JP2004282094A - Semiconductor integrated circuit device, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique that can increase the threshold potential of parasitic MOS of a semiconductor integrated circuit device having a high breakdown voltage MISFET. <P>SOLUTION: A silicon oxide film 5c is formed on a field oxide film 4 of the high breakdown voltage MISFET formation areas HN and HP. As a result of that, it is possible to increase the threshold potential of parasitic MOS formed on this field oxide film 4. Further, while a polycrystalline silicon film 111 that becomes a low breakdown voltage MISFET gate electrode is formed on a high breakdown voltage MISFET gate electrode FG, impurities for adjusting the low breakdown voltage MISFET threshold are implanted. As a result, the impurities will remain inside the high breakdown voltage MISFET gate electrode FG, suppressing the occurrence of an NBT phenomenon. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a semiconductor integrated circuit device and a method of manufacturing the same, and more particularly to a semiconductor integrated circuit device in which a high voltage MISFET (Metal Insulator Semiconductor Field Effect Transistor) and a low voltage MISFET are formed on the same semiconductor substrate, and a method of manufacturing the same. It is.

  The high breakdown voltage MISFET is used for a driver of a liquid crystal display device, a motor control driver for performing high current control, a nonvolatile memory that requires a high voltage for a program, and the like.

  In this high-breakdown-voltage MISFET, various devices have been devised to increase the withstand voltage in addition to forming a thick gate insulating film.

  For example, Japanese Patent Application Laid-Open No. H11-177047 discloses that among a plurality of types of field effect transistors having different thicknesses of the gate insulating film, the gate insulating film 10 of one transistor is formed by a laminated film of the thermal oxide film 8 and the deposited film 9. A technique for forming is described (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2000-68385 discloses that an electric field relaxation region NW (FD) of a high-breakdown-voltage NMOS transistor includes a well region NW of a low-breakdown-voltage PMOS transistor and a channel stopper NW of a well HNW region of a high-breakdown-voltage PMOS transistor. A technique for forming simultaneously with (CS) is described (see Patent Document 2).
JP-A-11-177047 JP-A-2000-68385

  The present inventors studied improving the drain withstand voltage by providing electric field relaxation layers 9 and 8 around the source and drain regions 17 and 18 of the high withstand voltage MISFET (Qn2, Qp2) as shown in FIG. .

  However, in the structure of the MISFET shown in FIG. 40, since the gate insulating film 5 under the gate electrode FG is thin, the gate insulating film is cut off at its end, and a problem arises that the withstand voltage cannot be secured. Further, since the electric field relaxation layers 9 and 8 are separated at both ends of the source and drain regions 17 and 18, electric field concentration easily occurs at the boundary between the electric field relaxation layer and the source and drain regions. As a result, problems such as a decrease in drain withstand voltage and a decrease in electrostatic breakdown strength are caused.

  Among these problems, in order to reduce the electric field concentration at the boundary between the electric field relaxation layer and the source / drain regions, a structure as shown in FIG. However, the problem of reduction in breakdown voltage due to cutting of the gate insulating film 5 at the end of the gate electrode has not been solved.

  On the other hand, as shown in FIG. 42, it has been considered to improve the breakdown voltage by providing a field oxide film 4a at the end of the gate electrode FG. In this case, however, the electric field relaxation layers 9 and 8 and the source and drain regions 17 have been studied. , 18 could not be reduced.

  The functions and the like of each part in FIGS. 40 to 42 will be clarified by the embodiment of the present invention, and thus detailed description will be omitted.

  An object of the present invention is to provide a structure of a miniaturized MISFET having a high breakdown voltage and a method of manufacturing the same.

  Another object of the present invention is to provide a structure of a high-breakdown-voltage MISFET which suppresses the influence of a parasitic MOS and a method of manufacturing the same.

  Another object of the present invention is to provide a structure of a high-performance and high-breakdown-voltage MISFET and a method of manufacturing the same.

  The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application.

  According to a method of manufacturing a semiconductor integrated circuit device of the present invention, a step of forming a first insulating film between first MISFET forming regions and a second MISFET forming region; and forming a second and a third insulating film on the semiconductor substrate surface between the first insulating films. Forming an insulating film, forming a first conductive film on the third insulating film in the second region where the second MISFET is formed, and forming third and second insulating films in the first region where the first MISFET is formed. Forming a fourth insulating film in the first region after removing the film, and forming a second conductive film on the fourth insulating film; The third insulating film remains.

  According to the method of manufacturing a semiconductor integrated circuit device of the present invention, a step of forming a first insulating film between a first MISFET formation region and a second MISFET formation region; and forming a first semiconductor region in a first region where the first MISFET is formed. Forming a second semiconductor region in the second region where the second MISFET is formed; forming second and third insulating films in the first and second regions; and forming third and third insulating films in the first region. Removing the second insulating film, removing a part of the second and third insulating films on the second semiconductor region in the second region to form a first opening, and forming a third opening in the second region. A step of forming a first conductive film serving as a gate electrode of the second MISFET on the insulating film, a step of forming a fourth insulating film in the first region, and a step of forming a second conductive film serving as a gate electrode of the first MISFET on the fourth insulating film Forming a conductive film and before the first region A third semiconductor region having a conductivity type opposite to that of the first semiconductor region is formed on both sides of the gate electrode, and a fourth semiconductor region having the same conductivity type as the second semiconductor region is formed below the first opening in the second region. Introducing an impurity into the surface of the semiconductor substrate to form a semiconductor region.

  A method of manufacturing a semiconductor integrated circuit device according to the present invention includes a step of forming a first insulating film in a first region where a first MISFET is formed and a second region where a second MISFET is formed; Depositing a first conductive film on the first insulating film, removing the first insulating film and the first conductive film in the first region, and removing the first region on the semiconductor substrate Forming a second insulating film, depositing a second conductive film on the first and second regions, and providing the first and second regions with energy that reaches a substrate in the first region. Implanting impurities from above the second conductive film.

  A semiconductor integrated circuit device according to the present invention includes a first insulating film located between a first MISFET forming region in a first region where a first MISFET is formed and a second insulating film located between a second MISFET forming region in a second region where a second MISFET is formed. A second insulating film formed in the two regions, a third insulating film formed on the first insulating film in the second region and on the second insulating film, and a first conductive film formed on the third insulating film in the second region. A film, a fourth insulating film formed in the first region, and a second conductive film formed on the fourth insulating film in the first region.

  A semiconductor integrated circuit device according to the present invention includes a second semiconductor region formed in the semiconductor substrate in the second region and having a conductivity type opposite to a first semiconductor region formed in the first region; A third insulating film formed on the first and second insulating films on the second semiconductor region in the region, and a third insulating film formed on the first and second insulating films; And a fourth semiconductor region of the conductivity type formed in the second semiconductor region.

  The semiconductor integrated circuit device according to the present invention is a semiconductor integrated circuit device comprising: a first insulating film located between each MISFET forming region of a first region where a first MISFET is formed and a second region where a second MISFET is formed; A second insulating film formed on a substrate surface, a third insulating film formed on a second region, a first conductive film on the third insulating film in a second region, and the semiconductor substrate on a first region. A fourth insulating film formed on the surface; and a second conductive film formed on the fourth insulating film in the first region.

  The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

  According to the present invention, since the silicon oxide film 5c (third insulating film) is formed on the field oxide film 4 and the silicon oxide film 104 (first insulating film) formed in the trench, the field oxide film 4 and the like are formed. Can increase the threshold potential of the parasitic MOS formed on the substrate.

  Further, according to the present invention, when the conductive film (second conductive film) constituting the gate electrode of the low-breakdown-voltage MISFET is present on the gate electrode (first conductive film) of the high-breakdown-voltage MISFET, the threshold voltage of the low-breakdown-voltage MISFET is reduced. Since the adjustment impurity is implanted, the occurrence of the NBT phenomenon can be suppressed.

  Further, according to the present invention, it is possible to form a miniaturized high-performance semiconductor integrated circuit device.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In principle, components having the same function are denoted by the same reference numerals in all drawings for describing the embodiments, and the description thereof will not be repeated.

(Embodiment 1)
A method for manufacturing the semiconductor integrated circuit device according to the present embodiment will be described in the order of steps with reference to FIGS.

  First, as shown in FIG. 1, a semiconductor substrate 1 made of p-type single crystal silicon is prepared. The semiconductor substrate 1 includes a region LN where the low-breakdown-voltage n-channel MISFET Qn1 is formed, a region LP where the low-breakdown-voltage p-channel MISFET Qp1 is formed, a region HN where the high-breakdown-voltage n-channel MISFET Qn2 is formed, and a high-breakdown-voltage p-channel type. There is a region HP where the MISFET Qp2 is formed and a region CA where the capacitive element C is formed.

  A silicon oxide film 2 is formed by oxidizing the surface of the semiconductor substrate 1. Subsequently, after selectively forming the silicon nitride film 3 on the silicon oxide film, as shown in FIG. 2, the silicon nitride film 3 is used as a mask to perform a thermal oxidation process to form a field having a thickness of about 300 nm. An oxide film 4 (first insulating film) is formed. The field oxide film 4 separates the MISFET formation regions LN, LP, HN, and HP from each other. Here, in the high-breakdown-voltage MISFETs Qn2 and Qp2 formation region (HN, HP), a field oxide film 4a is formed below both ends of the gate electrode FG which will be described later. This field oxide film 4a is formed to improve the breakdown voltage of the high breakdown voltage MISFETs Qn2 and Qp2. Subsequently, the silicon nitride film 3 on the semiconductor substrate 1 is removed by wet etching using hot phosphoric acid.

  Next, as shown in FIG. 3, a resist film R1 is formed on the high breakdown voltage n-channel MISFET formation region HN and the capacitor formation region CA. Next, phosphorus is ion-implanted using the resist film R1 as a mask. The implantation energy of the ions at this time is also lower than the field oxide films 4 and 4a of the low-breakdown-voltage n-channel MISFET formation region LN, the low-breakdown-voltage p-channel MISFET formation region LP, and the high-breakdown-voltage p-channel MISFET formation region HP. Is set to be entered. Next, the resist film R1 is removed (FIG. 4).

Next, as shown in FIG. 4, a resist film R2 is formed on the low-breakdown-voltage n-channel MISFET formation region LN, the low-breakdown-voltage p-channel MISFET formation region LP, and the high-breakdown-voltage p-channel MISFET formation region HP. Next, boron is ion-implanted using the resist film R1 as a mask. The ion implantation energy at this time is set so that boron is also implanted under the field oxide films 4 and 4a in the high-breakdown-voltage n-channel MISFET formation region HN and the capacitor element formation region CA.
Next, after removing the resist film R2, a heat treatment at 1200 ° C. is performed to form an n-type isolation region 6 (n-type well 6) and a p-type well 7 (FIG. 5). In the present embodiment, the p-type well 7 is formed below the field oxide films 4 and 4a in the capacitive element formation area CA, but the n-type well 6 may be formed.

  Next, as shown in FIG. 5, a resist film R3 is formed on a region other than the vicinity of the source and drain regions of the high-breakdown-voltage p-channel MISFET Qp2. Next, boron is ion-implanted using the resist film R3 as a mask. The ion implantation energy at this time is set so that boron is also implanted under the field oxide films 4 and 4a in the high-breakdown-voltage p-channel MISFET formation region HP.

  Next, the resist film R3 is removed, and a resist film R4 is formed on a region other than the vicinity of the source and drain regions of the high-breakdown-voltage n-channel MISFET Qn2 as shown in FIG. Next, phosphorus is ion-implanted using the resist film R4 as a mask. The ion implantation energy at this time is set so that phosphorus is also implanted under the field oxide films 4 and 4a in the high-breakdown-voltage n-channel MISFET formation region HN.

  Next, by removing the resist film R4 and performing a heat treatment, the p-type electric field relaxation layer 8 is formed near the source and drain regions of the high-breakdown-voltage n-channel MISFET Qn2 near the source and drain regions of the high-breakdown-voltage p-channel MISFET Qp2. , An n-type electric field relaxation layer 9 is formed.

  Next, as shown in FIG. 7, a resist film R5 is formed on a region other than the low breakdown voltage p-channel MISFET Qp1 formation region LP. Next, using this resist film R5 as a mask, phosphorus is ion-implanted and heat treatment is performed to form an n-type well 9b. At the time of this ion implantation, the n-type well 9c may be formed also by ion implantation of phosphorus under the field oxide film 4 in the high-breakdown-voltage p-channel MISFET formation region HP (FIG. 8). The n-type well 9c is formed to increase the threshold potential Vt of a parasitic MOS (Metal Oxide Semiconductor) formed on the field oxide film 4. In particular, the n-type isolation region 6 and the p-type well 7 are set such that the impurity concentration becomes lower as approaching the surface of the semiconductor substrate 1 in order to secure the breakdown voltage of the high breakdown voltage MISFETs Qn2 and Qp2 formed on the main surface. Have been. As a result, the threshold potential Vt of the parasitic MOS tends to decrease. Here, the parasitic MOS means that when the first layer wiring is formed on the field oxide film 4 via the interlayer insulating film SZ (see FIG. 22B), the field oxide film 4 and the interlayer insulating film SZ are gated. It refers to an undesired MOS having an insulating film and a first layer wiring as a gate electrode. When the threshold potential Vt of the MOS is low, current easily flows below the field oxide film 4.

  Next, as shown in FIG. 8, a resist film R6 is formed on a region other than the low breakdown voltage n-channel MISFET Qn1 formation region LN. Next, using this resist film R6 as a mask, boron is ion-implanted and heat treatment is performed to form a p-type well 8b (FIG. 9). At the time of this ion implantation, the p-type well 8c may be formed also by implanting boron below the field oxide film 4 in the high breakdown voltage n-channel MISFET formation region HN. The p-type well 8c is also formed to increase the threshold potential Vt of the parasitic MOS formed on the field oxide film 4, similarly to the n-type well 9c.

  Next, as shown in FIG. 9, impurities are ion-implanted on the semiconductor substrate 1. This impurity is used for adjusting the threshold potential Vt of the high-breakdown-voltage MISFETs Qn2 and Qp2. In FIG. 9, ion implantation is performed on the entire surface of the semiconductor substrate 1. However, desired impurities are ion-implanted into the high-breakdown-voltage n-channel MISFET formation region HN and the high-breakdown-voltage p-channel MISFET formation region HP, respectively. The threshold voltage Vt of the high-breakdown-voltage MISFETs Qn2 and Qp2 may be adjusted.

  Next, after the thin silicon oxide film 2 on the surface of the semiconductor substrate 1 is removed, a silicon oxide film 5a (second insulating film) to be a part of the gate insulating film 5 is formed by thermal oxidation. Next, a silicon oxide film 5b (third insulating film) is deposited on the semiconductor substrate 1 by low pressure chemical vapor deposition (LPCVD). The thickness of the silicon oxide film 5b is set to be larger than the thickness of the silicon oxide film 5a.

  Then, as shown in FIG. 11A, the gate electrode formation scheduled regions of the high breakdown voltage MISFETs Qn2 and Qp2, the high breakdown voltage n-channel MISFET formation region HN, the high breakdown voltage p-channel MISFET formation region HP, and the capacitor element formation region CA The silicon oxide film 5b is patterned so that the silicon oxide film 5b remains on the field oxide film 4. Here, the field oxide film 4 on the low breakdown voltage n-channel MISFET formation region LN and the low breakdown voltage p-channel MISFET formation region LP (the boundary between the high breakdown voltage portion and the low breakdown voltage portion; in the drawing, the p-channel MISFET formation region LP (Except for the field oxide film 4 on the boundary between the high-breakdown-voltage n-channel MISFET formation region HN and the low-breakdown-voltage p-channel MISFET formation region LP except for the field oxide film 4 on the boundary with the silicon oxide film 5b) Is not allowed to remain. The reason why the silicon oxide film 5b is left on the field oxide film 4 in the capacitive element formation region CA is to reduce the parasitic capacitance with the substrate (p-type well 7).

  As shown in FIG. 11, the field oxide film 4 on these regions (LN, LP) is formed with a width of 1 μm or less for high integration of elements (MISFETs Qn1, Qn2, etc.) formed in the low breakdown voltage portion. Is done. Therefore, it is difficult to perform patterning so that the silicon oxide film 5b remains on the narrow field oxide film 4 formed in the low withstand voltage portion, and a mask shift easily occurs. When this mask shift occurs, the silicon oxide film 5b may extend over the source / drain formation regions and the gate electrode formation regions of the MISFETs Qn1 and Qn2. As a result, there arises a problem that the widths of the source and drain regions and the gate electrodes of the MISFETs Qn1 and Qn2 are reduced. To avoid such a problem, the silicon oxide film 5b on the field oxide film 4 in the low breakdown voltage portion is removed.

  Further, as shown in FIG. 11B, a semiconductor region 9d or a semiconductor region (second semiconductor region) for supplying a power supply potential or a ground potential (fixed potential) to the n-type isolation region 6 and the p-type well 7 is provided. The silicon oxide film 5b on the (four semiconductor regions) is also removed (the opening described in the claims). The semiconductor region 9d or 8d has the same conductivity type as the n-type isolation region 6 or the p-type well 7 in which the semiconductor region 9d or 8d is formed. The semiconductor region 9d or 8d is formed in at least one place inside the n-type isolation region 6 and the p-type well 7, to which a power supply potential and a ground potential are applied, respectively.

  In addition, since the silicon oxide film 5b on the source and drain regions of the MISFETs Qn1, Qp1, Qp2, and Qn2 has been removed, it is possible to simultaneously ion-implant regions of the same conductivity type among these regions. The number can be reduced, and the number of steps can be reduced.

  Next, the film quality of the silicon oxide film 5b is improved by performing a heat treatment at 900 ° C., preferably 1000 ° C. or higher. The silicon oxide film after the heat treatment is set to 5c (FIG. 12). The silicon oxide film 5 c on the region where the gate electrode of the high breakdown voltage MISFETs Qn 2 and Qp 2 is to be formed becomes a part of the gate insulating film 5. That is, the silicon oxide film 5c and the silicon oxide film 5a constitute a gate insulating film of the high-breakdown-voltage MISFETs Qn2 and Qp2. Thus, by performing the high-temperature heat treatment on the silicon oxide film 5b, the film quality of the silicon oxide film 5b can be made equal to the thermal oxide film. When the silicon oxide film 5b is used as a gate insulating film without being subjected to a heat treatment, the silicon oxide film 5b contains many trap levels, which makes it difficult to adjust the threshold potential Vt.

  In addition, a parasitic MOS formed on these regions by the high-breakdown-voltage n-channel MISFET formation region HN, the high-breakdown-voltage p-channel MISFET formation region HP, and the silicon oxide film 5c on the field oxide film 4 in the capacitive element formation region CA. Can be increased.

  In addition, since the silicon oxide film 5b is formed by LPCVD, the etching ratio with respect to the field oxide films 4 and 4a, which are thermal oxide films, can be increased, so that the surface of the field oxide films 4 and 4a is hardly etched. The silicon oxide film 5b can be etched. As a result, the thickness of the field oxide film 4 can be ensured, and the threshold potential Vt of the parasitic MOS formed thereon can be kept large.

  Next, as shown in FIG. 13, a polycrystalline silicon film (polysilicon) 10 is deposited on the semiconductor substrate 1 by a CVD method. Polycrystalline silicon may be reacted in an atmosphere containing phosphorus to make the polycrystalline silicon film 10 contain phosphorus impurities. After the formation of the polycrystalline silicon film 10, phosphorus may be doped.

  Next, as shown in FIG. 14A, the polycrystalline silicon film 10 is patterned so as to remain on the gate insulating films 5 (5a, 5c) of the high-breakdown-voltage MISFETs Qn2, Qp2. This polycrystalline silicon film becomes the gate electrode FG (first conductive film) of the high-breakdown-voltage MISFETs Qn2 and Qp2. At this time, the polycrystalline silicon film 10 is also left on the silicon oxide film 5c in the capacitive element formation region CA (third region). This polycrystalline silicon film 10 becomes the lower electrode LE of the capacitive element C. Although the gate electrodes of the high-breakdown-voltage MISFETs Qn2 and Qp2 are formed of the polycrystalline silicon film 10 (FG) here, the gate electrodes of the high-breakdown-voltage MISFETs Qn2 and Qp2 will be described later in detail. 11 (SG). FIGS. 14B and 16B are explanatory diagrams of a case where the gate electrodes of the high-breakdown-voltage MISFETs Qn2 and Qp2 are formed of the polycrystalline silicon film 11. FIG.

  Next, as shown in FIG. 15, impurities are ion-implanted on the semiconductor substrate 1. This impurity is used to adjust the threshold potential Vt of the low-breakdown-voltage MISFETs Qn1 and Qp1. The threshold voltage Vt of the low-breakdown-voltage MISFETs Qn1 and Qp1 may be adjusted by ion-implanting desired impurities into the low-breakdown-voltage n-channel MISFET formation region LN and the low-breakdown-voltage p-channel MISFET formation region LP.

  Next, as shown in FIG. 16A, after removing the thin silicon oxide film 5a on the low-breakdown-voltage n-channel MISFET formation region LN and the low-breakdown-voltage p-channel MISFET formation region LP, the low-breakdown-voltage MISFETs Qn1 and Qp1 are removed. A silicon oxide film to be the gate insulating film 5d (fourth insulating film) is formed by thermal oxidation. At this time, the gate electrodes FG of the high breakdown voltage MISFETs Qn2 and Qp2 are also slightly oxidized. Also, the surface of the lower electrode LE is slightly oxidized, and a silicon oxide film (not shown) is formed. This silicon oxide film becomes a capacitive insulating film of the capacitive element C. In order to increase the reliability of the capacitor C, a silicon nitride film is formed in advance on the polycrystalline silicon film 10 after the polycrystalline silicon film 10 serving as the lower electrode LE is deposited. Good.

  As described above, in the above-described process, the removal of the thin oxide film on the surface of the semiconductor substrate, such as the removal of the silicon oxide film 2 and the silicon oxide film 5a, is repeatedly performed. The surface is also etched and the film thickness decreases. However, according to the present embodiment, the thickness can be compensated for by the silicon oxide film 5c on the field oxide film 4, so that the threshold potential Vt of the parasitic MOS formed thereon can be maintained high, and Parasitics under the field oxide film due to wiring connecting them can be suppressed. Of course, the threshold potential Vt of the parasitic MOS needs to be higher than the voltage applied to the element. Here, the voltage applied to the MISFETs Qn1 and Qp1 in the low withstand voltage section is, for example, about 3.6V, and the voltage applied to the MISFETs Qn2, Qp2 in the high withstand voltage section is, for example, about 20V. Note that it is more effective if the thickness of the silicon oxide film 5c is larger than that of the silicon oxide films 2 and 5d.

  Next, a polycrystalline silicon film 11 is deposited on the semiconductor substrate 1 by a CVD method. Next, the polycrystalline silicon film 11 is patterned so as to remain on the gate insulating film 5d of the low-breakdown-voltage MISFETs Qn1 and Qp1. This polycrystalline silicon film 11 becomes a gate electrode SG (second conductive film) of the low-breakdown-voltage MISFETs Qn1 and Qp1. At this time, the polycrystalline silicon film 11 is also left on the capacitive insulating film (not shown) on the lower electrode LE in the capacitive element formation area CA. This polycrystalline silicon film 11 becomes the upper electrode UE of the capacitive element C. After forming a tungsten silicide layer on the surface of the polycrystalline silicon film 11, the gate electrode SG may be formed by patterning. This tungsten silicide layer is formed by depositing a metal film such as a tungsten film on the polycrystalline silicon film 11 and performing a heat treatment. This silicide layer is formed to reduce the resistance of the gate electrode SG.

  Next, the source and drain regions of the low-breakdown-voltage MISFETs Qn1 and Qp1 and the high-breakdown-voltage MISFETs Qn2 and Qp2 are formed. Hereinafter, formation of these source and drain regions will be described.

  As shown in FIG. 17, a resist film R7 is formed on the semiconductor substrate 1, and a hole is formed in the low breakdown voltage n-channel MISFET formation region LN. Next, phosphorus is ion-implanted using the resist film R7 and the gate electrode SG of the low-breakdown-voltage MISFET Qn1 as a mask.

  Next, after removing the resist film R7, as shown in FIG. 18, a resist film R8 is formed on the semiconductor substrate 1, and a hole is formed in the low breakdown voltage p-channel MISFET formation region LP. Next, boron is ion-implanted using the resist film R8 and the gate electrode SG of the low-breakdown-voltage MISFET Qp1 as a mask.

Next, after removing the resist film R8, the implanted phosphorus and boron are thermally diffused on both sides of the gate electrodes SG of the low-breakdown-voltage MISFETs Qn1 and Qn2, respectively, so that the p ⁻ -type semiconductor region 14 and the n ⁻ -type semiconductor region 13 are formed. Is formed (FIG. 19).

  Next, as shown in FIG. 19, after depositing a silicon oxide film on the semiconductor substrate 1, by etching back, a sidewall film 16s is formed on the side wall of the gate electrode SG of the low-breakdown-voltage MISFETs Qn1 and Qn2.

Next, as shown in FIG. 20, a resist film R9 is formed on the gate electrode FG of the low-breakdown-voltage p-channel MISFET formation region LP, the high-breakdown-voltage p-channel MISFET formation region HP, and the high-breakdown-voltage n-channel MISFET Qn2. Next, arsenic (As) is ion-implanted using the resist film R9 as a mask, annealed, and activated to thereby activate both sides of the gate electrodes (SG, FG) of the low-breakdown-voltage n-channel MISFET Qn1 and the high-breakdown-voltage n-channel MISFET Qn2. Then, an n ⁺ type semiconductor region 17 (source and drain regions) is formed (FIG. 21).

Next, as shown in FIG. 21, a resist film R10 is formed on the gate electrode FG of the low-breakdown-voltage n-channel MISFET formation region LN, the high-breakdown-voltage n-channel MISFET formation region HN, and the high-breakdown-voltage p-channel MISFET Qp2. Then, using the resist film R10 as a mask, boron is ion-implanted, annealed, and activated to form p on both sides of the gate electrodes (SG, FG) of the low-breakdown-voltage p-channel MISFET Qp1 and the high-breakdown-voltage p-channel MISFET Qp2. ^{A +} type semiconductor region 18 (source and drain regions) is formed (FIG. 22A). At this time, boron is not implanted below the field oxide films 4, 4a and the silicon oxide film 5c.

  Here, the resist films R7 and R8 are left on the gate electrodes FG of the high-breakdown-voltage MISFETs Qn2 and Qp2 in order to prevent the gate electrodes FG from being charged by ion implantation and causing dielectric breakdown of the gate oxide films. is there.

In the steps up to this point, the source and the drain (the n ⁻ type semiconductor region 13 and the n ⁺ type semiconductor region 17 and the p ⁻ type) having the LDD (Lightly Doped Drain) structure are formed in the low breakdown voltage portions (LN, LP (first region)). Low-breakdown-voltage MISFETs Qn1 and Qp1 (first MISFET) each including the semiconductor region 14 and the p ⁺ type semiconductor region 18) are formed. Further, high-breakdown-voltage MISFETs Qn2 and Qp2 (second MISFET) are formed in the high-breakdown-voltage portion (HN, HP (second region)).

  Next, an interlayer insulating film SZ made of a silicon oxide film or the like is deposited on the MISFETs Qn1, Qn2, Qp1, Qp2 and the capacitor C, and a contact hole (not shown) is formed on a desired region. The first layer wiring M1 is formed on the interlayer insulating film including the inside of the hole (see FIG. 22B). Further, a multilayer wiring can be formed on the first-layer wiring M1 by repeating formation of an interlayer insulating film and a metal for wiring. In addition, a protective film that covers the entire chip is formed on the uppermost layer wiring, but its drawing and detailed description are omitted.

  In the present embodiment, the gate electrodes SG of the low-breakdown-voltage MISFETs Qn1 and Qp1 are formed by the polycrystalline silicon film 11, and the gate electrodes FG of the high-breakdown-voltage MISFETs Qn2 and Qp2 are formed by the polycrystalline silicon film 10. The gate electrode can be formed of the polycrystalline silicon film 11.

  That is, as shown in FIG. 14B, after the polycrystalline silicon film 10 of the present embodiment is deposited (see FIG. 13), the polycrystalline silicon film 10 is formed only on the silicon oxide film 5c in the capacitive element formation region CA. The remaining electrode LE is formed.

  Next, impurities are ion-implanted on the semiconductor substrate 1 in order to adjust the threshold potential Vt of the low-breakdown-voltage MISFETs Qn1 and Qp1 (see FIG. 15). Next, as shown in FIG. 16B, the thin silicon oxide film 5a on the low-breakdown-voltage n-channel MISFET formation region LN and the low-breakdown-voltage p-channel MISFET formation region LP is removed, and the gate insulation of the low-breakdown-voltage MISFETs Qn1 and Qp1 is removed. A silicon oxide film to be the film 5d is formed by thermal oxidation.

  Next, a polycrystalline silicon film 11 is deposited on the semiconductor substrate 1 by a CVD method, and the polycrystalline silicon film 11 is deposited on the gate insulating films 5 (5a, 5c) of the high-breakdown-voltage MISFETs Qn2 and Qp2 and the low-breakdown-voltage MISFETs Qn1 and Qp1. Patterning is performed so as to remain on the gate insulating film 5d.

  According to the above steps, the gate electrodes of the low-breakdown-voltage MISFETs Qn1 and Qp1 and the high-breakdown-voltage MISFETs Qn2 and Qp2 can be formed simultaneously by the polycrystalline silicon film 11 (SG). The gate electrodes of the low-breakdown-voltage MISFETs Qn1 and Qp1 and the high-breakdown-voltage MISFETs Qn2 and Qp2 can be formed of the polycrystalline silicon film 10 (FG). However, in the subsequent steps of depositing and patterning the polycrystalline silicon film 11, The polycrystalline silicon film 11 remains on the side wall of the gate electrode and affects the characteristics of the MISFET. Therefore, it is desirable to form these gate electrodes with the polycrystalline silicon film 11.

(Embodiment 2)
In the first embodiment, the field oxide film 4 is used for separation between the MISFET formation regions LN, LP, HN, and HP. However, the separation may be performed using an oxide film embedded in the trench.

  A method of manufacturing a semiconductor integrated circuit device according to the present embodiment will be described in the order of steps with reference to FIGS.

  First, as shown in FIG. 23, a semiconductor substrate 1 made of p-type single crystal silicon is prepared. The semiconductor substrate 1 includes a region LN where a low-breakdown-voltage n-channel MISFET Qn1 is formed, a region LP where a low-breakdown-voltage p-channel MISFET Qp1 is formed, a region HN where a high-breakdown-voltage n-channel MISFET Qn2 is formed, and a high-breakdown-voltage p-channel type. There is a region HP where the MISFET Qp2 is formed.

  A silicon oxide film 2 is formed by oxidizing the surface of the semiconductor substrate 1. Subsequently, after selectively forming a silicon nitride film 3 on the silicon oxide film, as shown in FIG. 24, using the silicon nitride film 3 as a mask, the semiconductor substrate 1 is etched to form a groove having a depth of about 300 nm. Form U. Here, in the high-breakdown-voltage MISFET Qn2, Qp2 formation region (HN, HP), a groove is also formed below both ends of a gate electrode described later.

  Next, the substrate 1 is thermally oxidized at about 1000 ° C. to form a thin silicon oxide film (not shown) having a thickness of about 10 nm on the inner wall of the groove. This silicon oxide film is formed to recover the damage caused by the dry etching generated on the inner wall of the groove and to relieve the stress generated at the interface between the silicon oxide film 104 embedded in the groove and the substrate 1 in the next step. I do.

  Next, as shown in FIG. 25, a silicon oxide film 104 is deposited on the substrate 1 including the inside of the groove by a CVD method, and the silicon oxide film 104 on the top of the groove is chemically The surface is planarized by mechanical and mechanical polishing. Next, by removing the silicon nitride film 3, a silicon oxide film 104a for improving the breakdown voltage of the element isolation 104 and the high-breakdown-voltage MISFETs Qn2 and Qp2 is completed (FIG. 26A).

  Here, as shown in FIG. 26B, the surfaces of the silicon oxide films 104 and 104a are thin before the above-described polishing, cleaning of the surface of the semiconductor substrate in a subsequent impurity implantation step or the like, or before formation of the silicon oxide film 5a. Due to the removal of the silicon oxide film 2 or the like, a phenomenon (recess phenomenon) occurs in which the surfaces of the silicon oxide films 104 and 104a recede at the ends of the grooves. As will be described later in detail when the recess phenomenon occurs, various problems such as deterioration of the breakdown voltage of the MISFET and occurrence of a kink phenomenon may occur. In the following drawings, the receding surfaces of the silicon oxide films 104 and 104a are not shown for the sake of simplicity.

  In the following steps, steps similar to those in the first embodiment will be described only briefly, avoiding redundant description.

  First, as shown in FIG. 27, boron is ion-implanted under the silicon oxide films 104 and 104a in the high breakdown voltage n-channel MISFET formation region HN to form a p-type well 6.

  Further, phosphorus is ion-implanted under the silicon oxide films 104 and 104a in the high breakdown voltage p-channel MISFET formation region HP to form the n-type well 7.

  The implantation energy of the ions (phosphorus, boron) at this time is set so that the ions are also implanted under the silicon oxide films 104 and 104a in the high-breakdown-voltage n-channel MISFET formation region HN and the high-breakdown-voltage p-channel MISFET formation region HP. I do.

  Next, as shown in FIG. 28, boron is ion-implanted in the vicinity of the source and drain regions of the high-breakdown-voltage p-channel MISFET Qp2 to form the p-type electric field relaxation layer 8. Further, an n-type electric field relaxation layer 9 is formed by ion-implanting phosphorus near the source and drain regions of the high-breakdown-voltage n-channel MISFET Qn2. The ion (phosphorus, boron) implantation energy at this time is set so that the ions are also implanted under the silicon oxide films 104 and 104a.

  Next, as shown in FIG. 29, after removing the thin silicon oxide film 2 on the surface of the semiconductor substrate 1, a silicon oxide film 5a to be a part of the gate insulating film 5 is formed by thermal oxidation. Next, a silicon oxide film 5b is deposited on the semiconductor substrate 1 by a low pressure chemical vapor deposition method. Next, the silicon oxide film 5b is left over the silicon oxide film 104 in the regions where the gate electrodes of the high-breakdown-voltage MISFETs Qn2 and Qp2 are to be formed and the high-breakdown-voltage n-channel MISFET formation region HN and the high-breakdown-voltage p-channel MISFET formation region HP. The silicon oxide film 5b is patterned. Here, the silicon oxide film 104 (the boundary between the high-breakdown-voltage portion and the low-breakdown-voltage portion; in the drawing, the high-breakdown-voltage n-channel MISFET formation region LN and the low-breakdown-voltage p-channel MISFET formation region LP are formed) The silicon oxide film 5b is not left over the field oxide film 4 on the boundary between the region HN and the low breakdown voltage p-channel MISFET formation region LP). As described in the first embodiment, since the width of the silicon oxide film 104 on these regions is narrow, the width of the source and drain regions or the gate electrodes of the MISFETs Qn1 and Qn2 due to mask misalignment is prevented from being reduced. That's why.

  Next, by performing a heat treatment at 900 ° C. or higher, the film quality of the silicon oxide film 5b is improved. The silicon oxide film after the heat treatment is set to 5c. The silicon oxide film 5 c on the region where the gate electrode of the high breakdown voltage MISFETs Qn 2 and Qp 2 is to be formed becomes a part of the gate insulating film 5. That is, the silicon oxide film 5c and the silicon oxide film 5a form the gate insulating film 5 of the high-breakdown-voltage MISFETs Qn2 and Qp2.

  Further, the threshold voltage Vt of the parasitic MOS formed on these regions is increased by the silicon oxide film 5c on the silicon oxide film 104 in the high-breakdown-voltage n-channel MISFET formation region HN and the high-breakdown-voltage p-channel MISFET formation region HP. can do.

  Further, since the silicon oxide film 5b is formed by LPCVD, the etching ratio with respect to the silicon oxide films 104 and 104a can be increased, so that the surface of the silicon oxide films 104 and 104a is hardly etched. Can be etched. As a result, the thickness of the silicon oxide film 104 can be secured, and the threshold potential Vt of the parasitic MOS formed thereon can be increased. Further, the amount of recession of the surfaces of the silicon oxide films 104 and 104a due to the recess phenomenon described above can be reduced.

  Next, as shown in FIG. 30, a polycrystalline silicon film 10 is deposited on the semiconductor substrate 1 by a CVD method. The polycrystalline silicon film 10 may contain impurities such as phosphorus. Next, the polycrystalline silicon film 10 is patterned so as to remain on the gate insulating films 5 (5a, 5c) of the high breakdown voltage MISFETs Qn2, Qp2. This polycrystalline silicon film 10 becomes the gate electrode FG of the high-breakdown-voltage MISFETs Qn2 and Qp2.

  Next, as shown in FIG. 31, boron is ion-implanted into the low-breakdown-voltage n-channel MISFET formation region LN to form a p-type well 8b. At the time of this ion implantation, the p-type well 8c may also be formed by ion-implanting boron below the silicon oxide film 104 in the high-breakdown-voltage n-channel MISFET formation region HN. Further, the n-type well 9b is formed by ion-implanting phosphorus into the low breakdown voltage p-channel MISFET formation region LP. At the time of this ion implantation, the n-type well 9c may be formed also by implanting boron below the silicon oxide film 104 in the high breakdown voltage p-channel MISFET formation region HP. The p-type well 8c and the n-type well 9c are formed to increase the threshold potential Vt of the parasitic MOS formed on the silicon oxide film 104.

  Next, as shown in FIG. 32, after removing the thin silicon oxide film 5a on the low-breakdown-voltage n-channel MISFET formation region LN and the low-breakdown-voltage p-channel MISFET formation region LP, the gate insulating films of the low-breakdown-voltage MISFETs Qn1 and Qp1 are removed. 5d is formed by thermal oxidation.

  Next, a polycrystalline silicon film 11 is deposited on the semiconductor substrate 1 by a CVD method. Next, the polycrystalline silicon film 11 is patterned so as to remain on the gate insulating film 5d of the low-breakdown-voltage MISFETs Qn1 and Qp1. This polycrystalline silicon film 11 becomes the gate electrode SG of the low-breakdown-voltage MISFETs Qn1 and Qp1. After forming a tungsten silicide layer on the surface of the polycrystalline silicon film 11, the gate electrode SG may be formed by patterning. This silicide layer is formed to reduce the resistance of the gate electrode SG.

Next, as shown in FIG. 33A, an n ⁻ -type semiconductor region 13 is formed by ion-implanting phosphorus on both sides of the gate electrode SG of the low-breakdown-voltage MISFET Qn1. In addition, boron is ion-implanted on both sides of the gate electrode SG of the low-breakdown-voltage MISFET Qn2 to form the p ⁻ type semiconductor region 14.

  Next, after a silicon oxide film 15 is formed on the gate electrodes FG and SG, a silicon oxide film is deposited on the semiconductor substrate 1 and etched back to form a laminated film of the gate electrodes FG, SG and the silicon oxide film 15. A sidewall film 16s is formed on the side wall of.

Next, arsenic is ion-implanted on both sides of the gate electrodes (SG, FG) of the low-breakdown-voltage n-channel MISFET Qn1 and the high-breakdown-voltage n-channel MISFET Qn2, thereby forming the n ⁺ -type semiconductor region 17. Further, by implanting boron ions, p ⁺ -type semiconductor regions 18 are formed on both sides of the gate electrodes (SG, FG) of the low-breakdown-voltage p-channel MISFET Qp1 and the high-breakdown-voltage p-channel MISFET Qp2. At this time, arsenic and boron are not implanted below the silicon oxide films 104 and 104a and the silicon oxide film 5c.

In the steps up to this point, the source and the drain (the n ⁻ type semiconductor region 13 and the n ⁺ type semiconductor region 17, the p ⁻ type semiconductor regions 14 and the p ⁻ type semiconductor regions) having the LDD (Lightly Doped Drain) structure are formed in the low breakdown voltage portions (LN, LP). ^The low-breakdown-voltage MISFETs Qn1 and Qp1 including the ⁺ type semiconductor region 18) are formed. Further, high-breakdown-voltage MISFETs Qn2 and Qp2 are formed in the high-breakdown-voltage portions (HN, HP).

  As described above, according to the present embodiment, the thickness of the silicon oxide film 104 can be ensured, so that the occurrence of a recess can be reduced. As a result, it is possible to reduce the decrease in the withstand voltage and the occurrence of the kink phenomenon due to the recess. Here, the decrease in the breakdown voltage is caused by the concentration of the electric field at the step on the surface of the silicon oxide film 104 generated by the recess. Also. The kink phenomenon is a phenomenon in which the sub-threshold characteristic of the MISFET (the characteristic based on the relationship between the gate voltage (horizontal axis) and the drain current (vertical axis)) has a large drain current in a region where the gate voltage is small, and shows a two-stage waveform. Say.

  FIG. 33 (b) is an enlarged view of FIG. 33 (a), and also illustrates the recess described with reference to FIG. 26 (b).

  Next, a multilayer wiring is formed by repeatedly forming an interlayer insulating film and a metal for wiring on these MISFETs Qn1, Qn2, Qp1, and Qp2, and a protective film covering the entire chip is formed on the uppermost wiring. Although it is formed, its figure and detailed description are omitted.

(Embodiment 3)
The method of manufacturing the semiconductor integrated circuit device according to the present embodiment will be described in the order of steps with reference to FIGS.

  First, as shown in FIG. 34, the semiconductor substrate 1 in which the gate electrode FG is formed on the gate insulating film 5 (5a, 5c) of the high-breakdown-voltage MISFETs Qn2, Qp2 is prepared. The manufacturing process of the semiconductor substrate 1 is the same as that of the first embodiment described with reference to FIGS. Note that the semiconductor substrate illustrated in FIG. 34 has the silicon oxide film 5c over the silicon oxide films 104 and 104a; therefore, as in Embodiment 1, the thickness of the silicon oxide film 104 is ensured. Therefore, the threshold potential Vt of the parasitic MOS formed thereon can be increased.

  Next, as shown in FIG. 35, after removing the thin silicon oxide film 5a on the low-breakdown-voltage n-channel MISFET formation region LN and the low-breakdown-voltage p-channel MISFET formation region LP, the gate insulating films of the low-breakdown-voltage MISFETs Qn1 and Qp1 are removed. 5d is formed by thermal oxidation. At this time, the gate electrodes FG of the high breakdown voltage MISFETs Qn2 and Qp2 are also slightly oxidized (5e). Also, the surface of the lower electrode LE is slightly oxidized to form a silicon oxide film (5f) (FIG. 35). This silicon oxide film 5f becomes a capacitive insulating film of the capacitive element C. In order to enhance the reliability of the capacitive element C, a silicon nitride film may be formed on the polycrystalline silicon film 10 in advance after the polycrystalline silicon film 10 serving as the lower electrode LE is deposited, and may be used as a capacitive insulating film.

  Next, heat treatment is performed in a nitrogen atmosphere to nitride the gate insulating film 5d. As described above, by introducing nitrogen to the interface of the gate insulating film 5d, the fluctuation of the threshold potential Vt due to hot carriers generated at the drain end can be suppressed.

  Next, as shown in FIG. 36, a polycrystalline silicon film 111 is deposited on the semiconductor substrate 1 by a CVD method. This polycrystalline silicon film 111 becomes a part of the gate electrode SG of the low-breakdown-voltage MISFETs Qn1 and Qp1.

  Here, if this nitriding treatment is performed after an impurity implantation step for adjusting a threshold potential Vt described later, impurities are diffused by the nitriding treatment, and it becomes difficult to adjust the threshold potential Vt. On the other hand, even when the impurity implantation step is performed after the nitriding treatment, when the polycrystalline silicon film 111 is formed after the impurity implantation step, the impurity is implanted with the gate insulating film 5d exposed. This causes a problem that the gate insulating film 5d is contaminated by heavy metals existing in the ion implantation apparatus.

  Therefore, as described below, with the polycrystalline silicon film 111 formed on the gate insulating film 5d, impurities are ion-implanted into the semiconductor substrate 1 via the polycrystalline silicon film 111.

  First, as shown in FIG. 36, impurities are ion-implanted on the semiconductor substrate 1 in order to adjust the threshold potential Vt of the low-breakdown-voltage MISFET Qn1. Next, as shown in FIG. 37, an impurity is ion-implanted on the low breakdown voltage p-channel MISFET formation region LP. This impurity is used to adjust the threshold potential Vt of the low breakdown voltage MISFET Qp1. At this time, since the silicon oxide film 5e and the polycrystalline silicon film 111 are formed on the gate electrodes FG of the high-breakdown-voltage MISFETs Qn2 and Qp2, the impurities remain in these films and the gate insulating film 5 (5a , 5c) can be prevented from being implanted.

  When impurities are implanted into the gate insulating film 5, the problem of so-called NBT (negative bias temperature) becomes significant. This refers to a phenomenon in which the threshold potential Vt is increased only by applying a negative potential to the gate electrode of a p-channel MISFET, and this phenomenon is particularly remarkable when the gate electrode is a p-type. It is considered that this phenomenon is deeply related to the presence of boron in the gate insulating film, and is likely to occur when the gate insulating film contains impurities.

  However, in the present embodiment, it is possible to prevent impurities from being implanted into gate insulating film 5 and to reduce the occurrence of the NBT phenomenon.

  Next, a polycrystalline silicon film 111b is deposited on the polycrystalline silicon film 111. The polycrystalline silicon films 111 and 111b serve as gate electrodes SG of the low-breakdown-voltage MISFETs Qn1 and Qp1. Therefore, the polycrystalline silicon films 111 and 111b are patterned so as to remain on the gate insulating film 5d (FIG. 38). At this time, the polycrystalline silicon films 111 and 111b are also left on the silicon oxide film 5f on the lower electrode LE in the capacitive element formation region CA. The polycrystalline silicon films 111 and 111b serve as upper electrodes UE of the capacitive element C. Note that the gate electrode SG may be formed by patterning after forming a tungsten silicide layer on the surface of the polycrystalline silicon film 111b. This tungsten silicide layer is formed by depositing a metal film such as a tungsten film on the polycrystalline silicon film 111b and performing a heat treatment. This silicide layer is formed to reduce the resistance of the gate electrode SG.

  In the above-described patterning of the polycrystalline silicon film 10, only the polycrystalline silicon film 10 on the low withstand voltage portion (LN, LP) is removed, and the polycrystalline silicon film 10 on the high withstand voltage portion (HN, HP) is removed. The patterning may be performed after the formation of the gate electrode SG.

  As described above, the gate electrode SG of the low-breakdown-voltage MISFETs Qn1 and Qp1 is a stacked film of the polycrystalline silicon film 111 and the polycrystalline silicon film 111b because the impurities for adjusting the threshold potential of the low-breakdown-voltage MISFETs Qn1 and Qp1 are precisely formed. This is for ion implantation. That is, in the case where ion implantation is performed through the polycrystalline silicon film 111 having a large thickness before the ion implantation, it is difficult to control impurities, and a desired threshold potential Vt cannot be obtained.

  Further, as described above, when the silicide layer is formed on the gate electrode SG, if the polycrystalline silicon film 111 constituting the gate electrode is thin, even the silicon in the gate insulating film under the silicide causes a silicidation reaction. As a result, the breakdown voltage of the gate insulating film 5d decreases.

  However, in the present embodiment, the gate electrode SG of the low-breakdown-voltage MISFETs Qn1 and Qp1 is a stacked film of the polycrystalline silicon film 111 and the polycrystalline silicon film 111b. In addition, the withstand voltage of the gate insulating film 5d can be ensured.

  Next, the source and drain regions of the low-breakdown-voltage MISFETs Qn1 and Qp1 and the high-breakdown-voltage MISFETs Qn2 and Qp2 are formed. The subsequent steps are the same as those in the first embodiment described with reference to FIGS. , The description of which will be omitted.

  In the present embodiment, as shown in FIG. 34, the gate electrode formation scheduled regions of high breakdown voltage MISFETs Qn2 and Qp2, the high breakdown voltage n-channel MISFET formation region HN, the high breakdown voltage p-channel MISFET formation region HP, and the capacitive element Although the semiconductor substrate 1 in which the silicon oxide film 5c is formed on the field oxide film 4 in the formation region CA is used, even if the step of forming the silicon oxide film 5c is omitted, boron is left in the gate oxide film 5a. Since the injection can be prevented, the occurrence of the NBT phenomenon can be suppressed.

  FIG. 39 is a cross-sectional view of a main part of the semiconductor substrate in a case where the silicon oxide film 5c is not formed. The method of manufacturing the semiconductor integrated circuit device is the same as that of the first embodiment (excluding the step of forming the silicon oxide film 5c) and the steps described in the present embodiment, and a description thereof will be omitted.

  As described above, the invention made by the inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the gist of the invention. Needless to say.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a semiconductor integrated circuit device and its manufacturing technology, and is particularly suitable for a semiconductor integrated circuit device in which a high-breakdown-voltage MISFET and a low-breakdown-voltage MISFET are formed on the same semiconductor substrate and a manufacturing technology thereof.

FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view of a principal part of the substrate, illustrating the method for manufacturing the semiconductor integrated circuit device according to the first embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a main part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a second embodiment of the present invention. FIG. 14 is a cross-sectional view of a principal part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view of a principal part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view of a principal part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view of a principal part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view of a principal part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view of a principal part of a substrate, illustrating a method of manufacturing a semiconductor integrated circuit device according to a third embodiment of the present invention. It is a figure for explaining a subject of the present invention. It is a figure for explaining a subject of the present invention. It is a figure for explaining a subject of the present invention.

Explanation of reference numerals

Reference Signs List 1 semiconductor substrate 2 silicon oxide film 3 silicon nitride film 4 field oxide film 4a field oxide film 5 gate insulating film 5a silicon oxide film 5b silicon oxide film 5c silicon oxide film 5d gate insulating film 5f silicon oxide film 6 n-type isolation region ( n-type well)
Reference Signs List 7 p-type well 8 p-type electric field relaxation layer 8b p-type well 8c p-type well 8d semiconductor region 9 n-type electric field relaxation layer 9b n-type well 9c n-type well 9d semiconductor region 10 polycrystalline silicon film 11 polycrystalline silicon film 13 n ^- -type semiconductor region 14 p ^- -type semiconductor regions 16s sidewall film 17 n ⁺ -type semiconductor region (source, drain regions)
18 p ⁺ type semiconductor region (source, drain region)
104 silicon oxide film 104a silicon oxide film 111 polycrystalline silicon film 111b polycrystalline silicon film FG gate electrode SG gate electrode SZ interlayer insulating film U groove C capacitive element UE upper electrode LE lower electrode R1 to R10 resist film M1 first layer wiring CA Capacitance element formation region HN High breakdown voltage n-channel MISFET formation region HP High breakdown voltage p-channel MISFET formation region LN Low breakdown voltage n-channel MISFET formation region LP Low breakdown voltage p-channel MISFET formation region Qn1 Low breakdown voltage n-channel MISFET
Qn2 High withstand voltage n-channel MISFET
Qp1 Low breakdown voltage p-channel MISFET
Qp2 High breakdown voltage p-channel MISFET

Claims (29)

A semiconductor integrated circuit device having a first region and a second region on a semiconductor substrate,
(A) a plurality of first insulating films formed on the semiconductor substrate;
(B) a second insulating film formed on the surface of the semiconductor substrate between the first insulating films in the second region;
(C) a third insulating film formed on the first insulating film in the first region, wherein the third insulating film is formed on the first insulating film and the second insulating film in the second region. Three insulating films,
(D) a plurality of first conductive films formed on the third insulating film;
A semiconductor integrated circuit device comprising:   2. The threshold voltage of a parasitic MOS formed between the first conductive film and the semiconductor substrate is increased by the third insulating film formed on the first insulating film. Semiconductor integrated circuit device. The second and third insulating films in the second region constitute a gate insulating film of a first MISFET formed in the second region;
3. The semiconductor integrated circuit device according to claim 1, wherein the first conductive film in the second region forms a gate electrode of the first MISFET. The semiconductor integrated circuit device further comprises:
(E) a fourth insulating film formed on the first conductive film in the first region;
(F) a second conductive film formed on the fourth insulating film;
Has,
The first conductive film forms a lower electrode of a capacitor formed in the first region;
4. The semiconductor integrated circuit device according to claim 1, wherein said second conductive film forms an upper electrode of said capacitor. The semiconductor integrated circuit device further includes a second MISFET in a third region of the semiconductor substrate,
The fourth insulating film is formed on the semiconductor substrate in the third region,
The second conductive film is formed on the fourth insulating film in the third region,
The fourth insulating film in the third region forms a gate insulating film of the second MISFET;
5. The semiconductor integrated circuit device according to claim 4, wherein said second conductive film in said third region forms a gate electrode of said second MISFET.   6. The semiconductor integrated circuit device according to claim 4, wherein the sum of the thickness of the second insulating film and the thickness of the third insulating film is larger than the thickness of the fourth insulating film.   7. The semiconductor integrated circuit device according to claim 4, wherein nitrogen is introduced into said fourth insulating film.   8. The semiconductor integrated circuit device according to claim 1, wherein said third insulating film is a film formed by a CVD method.   9. The method according to claim 1, wherein the first insulating film is a film formed by a thermal oxidation method, and has a thickness larger than a thickness of the second insulating film. 3. The semiconductor integrated circuit device according to claim 1.   10. The semiconductor integrated circuit device according to claim 1, wherein the first insulating film is formed so as to be embedded in a groove formed in the semiconductor substrate.   The semiconductor integrated circuit device according to claim 1, wherein a thickness of the third insulating film is larger than a thickness of the second insulating film.   The semiconductor integrated circuit device according to claim 1, wherein the first insulating film is a silicon oxide film.   13. The semiconductor integrated circuit device according to claim 1, wherein said second insulating film is a silicon oxide film.   14. The semiconductor integrated circuit device according to claim 1, wherein the third insulating film is a silicon oxide film.   The semiconductor integrated circuit device according to claim 1, wherein the first MISFET forms a circuit for driving a liquid crystal display device. A method of manufacturing a semiconductor integrated circuit device having first and second regions on a semiconductor substrate, comprising:
(A) forming a plurality of first insulating films on a semiconductor substrate;
(B) forming a second insulating film on the semiconductor substrate between the first insulating films in the second region;
(C) depositing a third insulating film on the semiconductor substrate including the first and second insulating films;
(D) patterning the third insulating film so as to remain on the first insulating film in the first region, on the first insulating film in the second region, and on the second insulating film in the second region. Process,
(E) forming a first conductive film on the third insulating film;
A method for manufacturing a semiconductor integrated circuit device, comprising: The second and third insulating films in the second region constitute a gate insulating film of a first MISFET;
17. The method according to claim 16, wherein the first conductive film in the second region forms a gate electrode of the first MISFET. The method for manufacturing the semiconductor integrated circuit device further includes:
(F) forming a fourth insulating film on the first conductive film in the first region;
(G) forming a second conductive film on the fourth insulating film;
Has,
The first conductive film in the first region forms a lower electrode of a capacitor;
18. The method according to claim 16, wherein the second conductive film in the first region forms an upper electrode of the capacitor. The method for manufacturing a semiconductor integrated circuit device further includes a second MISFET in a third region of the semiconductor substrate,
In the step (f), the fourth insulating film is formed on the semiconductor substrate in the third region,
In the step (g), the second conductive film is formed on the fourth insulating film in the third region,
The fourth insulating film in the third region forms a gate insulating film of a second MISFET;
20. The method according to claim 18, wherein the second conductive film in the third region forms a gate electrode of the second MISFET.   20. The method according to claim 19, wherein the fourth insulating film is formed by a thermal oxidation method.   21. The method according to claim 20, wherein the second conductive film is made of a polycrystalline silicon film.   22. The method according to claim 19, wherein the sum of the thickness of the second insulating film and the thickness of the third insulating film is larger than the thickness of the fourth insulating film. A method for manufacturing a semiconductor integrated circuit device.   23. The method for manufacturing a semiconductor integrated circuit device according to claim 19, wherein nitrogen is introduced into said fourth insulating film.   24. The method of manufacturing a semiconductor integrated circuit device according to claim 16, wherein said third insulating film is formed by a CVD method.   25. The method according to claim 16, wherein the second insulating film is formed by a thermal oxidation method. In the step (a), the first insulating film is formed by a thermal oxidation method,
26. The method of manufacturing a semiconductor integrated circuit device according to claim 16, wherein the thickness of the first insulating film is formed to be larger than the thickness of the second insulating film. . The step (a) comprises:
(A1) forming a groove in the semiconductor substrate;
(A2) burying the first insulating film in the trench;
The method of manufacturing a semiconductor integrated circuit device according to any one of claims 16 to 26, comprising:   28. The method according to claim 16, wherein the thickness of the third insulating film is larger than the thickness of the second insulating film. The method according to any one of claims 16 to 28, wherein the first MISFET forms a circuit for driving a liquid crystal display device.

Images