Abstract:
Embodiments relate to a semiconductor having a capacitor and a method of fabricating the same, that may be capable of simplifying a manufacturing process and increasing a capacitance of a capacitor. In embodiments, a method of forming a capacitor may use a dual damascene process and may be simplified by simultaneously forming a contact plug for applying a bias voltage to a bottom electrode and a capacitor.

Description:
[0001]     The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2005-0 133183 (filed on Dec. 29, 2005), which is hereby incorporated by reference in its entirety.  
       BACKGROUND  
       [0002]     A Merged Memory Logic (MML) device may be a device including a Dynamic Random Access Memory (DRAM) and peripheral circuits integrated on a single chip.  
         [0003]     MML has improved the functionality of multimedia and may allow high-integration and high-speed operation of a semiconductor device to be more effectively achieved. In addition, in the field of an analog circuit requiring high-speed operation, a semiconductor device having a mass storage capacitor is being developed.  
         [0004]     A capacitor may have a Polysilicon-Insulator-Polysilicon (PIP) structure. In such a situation, a top electrode and a bottom electrode may include conductive polysilicon.  
         [0005]     However, a capacitor having such a PIP structure may have various disadvantages. For example, a capacitance may be lowered because natural oxide layers may be formed due to an oxidation reaction occurring at the interfacial surface between the top/bottom electrodes and a dielectric thin film.  
         [0006]     Further, due to a depletion region that may be formed in a polysilicon layer, a PIP capacitor may have a lowered capacitance and thus may be unsuitable for high-speed and/or high-frequency operation.  
         [0007]     A MIM type capacitor, on the other hand, may be used for high performance semiconductor devices. It may have low resistivity and may not cause parasitic capacitance derived from the depletion.  
         [0008]      FIGS. 1A and 1B  are example cross-sectional diagrams to illustrate a related art semiconductor and method for fabricating a semiconductor device having an MIM capacitor and a damascene interconnection structure.  
         [0009]     Referring to  FIG. 1A , first metallic interconnection  15  and second metallic interconnection  20  may be formed on bottom insulating layer  10  of semiconductor substrate  1 . First and second metallic interconnections  15  and  20  may not form a step difference relative to bottom insulating layer  10 .  
         [0010]     A metallic layer may be formed on a resultant structure where first metallic interconnection  15  and second metallic interconnection  20  are formed. The metallic layer may be patterned, and may form bottom electrode  25  of a capacitor making contact with a top surface of second metallic interconnection  20 .  
         [0011]     Dielectric layer  30  may be formed on a resultant structure including bottom electrode  25 . Another metallic layer may then be formed on dielectric layer  30 , and may be patterned such that top electrode  35  of the capacitor is formed, for example at a position corresponding to bottom electrode  25 . Interlayer dielectric layer  40  may be formed on a resultant structure where top electrode  35  may be formed.  
         [0012]     Referring to  FIG. 1B , a top surface of interlayer dielectric layer  40  may be planarized, for example by a CMP process. Then, interlayer dielectric layer  40  and dielectric layer  30  may be etched, for example to form via hole V 1  that may expose a top surface of first metallic interconnection  15 .  
         [0013]     First trench T 1  may be formed on a top of via hole V 1 . Second trench T 2 , that may expose a top surface of top electrode  35 , may be formed. Via hole V 1  and first and second trenches T 1  and T 2  may be filled with Cu. A CMP process may then be performed with respect to Cu, and may thereby form a damascene interconnection structure  45  and contact plug  50 .  
         [0014]     The above described technique may have various problems. For example, a metallic interconnection process for applying a bias voltage to a bottom electrode of the capacitor may be necessary, and a process may become more complex because the via hole and the trench of the top electrode may not be able to be simultaneously formed.  
         [0015]     In addition, capacitors may increasingly be important components in a structure of a logic device. Hence, there may be a technical need to improve a capacitance of a capacitor.  
         [0016]     There may be several methods for maintaining and/or increasing a capacitance of a capacitor at an appropriate value in a limited unit area, as expressed by the equation C=εAs/d (ε: dielectric constant, As: surface area of electrode, d: thickness of dielectric element). Some of the suggested methods include reducing a thickness of a dielectric element, increasing a surface area of a electrode, and using a material having a high dielectric constant ε.  
         [0017]     With respect to increasing a surface area of an electrode, a related art analog capacitor may use a metallic interconnection as top and bottom electrodes. Accordingly the effective surface area of the related art analog capacitor may be formed as a plane. Hence, there may be a limitation regarding increasing a surface area of the electrode.  
         [0018]      FIGS. 2A  to  2 E are example cross-sectional diagrams to illustrate a related art method for fabricating a semiconductor device having a capacitor and a contact plug between interlayer interconnections.  
         [0019]     Referring to  FIG. 2A , interlayer dielectric layer  2  may be formed. Metallic conductive layer may be formed and patterned on a top of interlayer dielectric layer  2  such that bottom electrode  4 A and bottom interconnection  4 B may be formed. A semiconductor substrate (not shown), on which the semiconductor device may be formed, may exist under interlayer dielectric layer  2 .  
         [0020]     Inter-metallic dielectric layer  6  may be formed and planarized on bottom electrode  4 A and bottom interconnection  4 B.  
         [0021]     Referring to  FIG. 2B , contact hole  8  that may expose bottom electrode  4 A of the capacitor may be formed by using a known photolithographic process.  
         [0022]     Contact hole  8 , that may expose bottom electrode  4 A, may constitute an effective surface area of the capacitor, so the capacitor may have a large effective surface area.  
         [0023]     Referring to  FIG. 2C , dielectric layer  10  may be formed on a surface of the substrate including contact hole  8 .  
         [0024]     Referring to  FIG. 2D , via hole  12 , that may expose bottom interconnection  4 B, may be formed, for example using a known photolithographic process.  
         [0025]     Referring to  FIG. 2E , a top interconnection conductive layer may be formed and patterned on a surface of semiconductor substrate, and a form top electrode  14 A and top interconnection  14 B of the capacitor.  
         [0026]     The MIM capacitor as described above may be limited as to an increase in capacitance of the capacitor because the effective surface area of the capacitor is formed as a plane.  
       SUMMARY  
       [0027]     Embodiments relate to a semiconductor device having a capacitor, and a method of fabricating a semiconductor device having a capacitor. Embodiments relate to a semiconductor device having a capacitor and a method of fabricating the same, that may be capable of simplifying the manufacturing process and increasing a capacitance of the capacitor.  
         [0028]     Embodiments relate to a capacitor that can be simultaneously formed with a contact plug for applying a bias voltage to a bottom electrode through a capacitor fabricating process using a dual damascene process.  
         [0029]     Embodiments relate to a capacitor and a method of fabricating a capacitor that may be capable of simplifying a manufacturing process and increasing a capacitance of a capacitor by coupling capacitors in a row.  
         [0030]     In embodiments, a semiconductor device having capacitors may include a substrate having a capacitor region and a contact plug region, a first conductor formed on the substrate, at least one first insulating layer formed on an entire surface of the substrate including the first conductor, a first contact hole extending by passing through the first insulating layer to expose a first conductive part of the capacitor region, a second contact hole extending by passing through the first insulating layer to expose a first conductive part of the contact plug region, a second conductor formed in the first contact hole and the second contact hole, a first capacitor insulating layer formed on the second conductor aligned in the first contact hole, a third conductor formed in the first contact hole, such that the third conductor is placed on the capacitor insulating layer, and having a trench on a top thereof, a second capacitor insulating layer formed in the trench, a fourth conductor formed in the trench, such that the fourth conductor is placed on the second capacitor insulating layer, and having a trench on a top thereof, a contact plug formed on the second conductor aligned in the second contact hole, at least one second insulating layer formed on an entire surface of the substrate including the contact plug and the fourth conductor, a third contact hole extending by passing through the second insulating layer to expose the third conductor, a fourth contact hole extending by passing through the second insulating layer to expose the fourth conductor and the contact plug, a first interconnection layer formed in the third contact hole, and a second interconnection layer formed in the fourth contact hole.  
         [0031]     First to third contact holes may be formed as via holes or trenches. The fourth contact hole may include a first via hole that may expose the fourth conductor, a second via hole for exposing the contact plug, and a trench formed on tops of the first and second via holes to overlap the first and second via holes.  
         [0032]     The semiconductor device may also include a third insulating layer having a fifth contact hole where the first conductor is formed.  
         [0033]     In embodiments, a method of fabricating a semiconductor device having capacitors may include preparing a substrate having a capacitor region and a contact plug region, forming a first insulating layer having a first contact hole on an entire surface of the surface, forming a first conductor in the first contact hole, forming at least one second insulating layer on an entire surface of the substrate including the first insulating layer and the first conductor, forming a second contact hole extending by passing through the second insulating layer to expose a first conductive part of the capacitor region, and a third contact hole extending by passing through the second insulating layer to expose a first conductive part of the contact plug region, forming a second conductor in each of the second contact hole and the third contact hole, forming a first capacitor insulating layer in the second contact hole such that the first capacitor insulating layer is placed on the second conductor, forming a third conductor in the second contact hole such that the third conductor is placed on the first capacitor insulating layer, and forming a contact plug in the third contact hole such that the contact plug is placed on the second conductor, forming the third conductor in the second contact hole such that the third conductor is placed on the first capacitor insulating layer, forming a trench by removing a portion of the third conductor, forming a second capacitor insulating layer in the trench, forming a fourth conductor in the trench such that the fourth conductor is placed on the second capacitor insulating layer, forming at least one third insulating layer on an entire surface of the substrate including the contact plug and the fourth conductor, forming a fourth contact hole extending by passing through the third insulating layer to expose the third conductor, and forming a fifth contact hole extending by passing through the third insulating layer to expose the fourth conductor and the contact plug, and forming a first interconnection layer in the third contact hole, and forming a second interconnection layer in the fourth contact hole.  
         [0034]     The second to fourth contact holes may be formed as via holes or trenches. The fifth contact hole may include a first via hole for exposing the fourth conductor, a second via hole for exposing the contact plug, and a trench formed on tops of the first and second via holes to overlap the first and second via holes.  
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0035]      FIGS. 1A  to  2 E are example cross-sectional diagrams illustrating a related art semiconductor and method for fabricating a MIM capacitor of a dual damascene structure; and  
         [0036]      FIGS. 3A  to  3 P are example diagrams illustrating a semiconductor and method of fabricating a semiconductor having capacitors according to embodiments. 
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0037]     Referring to  FIG. 3A , substrate  300  may have a contact plug region and a capacitor region. First insulating layer  401  may be formed on a surface of substrate  300 .  
         [0038]     First insulating layer  401  may be patterned, for example, through a photo and etching process such that trench  701  may be formed in first insulating layer  401 .  
         [0039]     Referring to  FIG. 3B , first conductor  501  may be formed on a surface of substrate  300  including trench  701 . First conductor  501  may be planarized, for example, through a Chemical Mechanical Polishing (CMP) process. Accordingly, first conductor  501  may be buried in trench  701  formed in first insulating layer  401 .  
         [0040]     Referring to  FIG. 3C , second insulating layer  402 , third insulating layer  403 , and fourth insulating layer  404  may be sequentially laminated on a surface of substrate  300  including first conductor  501  and first insulating layer  401 .  
         [0041]     Referring to  FIG. 3D , fourth insulating layer  404  and third insulating layer  403  may be patterned, for example, through a photo and etching process, such that first via hole  801  may be formed in the capacitor region and second via hole  802  may be formed in the contact plug region.  
         [0042]     Referring to  FIGS. 3E and 3F , fifth insulating layer  405  may be formed on a surface of substrate  300  where first and second via holes  801  and  802  may be formed. Fifth and second insulating layers  405  and  402  may be patterned, for example, through a photo and etching process, such that first trench  901  may be formed in the capacitor region and second trench  902  may be formed in the contact plug region.  
         [0043]     First via hole  801  may pass through second insulating layer  402 , which may be placed in the capacitor region, and may expose a portion of conductor  501 .  
         [0044]     Second via hole  802  may pass through second insulating layer  402 , which may be placed in the contact plug region, and may expose a portion of conductor  501 .  
         [0045]     First trench  901  may be coupled to first via hole  801  of the capacitor region. Accordingly, a width of first trench  901  may be identical to that of first via hole  801 . A depth of first via hole  801  may be as deep as first trench  901 , according to embodiments.  
         [0046]     In other words, a contact hole of a single damascene structure that may expose a portion of first conductor  501  may be formed in the capacitor region.  
         [0047]     Second trench  902  may be coupled with second via hole  802  of the contact plug region. A width of second trench  902  may be wider than that of second via hole  802 . That is, a contact hole of a dual damascene structure that exposes a portion of first conductor  501  may be formed in the contact plug region.  
         [0048]     Referring to  FIG. 3G , second conductor  502  may be laminated on a surface, for example where first and second trenches  901  and  902  and first and second via holes  801  and  802  may be formed. First capacitor insulating layer  601  may be laminated and/or formed on second conductor  502  within the first trench  901 .  
         [0049]     Referring to  FIG. 3H , first capacitor insulating layer  601  may be patterned, for example, through a photo and etching process, such that first capacitor insulating layer  601  may be formed only along inner walls of first trench  901  and first via hole  801 .  
         [0050]     That is, first capacitor insulating layer  601  may be formed only in the capacitor region and not formed in the contact plug region.  
         [0051]     Referring to  FIG. 3I , metallic layer  555  may be formed on a surface of substrate  300 , including first capacitor insulating layer  601  and second conductor  502 .  
         [0052]     Referring to  FIG. 3J , metallic layer  555 , second conductor  502 , and first capacitor insulating layer  601  may be polished through a CMP process, until a surface of fifth insulating layer  405  appears.  
         [0053]     Third conductor  503 , which may be buried in first via hole  801  and first trench  901 , may thus be formed in the capacitor region. Contact plug  777 , which may be buried in second via hole  802  and second trench  902 , may thus be formed in the contact plug region.  
         [0054]     Referring to  FIG. 3K , a portion of third conductor  503  may be removed and trench  702  may thus be formed.  
         [0055]     Referring to  FIG. 3L , second capacitor insulating layer  602  and metallic layer  556  may be sequentially deposited on a surface of substrate  300  including trench  702  and second capacitor insulating layer  602 .  
         [0056]     Referring to  FIG. 3M , metallic layer  556  and second capacitor insulating layer  602  may be polished through a CMP process, until a surface of fifth insulating layer  405  appears. Second capacitor insulating layer  602  and fourth conductor  504 , which may be buried in trench  702 , may be formed in the capacitor region.  
         [0057]     Referring to  FIG. 3N , sixth insulating layer  406  may be formed on a surface of substrate  300  including second capacitor insulating layer  602  and fourth conductor  504 . Sixth insulating layer  406  may be patterned, for example, through a photo and etching process such that third via hole  803  and third trench  903 , that may expose a portion of third conductor  503  may be formed. Fourth via hole  804  and fourth trench  904 , which may expose a portion of fourth conductor  504 , and fifth via hole  805 , which may expose a portion of contact plug  777 , may be formed. Fourth trench  904  may be commonly coupled to fourth via hole  804  and fifth via hole  805 . That is, fourth trench  904  may be formed on tops of fourth and fifth via holes  804  and  805 , and may overlap both of fourth and fifth via holes  804  and  805 .  
         [0058]     Referring to  FIG. 30 , metallic layer  999  may be formed on a surface of substrate  300  including third via hole  803 , fourth via hole  804 , fifth via hole  805 , third trench  903  and fourth trench  904 .  
         [0059]     Referring to  FIG. 3P , metallic layer  999  may be polished, for example through a CMP process, until a surface of sixth insulating layer  406  appears.  
         [0060]     First and second interconnection layers  991  and  992  may be formed through the above described processes.  
         [0061]     First interconnection layer  991  may be electrically coupled with third conductor  503 , and second interconnection layer  992  may be electrically coupled with fourth conductor  504  and contact plug  777 .  
         [0062]     Accordingly, two capacitors connected in parallel to each other may be formed in the capacitor region.  
         [0063]     That is, a first capacitor including second conductor  502 , third conductor  503  and first capacitor insulating layer  601 , and a second capacitor including third conductor  503 , fourth conductor  504  and second capacitor insulating layer  602  may be provided.  
         [0064]     Second conductor  502  of the first capacitor may be electrically coupled to fourth conductor  504  of the second capacitor through first conductor  501 , second conductor  502  (second conductor  502  of the contact plug region), contact plug  777 , and the second interconnection layer  992 . Therefore, the first capacitor and the second capacitor may be connected in parallel to each other.  
         [0065]     According to embodiments, each of the dielectric layers (first to sixth insulating layers  401  to  406 ), and first and second capacitor insulating layers  601  and  602  may be formed by using a nitride layer, a SiC aluminum oxide, or a silicon oxide.  
         [0066]     First, second, third, and fourth conductors  501 ,  502 ,  503 , and  504  may be formed of a TaN or a multilayer having a TaN, a TiN or a multilayer having a TiN, and a WN or a multilayer including a WN. Further, the capacitor dielectric layer may act as a capacitor interlayer insulating layer, and may be formed of any one of a Nitride layer, a TEOS, a Tantalum based oxide, and an Aluminum based oxide.  
         [0067]     According to embodiments, a semiconductor device may have capacitors, which may be connected in a row. Capacitance of the capacitor may thus be improved.  
         [0068]     That is, the capacitors provided in the semiconductor device according to embodiments may have mass storage capacitance, for example as compared to a related art capacitor.  
         [0069]     Further, according to embodiments contact plug  777  and the capacitors may be fabricated through the same process. Accordingly, a fabrication process may be simplified.  
         [0070]     It will be apparent to those skilled in the art that various modifications and variations can be made to embodiments. Thus, it is intended that embodiments cover modifications and variations thereof within the scope of the appended claims. It is also understood that when a layer is referred to as being “on” or “over” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present.