Abstract:
A contact of semiconductor device and manufacturing method thereof prevent generation or inlet of noise through a contact plug which connects wires in different layers. The contact includes a lower wire, an insulating layer covering the lower wire, a contact plug connected to the lower wire through the insulating layer, a conductive tube encircling the contact plug and having the insulating layer in between, and an upper wire connected to the contact plug.

Description:
[0001]    The present application claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2008-0089839 (filed on Sep. 11, 2008), which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    Generally, a semiconductor device is manufactured by several distinct processes such as oxidation, etching, and ion implantation. In order to connect multiple semiconductor layers generated by the distinct processes, contact holes and contact plugs may be formed. 
         [0003]    Contact holes may be formed by a photolithography process. A photolithography process may be performed by optically exposing and developing a photosensitive layer, coated over a wafer, using a mask on which patterns to be etched are homologously formed. The areas exposed by the developed photosensitive layer may then be etched. 
         [0004]    A contact hole formed by etching may be filled by metals such as tungsten (W) or copper (Cu), and a metal filling formed in this manner is called a contact plug. The contact hole and contact plug are used to electrically connect lower and upper wires. Since a contact hole may be formed as a circular hole, the contact plug will have a cylinder shape. 
         [0005]    In a semiconductor device which uses a high frequency analog signal, such as an RF transmission device, a good deal of electrical noise may be generated by or flow in through the contact plug. For example, current flowing through the contact plug creates electromagnetic waves which are not desired, and the electromagnetic waves act as noise on wires around the contact plug. In addition, the contact plug may absorb various electromagnetic waves from outside to cause an influx of noise into the wires connected to the contact plug. 
       SUMMARY 
       [0006]    Embodiments relate to contacts in a semiconductor, and a manufacturing method thereof. In particular, embodiments relate to contacts in semiconductor devices, and corresponding manufacturing methods, for preventing generation and influx of noise through a contact plug which connects wires in different layers. 
         [0007]    In accordance with embodiments, there is provided a contact of a semiconductor device, which may include a lower wire formed over a semiconductor substrate, an insulating layer covering the lower wire, a contact plug connected to the lower wire through the insulating layer, a conductive tube encircling at least a portion of the contact plug (the insulating layer extending in between the conductive tube and the contact plug), and an upper wire formed over the insulating layer and connected to the contact plug. 
         [0008]    In accordance with embodiments, there is provided a contact manufacturing method of a semiconductor device, which may include forming a lower wire over a semiconductor substrate, forming a middle insulating layer to cover the lower wire, forming a photosensitive pattern over the middle insulating layer, etching a portion of the middle insulating layer exposed by the photosensitive pattern to form a contact hole and a tube hole (with the tube hole formed around an outer circumferential edge of the contact hole), filling the contact hole and the tube hole with metal to form a contact plug and conductive tube, forming an upper insulating layer over the contact plug and the conductive tube; and forming an upper wire over the upper insulating layer, with the upper wire connected to the contact plug. 
     
    
     
       DRAWINGS 
         [0009]    Example  FIG. 1A  is a cross sectional view of a contact of a semiconductor device according to embodiments. 
           [0010]    Example  FIG. 1B  is a plan view of the contact of the semiconductor device cut away along line I-I in example  FIG. 1A . 
           [0011]    Example  FIG. 2  is a flow chart of a manufacturing method for a contact of a semiconductor device according to embodiments. 
           [0012]    Example  FIGS. 3A to 3I  are cross-sectional views of a manufacturing method for a contact of a semiconductor device according to embodiments. 
           [0013]    Example  FIG. 4  is a plane view of an image formed on a mask and wafer, in order to form a contact according to embodiments. 
           [0014]    Example  FIG. 5A  illustrates a concept of a 1 step photo etching process. 
           [0015]    Example  FIG. 5B  illustrates a concept of a 2 step photo etching process. 
       
    
    
     DESCRIPTION 
       [0016]    Example  FIG. 1A  is a cross sectional view of a contact of semiconductor device according to embodiments, and example  FIG. 1B  is a plan view of the contact of semiconductor device cut away along line I-I in example  FIG. 1A . 
         [0017]    As illustrated in example  FIGS. 1A and 1B , a contact  100  of semiconductor device may include a base insulating layer  110 , a lower wire  120  formed over the base insulating layer  110 , a lower insulating layer  130  formed over the lower wire  120 , a ground wire  140  formed over the lower insulating layer  130 , a middle insulating layer  150  formed over the ground wire  140 , a contact plug  160  formed through the middle insulating layer  150 , a conductive tube  170  connected to the ground wire  140  through the middle insulating layer  150  while being coaxial with the contact plug  160 , an upper insulating layer  180  formed over the middle insulating layer  150 , and an upper wire  190  formed over the upper insulating layer  180  and connected with the contact plug  160 . 
         [0018]    The base insulating layer  110  may be formed over a semiconductor substrate in which transistor(s), diode(s), and/or capacitor(s) may be formed. A material of the base insulating layer  110  may be any one of oxide film, nitride film, USG (Undoped Silcate Glass), PSG (Phospho Silicate Glass), BPSG (Boro-Phospho Silicate Glass), TEOS (Tetraethyl Orthosilicate), and other similar materials, but are not limited to those materials. The lower wire  120  formed over the base insulating layer  110  may be made of any one of aluminum (Al), copper (Cu), and other similar materials. A material used for the lower insulating layer  130  formed over the lower wire  120  may include, but is not limited to, oxide film, nitride film, USG, PSG, BPSG, TEOS, or other materials of a similar character. The ground wire  140  formed over the lower insulating layer  130  may be made of any one of aluminum (Al), copper (Cu) and other materials of a similar character. 
         [0019]    The middle insulating layer  150  may be formed over the ground wire  140  and lower insulating layer  130 . A material used in the middle insulating layer may be oxide film, nitride film, USG, PSG, BPSG, TEOS or other similar materials, but it is not limited to those mentioned above. Also, a contact hole  151  may be formed through the lower insulating layer  130  and the middle insulating layer  150 . The tube hole  152  may be formed through the middle insulating layer  150 , coaxial with the contact hole  151  on an outer circumferential edge of the contact hole  151 . 
         [0020]    The contact plug  160  may be formed inside the contact hole  151 , and thus be connected to the lower wire  120  through the lower insulating layer  130  and middle insulating layer  150 . The conductive tube  170  may be formed inside the tube hole  152 , coaxial with contact plug  160  and may be connected to the ground wire  140 . Here, the conductive tube  170  is separated from the lower wire  120 , having the lower insulating layer  130  in between. The contact plug  160  and the conductive tube  160  may be made of any one of tungsten (W), copper (Cu), aluminum (Al) and other similar materials, but not limited to those mentioned materials. 
         [0021]    The upper insulating layer  180  formed over the middle insulating layer  150  may be made of any one of an oxide film, nitride film, USG, PSG, BPSG, TEOS, and other similar materials, but not limited to those mentioned materials. The upper wire  190  may be formed over the upper insulating layer  180  and may be connected to the contact plug  160 . Thus, the upper wire  190  and the lower wire  120  may be electrically connected through the contact plug  160 . In addition, the upper wire  190  and the conductive tube  170  may be separated by the upper insulating layer  180 . That is, the lower part of the conductive tube  170  may be separated from the lower wire  120  by the lower insulating layer  130 , and the upper part of the conductive tube  170  may be separated from the upper wire  190  by the upper insulating layer  180 . Therefore, the length of the conductive tube  170  may be shorter than that of the contact plug  160 . The thickness of the lower insulating layer  130  and the upper insulating layer  180  may be less than that of the middle insulating layer  150 . 
         [0022]    In the contact  100  of the semiconductor device, the contact plug  160  may be wrapped in the conductive tube  170 , and the middle insulating layer  150  may be arranged in between the contact plug  160  and the conductive tube  170 . Moreover, the conductive tube  170  may be connected to the ground wire  140 . With this configuration of the contact  100 , noise generated from the contact plug  160  is not released to outside. Noise from outside cannot flow into the contact plug  160 . Thus, the contact  100  according to embodiments is less affected by noise on a semiconductor device using a high frequency analog signal similar to an RF transmission device. 
         [0023]    Example  FIG. 2  is a flowchart illustrating the manufacturing method of the contact of a semiconductor device according to embodiments. As illustrated in example  FIG. 2 , a contact manufacturing method of a semiconductor device may include forming a lower wire  120  in step S 200 , forming a lower insulating layer  130  in step S 210 , forming a ground wire  140  in step S 220 , forming a middle insulating layer  150  in step S 230 , forming a photosensitive pattern in step S 240 , etching in step S 250 , filling with metal in step S 260 , forming an upper insulating layer  180  in step S 270 , and forming an upper wire  190  in step S 280 . 
         [0024]    Example  FIGS. 3A to 3I  are cross-sectional views of the contact manufacturing method for a semiconductor device shown in example  FIG. 2 . As illustrated in example  FIG. 3A , in step S 200  of example  FIG. 2 , a lower wire  120  may be formed over the surface of a base insulating layer  110 . Here, the base insulating layer  110  may be composed of any one of oxide film, nitride film, PSG, BPSG, TEOS and other similar materials. And the lower wire  120  may be any one of aluminum (Al), copper (Cu) and other similar materials. 
         [0025]    As illustrated in example  FIG. 3B , in step S 210  of example  FIG. 2 , a lower insulating layer  130  with a predetermined thickness may be formed over the surface of the lower wire  120 . Here, the lower insulating layer  130  may be one of oxide film, nitride film, USG, PSG, BPSG, TEOS or other similar materials, but it is not limited to those mentioned above. As illustrated in example  FIG. 3C , in step S 220  of example  FIG. 2 , a ground wire  140  with a predetermined thickness may be formed over a portion of the lower insulating layer  130 . Here, the ground wire  140  may be made of any one of aluminum, copper, or other similar materials, but it is not limited to those mentioned above. 
         [0026]    As illustrated in example  FIG. 3D , in step S 230  of example  FIG. 2 , a middle insulating layer  150  with a predetermined thickness may be formed over the ground wire  140 . Here, the middle insulating layer  150  may be an oxide film, nitride film, USG, PSSG, BPSG, TEOS, or other similar materials, but it is not limited to those mentioned above. As illustrated in example  FIG. 3E , in step S 240  of example  FIG. 2 , a photosensitive pattern  310  of a predetermined shape may be formed by applying, exposing, and developing a photosensitive layer over the middle insulating layer  150 . Using this photosensitive pattern  310 , some areas of the middle insulating layer  150  may be exposed. 
         [0027]    As illustrated in example  FIG. 3F , in step S 250  of example  FIG. 2 , a portion of the middle insulating layer  150  exposed by the photosensitive pattern  310  may be etched, thereby forming contact hole  151  and tube hole  152  on the outer circumferential edge of the contact hole  151 . Here, the etching may continue until the lower wire  120  is exposed to outside. After performing etching on the middle insulating layer  150 , the photosensitive pattern  310  may also be removed by etching. 
         [0028]    As illustrated in example  FIG. 3G , in step S 260  of example  FIG. 2 , the contact hole  151  and the tube hole  152  may be filled with metal, for example, with any one of tungsten (W), copper (Cu), aluminum (Al) and other similar materials. In this connection, the contact plug  160  may be formed in the contact hole  151 , and the conductive tube  170  may be formed in the tube hole  152 . And the contact plug  160  may be connected to the lower wire  120 . Next, through a planarization process such as CMP (Chemical Mechanical Polishing), the upper surface may be planarized. 
         [0029]    Before filling the holes  151  and  152  with metal, the tube hole  152  may first be filled by a predetermined amount of an insulating layer. Thus, the conductive tube  170  formed in the tube hole  152  may be separated from the lower wire  120  by the above insulating layer. And the conductive tube  170  may be connected to the ground wire  140 . 
         [0030]    As illustrated in example  FIG. 3H , in step S 270  of example  FIG. 2 , the upper insulation layer  180  may be formed over the middle insulating layer  150 . Here, the contact plug  160  may be exposed through the middle of insulating layer  150 . In other words, by forming an opening  153  in a portion of the upper insulating layer  180 , the contact plug  160  may be exposed. And the conductive tube  170  may be covered with the upper insulating layer  180 . 
         [0031]    As illustrated in example  FIG. 3I , in step S 280 , an upper wire  190  of a predetermined thickness may be formed over the upper insulating layer  180 . Since the upper insulating layer  180  has an opening to expose the contact plug  160 , the upper wire  190  may be connected to the contact plug  160  through the opening. And the upper wire  190  may be separated from the conductive tube  170  by the upper insulating layer  180 . 
         [0032]    Through the process described above, a contact  100  in a semiconductor device may be manufactured. The contact plug  160  may be wrapped with the conductive tube  170 , with insulating layers in between. Moreover, the conductive tube  170  may be connected to ground wire  140 . Thus, noise generated by current flowing through contact plug  160  may be absorbed by the conductive tube  170  so that the noise does not propagate outside. Noise from the outside may also be absorbed by the conductive tube  170 , so is not transmitted to the contact plug  160 . 
         [0033]    Example  FIG. 4  is a plane view of an image formed on a mask and wafer for forming a contact according to embodiments. As illustrated in example  FIG. 4 , a mask pattern used in the photosensitive pattern forming step may be different from a photosensitive pattern formed over a wafer, in reality. On the mask are a first rectangular pattern M 1  and a second rectangular pattern M 2  outside and separated from the first rectangular pattern M 1 . 
         [0034]    When patterns are formed over the photosensitive layer using the mask, the first circular pattern W 1  and the second circular pattern W 2  separated from the first circular pattern W 1  may be formed on the surface of the wafer. And the first circular pattern W 1  and the second circular pattern W 2  may be coaxial. 
         [0035]    In this way, while rectangular patterns may be formed on the mask, circular patterns are formed on the wafer, because of a fine transfer area which is over a limiting resolution and diffraction effect of light when exposed. Thus, in order to eliminate pattern distortion generated by high resolution and light diffraction effect, rectangular patterns may be formed instead of the circular patterns. 
         [0036]    Example  FIG. 5A  illustrates a concept of a one step photo etching process and example  FIG. 5B  illustrates a concept of a two step photo etching process. As illustrated in example  FIG. 5A , if the pitch between patterns (here, the pattern is a contact hole pattern) is over 200 nm, 1 step photo etching process is applied and all patterns are formed in one step. 
         [0037]    However, as illustrated in example  FIG. 5B , if the pitch between patterns is less than 200 nm, 2 step photo etching process is applied, and patterns are formed over a plurality of steps, for example, two steps. If the pitch between patterns is below 200 nm and 1 step photo etching process is used, many errors may occur in patterns because of the limiting resolution. 
         [0038]    Thus, in the above case, a photo etching process may be executed once to form first patterns having pitch above 200 nm and the photo etching process is executed again on the first patterns to create new patterns. In this way, patterns with pitch below 200 nm can be easily manufactured. 
         [0039]    With contacts for a semiconductor device and a manufacturing method according to embodiments, by forming a conductive tube surrounding a contact plug and connected to a ground wire, over an outer circumferential edge of the contact plug which electrically connects a lower wire and an upper wire, noise generated from a contact plug cannot be emitted to the outside, and noise from outside cannot flow into the contact plug. Thus, embodiments can prevent various negative effects caused by noise on a semiconductor device which uses high frequency analog signals similar to a RF transmission device. 
         [0040]    It will be obvious and apparent to those skilled in the art that various modifications and variations can be made in the embodiments disclosed. Thus, it is intended that the disclosed embodiments cover the obvious and apparent modifications and variations, provided that they are within the scope of the appended claims and their equivalents.