Abstract:
A capacitor capable of being formed in a vertical plane without an additional mask process and/or deposition process and a method of manufacturing the same are provided. The capacitor includes: a first conductive line formed on a substrate; a first interlayer dielectric including a first via hole formed at an upper portion of the first conductive line, and a second and third via hole pair formed at a region of the substrate; a first barrier metal layer and a contact plug formed in the first via hole; and first and second capacitor electrodes formed in the second and third via holes, respectively. The first and second capacitor electrodes and the first interlayer dielectric disposed between the first and second capacitor electrodes form a vertically constructed capacitor.

Description:
RELATED APPLICATION(S)  
       [0001]     This application claims priority under 35 U.S.C. §119(e) of Korean Patent Application No. 10-2005-0132706 filed Dec. 28, 2005, which is incorporated herein by reference in its entirety.  
       FIELD OF THE INVENTION  
       [0002]     The present invention relates to a capacitor and a method for manufacturing the same.  
       BACKGROUND OF THE INVENTION  
       [0003]     A merged memory logic (MML) device is an integrated device that incorporates a memory cell array, such as a dynamic random access memory (DRAM), and an analog or a peripheral circuit into a single chip. Since multimedia functions have been enhanced by the introduction of the MML, it is possible to efficiently achieve integration and high-speed of semiconductor devices.  
         [0004]     Development is underway for manufacturing a capacitor having high capacitance for an analog circuit in which high-speed operation is needed. There are two main types of capacitors used in analog circuits. They are polysilicon/insulator/polysilicon (PIP) type capacitors and metal/insulator/metal (MIM) type capacitors. In general, because conductive polysilicon is used for the upper and lower electrodes of a PIP type capacitor, a natural oxide forms due to an oxidation occurring at the interface between the upper/lower electrode and a dielectric thin layer. Because of the natural oxide formation, the conventional PIP capacitor has a defect that lowers its capacitance.  
         [0005]     In addition, the capacitance decreases due to a depletion region formed on a polysilicon layer. Thus, there is a disadvantage in that the PIP capacitor is not suitable for high-speed and high-frequency operations. To overcome these disadvantages, a metal-insulator-silicon (MIS) or a metal-insulator-metal (MIM) is used. The MIM type capacitor is generally used for high performance semiconductor devices because it has low resistivity and does not cause parasitic capacitance derived from the depletion.  
         [0006]     Hereinafter, a related art capacitor will be described with reference to the accompanying drawings.  
         [0007]      FIG. 1  is a sectional view of showing a structure of a MIM capacitor according to the related art.  
         [0008]     As shown in  FIG. 1 , a capacitor according to the related art includes a first interlayer dielectric  10  having the first contact hole formed on a substrate. A Metal-Insulator-Metal (MIM) type capacitor is formed at an upper portion of the first interlayer dielectric  10 . The MIM type capacitor includes a first conductive layer  11 , a first insulating layer  13 , and a second conductive layer  14 , which are sequentially deposited at an upper portion of the first interlayer dielectric  10 . Here, a second interlayer dielectric  15  is formed on an entire surface of the substrate including the MIM type capacitor. The first conductive layer  11 , functioning as a lower electrode of the capacitor, is connected to a third conductive layer  17   a  formed on the second interlayer dielectric  15  through a first plug  16 , which is formed in a second contact hole.  
         [0009]     In addition, the second conductive layer  14 , functioning as an upper electrode of the capacitor, is connected to a fourth conductive layer  17   b  formed on the second interlayer dielectric  15  through a second plug  20 , which is formed in a third contact hole  
         [0010]     In the capacitor according to the related art, a first conductive layer  11 , a first insulating layer  13 , and a second conductive layer  14  are flatly constructed of layers in horizontal planes. In order to increase the capacitance through increasing the surface area of the electrodes, the related art capacitor is expanded along the horizontal plane.  
         [0011]     Accordingly, in the capacitor according to the related art, there is a limit to increasing the length and width of a capacitor with a defined area.  
       BRIEF SUMMARY  
       [0012]     Accordingly, embodiments of the present invention are directed to a capacitor and a method for manufacturing the same that substantially obviates one or more problems due to limitations and/or disadvantages of the related art.  
         [0013]     Accordingly, it is an object of embodiments of the present invention to provide a capacitor capable of being formed in a vertical plane without an additional mask process or deposition process and a method of manufacturing the same.  
         [0014]     Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be earned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
         [0015]     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a capacitor comprising: a first conductive line formed on a substrate; a first interlayer dielectric having a first via hole formed at an upper portion of the first conductive line, and a second and third via hole pair formed at one region of the substrate; a first barrier metal layer and a contact plug formed in the first via hole; a first capacitor electrode formed in the second via hole; and a second capacitor electrode formed in the third via hole, wherein the first and second capacitor electrodes and the first interlayer dielectric disposed between the first and second capacitor electrodes form a vertically constructed capacitor.  
         [0016]     In another aspect of the present invention, there is provided a method for manufacturing a capacitor comprising: forming a first conductive line on a substrate; forming a first interlayer dielectric on the substrate including the first conductive line; forming a first via hole through the first interlayer dielectric at an upper portion of the first conductive line, and forming a second and third via hole pair being adjacent to each other through the first interlayer dielectric at a region of the substrate; forming a first barrier metal layer and a contact plug in the first via hole; and forming first and second capacitor electrodes in the second and third via holes, respectively.  
         [0017]     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:  
         [0019]      FIG. 1  is a view for showing a structure of a capacitor according to the related art;  
         [0020]      FIG. 2  is a view showing a capacitor and a peripheral metal layer thereof according to an embodiment of the present invention;  
         [0021]      FIG. 3  is a cross-sectional view for showing a structure of a capacitor according to an embodiment of the present invention; and  
         [0022]      FIGS. 4 through 8  are cross-sectional views for illustrating a method for manufacturing the capacitor according to an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  
         [0024]     Hereinafter, a method for manufacturing a semiconductor device according to an embodiment of the present invention will be described with reference to the accompanying drawings.  
         [0025]     In the description of an embodiment of the present invention, when something is formed “on” each layer, the “on” includes the concepts of “directly and indirectly”.  
         [0026]      FIG. 2  is a view showing a capacitor and a peripheral metal layer thereof according to an embodiment of the present invention.  FIG. 3  is a cross-sectional view for showing a structure of a capacitor according to an embodiment of the present invention.  
         [0027]     As shown in  FIGS. 2 and 3 , a capacitor according to an embodiment of the present invention includes a plurality of first conductive lines  41   a ,  41   b ,  41   c , and  41   d  and a first interlayer dielectric  42 . The plurality of first conductive lines  41   a ,  41   b ,  41   c , and  41   d  can be formed on a semiconductor substrate  40 . The first interlayer dielectric  42  can be formed on the semiconductor substrate  40  including on the plurality of first conductive lines  41   a ,  41   b ,  41   c , and  41   d.    
         [0028]     First via holes  43   a  can be formed through the first interlayer dielectric  42  at the first conductive lines  41   a ,  41   b ,  41   c , and  41   d . Second and third via holes  43   b  and  43   c , and fourth and fifth via holes  43   d  and  43   e  can be formed through the first interlayer dielectric  42  at one region of a semiconductor substrate  40  in pairs of two adjacent via holes.  
         [0029]     Although not shown in the drawings, a conductive ion can be implanted in the semiconductor substrate  40  below the second and third via holes  43   a  and  43   b , and fourth and fifth via holes  43   d  and  43   e    
         [0030]     Although two pairs of via holes are descried in this embodiment, the present invention is not limited thereto. That is, more pairs of via holes can be formed.  
         [0031]     Referring again to  FIGS. 2 and 3 , a first barrier metal layer  44   a  and a contact plug  45   a  can be formed in the first via holes  43   a , which are formed on the first conductive lines  41   a ,  41   b ,  41   c , and  41   d . First and second capacitor electrodes  46   a  and  46   b  can be formed in the second and third via holes  43   b  and  43   c , and are made of the barrier metal layer and the contact plug formation material. Third and fourth capacitor electrodes  46   c  and  46   d  are also formed in the fourth and fifth via holes  43   d  and  43   e , and are made of the barrier metal layer and the contact plug formation material.  
         [0032]     First and second dielectric layers  42   a  and  42   b  remain between the first and second capacitor electrodes  46   a  and  46   b , and between the third and fourth capacitor electrodes  46   c  and  46   d.    
         [0033]     That is, a Metal-Insulator-Metal (MIM) type first capacitor  50   a  of a vertical construction is composed of the first and second capacitor electrodes  46   a  and  46   b  and the first capacitor dielectric layer  42   a  disposed between the first and second capacitor electrodes  46   a  and  46   b . In addition, a MIM type second capacitor  50   b  of a vertical construction is composed of the third and fourth capacitor electrodes  46   c  and  46   d  and the second capacitor dielectric layer  42   b  disposed between the third and fourth capacitor electrodes  46   c  and  46   d.    
         [0034]     A second conductive line  51   a  can be connected to the first barrier metal layer  44   a  and the contact plug  45   a , which are formed in the first via holes  43   a . Conductive pads  51   b ,  51   c ,  51   d , and  51   e  can be formed at upper portions of the first and second capacitor electrodes  46   a  and  46   b , and the third and fourth capacitor electrodes  46   c  and  46   d , respectively.  
         [0035]     As describe above, the first and second capacitor electrodes can be formed in pairs of via holes. One vertical capacitor is composed of the first and second capacitor electrode and a first interlayer dielectric remaining between the first and second capacitor electrodes.  
         [0036]     The following is a description of a method for manufacturing a capacitor according to an embodiment of the present invention having a construction illustrated above.  
         [0037]      FIGS. 4 through 8  are cross-sectional views for describing a method for manufacturing a capacitor according to an embodiment of the present invention.  
         [0038]     Referring to  FIG. 4 , a first conductive layer can be deposited on a semiconductor substrate  40 . Then, a first photoresist layer (not shown) can be coated on the first conductive layer, and selectively patterned.  
         [0039]     Next, the first conductive layer can be etched using the patterned first photoresist layer as a mask to form first conductive lines  41   a ,  41   b ,  41   c , and  41   d.    
         [0040]     Then, referring to  FIG. 5 , a first interlayer dielectric  42  can be deposited on the semiconductor substrate  40  including the first conductive lines  41   a ,  41   b ,  41   c , and  41   d . A second photoresist layer can be coated on the substrate and patterned to expose the first conductive lines  41   a ,  41   b ,  41   c , and  41   d  and a region of the semiconductor substrate  40 . First via holes  43   a  to contact the first conductive lines  41   a ,  41   b ,  41   c , and  41   d , and. a pair of second and third via holes  43   b  and  43   c  and a pair of fourth and fifth via holes  43   d  and  43   e  to contact a region of the semiconductor substrate  40  that can be formed using the patterned second photoresist layer as a mask.  
         [0041]     Although not shown in drawings, a conductive ion can be implanted in the semiconductor substrate  40  disposed at lower portions of the second and third via holes  43   b  and  43   c , and fourth and fifth via holes  43   d  and  43   e.    
         [0042]     Although only two pairs of via holes have been described, the present invention is not limited thereto. That is, more via holes can be formed.  
         [0043]     Referring to  FIG. 6 , a first barrier metal layer  44  and a second conductive layer  45  can be formed on the first interlayer dielectric  42  including the first to fifth via holes  43   a ,  43   b ,  43   c ,  43   d , and  43   d . Here, the second conductive layer  45  can form a plug. In a specific embodiment, the second conductive layer can be formed of tungsten.  
         [0044]     Then, as shown in  FIG. 7 , the first barrier metal layer  44  and the second conductive layer  45  can be planarized by a chemical mechanical polishing process to expose the first interlayer dielectric  42 .  
         [0045]     Accordingly, a first barrier metal layer  44   a  and a contact plug  45   a  are formed in the first via holes  43   a  at upper portions of the first conductive lines  41   a ,  41   b ,  41   c , and  41   d . First and second capacitor electrodes  46   a  and  46   b  are formed in the second and third via holes  43   b  and  43   c , respectively, and are composed of the barrier metal layer and a contact plug formed of the second conductive layer. In the same manner, third and fourth capacitor electrodes  46   c  and  46   d  are formed in the fourth and fifth via holes  43   d  and  43   e , respectively, and are composed of the barrier metal layer and a contact plug formed of the second conductive layer.  
         [0046]     Moreover, the first dielectric layer  42  between each via hole pair functions as first and second capacitor dielectric layers  42   a  and  42   b  between the first and second capacitor electrodes  46   a  and  46   b , and between the third and fourth capacitor electrodes  46   c  and  46   d , respectively.  
         [0047]     That is, a MIM type first capacitor  50   a  of a vertical construction can be composed of the first and second capacitor electrodes  46   a  and  46   b , and the first capacitor dielectric layer  42   a  formed therebetween. Further, a MIM type second capacitor  50   b  of a vertical construction can be composed of the third and fourth capacitor electrodes  46   c  and  46   d  and the second capacitor dielectric layer  42   b  formed therebetween.  
         [0048]     Next, referring to  FIG. 8 , a third conductive layer can be deposited on the first interlayer dielectric  42 , and a third photoresist layer can be coated and patterned thereon. Then, the third conductive layer can be selectively etched using the patterned third photoresist layer as a mask to form a second conductive line  51   a  on the first barrier metal layer  44   a  and the contact plug  45   a  formed in the first via holes  43   a  and conductive pads  51   b ,  51   c ,  51   d , and  51   e  at upper portions of each of the first and second capacitor electrodes  46   a  and  46   b , and third and fourth capacitor electrodes  46   c  and  46   d.    
         [0049]     Through the aforementioned process, first and second capacitor electrodes are formed in a pair of via holes. The first and second capacitor electrodes can form one vertical capacitor with an interlayer dielectric between the first and second capacitor electrodes.  
         [0050]     As is clear from the forgoing description, in the capacitor and the method for manufacturing the same according to embodiments of the present invention, the present invention can provide a capacitor of a vertical construction during a formation of a via hole and a formation of a barrier metal layer and a contact hole in the via hole without an additional mask  
         [0051]     It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application.