Semiconductor integrated circuit device comprising conductive layers

Abstract: A signal interference prevention wiring (13, 14, 15) is disposed between two wirings (11, 12) which are arranged in parallel for transmitting a signal, and the signal interference prevention wiring (13, 14, 15) is held at a constant potential.

Description: This invention relates to a semiconductor integrated circuit device for preventing a signal interference between wirings. EP 0 246 458 discloses a module for packaging semiconductor integrated circuit chips on a base substrate. Here, in a semiconductor body there are provided several wiring layers in a multi-layered fashion. In each layer, there are provided adjacent signal lines, between which a grounded line is provided. Metal studs are formed for interconnecting the different wiring layers. One method is to perform an edging and then fill so-called "vias" with metal. Another way of forming the studs is to use stepped conductive vias at all locations, where an interconnection of the wiring layers is required. The studs thus serve as a through-contact between the individual layers, whilst a shielding of the signal lines is respectively only performed via the grounding line separately in each layer. There is no provision of achieving a shielding between signal wirings contained in different layers of the multi-layered structure. Likewise, JP-58053845 discloses a semiconductor integrated circuit, where a grounded electrode is provided between two structures of field effect transistors formed in the same semiconductor body. JP 57-104243 discloses a semiconductor device with a multi-layer wiring structure. A first and second wiring layer is separated by a polycrystal wiring, which is connected to ground. Thus, the two wiring layers are shielded. US-4,673,904 describes a support board or substrate for interconnecting various electronic components. Conductors are embedded within the substrate, and each conductor is provided with shielding to thereby eliminate any cross-coupled interference. Different types of shielding elements are suggested for wiring lines, all of which are provided in one plane. The shielding elements have various shapes, e.g. an I-shaped, U-shaped, or box-shaped. No mention is made of signal wiring lines in different layers. Furthermore, no mention is made of constant potential lines, but rather of whole shielding structures. Hereinafter, the problems with shielding in a multi-layer structure will be further explained with reference to Fig. 1. Recently, it has been strongly required to enhance the integration density of semiconductor integrated circuit devices, and the integration density has increased by further developing the element miniaturizing technique and multi-layered wiring technique. With the development of the element miniaturizing technique, the line width of the wiring and the distance between the wirings tend to be reduced. As the distance between the wirings becomes smaller, a signal interference between the wirings which can be neglected in the prior art becomes significant, thus making it difficult to effect the precise signal transmission. Fig. 1 is a cross sectional view showing the schematic construction of the conventional semiconductor integrated circuit device. As shown in Fig. 1, wiring 81 formed of a first-layered conductive layer and wiring 82 formed of a second-layered conductive layer are disposed in insulation layer 80. Parasitic capacitances C0, C1 and C2 are present between wirings 81 and 82. Capacitance C0 represents an equivalent parasitic capacitance existing along a straight line passing those portions of wirings 81 and 82 which face each other, and capacitances C1 and C2 each represent an equivalent parasitic capacitance existing along an outwardly curved line passing side portions of wirings 81 and 82. Generally, capacitances C0, C1 and C2 have the relation of C0 >> C1, C2. Assume now that different signals or voltages are transmitted along wirings 81 and 82. For example, an analog signal shown in the waveform diagram of Fig. 2(a) is transmitted along wiring 81 and a digital signal shown in Fig. 2(b) is transmitted along wiring 82. When the signals are transmitted along wirings 81 and 82, interference signals occur because of the presence of parasitic capacitances C0, C1 and C2. As a result, the analog signal is influenced by the digital signal and a distortion component is introduced into the analog signal as shown in Fig. 2(c). Therefore, it becomes impossible to correctly transmit the analog signal. Further, the semiconductor integrated circuit device having a miniaturized structure and a multi-layered wiring structure tends to be influenced by the peripheral wirings and subject to the signal interference caused therebetween, thus making it difficult to correctly transmit the signal. Accordingly, an object of this invention is to provide a semiconductor integrated circuit device in which the element miniaturization structure and multi-layered wiring structure can be attained without increasing the signal interference between wirings and a precise signal transmission can be effected. This object is solved by a semiconductor integrated circuit according to claim 1. Further advantageous embodiments and improvements of the invention are cited in the dependent claims. In the accompanying drawings Fig. 1 is a cross sectional view showing the schematic construction of the conventional semiconductor integrated circuit device; Fig. 2 is a waveform diagram of signals transmitted by means of the device shown in Fig. 1; Fig. 3 is across sectional view showing the schematic construction of a semiconductor integrated circuit device according to this invention; Fig. 4 is a cross sectional view showing the construction of an example of a semiconductor integrated circuit device not belonging to the invention; Fig. 5 is a cross sectional view showing the construction of an example of a semiconductor integrated circuit device not belonging to the invention; Fig. 6 is a cross sectional view showing the construction of a semiconductor integrated circuit device according to still another embodiment of this invention; Fig. 7 is a perspective view of part of the semiconductor integrated circuit device shown in Fig. 6; Fig. 8 is a perspective view of a modification of the semiconductor integrated circuit device shown in Fig. 6; Fig. 9 is a cross sectional view showing the construction of a semiconductor integrated circuit device according to another embodiment of this invention; Fig. 10 is a perspective view of part of the semiconductor integrated circuit device shown in Fig. 9; Fig. 11 is a perspective view of a modification of the semiconductor integrated circuit device shown in Fig. 9; and Fig. 12 is a cross sectional view of a modification of the semiconductor integrated circuit device shown in Fig. 9. There will now be described an embodiment of this invention with reference to the accompanying drawings. Fig. 3 is a cross sectional view showing the schematic construction of a semiconductor integrated circuit device according to this invention. As shown in Fig. 3, wiring 11 formed of a first-layered conductive layer and wiring 12 formed of a second-layered conductive layer are disposed in insulation layer 10. Wirings 11 and 12 are used to transmit different signals. Further, wiring 13 formed of the first-layered conductive layer and wiring 15 formed of the second-layered conductive layer and electrically connected to wiring 13 via contact hole 14 are arranged between wirings 11 and 12. Wirings 13 and 15 are held at a constant potential, for example, a grounded potential or power source potential. As described above, the wiring held at a constant potential is disposed between wirings 11 and 12 for transmitting different signals and therefore a capacitance corresponding to parasitic capacitance C0 shown in Fig. 1 will not be formed. That is, only capacitances corresponding to capacitances C1 and C2 occur as parasitic capacitances between wirings 11 and 12. In this case, as described before, the relation of C0 >> C1, C2 is generally set and the values of C1 and C2 can be suppressed to a sufficiently small value. As a result, influence of the signal interference between wirings 11 and 12 can be sufficiently suppressed owing to the presence of capacitances C1 and C2. Now, various embodiments of this invention will be explained. Fig. 4 is a cross sectional view showing the construction of part of an example of a CMOS semiconductor integrated circuit device not belonging to the invention. In Fig. 4, 21 denotes a P-type silicon substrate, 22 denotes an N-type well region formed in substrate 21, 23 denotes a field oxide film for element isolation, 24 and 25 denote the source and drain regions of N-channel MOS transistor 26 which are formed of N-type diffusion regions formed in the surface area of substrate 21, 27 denotes the gate electrode of N-channel MOS transistor 26 which is formed of a polycrystalline silicon layer, for example, 28 and 29 denote the source and drain regions of P-channel MOS transistor 30 which are formed of P-type diffusion regions formed in the surface area of N-type well region 22, 31 denotes the gate electrode of P-channel MOS transistor 30 which is formed of a polycrystalline silicon layer, 32 denotes an interlayer insulation layer formed of boron phospho-silicate glass (BPSG), phospho-silicate glass (PSG) or the like formed on the surface of substrate 21. Further, 33 denotes a drain wiring of N-channel MOS transistor 26 which is formed of aluminum, for example, in interlayer insulation layer 32, 34 denotes a source wiring of N-channel MOS transistor 26 which is formed of aluminum, for example, in interlayer insulation layer 32, 35 denotes a drain lead-out electrode formed of aluminum, for example, which is the same conductive material as drain wiring 33, for connecting drain wiring 33 and drain region 24 to each other, 36 denotes a source lead-out electrode formed of aluminum, for example, which is the same conductive material as source wiring 34, for connecting source wiring 34 and source region 25 to each other, 37 denotes a drain wiring of P-channel MOS transistor 30 which is formed of aluminum, for example, in interlayer insulation layer 32, 38 denotes a drain lead-out electrode formed of aluminum, for example, which is the same conductive material as drain wiring 37, for connecting drain region 28 and drain wiring 37 of P-channel MOS transistor 30 to each other. Wiring 39 formed of metal such as aluminium and held at a constant potential, for example, ground potential is disposed between wirings 33 and 37 formed in interlayer insulation layer 32. In Fig. 4, the source wiring and source lead-out electrode of P-channel MOS transistor 30 are omitted. Wirings such as wirings 33, 37 and 39 are formed to extend in a direction perpendicular to the drawing. With the integrated circuit device of this embodiment, drain wiring 33 of N-channel MOS transistor 26 corresponds to wiring 11 of Fig. 3 and drain wiring 37 of P-channel MOS transistor 30 corresponds to wiring 12 of Fig. 3. Further, wiring 39 disposed between drain wirings 33 and 37 corresonds to wiring 13 or 15 of Fig. 3. With the above construction, wiring 39 disposed between drain wirings 33 and 37 is held at the ground potential. Therefore, a parasitic capacitance occurring between drain wirings 33 and 37 can be suppressed to a minimum owing to the presence of wiring 39. As a result, even in a case where the distance between adjacent wirings becomes smaller as the dimensions of the of the wirings are reduced, influence by the signal interference occurring between drain wirings 33 and 37 can be suppressed to a minimum. Therefore, it becomes possible to correctly transmit signals along drain wirings 33 and 37. Fig. 5 is a cross sectional view showing the construction of part of an example of a CMOS semiconductor integrated circuit device not belonging to the invention. In the integrated circuit device of this embodiment, six electrodes 41 to 46 formed of aluminium, for example, are disposed in interlayer insulation layer 32 on field oxide film 23. Three wirings 41 to 43 among six wirings 41 to 46 are formed by depositing a first-layered aluminium layer on the entire surface of the semiconductor structure and then patterning the deposited aluminum layer and the remaining wirings 44 to 46 are formed by patterning a second-layered aluminum layer. Wiring 42 of first-layered three wirings 41 to 43 is disposed at a central position between wirings 41 and 43. Likewise, wiring 45 of second-layered three wirings 44 to 46 is disposed at a central position between wirings 44 and 46. Six wirings 41 to 46 are also formed to extend in a direction perpendicular to the drawing. Two wirings 42 and 45 which are disposed at the central position of the six wirings are used as wirings for connection with other circuits. The remaining four wirings 41, 43, 44 and 46 are held at a constant potential, for example, ground potential. Further, in the device of this embodiment, drain wirings 33 and 37 and source wiring 34 are formed in the same manner as wirings 44 to 46 by depositing the second-layered aluminum layer and then patterning the deposited aluminum layer. In the integrated circuit device of this embodiment, wiring 46 held at the ground potential is disposed between wiring 45 and drain wiring 33 of N-channel MOS transistor 26 and wiring 44 held at the ground potential is disposed between wiring 45 and drain wiring 37 of P-channel MOS transistor 30. As a result, even when signals are transmitted via drain wirings 33 and 37 and wiring 45, influence of the mutual interference of the signals can be suppressed to a minimum, making it possible to correctly transmit the signals by use of drain wirings 33 and 37 and wiring 45. Further, in the device of this embodiment, wiring 43 held at the ground potential is disposed between wiring 42 and drain lead-out electrode 35 of N-channel MOS transistor 26 and wiring 41 held at the ground potential is disposed between wiring 42 and drain lead-out electrode 38 of P-channel MOS transistor 30. As a result, influence of the signal interference between wiring 42 and drain lead-out electrode 35 and that of the signal interference between wiring 42 and drain lead-out electrode 38 can be suppressed to a minimum. In the above embodiment, wirings 41, 43, 44, 46 are all held at the ground potential. That is, the embodiment is made based on the fact that the signal interference between the wirings can be prevented by setting wirings 41, 43, 44, 46 at a constant potential. Therefore, it is easily understood that wirings 41, 43, 44, 46 may be set at a desired potential if it is constant. For example, they can be set at the power source potential instead of the ground potential. Further, it is not necessary to set all the wirings 41, 43, 44, 46 at the same constant potential. Fig. 6 is a cross sectional view showing the construction of part of a CMOS semiconductor integrated circuit device according to still another embodiment of this invention. In Fig. 6, portions which are the same as those of Fig. 5 are denoted by the same reference numerals and the explanation therefor is omitted. In the integrated circuit device of this embodiment, wiring 44 and wiring 41 formed on field oxide film 23 are disposed to fill a penetration hole formed in interlayer insulation film 32, and are electrically connected to each other by means of connection electrode 47 formed-of metal such as aluminum which is the same conductive material as wiring 44. Likewise, wiring 46 and wiring 43 formed on field oxide film 23 are disposed to fill a penetration hole formed in interlayer insulation film 32, and are electrically connected to each other by means of connection electrode 48 formed of metal such as aluminum which is the same conductive material as wiring 46. Fig. 7 discretely shows drain wirings 33 and 37, drain lead-out electrodes 35 and 38, wirings 41 to 46 and connection electrodes 47 and 48 of the device shown in Fig. 6. As shown in Fig. 7, wirings 41 and 44 and wirings 43 and 46 which are respectively connected via connection electrodes 47 and 48 are disposed to extend in the lengthwise direction of drain wiring 37 or 33 and wirings 42 and 45 which are disposed on both sides of the respective wirings and are formed in a wall configuration. The wirings formed in the wall configuration are disposed to separate drain wiring 33 or 37 from wirings 42 and 45. In the integrated circuit device of Fig. 6 having the multi-layered structure, the wirings of different layers held at a constant potential are electrically connected by means of the connection electrodes and the wirings are formed in a wall configuration. As a result, the signal run-around effect can be prevented and influence of the signal interference between the wirings disposed on both sides of the wall-shaped wirings can be suppressed to a minimum. Fig. 8 is a modification of the embodiment of Fig. 6, and discretely shows portions corresponding to drain wirings 33 and 37, drain lead-out electrodes 35 and 38, wirings 41 to 46 and connection electrodes 47 and 48 of the device shown in Fig. 6. In this modification, a desired number of holes 49 are formed in desired portions of connection electrodes 47 and 48. That is, in this modification, connection electrode 47 for connecting wirings 41 and 44 and connection electrode 48 for connecting wirings 43 and 46 are divided into a plurality of electrode portions, and portions in which neither connection electrode 47 nor connection electrode 48 is formed correspond to holes 49. Fig. 9 is a cross sectional view showing the construction of part of a CMOS semiconductor integrated circuit device according to another embodiment of this invention. In Fig. 9, portions which are the same as those of Fig. 6 are denoted by the same reference numerals and the explanation therefor is omitted. In the integrated circuit device of this embodiment, wirings 41 to 43 are formed of a first-layered metal such as aluminum, wirings 44 to 46 are formed of a second-layered metal such as aluminum, and three wirings 51 to 53 are formed in interlayer insulation film 32 by depositing a third-layered metal such as aluminum on the entire portion of the semiconductor structure and then patterning the metal layer. Like wirings 42 and 45, central wiring 52 among three wirings 51 to 53 is used as a transmission signal wiring for signal transmission with respect to another circuit. Further, wirings 51 and 53 are used as signal interference preventing wirings. Wirings 51 and 44 are electrically connected to each other by use of connection wiring 54 formed of the same conductive material as wiring 51 and formed to fill a penetration hole formed in interlayer insulation film 32. Likewise, wirings 53 and 46 are electrically connected to each other by use of connection wiring 55 formed of the same conductive material as wiring 53 and formed to fill a penetration hole formed in interlayer insulation film 32. Wirings 41, 44 and 51 which are connected to each other are kept at the ground potential, and wirings 43, 46 and 53 which are connected to each other are also kept at the ground potential. Also, in the device of this embodiment, it is possible to hold the potential of wirings 41, 44 and 51 and wirings 43, 46 and 53 at a constant potential which is different from the ground potential. Further, it is not necessary to hold the potential of wirings 41, 44 and 51 and that of wirings 43, 46 and 53 at the same potential. Fig. 10 discretely shows portions corresponding to drain wirings 33 and 37, drain lead-out electrodes 35 and 38, wirings 41 to 46, connection electrodes 47 and 48, wirings 51 to 53 and connection electrodes 54 and 55 of the device shown in Fig. 9. As shown in Fig. 10, wirings 41, 44 and 51 connected by means of connection electrodes 47 and 54 and wirings 43, 46 and 53 connected by means of connection electrodes 48 and 55 are disposed to extend in a longitudinal direction of drain wiring 37 or 33 and wirings 42, 45 and 52 and formed in a wall configuration. The wall-shaped wirings separate drain wiring 33 or 37 from wirings 42, 45 and 52. In this embodiment, influence of the signal interference between the wirings can be suppressed to a minimum in the same manner as in the integrated circuit device of Fig. 6. Fig. 11 is a modification of the embodiment of Fig. 9, and discretely shows portions corresponding to drain wirings 33 and 37, drain lead-out electrodes 35 and 38, wirings 41 to 46, connection electrodes 47 and 48, wirings 51 to 53 and connection electrodes 54 and 55 of the device shown in Fig. 9. In this modification, a desired number of holes 49 are formed in desired portions of connection electrodes 47, 48, 54 and 55. That is, in this modification, connection electrode 47 for connecting wirings 41 and 44, connection electrode 54 for connecting wirings 44 and 51, connection electrode 48 for connecting wirings 43 and 46 and connection electrode 55 for connecting wirings 46 and 53 are divided into a plurality of electrode portions, and portions in which none of connection electrodes 47, 54, 48 and 55 are formed correspond to holes 49. With the integrated circuit device of the above multi-layered structure, when the distance between wirings becomes smaller with the miniaturization of elements, signal interferences occur not only between the wirings of the same layer but also between the wirings of different layers. However, the signal run-around effect can be suppressed by connecting the wirings of different layers by use of the connection electrode held at a constant potential so as to form a wall configuration, and thus influence of the signal interference between the wirings disposed on both sides of the connection electrode can be suppressed to a minimum. As a result, signals can be correctly transmitted along the wirings. Fig. 12 shows another modification of the device shown in Fig. 9. In the device of this embodiment, when wirings 44 to 46 are formed by depositing the second-layered metal on the entire surface of the semiconductor structure and then patterning the deposited metal layer, wiring 56 is formed in opposition to wiring 44 with drain wiring 37 set at the center therebetween and wiring 57 is formed in opposition to wiring 46 with drain wiring 33 set at the center therebetween. Further, when wirings 51 and 53 are formed by depositing the third-layered metal on the entire surface of the semiconductor structure and then patterning the deposited metal layer, the wirings are formed to extend to wirings 56 and 57, and wirings 51 and 53 are electrically connected to wirings 56 and 57. With the construction described above, drain wiring 33, drain lead-out electrode 35, drain wiring 37 and drain lead-out electrode 38 are covered with the respective wirings 51, 53 held at the constant potential. As a result, influence of signal interferences between drain wiring 33, drain lead-out electrode 35, drain wiring 37 and drain lead-out electrode 38 and other respective wirings can be suppressed to a minimum. This invention is not limited to the above embodiments and various modifications can be made. For example, in the above embodiments, this invention is applied to a CMOS semiconductor integrated circuit device in which influence of a signal interference between the drain wirings or that between the drain wiring and the other wiring can be reduced. However, this invention can also be applied to various wirings in a semiconductor integrated circuit device in which the signal interference may occur. Further, in the above embodiments, each wiring is formed of metal such as aluminum which is a conductive material, but it can be formed of other conductive material such as polycrystalline silicon whose resistance is lowered. As described above, according to this invention, a semiconductor integrated circuit device can be provided in which the element miniaturization and multi-layered structure can be attained without increasing influence of a signal interference between the wirings and thus a signal can be correctly transmitted. Reference signs in the claims are intended for better understanding and shall not limit the socpe.

Claims: A semiconductor integrated circuit comprising: a) a semiconductor body (21); b) an insulation layer (10;32) formed on said semiconductor body (21); c) a first conductive wiring layer formed in said insulation layer (10;32), containing a first signal wiring line (11;42) for transmitting signals, and containing a first constant potential wiring line (13;41,43) held at a constant potential, where said first constant potential wiring line (13;41,43) is disposed to extend in the lengthwise direction of said first signal wiring line (11;42); d) a second conductive wiring layer formed in said insulation layer (10;32), arranged above said first conductive wiring layer, containing a second signal wiring line (12;37,33) for transmitting signals parallel to said first signal wiring line (11;42) of said first conductive wiring layer, and containing a second constant potential wiring line (15;44,46) held at a constant potential, where said second constant potential wiring line (15;44,46) is disposed to extend in the lengthwise direction of said second signal wiring line (12;37,33) and vertically above said first constant potential wiring line (13;41,43) of said first conductive layer; wherein e) said first and second signal wiring lines (11;42;12;37,33) are used to transmit different signals, and f) said first constant potential wiring line (13;41,43) of said first conductive wiring layer and said second constant potential wiring line (15;44,46) of said second conductive wiring layer are electrically connected vertically via a connection electrode (14;47,48) disposed to extend in the lengthwise direction of the signal wiring (11,12;33,37,42), thereby forming a wall configuration, and g) said wall configuration is arranged between said first signal wiring line (11;42) of the first conductive wiring layer and said second signal wiring line (12;37,33) of the second conductive wiring layer. A semiconductor integrated circuit according to claim 1, characterized in that said constant potential wiring lines (13, 15; 41, 43, 44, 46) and said connection electrode (14;47,48) are held at the ground potential. A semiconductor integrated circuit according to claim 1, characterized in that said constant potential wiring lines (13,15;41,43,44,46) and said connection electrode (14;47,48) are held at a power source potential. A semiconductor integrated circuit according to one of claims 1 to 3, characterized by a desired number of holes (49) being formed in desired portions of said connection electrode (14;47,48). A semiconductor integrated circuit according to one of claims 1 to 4, characterized by a third conductive wiring layer being arranged above said second conductive wiring layer, containing a third signal wiring line (52) and containing a third constant potential wiring line (51, 53), which is arranged vertically above said second constant potential wiring line (15; 44, 46) of said second conductive wiring layer and electrically connected vertically to said second constant potential wiring line (15; 44, 46) of said second conductive wiring layer via connection electrodes (54, 55), the wiring lines of the third conductive wiring layer being parallel to the wiring lines of the second conductive layer. A semiconductor integrated circuit according to claim 5, characterized by a further constant potential wiring line (56, 57) in said second conductive wiring layer being disposed with respect to said second constant potential wiring line (44, 46) so that said second signal wiring line (33, 37) of said second conductive wiring layer is set at the center therebetween, and said further constant potential wiring line (56, 57) being electrically connected to said third constant potential wiring line (51, 53) of said third conductive wiring layer.

Inventors: GOTO JUNKEI, IIDA TETSUYA, TAKAKURA HIROSHI, GOTO, JUNKEI, IIDA, TETSUYA, TAKAKURA, HIROSHI
Applicants: TOSHIBA KK, KABUSHIKI KAISHA TOSHIBA
Application year: 1989
Main classification: H01L23
IPC codes: H01L29, H01L27, H01L23, H01L21