TW200425300A - Method of manufacturing semiconductor device - Google Patents

Abstract

The present invention provides a manufacturing method for semiconductor device, which can eliminate the penetration of boron gate insulative film from ion injection into gates, and also eliminate the reduction of mobility of channel areas. The manufacturing method according to the present invention includes the following steps: a gate insulative layer forming process, for forming the gate insulative layer on the active area of the semiconductor substrate; a nitrogen introduction process for introducing nitrogen from the surface of the gate insulative layer with active nitrogen; and, an annealing process for conducting the annealing process in the NO gas environment, so as to maintain high concentration distribution of nitrogen on the surface during introducing nitrogen into the gate insulative layer, and maintain the low concentration distribution at the interface to the semiconductor substrate.

Description

200425300 发明 Description of the invention: [Leadership of the technical office to which the invention belongs] FIELD OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device having a nitrogen-containing gate insulating film. BACKGROUND OF THE INVENTION In order to improve the integration degree and operating speed of semiconductor integrated circuits, MOSFETs (Metal Semiconductor Field Effect Transistors) are miniaturized and the closed-edge film 10 is thinned. Generally, the idler electrode formed on the gate insulating film is formed by a polycrystalline silicon layer 'or a laminated layer of polycrystalline silicon layer and Wei Wu. The polycrystalline layer is usually ion-implanted with impurity f at the same time as the source / nano area. Gate of surface channel type p-channel MOSFET. Source / inverted region 'ion implantation is p-type. When the gate insulating film becomes thin, the ion implanted into the gate electrode of the surface channel type p-channel 15 MOSFET, that is, the p-type impurity, that is, the shed, penetrates the closed insulating film, and then reaches the region. When the shed is injected into the n-type region, that is, the channel region, not only the threshold value is changed, but the mobility is also deteriorated. The introduction of nitrogen into the gate insulating film is well known to inhibit the penetration of boron. In order to introduce nitrogen into the silicon oxide layer, a method of heating a silicon substrate by heating with a resistance heating lamp in a nitric gas atmosphere such as NH3 gas, NO gas, Nβ gas, etc. has been well known. . A method for introducing a higher concentration of nitrogen onto the surface of a silicon oxide film using a nitrogen plasma is known. Gate and channel area

When the gate insulation film becomes thinner, the tunnel current flows through the 5 200425300 5 domain, and the phenomenon that the gate leakage increases is also known as ^ ^ _. If you use a dielectric permittivity insulating film with a higher permittivity, and a gate insulating film of Θ generation silicon (one cent), you can change the thickness of the inverting capacitor to the thickness of the isoamine and change the physical thickness. The film thickness is thickened to suppress the gate leakage current. Nitrogen oxides, lice and lice silicon, in general, the permittivity is higher than that of silicon oxide, so it is effective to reduce the physical film thickness on one side and the other side to suppress the inversion of the capacitance. Japanese Patent Application Laid-Open No. 2002-198531 proposes to introduce nitrogen into a silicon oxide insulating film formed on a stone substrate through a long-distance galvanic polynitride, and then at a temperature of 800C to 1100C at The gate insulating film is oxidized and annealed in an atmosphere of n20, thereby redistributing the nitrogen, and forming a film with a uniform-nitrogen collapse. In addition, chrome is used to form a gate edge film with an average gas / age of 6at%, such as 8at% and 10at%, so as to obtain a long-life, high-reliability transistor.

Here, the so-called remote plasma nitriding means that in a plasma generating chamber different from the 15 chambers where the substrate is housed, a nitrogen plasma is generated by microwaves or the like, and the active nitrogen is transferred to a processing chamber for nitrogen. In terms of processing. If the annealing is performed in an N2O atmosphere, a part of the n2O gas may be considered to be decomposed into N2, 02, NO, etc., so as to control the uniformity in the wafer surface by controlling the increase in the oxide film thickness and the increase in nitrogen concentration. The 20-side uniformity between wafers may cause problems. Japanese Patent Application Laid-Open No. 2002-110674 further proposes that: as nitrogen enters near the interface on the Si substrate side, the mobility of MOST (MOS Transister: metal-oxide semiconductor transistor) decreases, so in order to suppress the nitrogen concentration near the substrate interface And reduce the gate leakage current, and introduce many nitrogen matters. There are proposals ...

6 200425300 Pre-guided eight-off + ^ M ★ Shi Xi oxynitride m, using nitrogen carving to refine the suppression of nitrogen in the vicinity of the free radical nitrogen, and to the-substrate interface [invention of the inner surface of the soil Degree matters. 5 SUMMARY OF THE INVENTION The object of the present invention is to provide a semiconductor device manufacturing method for a MOSFET with thin and advantageous characteristics, and another object of the present invention is to provide a ionic, The gate electrode is a method for fabricating a semiconductor device that penetrates the edge film and suppresses a decrease in the movement of the channel region. In accordance with the first aspect of the present invention, a method for manufacturing a semiconductor is provided, which includes: (i) a gate insulating layer forming process for forming a gate insulating layer on an active region of a semiconductor substrate; (ii) a nitrogen introduction project through Active nitrogen is introduced into nitrogen from the surface side of the above-mentioned gate insulation layer; and the annealing process is performed in an atmosphere of NO gas in order to maintain a high concentration distribution of nitrogen on the surface side in the gate insulation layer with nitrogen introduced, and Low concentration distribution is maintained at the interface with the semiconductor substrate. 20 Brief Description of Drawings Figures 1A to 1F are sectional views and diagrams, and are used to explain the experiments and results performed by the inventors. Figures 2A to 2D are sectional views and diagrams, and are used to explain the experiments performed by the inventors and their results. 200425300 Figures 3A and 3B are tables and charts showing conditions and results of other experiments performed by the present invention. ^ Figures 4A and 4B are tables and diagrams showing conditions and results of more experiments performed by the inventors. 5 Figures 5A to 5D are cross-sectional views of a semiconductor substrate, and are used to explain a method for manufacturing a semiconductor device according to an embodiment of the present invention. Figures 6A and 6B are tables and graphs showing conditions and results of other experiments performed by the present inventors. Figures 7A, 7B, and 7C are cross-sectional views that schematically show the structure of a remote electric gifting device, a decoupling RF nitrogen plasma device, and the structure of a gate insulation layer using a high-K material. . L embodiment; 3 Detailed description of the preferred embodiment If nitrogen is introduced into the silicon oxide film, the gate insulating film of boron can be effectively prevented from penetrating when the gate is implanted with boron ion implantation. However, with the thinning of the insulating film, it becomes difficult to prevent the penetration of boron, which leads to the interface between the insulating film and the Shixi substrate. Once the deletion reaches the channel area, it will reduce the mobile robustness. In addition, the boron concentration at the interface tends to be uneven. The active nitrogen generated by the plasma is introduced into a silicon oxide film or a silicon nitride oxide silicon film, thereby obtaining a nitrogen concentration distribution having a peak on the surface of the insulating film and in the film. By using such plasma nitriding, more nitrogen can be introduced while suppressing the nitrogen concentration in the interface with the substrate. High nitrogen concentration can effectively inhibit the penetration of boron. In addition, by introducing more nitrogen, the permittivity of the insulating film can be increased. 8 200425300 While reducing the reverse capacitance conversion thickness (Teff), the physical film thickness can be changed while suppressing the gate effectively. Leakage current. By reducing the nitrogen concentration in the interface between the insulating film and the silicon substrate, the decrease in the mobility in the channel region can be suppressed. In addition, degradation of 5 NBTI (negative bias temperature instability) characteristics can be effectively suppressed. The NBTI characteristic is a degradation characteristic when the temperature is increased by increasing the stress. The technique of generating nitrogen plasma at a place away from the substrate and introducing active nitrogen to the substrate is called a non-damaging surface process without adding damage to the substrate. 10 Shumingzhe believes that although the active nitrogen of Qian Zhongzhong's students is introduced into an insulating film of a silicon substrate arranged from the plasma, it is possible to add some kind of damage to the substrate. In order to recover this damage, the annealing treatment must be effective at a higher temperature than the nitrogen introduction process ^. The effect of annealing treatment was investigated. Inspection of the sample production process. 20

As shown in Figure 1A, on Shixi substrate! The surface is formed to cover ^ = cover ', and an anisotropic surname engraving is performed on Mei 1 to form a groove 2 for separation. Accumulate insulating layers such as oxides to fill the element separation. 猎 Chemical mechanical polishing (CMP) to remove useless ^ layers on the spherical surface of Shixi substrate 'to form-base gap_ (ST1) and red element separation [3 "The shallow Han isolation film (ST1) is formed by burying an insulating film in a trench" as shown in Fig. 1B. In an oxygen-added atmosphere, an emulsified film 5 having a thickness of h is formed on a substrate. Active surface 4 surface. X · 9 " U4253〇〇 As shown in Fig. 1C, the active nitrogen is derived from a nitrogen plasma excited with 1.5W microwave, and this active nitrogen is used to introduce nitrogen into the gate in the atmosphere of 45 (rc, And film 5. After nitrogen is introduced on the surface of the oxide film, it becomes a nitrided oxide stone film &. Active nitrogen introduced using a remote plasma nitriding device. This remote plasma nitriding can be obtained from the United States. Acquired from Santa Clara, Calif. (Inch ^ Xi Xi Jin Jin) by Abret Material Company (77. Today, 7 Yu & 7 small companies). Figure 7A shows the remote plasma nitriding The general structure of the device. The M] gas is introduced into the plasma generation chamber 21 to generate a nitrogen plasma. The nitrogen plasma generates 10 • [nitrogen-generating (radical) 'is supplied to the reaction chamber 22. In the reaction chamber 2 A lamp heating device 23 containing a large number of lamps is provided to heat the wafer 24. As shown in FIG. 1D, annealing treatment is performed in a nitrogen atmosphere of 105 (rc) to cause damage to the substrate caused by the introduction of active nitrogen. Recovery. The silicon nitride oxide film 5x, that is, becomes a silicon nitride oxide film under annealing treatment. As shown in Figure 1E, the gate is insulated On the film, as many layers as 15 μm thick are deposited by using ⑽ and a protective layer pattern is used to pattern the ㈣2 灿 ng), thereby forming a gate length of 0.5 to 6 m. Gate After the insulating film 5y is also patterned, it becomes the gate insulating film 5z. After the gate is patterned, the P-type impurity (ie, B) is ion-implanted to form the extended region 7. After that, the chemical vapor deposition (cvd) ) Stack a large thickness of about 60 fine oxide stone film on the substrate so as to cover the interfacial electrode ^ and carry out reactive ion engraving to remove the plutonium oxide on the flat surface, leaving only on the interfacial wall Side wall spacers 8. After the formation of the side wall spacers 8, the P-type impurity B was ion-implanted to form a high-concentration secretion region 9. In the ion implantation process, the gate 6 was also implanted with p-type 10 25 025 300 sub-types. Impurity B. Thereafter, an interlayer insulating film is formed, and then an opening for exposing the source / drain region and the gate electrode is formed to form an electrode. Thereby, a sample S1 is obtained. The activity shown in FIG. After the nitrogen introduction process 5, the annealing treatment shown in FIG. 1D is not performed, as shown in FIG. 1E A comparative sample S2 was fabricated with a MOSFET formed. Figure 1F is a pattern showing the characteristics of the two types produced. In the figure, the horizontal axis represents Vq-Vth minus the threshold value from the gate voltage ^^ in the unit V. Vertical The axis system is expressed in units ㈤ ^^. Multiplying the inversion capacitance conversion film η 仃 10 by the mutual conductance Gm, then multiplying the normalized mutual conductance of the ratio of the width% of the channel area to the length B by W / L. The thickness of the insulating film and the size of the channel area are all standardized. After the introduction of the active nitrogen, the characteristics S1 of the sample S1 which is annealed in a nitrogen atmosphere at a temperature of 1050 ° C is a kind of Compared with the characteristic S2 of the annealing treatment in the nitrogen atmosphere 15, the mutual conductance is higher in almost the entire area. This clearly shows that the characteristics of the MOSFET are improved by the annealing treatment. This can be considered as a result of improving the carrier mobility and increasing the saturation current. After doing so, although it was identified that the characteristics of the transistor were improved by annealing 20 after the introduction of the active nitrogen, the matter of how the improvement of the characteristics was changed according to the conditions of the annealing treatment was further investigated. As the atmosphere users for the annealing treatment, nitrogen (N2), nitric oxide (N), and oxygen (O2) were used. First, by the same process as the process shown in FIG. 1A, an element isolation region 3 is formed on a silicon substrate. Next, by the same process as shown in Fig. 1B, 11 5 = the same process, the wire plate was thermally oxidized in the phase air temperature to form a gate oxide film 5 having a thickness of 1.2 nm. The sample weight is shown in Figure 1C and the engineering weight shown in Figure 1C = nitriding at the stage of introducing nitrogen, the gate insulation-like film thickness, as measured by the name and elliptical instrument, is 1.457nm around ^ 2A As shown in the figure, the third sample was deleted in nitrogen atmosphere 2 after introducing nitrogen. (: Line reading theory. This button is an annealing treatment in an inactive gas. 10

As shown in Fig. 2B, the fourth sample S4 was annealed at 950 ° C in a nitrogen atmosphere after introducing nitrogen. This annealing treatment is an annealing treatment accompanied by nitrification. Thereafter, it was annealed in a nitrogen atmosphere. At this stage ', the film thickness of the gate insulating film measured with an ellipsometer was • 538 nm. Compared with the third sample, it was found that an annealing treatment of No. 15 in No. 15 was added to the fourth sample. The film thickness increased due to the annealing treatment in ^^ 〇 is ㈨ to ㈨.

As shown in FIG. 2C, the fifth sample S5 was subjected to an annealing treatment of 10,000 ° C in an oxygen (02) atmosphere after nitrogen introduction. This annealing treatment is an annealing treatment accompanied by oxidation. Thereafter, a 1050 t: L fire treatment was performed in a nitrogen atmosphere. Compared with the second sample, it was found that an additional annealing treatment in the second sample was added to the second sample. 20 Moreover, each annealing process is performed by rapid thermal annealing RTA, as long as it is an extreme time. Thereafter, the same insulated gate and source / drain regions as in the second sample were formed. Figure 2D is a chart showing the characteristics of the third, fourth, and fifth samples. The horizontal axis and vertical vehicle are the same as the first ιρ_. The characteristic S3 of the third sample S3, which has some differences in the thickness of the gate insulating film and the temperature when the active nitrogen is introduced from the first sample, is approximately the same as ^ in the figure. The characteristics of the samples which were annealed (nitrided, oxidized) and annealed in the NO atmosphere after the introduction of active nitrogen showed a significant improvement. After the introduction of the active nitrogen, it was surfaced in an oxygen atmosphere. (: The (oxidation) annealing S5, S5 shows the intermediate characteristics of the two. 10

Summarizing these results, it is clearly shown that the mutual conductance increases when the annealing treatment is performed after the introduction of active nitrogen. Although the annealing treatment in the oxygen atmosphere 'and the retreat of the nitrogen atmosphere and the treatment of the towels will make each other conductive, it will raise the south', but when the nitriding oxidation annealing in the NO atmosphere is carried out, it becomes conductive to each other. highest. This is because the inventor believes that if annealing is performed in a No atmosphere, a silicon-oxygen-nitrogen (Si_O_N) bond is effectively formed near the interface on the substrate side.

However, annealing treatment in an oxidizing or nitriding oxidizing atmosphere can cause a change in the substrate, or nitriding oxidation, to make the gate insulating film thicker. If it is used as a transistor with an effective gate insulation film thickness of 2nm or less, the annealing treatment in a surrounding gas with a small increase in the film thickness should be more suitable. The increase of the insulating film achieved by the annealing treatment in the NO gas atmosphere should preferably be 0.2 nm or less. To obtain a gate insulation film with a thickness of 1.7nm or less, the initial oxide film should be made 1.5 to 20nm. As described in the prior art, it has been proposed to introduce active nitrogen (free radicals) into a silicon oxynitride diet. The inventor's measured the reliability of a semiconductor device having an insulating film formed by the following two manufacturing methods, that is, TDDB (time dependent dielectric breakdown). (1), (2) of 13 200425300 Manufacturing method ic fir w τ, oxide film thickness, active nitrogen introduction, no heat treatment, n2 treatment, although the order of rotation is different, each treatment content is the same. (1) After the thermal oxide film is formed, heat-treat it with NO gas atmosphere, then introduce nitrogen by active nitrogen, and then heat the gate insulation film treated with krypton gas atmosphere 5; and (2) to be formed After thermally oxidizing the film, activated carbon is used to introduce nitrogen, and then heat treatment is performed in a NO gas atmosphere, and then a gate insulation film is subjected to heat treatment with a higher temperature thoron gas atmosphere. When the above measurement is used to compare the 10 rate of the product below the criterion after the stress is applied, the sample of (1) is 0%, but the sample of (2) is 88%. This results in a large gap. That is, the sample of (2) has a nitrogen distribution in the insulating film that is approximately the same as that of the sample of (1), but there is a large difference in the effect of reliability. The inventors believe that this reason is that under the heat treatment of NO atmosphere 15 after the active nitrogen introduction treatment, a silicon-oxygen-nitrogen (Si-O-N) bond is efficiently formed near the interface on the substrate side. In addition, after annealing in a NO atmosphere, the heat treatment in a higher temperature N2 atmosphere was performed in order to improve the characteristics of NBTI, and it is not a necessary process. 20 As far as plasma nitridation devices, in addition to remote plasma devices, it is known to be available from the same company in Santa Clara, California (Inch > Xi Xi Jin Jin) Abret Material (7 7 ° present彳 社) obtained decoupling RF nitrogen plasma device. Fig. 7B is a schematic diagram showing the structure of a decoupling RF nitrogen plasma device. In terms of this device, 14 200425300, a nitrogen plasma is generated by RF excitation of a coil 26 provided on the top of the reaction chamber 25, and the reaction chamber 25 houses a sample 27 in the lower part. Nitrogen plasma was generated only in the area along the upper wall of the reaction chamber, away from sample 27. Hereinafter, this device is referred to as a DPN. '5 Using a DPN nitriding device, two samples were formed. Figure 3A shows the production conditions of two types of samples S6, S7 and comparison sample S8. First, through the same process as that shown in Figures IA and 1B, a lamp annealing device was used to form a silicon oxide film with a thickness of 0.85 nm in an oxygen atmosphere at 900 ° C. Thereafter, the plasma plasma was excited with RF power of 700 W in the DPN device, and then the active nitrogen was introduced into the oxide second film of a substrate disposed below in a room temperature atmosphere. After the sixth sample S6 ′ was subjected to oxidation annealing treatment (RTO) in a reduced pressure oxygen atmosphere at 1000 ° C, an annealing treatment (RTA) was performed in a nitrogen atmosphere at 105 ° C. ). For the seventh sample S7, nitriding oxidation annealing (RTNO) was performed in a NO gas atmosphere at 950 ° C after the introduction of active nitrogen, and then an annealing treatment was performed in a nitrogen atmosphere at i50 ° C ® ( RTA). For comparison, sample S8, which uses only a silicon oxide film to form the gate electrode, has also been made into two types. Figure 3B shows the measurement results of these samples. The horizontal axis is in units, ^ m represents the inversion electric valley change film thickness Teff. The vertical axis is expressed in units (A / cm2). The characteristics of the sample S8 where the gate leakage film V is formed of a silicon oxide film using only a silicon oxide film. S8 ′ are two points represented by the X symbol; when extrapolated, it becomes a straight line. The characteristic S6 of the sixth sample S6 is located at 15 200425300 τ of the characteristic S8 of the comparative sample 8, which shows that the gate leakage current can be reduced. The measurement point S7 of the seventh sample S7 is a nitriding oxidation annealing treatment in NO, and its oxidation is suppressed and is thinner than the measurement point S6. In addition, it is lower than the characteristic S8 and shows that the gate leakage current can be reduced similarly to the sample S6. 5 In the characteristics of Fig. 3B, the reduction degree of brake leakage current is about the same for the two samples. S6 and S7. Sample No. 8 was made with an effective gate insulation film thickness of 0.013 nm. In addition, it has excellent mutual conductance. Regarding the characteristics of semiconductors, the saturation current can be increased by 3.6% in MOS electro-oscillators with a gate length of 40 nm. Φφ 10 Furthermore, by introducing secondary ion mass analysis (SIMS), investigations have been conducted on the introduction of gates with active nitrogen. How to distribute the nitrogen of the insulating film. DPN was used as the active nitrogen introduction device, and annealing was performed after the introduction of active nitrogen in an oxygen atmosphere and a NO atmosphere. The table in Figure 4A shows the production process of two types of samples. The ninth 15 sample S9 was formed into a silicon oxide film with a thickness of 0.8 nm by a lamp annealing device in an oxygen atmosphere at 900 ° C, and then introduced into a room temperature atmosphere using a 700 W decoupled rf nitrogen plasma ( DPN) active nitrogen in the gate oxide film. Thereafter, annealing treatment (rT0) was performed in a reduced-pressure oxygen atmosphere at iooo ° C, and then annealing treatment (RTA) was performed in a nitrogen atmosphere at 1050 ° C. 20 The tenth sample S10 is the same as the ninth sample S9, and a silicon oxide film with a thickness of 0.8 nm is formed. After introducing active nitrogen through a DPN device, an annealing treatment in a gas atmosphere of 950 t: 2v0 is performed, and then An annealing treatment (RTA) was performed in a nitrogen atmosphere of 1050 t. Figure 4B is a graph 'showing the measurement results of these two kinds of samples. The axis system represents the distance from the surface in units of nm, and the vertical axis system represents the measured nitrogen concentration in units (at 0 ms / CC). The characteristic S9 of the samples annealed in an oxygen atmosphere has a higher peak near the surface and reduces the nitrogen concentration one by one at the same time as the depth. Although the change in the nitrogen concentration of '5 with a single digit or more was displayed in the measurement range, there was an interface between the gate insulating film and the Shi Xi substrate in the middle. · The thickness of the nitrided oxide film is 1.324nm; the peak of the nitrogen concentration is 8.6at%; the nitrogen concentration in the interface with the substrate is 3.6at%. The nitrogen concentration at the interface is less than " 2 of the peak nitrogen concentration. The characteristic S10 of the sample S10 which is annealed in the NO atmosphere after the introduction of active nitrogen is: the peak on the surface side is expanded to a certain level, but the distribution of oxygen resulting from the introduction of active nitrogen and the atmosphere in the NO atmosphere The nitrogen distribution resulting from the annealing must be contained in it. After that, it shows that the nitrogen concentration of bit S9 is a little higher, and the trend of decrease in the number of gates is reduced. It also shows that the same distribution as that of characteristic S9 is formed from a certain depth position. The thickness of the nitrided oxide film is 1.174nm; the peak of the nitrogen concentration is 7-6at%; the nitrogen concentration in the interface with the substrate is 49at%. If the degree of nitriding oxidation is increased as much as possible, the nitrogen concentration at the interface of the substrate can be adjusted to be less than 1/2 of the peak nitrogen concentration. The substrate and interface nitrogen concentrations were both 5 at%. From the viewpoint of making the nitrogen concentration on the surface side higher and the nitrogen and temperature at the interface with the substrate lower, annealing in an oxidizing atmosphere such as 0 2 is more appropriate. However, the increase in film thickness is greater than the decrease in the oxidation atmosphere. From the standpoint of reducing the thickness of the nitrided oxide film and forming a transistor having an excellent driving force, annealing in a nitrided oxidizing atmosphere such as NQ is more appropriate. 17 Peak Γ 卩 — 敎 As a result, the nitrogen content has a 罙 degree on the face side of Zhaji County, and the interface to the same wire plate continues to decrease. Therefore, it can be seen that: ′ multi-nitrogen nitrogen is introduced into the leisure insulating film, which can effectively suppress deletion.

At the same time, the chlorine concentration at the interface of the substrate should be suppressed to a decrease in the mobility in the control channel area of 5 or less. P In addition, the residual oxygen-cutting surface has been shown to have active nitrogen, which has been tested under the conditions that the excitation energy of the light RF plasma can be reduced from 7 to 5.

-The table of Figure 6A shows three types of production processes. Tenth. DS11 series, in a 900C oxygen atmosphere, the film was formed by anneal with a degree of oxidation of 0.8 W at a wavelength of 0.8 nm, using a nitrogen gas of 5 nanometers: in a room temperature atmosphere without a bias electric field Active nitrogen is introduced into the gate oxide film (deleted). Thereafter, annealing (RTO) was performed in a reduced-pressure oxygen gas of 1 () _, and then annealing 15 (RTA) was performed in a nitrogen atmosphere of 1050t.

* The twelfth sample S12 is the same as the eleventh sample. In the 9000c oxygen flood gas, #the oxide annealing film with a thickness of 08 nm is formed by a lamp annealing device. RF nitrogen electropolymerization introduces active nitrogen into the gate oxide film (DPN) in a room temperature atmosphere. After that, an annealing treatment (RTNO) was performed in a reduced-pressure NO atmosphere 20 of 95 ° T, and the temperature was further reduced. Annealing treatment (RTA) was performed in a nitrogen atmosphere of 0.05 t. The thirteenth sample S13 is the same as the eleventh sample. The silicon oxide film with a thickness of 0.8 nm was formed by a lamp annealing device in a 900-degree oxygen atmosphere, and a 500W decoupling RF was used. , RF nitrogen plasma introduced 18 200425300 active nitrogen into the interlayer oxide film (DPN) in a room temperature atmosphere. Thereafter, annealing treatment (RTO) was performed in a reduced-pressure oxygen atmosphere at 100 ° (rc), and then annealing treatment (RTNG) was performed in a reduced-pressure atmosphere of 95.0 ° C, followed by a nitrogen atmosphere. Annealing treatment (RAT) was performed in the air. After annealing treatment in the NO atmosphere, those who perform RTA at high temperature are for the purpose of improving the characteristics of NBTI, and are not a necessary process. Figure 6B, The measurement results are shown for three types of samples. The horizontal axis | shows the depth from the surface in units of nm; the vertical axis shows the measured nitrogen concentration in units (at 0 m / cc). ^ 1〇 The tenth-sample S11, which has been annealed in the atmosphere of money, has the characteristic S11, which has a higher peak near the surface, and the carbon concentration gradually decreases with the depth. Within the measurement range, the nitrogen concentration above the i-bit number changes. The interface between the gate insulating film and the silicon substrate is halfway there. The film thickness of the nitrided oxide film is L189nm, and the peak of the nitrogen concentration is I5 7.5at%; the nitrogen concentration in the interface with the substrate is a. The nitrogen concentration is less than 1/2 of the peak nitrogen concentration. After the introduction of active nitrogen, in a NO atmosphere The twelfth Lumba with annealing treatment. ≪ ^ 12's characteristic S12, the peak near the surface increased a little, and expanded. After that, although it showed a higher nitrogen concentration than characteristic S11, it showed 20 As the depth decreases, the amount of nitrogen increases when approaching the interface, showing a characteristic distribution of two peaks on the surface and the surface near the interface. The annealing treatment in the atmospheric atmosphere seems to favor the nitrogen in the boundary with the substrate The thickness of the nitrided oxide film is L170nm; the peak of the nitrogen concentration is 7.8at%; the nitrogen concentration at the interface with the substrate is 4.8at%. 19 After the introduction of active nitrogen, annealing is performed after the oxygen atmosphere. The characteristics S13 of the sample S13 of the younger brother who performed annealing in the NO atmosphere, the peak value on the surface side is the same as the characteristic S13 of the sample S13 in oxygen annealing. Although it seems to be different from the characteristic of S11, this is the secondary ion mass. The difference within the measurement error of the SIMS can be confirmed; if the amount of nitrogen near the interface is increased, the interface is effectively nitrided in the atmosphere of NO. The film thickness of the nitrided oxide film is a peak nitrogen concentration of 74. at%; interface with substrate The nitrogen concentration in the substrate is 2.4 at%. Although the active nitrogen is annealed in a NO atmosphere to improve the characteristics, the nitrogen concentration at the interface with the substrate can be suppressed to 5 at% or less. The conditions are selected to thereby The nitrogen concentration at the interface can be made less than 1/2 of 7 degrees of nitrogen on the surface. From the characteristics S12 and S13 of the samples S12 and S13, the nitrogen distribution is controlled and the nitrogen distribution annealed in the NO atmosphere is used. This judgment can realize various nitrogen distributions. The nitrogen can be introduced near the interface by annealing in a NO atmosphere under the shape of the distribution that is not deformed by the introduction of active nitrogen. It is also easy to realize that the interface between the gate insulation film and the substrate is different The request varies with the nitrogen concentration. Figures 5A to 5D are cross-sectional views based on the above experimental results, showing a manufacturing method according to an embodiment of the present invention. As shown in FIG. 5A, the element isolation region 3 is formed on the silicon substrate 1 by ST1. In the active region defined by the element isolation region of ST1, a desired ion implantation is performed to form an n-type well 4n and a p-type well 4p. Also, although only two wells are shown, a plurality of tiles can be formed at the same time. Perform 800 on the exposed silicon substrate surface. 〇The pyrolysis oxidation (pyr05 is 2 1 Γ ° η, forming an oxidation frequency 11 with a thickness of 7 fines. This pyrolysis method uses oxygen to oxidize the atmosphere of hydrogen combustion. The gate oxidation medium with a thickness of 7nm, It becomes a gate insulating film for making MOSFETs (metal oxide semiconductor field effect transistors) with an operating voltage of about 3V. In the active area of the MQSFET for the low-voltage operation of the wire, the growth of the oxide is refined 965. (: Oxidation in the oxygen atmosphere, the oxide thickness of the thickness of Unm is 2. The thickness M thin oxide film, for example, is used as a gate insulating film for making MOSFETs with an operating voltage of about 1 to 1.2V. ^ ^ Right there is natural oxidation on the surface of the silicon substrate. The natural oxide film is also removed in a reducing atmosphere such as hydrogen radicals.

10 A good silicon oxide film can be formed. can. Although the surface of the silicon which has been cleaned by oxidizing is known to form a gate insulating film having two thicknesses, it is possible to form a gate insulating layer having three or more thicknesses. 15 20 Under this oxidation, the thick oxide stone film 11 formed earlier also grows a few. Shaanxi with thin gate insulation film 12 also forms 11-type and ρ-type.

As shown in Fig. 5, the active nitrogen was introduced into the gate insulating films n, 12 in an atmosphere of 55CTC by using an RPN nitrogen plasma obtained from a 1.5kw microwave. Active nitrogen was introduced to make the gate insulator _x and 12x an oxygen nitride cut film. As shown in Section 5C®, annealing is performed in a gas atmosphere of 95 ° C. The gate insulating film is further oxynitrided with NO gas to restore damage. After performing this process, the gate insulating films 1ly, 12y are formed. Next, in order to suppress the degradation of NBTI characteristics, further annealing at a high temperature may be performed in a nitrogen atmosphere. Thereafter, a 100 nm polycrystalline silicon layer is formed on the gate insulation film, and a protective layer pattern of 20042125300 is used. The gate pattern is formed to form a gate with a gate length of 40 nm. The gate length is required. On the thin gate insulating film 12y, tf 'as described in 5D® will be used to select a patterned red gate and n region' pit. The protective layer mask of the return region is used as a mask, and ion implantation of the mouth-type impurity and P-type impurity is performed to make the extended region π). Thereafter, an oxygen-cut film was deposited with a thickness of about 60 nm, and rie was performed to form a sidewall.

Spacer 8. Filament separation poles (with sidewall spacers> 0 and η channel area, P channel area protective layer mask, _ impurities, p-type impurities are ion implanted to form source / drain regions 9η, 9ρ. 10 Record '在 依If necessary, the exposed second surface is chemically converted and covered with an interlayer insulating film. Then, an opening is formed in the interlayer insulating film 2 to form a lead-out plug, thereby forming necessary wiring and an interlayer insulating film. With a thin gate insulation layer and a thick interlayer insulation layer, the penetration of the thin interlayer insulation layer is also suppressed, 1, to form a CMOS integrated circuit that has suppressed the movement of the channel region by 15 degrees of movement reduction. -Pi 仄. 仄 往Bu

_ • 'Fujitsu JL / IUIU's effective gate insulation film thickness' can prevent the penetration of boron, and can suppress the reduction of the mobility of semiconductor devices. 20

As such, according to the above-mentioned embodiment, the insulating film may have a higher entrance surface side, a lower gas concentration at the interface with the silicon substrate, a snap gate insulating film penetrates, and the movement of the towel in the channel area may be suppressed. Degree decreases. Although the present invention has been described based on the above embodiments, the present invention is not limited to these embodiments. For example, depending on the purpose, it is possible to use the annealing in NO with non-producing gas instead of nitriding oxidation in the book. ^ 22 200425300 For users of insulating films formed on semiconductor substrates, it is possible to form f-type oxide oxide films containing the following nitrogen instead of oxide oxide films. A film of high-k material with a high permittivity on the silicon nitride oxide film can also be used. Fig. 7C shows that the high-layer material composed of a film not laminated with high_k (high permittivity) material has a permittivity that is significantly larger than that of oxidized stone. For example, a silicon oxide film 31 having a thickness of 0.58 nm is formed on a 3G surface of a slab by a lamp annealing device in an oxygen atmosphere of 75 Gt, and only ^^ nitrogen plasma is used in the chamber by decoupling by 500. Active nitrogen was introduced into the gate oxide film (DpN) in a warm atmosphere. After that, an annealing treatment (RTN0) in a NO gas atmosphere at 900 C was performed, and then an annealing area S (RTA) in a nitrogen atmosphere at 105 ° C was performed. This nitride oxide film has a thickness of 0.80 nm. Under the adjustment of substrate oxide film thickness, plasma nitriding strength, NO gas annealing temperature, time, etc., further thinning should be possible. On this oxynitride film, oxide films such as Al, Hf, Zr, etc., and high-k (high permittivity) oxide silicate films are formed to prevent the semiconductor substrate from reacting with the high-capacitance 15-rate material. And, it can provide gate insulation film with excellent reliability and driving ability. Various other changes, modifications, and combinations are obvious to the industry. Industrial Applicability 20 It is suitable for MOS transistors that are particularly miniaturized. [Explanation of explanation] Figures 1A to 1F are sectional views and diagrams, which are used to explain the experiments and results performed by the inventors. Figures 2A to 2D are sectional views and diagrams, and are used to explain the experiments conducted by the inventor and the results thereof. Figures 3A and 3B are tables and diagrams showing conditions and results of other experiments performed by the present invention. Figures 4A and 4B are tables and charts showing conditions and results of other experiments performed by the inventors. '' FIGS. 5A to 5D are cross-sectional views of a semiconductor substrate, and are used to explain a method of manufacturing a semiconductor device according to an embodiment of the present invention. Figures 6A and 6B are tables and graphs showing conditions and results of other experiments performed by the present inventors. 10 Figures 7A, 7B, and 7C are cross-sectional views that schematically show the structure of a remote plasma nitriding device, a decoupled RF nitrogen plasma device, and the structure of a high-K gate insulation layer. [Representative symbol table of main elements of the figure] 1 ... broken substrate 6 ... gate 2 ... groove 7 ... extended area 3 ... element separation area 7p, 7n ... extended area 4 ... active area 8 ... Side wall spacer 4η ··· η-type solution 9… source / ί and region 4ρ ··· ρ-type well 9η, 9ρ ... source / non-region 5 ... gate oxide film 11,12 ... gate insulation film 5x, 5y, llx, 12x ... Nitrided oxide stone film lly ... Gate insulating film 6 ... Gate 12y ... Gate insulating film 5y ... Gate insulating film Ig ... Gate leakage current 5z ... Gate insulating film S1 -S10 ... Sample 24 200425300

Vg ... gate voltage Gm ... transformed conductance

Vth ... threshold 25

Claims (1)

200425300 Scope of patent application: 1. A method for manufacturing a semiconductor device, including: a gate insulating layer forming process, which forms a gate insulating layer on the active area of a semiconductor substrate; 5 a nitrogen introduction project, which uses active nitrogen to Nitrogen is introduced on the surface side of the gate insulation layer; and the annealing process is an annealing process in a NO gas atmosphere on the semiconductor substrate. 2. The method for manufacturing a semiconductor device as described in item 1 of the scope of the patent application, 10 wherein: the aforementioned active nitrogen is nitrogen generated by radical nitrogen or plasma. 3. The method for manufacturing a semiconductor device as described in item 1 of the scope of the patent application, further comprising: an annealing treatment execution process, which is performed in a higher temperature inactive gas after the annealing treatment is performed in the aforementioned NO atmosphere. Annealed. 4. The method for manufacturing a semiconductor device according to item 1 of the scope of patent application, wherein: the film thickness of the gate insulating film under the annealing treatment in the aforementioned NO gas atmosphere is increased to 0.2 nm or less. 20 5. The method for manufacturing a semiconductor device according to item 1 of the scope of patent application, wherein: the annealing treatment in the aforementioned NO gas atmosphere is performed in a NO gas atmosphere at a higher temperature than the substrate temperature in the nitrogen introduction process. Go ahead, this nitrogen is introduced by active nitrogen. 26 200425300 6. The method for manufacturing a semiconductor device as described in item 1 of the scope of patent application, wherein: the annealing treatment in the aforementioned NO gas atmosphere is performed in a NO gas atmosphere diluted with an inert gas, the The inert gas 5 includes any of N2, Ar, and He. 7. The method for manufacturing a semiconductor device as described in item 1 of the scope of the patent application, further comprising: an annealing process, before the annealing treatment in the aforementioned NO gas atmosphere, in an oxygen atmosphere or by an inert gas. Annealing was performed in a diluted oxygen atmosphere of 10 ° C. 8. The method for manufacturing a semiconductor device according to item 1 of the scope of patent application, wherein: the gate insulating layer formed on the aforementioned active region is an insulating layer formed by thermally oxidizing the surface of the aforementioned semiconductor substrate, and has a thickness of 1.5 nm or less . 15 9. The method for manufacturing a semiconductor device according to item 1 of the scope of patent application, wherein: the gate insulating layer is an oxynitride layer containing a trace amount of nitrogen of 3 at% or less at the interface with the semiconductor substrate. 10. The method for manufacturing a semiconductor device as described in item 1 of the scope of the patent application, 20 wherein: the nitrogen concentration after the annealing treatment in the aforementioned NO gas atmosphere is 5 at% or less, and the nitrogen concentration is equal to that of the gate insulation layer. Semiconductor substrate and interface concentration. 11. The method for manufacturing a semiconductor device as described in item 1 of the scope of patent application, 27 200425300, which further includes: a natural oxide film removal process, which is performed before the semiconductor substrate surface thermal oxidation process in a reducing atmosphere. The substrate is annealed to remove the natural oxide film. 5 12. The method for manufacturing a semiconductor device according to item 1 of the scope of patent application, wherein: the project of forming a gate insulating layer on the active region of the aforementioned semiconductor substrate is to form insulating layers with different thicknesses depending on the region. 10 28