Abstract:
The invention is directed to a system and method comprising a first semiconductor device and a second semiconductor device, wherein the first semiconductor device comprises a voltage supply means, characterized in that the voltage supply means of the first semiconductor device is connected to the second semiconductor device, so that the voltage supply means of the first semiconductor device can provide a supply voltage for the second semiconductor device.

Description:
This application claims priority to German Patent Application DE 10315303.9, which was filed Apr. 2, 2003. 
     TECHNICAL FIELD 
     The invention relates to a system with two—especially stacked—semiconductor devices and a semiconductor device voltage supply for such a system, respectively. 
     BACKGROUND 
     Semiconductor devices, in particular memory devices such as DRAMS (DRAM=Dynamic Random Access Memory or dynamic read-write-memory, respectively) in general comprise one or several voltage supply means. 
     A voltage supply means serves to generate, from an—externally provided—voltage, a voltage used internally in the semiconductor device. 
     The voltage level of the internal voltage generated by the semiconductor device voltage supply means may differ from the level of the external voltage. 
     In particular, the internally used voltage level may be lower than the externally used voltage level. 
     An internal voltage level that is reduced vis-à-vis the externally used voltage level has, for instance, the advantage that the power loss in the semiconductor device can be reduced. 
     Furthermore, the external voltage may be subject to relatively strong fluctuations. Therefore, a so-called voltage regulator is frequently used as voltage supply means, which—in order that the device may be operated without fault—converts the external voltage into an internal voltage that is subject to relatively minor fluctuations only and is regulated at a particular, constant (possibly reduced) value. 
     Conventional voltage regulators may, for instance, comprise a differential amplifier and a field effect transistor. The gate of the field effect transistor may be connected to an output of the differential amplifier, and the source of the field effect transistor may e.g. be connected to the external voltage. 
     A reference voltage—which is subject to relatively minor fluctuations only—is applied to the positive input of the differential amplifier. The voltage output at the drain of the field effect transistor may be fed back to the negative input of the differential amplifier directly, or e.g. by the interposition of a voltage divider. 
     The differential amplifier regulates the voltage available at the gate connection of the field effect transistor such that the (fed back) drain voltage—and thus the voltage output by the voltage regulator—is constant and as high as the reference voltage, or e.g. by a certain factor higher. 
     Semiconductor devices are usually incorporated in appropriate housings, e.g. appropriate surface mountable housings (SMD housings) or plug mountable housings (e.g. corresponding Dual-In-Line (DIL) housings, Pin-Grid-Array (PGA) housings, etc.). 
     In one single housing, there may also be arranged two or more semiconductor devices instead of only one single semiconductor device. 
     In the case of memory devices, in particular DRAMs for increasing the storage density, several semiconductor devices may, for instance, be mounted in a stacked manner in one single housing. 
     For instance, two 256 Mbit memory devices may be provided in one single housing, this effecting a 512 Mbit chip. 
     The semiconductor devices, in particular memory devices, provided in one single housing comprise voltage supply means that are independent of one another. 
     When a memory device is accessed (i.e. when corresponding external data are stored on the memory device, or when data that are stored on the memory device are read out), there will flow, in general, relatively high currents that are generated by the corresponding voltage supply means. 
     Contrary to this, only relatively low currents will flow in standby or refresh operaation (e.g. for supplying leakage currents or operating currents). 
     The standby or refresh currents each may, for instance, be in the range of apporx. 50 μA—i.e. amount to a total of 100 μA in the case of e.g. two stacked memory devices (with the operating currents of the respective voltage supply means constituting the major part of these currents). 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a novel system with two—especially stacked—semiconductor devices, and—in particular—a semiconductor device voltage supply for such a system, respectively. 
     The invention achieves this and further objects by the subject matter of claim  1 . 
     Advantageous further developments of the invention are indicated in the subclaims. 
     In accordance with a basic idea of the invention, a system, in particular a semiconductor device system, is provided, comprising
         a first semiconductor device, and   a second semiconductor device,       

     wherein the first semiconductor device comprises a voltage supply means, and wherein the voltage supply means of the first semiconductor device is connected to the second semiconductor device, so that the voltage supply means of the first semiconductor device can provide a supply voltage for the second semiconductor device. 
     It is of particular advantage when the second semiconductor device additionally also comprises a voltage supply means. 
     Preferably, in a first operating mode of the second semiconductor device, the voltage supply means of the second semiconductor device provides the voltage supply for the second semiconductor device, and in a second operating mode of the second semiconductor device—in particular in a standby or refresh mode—, this is effected by the voltage supply means of the first semiconductor device. 
     The voltage supply means of the second semiconductor device may then be deactivated, so that the operating current thereof may be saved (and thus, altogether, the currents required for operating the semiconductor devices). 
     In an advantageous development of the invention, the first semiconductor device and the second semiconductor device are arranged in one and the same housing. 
     Preferably, the first and second semiconductor devices are arranged in the housing in a stacked manner. 
     Advantageously, the housing may be a plug mountable semiconductor device housing, or e.g. a surface mountable semiconductor device housing. 
     It is particularly preferred when the first and/or the second semiconductor devices are corresponding memory devices, in particular corresponding DRAM memory devices. 
     In an advantageous development of the invention, the voltage supply means of the first semiconductor device is connected to a corresponding pad of the first semiconductor device. 
     Preferably, the pad of the first semiconductor device is connected to a corresponding pad of the second semiconductor device, which the voltage supply means of the second semiconductor device can be connected to. 
     The pad of the first semiconductor device may, for instance, be connected directly to the corresponding pad of the second semiconductor device, in particular by means of an appropriate bonding wire. 
     Alternatively, the pad of the first semiconductor device may, for instance, also be connected to the corresponding pad of the second semiconductor device indirectly, e.g. via an interposer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following, the invention will be explained in detail by means of several embodiments and the enclosed drawing. The drawing shows: 
         FIG. 1   a  is a schematic representation of a system with two stacked semiconductor devices with a semiconductor device voltage supply in accordance with a first embodiment of the present invention; and 
         FIG. 1   b  is a schematic representation of a system with two stacked semiconductor devices with a semiconductor device voltage supply in accordance with a second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     List of Reference Signs
           1  semiconductor device system     2   a  semiconductor device     2   b  semiconductor device     3   a  voltage supply means     3   b  voltage supply means     4  semiconductor device housing     5   a  semiconductor device pad     5   b  semiconductor device pad     5   c  semiconductor device pad     5   d  semiconductor device pad     6  bonding wire     6   a  bonding wire     6   b  bonding wire     7   a  line     7   b  line     7   c  line     7   d  line     8  activating/deactivating control means     9  interposer     10  connection       

       FIG. 1   a  is a schematic representation of a system  1  with two stacked semiconductor devices  2   a ,  2   b  in accordance with a first embodiment of the present invention. 
     The two semiconductor devices  2   a ,  2   b  are—apart, in particular, from the components serving for voltage supply of the semiconductor devices  2   a ,  2   b  or controlling the voltage supply, respectively, which will be explained in more detail in the following—substantially of identical structure. 
     The semiconductor devices  2   a ,  2   b  may, on principle, be any type of logic and/or memory devices, e.g. functional memory devices, in particular programmable logic devices (PLDs) or programmable logic arrays (PLAs), or e.g. table memory devices, in particular ROM or RAM table memory devices, etc. 
     For instance, appropriate DRAM table memory devices, e.g. a 256 Mbit, a 512 Mbit, or a 1 Gbit DRAM table memory device  2   a ,  2   b , for instance appropriate DDR-DRAMs (Double Data Rate DRAMs), may be used as semiconductor devices  2   a ,  2   b.    
     As is illustrated schematically in  FIG. 1   a , the semiconductor devices  2   a ,  2   b  are arranged in the same semiconductor device housing  4 . 
     The housing  4  may, for instance, be an appropriate plug mountable semiconductor device housing, e.g. a Dual-In-Line (DIL) housing, a Pin-Grid-Array (PGA) housing, etc., or a surface mountable semiconductor device housing (SMD housing), etc. 
     As results further from  FIG. 1   a , the semiconductor devices  2   a ,  2   b  are mounted in the housing  4  such that they are substantially stacked. 
     By the stacking of the semiconductor devices  2   a ,  2   b  in the same housing  4 , the system  1  can—e.g. when two 256 Mbit memory devices  2   a ,  2   b  are used as semiconductor devices  2   a ,  2   b —altogether be used as a 512 Mbit memory device (or e.g. when two 512 Mbit memory devices are used, as a 1 Gbit memory device, etc.). 
     As is further illustrated in  FIG. 1   a , each semiconductor device  2   a ,  2   b  comprises a voltage supply means  3   a ,  3   b  having a structure similar to that of conventional voltage supply means (or—alternatively—a plurality of, e.g. two, three, four, five, six, or seven, voltage supply means having a structure corresponding to that of the voltage supply means  3   a ,  3   b ). 
     The voltage supply means  3   a ,  3   b  serve to generate, from an external voltage—provided by a voltage source (not illustrated) arranged externally of the semiconductor devices  2   a ,  2   b  and of the housing, respectively—a corresponding internal voltage—used, for instance, internally in the respective semiconductor device  2   a ,  2   b  (cf. explanations below). 
     The external voltage provided by the external voltage source may, for instance, be supplied to the voltage supply means  3   a ,  3   b  via one or a plurality of supply pins (not illustrated) of the semiconductor device housing  4 , and via semiconductor device pads connected therewith (e.g. the pads  5   c ,  5   d  illustrated in  FIG. 1   a ), as well as via corresponding lines  7   a ,  7   b  connected to the pads  5   c ,  5   d  or extending in the semiconductor devices  2   a ,  2   b , respectively. 
     As voltage supply means  3   a ,  3   b , e.g. appropriate charge pumps may be used that have a structure similar to that of conventional charge pumps, or e.g.—as in the embodiment illustrated here—voltage regulating means  3   a ,  3   b  that have a structure similar to that of conventional voltage regulating means. 
     These means serve to convert the external voltage—which may be subject to relatively strong fluctuations—into the above-mentioned internal voltage—which is subject to relatively minor fluctuations only and is regulated at a particular, constant value. 
     The internal voltage may, for instance, have substantially the same, or alternatively e.g. a lower, voltage level as/than the external voltage. The external voltage may, for instance, lie in the range of between 1.5 V and 2.5 V, e.g. at 1.8 V, and the internal voltage e.g. in the range of between 1.3 V and 2.0 V, e.g. at 1.5 V. 
     The voltage supply means  3   a ,  3   b  or voltage regulating means  3   a ,  3   b , respectively, each may, for instance, comprise a differential amplifier and a field effect transistor. The gate of the field effect transistor may be connected to an output of the differential amplifier, and the source of the field effect transistor may be connected e.g. to the above-mentioned external voltage. 
     A reference voltage that is subject to relatively minor fluctuations only is applied to the positive input of the differential amplifier. The voltage output at the drain of the field effect transistor may be fed back to the negative input of the differential amplifier directly, or e.g. by the interposition of a voltage divider. 
     The differential amplifier regulates the voltage available at the gate connection of the field effect transistor such that the (fed back) drain voltage—and thus the voltage output by the corresponding voltage supply means  3   a ,  3   b  or voltage regulating means  3   a ,  3   b , respectively, e.g. at corresponding lines  7   c ,  7   d  or connections, respectively (i.e. the above-mentioned voltage used internally on the semiconductor devices  2   a ,  2   b  (internal voltage))—is constant and as high as the reference voltage, or e.g. by a certain factor higher. 
     The first and the second semiconductor devices  2   a ,  2   b  are operated in several, different modes. 
     In a first mode (working mode), an external access to the first or second semiconductor device  2   a ,  2   b  may, for instance, be effected (similar as with conventional memory devices). In so doing, corresponding—external—data may, for instance, be stored on the first or second semiconductor device  2   a ,  2   b  (with the data being input e.g. at corresponding pins of the semiconductor device housing  4 ), or data stored on the first or second semiconductor device  2   a ,  2   b  may be read out externally (with the data being output at corresponding pins of the semiconductor device housing  4 ). 
     A second operating mode may, for instance, be a standby mode (similar as with conventional memory devices), or, e.g. a refresh mode (also similar as with conventional memory devices). 
     During a refresh mode (or more exactly: during a refresh operation), the capacitors of the memory cells on which the data stored on the semiconductor devices  2   a ,  2   b  are stored, are correspondingly refreshed. 
     A refresh cycle may be performed at regular time intervals, e.g. every 1 to 10 ms or every 10 to 1000 ms, etc. 
     As will be explained in more detail in the following, in the semiconductor device system  1  illustrated in  FIG. 1   a , the voltage supply means  3   b  of the second semiconductor device  2   b  is activated in the above-mentioned first operating mode (and possibly in one or several further operating mode(s))—e.g. during the above-mentioned working mode—, and in the above-mentioned second operating mode (and possibly in one or several further operating mode(s))—e.g. during the standby mode and/or during the refresh mode—the voltage supply means  3   b  of the second semiconductor device  2   b  is deactivated. 
     This happens e.g. by corresponding activating/deactivating signals being fed to the voltage supply means  3   b  of the second semiconductor device  2   b  by an activating/deactivating control means  8 . 
     In the activated state, the voltage supply means  3   b  of the second semiconductor device  2   b  is switched on (is, in particular, connected to the supply or external voltage, so that corresponding operating currents—e.g. of between 20 μA and 80 μA, e.g. 50 μA—are flowing), and in the deactivated state it is switched off (is, in particular, separated from the supply or external voltage, so that corresponding operating currents are prevented from flowing). 
     As is further illustrated in  FIG. 1   a , the voltage supply means  3   a  of the first semiconductor device  2   a  is connected—here: via the line  7   c —to a corresponding semiconductor device pad  5   a  of the first semiconductor device  2   a.    
     The pad  5   a  is connected to a corresponding semiconductor device pad  5   b  of the second semiconductor device  2   b  by means of a bonding wire  6 . 
     The pad  5   b  of the second semiconductor device  2   b  is connected—here: via the line  7   d —to the voltage supply means  3   b  of the second semiconductor device  2   b  (or to a line or a connection, respectively, at which—in the activated state of the voltage supply means  3   b  of the second semiconductor device  2   b —the internal voltage then generated thereby is output). 
     By the above-described connection of the voltage supply means  3   a  of the first semiconductor device  2   a  to the second semiconductor device  2   b  it is achieved that, in the above-mentioned second operating mode of the second semiconductor device  2   b  (and possibly in one or several further operating mode(s))—e.g. during the standby mode and/or during the refresh mode—, the voltage supply means  3   a  of the first semiconductor device  2   a  can, in addition to the—internal—supply voltage (internal voltage) for the first semiconductor device  2   a , provide the—internal—supply voltage (internal voltage) for the second semiconductor device  2   b.    
     In other words, in the above-mentioned second operating mode the voltage supply means  3   a  of the first semiconductor device  2   a  generates the respectively required (internal) voltages for both semiconductor devices  2   a ,  2   b —the voltage supply means  3   b  of the second semiconductor device  2   b  is deactivated, so that the operating current thereof may be saved (this, altogether, reducing the currents required for operating the semiconductor devices  2   a ,  2   b ). 
     Contrary to this—as has already been explained above—in the above-mentioned first operating mode of the second semiconductor device  2   b  (and possibly in one or several further operating mode(s))—e.g. during the working mode—the voltage supply means  3   b  of the second semiconductor device  2   b  is put to an active state (and the voltage supply means  3   a  of the first semiconductor device  2   a  is possibly additionally separated from the voltage supply means  3   b  of the second semiconductor device  2   b , or the above-mentioned line or the connection, respectively, at which the voltage supply means  3   b  of the second semiconductor device  2   b  outputs the internal voltage generated thereby (e.g. by controlling the activating/deactivating control means  8 , or alternatively e.g. a corresponding control means provided on the first semiconductor device  2   a )). 
     By this it is achieved that, in the above-mentioned first operating mode of the second semiconductor device  2   b  (and possibly in one or several further operating mode(s))—e.g. during the first working mode—the voltage supply means  3   b  of the second semiconductor device  2   b  provides the—internal—supply voltage (internal voltage) for the second semiconductor device  2   b  (and the voltage supply means  3   a  of the first semiconductor device  2   a  the—internal—supply voltage (internal voltage) for the first semiconductor device  2   a ). 
     Advantageously, the first and the second semiconductor devices  2   a ,  2   b  are—in particular until passing through the device function adjusting step which will be explained in more detail in the following—(at first) of substantially identical structure. 
     By means of the device function adjusting step it is determined during the manufacturing of the semiconductor devices whether a corresponding semiconductor device is to fulfill a function that corresponds to the function of the above-mentioned first semiconductor device  2   a , i.e. the function of a “master” which, in the above-mentioned second operating mode (and possibly in one or several further operating mode(s)), is to provide—in addition to its own voltage supply—the respectively required (internal) voltage also for one or several further semiconductor device(s), or a function corresponding to the function of the above-mentioned second semiconductor device  2   b , i.e. the function of a “slave” which is to obtain, in the above-mentioned second operating mode (and possibly in one or several further operating mode(s)) the respectively required (internal) voltage from another semiconductor device (“master”). 
     For determining the function of a corresponding semiconductor device, an appropriate device function adjusting means, in particular an appropriate fuse, may be provided on the semiconductor devices. 
     An appropriate laser fuse or e.g. an appropriate electrical fuse may, for instance, be used as a fuse. 
     When the fuse is shot, the corresponding device assumes e.g. a “master” function, and otherwise a “slave” function (or vice versa). 
     As is shown by means of the alternative embodiment for a semiconductor device system  1  illustrated in  FIG. 1   b , the voltage supply means  3   a  of the first semiconductor device  2   a  may also be connected in any other way than in that illustrated in  FIG. 1   a  to the second semiconductor device  2   b  (or more exactly: the voltage supply means  3   b  of the second semiconductor device  2   b  (or the line or the connection, respectively, at which the voltage supply means  3   b  of the second semiconductor device  2   b  outputs the internal voltage generated thereby in the activated state). 
     For instance, in accordance with  FIG. 1   b , the voltage supply means  3   a  of the first semiconductor device  2   a  may be connected—as described above—to a semiconductor device pad  5   a  of the first semiconductor device  2   a  which—other than with the embodiment illustrated in  FIG. 1   a —is connected to a corresponding contact of an interposer  9  (or to a corresponding leadframe connection  10  of the housing  4 ) by means of a bonding wire  6 . 
     The interposer contact (or the leadframe connection  10 ) is connected to the pad  5   b  of the second semiconductor device  2   b  by means of a further bonding wire  6   b , which is connected to the voltage supply means  3   b  of the second semiconductor device  2   b  (or the above-mentioned line or the connection, respectively, at which—in the activated state of the voltage supply means  3   b  of the second semiconductor device  2   b —the internal voltage then generated thereby is output). 
     By this it can be achieved—similar as with the embodiment illustrated in  FIG. 1   a —that in the second operating mode of the second semiconductor device  2   b  (e.g. during the standby mode and/or during the refresh mode) the voltage supply means  3   a  of the first semiconductor device  2   a  can—in addition to the voltage supply (internal voltage) for the first semiconductor device  2   a —also provide the supply voltage (internal voltage) for the second semiconductor device  2   b.    
     When—corresponding to the first embodiment—the voltage supply means  3   b  of the second semiconductor device  2   b  is correspondingly deactivated in the second operating mode, the operating current of the voltage supply means  3   b  can—corresponding to the embodiment illustrated in  FIG. 1   a —be saved in the above-mentioned second operating mode (and thus, altogether, the currents required for operating the semiconductor devices  2   a ,  2   b ).