The present invention relates to semiconductor devices, more particularly, a semiconductor device including a coil.
The increase in the speed of inter-chip communication raises expectations for inter-chip wireless communication techniques. Wireless communication is also expected to be effective in the pass/fail determination of acceptable chip products, in addition to increasing the communication rate. Inter-chip wireless communication is based on the two schemes of capacitive coupling and magnetic coupling. Magnetic coupling is advantageous in that communication is allowed even between three or more chips. According to inter-chip wireless communication technique employing magnetic coupling, communication in 1 Tbit/s is realized by aligning 1000 channels having a transfer rate of 1 Gbit/s. Electric power normalized at the rate, i.e. the communication energy per bit, now attains 0.14 pJ/bit. This is disclosed by Tadahiro Kuroda in “Ultra-low power Short-range Wireless Mobile Information Systems”, the Institute of Electronics, Information and Communication Engineers of Japan (IEICE), Vol. 90, No. 3, pp. 191-195 (Non-Patent Document 1).
A conventional inter-chip wireless communication approach is disclosed in Japanese Patent Laying-Open No. 2005-228981 (Patent Document 1), for example. The electronic circuit of Patent Document 1 has three layers of an LSI chip stacked, and a bus for interconnection of the three layers of LSI chips is formed. At each of the three layers of LSI chips, a transmission coil and reception coil are formed. The transmission coil and reception coil are formed on the LSI chip. Accordingly, communication is realized between vertically-located LSI chips. In communication thereof, it is necessary to set the position of the coils in alignment since deviation in the distance between the layers and/or misalignment in plane between upper and lower coils will disturb the communication.
Since the coil had an axis parallel to the normal line of the main plane of the LSI chip in conventional wireless communication techniques, communication in a direction other than the vertical direction was not possible. Therefore, an object of the present invention is to provide a semiconductor device allowing communication in a direction other than the direction of the normal line of the main plane of a semiconductor package.
A semiconductor device according to an embodiment of the present invention includes a semiconductor package, and a coil. The semiconductor package includes a main plane and a connection electrode protruding from the main plane. The coil has at least a portion provided at the semiconductor package. The axis of the coil is inclined with respect to the normal line of the main plane.
By the semiconductor device according to an embodiment of the present invention, communication in a direction other than the direction of the normal line of the main plane of a semiconductor package is allowed.
Embodiments of the present invention will be described hereinafter based on the drawings.
Semiconductor package SP1 includes a mold resin MR1, a resin substrate RS1, and a plurality of solder balls SB1. Mold resin MR1 is disposed on a rectangular resin substrate RS1, having a plane configuration identical to that of resin substrate RS1. A semiconductor chip (not shown) is embedded in mold resin MR1. A plurality of solder balls SB 1 are arranged at the bottom face of resin substrate RS1. Semiconductor package SP1 is electrically connected with semiconductor package SP2 through the plurality of solder balls SB1. Similarly, semiconductor package SP2 includes a mold resin MR2, a resin substrate RS2, and a plurality of solder balls SB2. Mold resin MR2 has a rectangular shape, and is arranged at the center area of the top face of rectangular resin substrate RS2. A semiconductor chip (not shown) is embedded in mold resin MR2. A plurality of solder balls SB2 are arranged at a bottom face of resin substrate RS2. Semiconductor package SP2 is electrically connected with semiconductor package SP3 through the plurality of solder balls SB2. Semiconductor package SP3 includes a mold resin MR3, a resin substrate RS3, and a plurality of solder balls SB3. Mold resin MR3 has a rectangular shape, and is arranged at the center area of the top face of rectangular resin substrate RS3. A semiconductor chip (not shown) is embedded in mold resin MR3. A plurality of solder balls SB3 (connection electrode) are arranged at a bottom face LS (main plane) of resin substrate RS3. Semiconductor package SP3 is electrically connected with substrate SUB through the plurality of solder balls SB3.
Referring particularly to
Referring particularly to
An example of a wireless communication method in the semiconductor device of the present embodiment, between package-on-package PP1 and package-on-package PP2, will be described hereinafter.
A transmission clock (synchronizing signal) Txclk, and transmission data Txdata in synchronism with the transmission clock are input to the transmission circuit. The input transmission data Txdata is held in storage element FF to be input to first transmission buffer INV2 and second transmission buffer INV3. Delay buffer DB that is a delay element is provided between storage element FF and first transmission buffer INV2, causing a difference in the input time to first transmission buffer INV2 and the input time to second transmission buffer INV3. The output of first transmission buffer INV2 and the output of second transmission buffer INV3 are connected to each of the ends of transmission coil L1. By such a configuration, current flows to transmission coil L1 for just the signal propagation delay time of delay buffer DB only when there is change in the transmission data.
The reception circuit includes transistors T1-T10, resistors R1 and R2, NAND circuits NAND1 and NAND2, and a reception buffer INV1. These elements are provided in the semiconductor chip of package-on-package PP2. The reception circuit further includes a reception coil L2 corresponding to coil CO (
An externally applied reception clock (synchronizing signal) Rxclk is input to the reception circuit. Reception coil L2 has either end electrically connected to a gate terminal of each of transistors T2 and T3. Transistors T2 and T3 receive a signal from reception coil L2. Reception coil L2 also has either end electrically connected to a bias voltage Vbias through each of resistors R1 and R2. Accordingly, the center voltage of the amplitude generated across reception coil L2 at the time of signal reception can be set at a level optimum for signal amplification. The source terminals of transistors T2 and T3 are electrically connected to transistor T1 for tail current source generation. Transistor T1 has its source terminal connected to ground, and receives reception clock Rxclk at its gate terminal. At the drain side of transistors T2 and T3, a set of transistors T5 and T8, and a set of transistors T6 and T9 constitute an inverter. These inverters are connected in a loop. The wiring joining the inverters are electrically connected to each of NAND circuits NAND1 and NAND2. NAND circuits NAND1 and NAND2 constitute a latch. The data received at a differential amplifier has its value altered in synchronism with reception clock Rxclk applied to transistor T1. By NAND circuits NAND1 and NAND2, a value is taken in with the reception signal as digital data only when there is change in the value. The value is maintained during the period where there is no change in the input value. For the purpose of precharging the differential amplifier and holding the latched value during an L (low) period of reception clock Rxclk, each of transistors T7 and T10 is connected at the reception circuit. Transistor T4 is connected to the reception circuit to prevent erroneous inversion of the value of reception data Rxdata caused by the effect of noise generated by transistors T7 and T10 despite that there is no change in the reception signal from reception coil L2.
By the current change at points B-C of the transmission coil, voltage is generated at reception coil L2. The center voltage of the oscillation of the voltage is Vbias. This voltage change at the reception coil is amplified by the latching differential amplifier, and the value is held by the latch, whereby reception data Rxdata exhibits the change of points B-C.
Transmission data Txdata does not change at point C and is kept at the H level. In this case, the input to transmission coil L1 at point C does not change. The voltage of reception coil L2 neither changes. As a result, reception data Rxdata is maintained.
When transmission data Txdata is driven to an L level from an H level at point C, this signal is introduced into storage element FF at point D to be immediately input to second transmission buffer INV3, causing the output of second transmission buffer INV3 to be changed from an L level to an H level. At this stage, the output of first transmission buffer INV2 is delayed in the change from the L level to the H level by delay buffer DB. Current flows from second transmission buffer INV3 towards first transmission buffer INV2. At an elapse of the delay time of delay buffer DB, the output of first transmission buffer INV2 attains an H level. The outputs of first and second transmission buffers INV2 and INV3 become equal potential. As a result, current does not flow at transmission coil L1.
By the current change at points D and et seq. of the transmission coil, voltage is generated at reception coil L2. The center voltage of the oscillation of the voltage is Vbias. This voltage change of the reception coil is amplified by a latching differential amplifier, and the value is held by the latch, causing reception data Rxdata to exhibit the change indicated at points D and et seq. By the method described above, data is transmitted from package-on-package PP1 to package-on-package PP2 based on the change in the magnetic field generated from coil CO1.
Package-on-package PP of the present embodiment includes a semiconductor package SP3 having a bottom face LS and a solder ball SB3 protruding from bottom face LS, and a coil CO having at least a portion provided at semiconductor package SP3. Axis AX of coil CO is inclined with respect to normal line NL of bottom face LS.
According to package-on-package PP of the present embodiment, communication in a direction other than the direction of the z axis is allowed since axis AX of coil CO is inclined with respect to normal line NL of bottom face LS.
Further, communication within the xy plane is allowed since axis AX is orthogonal to normal line NL.
Moreover, since at least a portion of the coil is configured by a conducting wire, the coil can be formed mechanically.
In addition, the cost to mount the coil can be reduced, as compared to the case where a coil is provided for each semiconductor package, since one coil CO is shared among semiconductor packages SP1-SP3.
The configuration of
As described above, the axis of the coil in the present invention is at least inclined with respect to the normal line (z axis) of the main plane (xy plane) of the semiconductor package.
Referring particularly to
Conductor layer CL1 has its left end portion electrically connected with the left end portion of conductor layer CL2 via a solder ball SB1a (upper connection electrode) of semiconductor package SP1 (upper semiconductor package), through hole THa, and a solder ball SB2a of semiconductor package SP2. Similarly, conductor layer CL1 has its right end portion electrically connected with the right end portion of conductor layer CL2 through a solder ball SB1b (upper connection electrode) of semiconductor package SP1, through hole THb, and a solder ball SB2b of semiconductor package SP2. As a result, conductor layer CL1, solder ball SB1a, through hole THa, solder ball SB2a, conductor layer CL2, solder ball SB2b, through hole THb, and solder ball SB1b constitute coil CO. Axis AX of coil CO (
As shown in
The remaining configuration of package-on-package PP is similar to that of the package-on-package of the first embodiment. Corresponding members have the same reference character allotted, and description thereof will not be repeated.
According to package-on-package PP of the present embodiment, advantages similar to those of the package-on-package of the first embodiment can be provided.
In addition, according to package-on-package PP of the present embodiment, advantages similar to those of the package-on-package of the first embodiment can be provided. In addition, since at least a portion of coil CO is configured by solder balls SB1a and SB1b, the mechanical work of winding a coil can be dispensed with. Therefore the cost and time required for mounting a coil can be reduced.
Furthermore, since a portion of coil CO is configured by conductor layer CL2 provided in semiconductor package SP3 and conductor layer CL1 provided in semiconductor package SP1, the cost and time required for mounting a coil can be further reduced. Moreover, the radius of the coil can be increased, as compared to the case where a coil is formed at the semiconductor chip.
Semiconductor package SP4 includes three semiconductor chips ST1-ST3 formed of silicon, for example, a resin substrate RS4, a plurality of solder balls SB4 (connection electrode) protruding from bottom face LS, and a mold resin MR. Semiconductor chip ST1 is stacked on resin substrate RS4. Semiconductor chip ST2 is stacked on semiconductor chip ST1. Semiconductor chip ST3 is stacked on semiconductor chip ST2. Semiconductor chips ST1-ST3 are sealed with mold resin MR.
In the vicinity of the four corners of semiconductor package SP having a rectangular plane configuration, electrodes EL1-EL4 formed of Au, for example, are provided. Each of electrodes EL1-EL4 penetrates semiconductor chips ST1-ST3. Each of semiconductor chips ST1-ST3 is electrically connected with each other by electrodes EL1-EL4. A conductor layer CL3 is formed in semiconductor chip ST1. The upper end of electrode EL1 (through electrode) and the upper end of electrode EL2 (through electrode) are electrically connected with each other through conductor layer CL3. Similarly, a conductor layer CL4 is formed in semiconductor chip ST3. The lower end of electrode EL1 and the lower end of electrode EL2 are electrically connected with each other through conductor layer CL4. As a result, electrode EL1, conductor layer CL3, electrode EL2 and conductor layer CL4 constitute coil CO. Axis AX of coil CO (
Wiring for signal input/output (not shown) electrically connected with coil CO is formed in each of semiconductor chips ST1-ST3. Signal transmission between each of semiconductor chips ST1-ST3 and coil CO is carried out through these wirings.
Each of electrodes EL1-EL4 of the present embodiment is formed, for example, as set forth below. First, a through hole is formed using a laser drill at a position where electrodes EL1-EL4 are to be formed in each of semiconductor chips ST1-ST3. A bump of Au, for example, is inserted in the through holes. Then, semiconductor chips ST1-ST3 are stacked, and subjected to pressure from the topmost side. Accordingly, the Au bumps are bonded with each other to constitute electrodes EL1-EL4.
According to package-on-package PP of the present embodiment, advantages similar to those of the package-on-package of the first embodiment can be achieved.
In addition, according to package-on-package PP of the present embodiment, semiconductor package SP4 has a plurality of stacked semiconductor chips ST1-ST3. Each of semiconductor chips ST1-ST3 is electrically connected with each other by electrodes EL1 and EL3 penetrating each of semiconductor chips ST1-ST3 in accordance with normal line NL. At least a portion of coil CO is configured by electrodes EL1 and EL3. Accordingly, a portion of the coil can be established simultaneous to the step of stacking the semiconductor chips. Therefore, the mounting cost and mounting time can be reduced.
The present embodiment is described based on a configuration in which three semiconductor chips SP1-SP3 are stacked. The number of stacked semiconductor chips is arbitrary. Furthermore, it is required that only at least a portion of coil CO is to be configured by the through electrode, and only one of electrodes EL1 and EL3 may be a through electrode.
Referring particularly to
Further, a conductor layer CL7 is formed in resin substrate RS3. Conductor layer CL7 electrically connects conductor layer CL6 with one solder ball SB3 (connection electrode) of semiconductor package SP3. Accordingly, coil CO1 is further configured by conductor layer CL7 and solder ball SB3. Solder ball SB3 is directly electrically connected with conductor layer CL8 (wiring) of substrate SUB on which semiconductor package SP3 is mounted. Coil CO1 is electrically connected with coil CO2 of another package-on-package PP2 through conductor layer CL8. Package-on-package PP2 takes a mirror symmetrical configuration with package-on-package PP1 about the yz plane. Namely, coil CO2 includes conductor layer CL9, solder ball SB4, through hole THe, solder ball SB5, conductor layer CL10, conductor layer CL11, and solder ball SB6.
The remaining configuration of package-on-package PP1 is similar to that of the package-on-package of the third embodiment. Therefore, corresponding members have the same reference character allotted, and description thereof will not be repeated.
According to package-on-package PP of the present embodiment, advantages similar to those of the package-on-package of the first embodiment can be provided.
In addition, at least a portion of coil CO1 is configured by solder ball SB3 in package-on-package PP1 of the present embodiment. Solder ball SB3 is configured to be directly connected to conductor layer CL8 of substrate SUB, and coil CO1 is electrically connected with coil CO2 of another package-on-package PP2 through conductor layer CL8. Accordingly, the coil of each package-on-package can be connected to increase the number of windings of the coil. Furthermore, using these coils, communication with an external apparatus such as a tester can be carried out.
Referring particularly to
The remaining configuration of package-on-package PP1 is similar to that of the package-on-package of the third embodiment. Therefore, the same members have the same reference characters allotted, and description thereof will not be repeated.
Package-on-package PP of the present embodiment includes semiconductor package SP3, semiconductor package SP1, and coil CO. Semiconductor package SP1 is mounted above semiconductor package SP3, and includes solder bumps SB1a and SB1b electrically connected with semiconductor package SP3. Coil CO has at least a portion provided at semiconductor package SP3. Coil CO has at least a portion configured by solder bumps SB1a and SB1b.
According to package-on-package PP of the present embodiment, the mechanical work of winding a coil can be dispensed with since at least a portion of coil CO is configured by solder balls SB1a and SB1b. The cost and time for mounting a coil can be reduced. Furthermore, by establishing a coil spanning between a plurality of semiconductor packages, the number of coil windings can be increased to form an intensive coil.
Furthermore, since at least a portion of coil CO is configured by conductor layer CL12 formed in semiconductor package SP1 and conductor layer CL13 formed in semiconductor package SP3, the cost and time required for mounting a coil can be further reduced. In addition, the radius of the coil can be increased, as compared to a coil formed at a semiconductor chip.
In the vicinity of the four corners of semiconductor package SP having a rectangular plane configuration, electrodes EL1-EL4, formed of Au, for example, are provided. Each of electrodes EL1-EL4 penetrates semiconductor chips ST1-ST3. Each of semiconductor chips ST1-ST3 is electrically connected with each other through electrodes EL1-EL4. Furthermore, a conductor layer CL14 is formed in semiconductor chip ST1. A conductor layer CL15 is formed in semiconductor chip ST2. A conductor layer CL16 is formed in semiconductor chip ST3. Each of conductor layers CL14-CL16 is electrically connected with electrode EL1, and has a plane configuration corresponding to the four sides of a rectangular, for example. Namely, conductor layers CL4-CL16 and electrode EL1 constitute coil CO having three loops. By this coil CO, communication in the vertical direction is allowed.
Each of semiconductor chips ST1-ST3 has formed therein a wiring for signal input/output (not shown) electrically connected with coil CO. Signal transmission between each of semiconductor chips ST1-ST3 and coil CO is carried out through these wirings.
According to package-on-package PP of the present embodiment, advantages similar to those of the package-on-package of the sixth embodiment can be achieved.
In addition, according to package-on-package PP of the present embodiment, semiconductor package SP4 includes a plurality of stacked semiconductor chips ST1-ST3. Each of semiconductor chips ST1-ST3 is electrically connected with each other by electrodes EL1 and EL3 penetrating each of semiconductor chips ST1-ST3 in accordance with normal line NL. At least a portion of coil CO is configured by electrode EL1. Accordingly, a portion of the coil can be established simultaneous to the step of stacking semiconductor chips, allowing the mounting cost and mounting time to be reduced.
In the present embodiment, a configuration in which three semiconductor chips SP1-SP3 are stacked has been described. The number of stacked semiconductor chips is arbitrary. Furthermore, it is required that only at least a portion of coil CO is to be configured by the through electrode, and only one of electrodes EL1 and EL3 may be a through electrode.
In the present invention, the semiconductor device may include two or more coils. Accordingly, one coil may be directed to transmission and the other coil directed to reception. The number and layout of the semiconductor packages, the number and layout of the semiconductor chips, the number and layout of the solder balls, and the number of windings of the coil are arbitrary. Furthermore, the connection electrode is at least an electrode of the semiconductor package, and may be a conductor other than a solder bump such as a carbon nanotube.
Further, the present invention is applicable to a semiconductor package of large thickness, or an SIP (System In Package), in addition to the package-on-package set forth above. Particularly, since a package-on-package often has a thickness of several mm in the direction of the height (direction of the z axis), a coil can be readily formed by taking advantage of this thickness.
Furthermore, the configuration described above in the first to seventh embodiments can be combined appropriately.
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
The present invention is suitable as a semiconductor device mounted on a portable apparatus requiring low power. The present invention is also suitable to a product that can be readily accommodated by exchanging the semiconductor device. Furthermore, since communication is allowed without having to use a metal contact, the present invention is suitable as a semiconductor device mounted on a product that requires waterproof features such as a digital camera directed to an underwater camera.
AX axis; CL1-CL16 conductor layer; CO, CO1, CO2 coil; DB delay buffer; EL1-EL4 electrode; FF storage element; INV1 reception buffer; INV2, INV3 transmission buffer; L1 transmission coil; L2 reception coil; LD, LDa, LDb land; LS semiconductor package bottom face; MR, MR1-MR3 mold resin; NAND1, NAND2 NAND circuit; NL normal line of semiconductor package bottom face; PP, PP1, PP2 package-on-package; R1 resistor; RS1-RS4 resin substrate; Rxclk reception clock; Rxdata reception data; SB1, SB1a-SB1c, SB2, SB2a-SB2c, SB3-SB6 solder ball; SP, SP1-SP4 semiconductor chip; SR3 solder resist; ST1-ST3 semiconductor chip; SUB substrate; T1-T10 transistor; THa-THf through hole; Txclk transmission clock, Txdata transmission data; Vbias bias voltage.
Number | Date | Country | Kind |
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2008-239211 | Sep 2008 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2009/062099 | 7/2/2009 | WO | 00 | 5/31/2011 |