JP3913201B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a semiconductor device having a capacitor using a ferroelectric film or a high dielectric film as a capacitive insulating film, and a method for manufacturing the same.

  A semiconductor device having a capacitor having a ferroelectric film or a high dielectric film as a capacitive insulating film has a residual polarization due to hysteresis characteristics and a high relative dielectric constant. Therefore, in the fields of nonvolatile memory and DRAM, silicon oxide is used. There is a possibility of replacing a semiconductor device having a capacitive insulating film made of a film or a silicon nitride film. However, the problem is that the memory cell area is large compared to existing memories.

  Various capacitor structures have been proposed to reduce the memory cell area while ensuring the required capacitor charge (capacitor area). As a general rule, an oxygen barrier film is formed on a tungsten or polysilicon plug. There is a method of forming a three-dimensional capacitor through the structure (for example, see Patent Document 1).

  The oxygen barrier film is necessary in order not to oxidize the plug, and what kind of film and film thickness are required depend on the crystallization temperature of the ferroelectric film or the high dielectric film. In general, when the film thickness is increased, the oxygen barrier property is improved, but noble metals such as iridium and iridium oxide which are difficult to be etched are often used, and a thinner film is advantageous for miniaturization.

As a three-dimensional shape, a columnar electrode or an electrode using a concave pattern formed on an insulating film is generally used, but noble metal such as Pt that can be used in a high-temperature oxygen atmosphere is used as an electrode, so that electrode processing is easy. By the way, the latter is dominant.
US Pat. No. 6,239,461 (column 5 line 44- column 6 line 26 fig 5) JP-A-5-251658

  However, when a concave pattern is used, the capacitor area increases as the size of the concave portion increases. However, a pattern that can be stably formed by normal lithography has a hole-to-hole space of about one to one. If the concave portion is enlarged without increasing the cell area, there is a problem that the adjacent pattern comes into contact.

  In addition, a recess that reaches the oxygen barrier film is formed by etching. If the recess is larger than the oxygen barrier film, the side surface of the oxygen barrier film is also exposed during etching, and the substantial oxygen barrier film thickness is reduced. There is a problem.

  As a method for forming a ferroelectric film or a high dielectric film, the MOCVD method is generally used. However, since a plurality of organometallic sources are used, it is important to match the composition and film thickness at all electrode positions. It is a problem. Further, when the composition is shifted or the film thickness is reduced, a leak failure is caused. When the film thickness is increased, a retention failure due to insufficient writing is caused. Therefore, a complicated structure in which an electrode having an uneven surface and an MOCVD source used in a DRAM to increase the capacitor area is difficult to enter (see, for example, JP-A-5-251658, page 3, and FIG. 1). Cannot be used.

  As described above, in the conventional semiconductor device, it is difficult to reduce the memory cell area while securing a necessary capacitor area.

  The present invention solves the above-described problem, and by securing the capacitor area by increasing the size of the concave portion of the capacitor without contacting with the adjacent pattern, the over-etching around the oxygen barrier film is suppressed. Accordingly, it is an object to suppress the oxygen barrier film thickness and facilitate miniaturization.

In order to achieve the above object, a first semiconductor device according to the present invention includes a conductive oxygen barrier film formed on a substrate, a side surface and an upper side of the oxygen barrier film, and an upper surface of the oxygen barrier film. A first insulating film having an opening exposing the bottom, a lower electrode formed along a bottom surface and a side surface of the opening, a second insulating film formed between the side surface of the opening and the lower electrode, A capacitor insulating film formed on the first and second insulating films and along the surface of the lower electrode, and an upper electrode formed along the surface of the capacitor insulating film, and the opening is formed on the bottom surface of the opening. At least a portion is formed so as to protrude from the upper surface of the oxygen barrier film, and the bottom surface of the protruding portion is located below the upper surface of the oxygen barrier film, so that the groove is formed from a portion protruding around the upper surface of the oxygen barrier film. And the trench region is a second insulating film It is embedded.

According to the first semiconductor device, the capacitor area can be increased by making the opening of the first insulating film larger than the oxygen barrier film. In addition, over-etching around the oxygen barrier film at the time of forming the opening can be suppressed to the distance between the side surface of the oxygen barrier film and the side surface of the opening. Further, by forming the second insulating film, it is possible to suppress erosion during CMP (decrease in the height of the insulating film and variations in the capacitor array position) that becomes conspicuous as the distance between adjacent openings decreases.

  Further, by using a silicon oxide film as the first insulating film and a silicon nitride film as the second insulating film and a general material used in semiconductor manufacturing, manufacturing can be facilitated.

  In addition, when the capacitor insulating film is a ferroelectric film or a high dielectric film, the oxygen barrier film thickness is large, so that the effect of suppressing the overetching around the oxygen barrier film is remarkable.

  A first method for manufacturing a semiconductor device according to the present invention includes a step of forming an insulating film so as to cover an oxygen barrier film formed on a substrate, and an upper surface region of the oxygen barrier film in the insulating film using a mask. In the step of forming the opening reaching the oxygen barrier film and isotropic etching, the opening is expanded to the outside of the upper surface region of the oxygen barrier film, so that the opening protrudes from the oxygen barrier film. A step of forming a groove region, a step of forming a lower electrode along the bottom and side surfaces of the opening including the groove region, a step of forming a capacitive insulating film on the insulating film and on the surface of the lower electrode, and a capacitance Forming an upper electrode along the surface of the insulating film.

  According to the first method for manufacturing a semiconductor device, since the opening of the lower electrode pattern is expanded to the outside of the oxygen barrier film by isotropic etching, contact with an adjacent opening can be prevented. Further, the over-etching around the oxygen barrier film can be suppressed to the extent of the distance between the side surface of the oxygen barrier film and the side surface of the opening.

  A second method for manufacturing a semiconductor device according to the present invention includes a step of forming an insulating film so as to cover an oxygen barrier film formed on a substrate, and an upper surface region of the oxygen barrier film in the insulating film using a mask. Forming an opening that does not reach the oxygen barrier film, and expanding the opening to the outside of the upper surface region of the oxygen barrier film by isotropic etching, and allowing the opening to reach the oxygen barrier film; Forming a lower electrode along the bottom and side surfaces of the opening, forming a capacitive insulating film on the insulating film and on the surface of the lower electrode, and forming an upper electrode along the surface of the capacitive insulating film Process.

  According to the second method for manufacturing a semiconductor device, since the opening of the lower electrode pattern is expanded to the outside of the oxygen barrier film by isotropic etching, contact with an adjacent opening can be prevented. At the same time, since the opening reaches the oxygen barrier film, over-etching around the oxygen barrier film can be suppressed.

  In the first and second semiconductor device manufacturing methods, after an electrode film is formed on the insulating film and along the bottom and side surfaces of the opening, only the electrode film on the insulating film is formed by CMP or resist etch back. By forming the lower electrode by removing, adjacent capacitors can be easily separated.

  The third method for manufacturing a semiconductor device according to the present invention includes a step of forming a first insulating film so as to cover an oxygen barrier film formed on a substrate, and an oxygen in the first insulating film using a mask. The step of forming an opening reaching the oxygen barrier film in the upper surface region of the barrier film and the isotropic etching to expand the opening to the outside of the upper surface region of the oxygen barrier film, thereby providing an oxygen barrier in the opening. Forming a groove region in a portion protruding from the film; forming a second insulating film on the first insulating film along a bottom surface and a side surface of the opening including the groove region; and a side surface of the opening And leaving only the second insulating film formed in the trench region and removing the other portion of the second insulating film, the first insulating film, the bottom surface of the opening, and the second insulating film A step of forming an electrode film along the surface, and other than the inside of the opening by CMP Forming a lower electrode comprising an electrode film in the opening by removing the polar film; forming a capacitive insulating film on the first and second insulating films and on the surface of the lower electrode; and capacitive insulation Forming an upper electrode along the film surface.

  According to the third method for manufacturing a semiconductor device, since the opening of the lower electrode pattern is expanded to the outside of the oxygen barrier film by isotropic etching, contact with an adjacent opening can be prevented. Further, the over-etching around the oxygen barrier film can be suppressed to the extent of the distance between the side surface of the oxygen barrier film and the side surface of the opening. Further, by forming a second insulating film on the side surface and groove region of the opening, erosion during CMP that becomes more prominent as the distance between adjacent openings becomes smaller (decreasing the height of the insulating film and the position of the capacitor array). Variation).

  Further, the first insulating film can be easily manufactured by using a silicon oxide film and the second insulating film of the CMP stopper film using a silicon nitride film and a general material used in semiconductor manufacturing.

  A fourth method for manufacturing a semiconductor device according to the present invention includes a step of forming a first insulating film so as to cover an oxygen barrier film formed on a substrate, and a second insulating film on the first insulating film. And isotropically etching the second insulating film using a mask to form an opening in the second insulating film that includes the upper surface region of the oxygen barrier film and that is wider than the upper surface region. Forming, etching the first insulating film using the second insulating film as a mask to reach the opening to the oxygen barrier film, and forming a lower electrode along the bottom and side surfaces of the opening And forming a capacitive insulating film along the second insulating film and the lower electrode surface, and forming an upper electrode along the capacitive insulating film surface.

  According to the fourth method of manufacturing a semiconductor device, since the hard mask using the second insulating film is used instead of the resist mask, the oxygen barrier film is reached while preventing contact with the adjacent opening. An opening wider than the oxygen barrier film can be formed.

  Further, by using a silicon oxide film as the first insulating film and a silicon nitride film as the second insulating film and a general material used in semiconductor manufacturing, manufacturing can be facilitated.

A fifth method for manufacturing a semiconductor device according to the present invention includes a step of forming a first insulating film on a substrate and an oxygen barrier film formed on the substrate so as to protrude from the periphery , and CMP or resist etch back. A step of planarizing the first insulating film so that an upper surface of the oxygen barrier film is exposed by a method ; a step of forming a second insulating film on the oxygen barrier film and the first insulating film; Forming an opening reaching the oxygen barrier film in the insulating film over a region including the upper surface region of the oxygen barrier film and wider than the upper surface region ; and forming a lower electrode along the bottom and side surfaces of the opening. And a step of forming a capacitive insulating film along the surface of the second insulating film and the lower electrode, and a step of forming an upper electrode along the surface of the capacitive insulating film.

  According to the fifth method for manufacturing a semiconductor device, the first insulating film is formed around the oxygen barrier film, whereby the oxygen barrier film when the opening reaching the oxygen barrier film is formed in the second insulating film. Overetching of the peripheral portion can be suppressed, thereby suppressing (thinning) the oxygen barrier film thickness.

  Further, by using a silicon nitride film as the first insulating film and a silicon oxide film as the second insulating film and a general material used in semiconductor manufacturing, manufacturing can be facilitated.

  In addition, when the capacitor insulating film is a ferroelectric film or a high dielectric film, the oxygen barrier film thickness is large, so that the effect of suppressing the overetching around the oxygen barrier film is remarkable.

  According to the present invention, in a capacitor using a ferroelectric film or a high dielectric film as a capacitor insulating film, the capacitor area is secured by increasing the size of the concave portion (opening) of the capacitor without contacting the adjacent pattern. However, the area of the memory cell can be reduced, and the over-etching around the oxygen barrier film can be suppressed, so that the oxygen barrier film thickness can be suppressed and the miniaturization can be facilitated.

(First embodiment)
The semiconductor device according to the first embodiment of the present invention will be described below with reference to FIG.

  An element isolation layer 102, a polycrystalline silicon wiring 103, a diffusion layer 104, and a silicide layer 105 are formed on the semiconductor substrate 101. On top of that, a tungsten wiring 107 and an interlayer film 108 with a planarized surface are formed with an interlayer film 106 with a planarized surface interposed therebetween. A plug 109 having a diameter of 200 nm made of tungsten using titanium and titanium nitride as a barrier metal is formed in a contact hole that penetrates the interlayer film 106 and the interlayer film 108 and reaches the silicide layer 105.

  An oxygen barrier film 110 is formed from the lower layer so as to cover the upper surface of the plug 109. The oxygen barrier film 110 is formed of a titanium aluminum nitride 100 nm, iridium 50 nm, iridium oxide 200 nm square having a side of 400 nm and a distance of 200 nm from the adjacent pattern. A silicon oxide film 111b having a residual film on the oxygen barrier film 110 having a circular opening with a diameter of 500 nm in a silicon oxide film 111b having a diameter of 500 nm, and a contact hole having a distance of 100 nm from the adjacent pattern is exposed on the upper surface of the oxygen barrier film 110. Is formed. The silicon oxide film 111b in the range of 50 nm from the side surface of the oxygen barrier film 110 (dimension B in FIG. 1) is also etched by 50 nm (dimension A in FIG. 1) downward from the upper surface position of the oxygen barrier film 110.

  A lower electrode 112a made of platinum 30 nm is formed on the inner wall of the contact hole, and a strong bismuth layered perovskite oxide 60 nm containing strontium, bismuth, tantalum, and niobium on the surface of the lower electrode 112a and the silicon oxide film 111b. A dielectric capacitor insulating film 113 and an upper electrode 114 made of 30 nm of platinum are formed.

  A method for manufacturing a semiconductor device according to the first embodiment of the present invention will be described below with reference to FIGS. 2 (a) to 2 (f) and FIGS. 3 (a) to 3 (e).

  First, as shown in FIG. 2A, after forming the element isolation layer 102 and the polycrystalline silicon wiring 103 on the semiconductor substrate 101, the diffusion layer 104 and the silicide layer 105 are formed. Next, after an interlayer film 106 with a planarized surface is formed, a tungsten wiring 107 is formed, and an interlayer film 108 with a planarized surface is further formed.

  Next, as shown in FIG. 2B, a contact hole having a diameter of 200 nm that reaches the silicide layer 105 through the interlayer film 106 and the interlayer film 108 is formed by dry etching, and then 10 nm of titanium and 20 nm of titanium nitride are formed. A 200 nm tungsten film is formed by CVD or sputtering. Next, these metal films are left only in the contact holes by CMP to form plugs 109.

  Next, as shown in FIG. 2 (c), titanium aluminum nitride 100 nm, iridium 50 nm, and iridium oxide 200 nm are stacked by sputtering, and a square with a side of 400 nm so as to cover the upper surface of the plug 109 by dry etching, An oxygen barrier film 110 having a distance of 200 nm is formed.

  Next, as shown in FIG. 2D, a silicon oxide film having a thickness of 1400 nm is formed on the oxygen barrier film 110, and planarized by CMP so that the remaining film on the oxygen barrier film 110 becomes 700 nm. A silicon oxide film 111 is formed.

  Next, as shown in FIG. 2E, a photoresist 115 having a circular opening having a thickness of 700 nm and a diameter of 300 nm above the oxygen barrier film 110 and having a distance of 300 nm from the adjacent pattern is formed. .

  Next, as shown in FIG. 2F, a silicon oxide film 111a having substantially the same shape as the photoresist 115 is formed by dry etching using plasma containing a gas containing C, H, F and a gas containing O. .

  Next, as shown in FIG. 3A, the photoresist 115 is removed using plasma of a gas containing O.

  Next, as shown in FIG. 3B, the silicon oxide film 111a is isotropically etched by 100 nm using vaporous hydrogen fluoride, the remaining film on the oxygen barrier film 110 is 600 nm, and the diameter is 500 nm. A silicon oxide film 111b having a circular opening having a distance of 100 nm from the adjacent pattern is formed. At this time, since the side surface of the opening recedes to form a pattern larger than the oxygen barrier film 110, the silicon oxide film 111b on the side surface of the oxygen barrier film 110 is also etched by 50 nm from above.

  Next, as shown in FIG. 3C, a platinum film 112 is formed to a thickness of 30 nm by sputtering or CVD. Next, as shown in FIG. 3D, only the platinum film 112 on the main surface is removed by CMP or resist etch-back to form the lower electrode 112a. Next, as shown in FIG. 3E, a ferroelectric film made of a bismuth layered perovskite oxide containing strontium, bismuth, tantalum, and niobium as a component is formed by MOCVD, and then 30 nm of platinum is formed by sputtering. A ferroelectric capacitor insulating film 113 and an upper electrode 114 are formed. Thereafter, although not shown in the figure, wiring formation, protective film formation, and the like are performed.

  According to the semiconductor device and the manufacturing method thereof according to the first embodiment, the capacitor area can be increased by making the opening of the insulating film larger than the oxygen barrier film 110.

  In the method of forming a large photoresist, it is easy to come into contact with an adjacent pattern, and the pattern cannot be formed stably. Further, since the pattern becomes larger than the oxygen barrier film, the peripheral portion of the oxygen barrier film is over-etched, and the substantial oxygen barrier film thickness is reduced. When the pattern is formed by dry etching, overetching of 20% to 30% is required due to film thickness variation and etching rate variation. Therefore, when the film thickness is 600 nm, 120 nm to 180 nm is formed around the oxygen barrier film. And a big over-etching will enter.

  As described above, according to the present embodiment, the opening of the lower electrode pattern is expanded to the outside of the oxygen barrier film 110 by isotropic etching, so that contact with the adjacent opening can be prevented and the capacitor area can be reduced. Can be big. In addition, since over-etching around the oxygen barrier film 110 can be suppressed to a distance between the side surface of the oxygen barrier film 110 and the side surface of the opening, the oxygen barrier film 110 can be thinned. Further, by forming the lower electrode 112a by CMP or resist etch back method, adjacent capacitors can be easily separated.

  In addition, since the capacitor insulating film is a ferroelectric film, the film thickness is increased, and the effect of expanding the opening becomes remarkable. Further, since the capacitor insulating film is a ferroelectric film, the oxygen barrier film thickness is increased, and the effect of suppressing over-etching around the oxygen barrier film becomes significant.

(Second Embodiment)
Hereinafter, a method for manufacturing a semiconductor device according to the second embodiment of the present invention will be described with reference to FIGS. A description of the same parts as those in the first embodiment will be omitted.

  First, as shown in FIG. 4A, as in the first embodiment, the silicon oxide film planarized by CMP so that the remaining film on the oxygen barrier film 210 becomes 700 nm on the oxygen barrier film 210. After forming 211, a photoresist 215 having a circular opening with a thickness of 700 nm and a diameter of 300 nm above the oxygen barrier film 210 and a distance of 300 nm from the adjacent pattern is formed. In the second embodiment, the film thickness of iridium oxide in the oxygen barrier film 210 is 100 nm, and the first embodiment in which the film thickness is 200 nm is only that the film thickness of the iridium oxide is 100 nm thin. Different.

  Next, as shown in FIG. 4B, a silicon oxide film 211a having substantially the same shape as the photoresist 215 is formed by dry etching using plasma containing a gas containing C, H, F and a gas containing O. . At this time, the opening of the silicon oxide film 211a does not reach the oxygen barrier film 210 but remains about 100 nm.

Next, as shown in FIG. 4C, after removing the photoresist 115 using a plasma containing a gas containing O, the silicon oxide film 211a isotropically formed using vaporous hydrogen fluoride. Etching is performed to 100 nm to form a silicon oxide film 211b having a remaining film on the oxygen barrier film 210 of 600 nm, a circular opening having a diameter of 500 nm, and a distance of 100 nm from the adjacent pattern. At this time, the side surface of the opening is retracted and the bottom surface is lowered to reach the oxygen barrier film 210, but the silicon oxide film 211b on the side surface of the oxygen barrier film 210 is not etched (in an ideal case, the film thickness is actually (Due to variations and etching rate variations, the silicon oxide film 211b on the side surface of the oxygen barrier film 210 is etched by the variation.)
Next, as shown in FIG. 4D, after a platinum film is formed by sputtering or CVD to a thickness of 30 nm, only the platinum film on the main surface is removed by CMP or resist etch back to form the lower electrode 212a. Next, as shown in FIG. 4E, a ferroelectric film made of a bismuth layered perovskite oxide containing strontium, bismuth, tantalum, and niobium as a component is formed by MOCVD, and then 30 nm of platinum is formed by sputtering. A ferroelectric capacitor insulating film 213 and an upper electrode 214 are formed.

  According to the semiconductor device and the manufacturing method thereof according to the second embodiment, the pattern can be expanded to the outside of the oxygen barrier film 210 while suppressing over-etching around the oxygen barrier film 210. Further, by forming the lower electrode 212a by CMP or resist etch back method, it is possible to easily separate adjacent capacitors.

  As described above, according to the present embodiment, the opening of the lower electrode pattern is expanded to the outside of the oxygen barrier film 210 by isotropic etching, so that contact with the adjacent opening can be prevented and the capacitor area can be reduced. Can be big. At the same time, since the opening reaches the oxygen barrier film 210, overetching around the oxygen barrier film 210 can be suppressed, and the oxygen barrier film 210 can be made thin. Further, by forming the lower electrode 212a by CMP or resist etch back method, it is possible to easily separate adjacent capacitors.

  In addition, since the capacitor insulating film is a ferroelectric film, the film thickness is increased, and the effect of expanding the opening becomes remarkable. Further, since the capacitor insulating film is a ferroelectric film, the oxygen barrier film thickness is increased, and the effect of suppressing over-etching around the oxygen barrier film becomes significant.

(Third embodiment)
A semiconductor device according to the third embodiment of the present invention will be described below with reference to FIG.

  An element isolation layer 102, a polycrystalline silicon wiring 103, a diffusion layer 104, and a silicide layer 105 are formed on the semiconductor substrate 101. On top of that, a tungsten wiring 107 and an interlayer film 108 with a planarized surface are formed with an interlayer film 106 with a planarized surface interposed therebetween. A plug 109 having a diameter of 200 nm made of tungsten using titanium and titanium nitride as a barrier metal is formed in a contact hole that penetrates the interlayer film 106 and the interlayer film 108 and reaches the silicide layer 105.

  An oxygen barrier film 310 is formed from the lower layer so as to cover the upper surface of the plug 109, which is a square of 400 nm on a side made of titanium aluminum nitride 100 nm, iridium 50 nm, and iridium oxide 150 nm and is 200 nm from the adjacent pattern. A silicon oxide film 311b having a remaining film on the oxygen barrier film 310 has a circular opening with a diameter of 500 nm in a silicon oxide film 311b, and a contact hole with a distance of 100 nm from the adjacent pattern is exposed on the upper surface of the oxygen barrier film 310. Is formed. The side surface of the oxygen barrier film 310 is also etched by 50 nm from above.

  A CMP stopper film 312a made of a silicon nitride film 30 nm is formed on the inner wall part of the contact hole, and the side part of the oxygen barrier film 310 etched 50 nm from above is buried. A lower electrode 313a made of platinum 30 nm is formed inside. On the surface of the lower electrode 313a and on the silicon oxide film 311b, there are a ferroelectric capacitor insulating film 314 made of bismuth layered perovskite oxide 60nm composed of strontium, bismuth, tantalum and niobium, and an upper electrode 315 made of platinum 30nm. Is formed.

  Hereinafter, a method for manufacturing a semiconductor device according to the third embodiment of the present invention will be described with reference to FIGS. A description of the same parts as those in the first embodiment will be omitted.

  First, as shown in FIG. 6A, the silicon oxide film is isotropically etched by 100 nm using vaporous hydrogen fluoride in the same manner as in the first embodiment, and the residue on the oxygen barrier film 310 is removed. A silicon oxide film 311b having a circular opening having a thickness of 600 nm, a diameter of 500 nm, and a distance of 100 nm from the adjacent pattern is formed. In the third embodiment, the film thickness of iridium oxide in the oxygen barrier film 310 is 150 nm, and the first embodiment in which the film thickness is 200 nm is only that the film thickness of the iridium oxide is 50 nm thinner. Different. Similar to the first embodiment, the silicon oxide film 311b on the side surface of the oxygen barrier film 310 is also etched by 50 nm from above.

  Next, as shown in FIG. 6B, a silicon nitride film 312 is formed to a thickness of 30 nm by CVD. The side surface portion of the oxygen barrier film 310 etched 50 nm from above is buried.

  Next, as shown in FIG. 6C, only the silicon nitride film 312 on the main surface is removed by CMP or resist etch-back to form a CMP stopper film 312a.

  Next, as shown in FIG. 6D, a platinum film 313 is formed to a thickness of 30 nm by sputtering or CVD. Next, as shown in FIG. 6E, only the platinum film 313 on the main surface is removed by CMP to form a lower electrode 313a. Next, as shown in FIG. 6 (f), a ferroelectric film made of a bismuth layered perovskite oxide containing strontium, bismuth, tantalum, and niobium as a component is formed by MOCVD, and then 30 nm of platinum is formed by sputtering. A ferroelectric capacitor insulating film 314 and an upper electrode 315 are formed.

  As described above, according to the present embodiment, the same effects as those of the first embodiment can be obtained, and the CMP stopper film 312a can become more prominent as the distance between adjacent openings becomes smaller. Erosion (decrease in the height of the insulating film and variation at the capacitor array position) can be suppressed.

  In addition, when CMP is used when forming the CMP stopper film 312a, erosion may occur at that time, but when the erosion during CMP of the silicon nitride film 312 and the platinum film 313 is compared, the silicon oxide film 311b The erosion is smaller in the CMP of the silicon nitride film 312 where it is easy to ensure the selection ratio. Although the area of the opening that determines the area of the capacitor is reduced by the thickness of the CMP stopper film 312a, there is an effect of reducing the variation in the area of the capacitor.

  Further, by using a silicon nitride film, which is a general material used in semiconductors, as the CMP stopper film 312a, manufacturing can be facilitated.

(Fourth embodiment)
A semiconductor device according to the fourth embodiment of the present invention will be described below with reference to FIG.

  An element isolation layer 102, a polycrystalline silicon wiring 103, a diffusion layer 104, and a silicide layer 105 are formed on the semiconductor substrate 101. On top of that, a tungsten wiring 107 and an interlayer film 108 with a planarized surface are formed with an interlayer film 106 with a planarized surface interposed therebetween. A plug 109 having a diameter of 200 nm made of tungsten using titanium and titanium nitride as a barrier metal is formed in a contact hole that penetrates the interlayer film 106 and the interlayer film 108 and reaches the silicide layer 105.

  An oxygen barrier film 410 is formed from the lower layer so as to cover the upper surface of the plug 109, which is a square of 400 nm on a side made of titanium aluminum nitride 100 nm, iridium 50 nm, and iridium oxide 50 nm and is 200 nm from the adjacent pattern. The oxygen barrier film 410 is embedded in a silicon oxide film 411a having a thickness of 150 nm and a silicon nitride film 412a having a thickness of 50 nm from the lower layer. On the oxygen barrier film 410 and the silicon nitride film 412a, a silicon oxide film 413b and a silicon nitride film 414a having a thickness of 550 nm are formed from the lower layer, and a circular opening having a diameter of 500 nm is formed in the silicon oxide film 413b. A 100 nm contact hole is formed so that the upper surface of the oxygen barrier film 410 is exposed. The side surfaces of the oxygen barrier film 410 are not exposed because the silicon nitride film 412a serves as a stopper.

  A lower electrode 415a made of 30 nm platinum is formed on the inner wall of the contact hole, and a strong bismuth layered perovskite oxide 60 nm composed of strontium, bismuth, tantalum and niobium is formed on the surface of the lower electrode 415a and on the silicon nitride film 414a. A dielectric capacitor insulating film 416 and an upper electrode 417 made of platinum 30 nm are formed.

  A semiconductor device manufacturing method according to the fourth embodiment of the present invention will be described below with reference to FIGS. 8 (a) to 8 (e) and FIGS. 9 (a) to 9 (d). A description of the same parts as those in the first embodiment will be omitted.

  First, as shown in FIG. 8A, an oxygen barrier film 410 is formed as in the first embodiment. In the fourth embodiment, the film thickness of iridium oxide in the oxygen barrier film 410 is 50 nm, and the first embodiment in which the film thickness is 200 nm is only that the film thickness of the iridium oxide is 150 nm thinner. Different. A silicon oxide film having a thickness of 600 nm is formed on the oxygen barrier film 410, and a silicon oxide film 411 planarized by CMP is formed so that the remaining film on the oxygen barrier film 410 becomes 200 nm.

  Next, as shown in FIG. 8B, the silicon oxide film 411 is etched to 50 nm below the oxygen barrier film 410 by etching back to form a silicon oxide film 411a.

  Next, as shown in FIG. 8C, a silicon nitride film 412 is formed to a thickness of 150 nm. Next, as shown in FIG. 8D, a planarized silicon nitride film 412a is formed by CMP or resist etch back so that the oxygen barrier film 410 is exposed.

  Next, as shown in FIG. 8E, after forming the silicon oxide film 413 at 550 nm and the silicon nitride film 414 at 50 nm, the oxygen barrier film 410 has a circular opening having a diameter of 300 nm. A photoresist 417 having a distance of 300 nm from the adjacent pattern is formed.

  Next, as shown in FIG. 9A, a circular opening having a diameter of 500 nm is formed by isotropic dry etching using plasma containing a gas containing C and F and a gas containing O. A silicon nitride film 414a having a distance of 100 nm from the adjacent pattern is formed. At this time, the silicon oxide film 413 is partially etched to form a silicon oxide film 413a.

  Next, as shown in FIG. 9B, the photoresist 417 is removed using plasma of a gas containing O. Next, as shown in FIG. 9C, the silicon oxide film 413a is etched by dry etching using plasma containing a gas containing C, H, F and a gas containing O, and the oxygen barrier film 410 and the silicon nitride film are etched. A part of the film 412a is exposed. At this time, the silicon nitride film 412a serves as an etching stopper, and the insulating film on the side surface of the oxygen barrier film 410 is not etched.

  Next, as shown in FIG. 9D, a platinum film is formed to a thickness of 30 nm by sputtering or CVD. Next, only the platinum film on the main surface is removed by CMP or resist etch back to form the lower electrode 415a. At this time, the silicon nitride film 414a serves as a CMP stopper or an etching stopper, and the insulating film around the opening is not etched. Next, a ferroelectric film made of a bismuth layered perovskite oxide containing strontium, bismuth, tantalum, and niobium is formed by MOCVD to 60 nm, and then platinum 30 nm is formed by sputtering, and the ferroelectric capacitor insulating film 416 is formed. Then, the upper electrode 417 is formed.

  As described above, according to the present embodiment, since the hard mask using the silicon nitride film 414a is used instead of the resist mask, the oxygen barrier film 410 is reached while preventing contact with the adjacent opening. In addition, an opening wider than the oxygen barrier film 410 can be formed, and the capacitor area can be increased.

  Further, by suppressing over-etching around the oxygen barrier film 410 by the silicon nitride film 412a, the film thickness of the oxygen barrier can be suppressed.

  Further, by using a silicon nitride film (412a, 414a) which is a general material used in a semiconductor as a hard mask or a stopper, manufacturing can be facilitated. In addition, since the capacitor insulating film is a ferroelectric film, the film thickness is increased, and the effect of expanding the opening becomes remarkable. Further, since the capacitor insulating film is a ferroelectric film, the oxygen barrier film thickness is increased, and the effect of suppressing over-etching around the oxygen barrier film becomes significant.

  Note that the silicon nitride film 412a in the fourth embodiment may be applied to the first embodiment, whereby the over-etching around the oxygen barrier film 110 can be further suppressed, and the oxygen barrier film thickness is also increased. It can be made thinner.

  In any of the first to fourth embodiments, the distance between the lower electrodes of adjacent capacitors can be made smaller than the diameter of the opening in which the lower electrode of the capacitor is formed.

In the first to fourth embodiments, a ferroelectric film made of a bismuth layered perovskite oxide containing strontium, bismuth, tantalum, and niobium is used as the capacitor insulating film. A high dielectric film may be used instead of the film. Examples of the material for the high dielectric film include BST (BaSrTiOx) having a perovskite structure and STO (SrTiOx). Furthermore, even promising as High-K gate dielectric materials (high-dielectric _{material), TiOx, Ta 2 O 5} , HfO 2, ZrOx, PrOx, and the like _{La 2 O 5, Al 2 O} 3.

  The reason why the oxygen barrier film (110, 210, 310, 410) is formed is that the ferroelectric film or the high dielectric film that becomes the capacitive insulating film needs to be crystallized in a high-temperature oxygen atmosphere. This is because the lower plug 109 is prevented from being oxidized and increased in resistance during this heat treatment.

  The semiconductor device and the manufacturing method thereof according to the present invention have an effect of securing a capacitor area without being in contact with an adjacent pattern and suppressing an overetching around the oxygen barrier film. It is useful as a semiconductor device having a capacitor having a body film as a capacitive insulating film, a manufacturing method thereof, and the like.

Sectional drawing which shows the semiconductor device which concerns on the 1st Embodiment of this invention Sectional drawing which shows the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention Sectional drawing which shows the manufacturing method of the semiconductor device which concerns on the 1st Embodiment of this invention Sectional drawing which shows the manufacturing method of the semiconductor device which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows the semiconductor device which concerns on the 3rd Embodiment of this invention. Sectional drawing which shows the manufacturing method of the semiconductor device which concerns on the 3rd Embodiment of this invention. Sectional drawing which shows the semiconductor device which concerns on the 4th Embodiment of this invention. Sectional drawing which shows the manufacturing method of the semiconductor device which concerns on the 4th Embodiment of this invention. Sectional drawing which shows the manufacturing method of the semiconductor device which concerns on the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Semiconductor substrate 102 Element isolation layer 103 Polycrystalline silicon wiring 104 Diffusion layer 105 Silicide layer 106 Interlayer film 107 Tungsten wiring 108 Interlayer film 109 Plug 110 Oxygen barrier film 111, 111a, 111b Silicon oxide film 112 Platinum film 112a Lower electrode 113 Ferroelectric Body capacitance insulating film 114 Upper electrode 115 Photoresist 210 Oxygen barrier film 211, 211a, 211b Silicon oxide film 212a Lower electrode 213 Ferroelectric capacitor insulating film 214 Upper electrode 215 Photoresist 310 Oxygen barrier film 311, 311a, 311b Silicon oxide film 312 Silicon nitride film 312a CMP stopper film 313 Platinum film 313a Lower electrode 314 Ferroelectric capacitor insulating film 315 Upper electrode 410 Oxygen barrier film 311 411a Con oxide film 412,412a silicon nitride film 413,413a, 413b silicon oxide film 414,414a silicon nitride film 415a the lower electrode 416 ferroelectric capacitive insulating film 417 upper electrode 418 photoresist

Claims (13)

A conductive oxygen barrier film formed on the substrate;
A first insulating film that covers the side and upper side of the oxygen barrier film and has an opening that exposes the upper surface of the oxygen barrier film;
A lower electrode formed along the bottom and side surfaces of the opening;
A second insulating film formed between a side surface of the opening and the lower electrode;
A capacitive insulating film formed on the first and second insulating films and along the surface of the lower electrode;
An upper electrode formed along the surface of the capacitive insulating film,
The opening is formed such that at least a part of the bottom surface of the opening protrudes from the top surface of the oxygen barrier film, and the bottom surface of the protruding portion is positioned below the top surface of the oxygen barrier film, thereby A groove region comprising the protruding portion around the upper surface of the oxygen barrier film;
The semiconductor device, wherein the trench region is filled with the second insulating film. 2. The semiconductor device according to claim 1 , wherein the first insulating film is a silicon oxide film, and the second insulating film is a silicon nitride film. The semiconductor device according to claim 1 or 2, wherein the capacitive insulating film is a ferroelectric film or a high dielectric film. Forming an insulating film so as to cover the oxygen barrier film formed on the substrate;
Forming an opening reaching the oxygen barrier film in the upper surface region of the oxygen barrier film in the insulating film using a mask;
Forming the groove region in a portion of the opening protruding from the oxygen barrier film by expanding the opening to the outside of the upper surface region of the oxygen barrier film by isotropic etching;
Forming a lower electrode along the bottom and side surfaces of the opening including the groove region;
Forming a capacitive insulating film on the insulating film and on the surface of the lower electrode;
And a step of forming an upper electrode along the surface of the capacitor insulating film. Forming an insulating film so as to cover the oxygen barrier film formed on the substrate;
Forming an opening that does not reach the oxygen barrier film in the upper surface region of the oxygen barrier film in the insulating film using a mask;
Expanding the opening to the outside of the upper surface region of the oxygen barrier film by isotropic etching, and allowing the opening to reach the oxygen barrier film;
Forming a lower electrode along the bottom and side surfaces of the opening;
Forming a capacitive insulating film on the insulating film and on the surface of the lower electrode;
And a step of forming an upper electrode along the surface of the capacitor insulating film. The step of forming the lower electrode includes forming an electrode film on the insulating film and along the bottom and side surfaces of the opening, and then removing only the electrode film on the insulating film by CMP or a resist etch back method. the method of manufacturing a semiconductor device according to claim 4 or 5, characterized in that formed by. Forming a first insulating film so as to cover the oxygen barrier film formed on the substrate;
Forming an opening reaching the oxygen barrier film in the upper surface region of the oxygen barrier film in the first insulating film using a mask;
Forming the groove region in the portion of the opening that protrudes from the oxygen barrier film by expanding the opening to the outside of the upper surface region of the oxygen barrier film by isotropic etching;
Forming a second insulating film on the first insulating film and along a bottom surface and a side surface of the opening including the groove region;
Leaving only the second insulating film formed on the side surface of the opening and the groove region, and removing the second insulating film in other portions;
Forming an electrode film on the first insulating film, along the bottom surface of the opening and the surface of the second insulating film;
Forming a lower electrode made of the electrode film in the opening by removing the electrode film other than in the opening by a CMP method;
Forming a capacitive insulating film along the first and second insulating films and the lower electrode surface;
And a step of forming an upper electrode along the surface of the capacitor insulating film. 8. The method of manufacturing a semiconductor device according to claim 7 , wherein the first insulating film is a silicon oxide film, and the second insulating film is a silicon nitride film. Forming a first insulating film so as to cover the oxygen barrier film formed on the substrate;
Forming a second insulating film on the first insulating film;
A step of isotropically etching the second insulating film using a mask to form an opening in the second insulating film in a region including the upper surface region of the oxygen barrier film and wider than the upper surface region; When,
Etching the first insulating film using the second insulating film as a mask to reach the opening to the oxygen barrier film;
Forming a lower electrode along the bottom and side surfaces of the opening;
Forming a capacitive insulating film on the second insulating film and on the lower electrode surface;
And a step of forming an upper electrode along the surface of the capacitor insulating film. 10. The method of manufacturing a semiconductor device according to claim 9 , wherein the first insulating film is a silicon oxide film, and the second insulating film is a silicon nitride film. Forming a first insulating film on the substrate and on the oxygen barrier film formed on the substrate so as to protrude from the surroundings ;
Planarizing the first insulating film so that the upper surface of the oxygen barrier film is exposed by CMP or resist etchback;
Forming a second insulating film on the oxygen barrier film and the first insulating film;
Forming an opening reaching the oxygen barrier film in the second insulating film over a region including the upper surface region of the oxygen barrier film and wider than the upper surface region ;
Forming a lower electrode along the bottom and side surfaces of the opening;
Forming a capacitive insulating film on the second insulating film and on the lower electrode surface;
And a step of forming an upper electrode along the surface of the capacitor insulating film. 12. The method of manufacturing a semiconductor device according to claim 11 , wherein the first insulating film is a silicon nitride film, and the second insulating film is a silicon oxide film. The method of manufacturing a semiconductor device according to any of claims 4 to 12, wherein the capacitive insulating film is a ferroelectric film or the high dielectric film.

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