 will be described later.
[0022]
A Cu layer 5 that functions as an antenna is formed on the back side of the chip 1, that is, on the side opposite to the element formation surface. The signal modulated by the digital modulation / demodulation circuit 10 is transmitted by radio waves through the Cu layer 5. A protective SIO ₂ layer 6 is formed on the lower layer side of the Cu layer 5.
[0023]
On the other hand, a Cu layer 7 is formed on the upper surface of the package member 2 so as to be in close contact with the SIO ₂ layer 6 of the chip 1. The Cu layer 7 functions as an antenna, and a digital modulation / demodulation circuit 20 and external connection terminals (for example, pads and leads) 8 are formed on the lower layer side of the Cu layer 7.
[0024]
FIG. 2 is a block configuration diagram of the digital modulation / demodulation circuit 10 in the chip 1 and the digital modulation / demodulation circuit 20 in the package member 2. Each of the digital modulation / demodulation circuits 10 and 20 includes a modulation circuit and a demodulation circuit. FIG. 2A shows a block configuration of the modulation circuit formed in the chip 1, and FIG. 2 shows a configuration of a demodulation circuit formed inside. Note that a demodulator circuit similar to that shown in FIG. 2B is provided inside the chip 1, and a modulation circuit similar to that shown in FIG. 2A is provided inside the package member 2, but is omitted in FIG.
[0025]
Hereinafter, signal transmission from the chip 1 side to the package member 2 side will be described with reference to FIGS. The output terminals of each semiconductor element 4 on the chip 1 are connected to the signal multiplexing unit 11 shown in FIG. 2A in groups of a plurality, and the signal multiplexing unit 11 converts a signal from each output terminal into a plurality of bits. Performs multiplexing in units. For example, as shown in FIG. 3, each bit data output from four output terminals is multiplexed. Although FIG. 3 shows an example in which an error correction code is added after each multiplexed bit data, the signal multiplexing unit 11 may output multiplexed data not including the error correction code. .
[0026]
Also, it is desirable to multiplex for each signal of the same type or for signals with substantially the same frequency. For example, the data input / output terminals are multiplexed together at the data input / output terminals, and the address terminals are multiplexed together at the address terminals. It is desirable to do.
[0027]
The multiplexed data output from the signal multiplexer 11 is input to the QPSK modulator 13 as shown in FIG. The QPSK modulator 13 digitally modulates the input bit string. FIG. 4 is a diagram illustrating a schematic configuration of the QPSK modulation unit 13. As shown in the figure, the bit string output from the signal multiplexing unit 11 is converted into 2-bit parallel data f _I (t) and f _Q (t) by the serial / parallel converter 31. One bit data f _I (t) is multiplied by cos (ωt) by the multiplier 32 to be converted to an I signal, and the other bit data f _Q (t) is multiplied by sin (ωt) by the multiplier 33. Converted to Q signal. The I signal and the Q signal are added by the adder 34 to output a QPSK modulation signal S _m (t).
[0028]
As shown in FIG. 4, the QPSK modulation unit 13 performs a process of assigning 2-bit data to four types of phases of a carrier wave, and a QPSK modulation signal that is a modulation result is expressed by Equation (1).
[0029]
S _m (t) = Acos (ωt + θ) (1)
In the formula (1), θ takes any value of π / 4, 3π / 4, 5π / 4, 7π / 4, and A is a constant.
[0030]
Since the four types of QPSK modulation signals expressed by the equation (1) are different in phase by 90 degrees, they do not interfere with each other even when the carrier frequency is increased, and stable communication in the gigahertz band can be performed. .
[0031]
The modulation signal output from the QPSK modulation unit 13 is sent to the Cu layer 5 shown in FIG. 1A, and the Cu layer 5 transmits a radio wave having a phase corresponding to the QPSK modulation signal toward the package member 2.
[0032]
By the way, when the frequency f (f = ω / 2π) of the carrier wave of the QPSK modulator 13 is low, the length of the Cu layer 5 needs to be considerably increased. For example, assuming that the wavelength of the carrier wave is λ (m), the frequency of the radio wave is f (Hz), and the speed of the radio wave is v (m / s), the relationship of equation (2) is established.
[0033]
λ = v / f (2)
Since the speed of the radio wave is v≈3 × 10 ⁸ (m / s), when f = 1 (GHz), λ = 30 (cm). In general, since the antenna needs to have a length of λ / 2, the length of the Cu layer 5 needs to be 15 (cm), and it is practically impossible to form it in the chip 1. Therefore, it is desirable that the frequency of the carrier wave be several tens of GHz or more.
[0034]
The radio wave transmitted from the Cu layer 5 in the chip 1 is received by the Cu layer 7 in the package member 2 and converted into an electric signal. A QPSK demodulator 21 shown in FIG. 2B is connected to the Cu layer 7 and converts the QPSK modulated signal into the original 2-bit data. The output of the QPSK demodulator 21 is input to a signal separator 23 and separated into data before multiplexing. Each separated bit data is input to external connection terminals 8 provided on the package member 2, and these external connection terminals 8 are connected to a pattern on a printed wiring board on which a semiconductor device is mounted, for example.
[0035]
2 illustrates an example in which a signal is transmitted from the chip 1 side to the package member 2 side, it is also possible to transmit a signal from the package member 2 side to the chip 1 side.
[0036]
As described above, since the semiconductor device of the present embodiment performs signal transmission between the chip 1 and the package member 2 by radio waves, the chip 1 and the package member 2 are physically connected between the chip 1 and the package member 2 via bonding wires or the like as in the past. There is no need to connect, and there is no need to form a wiring region. Therefore, even an LSI bare chip having a large number of signal terminals can be stored in the small package member 2 without difficulty.
[0037]
In addition, since a plurality of signals are multiplexed and transmitted, it is not necessary to provide a modulation / demodulation circuit for each signal terminal, and the structure of the semiconductor device can be simplified and the outer diameter can be reduced. Furthermore, since the Cu layer 5 formed integrally with the semiconductor element 4 is used as an antenna, it is not necessary to attach an antenna separately, and the cost of components can be prevented from increasing. Further, since the Cu layer 5 in the chip 1 and the Cu layer 7 in the package member 2 are disposed in close contact with the SiO ₂ layer sandwiched therebetween, radio wave interference can be reliably prevented.
[0038]
FIG. 5 is a perspective view showing the appearance of the chip 1 of the present embodiment. The chip 1 includes an area 101 in which a receiver to which an external signal is input is formed, an area 102 in which a driver that outputs an external signal is formed, and a bidirectional buffer that bidirectionally exchanges signals with the outside. A formed region 103 is provided. A demodulator circuit is formed below the chip 1 corresponding to the receiver formation region 101, a modulation circuit corresponding to the driver formation region 102, and a modulation / demodulation circuit corresponding to the bidirectional buffer formation region 103. Yes. In addition, a region 104 in which a large number of pads are formed is provided on the upper surface of the chip 1, and these pads are physically connected to the package member 2 via bonding wires or the like. As the terminals formed in this region 104, for example, a power supply terminal and a ground terminal through which a large amount of current flows, a clock terminal to which a high-frequency clock signal is input, and the like can be considered.
[0039]
If a digital modulation / demodulation circuit capable of modulation and demodulation is provided in the chip 1 and the package member 2, the structure of the semiconductor device becomes complicated. Therefore, either the chip 1 or the package member 2 is provided with only the modulation circuit, Only the demodulation circuit may be provided on the other side. For example, in FIG. 6A, a demodulating circuit is formed below the region 105 where the receiver is formed, and a pad is formed in the region 106 for the driver and physically connected to the package member 2 by a bonding wire or the like. An example of connection is shown. In this case, since signal transmission by radio waves is not performed, the digital modulation circuit as shown in FIG. 2A is unnecessary, and each output terminal of the semiconductor element 4 is directly connected to the pad of the region 106 described above. That's fine. On the other hand, FIG. 6B shows an example in which a modulation circuit is formed in the area 107 where the driver is formed, and a pad is formed in the area 108 for the receiver. In this case, since signal reception by radio waves is not performed, a digital demodulation circuit as shown in FIG. 2B is unnecessary, and if each input terminal of the semiconductor element 4 is directly connected to the pad of the region 107 described above. Good. Thus, if one of the modulation circuit and the demodulation circuit is provided in the chip 1 and the package member 2, the structure of the semiconductor device can be simplified.
[0040]
In FIG. 1A, an example in which radio waves are transmitted from the lower surface of the p-Si substrate 3, that is, the surface opposite to the surface on which the semiconductor element 4 is formed has been described, but acts as an antenna on the surface on which the semiconductor element 4 is formed. A Cu layer may be formed, and the element formation surface may be disposed opposite to the package member 2 to join them together.
[0041]
FIG. 2 shows an example in which receivers, drivers, and the like are formed in different regions, but the layout on the chip 1 can be arbitrarily changed. For example, the receivers and drivers are formed along the outer periphery of the chip 1. May be. In addition, only a terminal through which a signal having a predetermined frequency or higher flows may be transmitted by radio waves, or conversely, only a terminal through which a signal having a frequency lower than a predetermined frequency may be transmitted by radio waves.
[0042]
Further, FIG. 1 illustrates an example in which signal transmission between the chip 1 and the package member 2 is performed by radio waves. However, in the case of mounting between the package member 2 and the printed wiring board or without providing the package member 2, the chip 1 is used. The signal transmission between the printed wiring board and the printed wiring board may be performed by radio waves. In this case, a demodulating circuit is formed on the printed wiring board corresponding to the modulation circuit formed on the chip 1 or the package member 2, and the printed wiring board corresponding to the demodulating circuit formed on the chip 1 or the package member 2 is formed. A modulation circuit may be formed.
[0043]
In the semiconductor device illustrated in FIG. 2, the example in which the multiplexed signal is QPSK modulated has been described. However, the modulation scheme is not limited to QPSK modulation, and various modulation schemes such as BPSK modulation and multilevel modulation can be applied. Further, modulation / demodulation may be performed separately for each signal without multiplexing.
[0044]
In FIG. 1, the example in which the Cu layers 5 and 7 are used as antennas has been described. However, when the pins attached to the chip 1 are fitted to the pin holders of the package member 2, the pins and the pin holders are used as antennas. Also good. When a heat radiating member is attached to the chip 1, an antenna may be formed on a part of the heat radiating member.
[0045]
【The invention's effect】
As described above in detail, according to the present invention, since signal transmission between the chip and the substrate is performed by radio waves, it is not necessary to physically connect the chip and the substrate using a bonding wire or the like, and the wiring region Need not be formed. For this reason, the outer diameter dimension of the board | substrate which mounts a chip | tip can be made small.
[0046]
Further, since a plurality of signals are multiplexed and modulated, it is not necessary to provide a modulation / demodulation circuit for each signal terminal, the structure of the semiconductor device can be simplified, and the outer diameter can be reduced.
[Brief description of the drawings]
FIG. 1A is a diagram showing a sectional structure of a chip, and FIG. 1B is a diagram showing a sectional structure of a package member.
FIG. 2 is a block configuration diagram of a digital modulation / demodulation circuit in a chip and in a package member.
FIG. 3 is a diagram illustrating an example of multiplexing signals from four output terminals.
FIG. 4 is a diagram illustrating a schematic configuration of a QPSK modulation unit.
FIG. 5 is a perspective view showing an appearance of a chip according to the present embodiment.
6A is a diagram showing a semiconductor device having a demodulation circuit without a modulation circuit, and FIG. 6B is a diagram showing a semiconductor device having a modulation circuit without a demodulation circuit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Chip 2 Package member 3 p-Si substrate 4 Semiconductor element 5, 7 Cu layer 6 SiO ₂ layer 8 External connection terminal 10, 20 Digital modulation / demodulation circuit

Claims (12)

In a semiconductor device having a substrate on which a chip cut from a semiconductor wafer is mounted,
The chip multiplexes signals output from a plurality of output terminals of a semiconductor element formed on the chip, and modulates a signal multiplexed by the multiplexing circuit with a predetermined modulation method. and a modulation circuit,
The substrate includes a demodulation circuit that demodulates a signal modulated by the predetermined modulation method, an external connection terminal that outputs a signal demodulated by the demodulation circuit to the outside of the substrate, and a signal demodulated by the demodulation circuit A signal separation circuit that separates the signal before multiplexing and supplies the signal to the external connection terminal ,
A semiconductor device, wherein a radio wave corresponding to a signal modulated by the predetermined modulation method is transmitted and received between the chip and the substrate. In a semiconductor device having a substrate on which a chip cut from a semiconductor wafer is mounted,
The board includes a plurality of external connection terminals that capture signals from outside the board, a multiplexing circuit that multiplexes signals input to the plurality of external connection terminals, and a signal that is multiplexed by the multiplexing circuit A modulation circuit that modulates the signal with a predetermined modulation method,
The chip has a demodulating circuit that demodulates a signal modulated by the predetermined modulation method, and a signal that is supplied to each input terminal of the chip after being separated into a signal before multiplexing the signal demodulated by the demodulating circuit A semiconductor device comprising: a separation circuit; and a semiconductor element that performs a predetermined circuit operation based on a signal separated by the signal separation circuit . In claim 1 or 2,
The chip and the substrate are formed with antennas corresponding to the modulation circuit and the demodulation circuit,
A semiconductor device, wherein a shape and an area of the antenna are determined in accordance with a frequency of a carrier wave of the modulation circuit . In any one of Claims 1-3,
Of the input / output terminals formed on the chip, at least some of the electrodes including the power supply terminal and the ground terminal do not perform transmission / reception by radio waves, and the external connection is formed correspondingly on the substrate. A semiconductor device which is connected to a terminal through a conductive material . In any one of Claims 1-4,
The semiconductor device according to claim 1, wherein the substrate is a printed wiring board, and the chip is mounted on the printed wiring board in a bare state . In a semiconductor device having a substrate on which a chip cut from a semiconductor wafer is mounted,
The chip includes a modulation circuit that modulates a signal output from an output terminal of a semiconductor element formed on the chip by a predetermined modulation method,
The substrate includes a demodulation circuit that demodulates a signal modulated by the predetermined modulation method, and an external connection terminal that outputs the signal demodulated by the demodulation circuit to the outside of the substrate,
Transmitting and receiving radio waves according to the signal modulated by the predetermined modulation method between the chip and the substrate,
Of the input / output terminals formed on the chip, the input / output terminals through which signals flow bidirectionally do not perform transmission / reception by radio waves, and are electrically connected to the external connection terminals formed corresponding to the substrate. A semiconductor device which is connected through a conductive material . In claim 6,
The chip includes a multiplexing circuit that multiplexes signals output from the plurality of output terminals and supplies the multiplexed signals to the modulation circuit,
2. The semiconductor device according to claim 1, wherein the substrate includes a signal separation circuit that separates a signal demodulated by the demodulation circuit into a signal before multiplexing and supplies the signal to the external connection terminal . In semiconductors devices having a substrate cut chip is mounted from the semiconductor wafer,
The substrate includes an external connection terminal that captures a signal from the outside of the substrate, and a modulation circuit that modulates the signal captured by the external connection terminal by a predetermined modulation method,
The chip includes a demodulation circuit that demodulates a signal modulated by the predetermined modulation method, and a semiconductor element that performs a predetermined circuit operation based on the signal demodulated by the demodulation circuit,
Of the input / output terminals formed on the chip, the input / output terminals through which signals flow bidirectionally do not perform transmission / reception by radio waves, and are electrically connected to the external connection terminals formed corresponding to the substrate. A semiconductor device which is connected through a conductive material . In claim 8,
The substrate includes a multiplexing circuit that multiplexes signals input to the plurality of external connection terminals and supplies the multiplexed signals to the modulation circuit,
The semiconductor device according to claim 1, wherein the chip includes a signal separation circuit that separates a signal demodulated by the demodulation circuit into a signal before multiplexing and supplies the signal to each input terminal of the semiconductor element . In any one of Claims 6-9,
The chip and the substrate are formed with antennas corresponding to the modulation circuit and the demodulation circuit,
A semiconductor device, wherein a shape and an area of the antenna are determined in accordance with a frequency of a carrier wave of the modulation circuit . In any one of Claims 6-10,
Of the input / output terminals formed on the chip, at least some of the electrodes including the power supply terminal and the ground terminal do not perform transmission / reception by radio waves, and the external connection is formed correspondingly on the substrate. A semiconductor device which is connected to a terminal through a conductive material . In any one of Claims 6-11,
  The semiconductor device according to claim 1, wherein the substrate is a printed wiring board, and the chip is mounted on the printed wiring board in a bare state.

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