Abstract:
An apparatus for checking alignment and an integrated circuit including the same are disclosed. The apparatus includes a center pad, an edge pad configured to surround the center pad and including an opening in at least one side, and a connection wiring configured to pass through the opening and electrically couple the center pad and an internal circuit.

Description:
CROSS-REFERENCES TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. 119(a) to Korean application No. 10-2014-0186141 filed on Dec. 22, 2014, in the Korean intellectual property Office, which is incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    Embodiments of the inventive concept generally relate to an alignment checking apparatus and an integrated circuit including the same, and more particularly to an alignment checking apparatus for checking alignment of a probe pad and an integrated circuit including the same. 
         [0004]    2. Related Art 
         [0005]    A probe card is an apparatus used to test integrated circuits. The probe card includes a printed circuit board (e.g., a multi-layer board) in which circuit patterns for a test process of the integrated circuits are laid out, and a plurality of test needles which are used to make contact with probe pads of the integrated circuits. During the test process of the integrated circuits, test current generated by a tester may be provided to the integrated circuits through the circuit patterns and the needles. The test current may flow to parts of the integrated circuits through the probe pads of the integrated circuits to test electrical characteristics of the integrated circuits. 
         [0006]    A wafer may have alignment checking apparatus thereon to check alignment between the test needles and the probe pads of the integrated circuits. The alignment checking apparatus may include a center pad and, an edge pad surrounding the center pad, and an insulating layer between the center pad and the edge pad. The probe card may detect to which portion of the alignment checking apparatus the test needle is connected so as to ensure accurate test results. 
       SUMMARY 
       [0007]    According to an embodiment, there is provided an apparatus for checking alignment. The apparatus may include a center pad, an edge pad configured to surround the center pad and including an opening in at least one side, and a connection wiring configured to pass through the opening and electrically couple the center pad and an internal circuit. 
         [0008]    According to an embodiment, there is provided a semiconductor integrated circuit device. The semiconductor integrated circuit device may include an apparatus for checking alignment located in a scribe lane of a wafer. The apparatus may include a center pad coupled to a first internal circuit unit through a first connection wiring, and an edge pad configured to surround the center pad, coupled to a second internal circuit unit through a second connection writing, and including at least one opening. The first connection wiring may be configured to pass through the opening. 
         [0009]    These and other features, aspects, and embodiments are described below in the section entitled “DETAILED DESCRIPTION”. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The above and other aspects, features and other advantages of the subject matter of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0011]      FIG. 1  is a schematic plan view illustrating a wafer according to an embodiment of the inventive concept; 
           [0012]      FIG. 2  is an enlarged plan view of a portion “A” of  FIG. 1 ; 
           [0013]      FIG. 3  is a plan view illustrating an alignment checking apparatus according to an embodiment of the inventive concept; 
           [0014]      FIG. 4  is a cross-sectional view illustrating the alignment checking apparatus taken along line IV-IV′ of  FIG. 3 ; 
           [0015]      FIG. 5  is a cross-sectional view illustrating the alignment checking apparatus taken along line V-V′ of  FIG. 3 ; 
           [0016]      FIG. 6  is a plan view illustrating an alignment checking apparatus according to an embodiment of the inventive concept; 
           [0017]      FIG. 7  is an internal circuit diagram illustrating an electrostatic discharge (“ESD”) circuit unit according to an embodiment of the inventive concept; 
           [0018]      FIG. 8  is a plan view illustrating an alignment checking apparatus according to an embodiment of the inventive concept; 
           [0019]      FIG. 9  is a plan view illustrating an alignment checking apparatus according to an embodiment of the inventive concept; and 
           [0020]      FIG. 10  is a plan view illustrating an alignment checking apparatus according to an embodiment of the inventive concept. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    Hereinafter, exemplary embodiments will be described in greater detail with reference to the accompanying drawings. Exemplary embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of exemplary embodiments (and intermediate structures). As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary embodiments should not be construed as limited to the particular shapes of regions illustrated herein but may be to include deviations in shapes that result, for example, from manufacturing. In the drawings, lengths and sizes of layers and regions may be exaggerated for clarity. Like reference numerals in the drawings denote like elements. It is also understood that when a layer is referred to as being “on” another layer or substrate, it can be directly on the other or substrate, or intervening layers may also be present. 
         [0022]    The inventive concept is described herein with reference to cross-section and/or plan illustrations that are schematic illustrations of idealized embodiments of the inventive concept. However, embodiments of the inventive concept should not be limited construed as limited to the inventive concept. Although a few embodiments of the inventive concept will be shown and described, it will be appreciated by those of ordinary skill in the art that changes may be made in these exemplary embodiments without departing from the principles and spirit of the inventive concept. 
         [0023]    Referring to  FIGS. 1 and 2 , an alignment checking apparatus  100  in an embodiment may be located in a scribe lane SL of a wafer W in which general probe pads pb are formed. The scribe lane SL may be a line formed in between two adjacent dies d 1  and d 2  so that die sawing is performed on the scribe lane SL. 
         [0024]    A plurality of test patterns and a plurality of probe pads pb may also be located on the scribe lane SL. The test patterns formed on the scribe lane SL may be removed in a subsequent die sawing process. 
         [0025]    Referring to  FIG. 3 , the alignment checking apparatus  100  in an embodiment may include a center pad  110  and an edge pad  120 . 
         [0026]    The center pad  110  and the edge pad  120  may be formed such that the edge pad  120  surrounds the center pad  110 . The edge pad  120 , which surrounds the center pad  110 , may have a predetermined distance d from the center pad  110 . The edge pad  120  may include at least one opening  125 . The opening  125  may be formed at a side of the edge pad  120 . A first connection wiring  110   a , which is connected to the center pad  110 , may extend through the opening  125  to be electrically coupled to another internal circuit located outside the alignment checking apparatus  100  and receive a certain voltage. For example, the opening  125  may be formed at a side of the edge pad  120  facing the other internal circuit to minimize a length of the first connection wiring  110   a.    
         [0027]    The opening  125  may have a width w 1  greater than a width w 2  of the first connection wiring  110   a.  The first connection wiring  110   a  may extend to the outside of the alignment checking apparatus  100  without contact with the edge pad  120 . An interlayer insulating layer  105  may be located between the edge pad  120  and the center pad  110  when viewed in a plan view. 
         [0028]    When the alignment checking apparatus  100  is electrically coupled to a probe needle  200 , a tester may detect which portion of the alignment checking apparatus  100  the probe needle  200  is in contact with by detecting current flowing through the probe needle  200 , thereby checking an alignment error. 
         [0029]    A second connection wiring  120   a  may also be formed to couple the edge pad  120  and a voltage transfer pad (not shown). The reference numeral  130  denotes a boundary of a passivation layer, which may be used to selectively open the alignment checking apparatus  100 . 
         [0030]    The center pad  110  and the edge pad  120  may be electrically coupled to internal circuits to which certain voltages are provided. For example, the center pad  110  and the edge pad  120  may be electrically coupled voltage transfer pads (not shown). The same voltage may be applied to a voltage transfer pad coupled to the center pad  110  and a voltage transfer pad coupled to the edge pad  120 . Further, voltages having different voltage levels may be applied to the voltage transfer pad coupled to the center pad  110  and the voltage transfer pad coupled to the edge pad  120  as illustrated in  FIG. 6 . 
         [0031]    In case where an edge pad has a closed-loop shape, if a center pad surrounded with the edge pad, a connection wiring, and a voltage transfer pad are on the same plane, it is difficult to couple those things to each other. Thus, the connection wiring coupled to the center pad must be bypassed to a different layer (e.g., a lower layer) to be coupled to the voltage transfer pad, and therefore additional processes such as a contact formation process and an etching process are necessary to couple the center pad, the connection wiring, and the voltage transfer pad to each other. If the connection wiring is bypassed through the lower layer, a length of the connection wiring is increased. 
         [0032]    In an embodiment, the opening  125  is provided in a certain portion of the edge pad  120 , which is formed in an open-loop shape. The center pad  120  may be electrically coupled to the voltage transfer pad on the same plane without a bypass to a lower layer. Therefore, the alignment checking apparatus  100  may be formed without the etching process and contact formation process, which may cause a contact error. 
         [0033]      FIG. 4  is a cross-sectional view illustrating the alignment checking apparatus taken along line IV-IV′ of  FIG. 3 , and  FIG. 5  is a cross-sectional view illustrating the alignment checking apparatus taken along line V-V′ of  FIG. 3 . 
         [0034]    Referring to  FIGS. 4 and 5 , the opening  125  is provided in the edge pad  120 . The connection wiring  110   a  of the center pad  110  is located in the opening  125 . The connection wiring  110   a  is formed on the same plane as the edge pad  120 , for example, on the interlayer insulating layer  105  without use of the lower layer below the edge pad  120 . 
         [0035]    In an embodiment, the edge pad  120  may be coupled to a lower wiring layer  102  through a lower contact  107 . 
         [0036]    Referring to  FIG. 6 , a first ESD circuit unit  210  may be coupled between a center pad  110  and a first voltage transfer pad P 1 , and a second ESD circuit unit  220  may be coupled between an edge pad  120  and a second voltage transfer pad P 2 . 
         [0037]    The first and second ESD circuit units  210  and  220  may be provided to discharge electrostatic which may be generated when the probe needle  200  of  FIG. 3  is in contact with the center pad  110  or the edge pad  120 . 
         [0038]    In an embodiment, the edge pad  120  may include the opening  125 , and the first connection wiring  110   a  electrically connecting the first ESD circuit unit  210  and the center pad  110  may extend through the opening  125 . 
         [0039]    The edge pad  120  may be coupled to the second ESD circuit unit  220  through the second connection wiring  120   a.    
         [0040]      FIG. 7  is an internal circuit diagram illustrating the first or second ESD circuit unit  210  or  220  of  FIG. 6 . 
         [0041]    Referring to  FIG. 7 , the first or second ESD circuit unit  210  or  220  may include a MOS transistor TM, an inverter IN, and a transfer gate TG. 
         [0042]    The MOS transistor TM may include a gate to which an operation voltage VDD is applied, a drain coupled to the center pad  110  or the edge pad  120 , and a source coupled to a ground terminal. 
         [0043]    The inverter IN may be coupled to the drain of the MOS transistor, and the center pad  110  or the edge pad  120 , and output a logic level opposite to the center pad  110  or the edge pad  120  when the voltage of the center pad  110  or the edge pad  120  is applied thereto. 
         [0044]    The transfer gate TG may selectively provide an output signal of the inverter IN to the first or second voltage transfer pad P 1  or P 2  in response to a probe test signal TE. 
         [0045]    When electrostatic charge is generated at the center pad  110  and/or the edge pad  120  during the probe test, the electrostatic charge may be discharged through the MOS transistor TM which is always turned on, and therefore the first and the second voltage transfer pads P 1  and P 2  may be protected from the electrostatic charge. 
         [0046]    Various types of ESD circuits other than the ESD circuit illustrated in  FIG. 7  may be used as the first and second ESD circuit units  210  and  220  of the embodiment. 
         [0047]    The center pad and the edge pad may be implemented in various shapes. 
         [0048]    For example, as illustrated in  FIG. 8 , an edge pad  121  may be formed in a concave form, and a center pad  111  may be formed in a convex form, when viewed from above. The edge pad  121  may have an opening  125   a,  and the opening  125   a  may have a width w 3  greater than a width w 4  of the center pad  111 . The center pad  111  may be surrounded with the edge pad  121  except for the opening  125   a.  The center pad  111  may be connected to the outside of the edge pad  121  through a connection wiring  111   a  without a bypass to a lower layer. 
         [0049]    Referring to  FIG. 9 , an edge pad  122  may include a pair of openings  125   a  and  125   b  facing to each other. First and second connection wirings  112   a  and  112   b  coupled to a center pad  112  may extend through the pair of openings  125   a  and  125   b.    
         [0050]    Referring to  FIG. 10 , an edge pad  123  surrounding a center pad  110  may have at last two openings  125 . The edge pad  123  may be divided into unit edge pads such as a first unit edge pad  123   a  and a second unit edge pad  123   b.  The first unit edge pad  123   a  may be electrically coupled to a first voltage providing unit  310 , and the second unit edge pad  123   b  may be electrically coupled to a second voltage providing unit  320 . For example, each of the first and second unit edge pads  123   a  and  123   b  may have “L” shape. The center pad  110  may be electrically coupled to a third voltage providing unit  330  through a first connection wiring  110   a  which passes through any one among a plurality of openings  125 . 
         [0051]    Voltage levels provided from the first voltage providing unit  310 , the second voltage providing unit  320 , and the third voltage providing unit  330  may be different from each other. The first to third voltage providing unit  310  to  330  may include voltage regulators. 
         [0052]    Therefore, voltage level may vary according to which pad comes into contact with the probe needle, and thus a tester may figure out where the probe needle is located. 
         [0053]    According to an embodiment of the inventive concept, the alignment checking apparatus for probe test may include an opening, which is provided for a connection wiring of a center pad, in an edge pad region. The center pad may be coupled to the outside of the edge pad region without a bypass to a lower layer. Therefore, the alignment checking apparatus may be formed without an etching process and a contact formation process for the bypass to a lower layer, which may cause an electrical defect. 
         [0054]    The above embodiment of the present invention is illustrative and not limitative. Various alternatives and equivalents are possible. The invention is not limited by the embodiment described herein. Nor is the invention limited to any specific type of integrated circuit or semiconductor device. Other additions, subtractions, or modifications are obvious in view of the present disclosure and are intended to fall within the scope of the appended claims.