Abstract:
A semiconductor device includes a substrate having a main surface and a rear surface, a transistor formed over a side of the main surface, an insulator layer formed over a side of the main surface, an inductor formed over the insulator layer and a side of the main surface, a tape overlapping the inductor and formed over a side of the main surface, and a bonding pad formed over the insulating layer and a side of the main surface. The tape is selectively formed over an area without the bonding pad.

Description:
[0001]    The present application is a Continuation Application of U.S. patent application Ser. No. 13/064,941, filed on Apr. 27, 2011, which is a Continuation Application of U.S. patent application Ser. No. 12/591,983, now U.S. Pat. No. 7,935,549, which are based on and claim priority from Japanese patent application No. 2008-313316, filed on Dec. 9, 2008, the entire contents of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a signal transmitting/receiving method, a semiconductor device manufacturing method, a semiconductor device, and a tester. 
         [0003]    In order to test an internal circuit of the semiconductor device in its wafer state, there have been attempts to probe a pad on a chip surface of the semiconductor device for supplying an electric power or to transmit and receive signals for observation. Such techniques have been disclosed in the following Patent Documents. 
         [0004]    Japanese Patent Laid-Open No. 2005-30877 discloses a technique for performing a test by mounting a test circuit and a wireless communication circuit in a semiconductor integrated circuit device, and using wireless signals to control the test circuit. 
         [0005]    Japanese Patent Laid-Open No. 2003-344448 discloses a voltage probe chip having a sensor electrode which is disposed facing a signal line to be monitored on a semiconductor chip so as to detect a voltage change of the signal line as an induced voltage caused by electrostatic induction. 
         [0006]    However, the inventors have found the following problems. There are problems in that the pad is damaged by a tester needle during a probe test, causing a connection failure later when the pad is bonded, or the pad is scratched to generate scrap materials causing contamination, and the like. There is another problem in that the more the chip size is reduced and the more the number of pads per chip is increased, the more the pad size and the inter-pad pitch is reduced, and thereby the more difficult it is to provide a well electrical connection by contacting a large number of probe needles corresponding to a large number of pads. In order to prevent such problems, it is preferable to transmit and receive signals to and from the internal circuit without using the probe needles. 
         [0007]    However, in order to obtain signals having intensity enough to transmit and receive the signals by electromagnetic induction using an inductor, it is necessary to increase the inductor size, which increases the area necessary to provide the inductors. In particular, in order to provide a large number of inductors corresponding to a large number of pads, the area necessary to provide the inductors is greatly increased. 
       SUMMARY 
       [0008]    The present invention provides a signal transmitting/receiving method comprising: disposing a ferromagnetic film between a semiconductor device having an inductor and an external device which includes an external inductor provided in a position corresponding to the inductor of the semiconductor device; disposing the inductor and the external inductor so as to face each other via the ferromagnetic film therebetween; and in a state in which the inductor and the external inductor face each other, transmitting and receiving the signals between the inductor and the external inductor by electromagnetic induction. 
         [0009]    Further, the present invention provides a semiconductor device manufacturing method comprising: disposing a semiconductor device which includes a first insulating film which includes a transistor on a substrate and a second insulating film which is provided on the first insulating film and includes an inductor and an external device which includes an external inductor provided in a position corresponding to the inductor of the semiconductor device so as to face each other; and disposing a ferromagnetic film which includes ferromagnetic fine particles at least between the inductor of the semiconductor device and the external inductor of the external device; and disposing the inductor and the external inductor so as to face each other via the ferromagnetic film therebetween; and in a state in which the inductor and the external inductor are made to face each other, transmitting and receiving signals between the inductor and the external inductor by electromagnetic induction. 
         [0010]    This configuration can maintain as small an area as necessary to provide the inductors and can well transmit and receive signals by electromagnetic induction. 
         [0011]    The above configuration can increase the inductor coupling factor between the inductors formed in the semiconductor device and the external inductors when signals are transmitted and received therebetween by electromagnetic induction. Thereby, this configuration allows an inductor with a smaller size to well transmit and receive signals by electromagnetic induction. For this reason, this configuration can maintain as small an area as necessary to provide the inductors and can well transmit and receive signals by electromagnetic induction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above and other objects, advantages and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
           [0013]      FIGS. 1A to 1C  each is a process cross-sectional view illustrating a procedure for manufacturing a semiconductor device in accordance with an embodiment of the present invention; 
           [0014]      FIGS. 2A to 2D  each is a process cross-sectional view illustrating a procedure for manufacturing a semiconductor device in accordance with an embodiment of the present invention; 
           [0015]      FIG. 3  is a plan view of the substrate illustrated in  FIG. 1 ; 
           [0016]      FIG. 4  is an enlarged view of  FIG. 3 ; 
           [0017]      FIG. 5  is an enlarged sectional view of  FIG. 2A ; 
           [0018]      FIG. 6  is an enlarged sectional view of  FIG. 2B ; 
           [0019]      FIG. 7  is a plan view illustrating an example of a semiconductor chip forming region of the semiconductor device in accordance with an embodiment of the present invention; 
           [0020]      FIG. 8  is a plan view illustrating another example of the semiconductor chip forming region of the semiconductor device in accordance with an embodiment of the present invention; 
           [0021]      FIG. 9  is a sectional view illustrating a configuration of a tester in accordance with an embodiment of the present invention; and 
           [0022]      FIG. 10  is a sectional view illustrating another example of the semiconductor device in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0023]    The invention will be now described herein with reference to illustrative embodiments. Those skilled in the art will recognize that many alternative embodiments can be accomplished using the teachings of the present invention and that the invention is not limited to the embodiments illustrated for explanatory purposes. 
       First Embodiment 
       [0024]    Hereinafter, embodiments of the present invention will be described by referring to drawings. Note that throughout the drawings, like reference characters refer to like elements and the duplicate description is omitted as needed. In the present embodiment, assuming that the external device is a tester, the following description will use an example in which when a test is conducted on an internal circuit in a chip forming region of the semiconductor device in its wafer state, various test signals are transmitted and received to and from the tester by electromagnetic induction. 
         [0025]      FIGS. 1 and 2  each is a process cross-sectional view illustrating a procedure for manufacturing a semiconductor device in accordance with an embodiment of the present invention. 
         [0026]    The semiconductor device  100  includes a substrate  102  (wafer). According to the present embodiment, an inductor forming region  110  in which a plurality of inductors are formed is provided on one surface of the substrate  102 . Signals are transmitted and received between the above configured semiconductor device  100  and a tester  200  which includes a plurality of external inductors each of which is provided in a position corresponding to each inductor in the semiconductor device  100 , and transmits and receives the signals by electromagnetic induction. 
         [0027]      FIG. 3  is a plan view of the substrate  102  illustrated in  FIG. 1 .  FIG. 4  is an enlarged view of  FIG. 3 .  FIG. 3  illustrates only the outer edge of the substrate  102 . As illustrated in  FIG. 4 , the one surface of the substrate  102  includes a plurality of semiconductor chip forming regions  104  and scribe line regions  106  each of which is provided on the outer circumference of a semiconductor chip forming region  104 .  FIG. 4  illustrates four semiconductor chip forming regions  104  and an alignment mark  108  between them in the scribe line region  106 . The semiconductor chip forming region  104  is a region which will be a semiconductor chip after dicing. 
         [0028]    An internal circuit  118 , a plurality of inductors  114 , and a plurality of bonding pads  116  are provided in each semiconductor chip forming region  104  of the semiconductor device  100 . The bonding pad  116  is a pad on which wire bonding is performed later. The bonding pad  116  is wire-connected to the internal circuit  118 , the wire of which is connected to the inductors  114 . The inductor  114  can be provided as an alternative to the pad provided for probing when a test is performed on an internal circuit of a conventional semiconductor device in its wafer level. The inductor  114  may be provided or may not be provided in all the wires connecting between the bonding pad  116  and the internal circuit  118 . In addition, although not illustrated, the semiconductor device  100  includes a plurality of conversion circuits provided corresponding to each inductor  114 . Moreover, although not illustrated, the semiconductor device  100  can include a power circuit. 
         [0029]    Note that the inductors  114  are provided on the surface of the semiconductor device  100  so as to transmit and receive signals to and from an external device. In addition, the bonding pads  116  are also provided on the surface of the semiconductor device  100  so as to perform wire bonding later. Note that the surface of the inductor  114  may be covered with a film such as a passivation film to such an extent that the film does not affect the process of transmitting and receiving signals by electromagnetic induction. Moreover, the bonding pad  116  is formed in a region not to interrupt communication between the inductors  114  and the external device. Here, the region not to interrupt communication indicates a case in which the inductor  114  and the bonding pad  116  are formed in a different region when viewed from above in  FIG. 4 . Note that the inductor  114  and the bonding pad  116  shall be slightly overlapped. 
         [0030]    On the other hand, the conversion circuit serves only to convert the signals that the inductors  114  transmit and receive to and from the external device, and thus needs not be provided on the surface of the semiconductor device  100 . For this reason, the conversion circuits can be provided so as to be overlapped with the inductors  114  in the laminating direction of the semiconductor substrate, and thus can suppress an increase in size of the semiconductor device  100 . For example, each conversion circuit is provided in a layer under its corresponding inductor  114 . Each inductor  114  is electrically connected to the internal circuit  118  via its corresponding conversion circuit. The conversion circuit performs modulation and demodulation on the signals transmitted and received between the internal circuit  118  and the external device. In addition, each bonding pad  116  is also electrically connected to the internal circuit  118 . 
         [0031]    Although not illustrated here, the internal circuit  118  can include a plurality of transistors corresponding to the plurality of inductors  114 . One end of each of the source and the drain of a transistor is connected to ground and the other end thereof is connected to a power circuit via a power supply line. In addition, the gate of each transistor is connected to each inductor  114  via each conversion circuit. Further, the gate of each transistor is also connected to each bonding pad  116 . Note that a configuration may be made such that an I/O buffer circuit is included between the transistor, the bonding pad  116 , and the conversion circuit. 
         [0032]    Now, going back to  FIGS. 1 and 2 , the description continues with the procedure for manufacturing the semiconductor device in accordance with the present embodiment. 
         [0033]    As illustrated in  FIG. 1A , the ferromagnetic film  130  is formed on the inductor forming region  110  formed on one surface of the substrate  102  of the semiconductor device  100  described above. The ferromagnetic film  130  can be a tape containing ferromagnetic fine particles in an insulating film (polymer) such as polyester. Here, the ferromagnet can be a metal such as Fe, Co, and Ni or their alloy. The ferromagnetic film  130  can be about as thick as from 20 μm to 0.25 mm. The ferromagnetic film  130  can be formed on the semiconductor device  100 , for example, in the following procedure. First, an adhesive such as a water-soluble glue is applied to the entire surface of the ferromagnetic film  130 , and the ferromagnetic film  130  is disposed in such a manner that the one surface on which the adhesive is applied is in contact with the one surface of the substrate  102  on which the inductor forming region  110  is formed. Then, the ferromagnetic film  130  is pressed and adhered onto the inductor forming region  110  by a roller (not illustrated) or the like. 
         [0034]    Then, for example, the ferromagnetic film  130  is cut along the circumferential portion of the substrate  102  by contacting the cutter  150 , which is a circumferential cutter, against the edge of the substrate  102 . Thereby, the ferromagnetic film  130  having the same size of the substrate  102  can be formed on the substrate  102  ( FIG. 1B ). 
         [0035]    Next, the bottom surface opposite to the one surface of the substrate  102  is ground by a machine such as a back grinder to form the substrate  102  having a predetermined thickness. For example, the thickness of the substrate  102  can be about from 200 μm to 400 μm ( FIG. 1C ). 
         [0036]    Subsequently, signals are transmitted and received between external inductors of the tester  200  and inductors in the inductor forming region  110  of the semiconductor device  100 . According to the present embodiment, the tester  200  includes a plurality of test chips  201  (chips for performing a test). Each test chip  201  is formed to a size corresponding to each semiconductor chip forming region  104  of the semiconductor device  100 . 
         [0037]    First, the semiconductor device  100  is mounted on a mounting base  152 , and the tester  200  is placed closer to the semiconductor device  100 . Then, signals are transmitted and received between the external inductors of the tester  200  and the inductors in the inductor forming region  110  of the semiconductor device  100  ( FIG. 2A  and  FIG. 2B ). 
         [0038]      FIG. 5  and  FIG. 6  each is an enlarged sectional view of  FIG. 2A  and  FIG. 2B  respectively. Here, each figure partially illustrates one of the semiconductor chip forming region  104  (see  FIG. 4 ) of the semiconductor device  100  and one of the test chips  201  of the tester  200 . 
         [0039]    The inductor forming region  110  of the semiconductor device  100  has an insulating film  112  provided on the substrate  102  and a plurality of inductors  114  provided on one surface of the insulating film  112  opposite to a surface facing the substrate  102 . In addition, although not illustrated, the bonding pads  116  are also provided on one surface of the insulating film  112 . That is, according to the present embodiment, the ferromagnetic film  130  is also provided on the bonding pads  116 . The test chip  201  of the tester  200  includes a test substrate  202  and a plurality of external inductors  204  each provided in a position corresponding to the plurality of inductors  114  of the semiconductor device  100 . 
         [0040]    Here, the insulating film  112  includes an insulating layer  165  which includes transistors  168  constituting circuits such as an internal circuit, a conversion circuit, and a power circuit; and an insulating layer  166  which mainly includes wires. Both insulating layers  165  and  166  may be formed of a plurality of insulating films and each insulating layer has wires required for circuit configuration therein. The inductor  114  is formed in the uppermost surface layer of the insulating layer  166 ; and the bonding pad  116  is formed in the uppermost surface layer of the insulating layer  166  or on the insulating layer  166 , for example. 
         [0041]    First, the tester  200  is placed closer to the semiconductor device  100  in such a manner that each external inductor  204  of the tester  200  faces each inductor  114  of the semiconductor device  100 . At this time, the ferromagnetic film  130  is disposed between each inductor  114  of the semiconductor device  100  and each external inductor  204  of the tester  200 ; and each inductor  114  and each external inductor  204  are disposed facing each other via the ferromagnetic film  130  therebetween. Moreover, here, each inductor  114  and each external inductor  204  can be disposed facing each other in contact with the ferromagnetic film  130 . Here, the ferromagnetic film  130  can also be made to function as a cushioning material. Moreover, the ferromagnetic film  130  can be configured to have an approximately equal film thickness entirely. By doing so, each inductor  114  and each external inductor  204  can be stably spaced at constant intervals. 
         [0042]    In this state, a radio wave having a predetermined frequency is outputted from each external inductor  204  of the tester  200  to the semiconductor device  100 . Here, a test signal and the like are outputted from the external inductor  204 . 
         [0043]    The inductor  114  of the semiconductor device  100  converts the signal outputted from the external inductor  204  to an AC electrical signal. The conversion circuit demodulates the AC electrical signal converted by the inductor  114  and supplies it to the internal circuit  118 . On the other hand, when a signal is outputted from the semiconductor device  100  to the tester  200 , the conversion circuit modulates the electrical signal supplied from the internal circuit  118  and supplies it to the inductor  114 . The inductor  114  outputs the modulated signal as a radio wave to the corresponding external inductor  204  of the tester  200 . In this manner, signals are transmitted and received between the semiconductor device  100  and the tester  200 . 
         [0044]    After the process of transmitting and receiving signals between the semiconductor device  100  and the tester  200  is completed, the ferromagnetic film  130  is removed. The process of removing the ferromagnetic film  130  can be performed in the following procedure. First, in a tape peeling device (not illustrated), the substrate  102  of the semiconductor device  100  is fixed by a vacuum chuck. In this state, a peeling tape  140  is placed in contact on the ferromagnetic film  130  so as to peel the ferromagnetic film  130  ( FIG. 2C ). Then, the peeling tape  140  is peeled off from the semiconductor device  100  together with the ferromagnetic film  130  ( FIG. 2D ). Subsequently, pure water, an organic solvent, or the like is used to clean the semiconductor device  100  and dry it. Thus, the above process completes the wafer test. 
         [0045]    Subsequently, for example, the semiconductor device  100  is cut along the scribe line region  106  to make each semiconductor chip forming region  104  into a chip. Then, a semiconductor chip can be formed by connecting each bonding pad  116  of the each semiconductor chip forming region  104  to an external terminal with a bonding wire, or the like. 
         [0046]    According to the present embodiment, when signals are transmitted and received between the external inductors  204  of the tester  200  and the inductors  114  of the semiconductor device  100  by electromagnetic induction, the bonding pad is provided in a region not to interrupt the communication to and from the external device, and thus can increase the inductor coupling factor therebetween. The inductor coupling factor can further increase by placing the ferromagnetic film  130  between the external inductors  204  and the inductors  114  of the semiconductor device  100 . Thereby, this configuration allows an inductor with a smaller size to well transmit and receive signals by electromagnetic induction. For this reason, this configuration can maintain as small an area as necessary to provide the inductors and can well transmit and receive signals by electromagnetic induction. 
         [0047]    Moreover, the ferromagnetic film  130  can also be made to function as a cushioning material. Therefore, the external inductors  204  of the tester  200  and the inductors  114  of the semiconductor device  100  can be placed in contact with the ferromagnetic film  130 . By doing so, each inductor  114  and each external inductor  204  can be stably spaced at constant intervals. 
       Second Embodiment 
       [0048]    According to the present embodiment, a configuration may be made in such a manner that after the process of transmitting and receiving the signals is completed, the ferromagnetic film  130  remains partially on the semiconductor device  100 . 
         [0049]      FIG. 7  is a plan view illustrating an example of the semiconductor chip forming region  104  (see  FIG. 4 ) of the semiconductor device  100  in accordance with the present embodiment. In this example, the ferromagnetic film  130  is not formed selectively only on a region of the semiconductor device  100  where the bonding pads  116  are formed. For example, the ferromagnetic film  130  can be configured to have an opening portion  132  so as to expose the bonding pads  116 . By doing so, each bonding pad  116  can be connected to an external terminal with a bonding wire with the ferromagnetic film  130  left as is. 
         [0050]    Thus configured ferromagnetic film  130  can be obtained in such a manner that for example, after the ferromagnetic film  130  is formed on the entire surface of the semiconductor device  100 , the ferromagnetic film  130  is removed selectively to form the opening portion  132 . The selective removal of the ferromagnetic film  130  can be performed, for example, by wet etching using photoresist as a mask. Here, for example, the ferromagnetic film  130  can be formed in such a manner that after a multi-layered structure of the semiconductor device is formed, a ferromagnet is mixed into a passivation film formed on the upper surface thereof. In this case, the selective removal of the ferromagnetic film  130  can be performed, for example, by wet etching using photoresist as a mask. The selective removal of the ferromagnetic film  130  may be performed either before or after signals are transmitted and received between the external inductors  204  of the tester  200  and the inductors  114  of the semiconductor device  100 . 
         [0051]      FIG. 8  is a plan view illustrating another example of the semiconductor chip forming region  104  (see  FIG. 4 ) of the semiconductor device  100  in accordance with the present embodiment. In this example, the ferromagnetic film  130  is formed selectively only on a region of the semiconductor device  100  where the inductors  114  are formed. Note that here, for the purpose of the description, the inductors  114  are also illustrated, but actually the inductors  114  are covered with the ferromagnetic film  130 . Such a configuration also allows the bonding pads  116  to be exposed, and thus each bonding pad  116  can be connected to an external terminal with a bonding wire with the ferromagnetic film  130  left as is. 
         [0052]    Thus configured ferromagnetic film  130  can be obtained in such a manner that for example, after the ferromagnetic film  130  is formed on the entire surface of the semiconductor device  100 , the ferromagnetic film  130  is removed selectively. In this case, the selective removal of the ferromagnetic film  130  can also be performed, for example, by wet etching using photoresist as a mask. Here, for example, the ferromagnetic film  130  can be formed in such a manner that after a multi-layered structure of the semiconductor device is formed, a ferromagnet is mixed into a passivation film formed on the upper surface thereof. In this case, the selective removal of the ferromagnetic film  130  can also be performed, for example, by wet etching using photoresist as a mask. The selective removal of the ferromagnetic film  130  may be performed either before or after signals are transmitted and received between the external inductors  204  of the tester  200  and the inductors  114  of the semiconductor device  100 . 
         [0053]    The present embodiment can also provide the same effect as the first embodiment. 
       Third Embodiment 
       [0054]    According to the present embodiment, the ferromagnetic film  130  can be configured to be provided on the tester  200  side. 
         [0055]      FIG. 9  is a sectional view illustrating a configuration of the tester  200  in accordance with present embodiment. Here, the tester  200  includes the ferromagnetic film  130  formed on the surface of the external inductors  204 . Such a configuration can also provide the same effect as the first embodiment and the second embodiment. Alternatively, a configuration may be made such that two ferromagnetic films  130  are provided one on the tester  200  side and one on the semiconductor device  100  side. 
         [0056]    Hereinbefore, the embodiments of the present invention have been described by referring to drawings, but these embodiments are examples of the present invention and various configurations other than the above can be adopted. 
         [0057]    In the above embodiments, the procedure for grinding the bottom surface of the substrate  102  described by referring to  FIG. 1C  may be omitted.  FIG. 10  is a sectional view illustrating the semiconductor device  100  corresponding to  FIG. 2B  in this case. In this case, like the one illustrated in  FIG. 2 , signals can also be transmitted and received between the semiconductor device  100  and the tester  200 . 
         [0058]    Further, the above embodiments have illustrated the example in which the tester  200  has a plurality of test chips  201  corresponding to the number of semiconductor chip forming regions  104  of the semiconductor device  100 , but the tester  200  may be configured to include the number of test chips  201  corresponding to only a part of the semiconductor chip forming regions  104  of the semiconductor device  100 . In this case, a test can be performed in series on each semiconductor chip forming region  104  of the semiconductor device  100  by shifting the tester  200 . 
         [0059]    Moreover, the above embodiments have illustrated the example in which the test is performed on the internal circuit of the chip forming region of the semiconductor device in its wafer state. However, the present invention can be applied to an example in which after the chip forming region is cut into a chip, a test is performed on the internal circuit for each semiconductor chip. 
         [0060]    Further, the ferromagnetic film  130  can be used as an independent sheet without being formed on the semiconductor device  100  or on the tester  200 . In this case, when signals are transmitted and received between the semiconductor device  100  and the tester  200  by electromagnetic induction, the ferromagnetic film  130  can be disposed between the inductors  114  of the semiconductor device  100  and the external inductors  204  of the tester  200 . 
         [0061]    It is apparent that the present invention is not limited to the above embodiments and descriptions, but may be modified and changed without departing from the scopes and sprits.